WO2023184233A1 - 一种包含保护层的电化学装置及电子装置 - Google Patents

一种包含保护层的电化学装置及电子装置 Download PDF

Info

Publication number
WO2023184233A1
WO2023184233A1 PCT/CN2022/084049 CN2022084049W WO2023184233A1 WO 2023184233 A1 WO2023184233 A1 WO 2023184233A1 CN 2022084049 W CN2022084049 W CN 2022084049W WO 2023184233 A1 WO2023184233 A1 WO 2023184233A1
Authority
WO
WIPO (PCT)
Prior art keywords
protective layer
positive electrode
area
electrochemical device
region
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2022/084049
Other languages
English (en)
French (fr)
Inventor
韩冬冬
张青文
刘晓欠
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ningde Amperex Technology Ltd
Original Assignee
Ningde Amperex Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to PCT/CN2022/084049 priority Critical patent/WO2023184233A1/zh
Priority to KR1020247029343A priority patent/KR20240138119A/ko
Priority to CN202280010565.0A priority patent/CN116802855A/zh
Priority to EP22934085.6A priority patent/EP4503203A4/en
Priority to JP2024556174A priority patent/JP2025510735A/ja
Publication of WO2023184233A1 publication Critical patent/WO2023184233A1/zh
Priority to US18/901,099 priority patent/US20250023058A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01M4/64—Carriers or collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/668—Composites of electroconductive material and synthetic resins
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of energy storage, and specifically to an electrochemical device and an electronic device including a protective layer.
  • the present application provides an electrochemical device, which includes a positive electrode including a positive electrode current collector, a first protective layer and a first positive electrode active material layer.
  • the positive current collector includes opposing first and second surfaces.
  • the first protective layer is disposed between the first surface and the first cathode active material layer.
  • the first surface includes a first region and a second region, the first region is provided with the first cathode active material layer, and the second region is not provided with the first cathode active material layer.
  • the area of the first region is A1cm 2
  • the area of the second region is A2cm 2
  • the area of the first protective layer is A3cm 2 , satisfying: 0.5 ⁇ A3/(A1+A2) ⁇ 1.
  • the first surface of the positive electrode current collector can be fully protected by the first protective layer, and the first protective layer can isolate the positive electrode current collector during the process of being impacted or punctured by external forces.
  • the conduction between the positive electrode current collector and the negative electrode active material layer suppresses the most dangerous short circuit between the positive electrode current collector and the negative electrode active material layer, and improves the safety performance of the electrochemical device.
  • the cathode is a rolled structure
  • the rolled structure includes a rolling starting end located inside the rolled structure and a rolling end located outside the rolled structure, and the second region Located at the winding end, and 0 ⁇ A2/A1 ⁇ 0.2.
  • the second area is located outside the winding structure.
  • the area of the first protective layer on the first region is B1cm2, which satisfies: 0.8 ⁇ B1/A1 ⁇ 1.
  • the piercing object pierces the first area, if a short circuit occurs between the positive electrode current collector and the negative electrode active material layer, since the positive electrode active material layer is provided on the first area, the electron conduction path is short at this time, and the instantaneous short circuit current will exceed It is large and prone to fire and explosion.
  • 0.8 ⁇ B1/A1 ⁇ 1 the first area of the positive electrode current collector can be fully protected by the first protective layer, suppressing the gap between the positive electrode current collector and the negative electrode active material layer in the first area. short circuit, thereby improving the safety performance of electrochemical devices.
  • the area of the protective layer on the second region is B2cm2, where 0.5 ⁇ B2/A2 ⁇ 1 is satisfied.
  • the second region can be fully protected by the first protective layer, suppressing the occurrence of short circuit between the positive electrode current collector and the negative electrode active material layer in the second region, thereby improving the safety performance of the electrochemical device.
  • the positive electrode further includes a second positive electrode active material layer and a second protective layer located between the second surface and the second positive electrode active material layer; the second surface includes the second positive electrode active material layer and the second positive electrode active material layer. a third area opposite to the first area and a fourth area opposite to the second area; the area of the second protective layer on the third area is C1, and the second protective layer on the fourth area The area of the protective layer is C2, which satisfies: 0.8 ⁇ C1/A1 ⁇ 1, and/or 0.5 ⁇ C2/A2 ⁇ 1.
  • both the second region and/or the fourth region can be fully protected by the second protective layer, which reduces the possibility of burrs forming on the second surface of the positive electrode current collector puncture point to pierce the diaphragm during the puncture process, resulting in the most dangerous occurrence.
  • the risk of short circuit between the positive electrode current collector and the negative electrode active material layer thereby improving the safety performance of the electrochemical device.
  • the resistance value of the positive electrode in the first region is R1
  • the resistance value of the positive electrode in the second region is R2, satisfying: 1.5 ⁇ R1 ⁇ 10.5; and/or 1 ⁇ R2 ⁇ 10.
  • the electrochemical device can have both excellent electrochemical performance and safety performance.
  • the first protective layer includes first inorganic particles, a first binder, and a first conductive agent.
  • the second protective layer includes second inorganic particles, a second binder, and a second conductive agent.
  • the first binder and/or the second binder satisfies at least one of the following characteristics: (1) containing acrylic acid, acrylamide, acrylate, acrylonitrile or acrylate At least one formed polymer; (2) comprising at least one of carboxymethylcellulose salt or nitrile rubber.
  • the first adhesive and/or the second adhesive is a water-based adhesive.
  • the first inorganic particles and/or the second inorganic particles comprise aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide , at least one of calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, diaspore, barium sulfate, calcium sulfate or calcium silicate.
  • the first conductive agent and/or the second conductive agent includes at least one of sheet-like, mesh-like, linear or granular conductive agents.
  • the mass percentage of the first inorganic particles is 60% to 99%. In some embodiments, based on the mass of the first protective layer, the mass percentage of the first binder is 0.5% to 22%. In some embodiments, based on the mass of the first protective layer, the mass percentage of the first conductive agent is 0.1% to 11%.
  • the mass percentage of the second inorganic particles is 60% to 99%.
  • the mass percentage of the second adhesive is 0.5% to 22% based on the mass of the second protective layer.
  • the mass percentage of the second conductive agent is 0.1% to 11%.
  • the first protective layer further includes a first leveling agent; and/or the second protective layer further includes a second leveling agent.
  • the mass percentage of the first leveling agent is greater than 0% and less than or equal to 5%. In some embodiments, based on the mass of the second protective layer, the mass percentage of the second leveling agent is greater than 0% and less than or equal to 5%.
  • the first leveling agent and/or the second leveling agent includes silicone compounds, silicone derivatives, oxygen-containing olefin polymers, carboxylate compounds, carboxylic acids At least one of salt compounds, alcohol compounds, ether compounds or fluorocarbon compounds.
  • the present application relates to an electronic device comprising an electrochemical device according to any of the preceding embodiments.
  • Figure 1 shows a positive electrode for an electrochemical device according to some embodiments of the present application.
  • Figure 2 shows a positive electrode for an electrochemical device according to some embodiments of the present application.
  • Figure 3 shows a positive electrode for an electrochemical device according to some embodiments of the present application.
  • a list of items connected by the term “and/or” may be meant to include any and all combinations of one or more of the associated listed items. For example, if items A and B are listed, the phrase “A and/or B” means only A; only B; or A and B. In the detailed description and claims, a list of items connected by the term “at least one of,” “at least one of,” “at least one of,” or other similar terms may mean that the listed items any combination of. For example, if items A and B are listed, the phrase "at least one of A and B" means only A; only B; or A and B.
  • the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B and C.
  • Project A can contain a single component or multiple components.
  • Project B can contain a single component or multiple components.
  • Project C may contain a single component or multiple components.
  • FIG. 1 shows a positive electrode 10 for an electrochemical device according to some embodiments of the present application.
  • the positive electrode 10 includes a positive current collector 12, a first protective layer 14a, a second protective layer 14b, a first positive active material layer 16a and a second positive active material layer 16b.
