WO2022226748A1 - 电池组、电池包、用电装置以及电池组的制造方法及制造设备 - Google Patents

电池组、电池包、用电装置以及电池组的制造方法及制造设备 Download PDF

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WO2022226748A1
WO2022226748A1 PCT/CN2021/090067 CN2021090067W WO2022226748A1 WO 2022226748 A1 WO2022226748 A1 WO 2022226748A1 CN 2021090067 W CN2021090067 W CN 2021090067W WO 2022226748 A1 WO2022226748 A1 WO 2022226748A1
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Prior art keywords
cell
battery
battery pack
type
isolation film
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PCT/CN2021/090067
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English (en)
French (fr)
Inventor
刘倩
叶永煌
梁成都
金海族
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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 PCT/CN2021/090067 priority Critical patent/WO2022226748A1/zh
Priority to EP21856897.0A priority patent/EP4113685A4/en
Priority to CN202180004800.9A priority patent/CN115529847A/zh
Priority to US17/890,302 priority patent/US11804637B2/en
Publication of WO2022226748A1 publication Critical patent/WO2022226748A1/zh

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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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/509—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the type of connection, e.g. mixed connections
    • H01M50/51—Connection only in series
    • 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
    • H01M16/00—Structural combinations of different types of electrochemical generators
    • 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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • 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
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H01M50/434—Ceramics
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • 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
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • 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
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/267—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders having means for adapting to batteries or cells of different types or different sizes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of energy storage devices, and in particular, to a battery pack, a battery pack, an electrical device, a battery pack manufacturing method, and a battery pack manufacturing device.
  • Secondary battery is a clean and renewable resource, which can be used as driving energy or storage unit in automobile, energy storage and other fields. With the improvement of energy and environmental protection requirements, the application of secondary batteries has become increasingly popular and widespread. In order to meet the needs of different environments and application scenarios, the industry puts forward new requirements for the performance of secondary batteries.
  • a technical solution is proposed to form a battery group by connecting a plurality of single cells of different chemical systems in series and/or in parallel.
  • their kinetic properties are significantly different.
  • the rate performance and power performance of the battery pack are often affected by the short-board effect. Limited to single cells with poor dynamic characteristics, it is difficult for some cells in the battery pack to give full play to their electrical performance advantages.
  • the present application is made in view of the above problems in the prior art, and its purpose is to provide a battery pack, which includes a first type of battery cell and a second type of battery cell with different chemical systems, the first type of battery cell and The cells of the second type are electrically connected at least in series.
  • a number of parameters of the respective separators of the first type of cells and the second type of cells comprehensive optimization from the substrate to the coating, from the bulk to the surface, from the pore structure to the interface contact, etc.
  • the rate performance and power performance of the battery pack are improved.
  • a first aspect of the present application provides a battery pack, comprising at least first type cells and second type cells electrically connected in series, wherein the first type cells and the second type cells are of different chemistries
  • the first cell and the second cell satisfy: 0.1 ⁇ x1/x2 ⁇ 100.
  • the first cell and the second cell satisfy: 0.3 ⁇ x1 ⁇ 95, and/or, 0.2 ⁇ x2 ⁇ 55.
  • the average thickness t1 of the first isolation film and the average thickness t2 of the second isolation film satisfy: 4 ⁇ m ⁇ t1 ⁇ 20 ⁇ m, and/or, 8 ⁇ m ⁇ t2 ⁇ 16 ⁇ m.
  • the average pore size r1 of the first isolation film and the average pore size r2 of the second isolation film satisfy: 0.01 ⁇ m ⁇ r1 ⁇ 3 ⁇ m, and/or, 0.01 ⁇ m ⁇ r2 ⁇ 2 ⁇ m.
  • the porosity ⁇ 1 of the first isolation film and the porosity ⁇ 2 of the second isolation film satisfy: 25% ⁇ 1 ⁇ 60%, and/or, 25% ⁇ 2 ⁇ 60% .
  • the tortuosity ⁇ 1 of the first isolation film and the tortuosity ⁇ 2 of the second isolation film satisfy: 1.1 ⁇ 1 ⁇ 3.9, and/or, 1.1 ⁇ 2 ⁇ 3.9.
  • the contact angle ⁇ 1 between the first separator and the first electrolyte, and the contact angle ⁇ 2 between the second separator and the second electrolyte satisfy: 0.35 ⁇ 1 ⁇ 1.35 , and/or, 0.35 ⁇ 2 ⁇ 1.35, unit: radian.
  • the first isolation film in the first cell, includes a first substrate and a first coating provided on at least one surface of the first substrate; the second In the battery cell, the second isolation film includes a second substrate and a second coating provided on at least one surface of the second substrate, and at least one of the following conditions is satisfied:
  • the thickness of the first substrate is 3 ⁇ m to 19.5 ⁇ m; and/or the thickness of the second substrate is 4 ⁇ m to 15 ⁇ m;
  • the thickness of the first coating layer on one side is 0.05 ⁇ m ⁇ 2 ⁇ m; and/or the thickness of the second coating layer on one side is 0.25 ⁇ m ⁇ 3.5 ⁇ m;
  • the first coating layer contains inorganic particles, and the inorganic particles are selected from boehmite ( ⁇ -AlOOH), alumina (Al 2 O 3 ), barium sulfate (BaSO 4 ), magnesium oxide (MgO) , magnesium hydroxide (Mg(OH) 2 ), silicon dioxide (SiO 2 ), tin dioxide (SnO 2 ), titanium oxide (TiO 2 ), calcium oxide (CaO), zinc oxide (ZnO), zirconia ( ZrO 2 ), yttrium oxide (Y 2 O 3 ), nickel oxide (NiO), cerium oxide (CeO 2 ), zirconium titanate (SrTiO 3 ), barium titanate (BaTiO 3 ), magnesium fluoride (MgF 2 ) one or more; optionally, based on the weight of the first coating, the weight percentage of the inorganic particles is 50% to 99%, optionally 70% to 90%;
  • the second coating layer contains at least organic particles, and the organic particles are selected from polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinylidene fluoride, modified polyvinylidene fluoride, Vinylidene fluoride hexafluoropropylene copolymer, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, acrylate, polymethyl methacrylate, polyacrylonitrile, ethyl cellulose, different fluorine-containing alkenyl mono Copolymers of monomer units, copolymers of fluoroalkenyl monomer units and olefinic monomer units, copolymers of fluoroalkenyl monomer units and acrylic monomer units, fluoroalkenyl monomer units and acrylates A copolymer of similar monomer units, and one or more of the above-mentioned modified compounds of each homopolymer or copolymer; optionally,
  • the first coating is provided on both the upper and lower surfaces of the first substrate.
  • the second coating is provided on both the upper and lower surfaces of the second substrate.
  • the positive active material of the first battery cell includes at least one of the lithium-containing phosphate represented by formula (I) or the lithium manganese-based oxide represented by formula (II),
  • M' is selected from one or more of transition metal elements and non-transition metal elements except Fe and Mn;
  • the positive active material of the first cell includes LiFePO 4 , LiMnPO 4 , LiMn 1-x3 Fe x3 PO 4 , LiV 1-x3 Fe x3 PO 4 , LiMn 2 O 4 , LiMn 1.9 One or more of Al 0.1 O 4 , wherein x3 independently satisfies 0 ⁇ x3 ⁇ 1.
  • the lithium-containing phosphate represented by the formula (I) or the lithium-containing phosphate represented by the formula (II) is 100% by weight of the positive active material of the first battery
  • the weight percentage of at least one of the lithium manganese-based oxides is not less than 70%.
  • the positive electrode active material of the second battery cell includes a lithium transition metal oxide represented by formula (III),
  • M is selected from Mn, Fe, Cr, Ti, Zn, V, One or more of Al, Zr and Ce, A is selected from one or more of S, F, Cl and I; optionally, 0.5 ⁇ a ⁇ 0.95, 0 ⁇ b ⁇ 0.15.
  • the weight percentage of the lithium transition metal oxide represented by the formula (III) is not less than 70% based on the weight of the positive electrode active material of the second battery cell as 100%.
  • a second aspect of the present application provides a battery pack, including the battery pack described in the first aspect.
  • a third aspect of the present application provides an electrical device, comprising the battery pack described in the first aspect or the battery pack described in the second aspect, wherein the battery pack or the battery pack serves as a power source of the electrical device. Power supply or energy storage unit.
  • a fourth aspect of the present application provides a method for manufacturing a battery pack, comprising the steps of: acquiring a first type of battery cell and a second type of battery cell, wherein the first type of battery cell and the second type of battery cell are of different chemical chemistry
  • a fifth aspect of the present application provides a manufacturing equipment for a battery pack, including:
  • a clamping arm unit is used to obtain a first type of battery cell and a second type of battery cell
  • the first type of battery cell and the second type of battery cell are batteries of different chemical systems
  • the first type of battery cells One type of cell includes N first cells
  • the second type of cell includes M second cells
  • N and M are positive integers
  • the first cell includes a first isolation membrane and a first electrolyte
  • the second battery core includes a second isolation membrane and a second electrolyte
  • ⁇ 1 and ⁇ 2 are the porosity of the first isolation film and the second isolation film, respectively, unit: %;
  • r1 and r2 are the average pore diameters of the first isolation membrane and the second isolation membrane, respectively, unit: ⁇ m;
  • ⁇ 1 and ⁇ 2 are the tortuosity of the first isolation film and the second isolation film, respectively;
  • t1 and t2 are the average thicknesses of the first isolation film and the second isolation film, respectively, unit: ⁇ m;
  • ⁇ 1 is the contact angle between the first separator and the first electrolyte, unit: radian;
  • ⁇ 2 is the contact angle between the second separator and the second electrolyte, unit: radian;
  • an assembling unit the assembling unit is used to connect the first type battery cells and the second type battery cells at least in series to form the battery pack according to the first aspect;
  • control unit which is used for controlling the clamping arm unit and the assembling unit.
  • the battery pack contains cells with different chemical systems.
  • the kinetic factors of the first cell and the second cell such as a number of key technical indicators of the separator, including the substrate, coating , Comprehensive optimization from bulk to surface, from pore structure to interface contact, etc., to ensure that the dynamic characteristics of the first cell and the second cell match, thereby improving the rate performance and power performance of the battery pack.
  • the battery pack and the electrical device in the present application include the battery pack, they have at least the same technical advantages as the battery pack.
  • FIG. 1 is a schematic diagram showing one example of a cell of the present application.
  • FIG. 2 is an exploded view showing one example of the cell of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram showing one example of the battery pack of the present application.
  • FIG. 4 is a schematic diagram showing one example of the battery pack of the present application.
  • FIG. 5 is an exploded view showing one example of the battery pack of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram showing an example of a power consumption device using the battery pack of the present application as a power source.
  • a “range” disclosed herein is defined in the form of a lower limit and an upper limit, a given range being defined by the selection of a lower limit and an upper limit, the selected lower limit and the upper limit defining the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive, and may be arbitrarily combined, ie, any lower limit may be combined with any upper limit to form a range. For example, if the ranges of 60-120 and 80-110 are listed for a particular parameter, it is to be understood that the ranges of 60-110 and 80-120 are also contemplated.
  • the numerical range "a-b" represents an abbreviated representation of any combination of real numbers between a and b, where both a and b are real numbers.
  • the numerical range "0-5" means that all real numbers between "0-5" have been listed in the text, and "0-5" is just an abbreviated representation of the combination of these numerical values.
  • a parameter is expressed as an integer greater than or equal to 2, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and the like.
  • the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed in sequence, and may also include steps (b) and (a) performed in sequence.
  • reference to the method may further include step (c), indicating that step (c) may be added to the method in any order, eg, the method may include steps (a), (b) and (c) , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • the "comprising” and “comprising” mentioned in this document indicate an open type, and can also be a closed type.
  • the terms “comprising” and “comprising” can mean that other components not listed may also be included or included, or only the listed components may be included or included.
  • the term "or” is inclusive.
  • the phrase “A or B” means “A, B, or both A and B.” More specifically, the condition “A or B” is satisfied by either of the following: A is true (or present) and B is false (or absent); A is false (or absent) and B is true (or present) ; or both A and B are true (or present).
  • cell refers to a battery cell that can be independently charged and discharged.
  • the battery cell includes a positive pole piece, a negative pole piece, a separator, an electrolyte, and an outer package for encapsulating the positive pole piece, the negative pole piece, the separator and the electrolyte, and the like.
  • the application does not have any special restrictions on the type and shape of the cells, which may be soft-wrapped cells, cylindrical cells, or square cells and other types of cells.
  • the batteries in this application can be lithium-ion batteries, potassium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, etc., and are particularly preferably lithium-ion batteries.
  • active ions are intercalated 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.
  • cell refers to a battery cell that can be independently charged and discharged.
  • the components of the battery cell may include positive electrode sheets, negative electrode sheets, separators, electrolytes, and outer packaging for encapsulating the positive electrode sheets, negative electrode sheets, separators, and electrolytes.
  • the application does not have any special restrictions on the type and shape of the cells, which may be soft-wrapped cells, cylindrical cells, or square cells and other types of cells.
  • the batteries in this application can be lithium-ion batteries, potassium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, etc., and are particularly preferably lithium-ion batteries.
  • 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 "chemical system" of the battery cell is divided according to the composition of the positive electrode active material used in the positive electrode sheet in the battery cell, and the elements or substances that are doped or coated with the positive electrode active material are not limited.
  • a battery cell whose positive active material is lithium iron phosphate (including doped with Mn or V element) can be defined as a lithium iron phosphate chemical system battery cell.
  • a cell whose positive active material is nickel cobalt lithium manganate (generally referred to as NCM) can be defined as an NCM chemical system cell.
  • the chemical system of the battery cell can be further limited according to the relative content of nickel , cobalt , and manganese elements in the positive electrode active material.
  • the positive active material is LiNi 0.6 Co 0.2 Mn 0.2 O 2 (generally referred to as NCM622) battery can be defined as NCM622 chemical system battery, the positive active material is LiNi 0.8 Co 0.1 Mn 0.1 O 2 ( Generally referred to as NCM811) cells can be defined as NCM811 chemical system cells.
  • the nickel-cobalt-aluminate lithium system battery (commonly referred to as NCA) as the positive electrode material can be defined as the NCA chemical system battery.
  • NCA nickel-cobalt-aluminate lithium system battery
  • a hybrid system battery cell can also be used, for example, a hybrid system battery cell including NCM and NCA.
  • the battery cell includes a separator, and the separator separates the positive electrode sheet and the negative electrode sheet of the battery cell, providing selective permeation or Barrier, for example, the separator can insulate electrons, physically isolate the positive and negative active materials of the cell, prevent internal short circuits and form an electric field in a certain direction, and at the same time enable ions in the battery to pass through the separator between the positive and negative electrodes. move.
  • the separator can insulate electrons, physically isolate the positive and negative active materials of the cell, prevent internal short circuits and form an electric field in a certain direction, and at the same time enable ions in the battery to pass through the separator between the positive and negative electrodes. move.
