WO2024239155A1 - 一种电池单体及其制备方法、电池及用电装置 - Google Patents

一种电池单体及其制备方法、电池及用电装置 Download PDF

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Publication number
WO2024239155A1
WO2024239155A1 PCT/CN2023/095339 CN2023095339W WO2024239155A1 WO 2024239155 A1 WO2024239155 A1 WO 2024239155A1 CN 2023095339 W CN2023095339 W CN 2023095339W WO 2024239155 A1 WO2024239155 A1 WO 2024239155A1
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WIPO (PCT)
Prior art keywords
electrolyte
battery
battery cell
negative electrode
monomer
Prior art date
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Ceased
Application number
PCT/CN2023/095339
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English (en)
French (fr)
Inventor
刘润蝶
陈兴布
吴李力
孙信
宋佩东
李璇
董苗苗
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to CN202380071903.6A priority Critical patent/CN120035899A/zh
Priority to EP23937834.2A priority patent/EP4621906A4/en
Priority to PCT/CN2023/095339 priority patent/WO2024239155A1/zh
Publication of WO2024239155A1 publication Critical patent/WO2024239155A1/zh
Priority to US19/246,260 priority patent/US20250316753A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • 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
    • 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
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/60—Arrangements or processes for filling or topping-up with liquids; Arrangements or processes for draining liquids from casings
    • H01M50/609—Arrangements or processes for filling with liquid, e.g. electrolytes
    • 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
    • H01M2300/0085—Immobilising or gelification of electrolyte
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of battery technology, and in particular to a battery cell and a preparation method thereof, a battery and an electrical device.
  • Silicon and lithium metal have ultra-high theoretical gram capacity as anode materials, but the volume expansion rate of silicon and lithium metal has posed great challenges to their application. Batteries using silicon and lithium metal as anode materials will continue to expand and shrink during the cycle, exacerbating the extrusion of liquid electrolyte and making it impossible to reflux, resulting in a drop in the battery's cycle performance.
  • the present application provides a battery cell and a method for preparing the same, a battery and an electrical device, which can enable the battery to have both cycle performance and capacity performance.
  • the present application provides a battery cell, which includes: a negative electrode plate and an electrolyte, wherein the electrolyte includes a solid electrolyte and a liquid electrolyte.
  • the ratio of the fully charged thickness of the negative electrode plate to the uncharged thickness of the negative electrode plate is x
  • the ratio of the mass of the solid electrolyte in the electrolyte to the mass of the electrolyte is y.
  • the battery cell of the present application is combined with a liquid electrolyte and a solid electrolyte, and the ratio of the mass of the solid electrolyte to the mass of the electrolyte in the battery cell with negative electrode plates having different volume expansion rates is limited, which can reduce or avoid the extrusion of the liquid electrolyte, and the electrolyte can also provide a better lithium ion transmission rate, so that the battery cell can take into account both cycle performance and capacity performance.
  • the solid electrolyte is a heat-curable electrolyte.
  • the heat-curable electrolyte can be cured under heating conditions to form a solid electrolyte.
  • the curing temperature of the heat-curable electrolyte is 50° C. to 110° C.
  • the curing temperature of the heat-curable electrolyte is relatively low and is within the safe operating temperature range of the battery cell.
  • the liquid electrolyte includes a lithium salt and/or a sodium salt
  • the lithium salt includes any one or more of LiPF6, LiClO4, LiTFSI, LiFSI, LiBOB, LiDFOB, and LiNO3.
  • the present application provides a method for preparing a battery cell of the above embodiment, which comprises: preparing an electrode assembly, placing the electrode assembly into a shell, injecting a raw material for forming a solid electrolyte into the shell, solidifying the raw material for the solid electrolyte to form a solid electrolyte, and continuously injecting a liquid electrolyte into the shell containing the electrode assembly, and sealing it.
  • the preparation method of the battery cell of the present application is to first inject a raw material for forming a solid electrolyte into a shell containing an electrode assembly, and after the raw material for the solid electrolyte is solidified to form a solid electrolyte, a liquid electrolyte is injected into the shell containing the electrode assembly, so that a mixed electrolyte including a solid electrolyte and a liquid electrolyte can be obtained, that is, the mixing of the solid electrolyte and the liquid electrolyte is achieved by only two liquid injections, which simplifies the preparation process of the battery cell and reduces the process cost of the battery cell.
  • the solid electrolyte is a heatable solid electrolyte, and a heatable solid electrolyte is injected into the casing containing the electrode assembly. After curing the raw materials of the electrolyte, the raw materials of the heat-curable electrolyte are reacted at 50° C. to 110° C. for 3 h to 24 h to form a solid electrolyte.
  • the curing process of the heat-curable electrolyte of the present application is simple and can form a stable solid electrolyte.
  • the mass fraction of the polymerized monomer in the raw material, is 0.5wt% to 6.5wt%.
  • the polymerized monomer can be polymerized to form a high polymer under the action of an initiator, and the high polymer absorbs part of the liquid electrolyte to form a solid electrolyte, thereby obtaining an electrolyte composed of a liquid electrolyte and a solid electrolyte.
  • the mass fraction of the initiator in the raw material is 0.1wt% to 0.5wt%.
  • the polymerizable monomer can polymerize under the action of the initiator to form a polymer, and the polymer absorbs part of the liquid electrolyte to form a solid electrolyte, thereby obtaining an electrolyte composed of a liquid electrolyte and a solid electrolyte.
  • the polymerizable monomer has an unsaturated double bond.
  • the polymerizable monomer having an unsaturated double bond can be polymerized under the action of an initiator to form a high polymer, and the high polymer absorbs part of the liquid electrolyte to form a solid electrolyte.
  • the polymerizable monomers include any one or more of ester monomers, carbonate monomers, sulfone monomers, isocyanates, amide monomers, nitrile monomers, and fluorinated monomers.
  • the above polymerizable monomers can be polymerized under the action of an initiator to form a polymer, and the polymer absorbs part of the liquid electrolyte to form a solid electrolyte.
  • the initiator includes any one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptanenitrile, azoisobutylcyanoformamide, azobiscyclohexylcarbonitrile, dimethyl azobisisobutyrate, azobisisobutylamidine hydrochloride, azobisisopropylimidazoline hydrochloride and azobiscyanovaleric acid.
  • the above initiators can initiate polymerization of the polymer monomers to form a polymer, and the polymer absorbs part of the liquid electrolyte to form a solid electrolyte.
  • the present application provides a battery, which includes the battery cell in the above embodiment.
  • the present application provides an electrical device, which includes the battery cell or battery in the above-mentioned embodiment, and the battery cell or battery is used to provide electrical energy.
  • FIG1 is a schematic structural diagram of a vehicle according to some embodiments of the present application.
  • FIG2 is a schematic diagram of an exploded structure of a battery according to some embodiments of the present application.
  • FIG. 3 is a schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application.
  • the term "and/or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships.
  • a and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone.
  • the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship.
  • multiple refers to more than two (including two).
  • multiple groups refers to more than two groups (including two groups), and “multiple pieces” refers to more than two pieces (including two pieces).