  • the positive current collector includes opposing first surfaces 12a and second surfaces 12b.
  • the first protective layer 14a is disposed between the first surface 12a and the first cathode active material layer 16a.
  • the second protective layer 14b is disposed between the second surface 12b and the second cathode active material layer 16b.
  • the first surface 12a includes a first region 18a and a second region 18b.
  • the first region 18a is provided with the first cathode active material layer 16a.
  • the second region 18b is not provided with the first positive electrode active material layer 16a.
  • Positive active material layer 16a is provided.
  • the area of the first region 18a is A1cm2, the area of the second region 18b is A2cm2, and the area of the first protective layer 14a is A3cm2, satisfying: 0.5 ⁇ A3/(A1+A2 ) ⁇ 1.
  • the first surface 12a of the positive electrode current collector 12 can be fully protected by the first protective layer 14a, and the first protective layer 14a can insulate it when being impacted or punctured by external force.
  • the positive electrode current collector 12 is connected to the negative electrode active material layer, thereby suppressing the most dangerous short circuit between the positive electrode current collector and the negative electrode active material layer, and improving the safety performance of the electrochemical device.
  • A3/(A1+A2) is equal to 1.
  • the cathode is a rolled structure
  • the rolled structure includes a rolling starting end located inside the rolled structure and a rolling end located outside the rolled structure
  • the second region 18b is located at the winding end, and 0 ⁇ A2/A1 ⁇ 0.2.
  • the second region 18b is located outside the winding structure.
  • A2/A1 is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2 or a range between any two of the aforementioned values.
  • the area of the first protective layer 14a on the first region 18a is B1cm2, which satisfies: 0.5 ⁇ B1/A1 ⁇ 1. In some embodiments, 0.8 ⁇ B1/A1 ⁇ 1. In some embodiments, B1/A1 is 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1 or a range between any two of the aforementioned values.
  • the instantaneous short-circuit current will be too large, which may easily cause fire or explosion.
  • the first region 18a of the positive electrode current collector can be fully protected by the first protective layer 14a and suppress the positive electrode current collector in the first region 18a.
  • a short circuit occurs between the fluid and the negative active material layer, thereby improving the safety performance of the electrochemical device.
  • the area of the protective layer 14a on the second region 18b is B2cm 2 and satisfies: 0.5 ⁇ B2/A2 ⁇ 1.
  • B2/A2 is 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1 or a range between any two of the aforementioned values.
  • the second region 18b can be fully protected by the first protective layer, suppressing the occurrence of short circuit between the positive electrode current collector and the negative electrode active material layer in the second region 18b, thereby improving the safety performance of the electrochemical device.
  • the second surface 12b includes a third area 19a opposite the first area 18a and a fourth area 19b opposite the second area 18b; all areas on the third area 19a
  • the area of the second protective layer 16b is C1, which satisfies: 0.5 ⁇ C1/A1 ⁇ 1.
  • C1/A1 is 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1 or a range between any two of the aforementioned values.
  • the area of the second protective layer 16b on the fourth region 19b is C2, which satisfies: 0.5 ⁇ C2/A2 ⁇ 1.
  • C2/A2 is 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1 or a range between any two of the aforementioned values.
  • the third region 19a and/or the fourth region 19b can be fully protected by the second protective layer 16b, which reduces the burrs formed on the second surface 12b at the puncture point of the positive electrode current collector from piercing the separator during the puncture process, resulting in The most dangerous risk of short circuit occurs between the positive electrode current collector and the negative electrode active material layer, thereby improving the safety performance of the electrochemical device.
  • Figure 2 shows a positive electrode 20 for an electrochemical device according to some embodiments of the present application.
  • the difference between the positive electrode 20 shown in FIG. 2 and that shown in FIG. 1 includes that the portion of the fourth area 19b opposite to the second area 18b of the second surface 12b of the current collector 12 in the positive electrode 20 of FIG. 2 is not protected by the second protection.
  • Layer 14b covers.
  • Figure 3 shows a positive electrode 30 for an electrochemical device according to some embodiments of the present application.
  • the difference between the positive electrode 30 shown in FIG. 3 and that shown in FIG. 1 includes that the entire second region 18b of the first surface 12a of the current collector 12 in the positive electrode 30 of FIG. 3 is not covered by the first protective layer 34a.
  • the resistance value of the positive electrode in the first region 18a is R1 ⁇ 2, 1.5 ⁇ R1 ⁇ 10.5.
  • R1 is 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5 or any two of the aforementioned values range between.
  • the electrochemical device can have both excellent electrochemical performance and safety performance.
  • the resistance value of the positive electrode in the second region 18b is R2 ⁇ 2, 1 ⁇ R2 ⁇ 10.
  • R1 is 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 or any two of the aforementioned values range between.
  • the electrochemical device can have excellent safety performance.
  • the first protective layer includes first inorganic particles, a first binder, and a first conductive agent.
  • the second protective layer includes second inorganic particles, a second binder, and a second conductive agent.
  • the first inorganic particles and/or the second inorganic particles include aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, At least one of zirconium oxide, yttria, silicon carbide, boehmite (boehmite), aluminum hydroxide, magnesium hydroxide, calcium hydroxide, diaspore, barium sulfate, calcium sulfate or calcium silicate.
  • the mass percentage of the first inorganic particles is 60% to 99%. In some embodiments, the mass percentage of the first inorganic particles is 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99% or a range between any two of the aforementioned values.
  • the mass percentage of the second inorganic particles is 60% to 99% based on the mass of the second protective layer. In some embodiments, the mass percentage of the second inorganic particles is 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99% or a range between any two of the aforementioned values.
  • the first binder includes a polymer formed from at least one of acrylic acid, acrylamide, an acrylate, acrylonitrile, or an acrylate.
  • the first binder includes at least one of carboxymethylcellulose salt or nitrile rubber.
  • the second binder includes a polymer formed from at least one of acrylic acid, acrylamide, an acrylate, acrylonitrile, or an acrylate.
  • the second binder includes at least one of carboxymethylcellulose salt or nitrile rubber.
  • the first adhesive is an aqueous adhesive.
  • the second adhesive is an aqueous adhesive.
  • the first binder and/or the second binder have good hydrophilic and oleophobic properties, so that the first protective layer and/or the second protective layer have excellent adhesion and stability in the oily electrolyte. properties, thereby improving the safety performance of electrochemical devices.
  • the mass percentage of the first binder is 0.5% to 22% based on the mass of the first protective layer. In some embodiments, the mass percentage of the first adhesive is 5% to 15% based on the mass of the first protective layer. In some embodiments, the mass percentage of the first binder is 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11% , 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22% or the range between any two of the aforementioned values. In some embodiments, the mass percentage of the second binder is 0.5% to 22% based on the mass of the second protective layer.
  • the mass percentage of the second binder is 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11% , 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22% or the range between any two of the aforementioned values.
  • the first conductive agent and/or the second conductive agent includes at least one of sheet-like, mesh-like, linear or granular conductive agents.
  • the first conductive agent and/or the second conductive agent includes graphene (GN for short), graphite fiber, carbon nanotube (CNT for short), Ketjen black or conductive carbon (SP for short). ) at least one of the following.
  • the mass percentage of the first conductive agent is 0.1% to 11% based on the mass of the first protective layer. In some embodiments, the mass percentage of the first conductive agent is 0.1%, 0.4%, 0.6%, 0.8%, 1%, 1.6%, 1.8%, 2%, 3%, 4%, 5%, 6%, 7%, 9%, 10%, 11% or the range between any two of the aforementioned values. In some embodiments, the mass percentage of the second conductive agent is 0.1% to 11% based on the mass of the second protective layer.
  • the mass percentage of the second conductive agent is 0.1%, 0.4%, 0.6%, 0.8%, 1%, 1.6%, 1.8%, 2%, 3%, 4%, 5%, 6%, 7%, 9%, 10%, 11% or the range between any two of the aforementioned values.
  • the first protective layer further includes a first leveling agent.