  • the release film can be prepared by: (1) providing a substrate; (2) providing a coating slurry: the coating slurry includes component materials, a binder and a solvent, The component materials include inorganic particles and/or organic particles; (3) coating the coating slurry described in step (2) on at least one side of the substrate described in step (1) to form a coating and Dry to obtain the separator.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector and including a positive electrode active material.
  • the positive electrode current collector has two opposite surfaces in its thickness direction, and the positive electrode film layer 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, for example, the metal foil may be an aluminum foil, and the composite current collector may include a polymer material base layer and a layer formed on the polymer material. A metal layer on at least one surface of the material base layer.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) Glycol ester PET, polybutylene terephthalate PBT, polystyrene PS, polyethylene PE and its copolymers etc.
  • metal materials aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.
  • Glycol ester PET polybutylene terephthalate PBT, polystyrene PS, polyethylene PE and its copolymers etc.
  • the positive electrode active material can be a known positive electrode active material for battery cells in the art.
  • the positive active material may include one or more of the following: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for battery cells can also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • lithium transition metal oxides may include but are not limited to lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811)), lithium nickel cobalt aluminum oxide (such as One or more of LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and its modified compounds.
  • lithium cobalt oxides such as LiCoO 2
  • lithium nickel oxides such as LiNi
  • olivine-structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (eg, LiFePO 4 (LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (eg, LiMnPO 4 ), lithium manganese phosphate and carbon One or more of the composite materials, lithium iron manganese phosphate, lithium iron manganese phosphate and carbon composite materials.
  • lithium iron phosphate eg, LiFePO 4 (LFP)
  • composites of lithium iron phosphate and carbon lithium manganese phosphate (eg, LiMnPO 4 )
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the positive electrode film layer also optionally includes a binder.
  • binders that can be used in the positive film layer may include one or more of the following: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene tri- Element copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene-propylene tri- Element copolymer
  • vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer vinyliden
  • the positive electrode film layer may also optionally contain a conductive agent.
  • the conductive agent used in the positive electrode film layer may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode can be prepared by dispersing the above-mentioned components for preparing the positive electrode, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (such as N- Methylpyrrolidone), a uniform positive electrode slurry is formed; the positive electrode slurry is coated on the positive electrode current collector, and the positive electrode sheet can be obtained after drying, cold pressing and other processes.
  • a solvent such as N- Methylpyrrolidone
  • the battery cell of the present application includes a negative electrode plate, the negative electrode plate includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, and the negative electrode film layer contains a negative electrode active material.
  • the negative electrode active material in the negative electrode film layer may be a negative electrode active material commonly used in the art, for example, natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, One or more of lithium titanate.
  • the silicon-based material may be selected from one or more of elemental silicon, silicon oxide, and silicon-carbon composite.
  • the tin-based material can be selected from one or more of elemental tin, tin oxide compounds, and tin alloys.
  • the negative electrode membrane in addition to the negative electrode active material, may further comprise an optional binder, an optional conductive agent and other optional auxiliary agents.
  • the negative electrode membrane of the present application is usually formed by coating and drying the negative electrode slurry.
  • the negative electrode slurry is usually formed by dispersing the negative electrode active material and optional conductive agent and binder in a solvent and stirring uniformly.
  • the above solvent may be N-methylpyrrolidone (NMP) or deionized water.
  • the conductive agent may include one or more of superconducting carbon, carbon black (eg, acetylene black, ketjen black), carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • carbon black eg, acetylene black, ketjen black
  • carbon dots carbon nanotubes, graphene, and carbon nanofibers.
  • the binder may include styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA) , one or more of sodium alginate (SA) and carboxymethyl chitosan (CMCS).
  • the binder may include one of styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS) or several.
  • Other optional auxiliary agents are, for example, thickeners (such as sodium carboxymethyl cellulose CMC-Na), PTC thermistor materials, and the like.
  • the negative pole piece does not exclude other additional functional layers other than the negative electrode film layer.
  • the negative electrode sheet of the present application may further include a conductive primer layer (eg, a conductive agent and a bonding agent) disposed on the surface of the negative electrode current collector sandwiched between the negative electrode current collector and the first negative electrode film layer. composition).
  • the negative electrode sheet of the present application may further include a protective cover layer covering the surface of the second negative electrode film layer.
  • the negative electrode current collector may be a metal foil or a composite current collector, for example, the metal foil may be copper foil, silver foil, iron foil, or a foil composed of an alloy of the above metals.
  • 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. ) formed on the base layer of polymer materials (such as polypropylene PP, polyethylene terephthalate PET, polybutylene terephthalate PBT, polystyrene PS, polyethylene PE and its copolymers, etc.). formed on the base layer).
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the electrolyte solution includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), bisfluorosulfonylidene Lithium Amide (LiFSI), Lithium Bistrifluoromethanesulfonimide (LiTFSI), Lithium Trifluoromethanesulfonate (LiTFS), Lithium Difluorooxalate Borate (LiDFOB), Lithium Dioxalate Borate (LiBOB), Lithium Difluorophosphate One or more of (LiPO 2 F 2 ), lithium difluorodioxalate phosphat
  • the solvent may be selected from one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate ( DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC) ), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and E
  • the content of the solvent is 60-99 wt %, such as 65-95 wt %, or 70-90 wt %, or 75- 89% by weight, or 80-85% by weight. In some embodiments of the present application, based on the total weight of the electrolyte, the content of the electrolyte is 1-40% by weight, such as 5-35% by weight, or 10-30% by weight, or 11- 25% by weight, or 15-20% by weight.
  • the electrolyte may optionally contain additives.
  • the additives may include one or more of the following: 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, Additives to improve low temperature performance of batteries, etc.
  • the above-mentioned positive electrode sheets, negative electrode sheets and separators can be formed into electrode assemblies/bare cell cores through a winding process or a lamination process.
  • the battery cell further includes an outer package, and the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the cell 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 battery cell may be a soft package, such as a bag-type soft package.
  • the material of the soft bag may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), and the like.
  • FIG. 1 is a schematic diagram showing one example of the battery cell 5 of the present application.
  • FIG. 2 is an exploded view showing one example of the battery cell 5 of the present application shown in FIG. 1 .
  • the outer package may include a casing 51 and a cover plate 53 , the casing 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 receiving 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 can be rolled or laminated to form the electrode assembly 52 , the electrode assembly is packaged in the accommodating cavity, and the electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 included in the battery cell 5 may be one or more.
  • a “battery pack” is formed by electrically connecting a certain number of cells together and putting them into a frame in order to protect the cells from external impact, heat, vibration, etc.
  • the shape of the battery cell of the present application can be cylindrical, square or any other shape.
  • the battery pack contains two or more cells, the specific number of which depends on the application of the battery pack and the parameters of a single battery pack.
  • FIG. 3 is a schematic diagram showing one example of the battery pack of the present application.
  • a plurality of cells 5a, 5b may be arranged in sequence along the length direction of the battery pack 4 (5a may be the first cell, 5b may be the second cell). Of course, it can also be arranged in any other manner. Further, the plurality of battery cells 5a and 5b can be fixed by fasteners.
  • the battery pack 4 may further include a housing having an accommodating space, and the plurality of packs 5a, 5b are accommodated in the accommodating space.
  • a battery pack includes at least first type cells and second type cells electrically connected in series, wherein the first type cells and the second type cells are batteries of different chemical systems.
  • the first type of batteries includes N first batteries
  • the second type of batteries includes M second batteries
  • N and M are positive integers
  • the first batteries include a first isolation film and the first electrolyte
  • the second cell includes a second separator and a second electrolyte
  • x1 and x2 satisfy: 0.01 ⁇ x1/x2 ⁇ 160 , where ⁇ 1 and ⁇ 2 are the porosity of the first isolation membrane and the second isolation membrane, respectively, unit: %; r1 and r2 are the average pore sizes of the first isolation membrane and
  • the inventor of the present application uses the kinetic characteristic factor of the cell to characterize the amount of active ions in the cell during the charging and discharging process.
  • Migration ability by matching the kinetic factors of cells of different chemical systems, to overcome the short-board effect of different types of cells in groups, and to improve the overall rate performance and power performance of the battery pack.
  • the kinetic factor of the cell is obtained after comprehensive consideration of the five key parameters of the thickness, pore size, porosity, tortuosity of the separator and the wettability of the electrolyte in the separator.
  • the inventors of the present application have found through painstaking research that the kinetic properties of cells with different chemical systems are quite different. greatly affected. Therefore, it is necessary to keep the ratio of the dynamic characteristic factors of the separators of the two types of cells within a certain range.
  • the first cell and the second cell further satisfy: 0.1 ⁇ x1/x2 ⁇ 100.
  • x1/x2 can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
  • the DC impedance of the battery pack can be further reduced, which helps to overcome the shortcomings of cell assemblies of different types of chemical systems. It can improve the consistency of dynamic characteristics of various types of cells in the battery pack, and improve the rate performance and power performance of the battery pack.
  • the kinetic factor x1 of the first cell satisfies: 0.3 ⁇ x1 ⁇ 95.
  • x1 can be 0.3, 0.35, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87,
  • the kinetic factor x2 of the second cell satisfies: 0.2 ⁇ x2 ⁇ 55.
  • x2 can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, or the range obtained by combining any two of the above within.
  • the average thickness t1 of the first isolation film and the average thickness t2 of the second isolation film satisfy: 4 ⁇ m ⁇ t1 ⁇ 20 ⁇ m, and/or, 8 ⁇ m ⁇ t2 ⁇ 16 ⁇ m.
  • the average thickness t1 of the first isolation film may be 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m, 12 ⁇ m, 13 ⁇ m, 14 ⁇ m, 15 ⁇ m, 16 ⁇ m, 17 ⁇ m, 18 ⁇ m, 19 ⁇ m, 20 ⁇ m, or Its numerical value is within the range obtained by combining any two of the above numerical values.
  • the average thickness t2 of the second isolation film may be 8 ⁇ m, 8.5 ⁇ m, 9 ⁇ m, 9.5 ⁇ m, 10 ⁇ m, 10.5 ⁇ m, 11 ⁇ m, 11.5 ⁇ m, 12 ⁇ m, 12.5 ⁇ m, 13 ⁇ m, 13.5 ⁇ m, 14 ⁇ m, 14.5 ⁇ m, 15 ⁇ m, 15.5 ⁇ m ⁇ m, 16 ⁇ m, or a numerical value thereof within the range obtained by combining any two of the above numerical values.
  • the volume energy density of the battery pack can be kept high, and the mechanical strength of the separators in the respective cells is high. , it is not easy to be affected by foreign objects, the unevenness of the pole piece surface or the side reaction products of the interface, thereby further improving the safety performance of the battery pack.
  • the thicknesses of the first isolation film and the second isolation film can be measured by methods known in the art.
  • the X-ray surface density measuring instrument with the model of Dacheng DC PRECISION can be used to measure the thickness of the material by using the absorption and backscattering effects of X-ray penetrating substances.
  • the contact probe method to test the thickness of the isolation film.
  • a separator material for lithium-ion batteries As a separator material for lithium-ion batteries, it has a microporous structure, which allows it to absorb electrolyte for free lithium ions to be transported between the positive and negative electrodes. Among them, when the micropores are uniformly distributed on the entire large surface of the separator material, consistent electrode/electrolyte interface properties and uniform current density in the battery can be ensured.
  • the uniformity of the size and distribution of the pore size has a direct impact on the battery performance: when the pore size is in an appropriate range, on the one hand, it can reduce the battery impedance, and on the other hand, it can ensure that the positive and negative electrodes cannot be directly contacted or easily pierced by lithium dendrites. cause a short circuit.
  • the average pore size r1 of the first isolation film and the average pore size r2 of the second isolation film satisfy: 0.01 ⁇ m ⁇ r1 ⁇ 3 ⁇ m, and/or, 0.01 ⁇ m ⁇ r2 ⁇ 2 ⁇ m.
  • the average pore size r1 of the first isolation film may be 0.01 ⁇ m, 0.10 ⁇ m, 0.20 ⁇ m, 0.30 ⁇ m, 0.40 ⁇ m, 0.50 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m, 1.0 ⁇ m, 1.1 ⁇ m , 1.2 ⁇ m, 1.3 ⁇ m, 1.4 ⁇ m, 1.5 ⁇ m, 1.6 ⁇ m, 1.7 ⁇ m, 1.8 ⁇ m, 1.9 ⁇ m, 2.0 ⁇ m, 2.1 ⁇ m, 2.2 ⁇ m, 2.3 ⁇ m, 2.4 ⁇ m, 2.5 ⁇ m, 2.6 ⁇ m, 2.7 ⁇ m, 2.8 ⁇ m, 2.9 ⁇ m, 3.0 ⁇ m, or a value thereof within the range obtained by combining any two of the above-mentioned values.
  • the average pore diameter r2 of the second isolation film may be 0.01 ⁇ m, 0.10 ⁇ m, 0.20 ⁇ m, 0.30 ⁇ m, 0.40 ⁇ m, 0.50 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m, 1.0 ⁇ m, 1.1 ⁇ m, 1.2 ⁇ m , 1.3 ⁇ m, 1.4 ⁇ m, 1.5 ⁇ m, 1.6 ⁇ m, 1.7 ⁇ m, 1.8 ⁇ m, 1.9 ⁇ m, 2.0 ⁇ m, or within the range obtained by combining any two of the above values.
  • the pore size of the isolation membrane can be measured by methods known in the art.
  • TriStar II 3020 model automatic adsorption instrument can be used for determination.
  • specific test methods please refer to the standard: GB/T 19587-2017 "Determination of Specific Surface Area of Solid Materials by Gas Adsorption BET Method” and GB/T 21650.2-2008 Determination of pore size distribution and porosity of solid materials by mercury intrusion porosimetry and gas adsorption method.
  • the porosity ⁇ 1 of the first isolation film and the porosity ⁇ 2 of the second isolation film satisfy: 25% ⁇ 1 ⁇ 60%, and/or, 25% ⁇ 2 ⁇ 60 %.
  • the porosity ⁇ 1 of the first isolation film and the porosity ⁇ 2 of the second isolation film may be independently 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5 %, 29%, 29.5%, 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33%, 33.5%, 34%, 34.5%, 35%, 35.5%, 36%, 36.5%, 37%, 37.5%, 38%, 38.5%, 39%, 39.5%, 40%, 40.5%, 41%, 41.5%, 42%, 42.5%, 43%, 43.5%, 44%, 44.5%, 45% , 45.5%, 46%, 46.5%, 47%, 47.5%, 48%, 48.5%, 49%, 49.5%, 50%, 50.5%, 51%, 51.5%, 52%, 52.5%, 53%, 53.5 %, 54%, 54.5%, 55%, 55.5%, 56%, 56.6%, 5
  • the tortuosity ⁇ 1 of the first isolation film and the tortuosity ⁇ 2 of the second isolation film satisfy: 1.1 ⁇ 1 ⁇ 3.9, and/or, 1.1 ⁇ 2 ⁇ 3.9.