  • Silicon and lithium metal have ultra-high theoretical gram capacity as anode materials, but the volume expansion rate of silicon and lithium metal has posed great challenges to their application. Batteries using silicon and lithium metal as anode materials will continue to expand and shrink during the cycle, exacerbating the extrusion of liquid electrolyte and making it impossible to reflux, resulting in a drop in the battery's cycle performance.
  • the present application comprehensively utilizes the advantages of solid electrolytes and liquid electrolytes, combines liquid electrolytes and solid electrolytes, and limits the ratio of the mass of solid electrolytes to the mass of electrolytes in battery cells with negative electrode plates having different volume expansion rates. This can not only reduce or avoid the extrusion of liquid electrolytes, but the electrolyte can also provide a better lithium ion transfer rate, so that the battery cells can take into account both cycle performance and capacity performance.
  • the battery mentioned in the embodiments of the present application refers to a single physical module including multiple battery cells to provide higher voltage and capacity.
  • the battery generally includes a battery box for packaging multiple battery cells, and the battery box can prevent liquid or other foreign matter from affecting the battery. Charging or discharging of battery cells.
  • the battery cell includes an electrode assembly and an electrolyte.
  • the electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator.
  • the battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode active material layer.
  • the positive electrode active material layer is coated on the surface of the positive electrode collector.
  • the positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer.
  • the positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab.
  • the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide.
  • the negative electrode sheet includes a negative electrode collector and a negative electrode active material layer.
  • the negative electrode active material layer is coated on the surface of the negative electrode collector.
  • the negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer.
  • the negative electrode collector not coated with the negative electrode active material layer serves as the negative electrode tab.
  • the material of the negative electrode collector can be copper. In order to ensure that a large current does not melt, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together.
  • the material of the isolation film can be polypropylene (PP) or polyethylene (PE).
  • the electrode assembly can be a winding structure or a laminated structure, and the embodiments of the present application are not limited thereto.
  • the battery cell also includes a current collecting component, which is used to electrically connect the tabs and electrode terminals of the battery cell to transmit electrical energy from the electrode assembly to the electrode terminals and then to the outside of the battery cell through the electrode terminals; multiple battery cells are electrically connected through a current collecting component to achieve series, parallel or mixed connection of multiple battery cells.
  • a current collecting component which is used to electrically connect the tabs and electrode terminals of the battery cell to transmit electrical energy from the electrode assembly to the electrode terminals and then to the outside of the battery cell through the electrode terminals; multiple battery cells are electrically connected through a current collecting component to achieve series, parallel or mixed connection of multiple battery cells.
  • the battery also includes a sampling terminal and a battery management system.
  • the sampling terminal is connected to the busbar to collect information about the battery cells, such as voltage or temperature, etc.
  • the sampling terminal transmits the collected information about the battery cells to the battery management system.
  • the battery management system detects that the information about the battery cells exceeds the normal range, it will limit the output power of the battery to achieve safety protection.
  • the electrical devices used by the batteries described in the embodiments of the present application can be in various forms, for example, mobile phones, portable devices, laptops, battery vehicles, electric cars, ships, spacecraft, electric toys and electric tools, etc.
  • spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.
  • Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.
  • Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers.
  • the battery cells and batteries described in the embodiments of the present application are not limited to the electrical devices described above, but can also be applied to all electrical devices using battery cells and batteries. However, for the sake of simplicity, the following embodiments are described using electric vehicles as examples.
  • the vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle.
  • the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.
  • a battery 100 is arranged inside the vehicle 1000, and the battery 100 can be arranged at the bottom, head or tail of the vehicle 1000.
  • the battery 100 can be used to power the vehicle 1000.
  • the battery 100 can be used as an operating power source for the vehicle 1000.
  • the vehicle 1000 may also include a controller 200 and a motor 300.
  • the controller 200 is used to control the battery 100 to power the motor 300, for example, for the starting, navigation and driving power requirements of the vehicle 1000.
  • the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.
  • FIG. 2 is an exploded view of a battery provided in some embodiments of the present application.
  • the battery 100 includes a box 10 and a battery cell 20, and the battery cell 20 is contained in the box 10.
  • the box 10 is used to provide a storage space for the battery cell 20, and the box 10 can adopt a variety of structures.
  • the box 10 may include a first part 11 and a second part 12, and the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a storage space for accommodating the battery cell 20.
  • the second part 12 can be a hollow structure with one end open, and the first part 11 can be a plate-like structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a storage space; the first part 11 and the second part 12 can also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12.
  • the box 10 formed by the first part 11 and the second part 12 can be in a variety of shapes, such as a cylinder, a cuboid, etc.
  • the battery 100 there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a mixed connection.
  • a mixed connection means that the multiple battery cells 20 are both connected in series and in parallel.
  • the multiple battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 10.
  • the battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 20.
  • Each battery cell 20 is a secondary battery, which may be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto.
  • the battery cell 20 may be cylindrical, flat, rectangular or in other shapes.
  • the end cap 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment.
  • the shape of the end cap 21 can be adapted to the shape of the shell 22 to match the shell 22.
  • the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is not easily deformed when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved.
  • Functional components such as electrode terminals can be provided on the end cap 21. The electrode terminal can be used to electrically connect to the electrode assembly 23 for outputting or inputting electrical energy of the battery cell 20.
  • the end cap 21 can also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold.
  • the material of the end cap 21 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose special restrictions on this.
  • an insulating member may be provided inside the end cap 21, and the insulating member may be used to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber, or the like.
  • the shell 22 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 22 can be determined according to the specific shape and size of the electrode assembly 23.
  • the material of the shell 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.
  • the electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur.
  • One or more electrode assemblies 23 may be included in the housing 22.
  • the electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets.
  • the parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly, and the parts of the positive and negative electrode sheets without active materials each constitute a tab.
  • the positive tab and the negative tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.
  • the present application provides a battery cell, which includes: a negative electrode plate and an electrolyte, wherein the electrolyte includes a solid electrolyte and a liquid electrolyte.
  • the ratio of the fully charged thickness of the negative electrode plate to the uncharged thickness of the negative electrode plate is x
  • the ratio of the mass of the solid electrolyte in the electrolyte to the mass of the electrolyte is y.
  • the negative electrode plate includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • a metal foil a copper foil may be used.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) It is formed on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material may adopt the negative electrode active material for the battery known in the art.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further include a binder.
  • the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • a conductive agent which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).
  • a thickener eg, sodium carboxymethyl cellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte conducts ions between the positive electrode and the negative electrode.
  • the full charge thickness of the negative electrode plate is the thickness of the negative electrode plate after the battery cell is fully charged.
  • the uncharged thickness of the negative electrode plate is the thickness of the negative electrode plate after cold pressing but before charging.
  • the mass of the electrolyte is the sum of the mass of the solid electrolyte and the mass of the liquid electrolyte.
  • the value of y can be 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48% or 50%.
  • the value of y can be 51%, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88% or 89%.
  • the value of y can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99%.
  • the battery cell of the present application is a combination of liquid electrolyte and solid electrolyte, and limits the ratio of the mass of the solid electrolyte to the mass of the electrolyte in the battery cell with negative electrode plates of different volume expansion rates. This can reduce or avoid the extrusion of the liquid electrolyte, and the electrolyte can also provide a better lithium ion transmission rate, so that the battery cell can take into account both cycle performance and capacity performance.