  • the second protective layer further includes a second leveling agent.
  • the first leveling agent and/or the second leveling agent include silicone compounds, silicone derivatives, oxygen-containing olefin polymers, carboxylate compounds, carboxylates At least one of compounds, alcohol compounds, ether compounds or fluorocarbon compounds.
  • the mass percentage of the first leveling agent is greater than 0% and less than or equal to 5%.
  • the mass percentage of the first leveling agent is 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or the range between any two of the aforementioned values.
  • the mass percentage of the second leveling agent is greater than 0% and less than or equal to 5%.
  • the mass percentage of the second leveling agent is 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2% , 0.3%, 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or the range between any two of the aforementioned values.
  • the addition of leveling agent is conducive to the formation of a uniform and smooth protective layer, increases the contact area between the protective layer and the current collector and the positive active material layer, and improves the safety performance of the electrochemical device.
  • the positive active material layer includes an active material, a third binder, and a third conductive agent.
  • the active material includes lithium cobalt oxide (abbreviated as LCO).
  • the mass percentage of the active material is 94% to 99% based on the mass of the cathode active material layer. In some embodiments, based on the mass of the cathode active material layer, the mass percentage of the active material is 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99% or the range between any two values mentioned above.
  • the third binder includes at least one of polyvinylidene fluoride (abbreviated as PVDF), nitrile rubber, or polyacrylate.
  • the mass percentage of the third binder is 0.5% to 2.5% based on the mass of the cathode active material layer. In some embodiments, based on the mass of the cathode active material layer, the mass percentage of the third binder is 0.5%, 1%, 1.5%, 2%, 2.5% or a range between any two of the aforementioned values.
  • the third conductive agent includes at least one of graphene, graphite fiber, carbon nanotube, Ketjen black or conductive carbon.
  • the mass percentage of the third conductive agent is 0.5% to 3.5% based on the mass of the cathode active material layer. In some embodiments, based on the mass of the cathode active material layer, the mass percentage of the third conductive agent is 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or between any two of the aforementioned values. scope.
  • This application can improve the safety of the electrochemical device when it is impacted or punctured by external forces by arranging a protective layer between the positive current collector and the positive active material layer of the electrochemical device, and controlling the coverage of the protective layer on the current collector; at the same time, , it can also simplify the application method of the protective layer and improve processing efficiency.
  • the electrochemical device of the present application also includes a separator, an electrolyte and a negative electrode.
  • electrochemical devices of the present application include primary or secondary batteries.
  • the electrochemical device is a lithium secondary battery.
  • lithium secondary batteries include, but are not limited to: lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.
  • the preparation method of the electrochemical device of the present application is described in detail below by taking a lithium-ion battery as an example.
  • Preparation of the negative electrode Disperse the negative electrode active material (at least one of carbon material, silicon material or lithium titanate) and negative electrode binder, as well as optional conductive material, into the solvent system according to a certain mass ratio and stir thoroughly. After uniformity, it is coated on the negative electrode current collector, dried and cold pressed to obtain the negative electrode.
  • the negative electrode active material at least one of carbon material, silicon material or lithium titanate
  • the negative electrode binder as well as optional conductive material
  • Preparation of the positive electrode (1) Add the inorganic particles, the first conductive agent, the first binder, and the optional leveling agent to the solvent and mix evenly to obtain the slurry of the protective layer (hereinafter referred to as the "first Slurry”); (2) Coat the first slurry in step (1) on the target area of the positive electrode current collector; (3) Apply the positive electrode current collector containing the first slurry obtained in step (2) Dry to remove the solvent to obtain a positive electrode current collector coated with a protective layer; (4) Disperse the active material, the third conductive agent, and the third binder in the solvent system according to a certain mass ratio and stir thoroughly to obtain The slurry of the positive electrode active material (hereinafter referred to as the "second slurry”); (5) applying the second slurry to the target area of the positive electrode current collector coated with the protective layer obtained in step (3); ( 6) Dry the positive electrode current collector containing the second slurry in step (5) to remove the solvent, thereby obtaining the desired positive electrode.
  • first Slurry the
  • first conductive agent first binder
  • active material third conductive agent and third binder
  • examples of the solvent include, but are not limited to, N-methylpyrrolidone, acetone, or water. In some embodiments, the amount of solvent can be adjusted appropriately.
  • the current collector has a thickness in the range of 3 microns to 20 microns, although the disclosure is not limited thereto.
  • the current collector is not particularly limited as long as the current collector is conductive without causing adverse chemical changes in the manufactured battery.
  • Examples of the current collector include copper, stainless steel, aluminum, nickel, titanium, or alloys (eg, homo-nickel alloys), but the disclosure is not limited thereto.
  • fine irregularities eg, surface roughness
  • the current collector can be used in various forms, and examples thereof include films, sheets, foils, meshes, porous structures, foams, or similar materials, but the disclosure is not limited thereto.
  • Isolation film In some embodiments, a polyethylene (abbreviated as PE) porous polymer film is used as the isolation film.
  • the material of the isolation membrane may include fiberglass, polyester, polyethylene, polypropylene, polytetrafluoroethylene or combinations thereof.
  • the pores in the isolation film have a diameter in the range of 0.01 micron to 1 micron, and the thickness of the isolation film ranges from 5 microns to 500 microns.
  • the electrolyte includes an organic solvent, a lithium salt, and additives.
  • the organic solvent includes ethylene carbonate (abbreviated as EC), propylene carbonate (abbreviated as PC), diethyl carbonate (abbreviated as DEC), ethyl methyl carbonate (abbreviated as EMC), dimethyl carbonate At least one of ester (abbreviated as DMC), propylene carbonate or ethyl propionate.
  • the lithium salt includes at least one of an organic lithium salt or an inorganic lithium salt.
  • lithium salts include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bistrifluoromethanesulfonimide LiN (CF 3 8O 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium bis(fluorosulfonyl)borate LiB(C 2 O 4 ) 2 (LiBOB) or lithium difluoroxalatoborate At least one of LiBF 2 (C 2 O 4 ) (LiDFOB).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiPO 2 F 2 lithium difluorophosphate
  • LiN CF 3 8O 2 ) 2
  • LiTFSI lithium bis(fluorosulfonyl)imide Li
  • the bare battery core obtained by winding is placed in an outer package, electrolyte is injected and packaged, and a lithium-ion battery is obtained through processes such as formation, degassing, and trimming.
  • the present application provides an electronic device comprising the electrochemical device according to the foregoing content.
  • the electronic devices include, but are not limited to: notebook computers, pen-input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, head-mounted Stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles , bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries or lithium-ion capacitors, etc.
  • Step (1) Combine inorganic particles (boehmite, mass percentage 90.9%), first conductive agent (SP, mass percentage 1%), first binder ((40% acrylonitrile + 45% sodium acrylate + 15 % acrylamide) polymer, mass percentage 8%), and leveling agent (polydimethylsilane, mass percentage 0.1%), add water and mix evenly to obtain the slurry of the protective layer (hereinafter referred to as "first slurry”). material”);
  • Step (2) Coating the first slurry in step (1) on the target area of the positive electrode current collector;
  • Step (3) drying the positive electrode current collector containing the first slurry obtained in step (2) to remove the solvent to obtain a positive electrode current collector coated with a protective layer;
  • Step (4) Combine the active material (lithium cobalt oxide, 97.3% by mass), the third conductive agent (0.6% by mass of conductive carbon (trade name Super P) and 0.5% by mass of carbon nanotubes (abbreviated as CNT) , the third binder (polyvinylidene fluoride (abbreviated as PVDF) with a mass percentage of 1.6%) is dispersed in the solvent system and stirred thoroughly to obtain a slurry of the positive electrode active material (hereinafter referred to as the "second slurry” );
  • Step (5) applying the second slurry to the target area of the positive electrode current collector coated with the protective layer obtained in step (3);
  • Step (6) Drying the positive electrode current collector containing the second slurry in step (5) to remove the solvent, thereby obtaining the desired positive electrode.