  • the tortuosity ⁇ 1 of the first isolation film and the tortuosity ⁇ 2 of the second isolation film may be independently 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, and 2.1.
  • the tortuosity of the separator is an important parameter to describe the tortuosity of the pore channels inside the separator.
  • the tortuosity is defined as the ratio of the actual length of the pore channel to the apparent length (macroscopic distance) passing through the seepage medium, that is, the true length of the particle's movement trajectory in the pore channel when the seepage fluid particle passes through the unit distance of the medium.
  • the tortuosity of the isolation film can be measured using testing methods known in the art.
  • the tortuosity can be calculated by the following formula: Among them, N m represents the McMullin number, and ⁇ is the porosity of the separator. Wherein, the McMullin number N m is the ratio of the resistivity of the separator when immersed in the electrolyte to the resistivity of the electrolyte.
  • the resistivity of the separator immersed in the electrolyte and the resistivity of the electrolyte can be measured by the following methods.
  • electrochemical workstation such as Shanghai Chenhua CHI600E, Solartron or Princeton
  • Rs ⁇ l 0 /(S ⁇ n)
  • a conductivity meter such as Thunder Magnetic DDSJ-318
  • the inventors of the present application have found through intensive research that the pore size, porosity and tortuosity of the separator will affect the dynamic performance, self-discharge rate and lifespan of the cell.
  • the accumulation of reaction products blocks the pore size, which will increase the impedance of the cell, thereby reducing the service life.
  • the pore size, porosity and tortuosity of the separators of the first type of cells and the second type of cells are designed as above, so that the charge-discharge rate, low-temperature performance and low-temperature performance of the cells and the battery pack can be improved. While improving power performance, it reduces the self-discharge rate of cells and battery packs, and improves safety performance and service life.
  • the contact angle ⁇ 1 of the first separator and the first electrolyte, and the contact angle ⁇ 2 of the second separator and the second electrolyte satisfy: 0.35 ⁇ 1 ⁇ 1.35, and/or, 0.35 ⁇ 2 ⁇ 1.35, unit: radian.
  • the contact angle between the separator and the electrolyte reflects the wettability of the electrolyte in the separator and the diffusion rate of the electrolyte in the separator; the smaller the contact angle, the lower the contact angle of the electrolyte The faster the rate of transfer from the surface of the separator to the interior of the separator, the better the kinetic performance of the cell, the better the charge-discharge rate, power performance and low temperature performance; the larger the contact angle, the better the electrolyte from contacting the separator surface to transferring The slower the rate to the inside of the separator, the worse the dynamic performance of the cell, the worse the charge-discharge rate, power performance and low temperature performance.
  • the contact angle between the separator and the electrolyte reflects the wettability of the electrolyte in the separator and the diffusion rate of the electrolyte in the separator.
  • the contact angle between the separator and the electrolyte can be measured using testing methods known in the art.
  • contact angle testing can be performed using methods known in the art.
  • An exemplary test method is as follows: place the test sample on a water contact angle tester (Model SL200KB from Kono Industries, USA), drop 10 ⁇ L of the electrolyte at a height of 1 cm from the positive electrode film layer, and measure the drop through an optical microscope and a high-speed camera. The water droplets on the sample surface are photographed.
  • the test conditions are 25°C, normal pressure (0.1MPa).
  • the angle between the tangent of the water droplet and the surface of the sample contact point and the horizontal plane is measured by software analysis, which is the contact angle, and the unit is radian.
  • the first isolation film in the first cell, includes a first substrate and a first coating provided on at least one surface of the first substrate; the first In the second battery cell, the second isolation film includes a second substrate and a second coating provided on at least one surface of the second substrate.
  • the first substrate and the second substrate are porous structures.
  • the first substrate and the second substrate may each independently be a polymer film formed from one or more polymers selected from the group consisting of: polyolefins (such as polyethylene and polypropylene), polyesters (such as polypara ethylene phthalate and polybutylene terephthalate), polyacetal, polyamide, polyimide, polycarbonate, polyetheretherketone, polyaryletherketone, polyetherimide , polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and teflon , or their two or more copolymers or mixtures, but not limited thereto.
  • polyolefins such as polyethylene and polypropylene
  • polyesters such as polypara ethylene phthalate and polybutylene terephthalate
  • polyacetal polyamide, polyimide, polycarbonate, poly
  • the first substrate and the second substrate may be polyolefin-based substrates of polyolefin. Due to the improved shutdown function of the polyolefin-based substrate, it contributes to improved battery safety. Further optionally, the polyolefin-based substrate can be selected from polyethylene single-layer film, polypropylene single-layer film, polyethylene/polypropylene double-layer film, polypropylene/polyethylene/polypropylene triple-layer film and polyethylene/polypropylene / At least one of the polyethylene three-layer films.
  • the first substrate and the second substrate may include, in addition to the olefin resin, a non-olefin resin, or may include a copolymer of an olefin and a non-olefin monomer.
  • the thickness of the first substrate is 3 ⁇ m ⁇ 15 ⁇ m; and/or the thickness of the second substrate is 4 ⁇ m ⁇ 13 ⁇ m.
  • the thicknesses of the first base material and the second base material are within the above range, on the one hand, the short circuit of the positive and negative pole pieces can be effectively avoided, and at the same time, the volume energy density of the first cell and the second cell can be guaranteed. higher, thereby improving the safety performance and volumetric energy density of the battery pack.
  • the first coating layer contains inorganic particles, and the inorganic particles are selected from boehmite ( ⁇ -AlOOH), alumina (Al 2 O 3 ), barium sulfate (BaSO 4 ) , magnesium oxide (MgO), magnesium hydroxide (Mg(OH) 2 ), silicon dioxide (SiO 2 ), tin dioxide (SnO 2 ), titanium oxide (TiO 2 ), calcium oxide (CaO), zinc oxide ( ZnO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), nickel oxide (NiO), cerium oxide (CeO 2 ), zirconium titanate (SrTiO 3 ), barium titanate (BaTiO 3 ), fluoride One or more of magnesium (MgF2 ) .
  • boehmite ⁇ -AlOOH
  • alumina Al 2 O 3
  • barium sulfate BaSO 4
  • magnesium oxide magnesium oxide
  • the thermal stability of the isolation film of the first cell can be improved, and the thermal shrinkage of the isolation film can be reduced at a higher temperature It can effectively improve the internal short circuit caused by the shrinkage of the isolation film, and greatly improve the safety of the first battery cell.
  • the coated separator since the coated separator has good electrolyte wettability and good oxidation resistance, the kinetics and service life of the cell can be improved.
  • the resistivity of the coating layer is relatively high, and the self-discharge of the first cell can also be improved.
  • the weight percentage of the inorganic particles is 50% to 99%, optionally 70% to 90%.
  • the content of the inorganic particles in the first coating on the surface of the isolation film of the first cell is within the above range, the thermal stability and high resistivity of the isolation film of the first cell can be guaranteed.
  • the uniformity and compactness of the coating meet the characteristics of better pore size, porosity and tortuosity.
  • the second coating layer contains organic particles selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinylidene fluoride, modified polyvinylidene Vinylidene fluoride, vinylidene fluoride hexafluoropropylene copolymer, polyethylene, polypropylene, polyacrylonitrile, polyethylene oxide, acrylate, polymethyl methacrylate, polyacrylonitrile, ethyl cellulose, different containing Copolymers of fluoroalkenyl monomer units, copolymers of fluoroalkenyl monomer units and olefinic monomer units, copolymers of fluoroalkenyl monomer units and acrylic monomer units, fluoroalkenyl monomers A copolymer of units and acrylate monomer units, and one or more of the modified compounds of each of the above-mentioned homopolymers or cop
  • the surface of the isolation film of the second cell is a coating containing organic particles, which can increase the adhesion between the pole pieces. Strong adhesion can improve the hardness of the bare cell, prevent dislocation or deformation, and at the same time It is also beneficial to improve the flatness and consistency of the interface of the second battery cell during the manufacturing and use process, and prevent the occurrence of wrinkling of the pole piece or the occurrence of lithium precipitation and other phenomena.
  • the second coating may further contain inorganic particles, the inorganic particles are selected from boehmite ( ⁇ -AlOOH), alumina (Al 2 O 3 ), barium sulfate ( BaSO 4 ), magnesium oxide (MgO), magnesium hydroxide (Mg(OH) 2 ), silicon dioxide (SiO 2 ), tin dioxide (SnO 2 ), titanium oxide (TiO 2 ), calcium oxide (CaO), Zinc oxide (ZnO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), nickel oxide (NiO), cerium oxide (CeO 2 ), zirconium titanate (SrTiO 3 ), barium titanate (BaTiO 3 ) , one or more of magnesium fluoride (MgF 2 ).
  • boehmite ⁇ -AlOOH
  • alumina Al 2 O 3
  • barium sulfate BaSO 4
  • magnesium oxide MgO
  • the weight percentage of the organic particles is 30% to 99%, optionally 50% to 90%.
  • an effective bonding effect can be ensured without adding excessive weight and/or volume, does not affect the energy density of the cell.
  • the thickness of the first coating layer on one side is 0.05 ⁇ m ⁇ 2 ⁇ m; and/or the thickness of the second coating layer on one side is 0.25 ⁇ m ⁇ 3.5 ⁇ m.
  • the coating thickness on one side of the surface of the isolation film in the first cell and the second cell is within the above range, the volume energy density of the first cell with high chemical stability can be improved, and the volume energy can be improved at the same time.
  • the safety performance of the second cell with higher density improves the overall volumetric energy density and safety of the module.
  • a first coating is provided on both upper and lower surfaces of the first substrate.
  • a second coating is provided on both the upper and lower surfaces of the second substrate.
  • the positive active material of the first battery cell includes at least one of the lithium-containing phosphate represented by formula (I) or the lithium manganese-based oxide represented by formula (II),
  • M' is selected from one or more of transition metal elements and non-transition metal elements except Fe and Mn;
  • the positive active material of the first cell includes LiFePO 4 , LiMnPO 4 , LiMn 1-x3 Fe x3 PO 4 , LiV 1-x3 Fe x3 PO 4 , LiMn 2 O 4 , LiMn 1.9 Al One or more of 0.1 O 4 , wherein x3 independently satisfies 0 ⁇ x3 ⁇ 1.
  • the lithium-containing phosphate has better cycle stability and longer cycle life, and the first battery cell using this type of positive active material has a longer cycle life, which is beneficial to prolong the cycle life of the battery pack.
  • the power output characteristics of the battery pack can be further improved by taking advantage of the technical advantages of the slow power decay of such first cells.
  • the spinel-structured lithium manganate material has better crystal structure stability, and the first cell using this type of positive active material has good rate performance, which is conducive to further improving the rate performance of the battery pack.
  • the positive electrode active material of the second cell includes a lithium transition metal oxide represented by formula (III),
  • M is selected from Mn, Fe, Cr, Ti, Zn, V, One or more of Al, Zr and Ce, and A is selected from one or more of S, F, Cl and I.
  • the above-mentioned positive electrode active material when used in the second battery cell, the above-mentioned material has high gram capacity and high capacity, which can further improve the volume energy density of the second battery cell, so that the volume energy density of the battery pack is also significantly improved.
  • two or more of the above-described battery packs may be assembled into a battery pack, and the number of battery packs contained in the battery pack depends on the application of the battery pack and the parameters of the individual battery packs.
  • the battery pack may include a battery box and a plurality of battery packs arranged in the battery box, the battery box includes an upper box body and a lower box body, the upper box body can be covered on the lower box body and is well matched with it, and is formed for accommodating batteries Group of enclosed spaces.
  • Two or more battery packs can be arranged in the battery box in a desired manner.
  • a "battery pack" is made by further assembling various control and protection systems such as a battery management system and a thermal management system for one or more battery packs (or a combination directly formed by a plurality of cells).
  • FIG. 4 is a schematic diagram showing one example of the battery pack 1 of the present application.
  • FIG. 5 is an exploded view showing one example of the battery pack 1 of the present application shown in FIG. 4 .
  • the battery pack 1 may include a battery case and a plurality of battery packs 4 provided in the battery case.
  • the battery box includes an upper box body 2 and a lower box body 3 .
  • the upper box body 2 is used to cover the lower box body 3 and form a closed space for accommodating the battery pack 4 .
  • the plurality of battery packs 4 can be arranged in the battery case in any manner.
  • the electrical device of the present application includes at least one of a battery pack or a battery pack of the present application, and the battery pack or battery pack can be used as a power source of the electrical device, It can also be used as an energy storage unit for the electrical consumer.
  • the electrical devices include but are not limited to mobile digital devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric Golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • FIG. 6 is a schematic diagram showing an example of a power consumption device using the battery pack of the present application as a power source.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or battery pack can be used.
  • the present application proposes a method for manufacturing a battery pack, comprising the following steps:
  • the first type of batteries and the second type of batteries are batteries of different chemical systems
  • the first type of battery cell includes N first battery cells,
  • the second type of battery cell includes M second battery cells, where N and M are positive integers,
  • the first cell includes a first isolation membrane and a first electrolyte
  • the second battery core includes a second isolation membrane and a second electrolyte
  • ⁇ 1 and ⁇ 2 are the porosity of the first isolation film and the second isolation film, respectively, unit: %,
  • r1 and r2 are the average pore diameters of the first isolation membrane and the second isolation membrane, respectively, unit: ⁇ m,
  • ⁇ 1 and ⁇ 2 are the tortuosity of the first isolation film and the second isolation film, respectively
  • t1 and t2 are the average thicknesses of the first isolation film and the second isolation film, respectively, unit: ⁇ m,
  • ⁇ 1 is the contact angle between the first separator and the first electrolyte, unit: radian
  • ⁇ 2 is the contact angle between the second separator and the second electrolyte, in radians
  • the cells of the first type and the cells of the second type are connected at least in series to form the battery pack according to the first aspect of the present application.
  • the present application proposes a manufacturing equipment for a battery pack, including:
  • the clamping arm unit is used to obtain the first type of cells and the second type of cells,
  • the first type of batteries and the second type of batteries are batteries of different chemical systems
  • the first type of battery cell includes N first battery cells,
  • the second type of battery cell includes M second battery cells, where N and M are positive integers,
  • the first cell includes a first isolation membrane and a first electrolyte
  • the second battery core includes a second isolation membrane and a second electrolyte
  • ⁇ 1 and ⁇ 2 are the porosity of the first isolation film and the second isolation film, respectively, unit: %,
  • r1 and r2 are the average pore diameters of the first isolation membrane and the second isolation membrane, respectively, unit: ⁇ m,
  • ⁇ 1 and ⁇ 2 are the tortuosity of the first isolation film and the second isolation film, respectively
  • t1 and t2 are the average thicknesses of the first isolation film and the second isolation film, respectively, unit: ⁇ m,
  • ⁇ 1 is the contact angle between the first separator and the first electrolyte, unit: radian
  • ⁇ 2 is the contact angle between the second separator and the second electrolyte, unit: radian;
  • control unit which is used for controlling the clamping arm unit and the assembling unit.