  • x ⁇ 20% 0 ⁇ y ⁇ 10%.
  • the volume expansion rate of the negative electrode plate When x ⁇ 20%, the volume expansion rate of the negative electrode plate is low, and 0 ⁇ y ⁇ 10% can enable the battery cell to obtain both a higher number of cycles and a larger battery capacity; when 20% ⁇ x ⁇ 80%, 70% ⁇ y ⁇ 90%, the volume expansion rate of the negative electrode plate is average, and 70% ⁇ y ⁇ 90% can enable the battery cell to take into account both the number of cycles and the battery capacity; when x ⁇ 80%, the volume expansion rate of the negative electrode plate is relatively large, and 90% ⁇ y ⁇ 93% can enable the battery cell to obtain a higher number of cycles and take into account the battery capacity.
  • the solid electrolyte is a heat-curable electrolyte.
  • the heat-curable electrolyte can be cured under heating conditions to form a solid electrolyte.
  • the curing temperature of the heat-curable electrolyte is 50°C to 110°C.
  • the curing temperature of the heat-curable electrolyte may be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, or 110°C.
  • the curing temperature of the heat-curable electrolyte is low and within the safe operating temperature range of the battery cell.
  • the curing temperature of the heat-curable electrolyte is 60°C to 70°C.
  • the liquid electrolyte includes a lithium salt and/or a sodium salt
  • the lithium salt includes any one or more of LiPF6, LiClO4, LiTFSI, LiFSI, LiBOB, LiDFOB and LiNO3.
  • the molar concentration of the lithium salt is 0.9 mol/L to 1.5 mol/L.
  • the present application also provides a method for preparing a battery cell of the above-mentioned embodiment, which includes: preparing an electrode assembly, placing the electrode assembly into a shell, injecting raw materials for forming a solid electrolyte into the shell, solidifying the raw materials for the solid electrolyte to form a solid electrolyte, and continuing to inject liquid electrolyte into the shell containing the electrode assembly, and sealing.
  • the preparation method of the battery cell of the present application is to first inject a raw material for forming a solid electrolyte into a shell containing an electrode assembly, and after the raw material for the solid electrolyte is solidified to form a solid electrolyte, a liquid electrolyte is injected into the shell containing the electrode assembly, so that a mixed electrolyte including a solid electrolyte and a liquid electrolyte can be obtained, that is, the mixing of the solid electrolyte and the liquid electrolyte is achieved by only two liquid injections, which simplifies the preparation process of the battery cell and reduces the process cost of the battery cell.
  • the method for preparing the battery cell of the present application comprises the following steps:
  • the battery cell is placed in the shell to complete the packaging, forming a hard shell battery cell without liquid injection;
  • the solid electrolyte is a heat-curable electrolyte
  • the raw materials of the heat-curable electrolyte are injected into the shell containing the electrode assembly, the raw materials of the heat-curable electrolyte are allowed to react at 50°C to 110°C for 3h to 24h to form a solid electrolyte.
  • the curing time of the heat-curable electrolyte may be 3 h, 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, or 24 h.
  • the curing process of the heat-curable electrolyte of the present application is simple and convenient, and can form a stable solid electrolyte.
  • the raw materials of the heat-curable electrolyte include a liquid electrolyte, a polymerizable monomer, and an initiator.
  • the polymerizable monomers can be polymerized to form polymers under the action of the initiator, and the polymers absorb part of the liquid electrolyte to form a solid electrolyte.
  • the mass fraction of the polymerizable monomer is 0.5 wt % to 6.5 wt %.
  • the mass fraction of the polymerized monomer can be 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt% or 6.5wt%.
  • the polymerizable monomer can be polymerized under the action of the initiator to form a high polymer, and the high polymer absorbs part of the liquid electrolyte to form a solid electrolyte, thereby obtaining an electrolyte composed of a liquid electrolyte and a solid electrolyte.
  • the mass fraction of the initiator is 0.1 wt% to 0.5 wt%.
  • the mass fraction of the initiator may be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt% or 0.5 wt%.
  • the polymerizable monomers can be polymerized under the action of the initiator to form polymers, and the polymers absorb part of the liquid electrolyte to form a solid electrolyte, thereby obtaining an electrolyte composed of a liquid electrolyte and a solid electrolyte.
  • the polymerized monomer has an unsaturated double bond.
  • the polymer monomer with unsaturated double bonds can be polymerized under the action of initiators to form polymers, which absorb part of the liquid electrolyte.
  • the solution forms a solid electrolyte.
  • the polymerizable monomers include any one or more of ester monomers, carbonate monomers, sulfone monomers, isocyanates, amide monomers, nitrile monomers and fluorinated monomers.
  • the above-mentioned polymerizable monomers can be polymerized to form high polymers under the action of an initiator, and the high polymers absorb part of the liquid electrolyte to form a solid electrolyte.
  • the polymerizable monomer includes one or two of methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, dimethylaminoethyl methacrylate, hydroxyethyl methacrylate, polyethylene glycol dimethacrylate, methylene succinic acid, maleic anhydride, acrylamide glycolic acid methyl ether, 2-methacryloyl isocyanate, N,N'bisacryloylcystamine, N,N-methylenebisacrylamide, triallyl isocyanurate and ethylene glycol dimethacrylate.
  • the initiator includes any one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptanenitrile, azoisobutylcyanoformamide, azobiscyclohexylcarbonitrile, dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, azobisisopropylimidazoline hydrochloride and azobiscyanovaleric acid.
  • the initiator can initiate polymerization of the monomers to form a polymer, and the polymer absorbs part of the liquid electrolyte to form a solid electrolyte.
  • the negative electrode silicon content is the mass percentage of the silicon-based material in the negative electrode active material layer.
  • the negative electrode silicon content the mass of the silicon oxide compound/(the mass of the artificial graphite + the mass of the silicon oxide compound).
  • the preparation method of the battery monomers of Examples 1 to 15 and Comparative Examples 1 to 10 is as follows:
  • LiFSI was dissolved in a solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1 to prepare a liquid electrolyte with a concentration of 1 mol/L, and the liquid electrolyte was divided into two parts.
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the polymerizable monomer methyl methacrylate and the initiator azobisisobutyronitrile were dissolved in a portion of liquid electrolyte at mass fractions of 5 wt % and 0.2 wt %, respectively, and mechanically stirred at 25° C. for 1 hour to obtain a raw material for forming a solid electrolyte.
  • Nickel-cobalt-manganese (NCM) ternary material, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 97:1:2, N-methylpyrrolidone is added, and the mixture is stirred for 0.5-6 hours to obtain a positive electrode slurry; the mixture is then evenly coated on a positive electrode current collector, and the positive electrode sheet is obtained after drying, cold pressing, and slitting.
  • NCM Nickel-cobalt-manganese
  • PVDF binder polyvinylidene fluoride
  • the negative electrode active material, conductive agent carbon black, binder styrene-butadiene rubber (SBR), and thickener sodium hydroxymethyl cellulose (CMC) are added into deionized water in a weight ratio of 97:0.5:1.25:1.25, and mixed and stirred for 3 hours to obtain the negative electrode slurry, which is evenly coated on the negative electrode current collector, and then dried, cold pressed, and cut to obtain the negative electrode sheet.