  • the positive electrode of the electrochemical device was fabricated as described above.
  • Negative electrode Combine the active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (abbreviated as SBR), and thickener sodium carboxymethylcellulose (abbreviated as CMC) in a mass ratio of 95:2:2:1 After thoroughly stirring and mixing in water, it is coated on Cu foil, dried, and cold pressed to obtain a negative electrode.
  • SBR binder styrene-butadiene rubber
  • CMC thickener sodium carboxymethylcellulose
  • Electrolyte In an argon atmosphere glove box with a water content of ⁇ 10 ppm, mix ethylene carbonate (abbreviated as EC), diethyl carbonate (abbreviated as DEC), and propylene carbonate (abbreviated as PC) according to 2:6: Mix evenly at a weight ratio of 2, then dissolve the fully dried lithium salt LiPF6 in the above solvent, and then add 1,3-propane sultone, fluoroethylene carbonate and adiponitrile. After mixing, the content of LiPF6 is 12.5%, the content of 1,3-propane sultone is 1.5%, the content of fluoroethylene carbonate is 3%, and the content of adiponitrile is 2%. Among them, the content of each substance is Based on the total weight of electrolyte.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • PC propylene carbonate
  • Isolation film Polyethylene (abbreviated as PE) porous polymer film is used as the isolation film.
  • the coverage of the first protective layer on the first surface of the current collector A3/(A1+A2), the relative proportion of the second area to the first area A2/A1, the coverage of the first protective layer on the first area B1/A1,
  • the coverage of the first protective layer on the second area is B2/A2
  • the coverage of the second protective layer on the third area is C1/A1
  • the coverage of the second protective layer on the fourth area is C2/A2.
  • the resistance test parameters are: pressure head area 153.94mm2, pressure 3.5t, holding time 50s.
  • the lithium-ion battery to be tested is charged with a constant current at a rate of 0.05C to the full charge design voltage of 4.45V, and then charged with a constant voltage of the full charge design voltage of 4.45V until the current is 0.025C (cut-off current), so that the lithium-ion battery reaches full charge.
  • Charging status record the appearance of the lithium-ion battery before testing.
  • the passing criterion is that the lithium-ion batteries do not burn or explode.
  • the pass rate of center nailing the number of passes/20.
  • Table 1 specifically shows the differences in protective layer coating and corresponding lithium ion battery performance in Examples 1 to 30 and Comparative Examples 1 to 2.
  • the coverage degree of the first protective layer on the first surface is A3/(A1+A2) (where A3 is the area of the first protective layer; A1 is the area with the positive active material layer above the first surface; A2 is the area without the positive active material layer above the first surface) is controlled to be greater than or equal to 50%, and it can maintain the same performance as the uncoated first surface.
  • the protective layer of the lithium-ion battery provides significantly improved center penetration rate at comparable discharge rates.
  • the first surface of the positive electrode current collector can be fully protected by the first protective layer, and the first protective layer can insulate it during impact or puncture by external force.
  • the positive electrode current collector and the negative electrode active material layer are connected, thereby suppressing the most dangerous short circuit between the positive electrode current collector and the negative electrode active material layer, and improving the safety performance of the electrochemical device.
  • the resistance R1 of the positive electrode in the first area is ⁇ 3 ⁇ , which can provide a higher contact resistance at the puncture point, thereby reducing the short-circuit current and reducing the heat generated by the battery, thus improving the center penetration of the lithium-ion battery. Rate.