  • the positive electrode active material, the conductive carbon Super P, and the binder polyvinylidene fluoride (PVDF) are fully stirred and mixed in an appropriate amount of N-methylpyrrolidone (abbreviated as NMP) solvent at a weight ratio of 95:3:2 to make it.
  • NMP N-methylpyrrolidone
  • a uniform and stable slurry with a viscosity of 10,000 mPa s was formed, and the slurry did not gel, delaminate or settle within 24 hours of standing (wherein, the positive active materials of the first cell and the second cell were See Table 1, Table 2).
  • the positive electrode material slurry is uniformly coated on the Al foil of the positive electrode current collector, and after drying, the polar piece is cold-pressed to a design compaction, and divided into strips for use to obtain a positive electrode polar piece.
  • Negative active materials such as graphite and conductive carbon, binder polystyrene butadiene copolymer (SBR), thickener sodium carboxymethyl cellulose (CMC) in an appropriate weight ratio of 95:2:2:1.
  • SBR binder polystyrene butadiene copolymer
  • CMC thickener sodium carboxymethyl cellulose
  • the isolation film of the first cell includes a PE substrate with a thickness of 7 ⁇ m, and a first coating layer with a thickness of 1 ⁇ m on one side and containing 70 wt % AlOOH inorganic particles.
  • the specific preparation method is as follows: disperse the inorganic particles ⁇ -AlOOH, the binder acrylate emulsion, and sodium carboxymethyl cellulose in the same mass of deionized water with a mass ratio of 70wt%: 25%: 5%. Mix and configure into a first coating slurry; evenly coat the first coating slurry on the surfaces of both sides of the substrate, and after drying, the thickness of the first coating is 1 ⁇ m to obtain the isolation of the first cell membrane.
  • the isolation film of the second type of cell includes a PE substrate with a thickness of 4 ⁇ m, and an inorganic-organic composite coating with a thickness of 0.25 ⁇ m on one side (which includes sequentially arranged on the surface of the substrate: the thickness is 0.15 ⁇ m).
  • the thickness is 0.15 ⁇ m.
  • the specific preparation method is:
  • the parameters of the first cell isolation film and the second cell isolation film are shown in Table 1 and Table 2.
  • the above-mentioned positive pole piece, separator and negative pole piece are wound together to form a bare cell, and then placed in the battery case, injected with the above-mentioned electrolyte, followed by forming, sealing and other processes. Finally got a rechargeable power battery.
  • an X-ray surface density measuring instrument of the model Daesung DC PRECISION can be used as a method of measuring the thickness of the separator. That is, the non-contact measurement of the thickness and areal density of the material is realized by utilizing the absorption and backscattering effects of X-ray penetrating substances.
  • TriStar II 3020 automatic adsorption instrument Measured with TriStar II 3020 automatic adsorption instrument.
  • test methods please refer to the standard: GB/T 19587-2017 "Determination of Specific Surface Area of Solid Materials by Gas Adsorption BET Method” and GB/T 21650.2-2008 Determination of pore size distribution and porosity of solid materials by mercury intrusion porosimetry and gas adsorption method.
  • the degree of tortuosity can be calculated by the following formula: Among them, N m represents the McMullin number, and ⁇ is the porosity of the separator. Wherein, the McMullin number N m is the ratio of the resistivity of the separator when immersed in the electrolyte to the resistivity of the electrolyte.
  • the resistivity of the separator immersed in the electrolyte and the resistivity of the electrolyte can be measured by the following methods.
  • electrochemical workstation such as Shanghai Chenhua CHI600E, Solartron or Princeton
  • Rs ⁇ l 0 /(S ⁇ n)
  • a conductivity meter such as Thunder Magnetic DDSJ-318
  • test sample was placed on a water contact angle tester (Model SL200KB from Kono Industries, USA), 10 ⁇ L of electrolyte was dropped at a height of 1 cm from the positive film layer, and the water droplets on the surface of the sample were photographed by an optical microscope and a high-speed camera.
  • the test conditions are 25°C, normal pressure (0.1MPa).
  • the angle between the tangent of the water droplet and the surface of the sample contact point and the horizontal plane is measured by software analysis, which is the contact angle, and the unit is radian.
  • the battery packs of the following Examples 1 to 14 can be obtained by the above-mentioned "Cell Preparation” method.
  • first cells denoted as A
  • second cells denoted as B
  • electrical properties such as formation capacity, charge and discharge capacity, first coulomb efficiency, impedance, self-discharge, and state of charge
  • the first cell and the second cell are arranged in the order of BAAAAAAB, and are electrically connected in series.
  • the discharge energy retention rate of the battery pack is tested in a high and low temperature box using a charger and discharger.
  • the minimum nominal capacity of the single cell of the first cell and the second cell is C0
  • the battery pack is discharged at a rate of 0.33C0 to the discharge termination voltage of the respective single cell, left for 1 hour, and then discharged at a rate of 0.33C0
  • Charge at a rate until any single cell reaches the end-of-charge voltage, leave it for 5 minutes, charge at a rate of 0.05C0 until any single cell reaches the end-of-charge voltage, and leave it for 1 hour.
  • the ratio of the discharge energy of the battery pack at low temperature to the discharge energy at room temperature is the low temperature discharge energy retention rate.
  • the discharge energy retention rate of the battery pack is tested with a charger and discharger.
  • the cell reaches the end-of-charge voltage leave it for 5 minutes, charge at a rate of 0.05C1 until any cell reaches the end-of-charge voltage, and leave it for 1 hour.
  • the ratio of the discharge capacity under 2C1 of the battery pack to the discharge capacity under 0.33C1 is the rate capacity retention rate.
  • the battery packs of Examples 1-10 and Comparative Examples 1-2 were obtained by assembling the first-type cells and the second-type cells with different kinetic characteristics through the above-mentioned battery pack preparation method.
  • the battery packs of each embodiment and the comparative example were subjected to a discharge energy retention rate test and a rate performance test. See Table 3 for the design parameters and performance test results of each battery pack.
  • the thickness, pore diameter, porosity, and tortuosity of the first isolation film of the first type of cell and the second isolation film of the second type of cell is optimized and matched, so that the dynamic characteristics of the first type of cells and the second type of cells can be well consistent, which can improve the battery pack's high discharge energy retention rate at room temperature and low temperature, and a higher rate of discharge Good performance.
  • the layer structure is an inorganic-organic composite coating with a thickness of 1 ⁇ m on one side (including: a sub-coating of ⁇ -AlOOH inorganic particles with a thickness of 0.6 ⁇ m and a sub-composite coating mixed with PVDF organic particles with a thickness of 0.4 ⁇ m, the specific quality
  • the proportion is shown in Table 4), which can effectively improve the wrinkle degree of the negative pole piece in the fully charged state and further improve the rate performance of the battery pack.

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Abstract

本申请涉及一种电池组，包括至少以串联方式电连接的第一类电芯和第二类电芯，所述第一类电芯和所述第二类电芯为不同化学体系的电芯，所述第一类电芯包括N个第一电芯，所述第二类电芯包括M个第二电芯，N和M为正整数，所述第一电芯包括第一隔离膜及第一电解液，所述第二电芯包括第二隔离膜及第二电解液，所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，且x1与x2满足：0.01≤x1/x2≤160。

Description