  • Polypropylene film is used as the isolation film.
  • the isolation film is placed between the positive electrode and the negative electrode, and the bare battery cell is obtained after winding into a core.
  • the bare battery cell is placed in an aluminum shell to obtain a hard shell battery without liquid injection.
  • the first liquid injection is injected into the raw materials for forming the solid electrolyte.
  • the battery cell is placed in a constant temperature blast oven at 70°C and heated for 12 hours to form a solid electrolyte; the second liquid injection is injected into another portion of liquid electrolyte, and the sealing nails are welded and aged at high temperature to obtain a battery cell.
  • the 80% SOH cycle number is detected by the following method:
  • the mass energy density is measured by the following method:
  • Mass energy density (Wh/kg) discharge capacity (Wh)/battery cell mass (kg).
  • the 80% SOH cycle number of the battery cell is 2500cls ⁇ 2620cls, and the mass energy density is 230Wh/kg ⁇ 240Wh/kg;
  • the ratio x of the fully charged thickness of the negative electrode plate to the uncharged thickness of the negative electrode plate is 28, the negative active material of the negative electrode plate is a mixture of graphite and silicon-based materials, and the silicon content in the negative active material is 5wt%.
  • the ratio x of the fully charged thickness of the negative electrode plate to the uncharged thickness of the negative electrode plate is 68
  • the negative active material of the negative electrode plate is a mixture of graphite and silicon-based materials
  • the silicon content in the negative active material is 30wt%.
  • the ratio x of the full-charge thickness of the negative electrode sheet to the uncharged thickness of the negative electrode sheet is 80
  • the negative electrode active material of the negative electrode sheet is a mixture of graphite and silicon-based materials
  • the silicon content in the negative electrode active material is 55wt%.
  • the 80% SOH cycle number of the battery cell is 780cls to 820cls, and the mass energy density is 324Wh/kg to 326Wh/kg;
  • the ratio x of the full-charge thickness of the negative electrode sheet to the uncharged thickness of the negative electrode sheet is 90
  • the negative electrode active material of the negative electrode sheet is a mixture of graphite and silicon-based materials
  • the silicon content in the negative electrode active material is 60wt%.
  • the 80% SOH cycle number of the battery cell is 700cls ⁇ 730cls, and the mass energy density is 332Wh/kg ⁇ 335Wh/kg;

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Abstract

本申请提供一种电池单体及其制备方法、电池及用电装置，属于电池技术领域。电池单体包括负极极片和电解质，电解质包括固态电解质和液态电解质。负极极片满充厚度与负极极片未充电厚度的比值为x，电解质中固态电解质的质量与电解质的质量的比值为y。当x≤20％时，0＜y≤50％。当20％＜x＜80％时，50％＜y＜90％。当x≥80％时，90％≤y≤96％。本申请的电池单体以液态电解质和固态电解质配合，并限定具有不同体积膨胀率的负极极片的电池单体中固态电解质的质量与电解质的质量的比值，既能够减少或避免液态电解质的挤出，电解质还能够提供较好的锂离子传输速率，使得电池单体能够兼顾循环性能和容量性能。

Description

一种电池单体及其制备方法、电池及用电装置 技术领域
本申请涉及电池技术领域，具体而言，涉及一种电池单体及其制备方法、电池及用电装置。
背景技术
随着锂电的发展，行业和市场对能量密度有了更高的需求。硅和锂金属作为阳极材料有超高的理论克容量，但硅和锂金属的体积膨胀率问题使其应用受到了巨大挑战。采用硅和锂金属作为阳极材料的电池在循环中阳极会不断膨胀收缩，加剧液态电解质挤出无法回流，导致电池的循环性能跳水。
发明内容
鉴于上述问题，本申请提供一种电池单体及其制备方法、电池及用电装置，能够使得电池能够兼顾循环性能和容量性能。
第一方面，本申请提供了一种电池单体，其包括：负极极片和电解质，电解质包括固态电解质和液态电解质。负极极片满充厚度与负极极片未充电厚度的比值为x，电解质中固态电解质的质量与电解质的质量的比值为y。当x≤20％时，0＜y≤50％。当20％＜x＜80％时，50％＜y＜90％。当x≥80％时，90％≤y≤96％。
本申请实施例的技术方案中，本申请的电池单体以液态电解质和固态电解质配合，并限定具有不同体积膨胀率的负极极片的电池单体中固态电解质的质量与电解质的质量的比值，既能够减少或避免液态电解质的挤出，电解质还能够提供较好的锂离子传输速率，使得电池单体能够兼顾循环性能和容量性能。
在一些实施例中，当x≤20％时，0＜y≤10％。当20％＜x＜80％时，70％≤y＜90％。当x≥80％时，90％≤y≤93％。当x≤20％时，负极极片的体积膨胀率较低，0＜y≤10％能够使得电池单体同时获得较高的循环圈数和较大的电池容量；当20％＜x＜80％时，70％≤y＜90％时，负极极片的体积膨胀率一般，70％≤y＜90％能够使得电池单体兼顾循环圈数和电池容量；当x≥80％时，负极极片的体积膨胀率较大，90％≤y≤93％能够使得电池单体获得较高的循环圈数且兼顾电池容量。