  • Example 1 in Table 1 it can be seen from the comparison between Example 1 in Table 1 and Examples 7 to 17 that when the positive electrode further satisfies 0.8 ⁇ B1/A1 ⁇ 1 and 0.5 ⁇ B2/A2 ⁇ 1, the center hole of the corresponding lithium ion battery The nail pass rate can be further improved. This is because when the puncture object pierces the first region, if a short circuit occurs between the positive electrode current collector and the negative electrode active material layer, since the positive electrode active material layer is provided on the first area, the electron conduction path is shorter and the electron conduction path is shorter. The short-circuit current will be too large and fire or explosion will easily occur.
  • the first area of the positive electrode current collector can be fully protected by the first protective layer, inhibiting the activity of the positive electrode current collector and the negative electrode in the first area.
  • the occurrence of short circuit between the material layers will improve the central nail penetration rate of the lithium-ion battery; when 0.5 ⁇ B2/A2 ⁇ 1 is satisfied, the second area can be fully protected by the first protective layer, inhibiting the positive electrode collection in the second area.
  • the occurrence of a short circuit between the fluid and the negative active material layer can further improve the safety performance of the electrochemical device.
  • references throughout this specification to “some embodiments,” “partial embodiments,” “one embodiment,” “another example,” “example,” “specific example,” or “partial example” mean the following: At least one embodiment or example in this application includes a specific feature, structure, material or characteristic described in the embodiment or example. Accordingly, phrases such as “in some embodiments,” “in an embodiment,” “in one embodiment,” “in another example,” “in one example,” etc. may appear in various places throughout this specification. "in”, “in a particular example” or “for example” do not necessarily refer to the same embodiment or example in this application. Furthermore, the specific features, structures, materials, or characteristics herein may be combined in any suitable manner in one or more embodiments or examples.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Cell Electrode Carriers And Collectors (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)

Abstract

本申请涉及一种电化学装置，其包括正极，所述正极包括正极集流体、第一保护层和第一正极活性材料层。所述正极集流体包括相对的第一表面和第二表面，所述第一保护层设置于所述第一表面与所述第一正极活性材料层之间。其中，所述第一表面包含第一区域和第二区域，所述第一区域上设有所述第一正极活性材料层，所述第二区域上未设有所述第一正极活性材料层。所述第一区域的面积为A1cm 2，所述第二区域的面积为A2cm 2，所述第一保护层的面积为A3cm 2，通过满足：0.5≤A3/(A1+A2)≤1，本申请的电化学装置具有显著提升的安全性能。

Description

一种包含保护层的电化学装置及电子装置 技术领域
本申请涉及储能领域，具体涉及一种包含保护层的电化学装置及电子装置。
背景技术
随着电子产品如笔记本电脑、手机、掌上游戏机和平板电脑等的普及，人们对电化学装置(例如，锂离子电池)的安全性要求也越来越高。然而，目前锂离子电池在使用过程中，仍然存在由于外力撞击或穿刺等原因造成的着火、爆炸等安全事故，限制了锂离子电池的广泛应用。其中，正极集流体(如铝箔)与负极活性材料层之间的短路是最容易导致安全事故的一种。因此，亟需一种能够改善锂离子电池安全性能的技术手段。
发明内容
根据本申请的一方面，本申请提供一种电化学装置，其包括正极，所述正极包括正极集流体、第一保护层和第一正极活性材料层。所述正极集流体包括相对的第一表面和第二表面。所述第一保护层设置于所述第一表面与所述第一正极活性材料层之间。所述第一表面包含第一区域和第二区域，所述第一区域上设有所述第一正极活性材料层，所述第二区域上未设有所述第一正极活性材料层。所述第一区域的面积为A1cm 2，所述第二区域的面积为A2cm 2，所述第一保护层的面积为A3cm 2，满足：0.5≤A3/(A1+A2)≤1。通过满足0.5≤A3/(A1+A2)≤1，正极集流体的第一表面能够得到第一保护层充分的保护，在受到外力撞击或穿刺的过程中，第一保护层能够隔绝正极集流体与负极活性材料层之间的导通，从而抑制最危险的正极集流体与负极活性材料层之间短路的发生，提高电化学装置的安全性能。
在一些实施例中，所述正极为卷绕结构，所述卷绕结构包括位于所述卷绕结构内侧的卷绕起始端和位于所述卷绕结构外侧的卷绕末端，所述第二区域位于所述卷 绕末端，且0＜A2/A1≤0.2。此时，第二区域位于卷绕结构的外侧，在受到外力撞击或穿刺的过程中，即使第二区域发生短路，由于其表面无正极活性材料层，其电子传导路径较长，能够降低短路电流，从而降低电化学装置发生着火、爆炸的风险。
在一些实施例中，所述第一区域上的所述第一保护层的面积为B1cm2，满足：0.8≤B1/A1≤1。当穿刺物刺穿第一区域时，若发生正极集流体与负极活性材料层之间的短路，由于第一区域上设有正极活性材料层，此时电子传导路径较短，瞬时短路电流将过大，容易发生着火、爆炸，通过满足0.8≤B1/A1≤1，正极集流体的第一区域能够获得第一保护层充分地保护，抑制第一区域处正极集流体与负极活性材料层之间短路的发生，从而提高电化学装置的安全性能。
在一些实施例中，所述第二区域上的所述保护层的面积为B2cm2，其中满足0.5≤B2/A2≤1。此时，第二区域能够获得第一保护层充分地保护，抑制第二区域处正极集流体与负极活性材料层之间短路的发生，从而提高电化学装置的安全性能。