电池组、电池包、用电装置以及电池组的制造方法及制造设备 技术领域
本申请涉及储能器件技术领域，尤其涉及一种电池组、电池包、用电装置以及电池组的制造方法和电池组的制造设备。
背景技术
二次电池是一种清洁、可再生资源，其可作为驱动能源或存储单元被应用于汽车、储能等领域。随着对能源环保要求提升，二次电池应用日益普及和广泛。而为了适应不同的环境和应用场景需要，业内对二次电池的性能提出新的要求。
为了提高成组后二次电池的安全性，提出了将多个不同化学体系的单体电芯进行串联和/或并联以形成电池组的技术方案。然而，对于化学体系不同的单体电芯，其动力学特性具有显着差异，将不同电化学特性的电芯串联成电池组后，由于短板效应，电池组的倍率性能和功率性能往往受限于动力学特性较差的单体电芯，造成电池组部分电芯很难充分发挥其电性能优势。
因此，如何匹配电池组中不同化学体系的单体电芯，以保证电池组具有较高的倍率性能和功率性能，是二次电池领域一项急需解决的技术问题。
发明内容
对于混合串联电芯的关键技术，现有技术仅仅停留在概念层面，对于不同化学体系电芯的动力学特性如何进行匹配并没有具体的实施方案说明。特别是，现有技术中，对于电芯和电池组的动力学特性、对动力学特性起关键作用的隔离膜的设计、匹配等均没有具体的实施方案说明，因此无法真正确保电芯、电池组、电池包乃至整车层级的性能发挥。
本申请是鉴于现有技术中存在的上述问题而完成的，其目的在于，提供一 种电池组，其包括化学体系不同的第一类电芯和第二类电芯，第一类电芯和第二类电芯至少以串联的方式电连接。通过对第一类电芯及第二类电芯各自的隔离膜的多项参数进行调整：从基材到涂层、从体相到表面、从孔道结构到界面接触等多方面的综合优化，以实现第一电芯及第二电芯的动力学特性的匹配，从而提升电池组的倍率性能和功率性能。
本申请的第一方面提供一种电池组，包括至少以串联方式电连接的第一类电芯和第二类电芯，所述第一类电芯和所述第二类电芯为不同化学体系的电芯，所述第一类电芯包括N个第一电芯，所述第二类电芯包括M个第二电芯，N和M为正整数，所述第一电芯包括第一隔离膜及第一电解液，所述第二电芯包括第二隔离膜及第二电解液，所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，且x1与x2满足：0.01≤x1/x2≤160，其中，ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％；r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm；τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度；t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm；θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度；θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度。
在本申请任意实施方式中，所述第一电芯与所述第二电芯满足：0.1≤x1/x2≤100。可选地，0.3≤x1/x2≤60。进一步可选地，0.5≤x1/x2≤15。
在本申请任意实施方式中，所述第一电芯与所述第二电芯满足：0.3≤x1≤95，和/或，0.2≤x2≤55。可选地，0.5≤x1≤40，和/或，0.5≤x2≤35。进一步可选地，1≤x1≤20，和/或，1≤x2≤20。
在本申请任意实施方式中，所述第一隔离膜的平均厚度t1与所述第二隔离膜的平均厚度t2满足：4μm≤t1≤20μm，和/或，8μm≤t2≤16μm。可选地，7μm≤t1≤10μm，和/或，11μm≤t2≤14μm。
在本申请任意实施方式中，所述第一隔离膜的平均孔径r1与所述第二隔离膜的平均孔径r2满足：0.01μm≤r1≤3μm，和/或，0.01μm≤r2≤2μm。可选地，0.03μm≤r1≤1.2μm，和/或，0.03μm≤r2≤1μm。
在本申请任意实施方式中，所述第一隔离膜的孔隙率ε1、所述第二隔离膜的孔隙率ε2满足：25％≤ε1≤60％，和/或，25％≤ε2≤60％。可选地，30％≤ε1≤50％，和/或，30％≤ε2≤50％。
在本申请任意实施方式中，所述第一隔离膜的迂曲度τ1与所述第二隔离膜的迂曲度τ2满足：1.1≤τ1≤3.9，和/或，1.1≤τ2≤3.9。可选地，1.3≤τ1≤3，和/或，1.3≤τ2≤3。
在本申请任意实施方式中，所述第一隔离膜与所述第一电解液的接触角θ1、所述第二隔离膜与所述第二电解液的接触角θ2满足：0.35≤θ1≤1.35，和/或，0.35≤θ2≤1.35，单位：弧度。
在本申请任意实施方式中，所述第一电芯中，所述第一隔离膜包括第一基材以及设置与所述第一基材的至少一个表面的第一涂层；所述第二电芯中，所述第二隔离膜包括第二基材以及设置与所述第二基材的至少一个表面的第二涂层，且至少满足以下条件之一：
(1)所述第一基材的厚度为3μm～19.5μm；和/或，所述第二基材的厚度为4μm～15μm；
(2)单侧所述第一涂层的厚度为0.05μm～2μm；和/或，单侧所述第二涂层的厚度为0.25μm～3.5μm；
(3)所述第一涂层中含有无机颗粒，所述无机颗粒选自勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)、硫酸钡(BaSO 4)、氧化镁(MgO)、氢氧化镁(Mg(OH) 2)、二氧化硅(SiO 2)、二氧化锡(SnO 2)、氧化钛(TiO 2)、氧化钙(CaO)、氧化锌(ZnO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、氧化镍(NiO)、氧化铈(CeO 2)、钛酸锆(SrTiO 3)、钛酸钡(BaTiO 3)、氟化镁(MgF 2)中的一种或多种；可选地，以所述第一涂层的重量为基准，所述无机颗粒的重量百分比为50％～99％，可选地70％～90％；
(4)所述第二涂层中至少含有有机颗粒，所述有机颗粒选自聚四氟乙烯、聚偏氟乙烯、聚三氟氯乙烯、聚偏二氟乙烯、改性聚偏氟乙烯、偏氟乙烯六氟丙烯共聚物、聚乙烯、聚丙烯、聚丙烯腈、聚环氧乙烷、丙烯酸酯、聚甲基丙烯酸甲酯、聚丙烯腈、乙基纤维素、不同含氟烯基单体单元的共聚物、含氟烯基单体单元与烯烃基单体单元的共聚物、含氟烯基单体 单元与丙烯酸类单体单元的共聚物、含氟烯基单体单元与丙烯酸酯类单体单元的共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或多种；可选地，以所述第二涂层的重量为基准，所述有机颗粒的重量百分比30％～99％，可选地50％～90％。
在本申请任意实施方式中，所述第一电芯中，所述第一基材的上下两侧表面均设置有第一涂层。
在本申请任意实施方式中，所述第二电芯中，所述第二基材的上下两侧表面均设置有第二涂层。
在本申请任意实施方式中，所述第一电芯的正极活性物质包括式(I)所示的含锂磷酸盐、或式(II)所示的锂锰基氧化物中的至少一种，
LiFe 1-x2-y2Mn x2M’ y2PO 4        式(I)
Li 1+x3Mn eN 2-eO 4-dB d        式(II)
其中，式(I)中，0≤x2≤1，0≤y2≤0.1，M’选自除Fe、Mn外的过渡金属元素以及非过渡金属元素中的一种或几种；式(II)中，-0.1≤x3≤0.2，0＜e≤2，0≤d＜1，N为Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，B为S、N、F、Cl、Br及I中的一种或多种。
在本申请任意实施方式中，所述第一电芯的正极活性物质包括LiFePO 4、LiMnPO 4、LiMn 1-x3Fe x3PO 4、LiV 1-x3Fe x3PO 4、LiMn 2O 4、LiMn 1.9Al 0.1O 4中的一种或几种，其中x3独立地满足0＜x3＜1。
在本申请任意实施方式中，以所述第一电芯的正极活性物质的重量计为100％，所述式(I)所示的含锂磷酸盐、或所述式(II)所示的锂锰基氧化物中的至少一种的重量百分比不低于70％。
在本申请任意实施方式中，所述第二电芯的正极活性物质包括式(III)所示的锂过渡金属氧化物，
Li 1+x1Ni aCo bM 1-a-bO 2-y1A y1       式(III)
其中，-0.1≤x1≤0.2，0.3≤a＜0.95，0＜b＜0.2，0＜a+b＜1，0≤y1＜0.2，M选自Mn、Fe、Cr、Ti、Zn、V、Al、Zr和Ce中的一种或几种，A选自S、F、Cl和I中的一种或几种；可选地，0.5≤a＜0.95，0＜b＜0.15。
在本申请任意实施方式中，以所述第二电芯的正极活性物质的重量计为100％，所述式(III)所示的锂过渡金属氧化物的重量百分比不低于70％。
本申请的第二方面提供一种电池包，包括上述第一方面所述的电池组。
本申请的第三方面提供一种用电装置，包括上述第一方面所述的电池组或上述第二方面所述的电池包，所述电池组或所述电池包作为所述用电装置的电源或能量存储单元。
本申请的第四方面提供一种电池组的制造方法，包括如下步骤：获取第一类电芯和第二类电芯，所述第一类电芯和所述第二类电芯为不同化学体系的电芯，所述第一类电芯包括N个第一电芯，所述第二类电芯包括M个第二电芯，N和M为正整数，所述第一电芯包括第一隔离膜及第一电解液，所述第二电芯包括第二隔离膜及第二电解液，所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，且x1与x2满足：0.01≤x1/x2≤160，其中，ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％；r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm；τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度；t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm；θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度；θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度；以及将所述第一类电芯和第二类电芯以包括串联方式电连接，以形成本申请第一方面所述的电池组。
本申请的第五方面提供一种电池组的制造设备，包括：
夹臂单元，所述夹臂单元用于获取第一类电芯和第二类电芯，所述第一类电芯和所述第二类电芯为不同化学体系的电芯，所述第一类电芯包括N个第一电芯，所述第二类电芯包括M个第二电芯，N和M为正整数，
所述第一电芯包括第一隔离膜及第一电解液，
所述第二电芯包括第二隔离膜及第二电解液，
所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，
所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，
且x1与x2满足：0.01≤x1/x2≤160，其中，
ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％；
r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm；
τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度；
t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm；
θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度；
θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度；
组装单元，所述组装单元用于将所述第一类电芯和所述第二类电芯至少以串联连接，以形成上述第一方面所述的电池组；
以及控制单元，所述控制单元用于控制所述夹臂单元和所述组装单元。
[技术效果]
本申请中，电池组中含有不同化学体系的电芯，通过对第一电芯及第二电芯的动力学因子进行匹配，如隔离膜的多项关键技术指标入手，包括基材、涂层、从体相到表面、从孔道结构到界面接触等多方面综合优化，保证第一电芯及第二电芯的动力学特性匹配，从而提升电池组的倍率性能和功率性能。
由于本申请中的电池包和用电装置包括所述电池组，因而至少具有与所述电池组相同的技术优势。
附图说明
图1是示出本申请的电芯的一个示例的示意图。
图2是示出图1所示的本申请的电芯的一个示例的分解图。
图3是示出本申请的电池组的一个示例的示意图。
图4是示出本申请的电池包的一个示例的示意图。
图5是示出图4所示的本申请的电池包的一个示例的分解图。
图6是示出将本申请的电池组用作电源的用电装置的一个示例的示意图。
其中，附图标记说明如下：
5、5a、5b电芯
51壳体
52电极组件
53盖板
4电池组
1电池包
2上箱体
3下箱体
具体实施方式
本文所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
在本申请中，如果没有特别的说明，本文所提到的所有实施方式以及优选实施方式可以相互组合形成新的技术方案。
在本申请中，如果没有特别的说明，本文所提到的所有技术特征以及优选特征可以相互组合形成新的技术方案。
在本申请中，如果没有特别的说明，本文所提到的所有步骤可以顺序进行，也可以随机进行，但是优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
在本申请中，如果没有特别的说明，本文所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或几种”中“几种”的含义是两种及两种以上。
在本文的描述中，除非另有说明，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
[电芯]
本申请中，“电芯”是指能够独立进行充放电的电池单体。电芯包括正极极片、负极极片、隔离膜、电解液以及用于封装正极极片、负极极片、隔离膜和电解液的外包装等。本申请对电芯的类型、形状没有特别的限制，其可以是软包电芯，也可以是柱形电芯、或是方形电芯等各类电芯。本申请中的电芯可以是锂离子电芯、钾离子电芯、钠离子电芯、锂硫电芯等，特别优选是锂离子电芯。在电池单体的充放电过程中，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，“电芯”是指能够独立进行充放电的电池单体。电芯的组成构件可以包括正极极片、负极极片、隔离膜、电解液以及用于封装正极极片、负极极片、隔离膜和电解液的外包装等。本申请对电芯的类型、形状没有特别的限制，其可以是软包电芯，也可以是柱形电芯、或是方形电芯等各类电芯。本申请中的电芯可以是锂离子电芯、钾离子电芯、钠离子电芯、锂硫电芯等，特别优选是锂离子电芯。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，电芯的“化学体系”是按照电芯中正极极片所使用的正极活性材料的组分进行划分，对正极活性材料的掺杂或包覆的元素或物质不作限定。例如，正极活性材料为磷酸铁锂(包括经Mn或V元素掺杂)的电芯均可以定 义为磷酸铁锂化学体系电芯。正极活性材料为镍钴锰酸锂(一般简称NCM)的电芯可以定义为NCM化学体系电芯。进一步地，可以依据正极活性材料中镍、钴、锰元素的相对含量，对电芯化学体系进一步限定，如，正极活性材料为LiNi 0.5Co 0.2Mn 0.3O 2(一般简称NCM523)的电芯可以定义为NCM523化学体系电芯，正极活性材料为LiNi 0.6Co 0.2Mn 0.2O 2(一般简称NCM622)的电芯可以定义为NCM622化学体系电芯，正极活性材料为LiNi 0.8Co 0.1Mn 0.1O 2(一般简称NCM811)的电芯可以定义为NCM811化学体系电芯。镍钴铝酸锂体系电芯(一般称NCA)为正极材料的电芯可以定义为NCA化学体系电芯。此外，本申请中，也可采用混合体系电芯，例如包括NCM和NCA的混合体系电芯。
下面，首先对本申请中的电芯所具备的隔离膜、正极极片、负极极片、电解液的基本结构进行说明。
<隔离膜>
在本申请的一些实施方式中，所述电芯包括隔离膜，隔离膜将电芯的正极极片与负极极片隔开，对体系内不同种类、尺寸和电荷的物质提供选择性透过或阻隔，例如隔离膜可以对电子绝缘，将电芯的正负极活性物质物理隔离，防止内部发生短路并形成一定方向的电场，同时使得电池中的离子能够穿过隔离膜在正负极之间移动。
在本申请的一些实施方式中，可以通过以下方式制备隔离膜：(1)提供基材；(2)提供涂层浆料：所述涂层浆料包括组分材料、粘结剂和溶剂，所述组分材料包括无机颗粒和/或有机颗粒；(3)将步骤(2)所述的涂层浆料涂布在步骤(1)所述的基材的至少一侧，形成涂层并干燥，得到所述隔离膜。
<正极极片>
本申请的电芯中，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且包括正极活性材料的正极膜层。例如，正极集流体具有在自身厚度方向相背的两个表面，正极膜层设置于正极集流体的两个相背表面中的任意一者或两者上。本申请的电芯中，所述正极集流体可以是金属箔片或复合集流体，例如所述金属箔片可以是铝箔，而所述复合集流体可包括高分子材料基层和形成于该高分子材料基层至少一个表面上的金属层。所述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、聚苯乙烯PS、聚乙烯PE及其共聚物等的基材)上而形成。
在本申请的电芯中，所述正极活性材料可采用本领域公知的用于电芯的正极活性材料。例如，该正极活性材料可包括以下的一种或多种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。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芯正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(NCM333)、LiNi 0.5Co 0.2Mn 0.3O 2(NCM523)、LiNi 0.5Co 0.25Mn 0.25O 2(NCM211)、LiNi 0.6Co 0.2Mn 0.2O 2(NCM622)、LiNi 0.8Co 0.1Mn 0.1O 2(NCM811))、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的一种或几种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的一种或几种。