在一些实施例中，固态电解质为可加热固化电解质。可加热固化电解质可以在加热的条件下固化形成为固态电解质。
在一些实施例中，可加热固化电解质的固化温度为50℃～110℃。可加热固化电解质的固化温度较低，且在电池单体的安全使用温度范围内。
在一些实施例中，液态电解质包括锂盐和/或钠盐，锂盐包括LiPF6、LiClO4、LiTFSI、LiFSI、LiBOB、LiDFOB和LiNO3中的任意一种或多种。
第二方面，本申请提供了一种上述实施例的电池单体的制备方法，其包括：制备电极组件。将电极组件放入壳体，向壳体中注入形成固态电解质的原料，使固态电解质的原料固化形成固态电解质，继续向装有电极组件的壳体中注入液态电解质，密封。
本申请实施例的技术方案中，本申请的电池单体的制备方法通过先向装有电极组件的壳体中注入形成固态电解质的原料，并且使固态电解质的原料固化形成固态电解质后，再向装有电极组件的壳体中注入液态电解质，能够得到包括固态电解质和液态电解质的混合电解质，即仅通过两次注液实现固态电解质和液态电解质的混合，简化了电池单体的制备流程，减少了电池单体的工艺成本。
在一些实施例中，固态电解质为可加热固化电解质，向装有电极组件的壳体中注入可加热 固化电解质的原料后，使得可加热固化电解质的原料在50℃～110℃下反应3h～24h形成固态电解质。本申请的可加热固化电解质的固化工艺简便，且能够形成稳定的固态电解质。
在一些实施例中，可加热固化电解质的原料包括液态电解质、聚合单体和引发剂。在加热条件下，聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质。
在一些实施例中，在原料中，聚合单体的质量分数为0.5wt％～6.5wt％。当在原料中，聚合单体的质量分数为0.5wt％～6.5wt％时，聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质，从而得到液态电解质和固态电解质配合的电解质。
在一些实施例中，在原料中，引发剂的质量分数为0.1wt％～0.5wt％。当在原料中，引发剂的质量分数为0.1wt％～0.5wt％时，聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质，从而得到液态电解质和固态电解质配合的电解质。
在一些实施例中，聚合单体具有不饱和双键。具有不饱和双键的聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质。
在一些实施例中，聚合单体包括酯类单体、碳酸酯类单体、砜类单体、异氰酸酯类、酰胺类单体、腈类单体和氟化类单体中的任意一种或多种。上述聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质。
在一些实施例中，引发剂包括偶氮二异丁腈、偶氮二异戊腈、偶氮二异庚腈、偶氮异丁氰基甲酰胺、偶氮二环己基甲腈、偶氮二异丁酸二甲酯、偶氮二异丁脒盐酸盐、偶氮二异丙基咪唑啉盐酸盐和偶氮二氰基戊酸中的任意一种或多种。上述引发剂能够引发聚合单体聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质。
第三方面，本申请提供了一种电池，其包括上述实施例中的电池单体。
第四方面，本申请提供了一种用电装置，其包括上述实施例中的电池单体或电池，电池单体或电池用于提供电能。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
通过阅读对下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。而且在全部附图中，用相同的附图标号表示相同的部件。在附图中：
图1为本申请一些实施例的车辆的结构示意图；
图2为本申请一些实施例的电池的分解结构示意图；
图3为本申请一些实施例的电池单体的分解结构示意图。
具体实施方式中的附图标号如下：
1000-车辆；100-电池；200-控制器；300-马达；
10-箱体；11-第一部分；12-第二部分；
20-电池单体；21-端盖；22-壳体；23-电极组件。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚 地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本文中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中，“多个”的含义是两个以上，除非另有明确具体的限定。
在本文中提及“实施例”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该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，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，术语“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
在本申请实施例的描述中，技术术语“中心”“纵向”“横向”“长度”“宽度”“厚度”“上”“下”“前”“后”“左”“右”“竖直”“水平”“顶”“底”“内”“外”“顺时针”“逆时针”“轴向”“径向”“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请实施例的限制。
在本申请实施例的描述中，除非另有明确的规定和限定，技术术语“安装”“相连”“连接”“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请实施例中的具体含义。
目前，从市场形势的发展来看，动力电池的应用越加广泛。动力电池不仅被应用于水力、火力、风力和太阳能电站等储能电源系统，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。随着动力电池应用领域的不断扩大，其市场的需求量也在不断地扩增。
随着锂电的发展，行业和市场对能量密度有了更高的需求。硅和锂金属作为阳极材料有超高的理论克容量，但硅和锂金属的体积膨胀率问题使其应用受到了巨大挑战。采用硅和锂金属作为阳极材料的电池在循环中阳极会不断膨胀收缩，加剧液态电解质挤出无法回流，导致电池的循环性能跳水。
固态电解质的热力学和电化学稳定性、机械强度普遍比液态电解质好。固态电解质的离子传导也更稳定，离子沉积更为稳定，使锂离子电池能够更稳定地循环。固态电解质还有锁液作用，在高膨胀体系内能避免液态电解质的挤出。液态电解质离子电导率高，在电池中回流浸润效果好，但安全性低。
基于以上考虑，为了提高电池单体的性能，本申请综合利用固态电解质和液态电解质的优势，以液态电解质和固态电解质配合，并限定具有不同体积膨胀率的负极极片的电池单体中固态电解质的质量与电解质的质量的比值，既能够减少或避免液态电解质的挤出，电解质还能够提供较好的锂离子传输速率，使得电池单体能够兼顾循环性能和容量性能。
本申请的实施例所提到的电池是指包括多个电池单体以提供更高的电压和容量的单一的物理模块。电池一般包括用于封装多个电池单体的电池箱体，电池箱体可以避免液体或其他异物影响 电池单体的充电或放电。
其中，每个电池单体为二次电池；可以是锂离子电池，还可以是锂硫电池，但不局限于此。电池单体可呈圆柱体、扁平体、长方体或其它形状等。电池单体一般按封装的方式分成三种：圆柱电池单体、方形电池单体和软包电池单体。
电池单体包括电极组件和电解质，电极组件由正极极片、负极极片和隔离膜组成。电池单体主要依靠金属离子在正极极片和负极极片之间移动来工作。正极极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面，未涂覆正极活性物质层的正极集流体凸出于已涂覆正极活性物质层的正极集流体，未涂覆正极活性物质层的正极集流体作为正极极耳。以锂离子电池为例，正极集流体的材料可以为铝，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等。负极极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面，未涂覆负极活性物质层的负极集流体凸出于已涂覆负极活性物质层的负极集流体，未涂覆负极活性物质层的负极集流体作负极极耳。负极集流体的材料可以为铜。为了保证通过大电流而不发生熔断，正极极耳的数量为多个且层叠在一起，负极极耳的数量为多个且层叠在一起。隔离膜的材质可以为聚丙烯(Polypropylene，PP)或聚乙烯(Polyethylene，PE)等。此外，电极组件可以是卷绕式结构，也可以是叠片式结构，本申请实施例并不限于此。