在一些实施例中，所述正极还包括第二正极活性材料层和位于所述第二表面与所述第二正极活性材料层之间的第二保护层；所述第二表面包括与所述第一区域相对的第三区域和与所述第二区域相对的第四区域；所述第三区域上的所述第二保护层的面积为C1，所述第四区域上的所述第二保护层的面积为C2，满足：0.8≤C1/A1≤1，和/或0.5≤C2/A2≤1。此时，第二区域和/或第四区域均能够获得第二保护层的充分保护，降低在穿刺过程中，正极集流体刺穿处的第二表面形成毛刺刺穿隔膜，导致发生最危险的正极集流体与负极活性材料层之间短路的风险，从而提高电化学装置的安全性能。
在一些实施例中，所述电化学装置在满充状态下，所述正极在所述第一区域的电阻值为R1，所述正极在所述第二区域的电阻值为R2，满足：1.5≤R1≤10.5；和/或1≤R2≤10。此时，电化学装置能够兼具优异的电化学性能和安全性能。
在一些实施例中，所述第一保护层包含第一无机颗粒、第一粘结剂和第一导电剂。
在一些实施例中，所述第二保护层包含第二无机颗粒、第二粘结剂和第二导电剂。
在一些实施例中，所述第一粘结剂和/或所述第二粘结剂满足如下特征中的至少一者：(1)包含丙烯酸、丙烯酰胺、丙烯酸盐、丙烯腈或丙烯酸酯中的至少一种形成的聚合物；(2)包含羧甲基纤维素盐或丁腈橡胶中的至少一者。
在一些实施例中，所述第一粘结剂和/或所述第二粘结剂为水性粘结剂。
在一些实施例中，所述第一无机颗粒和/或所述第二无机颗粒包含氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙、硬水铝石、硫酸钡、硫酸钙或硅酸钙中的至少一种。
在一些实施例中，所述第一导电剂和/或所述第二导电剂包含片层状、网状、线状或颗粒状导电剂中的至少一种。
在一些实施例中，基于所述第一保护层的质量，所述第一无机颗粒的质量百分比为60％至99％。在一些实施例中，基于所述第一保护层的质量，所述第一粘结剂的质量百分比为0.5％至22％。在一些实施例中，基于所述第一保护层的质量，所述第一导电剂的质量百分比为0.1％至11％。
在一些实施例中，基于所述第二保护层的质量，所述第二无机颗粒的质量百分比为60％至99％。在一些实施例中，基于所述第二保护层的质量，所述第二粘结剂的质量百分比为0.5％至22％。在一些实施例中，基于所述第二保护层的质量，所述第二导电剂的质量百分比为0.1％至11％。
在一些实施例中，所述第一保护层还包含第一流平剂；和/或所述第二保护层还包含第二流平剂。
在一些实施例中，基于所述第一保护层的质量，所述第一流平剂的质量百分比为大于0％且小于或者等于5％。在一些实施例中，基于所述第二保护层的质量，所述第二流平剂的质量百分比为大于0％且小于或者等于5％。
在一些实施例中，所述第一流平剂和/或所述第二流平剂包括硅氧烷类化合物、硅氧烷类衍生物、含氧烯烃聚合物、羧酸酯类化合物、羧酸盐类化合物、 醇类化合物、醚类化合物或氟碳化合物中的至少一种。
根据本申请的另一方面，本申请涉及包含根据前述任一实施例所述的电化学装置的电子装置。
附图说明
图1显示根据本申请的一些实施例的用于电化学装置的正极。
图2显示根据本申请的一些实施例的用于电化学装置的正极。
图3显示根据本申请的一些实施例的用于电化学装置的正极。
具体实施方式
下文中，对本申请进行详细说明。应当理解，在说明书和所附权利要求中使用的术语不应被解释为限于一般和词典的含义，而是在发明人被允许适当定义术语以进行最佳解释的原则的基础上基于与本申请的技术方面相对应的含义和概念来解释。因此，说明书中所述的实施方案中所示的描述仅仅是用于说明的目的的具体实例，而不旨在显示本申请的所有技术方面，并且应当理解，在提交本申请时可以对其完成多种可选等价体和变体。
在具体实施方式及权利要求书中，由术语“和/或”所连接的项目的列表可意味着包括一个或多个相关的所列项目的任意的和所有的组合。例如，如果列出项目A及B，那么短语“A和/或B”意味着仅A；仅B；或A及B。在具体实施方式及权利要求书中，由术语“中的至少一者”、“中的至少一个”、“中的至少一种”或其他相似术语所连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个组件或多个组件。项目B可包含单个组件或多个组件。项目C可包含单个组件或多个组件。
另外，有时在本文中以范围格式呈现量、比率和其它数值。应理解，此类范围格式是用于便利及简洁起见，且应灵活地理解，不仅包含明确地指定为范围限制的 数值，而且包含涵盖于所述范围内的所有个别数值或子范围，如同明确地指定每一数值及子范围一般。
一、电化学装置
图1显示根据本申请的一些实施例的用于电化学装置的正极10。所述正极10包括正极集流体12、第一保护层14a、第二保护层14b、第一正极活性材料层16a和第二正极活性材料层16b。所述正极集流体包括相对的第一表面12a和第二表面12b。所述第一保护层14a设置于所述第一表面12a与所述第一正极活性材料层16a之间。所述第二保护层14b设置于所述第二表面12b与所述第二正极活性材料层16b之间。所述第一表面12a包含第一区域18a和第二区域18b，所述第一区域18a上设有所述第一正极活性材料层16a，所述第二区域18b上未设有所述第一正极活性材料层16a。
在一些实施例中，所述第一区域18a的面积为A1cm2，所述第二区域18b的面积为A2cm2，所述第一保护层14a的面积为A3cm2，满足：0.5≤A3/(A1+A2)≤1。通过满足0.5≤A3/(A1+A2)≤1，正极集流体12的第一表面12a能够得到第一保护层14a的充分保护，在受到外力撞击或穿刺过程中，第一保护层14a能够隔绝正极集流体12与负极活性材料层的导通，从而抑制最危险的正极集流体与负极活性材料层之间短路的发生，提高电化学装置的安全性能。在图1显示的实施例中，A3/(A1+A2)等于1。
在一些实施例中，0.5≤A3/(A1+A2)≤1。在一些实施例中，0.8≤A3/(A1+A2)≤1。在一些实施例中，A3/(A1+A2)为0.5、0.55、0.6、0.65、0.7、0.75、0.8、0.85、0.9、0.95、1或前述任意两数值之间的范围。
在一些实施例中，所述正极为卷绕结构，所述卷绕结构包括位于所述卷绕结构内侧的卷绕起始端和位于所述卷绕结构外侧的卷绕末端，所述第二区域18b位于所述卷绕末端，且0＜A2/A1≤0.2。此时，第二区域18b位于卷绕结构的外侧，在受到外力撞击或穿刺过程中，即使第二区域18b发生短路，由于其表面无正极活性材料层，其电子传导路径较长，能够降低短路电流，从而降低电化学装置发生着火、爆 炸的风险。在一些实施例中，A2/A1为0.01、0.02、0.03、0.04、0.05、0.06、0.07、0.08、0.09、0.1、0.12、0.14、0.16、0.18、0.2或前述任意两数值之间的范围。
在一些实施例中，所述第一区域18a上的所述第一保护层14a的面积为B1cm2，满足：0.5≤B1/A1≤1。在一些实施例中，0.8≤B1/A1≤1。在一些实施例中，B1/A1为0.5、0.55、0.6、0.65、0.7、0.75、0.8、0.85、0.9、0.95、1或前述任意两数值之间的范围。当穿刺物刺穿第一区域18a时，若发生正极集流体与负极活性材料层之间的短路，由于第一区域18a上设有第一正极活性材料层16a，此时电子传导路径较短，瞬时短路电流将过大，容易发生着火、爆炸，通过满足0.5≤B1/A1≤1，正极集流体的第一区域18a能够获得第一保护层14a的充分保护，抑制第一区域18a处正极集流体与负极活性材料层之间短路的发生，从而提高电化学装置的安全性能。
在一些实施例中，所述第二区域18b上的所述保护层14a的面积为B2cm 2，满足：0.5≤B2/A2≤1。在一些实施例中，B2/A2为0.5、0.55、0.6、0.65、0.7、0.75、0.8、0.85、0.9、0.95、1或前述任意两数值之间的范围。此时，第二区域18b能够获得第一保护层的充分保护，抑制第二区域18b处正极集流体与负极活性材料层之间短路的发生，从而提高电化学装置的安全性能。
在一些实施例中，所述第二表面12b包括与所述第一区域18a相对的第三区域19a和与所述第二区域18b相对的第四区域19b；所述第三区域19a上的所述第二保护层16b的面积为C1，满足：0.5≤C1/A1≤1。在一些实施例中，C1/A1为0.5、0.55、0.6、0.65、0.7、0.75、0.8、0.85、0.9、0.95、1或前述任意两数值之间的范围。
在一些实施例中，所述第四区域19b上的所述第二保护层16b的面积为C2，满足：0.5≤C2/A2≤1。在一些实施例中，C2/A2为0.5、0.55、0.6、0.65、0.7、0.75、0.8、0.85、0.9、0.95、1或前述任意两数值之间的范围。
此时，第三区域19a和/或第四区域19b能够获得第二保护层16b的充分保护，降低在穿刺过程中，正极集流体刺穿处的第二表面12b形成的毛刺刺穿隔膜，导致发生最危险的正极集流体与负极活性材料层之间短路的风险，从而提高 电化学装置的安全性能。
图2显示根据本申请的一些实施例的用于电化学装置的正极20。图2显示的正极20与图1显示者不同之处包括图2的正极20中的集流体12的第二表面12b中与第二区域18b相对的第四区域19b上的部分未被第二保护层14b覆盖。
图3显示根据本申请的一些实施例的用于电化学装置的正极30。图3显示的正极30与图1显示者不同之处包括图3的正极30中的集流体12的第一表面12a中第二区域18b上的全部未被第一保护层34a覆盖。