在一些实施方式中，正极膜层还可选地包括粘结剂。可用于正极膜层的粘结剂的非限制性例子可以包括以下的一种或多种：聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂。
在一些实施方式中，正极膜层还可任选地包含导电剂。用于正极膜层的导电剂的例子可以包括超导碳、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或几种。
在本申请的一些实施方式中，可以通过以下方式制备正极：将上述用于制备正极的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)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，即可得到正极极片。
<负极极片>
本申请的电芯中包括负极极片，所述负极极片包括负极集流体以及设置在所述负极集流体至少一个表面上的负极膜层，所述负极膜层包含负极活性材料。
在本申请的一些实施方式中，负极膜层中的负极活性材料，可以是本领域常用的负极活性材料，例如，天然石墨、人造石墨、软炭、硬炭、硅基材料、锡基材料、钛酸锂中的一种或几种。所述硅基材料可选自单质硅、硅氧化物、硅碳复合物中的一种或几种。所述锡基材料可选自单质锡、锡氧化合物、锡合金中的一种或几种。
本申请的电芯中，所述负极膜片中除包含负极活性材料外，还可以进一步包含可选的粘结剂、可选的导电剂和其他可选助剂。本申请的负极膜片，通常是由负极浆料涂布干燥而成的。负极浆料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。上述溶剂可以是N-甲基吡咯烷酮(NMP)或去离子水。
作为示例，导电剂可包括超导碳、炭黑(例如乙炔黑、科琴黑)、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或几种。
作为示例，粘结剂可包括丁苯橡胶(SBR)、水溶性不饱和树脂SR-1B、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)和羧甲基壳聚糖(CMCS)中的一种或几种。作为示例，粘结剂可包括丁苯橡胶(SBR)、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)中的一种或几种。其他可选助剂例如是增稠剂(如羧甲基纤维素钠CMC-Na)、PTC热敏电阻材料等。
另外，本申请的电芯中，负极极片并不排除除了负极膜层之外的其他附加功能层。例如在某些实施方式中，本申请的负极极片还可包括夹在负极集流体和第一负极膜层之间、设置于负极集流体表面的导电底涂层(例如由导电剂和粘结剂组成)。在另外一些实施方式中，本申请的负极极片还可包括覆盖在第二负极膜层表面的覆盖保护层。
本申请的电芯中，所述负极集流体可以是金属箔片或复合集流体，例如金 属箔片可以是铜箔、银箔、铁箔、或者上述金属的合金构成的箔片。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，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层(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及其共聚物等材料制成的基层)上而形成。
<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。所述电解液包括电解质盐和溶剂。在一些实施方式中，电解质盐可选自六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、高氯酸锂(LiClO 4)、六氟砷酸锂(LiAsF 6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO 2F 2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。
在本申请的一些实施方式中，溶剂可选自以下的一种或多种：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)。
在本申请的一些实施方式中，以所述电解液的总重量为基准计，所述溶剂的含量为60-99重量％，例如65-95重量％，或者70-90重量％，或者75-89重量％，或者80-85重量％。在本申请的一些实施方式中，以所述电解液的总重量为基准计，所述电解质的含量为1-40重量％，例如5-35重量％，或者10-30重量％，或者11-25重量％，或者15-20重量％。
在本申请的一些实施方式中，所述电解液中还可任选地包含添加剂。例如添加剂可以包括以下的一种或多种：负极成膜添加剂、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、改善电池低温性能的添加剂等。
在本申请的一些实施方式中，上述正极极片、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/裸电芯。
在本申请的一些实施方式中，电芯还包括外包装，该外包装可用于封装上述电极组件及电解液。在一些实施方式中，电芯的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。在另一些实施方式中，所述电芯的外包装可以是软包，例如袋式软包。软包的材质可以是塑料，如聚丙烯(PP)、聚对苯二甲酸丁二醇酯(PBT)、聚丁二酸丁二醇酯(PBS)等中的一种或几种。
图1是示出本申请的电芯5的一个示例的示意图。图2是示出图1所示的本申请的电芯5的一个示例的分解图。
所述外包装可包括壳体51和盖板53，壳体51可包括底板和连接于底板上的侧板，所述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，该电极组件封装于所述容纳腔中，所述电解液浸润于电极组件52中。电芯5所含电极组件52的数量可以为一个或多个。
[电池组]
本申请中，“电池组”是为了保护电芯免受外部冲击、热、振动等影响，将一定数目的电芯电连接在一起并放入一个框架中而形成的。本申请的电芯的形状可以是圆柱形、方形或其他任意的形状。
本申请中，可以将若干个电芯组装在一起以构成电池组，电池组中包含两个或更多个电芯，具体数量取决于电池组的应用和单个电池组的参数。
图3是示出本申请的电池组的一个示例的示意图。参照图3，在电池组4中，多个电芯5a、5b可以是沿电池组4的长度方向依次排列设置(其中5a可以为第一电芯，5b可以为第二电芯)。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电芯5a、5b进行固定。可选地，电池组4还可以包括具有容纳空间的外壳，多个组5a、5b容纳于该容纳空间。
<关于第一电芯和第二电芯动力学特征因子的设计>
在本申请的一些实施方式中，电池组包括至少以串联方式电连接的第一类电芯和第二类电芯，所述第一类电芯和第二类电芯为不同的化学体系电芯，所述第一类电芯包括N个第一电芯，所述第二类电芯包括M个第二电芯，N和M为正整数，所述第一电芯包括第一隔离膜及第一电解液，所述第二电芯包括第二隔离膜及第二电解液，所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，且x1与x2满足：0.01≤x1/x2≤160，其中，ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％；r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm；τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度；t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm；θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度；θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度。
为了能够更准确将不同化学体系的电芯组配，形成大容量、高动力学特性的电池组，本申请的发明人以电芯的动力学特征因子表征充放电过程中电芯中活性离子的迁移能力，通过将不同化学体系电芯的动力学因子匹配，克服不同类型电芯成组后的短板效应，提升电池组的整体倍率性能及功率性能。本申请中，电芯的动力学因子是根据隔离膜的厚度、孔径、孔隙率、迂曲度以及电解液在隔离膜中的浸润性五个关键参数综合考虑后得到的。本申请的发明人通过潜心研究发现，不同化学体系的电芯的动力学性能差异较大，若未对其动力学性能进行适应性调配，会导致混合电芯串联电池组的倍率性能、功率性能受到较大影响。因此，需要使两类电芯的隔离膜的动力学特征因子之比处于一定的范围内。
在本申请的一些实施方式中，第一电芯与第二电芯还满足：0.1≤x1/x2≤100。可选地，0.3≤x1/x2≤60。进一步可选地，0.5≤x1/x2≤15。具体地，x1/x2可以为0.01、0.05、0.1、0.15、0.2、0.25、0.3、0.35、0.4、0.5、0.6、0.7、0.8、0.9、1、2、3、4、5、6、7、8、9、10、11、12、13、14、15、16、17、18、19、20、21、22、23、24、25、26、27、28、29、30、31、 32、33、34、35、36、37、38、39、40、41、42、43、44、45、46、47、48、49、50、51、52、53、54、55、56、57、58、59、60、61、62、63、64、65、66、67、68、69、70、71、72、73、74、75、76、77、78、79、80、81、82、83、84、85、86、87、88、89、90、91、92、93、94、95、96、97、98、99、100、101、102、103、104、105、106、107、108、109、110、111、112、113、114、115、116、117、118、119、120、121、122、123、124、125、126、127、128、129、130、131、132、133、134、135、136、137、138、139、140、141、142、143、144、145、146、147、148、149、150、151、152、153、154、155、156、157、158、159、160，或者其数值在上述任意两个数值合并所获得的范围之内。本申请中，当第一电芯与第二电芯的动力学因子比值在上述范围内时，可以进一步降低电池组的直流阻抗，有助于克服不同类化学体系的电芯组配的短板效应，提升电池组中多类电芯的动力学特性一致性，提升电池组的倍率性能及功率性能。
在本申请的一些实施方式中，第一电芯的动力学因子x1满足：0.3≤x1≤95。可选地，0.5≤x1≤40。进一步可选地，1≤x1≤20。具体地，x1可以为0.3、0.35、0.4、0.5、0.6、0.7、0.8、0.9、1、2、3、4、5、6、7、8、9、10、11、12、13、14、15、16、17、18、19、20、21、22、23、24、25、26、27、28、29、30、31、32、33、34、35、36、37、38、39、40、41、42、43、44、45、46、47、48、49、50、51、52、53、54、55、56、57、58、59、60、61、62、63、64、65、66、67、68、69、70、71、72、73、74、75、76、77、78、79、80、81、82、83、84、85、86、87、88、89、90、91、92、93、94、95，或者其数值在上述任意两个数值合并所获得的范围之内。
在本申请的一些实施方式中，第二电芯的动力学因子x2满足：0.2≤x2≤55。可选地，0.5≤x2≤35。进一步可选地，1≤x2≤20。具体地，x2可以为0.2、0.25、0.3、0.35、0.4、0.5、0.6、0.7、0.8、0.9、1、2、3、4、5、6、7、8、9、10、11、12、13、14、15、16、17、18、19、20、21、22、23、24、25、26、27、28、29、30、31、32、33、34、35、36、37、38、39、40、41、42、43、44、45、46、47、48、49、50、51、52、53、54、 55，或者其数值在上述任意两个数值合并所获得的范围之内。
在本申请的一些实施方式中，所述第一隔离膜的平均厚度t1与所述第二隔离膜的平均厚度t2满足：4μm≤t1≤20μm，和/或，8μm≤t2≤16μm。可选地，7μm≤t1≤10μm，和/或，11μm≤t2≤14μm。具体地，所述第一隔离膜的平均厚度t1可以为4μm、5μm、6μm、7μm、8μm、9μm、10μm、11μm、12μm、13μm、14μm、15μm、16μm、17μm、18μm、19μm、20μm，或者其数值在上述任意两个数值合并所获得的范围之内。所述第二隔离膜的平均厚度t2可以为8μm、8.5μm、9μm、9.5μm、10μm、10.5μm、11μm、11.5μm、12μm、12.5μm、13μm、13.5μm、14μm、14.5μm、15μm、15.5μm、16μm，或者其数值在上述任意两个数值合并所获得的范围之内。本申请中，当第一电芯及第二电芯的隔离膜厚度在上述范围内时，可以在保证电池组的体积能量密度较高的同时，由于各自电芯中隔离膜的机械强度较高，不易受到异物、极片表面不平整度或者界面副反应产物的影响，从而进一步提升电池组的安全性能。
在本申请中，第一隔离膜以及第二隔离膜的厚度可以采用本领域公知的方法进行测量。作为示例的，可以使用型号为大成DC PRECISION的X射线面密度测量仪测定，利用X射线穿透物质的吸收、反散射效应实现非接触式测量材料的厚度。可选地，可参考国标GB/T 36363-2018，采用接触式探针法测试隔离膜的厚度。
作为锂离子电池的隔离膜材料，其自身具有微孔结构，容许吸纳电解液，以供游离的锂离子在正负极间传输。其中，当微孔在整个隔离膜材料大面的分布均匀时，可以保证电池中一致的电极/电解液界面性质和均一的电流密度。孔径的大小与分布的均一性对电池性能有直接的影响：孔径在适当的范围内，一方面可以降低电池阻抗，另一方面可以保证正负极无法直接接触或易被锂枝晶刺穿而造成短路。
在本申请的一些实施方式中，所述第一隔离膜的平均孔径r1与所述第二隔离膜的平均孔径r2满足：0.01μm≤r1≤3μm，和/或，0.01μm≤r2≤2μm。可选地，0.03μm≤r1≤1.2μm，和/或，0.03μm≤r2≤1μm。具体地，所述第一隔离膜的平均孔径r1可以为0.01μm、0.10μm、0.20μm、0.30μm、0.40μm、 0.50μm、0.6μm、0.7μm、0.8μm、0.9μm、1.0μm、1.1μm、1.2μm、1.3μm、1.4μm、1.5μm、1.6μm、1.7μm、1.8μm、1.9μm、2.0μm、2.1μm、2.2μm、2.3μm、2.4μm、2.5μm、2.6μm、2.7μm、2.8μm、2.9μm、3.0μm，或者其数值在上述任意两个数值合并所获得的范围之内。所述第二隔离膜的平均孔径r2可以为0.01μm、0.10μm、0.20μm、0.30μm、0.40μm、0.50μm、0.6μm、0.7μm、0.8μm、0.9μm、1.0μm、1.1μm、1.2μm、1.3μm、1.4μm、1.5μm、1.6μm、1.7μm、1.8μm、1.9μm、2.0μm，或者其数值在上述任意两个数值合并所获得的范围之内。
在本申请中，隔离膜的孔径可以采用本领域公知的方法进行测量。作为示例的，可以采用TriStar II 3020型号自动吸附仪测定。具体测试方法可参考标准：GB/T 19587-2017《气体吸附BET法测定固态物质比表面积》以及GB/T 21650.2-2008压汞法和气体吸附法测定固体材料孔径分布和孔隙度。
在本申请的一些实施方式中，所述第一隔离膜的孔隙率ε1与所述第二隔离膜的孔隙率ε2满足：25％≤ε1≤60％，和/或，25％≤ε2≤60％。可选地，30％≤ε1≤50％，和/或，30％≤ε2≤50％。具体地，所述第一隔离膜的孔隙率ε1、所述第二隔离膜的孔隙率ε2可以独立地为25％、25.5％、26％、26.5％、27％、27.5％、28％、28.5％、29％、29.5％、30％、30.5％、31％、31.5％、32％、32.5％、33％、33.5％、34％、34.5％、35％、35.5％、36％、36.5％、37％、37.5％、38％、38.5％、39％、39.5％、40％、40.5％、41％、41.5％、42％、42.5％、43％、43.5％、44％、44.5％、45％、45.5％、46％、46.5％、47％、47.5％、48％、48.5％、49％、49.5％、50％、50.5％、51％、51.5％、52％、52.5％、53％、53.5％、54％、54.5％、55％、55.5％、56％、56.6％、57％、57.5％、58％、58.5％、59％、59.5％、60％，或者其数值在上述任意两个数值合并所获得的范围之内。隔离膜的孔隙率对其透过性和电解液的容纳量非常重要。可以定义为：孔的体积与隔离膜所占体积的比值，即单位膜的体积中孔的体积百分率。
在本申请中，隔离膜的孔隙率可以采用本领域公知的方法进行测量。作为示例的，可以采用AccuPyc II 1340型号真密度测试仪测定。具体测试方法为，分别测试隔离膜的总体积V1以及真实体积V2，根据公式：孔隙率＝(V1-V2)/V1 ×100％，即可得出隔离膜的孔隙率。
在本申请的一些实施方式中，所述第一隔离膜的迂曲度τ1与所述第二隔离膜的迂曲度τ2满足：1.1≤τ1≤3.9，和/或，1.1≤τ2≤3.9。可选地，1.3≤τ1≤3，和/或，1.3≤τ2≤3。具体地，所述第一隔离膜的迂曲度τ1、所述第二隔离膜的迂曲度τ2可以各自独立地为1.1、1.2、1.3、1.4、1.5、1.6、1.7、1.8、1.9、2.0、2.1、2.2、2.3、2.4、2.5、2.6、2.7、2.8、2.9、3.0、3.1、3.2、3.3、3.4、3.5、3.6、3.7、3.8、3.9，或者其数值在上述任意两个数值合并所获得的范围之内。隔离膜的迂曲度是描述隔离膜内部孔通道曲折程度的一个重要参数。迂曲度定义为孔通道的实际长度与穿过渗流介质的视长度(宏观距离)的比值，即渗流流体质点穿越介质单位距离时，质点在孔道中运动轨迹的真实长度。