电池单体还包括集流构件，集流构件用于将电池单体的极耳和电极端子电连接，以将电能从电极组件输送至电极端子，经电极端子输送至电池单体的外部；多个电池单体之间通过汇流部件实现电连接，以实现多个电池单体的串联、并联或者混联。
电池还包括采样端子和电池管理系统，采样端子连接于汇流部件，用于采集电池单体的信息，例如电压或者温度等等。采样端子将所采集到的电池单体的信息传递至电池管理系统，电池管理系统检测到电池单体的信息超出正常范围时，会限制电池的输出功率以实现安全防护。
可以理解的是，本申请实施例中描述的使用电池所适用的用电装置可以为多种形式，例如，手机、便携式设备、笔记本电脑、电瓶车、电动汽车、轮船、航天器、电动玩具和电动工具等等，例如，航天器包括飞机、火箭、航天飞机和宇宙飞船等等，电动玩具包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等，电动工具包括金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨。
本申请的实施例描述的电池单体以及电池不仅仅局限适用于上述所描述的用电装置，还可以适用于所有使用电池单体以及电池的用电装置，但为描述简洁，下述实施例均以电动汽车为例进行说明。
请参阅图1，图1为本申请一些实施例提供的车辆的结构示意图。车辆1000可以为燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1000的内部设置有电池100，电池100可以设置在车辆1000的底部或头部或尾部。电池100可以用于车辆1000的供电，例如，电池100可以作为车辆1000的操作电源。车辆1000还可以包括控制器200和马达300，控制器200用来控制电池100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池100不仅仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参照图2，图2为本申请一些实施例提供的电池的爆炸图。电池100包括箱体10和电池单体20，电池单体20容纳于箱体10内。其中，箱体10用于为电池单体20提供容纳空间，箱体10可以采用多种结构。在一些实施例中，箱体10可以包括第一部分11和第二部分12，第一部分11与第二部分12相互盖合，第一部分11和第二部分12共同限定出用于容纳电池单体20的容纳空间。第二部分12可以为一端开口的空心结构，第一部分11可以为板状结构，第一部分11盖合于第二部分12的开口侧，以使第一部分11与第二部分12共同限定出容纳空间；第一部分11和第二部分12也可以是均为一侧开口的空心结构，第一部分11的开口侧盖合于第二部分12的开口侧。当然，第一部分11和第二部分12形成的箱体10可以是多种形状，比如，圆柱体、长方体等。
在电池100中，电池单体20可以是多个，多个电池单体20之间可串联或并联或混联，混联是指多个电池单体20中既有串联又有并联。多个电池单体20之间可直接串联或并联或混联在一起，再将多个电池单体20构成的整体容纳于箱体10内；当然，电池100也可以是多个电池单体20先串联或并联或混联组成电池模块形式，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体10内。电池100还可以包括其他结构，例如，该电池100还可以包括汇流部件，用于实现多个电池单体20之间的电连接。
其中，每个电池单体20为二次电池；可以是锂离子电池，还可以是锂硫电池、钠离子电池或镁离子电池，但不局限于此。电池单体20可呈圆柱体、扁平体、长方体或其它形状等。
请参照图3，图3为本申请一些实施例提供的第一种电池单体的分解结构示意图。电池单体20是指组成电池的最小单元。如图3，电池单体20包括有端盖21、壳体22、电极组件23以及其他的功能性部件。
端盖21是指盖合于壳体22的开口处以将电池单体20的内部环境隔绝于外部环境的部件。不限地，端盖21的形状可以与壳体22的形状相适应以配合壳体22。可选地，端盖21可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖21在受挤压碰撞时就不易发生形变，使电池单体20能够具备更高的结构强度，安全性能也可以有所提高。端盖21上可以设置有如电极端子等的功能性部件。电极端子可以用于与电极组件23电连接，以用于输出或输入电池单体20的电能。在一些实施例中，端盖21上还可以设置有用于在电池单体20的内部压力或温度达到阈值时泄放内部压力的泄压机构。端盖21的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖21的内侧还可以设置有绝缘件，绝缘件可以用于隔离壳体22内的电连接部件与端盖21，以降低短路的风险。示例性的，绝缘件可以是塑料、橡胶等。
壳体22是用于配合端盖21以形成电池单体20的内部环境的组件，其中，形成的内部环境可以用于容纳电极组件23、电解质以及其他部件。壳体22和端盖21可以是独立的部件，可以于壳体22上设置开口，通过在开口处使端盖21盖合开口以形成电池单体20的内部环境。不限地，也可以使端盖21和壳体22一体化，具体地，端盖21和壳体22可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体22的内部时，再使端盖21盖合壳体22。壳体22可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体22的形状可以根据电极组件23的具体形状和尺寸大小来确定。壳体22的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
电极组件23是电池单体20中发生电化学反应的部件。壳体22内可以包含一个或更多个电极组件23。电极组件23主要由正极片和负极片卷绕或层叠放置形成，并且通常在正极片与负极片之间设有隔膜。正极片和负极片具有活性物质的部分构成电极组件的主体部，正极片和负极片不具有活性物质的部分各自构成极耳。正极极耳和负极极耳可以共同位于主体部的一端或是分别位于主体部的两端。在电池的充放电过程中，正极活性物质和负极活性物质与电解质发生反应，极耳连接电极端子以形成电流回路。
根据本申请的一些实施例，本申请提供了一种电池单体，其包括：负极极片和电解质，电解质包括固态电解质和液态电解质。负极极片满充厚度与负极极片未充电厚度的比值为x，电解质中固态电解质的质量与电解质的质量的比值为y。当x≤20％时，0＜y≤50％。当20％＜x＜80％时，50％＜y＜90％。当x≥80％时，90％≤y≤96％。
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，负极膜层包括负极活性物质。
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，负极膜层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)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性物质可采用本领域公知的用于电池的负极活性物质。作为示例，负极活性物质可包括以下材料中的至少一种：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。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至少一种。锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性物质的传统材料。这些负极活性物质可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极膜层还可选地包括粘结剂。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)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。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至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性物质、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