在一些实施例中，所述电化学装置在满充状态下，所述正极在所述第一区域18a的电阻值为R1Ω2，1.5≤R1≤10.5。在一些实施例中，R1为1.5、2、2.5、3、3.5、4、4.5、5、5.5、6、6.5、7、7.5、8、8.5、9、9.5、10、10.5或前述任意两数值之间的范围。此时，电化学装置能够兼具优异的电化学性能和安全性能。
在一些实施例中，所述正极在所述第二区域18b的电阻值为R2Ω2，1≤R2≤10。在一些实施例中，R1为1、1.5、2、2.5、3、3.5、4、4.5、5、5.5、6、6.5、7、7.5、8、8.5、9、9.5、10或前述任意两数值之间的范围。此时，电化学装置能够具有优异的安全性能。
在一些实施例中，第一保护层包含第一无机颗粒、第一粘结剂和第一导电剂。
在一些实施例中，第二保护层包含第二无机颗粒、第二粘结剂和第二导电剂。
在一些实施例中，第一无机颗粒和/或第二无机颗粒包含氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石(软水铝石)、氢氧化铝、氢氧化镁、氢氧化钙、硬水铝石、硫酸钡、硫酸钙或硅酸钙中的至少一种。
在一些实施例中，基于第一保护层的质量，第一无机颗粒的质量百分比为60％至99％。在一些实施例中，第一无机颗粒的质量百分比为60％、65％、70％、75％、80％、85％、90％、95％、99％或前述任意两数值之间的范围。
在一些实施例中，基于第二保护层的质量，第二无机颗粒的质量百分比为60％ 至99％。在一些实施例中，第二无机颗粒的质量百分比为60％、65％、70％、75％、80％、85％、90％、95％、99％或前述任意两数值之间的范围。
在一些实施例中，第一粘结剂包含丙烯酸、丙烯酰胺、丙烯酸盐、丙烯腈或丙烯酸酯中的至少一种形成的聚合物。
在一些实施例中，第一粘结剂包含羧甲基纤维素盐或丁腈橡胶中的至少一者。
在一些实施例中，第二粘结剂包含丙烯酸、丙烯酰胺、丙烯酸盐、丙烯腈或丙烯酸酯中的至少一种形成的聚合物。
在一些实施例中，第二粘结剂包含羧甲基纤维素盐或丁腈橡胶中的至少一者。
在一些实施例中，所述第一粘结剂为水性粘结剂。在一些实施例中，所述第二粘结剂为水性粘结剂。此时，第一粘结剂和/或第二粘结剂具有较好的亲水疏油性，使得第一保护层和/或第二保护层在油性电解液中具有优异的粘结性和稳定性，进而可以提高电化学装置的安全性能。
在一些实施例中，基于第一保护层的质量，第一粘结剂的质量百分比为0.5％至22％。在一些实施例中，基于第一保护层的质量，第一粘结剂的质量百分比为5％至15％。在一些实施例中，第一粘结剂的质量百分比为0.5％、1％、2％、3％、4％、5％、6％、7％、8％、9％、10％、11％、12％、13％、14％、15％、16％、17％、18％、19％、20％、21％、22％或前述任意两数值之间的范围。在一些实施例中，基于第二保护层的质量，第二粘结剂的质量百分比为0.5％至22％。在一些实施例中，第二粘结剂的质量百分比为0.5％、1％、2％、3％、4％、5％、6％、7％、8％、9％、10％、11％、12％、13％、14％、15％、16％、17％、18％、19％、20％、21％、22％或前述任意两数值之间的范围。通过调节粘结剂在保护层中的质量百分比，可以保证正极活性材料层、保护层和集流体之间的较好的结合力，减少在异常情况下的正极活性材料层的松动乃至脱落，从而可以改善电化学装置的穿钉安全性能和电化学性能。
在一些实施例中，所述第一导电剂和/或第二导电剂包含片层状、网状、线状或颗粒状导电剂中的至少一种。在一些实施例中，所述第一导电剂和/或第二导电剂包含石墨烯(简写为GN)、石墨纤维、碳纳米管(简写为CNT)、科琴黑或导电碳(简 写为SP)中的至少一种。
在一些实施例中，基于第一保护层的质量，第一导电剂的质量百分比为0.1％至11％。在一些实施例中，第一导电剂的质量百分比为0.1％、0.4％、0.6％、0.8％、1％、1.6％、1.8％、2％、3％、4％、5％、6％、7％、9％、10％、11％或前述任意两数值之间的范围。在一些实施例中，基于第二保护层的质量，第二导电剂的质量百分比为0.1％至11％。在一些实施例中，第二导电剂的质量百分比为0.1％、0.4％、0.6％、0.8％、1％、1.6％、1.8％、2％、3％、4％、5％、6％、7％、9％、10％、11％或前述任意两数值之间的范围。
在一些实施例中，第一保护层还包含第一流平剂。在一些实施例中，所述第二保护层还包含第二流平剂。在一些实施例中，所述第一流平剂和/或第二流平剂包括硅氧烷类化合物、硅氧烷类衍生物、含氧烯烃聚合物、羧酸酯类化合物、羧酸盐类化合物、醇类化合物、醚类化合物或氟碳化合物中的至少一种。在一些实施例中，基于第一保护层的质量，第一流平剂的质量百分比为大于0％且小于或者等于5％。在一些实施例中，第一流平剂的质量百分比为0.001％、0.01％、0.02％、0.03％、0.04％、0.05％、0.06％、0.07％、0.08％、0.09％、0.1％、0.2％、0.3％、0.4％、0.5％、1％、1.5％、2％、2.5％、3％、3.5％、4％、4.5％、5％或前述任意两数值之间的范围。在一些实施例中，基于第二保护层的质量，第二流平剂的质量百分比为大于0％且小于或者等于5％。在一些实施例中，第二流平剂的质量百分比为0.001％、0.01％、0.02％、0.03％、0.04％、0.05％、0.06％、0.07％、0.08％、0.09％、0.1％、0.2％、0.3％、0.4％、0.5％、1％、1.5％、2％、2.5％、3％、3.5％、4％、4.5％、5％或前述任意两数值之间的范围。流平剂的加入，有利于形成均匀、平滑的保护层，增加保护层和集流体以及正极活性材料层的接触面积，提高电化学装置的安全性能。
在一些实施例中，所述正极活性材料层包含活性物质、第三粘结剂和第三导电剂。
在一些实施例中，活性物质包含钴酸锂(简写为LCO)。在一些实施例中，基于正极活性材料层的质量，活性物质的质量百分比为94％至99％。在一些实施例中，基于正极活性材料层的质量，活性物质的质量百分比为94％、94.5％、95％、95.5％、 96％、96.5％、97％、97.5％、98％、98.5％、99％或前述任意两数值之间的范围。
在一些实施例中，第三粘结剂包含聚偏氟乙烯(简写为PVDF)、丁腈橡胶或聚丙烯酸酯中的至少一种。在一些实施例中，基于正极活性材料层的质量，第三粘结剂的质量百分比为0.5％至2.5％。在一些实施例中，基于正极活性材料层的质量，第三粘结剂的质量百分比为0.5％、1％、1.5％、2％、2.5％或前述任意两数值之间的范围。
在一些实施例中，第三导电剂包含石墨烯、石墨纤维、碳纳米管、科琴黑或导电碳中的至少一种。在一些实施例中，基于正极活性材料层的质量，第三导电剂的质量百分比为0.5％至3.5％。在一些实施例中，基于正极活性材料层的质量，第三导电剂的质量百分比为0.5％、1％、1.5％、2％、2.5％、3％、3.5％或前述任意两数值之间的范围。
本申请通过在电化学装置的正极集流体与正极活性材料层之间设置保护层，并控制保护层对集流体的覆盖度能够提高电化学装置在受到外力撞击或穿刺过程中的安全性；同时，也能简化保护层的施加方式，提高加工效率。
本申请的电化学装置还包括隔离膜、电解液和负极。
在一些实施例中，本申请的电化学装置包括一次电池或二次电池。在一些实施例中，所述电化学装置是锂二次电池。在一些实施例中，锂二次电池包括，但不限于：锂金属二次电池、锂离子二次电池、锂聚合物二次电池或锂离子聚合物二次电池。
二、一种制备前述电化学装置的方法
如下以锂离子电池为例详细描述了本申请的电化学装置的制备方法。
负极的制备：将负极活性物质(碳材料、硅材料或钛酸锂中的至少一种)和负极粘结剂，以及可选的导电材料，按一定的质量比分散于溶剂体系中充分搅拌混合均匀后，涂覆于负极集流体上，经过烘干、冷压，得到负极。
正极的制备：(1)将无机颗粒、第一导电剂、第一粘结剂，以及可选的流 平剂，加入溶剂中混合均匀，获得保护层的浆料(在后称作“第一浆料”)；(2)将步骤(1)中的第一浆料涂覆在正极集流体的目标区域；(3)将步骤(2)中的获得的含有第一浆料的正极集流体进行烘干以去除溶剂，得到涂有保护层的正极集流体；(4)将活性物质、第三导电剂、第三粘结剂按一定的质量比分散于溶剂体系中充分搅拌混合均匀，得到正极活性物质的浆料(在后称作“第二浆料”)；(5)将第二浆料涂覆在步骤(3)中得到的涂有保护层的正极集流体的目标区域；(6)将步骤(5)中的含有第二浆料的正极集流体进行烘干以去除溶剂，从而得到所要正极。
无机颗粒、第一导电剂、第一粘结剂、活性物质、第三导电剂和第三粘结剂的种类如前述。
在一些实施例中，所述溶剂的示例包括但不限于N-甲基吡咯烷酮、丙酮或水。在一些实施例中，可适当的调节溶剂的量。
在一些实施例中，所述集流体具有3微米至20微米范围内的厚度，但本公开内容不限于此。所述集流体没有特别的限制，只要所述集流体是导电的，而不在所制造的电池中引起不利的化学变化。所述集流体的实施例包括铜、不锈钢、铝、镍、钛或合金(例如同-镍合金)，但公开内容不限于此。在一些实施例中，所述集流体的表面上可包括细小的不规则物(例如，表面粗糙度)以增强所述集流体的表面对活性物质的粘合。在一些实施例中，集流体可以多种形式使用，其实施例包括膜、片、箔、网、多孔结构体、泡沫体或无妨物，但本公开内容不限于此。