本申请中，隔离膜的迂曲度可以采用本领域公知的测试方法进行测量。作为示例的，迂曲度可以通过以下公式计算：迂曲度
Figure PCTCN2021090067-appb-000001
其中，N m表示麦克马林数，ε为隔离膜的孔隙率。其中，麦克马林数N m为浸润于电解液时的隔离膜电阻率与该电解液电阻率的比值。浸润于电解液的隔离膜电阻率、以及电解液电阻率可以采用如下方法测试得到。
隔离膜电阻率测试：可采用电化学工作站，型号例如上海辰华CHI600E、Solartron或者Princeton，根据电阻定律公式Rs＝ρ×l 0/(S×n)，使用限域性对称电池EIS法测得不同隔膜层数(n)的Rs，以Rs和n作图得到斜率k＝(ρ×l 0)/S，在已知有效面积S和隔膜厚度l 0的条件下求得电阻率ρ＝(k×S)/l 0。
电解液电阻率测试：采用电导率仪(例如雷磁DDSJ-318)，在25℃、交流阻抗1kHz条件下，测试电解液的电阻R，并根据被测电解液的长度1，截面积S，利用公式ρ＝R×S/l计算电解液的电阻率。
本申请的发明人通过潜心研究发现：隔离膜的孔径、孔隙率和迂曲度会影响电芯的动力学性能、自放电率和寿命。孔径越大、孔隙率越高、迂曲度越小，越有利于电解液的传输，导电率越高，电芯的动力学性能越高，从而充放电倍率、低温性能和功率性能较好；但是，如果孔径过大、孔隙率过高、迂曲度过小，则会容易导致电芯的自放电率较大，严重时会直接导致短路。另外，隔离膜的孔径越小、孔隙率越低、迂曲度越大，自放电 率越低，但是电芯的动力学性能会变差，同时小孔径隔离膜在长期使用过程中容易被界面副反应产物的堆积堵塞孔径，会使电芯的阻抗增加，进而降低使用寿命。
因此，本申请中，通过对第一类电芯和第二类电芯的隔离膜的孔径、孔隙率和迂曲度进行如上设计，从而能够提高电芯及电池组的充放电倍率、低温性能和功率性能的同时，减小电芯及电池组的自放电率，提高安全性能及使用寿命。
在本申请的一些实施方式中，所述第一隔离膜与所述第一电解液的接触角θ1、所述第二隔离膜与所述第二电解液的接触角θ2满足：0.35≤θ1≤1.35，和/或，0.35≤θ2≤1.35，单位：弧度。本申请的发明人通过潜心研究发现：隔离膜与电解液的接触角体现了电解液在隔离膜中的浸润性以及电解液在隔离膜内的扩散速率；接触角越小，则电解液从接触隔离膜表面到传输到隔离膜内部的速率越快，电芯的动力学性能越好，充放电倍率、功率性能和低温性能越好；接触角越大，则电解液从接触隔离膜表面到传输到隔离膜内部的速率越慢，电芯的动力学性能越差，充放电倍率、功率性能和低温性能越差。
因此，本申请中，通过对第一类电芯和第二类电芯的隔离膜与电解液的接触角进行如上设计，从而能够提高电芯及电池组的充放电倍率、低温性能和功率性能。
本申请中，隔离膜与电解液的接触角体现了电解液在隔离膜中的浸润性以及电解液在隔离膜内的扩散速率。隔离膜与电解液的接触角可以采用本领域公知的测试方法进行测量。作为示例的，可采用本领域已知的方法进行接触角测试。示例性测试方法如下：将测试样品放置在水接触角测试仪(美国科诺工业SL200KB型号)上，在距离正极膜层高度为1cm的位置滴10μL电解液，通过光学显微镜和高速相机对落在样品表面的水滴拍照。测试条件为25℃，常压(0.1MPa)。经软件分析测量水滴与样品接触点表面的切线与水平面的夹角，即为接触角，单位为弧度。
在本申请的一些实施方式中，所述第一电芯中，所述第一隔离膜包括第一基材以及设置与所述第一基材的至少一个表面的第一涂层；所述第二电 芯中，所述第二隔离膜包括第二基材以及设置与所述第二基材的至少一个表面的第二涂层。其中，所述第一基材以及第二基材为多孔结构。所述第一基材以及第二基材可以各自独立地由选自以下的一种或多种聚合物形成的聚合物膜：聚烯烃(比如聚乙烯和聚丙烯)、聚酯(比如聚对苯二甲酸乙二醇酯和聚对苯二甲酸丁二醇酯)、聚缩醛、聚酰胺、聚酰亚胺、聚碳酸酯、聚醚醚酮、聚芳醚酮、聚醚酰亚胺、聚酰胺酰亚胺、聚苯并咪唑、聚醚砜、聚苯醚、环烯烃共聚物、聚苯硫醚、聚萘二甲酸乙二醇酯、玻璃纤维、特氟龙和聚四氟乙烯，或它们的两种或多种的共聚物或混合物，但不限于此。
在本申请的一些实施方式中，可选地，第一基材、第二基材可以为聚烯烃的聚烯烃类基板。由于聚烯烃类基板具有改善的关闭功能，因此有助于提高电池安全性。进一步可以选地，聚烯烃类基板可选自聚乙烯单层膜、聚丙烯单层膜、聚乙烯/聚丙烯双层膜、聚丙烯/聚乙烯/聚丙烯三层膜和聚乙烯/聚丙烯/聚乙烯三层膜中的至少一种。另外，第一基材、第二基材除了可以包括烯烃树脂以外，还可以包括非烯烃树脂，或者可以包括烯烃与非烯烃单体的共聚物。
在本申请的一些实施方式中，所述第一基材的厚度为3μm～15μm；和/或，所述第二基材的厚度为4μm～13μm。本申请中当第一基材与第二基材的厚度在上述范围内时，一方面可以有效避免正负极极片短路，同时也可以保证第一电芯与第二电芯的体积能量密度较高，从而提升电池组的安全性能以及体积能量密度。
在本申请的一些实施方式中，所述第一涂层中含有无机颗粒，所述无机颗粒选自勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)、硫酸钡(BaSO 4)、氧化镁(MgO)、氢氧化镁(Mg(OH) 2)、二氧化硅(SiO 2)、二氧化锡(SnO 2)、氧化钛(TiO 2)、氧化钙(CaO)、氧化锌(ZnO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、氧化镍(NiO)、氧化铈(CeO 2)、钛酸锆(SrTiO 3)、钛酸钡(BaTiO 3)、氟化镁(MgF 2)中的一种或多种。本申请中，第一电芯的隔离膜表面的第一涂层中含有上述无机颗粒时，可以提高第一电芯隔离膜的热稳定性，在较高的温度下可以降低隔离膜的热收缩率，可以有效改善由于隔离膜收缩导致的内部短路，极大提升第一电芯的使用安全。同时，由于涂敷后的隔离膜具有较好的电解液浸润性、较好的耐氧化性，因此可 以改善电芯的动力学和使用寿命。而且，第一涂层中含有上述无机颗粒时，涂层的电阻率较高，还可以改善第一电芯的自放电。
在本申请的一些实施方式中，以所述第一涂层的重量为基准，所述无机颗粒的重量百分比为50％～99％，可选地70％～90％。本申请中，第一电芯的隔离膜表面的第一涂层中无机颗粒的含量在上述范围内时，可以在保证第一电芯隔离膜的热稳定性以及高电阻率的前提下，保证涂层的均匀性和致密性，满足较优的孔径、孔隙率和迂曲度特征。
在本申请的一些实施方式中，所述第二涂层含有有机颗粒，所述有机颗粒选自聚四氟乙烯、聚偏氟乙烯、聚三氟氯乙烯、聚偏二氟乙烯、改性聚偏氟乙烯、偏氟乙烯六氟丙烯共聚物、聚乙烯、聚丙烯、聚丙烯腈、聚环氧乙烷、丙烯酸酯、聚甲基丙烯酸甲酯、聚丙烯腈、乙基纤维素、不同含氟烯基单体单元的共聚物、含氟烯基单体单元与烯烃基单体单元的共聚物、含氟烯基单体单元与丙烯酸类单体单元的共聚物、含氟烯基单体单元与丙烯酸酯类单体单元的共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或多种。本申请中，第二电芯的隔离膜表面为含有有机颗粒的涂层，可以增加极片之间的粘结，较强的粘结可以提高裸电芯的硬度，防止发生错位或者变形，同时，也有利于改善第二电芯在制造和使用过程中界面的平整性和一致性，防止发生极片打皱或者产生析锂等现象。
本申请的一些实施方式中，所述第二涂层中还可以进一步含有含有无机颗粒，所述无机颗粒选自勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)、硫酸钡(BaSO 4)、氧化镁(MgO)、氢氧化镁(Mg(OH) 2)、二氧化硅(SiO 2)、二氧化锡(SnO 2)、氧化钛(TiO 2)、氧化钙(CaO)、氧化锌(ZnO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、氧化镍(NiO)、氧化铈(CeO 2)、钛酸锆(SrTiO 3)、钛酸钡(BaTiO 3)、氟化镁(MgF 2)中的一种或多种。
在本申请的一些实施方式中，以所述第二涂层的重量为基准，所述有机颗粒的重量百分比30％～99％，可选地50％～90％。本申请中，第二电芯的隔离膜表面的第二涂层中有机颗粒的含量在上述范围内时，可以既能保证有效的粘结效果，又不会额外增加过多的重量和/或体积，不影响电芯的能量密度。
在本申请的一些实施方式中，单侧所述第一涂层的厚度为0.05μm～2μm；和/或，单侧所述第二涂层的厚度为0.25μm～3.5μm。本申请中，第一电芯及第二电芯中隔离膜表面单侧的涂层厚度在上述范围内时，可以提高化学稳定性较高的第一电芯的体积能量密度，同时改善体积能量密度较高的第二电芯的安全性能，从而提升模组的综合体积能量密度和安全。
在本申请的一些实施方式中，所述第一电芯中，所述第一基材的上下两侧表面均设置有第一涂层。
在本申请的一些实施方式中，所述第二电芯中，所述第二基材的上下两侧表面均设置有第二涂层。
在本申请的一些实施方式中，第一电芯的正极活性物质包括式(I)所示的含锂磷酸盐、或式(II)所示的锂锰基氧化物中的至少一种，
LiFe 1-x2-y2Mn x2M’ y2PO 4          式(I)
Li 1+x3Mn eN 2-eO 4-dB d         式(II)
其中，式(I)中，0≤x2≤1，0≤y2≤0.1，M’选自除Fe、Mn外的过渡金属元素以及非过渡金属元素中的一种或几种；式(II)中，-0.1≤x3≤0.2，0＜e≤2，0≤d＜1，N为Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，B为S、N、F、Cl、Br及I中的一种或多种。
在本申请的一些实施方式中，第一电芯的正极活性物质包括LiFePO 4、LiMnPO 4、LiMn 1-x3Fe x3PO 4、LiV 1-x3Fe x3PO 4、LiMn 2O 4、LiMn 1.9Al 0.1O 4中的一种或几种，其中x3独立地满足0＜x3＜1。本申请中，含锂磷酸盐的循环稳定性较好，具有较长的循环寿命，使用此类正极活性物质的第一电芯的循环寿命较长，有利于延长电池组的循环寿命，在电池组循环寿命的中后期，利用此类第一电芯的功率衰减慢的技术优势，可以进一步提升电池组的功率输出特性。而尖晶石结构的锰酸锂材料的晶体结构稳定性较好，使用此类正极活性物质的第一电芯具有良好的倍率性能，有利于进一步提升电池组的倍率性能。
在本申请的一些实施方式中，第二电芯的正极活性物质包括式(III)所示的锂过渡金属氧化物，
Li 1+x1Ni aCo bM 1-a-bO 2-y1A y1         式(III)
其中，-0.1≤x1≤0.2，0.5≤a＜0.95，0＜b＜0.2，0＜a+b＜1，0≤y1＜0.2，M选自Mn、Fe、Cr、Ti、Zn、V、Al、Zr和Ce中的一种或几种，并且A选自S、F、Cl和I中的一种或几种。本申请中，第二电芯使用上述正极活性物质时，利用上述物质具有高克容量较高，可以进一步提高第二电芯的体积能量密度，从而使得电池组体积能量密度也显着提升。
[电池包]
在本申请的一些实施方式中，可以将两个或更多个上述电池组组装成电池包，电池包所含电池组的数量取决于电池包的应用和单个电池组的参数。电池包可以包括电池箱和设置于电池箱中的多个电池组，该电池箱包括上箱体和下箱体，上箱体能够盖在下箱体上并与之良好匹配，形成用于容纳电池组的封闭空间。两个或更多个电池组可以按照所需的方式排布于该电池箱中。本申请中，“电池包”是对于一个或多个电池组(或者由多个电芯直接形成的组合)进一步装配电池管理系统、热管理系统等各种控制和保护系统而制成的。
图4是示出本申请的电池包1的一个示例的示意图。图5是示出图4所示的本申请的电池包1的一个示例的分解图。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组4。电池箱包括上箱体2和下箱体3，上箱体2用于盖设下箱体3，并形成用于容纳电池组4的封闭空间。多个电池组4可以按照任意的方式排布于电池箱中。
[用电装置]
在本申请的一些实施方式中，本申请的用电装置包括本申请的电池组、或电池包中的至少一种，所述电池组、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置包括但不限于移动数字装置(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。
图6是示出将本申请的电池组用作电源的用电装置的一个示例的示意图。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了 满足该用电装置对高功率和高能量密度的需求，可以采用电池包或电池组。
[电池组的制造方法]
本申请提出一种电池组的制造方法，包括如下步骤：
获取第一类电芯和第二类电芯，
所述第一类电芯和所述第二类电芯为不同化学体系的电芯，
所述第一类电芯包括N个第一电芯，
所述第二类电芯包括M个第二电芯，N和M为正整数，
所述第一电芯包括第一隔离膜及第一电解液，
所述第二电芯包括第二隔离膜及第二电解液，
所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，
所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，
且x1与x2满足：0.01≤x1/x2≤160，其中，
ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％，
r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm，
τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度，
t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm，
θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度，
θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度；以及
将所述第一类电芯和所述第二类电芯至少以串联连接，以形成如本申请第一方面所述的电池组。
[电池组的制造设备]
本申请提出一种电池组的制造设备，包括：
夹臂单元，所述夹臂单元用于获取第一类电芯和第二类电芯，
所述第一类电芯和第二类电芯为不同的化学体系电芯，
所述第一类电芯包括N个第一电芯，
所述第二类电芯包括M个第二电芯，N和M为正整数，
所述第一电芯包括第一隔离膜及第一电解液，
所述第二电芯包括第二隔离膜及第二电解液，
所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，
所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，
且x1与x2满足：0.01≤x1/x2≤160，其中，
ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％，
r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm，
τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度，
t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm，
θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度，
θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度；
组装单元，所述组装单元用于将所述第一类电芯和所述第二类电芯至少以串联连接，以形成如本申请第一方面所述的电池组；以及
控制单元，所述控制单元用于控制所述夹臂单元和所述组装单元。
实施例
下面，通过具体实施例详细描述本申请的技术方案及其优点。
《电芯制备》
参考GB/T 31484-2015《电动汽车用动力蓄电池循环寿命要求及试验方法》，各实施例和对比例中的电芯的制备方法如下。
1、正极浆料的制备
将正极活性材料与导电炭Super P、粘结剂聚偏二氟乙烯(PVDF)按95∶3∶2重量比在适量的N-甲基吡咯烷酮(简写为NMP)溶剂中充分搅拌混合，使其形成均匀的、粘度为10000mPa·s的稳定浆料，浆料静置24小时内，不发生凝胶、分层或者沉降等现象(其中，第一电芯及第二电芯的正极活性材料分别参见表1、表2)。
2、正极极片的制备
将正极材料浆料均匀涂覆于正极集流体Al箔上，干燥后把极片冷压到设计压密，分条备用，得到正极极片。
3、电解液的制备
将等量体积的碳酸乙烯酯溶解在碳酸丙烯酯中，然后将六氟磷酸锂盐均匀溶解在该混合溶剂中备用(六氟磷酸锂的浓度为1.1M/L)，得到电解液。
4、负极极片的制备
将负极活性物质例如石墨与导电炭、粘结剂聚苯乙烯丁二烯共聚物(SBR)、增稠剂羧甲基纤维素钠(CMC)按95∶2∶2∶1重量比在适量的水溶剂中充分搅拌混合，使其形成均匀的负极稳定浆料；将此浆料均匀涂覆于负极集流体Cu箔上，干燥后把极片冷压到设计压密，分条备用。
5、隔离膜
在实施例1中，第一电芯的隔离膜包括厚度为7μm的PE基材，以及单侧厚度为1μm、含有70wt％质量占比的AlOOH无机颗粒的第一涂层。具体制备方法为：将无机颗粒γ-AlOOH、粘结剂丙烯酸酯乳液、羧甲基纤维素钠，以质量占比为70wt％：25％：5％分散在等质量的去离子水中，进行均匀混合，配置成第一涂层浆料；将第一涂层浆料均匀涂敷于基材的两侧的表面，经烘干，第一涂层的厚度为1μm，得到第一电芯的隔离膜。
在实施例1中，第二类电芯的隔离膜包括厚度为4μm的PE基材，以及单侧厚度为0.25μm的无机有机复合涂层(其中，包括在基材表面依次设置：厚度为0.15μm、80wt％质量占比的AlOOH无机颗粒子涂层；以及厚度为0.10μm、30wt％质量占比的PVDF有机颗粒子涂层)。具体制备方法为：
1)将无机颗粒γ-AlOOH、粘结剂丙烯酸酯乳液、羧甲基纤维素钠，以质量占比为80wt％：15％：5％分散在等质量的去离子水中，进行均匀混合，配置成γ-AlOOH无机颗粒子涂层浆料；
2)将PVDF有机颗粒、粘结剂苯乙烯聚丁橡胶，以质量占比为30wt％：70wt％分散在两倍质量的去离子水中，进行均匀混合，配置成PVDF有机颗粒子涂层浆料；