电解质在正极极片和负极极片之间起到传导离子的作用。
负极极片满充厚度为电池单体满充后的负极极片的厚度。
负极极片未充电厚度为负极极片冷压后还未进行充电的厚度。
电解质的质量为固态电解质的质量和液态电解质的质量之和。
作为示例，当x≤20％时，y的值可以为1％、2％、5％、8％、10％、12％、15％、18％、20％、22％、25％、28％、30％、32％、35％、38％、40％、42％、45％、48％或50％。
当20％＜x＜80％时，y的值可以为51％、52％、55％、58％、60％、62％、65％、68％、70％、72％、75％、78％、80％、82％、85％、88％或89％。
当x≥80％时，y的值可以为90％、91％、92％、93％、94％、95％、96％、97％、98％或99％。
本申请的电池单体以液态电解质和固态电解质配合，并限定具有不同体积膨胀率的负极极片的电池单体中固态电解质的质量与电解质的质量的比值，既能够减少或避免液态电解质的挤出，电解质还能够提供较好的锂离子传输速率，使得电池单体能够兼顾循环性能和容量性能。
根据本申请的一些实施例，可选地，当x≤20％时，0＜y≤10％。当20％＜x＜80％时，70％≤y＜90％。当x≥80％时，90％≤y≤93％。
当x≤20％时，负极极片的体积膨胀率较低，0＜y≤10％能够使得电池单体同时获得较高的循环圈数和较大的电池容量；当20％＜x＜80％时，70％≤y＜90％时，负极极片的体积膨胀率一般，70％≤y＜90％能够使得电池单体兼顾循环圈数和电池容量；当x≥80％时，负极极片的体积膨胀率较大，90％≤y≤93％能够使得电池单体获得较高的循环圈数且兼顾电池容量。
根据本申请的一些实施例，可选地，固态电解质为可加热固化电解质。
可加热固化电解质可以在加热的条件下固化形成为固态电解质。
根据本申请的一些实施例，可选地，可加热固化电解质的固化温度为50℃～110℃。
作为示例，可加热固化电解质的固化温度可以为50℃、55℃、60℃、65℃、70℃、75℃、80℃、85℃、90℃、95℃、100℃、105℃或110℃。
可加热固化电解质的固化温度较低，且在电池单体的安全使用温度范围内。
可选地，可加热固化电解质的固化温度为60℃～70℃。
根据本申请的一些实施例，可选地，液态电解质包括锂盐和/或钠盐，锂盐包括LiPF6、LiClO4、LiTFSI、LiFSI、LiBOB、LiDFOB和LiNO3中的任意一种或多种。
可选地，锂盐的摩尔浓度为0.9mol/L～1.5mol/L。
根据本申请的一些实施例，本申请还提供一种上述实施例的电池单体的制备方法，其包括：制备电极组件，将电极组件放入壳体，向壳体中注入形成固态电解质的原料，使固态电解质的原料固化形成固态电解质，继续向装有电极组件的壳体中注入液态电解质，密封。
本申请的电池单体的制备方法通过先向装有电极组件的壳体中注入形成固态电解质的原料，并且使固态电解质的原料固化形成固态电解质后，再向装有电极组件的壳体中注入液态电解质，能够得到包括固态电解质和液态电解质的混合电解质，即仅通过两次注液实现固态电解质和液态电解质的混合，简化了电池单体的制备流程，减少了电池单体的工艺成本。
具体的，本申请的电池单体的制备方法包括以下步骤：
S1：将正极极片、负极极片和隔离膜装配在一起，并卷绕成芯后得到电芯；
S2：将电芯装入壳体内完成封装，形成未注液的硬壳电芯；
S3：将形成固态电解质的原料注入电芯内，注液口不塞上密封钉，敞口固化；
S4：拔掉密封钉，将液态电解质注入电芯，密封钉焊接，制得电池单体。
根据本申请的一些实施例，可选地，固态电解质为可加热固化电解质，向装有电极组件的壳体中注入可加热固化电解质的原料后，使得可加热固化电解质的原料在50℃～110℃下反应3h～24h形成固态电解质。
作为示例，可加热固化电解质的固化时间可以为3h、5h、8h、10h、12h、15h、18h、20h、22h或24h。
本申请的可加热固化电解质的固化工艺简便，且能够形成稳定的固态电解质。
根据本申请的一些实施例，可选地，可加热固化电解质的原料包括液态电解质、聚合单体和引发剂。
在加热条件下，聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质。
根据本申请的一些实施例，可选地，在原料中，聚合单体的质量分数为0.5wt％～6.5wt％。
作为示例，聚合单体的质量分数可以为0.5wt％、1wt％、1.5wt％、2wt％、2.5wt％、3wt％、3.5wt％、4wt％、4.5wt％、5wt％、5.5wt％、6wt％或6.5wt％。
当在原料中，聚合单体的质量分数为0.5wt％～6.5wt％时，聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质，从而得到液态电解质和固态电解质配合的电解质。
根据本申请的一些实施例，可选地，在原料中，引发剂的质量分数为0.1wt％～0.5wt％。
作为示例，引发剂的质量分数可以为0.1wt％、0.2wt％、0.3wt％、0.4wt％或0.5wt％。
当在原料中，引发剂的质量分数为0.1wt％～0.5wt％时，聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质，从而得到液态电解质和固态电解质配合的电解质。
根据本申请的一些实施例，可选地，聚合单体具有不饱和双键。
具有不饱和双键的聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电 解质形成固态电解质。
根据本申请的一些实施例，可选地，聚合单体包括酯类单体、碳酸酯类单体、砜类单体、异氰酸酯类、酰胺类单体、腈类单体和氟化类单体中的任意一种或多种。
上述聚合单体能够在引发剂作用下聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质。
可选地，聚合单体包括甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丙酯、甲基丙烯酸丁酯、甲基丙烯酸二甲氨基乙酯、甲基丙烯酸羟基乙酯、聚乙二醇二甲基丙烯酸酯、亚甲基丁二酸、顺丁烯二酸酐、丙烯酰胺乙醇酸甲酯甲基醚、2甲基丙烯酰异氰酸氧乙酯、N,N'双丙烯酰胱胺、N,N亚甲基双丙烯酰胺、三烯丙基异三聚氰酸酯和乙二醇二甲基丙烯酸酯中的一种或两种。
根据本申请的一些实施例，可选地，引发剂包括偶氮二异丁腈、偶氮二异戊腈、偶氮二异庚腈、偶氮异丁氰基甲酰胺、偶氮二环己基甲腈、偶氮二异丁酸二甲酯、偶氮二异丁脒盐酸盐、偶氮二异丙基咪唑啉盐酸盐和偶氮二氰基戊酸中的任意一种或多种。
上述引发剂能够引发聚合单体聚合形成高聚物，高聚物吸收部分液态电解质形成固态电解质。
以下结合实施例对本申请的一种电池单体及其制备方法、电池及用电装置作进一步的详细描述。
本申请实施例1～15和对比例1～10的电池单体的参数如表1所示。
表1实施例1～15和对比例1～10的电池单体的参数
负极硅含量为负极活性物质层中硅基材料的质量百分数，例如在实施例7中，负极硅含量＝硅氧化合物质量/(人造石墨质量+硅氧化合物质量)。
采用实施例1～15和对比例1～10电池单体的制备方法如下：
S1、制备液态电解质
将LiFSI溶于碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比1：1：1的溶剂中，配置成浓度为1mol/L的液态电解质，并将液态电解质分成两份。
S2、制备固态电解质
将聚合单体甲基丙烯酸甲酯和引发剂偶氮二异丁腈分别以质量分数5wt％、0.2wt％溶解在一份液态电解质中，于25℃机械搅拌1h，得到形成固态电解质的原料。
S3、制备正极极片
将镍钴锰(NCM)三元材料、导电剂碳黑、粘结剂聚偏二氟乙烯(PVDF)按质量比为97：1：2混合，加入N-甲基吡咯烷酮，混合搅拌0.5-6h，得到正极浆料；之后将其均匀涂覆于正极集流体上，经烘干、冷压、分切，得到正极极片。
S4、制备负极极片
将负极活性物质、导电剂碳黑、粘结剂丁苯橡胶(SBR)、增稠剂羟甲基纤维素钠(CMC)按照重量比为97：0.5：1.25：1.25，加入去离子水中，混合搅拌3h，得到负极浆料，将其均匀涂覆在负极集流体上，经烘干、冷压、分切，得到负极极片。
S5、选择隔离膜
以聚丙烯膜作为隔离膜。
S6、制备电池单体
按照常规锂电池组装工艺将隔离膜置于正极极片和负极极片之间，卷绕成芯后得到裸电芯，将裸电芯置于铝壳中，得到未注液的硬壳电池。电芯干燥后第一次注液，注入形成固态电解质的原料，待电解质充分浸润后化成，化成后将电芯置于70℃的恒温鼓风烘箱中加热12h，形成固态电解质；第二次注液注入另一份液态电解质，密封钉焊接后高温老化，得到电池单体。