3)将γ-AlOOH无机颗粒子涂层浆料均匀涂敷于基材的两侧的表面，烘干；
4)将PVDF有机颗粒子涂层以喷涂方式部分涂敷于AlOOH无机颗粒子涂层表面，烘干，最终得到第二电芯的隔离膜。
其中，第一电芯隔离膜与第二电芯隔离膜的多项参数，参见表1和表2。
其他实施例中的隔离膜的各个参数如以下的表1所示。
6、电芯的制备
采用常规的电芯制作工艺，将上述正极极片、隔离膜和负极极片一起卷绕成裸电芯，然后置入电池壳体中，注入上述电解液，随之进行化成、密封等工序，最终得到可充电动力电芯。
以下，对于隔离膜及电芯的测试方法进行说明。
《隔离膜的厚度的测试方法》
作为隔离膜的厚度的测量方法，可以使用型号为大成DC PRECISION的X射线面密度测量仪。即，利用X射线穿透物质的吸收、反散射效应实现非接触式测量材料的厚度、面密度。
《隔离膜的孔径的测试方法》
采用TriStar II 3020型号自动吸附仪测定。具体测试方法可参考标准：GB/T 19587-2017《气体吸附BET法测定固态物质比表面积》以及GB/T 21650.2-2008压汞法和气体吸附法测定固体材料孔径分布和孔隙度。
《隔离膜的孔隙率的测试方法》
采用AccuPyc II 1340型号真密度测试仪测定。具体测试方法为，分别测试隔离膜的总体积V1以及真实体积V2，根据公式：孔隙率＝(V1-V2)/V1×100％，即可得出隔离膜的孔隙率。
《隔离膜的迂曲度的测试方法》
迂曲度可以通过以下公式计算：迂曲度
Figure PCTCN2021090067-appb-000002
其中，N m表示麦克马林数，ε为隔离膜的孔隙率。其中，麦克马林数N m为浸润于电解液时的隔离膜电阻率与该电解液电阻率的比值。浸润于电解液的隔离膜电阻率、以及电解液电阻率可以采用如下方法测试得到。
隔离膜电阻率测试：可采用电化学工作站，型号例如上海辰华CHI600E、Solartron或者Princeton，根据电阻定律公式Rs＝ρ×l 0/(S×n)，使用限域性对称电池EIS法测得不同隔膜层数(n)的Rs，以Rs和n作图得到斜率k＝(ρ×l 0)/S，在已知有效面积S和隔膜厚度l 0的条件下求得电阻率ρ＝(k×S)/l 0。
电解液电阻率测试：采用电导率仪(例如雷磁DDSJ-318)，在25℃、交流阻抗1kHz条件下，测试电解液的电阻R，并根据被测电解液的长度1，截面积S，利用公式ρ＝R×S/l计算电解液的电阻率。
《隔离膜与电解液的接触角的测试方法》
将测试样品放置在水接触角测试仪(美国科诺工业SL200KB型号)上，在距离正极膜层高度为1cm的位置滴10μL电解液，通过光学显微镜和高速相机对落在样品表面的水滴拍照。测试条件为25℃，常压(0.1MPa)。经软件分析测量水滴与样品接触点表面的切线与水平面的夹角，即为接触角，单位为弧度。
通过上述《电芯制备》方法，可得到以下的实施例1～14的电池组。
此外，通过上述的测试方法，可以得到示出第一类电芯的隔离膜的厚度、孔径、孔隙率、迂曲度、接触角、动力学特征因子、以及自放电率的表1(电池1-1～1-14)、示出第二类电芯的隔离膜的厚度、孔径、孔隙率、迂曲度、接触角、动力学特征因子、以及自放电率的表2(电池2-1～2-14)。
Figure PCTCN2021090067-appb-000003
Figure PCTCN2021090067-appb-000004
《电池组的组配》
获取6个第一电芯(记为A)和3个第二电芯(记为B)，挑选化成容量、充放电容量、首次库伦效率、阻抗、自放电、荷电状态等电性能一致性较好的电芯，将第一电芯与第二电芯以BAAABAAAB次序进行排列，并通过串联的方式电连接。
《电池组低温放电能量保持率的测试方法》
电池组放电能量保持率使用充放电机在高低温箱内进行测试。第一电芯和第二电芯单体电芯的最小标称容量为C0，将电池组以0.33C0的倍率放电至各自单体电芯的放电终止电压，搁置1小时，然后以0.33C0的倍率进行充电至任一单体电芯达到充电终止电压，搁置5分钟，以0.05C0的倍率充电至任一单体达到充电终止电压，搁置1小时。将电池组以0.33C0的倍率放电至任一单体达到放电终止电压，记录电池组实际放电容量为C1。将电池组以0.33C1的倍率放电至各自单体电芯的放电终止电压，搁置1小时，然后以0.33C1的倍率进行充电至任一单体电芯达到充电终止电压，搁置5分钟，以0.05C1的倍率充电至任一单体达到充电终止电压，搁置1小时。将电池组在目标温度例如0℃下搁置24小时后，以0.33C1的倍率放电至任一单体电池的电压达到产品建议的放电终止电压，且该电压值不得低于室温(25℃)放电终止电压的80％。计算放电能量。电池组在低温下放电能量占室温下放电能量的比例即为低温放电能量保持率。
《电池组倍率性能的测试方法》
电池组放电能量保持率使用充放电机进行测试。先按照上述步骤测试电池组的实际放电容量C1，将电池组以0.33C1的倍率放电至各自单体电芯的放电终止电压，搁置1小时，然后以0.33C1的倍率进行充电至任一单体电芯达到充电终止电压，搁置5分钟，以0.05C1的倍率充电至任一单体达到充电终止电压，搁置1小时。将电池组以2C1倍率放电，直至任一单体电芯达到放电终止电压。计量放电容量。电池组2C1下放电容量占0.33C1下放电容量的比例即为倍率容量保持率。
《电池组100％SOC负极极片褶皱程度的测试方法》
按照上述步骤将电池组进行满充，在满充状态下搁置10小时，之后对电池组中的单体电芯进行拆解。取拆解后的负极极片，观察单位长度单位面积内极片贯穿性、非贯穿性褶皱的程度。
通过上述电池组制备方法，将具有不同动力学特性的第一类电芯和第二类电芯进行组配，得到实施例1～10及对比例1～2的电池组。对各实施例及对比例的电池组进行放电能量保持率测试以及倍率性能测试，各电池组的设计参数及性能测试结果，参见表3。
表3
Figure PCTCN2021090067-appb-000005
根据上述的表3可知，本申请的实施例1～10中，通过对第一类电芯的第一隔离膜和第二类电芯的第二隔离膜的厚度、孔径、孔隙率、迂曲度、与电解液的接触角进行优化匹配设计，从而可使得第一类电芯与第二类电芯的动力学特性一致性良好，进而可提高电池组常温与低温放电能量保持率较高、倍率性能良好。
表4
Figure PCTCN2021090067-appb-000006
Figure PCTCN2021090067-appb-000007
根据上述的表4可知，本申请的实施例6、11～14中，在实施例6的基础上，进一步对第一类电芯的第一隔离膜的涂层结构和组分进行优化，涂层结构为单侧厚度为1μm的无机有机复合涂层(其中包括：厚度为0.6μm的γ-AlOOH无机颗粒子涂层、以及厚度为0.4μm的PVDF有机颗粒混合的子复合涂层，具体质量占比参见表4)，由此可以有效改善满充状态下负极极片的褶皱程度、进一步提升电池组的倍率性能。
本说明书中各实施例或实施方式采用递进方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例间相同相似部分相互参见即可。
在本说明书的描述中，参考术语“一些实施方式”、“一些实施方式”、“示意性实施方式”、“示例”、“具体示例”、或“一些示例”等的描述意指结合实施方式或示例描述的具体特征、结构、材料或者特点包含于本申请的至少一些实施方式或示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施方式或示例。而且，描述的具体特征、结构、材料或者特点可以在任何的一个或多个实施方式或示例中以合适的方式结合。
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。

Claims (15)

  1. 一种电池组，所述电池组包括至少以串联方式电连接的第一类电芯和第二类电芯，所述第一类电芯和所述第二类电芯为不同化学体系的电芯，
    所述第一类电芯包括N个第一电芯，
    所述第二类电芯包括M个第二电芯，N和M为正整数，
    所述第一电芯包括第一隔离膜及第一电解液，
    所述第二电芯包括第二隔离膜及第二电解液，
    所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，
    所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，
    且x1与x2满足：0.01≤x1/x2≤160，其中，
    ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％，
    r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm，
    τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度，
    t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm，
    θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度，
    θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度。
  2. 如权利要求1所述的电池组，其中，所述第一电芯与所述第二电芯满足：0.1≤x1/x2≤100；可选地，0.3≤x1/x2≤60；进一步可选地，0.5≤x1/x2≤15。
  3. 如权利要求1或2所述的电池组，其中，所述第一电芯与所述第二电芯满足：0.3≤x1≤95，和/或，0.2≤x2≤55；
    可选地，0.5≤x1≤40，和/或，0.5≤x2≤35；
    进一步可选地，1≤x1≤20，和/或，1≤x2≤20。
  4. 如权利要求1-3任一项所述的电池组，其中，所述第一隔离膜的平均厚度t1与所述第二隔离膜的平均厚度t2满足：4μm≤t1≤20μm，和/或， 8μm≤t2≤16μm；可选地，7μm≤t1≤10μm，和/或，11μm≤t2≤14μm。
  5. 如权利要求1-4任一项所述的电池组，其中，所述第一隔离膜的平均孔径r1与所述第二隔离膜的平均孔径r2满足：0.01μm≤r1≤3μm，和/或，0.01μm≤r2≤2μm；
    可选地，0.03μm≤r1≤1.2μm，和/或，0.03μm≤r2≤1μm。
  6. 如权利要求1-5任一项所述的电池组，其中，所述第一隔离膜的孔隙率ε1、所述第二隔离膜的孔隙率ε2满足：25％≤ε1≤60％，和/或，25％≤ε2≤60％；
    可选地，30％≤ε1≤50％，和/或，30％≤ε2≤50％。
  7. 如权利要求1-6任一项所述的电池组，其中，所述第一隔离膜的迂曲度τ1与所述第二隔离膜的迂曲度τ2满足：1.1≤τ1≤3.9，和/或，1.1≤τ2≤3.9；
    可选地，1.3≤τ1≤3，和/或，1.3≤τ2≤3。
  8. 如权利要求1-7所述的电池组，其中，所述第一隔离膜与所述第一电解液的接触角θ1、所述第二隔离膜与所述第二电解液的接触角θ2满足：0.35≤θ1≤1.35，和/或，0.35≤θ2≤1.35，单位：弧度。
  9. 如权利要求1-8所述的电池组，其中，
    所述第一电芯中，所述第一隔离膜包括第一基材以及设置与所述第一基材的至少一个表面的第一涂层；所述第二电芯中，所述第二隔离膜包括第二基材以及设置与所述第二基材的至少一个表面的第二涂层，且至少满足以下条件之一：
    (1)所述第一基材的厚度为3μm～19.5μm；和/或，所述第二基材的厚度为4μm～15μm；
    (2)单侧所述第一涂层的厚度为0.05μm～2μm；和/或，单侧所述第二 涂层的厚度为0.25μm～3.5μm；
    (3)所述第一涂层中含有无机颗粒，所述无机颗粒选自勃姆石(γ-AlOOH)、氧化铝(Al 2O 3)、硫酸钡(BaSO 4)、氧化镁(MgO)、氢氧化镁(Mg(OH) 2)、二氧化硅(SiO 2)、二氧化锡(SnO 2)、氧化钛(TiO 2)、氧化钙(CaO)、氧化锌(ZnO)、氧化锆(ZrO 2)、氧化钇(Y 2O 3)、氧化镍(NiO)、氧化铈(CeO 2)、钛酸锆(SrTiO 3)、钛酸钡(BaTiO 3)、氟化镁(MgF 2)中的一种或多种；可选地，以所述第一涂层的重量为基准，所述无机颗粒的重量百分比为50％～99％，可选地70％～90％；
    (4)所述第二涂层含有有机颗粒，所述有机颗粒选自聚四氟乙烯、聚偏氟乙烯、聚三氟氯乙烯、聚偏二氟乙烯、改性聚偏氟乙烯、偏氟乙烯六氟丙烯共聚物、聚乙烯、聚丙烯、聚丙烯腈、聚环氧乙烷、丙烯酸酯、聚甲基丙烯酸甲酯、聚丙烯腈、乙基纤维素、不同含氟烯基单体单元的共聚物、含氟烯基单体单元与烯烃基单体单元的共聚物、含氟烯基单体单元与丙烯酸类单体单元的共聚物、含氟烯基单体单元与丙烯酸酯类单体单元的共聚物，以及上述各均聚物或共聚物的改性化合物中的一种或多种；可选地，以所述第二涂层的重量为基准，所述有机颗粒的重量百分比30％～99％，可选地50％～90％。
  10. 根据权利要求1至9任一项所述的电池组，其中，
    所述第一电芯的正极活性物质包括式(I)所示的含锂磷酸盐、或式(II)所示的锂锰基氧化物中的至少一种，
    LiFe 1-x2-y2Mn x2M’ y2PO 4  式(I)
    Li 1+x3Mn eN 2-eO 4-dB d  式(II)
    其中，式(I)中，0≤x2≤1，0≤y2≤0.1，M’选自除Fe、Mn外的过渡金属元素以及非过渡金属元素中的一种或几种；式(II)中，-0.1≤x3≤0.2，0＜e≤2，0≤d＜1，N为Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，B为S、N、F、Cl、Br及I中的一种或多种；
    可选地，所述第一电芯的正极活性物质包括LiFePO 4、LiMnPO 4、LiMn 1-x3Fe x3PO 4、LiV 1-x3Fe x3PO 4、LiMn 2O 4、LiMn 1.9Al 0.1O 4中的一种或几种， 其中x3独立地满足0＜x3＜1；
    可选地，以所述第一电芯的正极活性物质的重量计为100％，所述式(I)所示的含锂磷酸盐、或所述式(II)所示的锂锰基氧化物中的至少一种的重量百分比不低于70％。
  11. 根据权利要求1至10任一项所述的电池组，其中，
    所述第二电芯的正极活性物质包括式(III)所示的锂过渡金属氧化物，
    Li 1+x1Ni aCo bM 1-a-bO 2-y1A y1  式(III)
    其中，-0.1≤x1≤0.2，0.3≤a＜0.95，0＜b＜0.2，0＜a+b＜1，0≤y1＜0.2，M选自Mn、Fe、Cr、Ti、Zn、V、Al、Zr和Ce中的一种或几种，A选自S、F、Cl和I中的一种或几种；可选地，0.5≤a＜0.95，0＜b＜0.15；
    可选地，以所述第二电芯的正极活性物质的重量计为100％，所述式(III)所示的锂过渡金属氧化物的重量百分比不低于70％。
  12. 一种电池包，其中，包括权利要求1至11中任一项所述的电池组。
  13. 一种用电装置，其中，包括权利要求1至11中任一项所述的电池组或权利要求12所述的电池包，所述电池组或所述电池包可以作为所述用电装置的电源或者能量存储单元。
  14. 一种电池组的制造方法，其中，包括如下步骤：
    获取第一类电芯和第二类电芯，所述第一类电芯和所述第二类电芯为不同化学体系的电芯，
    所述第一类电芯包括N个第一电芯，
    所述第二类电芯包括M个第二电芯，N和M为正整数，
    所述第一电芯包括第一隔离膜及第一电解液，
    所述第二电芯包括第二隔离膜及第二电解液，
    所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，
    所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，
    且x1与x2满足：0.01≤x1/x2≤160，其中，
    ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％，
    r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm，
    τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度，
    t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm，
    θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度，
    θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度；以及
    将所述第一类电芯和第二类电芯以包括串联的方式电连接，以形成权利要求1至11中任一项所述的电池组。
  15. 一种电池组的制造设备，其中，包括：
    夹臂单元，所述夹臂单元用于获取第一类电芯和第二类电芯，所述第一类电芯和第二类电芯为不同的化学体系电芯，
    所述第一类电芯包括N个第一电芯，
    所述第二类电芯包括M个第二电芯，N和M为正整数，
    所述第一电芯包括第一隔离膜及第一电解液，
    所述第二电芯包括第二隔离膜及第二电解液，
    所述第一电芯的动力学特征因子x1为：x1＝1000×(ε1×r1)/(τ1×t1×θ1)，
    所述第二电芯的动力学特征因子x2为：x2＝1000×(ε2×r2)/(τ2×t2×θ2)，
    且x1与x2满足：0.01≤x1/x2≤160，其中，
    ε1、ε2分别为所述第一隔离膜、所述第二隔离膜的孔隙率，单位：％，
    r1、r2分别为所述第一隔离膜、所述第二隔离膜的平均孔径，单位：μm，
    τ1、τ2分别为所述第一隔离膜、所述第二隔离膜的迂曲度，
    t1、t2分别为所述第一隔离膜、所述第二隔离膜的平均厚度，单位：μm，
    θ1为所述第一隔离膜与所述第一电解液的接触角，单位：弧度，
    θ2为所述第二隔离膜与所述第二电解液的接触角，单位：弧度；
    组装单元，所述组装单元用于将所述第一类电芯和所述第二类电芯以包括串联的方式电连接，以形成权利要求1至11中任一项所述的电池组；以及控制单元，所述控制单元用于控制所述夹臂单元和所述组装单元。
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