试验例1
分别测得实施例1～15和对比例1～10的电池单体的循环性能和质量能量密度，结果如表2所示。
其中，80％SOH循环圈数通过以下方法检测：
将电池单体置于恒温环境中，程序设置：静置10min，以0.33C电流充电至4.25V，然后恒压充电至电流下降至0.05C，跳转至下一步，静置10min，然后以0.33C电流放电至2.5V，此为一个充放电循环过程，此次的放电容量为首次循环的放电容量。将电池单体按上述方法进行一定次数的循环充放电测试，直至放电容量为首次循环的放电容量的80％，记录电池单体的充放电循环圈数。
质量能量密度通过以下方法测得：
在25℃下以0.33C标准充电到4.25V，4.25V恒压充电至0.05C，静置10min后，0.33C放电至2.5V，记录其放电容量，随后计算放电时的质量能量密度：
质量能量密度(Wh/kg)＝放电容量(Wh)/电池单体质量(kg)。
表2实施例1～15和对比例1～10的电池单体的性能
由实施例1～3可知，负极极片满充厚度与负极极片未充电厚度的比值x为19，负极极片的负极活性物质为石墨，且负极活性物质中硅含量为0。当电解质中固态电解质的质量与电解质的质量的比值y满足0＜y≤50％时，电池单体的80％SOH循环圈数为2500cls～2620cls，质量能量密度为230Wh/kg～240Wh/kg；由实施例1～3和对比例1～2对比可知，当电解质中固态电解质的质量与电解质的质量的比值y满足y＞50％时，电池单体的80％SOH循环圈数仅为900cls～1200cls，即电池单体发生跳水，负极极片的体积膨胀率较低时，不需要过多的固态电解质锁液，而过多的固态电解质只会增大极化。
由实施例4～6可知，负极极片满充厚度与负极极片未充电厚度的比值x为28，负极极片的负极活性物质为石墨和硅基材料的混合物，且负极活性物质中硅含量为5wt％。当电解质中固态电解质的质量与电解质的质量的比值y满足50％＜y＜90％时，电池单体的80％SOH循环圈数为1700cls～1750cls，质量能量密度为255Wh/kg～260Wh/kg；由实施例4～6和对比例3对比可知，当电解质中固态电解质的质量与电解质的质量的比值y满足y≤50％时，电池单体的80％SOH循环圈数仅为1550cls，即固态电解质的量较少，负极极片的体积膨胀导致挤出的液态电解质较多，有循环跳水风险；由实施例4～6和对比例4对比可知，当电解质中固态电解质的质量与电解质的质量的比值y满足y≥90％时，电池单体的质量能量密度仅为240Wh/kg，过多的固态电解质会影响到锂离子传输速率。
由实施例7～9可知，负极极片满充厚度与负极极片未充电厚度的比值x为68，负极极片的负极活性物质为石墨和硅基材料的混合物，且负极活性物质中硅含量为30wt％。当电解质中固态电解质的质量与电解质的质量的比值y满足50％＜y＜90％时，电池单体的80％SOH循环圈数为1200cls～1260cls，质量能量密度为296Wh/kg～302Wh/kg；由实施例7～9和对比例5对比可知，当电解质中固态电解质的质量与电解质的质量的比值y满足y≤50％时，电池单体的80％SOH循环圈数仅为1050cls，即固态电解质的量较少，负极极片的体积膨胀导致挤出的液态电解质较多，有循环跳水风险；由实施例7～9和对比例6对比可知，当电解质中固态电解质的质量与电解质的质量的比值y满足y≥90％时，电池单体的质量能量密度仅为280Wh/kg，过多的固态电解质会影响到锂离子传输速率。
由实施例10～12可知，负极极片满充厚度与负极极片未充电厚度的比值x为80，负极极片的负极活性物质为石墨和硅基材料的混合物，且负极活性物质中硅含量为55wt％。当电解质中固态电解质的质量与电解质的质量的比值y满足90％≤y≤96％时，电池单体的80％SOH循环圈数为780cls～820cls，质量能量密度为324Wh/kg～326Wh/kg；由实施例10～12和对比例7～8对比可知，当电解质中固态电解质的质量与电解质的质量的比值y满足y＜90％时，电池单体的80％SOH循环圈数仅为700cls，即固态电解质的量较少，负极极片的体积膨胀导致挤出的液态电解质较多。
由实施例13～15可知，负极极片满充厚度与负极极片未充电厚度的比值x为90，负极极片的负极活性物质为石墨和硅基材料的混合物，且负极活性物质中硅含量为60wt％。当电解质中固态电解质的质量与电解质的质量的比值y满足90％≤y≤96％时，电池单体的80％SOH循环圈数为700cls～730cls，质量能量密度为332Wh/kg～335Wh/kg；由实施例13～15和对比例9～10对比可知，当电解质中固态电解质的质量与电解质的质量的比值y满足y＜90％时，电池单体的80％SOH循环圈数仅为600cls～620cls，即固态电解质的量较少，负极极片的体积膨胀导致挤出的液态电解质较多。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围，其均应涵盖在本申请的权利要求和说明书的范围当中。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (15)

  1. 一种电池单体，其中，所述电池单体包括：负极极片和电解质，所述电解质包括固态电解质和液态电解质；
    所述负极极片满充厚度与所述负极极片未充电厚度的比值为x，所述电解质中固态电解质的质量与所述电解质的质量的比值为y；
    当x≤20％时，0＜y≤50％；
    当20％＜x＜80％时，50％＜y＜90％；
    当x≥80％时，90％≤y≤96％。
  2. 根据权利要求1所述的电池单体，其中，当x≤20％时，0＜y≤10％；
    当20％＜x＜80％时，70％≤y＜90％；
    当x≥80％时，90％≤y≤93％。
  3. 根据权利要求1或2所述的电池单体，其中，所述固态电解质为可加热固化电解质。
  4. 根据权利要求3所述的电池单体，其中，所述可加热固化电解质的固化温度为50℃～110℃。
  5. 根据权利要求1～4任一项所述的电池单体，其中，所述液态电解质包括锂盐和/或钠盐，所述锂盐包括LiPF6、LiClO4、LiTFSI、LiFSI、LiBOB、LiDFOB和LiNO3中的任意一种或多种。
  6. 一种根据权利要求1～5任一项所述的电池单体的制备方法，其中，所述电池单体的制备方法包括：
    制备电极组件；
    将所述电极组件放入壳体，向所述壳体中注入形成所述固态电解质的原料，使所述固态电解质的原料固化形成所述固态电解质，继续向装有所述电极组件的壳体中注入所述液态电解质，密封。
  7. 根据权利要求6所述的电池单体的制备方法，其中，所述固态电解质为可加热固化电解质，向装有电极组件的壳体中注入所述可加热固化电解质的原料后，使得所述可加热固化电解质的原料在50℃～110℃下反应3h～24h形成所述固态电解质。
  8. 根据权利要求7所述的电池单体的制备方法，其中，所述可加热固化电解质的原料包括液态电解质、聚合单体和引发剂。
  9. 根据权利要求8所述的电池单体的制备方法，其中，在所述原料中，所述聚合单体的质量分数为0.5wt％～6.5wt％。
  10. 根据权利要求8或9所述的电池单体的制备方法，其中，在所述原料中，所述引发剂的质量分数为0.1wt％～0.5wt％。
  11. 根据权利要求8～10任一项所述的电池单体的制备方法，其中，所述聚合单体具有不饱和双键。
  12. 根据权利要求8～11任一项所述的电池单体的制备方法，其中，所述聚合单体包括酯类单体、碳酸酯类单体、砜类单体、异氰酸酯类、酰胺类单体、腈类单体和氟化类单体中的任意一种或多种。
  13. 根据权利要求8～12任一项所述的电池单体，其中，所述引发剂包括偶氮二异丁腈、偶氮二异戊腈、偶氮二异庚腈、偶氮异丁氰基甲酰胺、偶氮二环己基甲腈、偶氮二异丁酸二甲酯、偶氮二异丁脒盐酸盐、偶氮二异丙基咪唑啉盐酸盐和偶氮二氰基戊酸中的任意一种或多种。
  14. 一种电池，其中，所述电池包括如权利要求1～5任一项所述的电池单体。
  15. 一种用电装置，其中，所述用电装置包括如权利要求1～5所述的电池单体或权利要求14所述的电池，所述电池单体或所述电池用于提供电能。
PCT/CN2023/095339 2023-05-19 2023-05-19 一种电池单体及其制备方法、电池及用电装置 Ceased WO2024239155A1 (zh)

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