隔离膜：在一些实施例中，以聚乙烯(简写为PE)多孔聚合薄膜作为隔离膜。在一些实施例中，所述隔离膜的材质可包括玻璃纤维，聚酯，聚乙烯，聚丙烯，聚四氟乙烯或其组合。在一些实施例中，所述隔离膜中的孔具有在0.01微米至1微米范围的直径，所述隔离膜的厚度在5微米至500微米范围内。
电解液：在一些实施例中，所述电解液包括有机溶剂、锂盐和添加剂。在一些实施例中，有机溶剂包括碳酸乙烯酯(简写为EC)、碳酸丙烯酯(简写为 PC)、碳酸二乙酯(简写为DEC)、碳酸甲乙酯(简写为EMC)、碳酸二甲酯(简写为DMC)、碳酸亚丙酯或丙酸乙酯中的至少一种。在一些实施例中，锂盐包括有机锂盐或无机锂盐中的至少一种。在一些实施例中，锂盐包括六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、二氟磷酸锂(LiPO 2F 2)、双三氟甲烷磺酰亚胺锂LiN(CF 38O 2) 2(LiTFSI)、双(氟磺酰)亚胺锂Li(N(SO 2F) 2)(LiFSI)、双草酸硼酸锂LiB(C 2O 4) 2(LiBOB)或二氟草酸硼酸锂LiBF 2(C 2O 4)(LiDFOB)中的至少一种。
将正极、隔离膜、负极按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕得到裸电芯。将经卷绕所得裸电芯置于外包装中，注入电解液并封装，经过化成、脱气、切边等工艺流程获得锂离子电池。
三、电子装置
本申请提供了一种电子装置，其包含根据前述内容所述的电化学装置。
根据本申请的一些实施例，所述电子装置包括，但不限于：笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池或锂离子电容器等。
四、具体的实施例
下面结合实施例，对本申请做进一步详细的描述。然而，应理解，以下实施例仅是示例，本申请的实施例方式不限于此。
实施例1至30和对比例1至2
正极的制作
步骤(1)：将无机颗粒(勃姆石，质量百分比90.9％)、第一导电剂(SP，质量百分比1％)、第一粘结剂((40％丙烯腈+45％丙烯酸钠+15％丙烯酰胺)聚合物， 质量百分比8％)，以及流平剂(聚二甲基硅烷，质量百分比0.1％)，加入水中混合均匀，获得保护层的浆料(在后称作“第一浆料”)；
步骤(2)将步骤(1)中的第一浆料涂覆在正极集流体的目标区域；
步骤(3)将步骤(2)中的获得的含有第一浆料的正极集流体进行烘干以去除溶剂，得到涂有保护层的正极集流体；
步骤(4)将活性物质(钴酸锂，质量百分比97.3％)、第三导电剂(质量百分比0.6％的导电碳(商品名Super P)和质量百分比0.5％的碳纳米管(简写为CNT)、第三粘结剂(质量百分比1.6％的聚偏氟乙烯(简写为PVDF))分散于溶剂体系中充分搅拌混合均匀，得到正极活性物质的浆料(在后称作“第二浆料”)；
步骤(5)将第二浆料涂覆在步骤(3)中得到的涂有保护层的正极集流体的目标区域；
步骤(6)将步骤(5)中的含有第二浆料的正极集流体进行烘干以去除溶剂，从而得到所要正极。
电化学装置的制作
电化学装置的正极的制作如前述。
负极：将活性物质人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(简写为SBR)、增稠剂羧甲基纤维素钠(简写为CMC)按照质量比为95∶2∶2∶1在水中充分搅拌混合均匀后，涂覆于Cu箔上烘干、冷压，得到负极。
电解液：在含水量＜10ppm的氩气气氛手套箱中，将碳酸乙烯酯(简写为EC)、碳酸二乙酯(简写为DEC)、碳酸丙烯酯(简写为PC)、按照2∶6∶2的重量比混合均匀，再将充分干燥的锂盐LiPF6溶解于上述溶剂，之后加入1，3-丙烷磺内酯、氟代碳酸乙烯酯和己二腈。混合后，LiPF6的含量为12.5％、1，3-丙烷磺内酯的含量为1.5％、氟代碳酸乙烯酯的含量为3％、己二腈的含量为2％，其中，各物质含量是以电解液的总重量计。
隔离膜：以聚乙烯(简写为PE)多孔聚合薄膜作为隔离膜。
将正极、隔离膜、负极按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕、置于外包装中，注入配好的电解液并封装，经过化成，脱气，切边等工艺得到锂离子电池。
性能测试方法
第一保护层对集流体第一表面的覆盖度A3/(A1+A2)、第二区域与第一区域相对占比A2/A1、第一保护层对第一区域的覆盖度B1/A1、第一保护层对第二区域的覆盖度B2/A2、第二保护层对第三区域的覆盖度C1/A1、第二保护层对第四区域的覆盖度C2/A2
1)在(25±3)℃的环境下，将涂有保护层的正极极片从锂离子电池中拆出，用无尘纸拭去正极极片表面残留的电解液。
2)测量正极集流体第一表面上涂覆正极活性材料层的第一区域的面积为A1cm 2、未涂覆正极活性材料层的第二区域的面积为A2cm 2。
3)将正极极片浸泡在氮甲基吡咯烷酮(NMP)中，洗去正极极片表面的正极活性材料层，测量正极集流体第一表面上第一保护层的面积为A3cm 2，第一区域上的第一保护层的面积为B1cm 2，第二区域上的第一保护层的面积为B2cm 2，与第一区域相对的第三区域上第二保护层的面积为C1cm 2，与第三区域相对的第四区域上的第二保护层的面积为C2cm 2。
4)计算即可获得相应的A3/(A1+A2)、A2/A1、B1/A1、B2/A2、C1/A1、C2/A2。
满充状态下的正极电阻
1)0.05C的倍率恒流充电至满充设计电压4.45V，随后以满充设计电压4.45V恒压充电至电流为0.025C(截止电流)，使锂离子电池达到满充状态；
2)将锂离子电池拆解，得到正极；
3)将2)中所得正极在湿度为5％至15％的环境中放置30min，然后密封转移到电阻测试地点；
4)使用BER1200型号膜片电阻测试仪测试3)中所得正极在第一区域的电 阻，至少随机测试15个不同点，记所有测试点的电阻均值为正极在第一区域的电阻R1；
5)使用BER1200型号膜片电阻测试仪测试3)中所得正极在第二区域的电阻，相邻测试点间隔2mm至3mm，至少测试15个不同点，记所有测试点的电阻均值为正极在第二区域的电阻R2。
电阻测试参数为：压头面积153.94mm2，压力3.5t，保持时间50s。
中心穿钉通过率
将待测的锂离子电池以0.05C的倍率恒流充电至满充设计电压4.45V，随后以满充设计电压4.45V恒压充电至电流为0.025C(截止电流)，使锂离子电池达到满充状态，记录测试前锂离子电池外观。在25±3℃环境中对电池进行穿钉测试，钢钉直径4mm，穿刺速度30mm/s，穿钉位置位于锂离子电池几何中心，测试进行3.5min或电极组件表面温度降到50℃以后停止测试，以20个锂离子电池为一组，观察测试过程中锂离子电池状态，以锂离子电池不燃烧、不爆炸为通过标准。中心穿钉通过率＝通过数/20。
2C放电倍率
1)在25±2℃条件下，将锂离子电池以0.5C的倍率恒流放电至3.0V，然后以0.5C的倍率满充至设计电压4.45V，再以设计电压4.45V恒压充电直至电流为0.02C。
2)将1)中锂离子电池静置10min后，以0.2C的倍率放电至3.0V，记录放电容量为C0。
3)将2)中锂离子电池静置5min后，以0.5C的倍率满充至设计电压4.45V，再以设计电压4.45V恒压充电直至电流为0.02C。
4)将3)中锂离子电池静置10min后，以2C的倍率放电至3.0V，记录放电容量为C1。
5)则2C放电倍率为：C1/C0×100％。
下表1具体示出了实施例1至30和对比例1至2中保护层涂覆差异及相应锂 离子电池性能。
表1
Figure PCTCN2022084049-appb-000001
探讨保护层的覆盖程度对电化学装置的性能影响
由前述表1实施例1至6和对比例1至2的比较可知，将第一保护层在第一表面的覆盖程度A3/(A1+A2)(其中，A3是第一保护层的面积；A1是第一表面上方设有正极活性材料层的区域；A2是第一表面上方未设有正极活性材料层的区域)控制在大于或等于50％时，其能在维持与未涂覆第一保护层的锂离子电池相当的放电倍率下，提供显著改善的中心穿钉通过率。这是由于，通过满足0.5＜A3/(A1+A2) ≤1，正极集流体的第一表面能够获得第一保护层充分的保护，在受到外力撞击或穿刺过程中，第一保护层能够隔绝正极集流体与负极活性材料层的导通，从而抑制最危险的正极集流体与负极活性材料层之间短路的发生，提高电化学装置的安全性能。同时，满充状态下，正极在第一区域的电阻R1≥3Ω，能够在穿刺处提供较高的接触电阻，从而降低短路电流，减小电池产热，进而提高锂离子电池的中心穿钉通过率。
另一方面，由前述表1实施例1和和实施例7至17的比较可知，当正极进一步满足0.8≤B1/A1≤1、0.5≤B2/A2≤1时，相应锂离子电池的中心穿钉通过率能够得到进一步改善。这是由于，当穿刺物刺穿第一区域时，若发生正极集流体与负极活性材料层之间的短路，由于第一区域上设有正极活性材料层，此时电子传导路径较短，瞬时短路电流将过大，容易发生着火、爆炸，通过满足0.8≤B1/A1≤1，正极集流体的第一区域能够获得第一保护层充分地保护，抑制第一区域处正极集流体与负极活性材料层之间短路的发生，从而提高锂离子电池的中心穿钉通过率；满足0.5≤B2/A2≤1时，第二区域能够获得第一保护层充分地保护，抑制第二区域处正极集流体与负极活性材料层之间短路的发生，从而能够进一步提高电化学装置的安全性能。
此外，由前述表1实施例20至30的比较可知，满足0.8≤C1/A1≤1和/或0.5≤C2/A2≤1的锂离子电池，其中心穿钉通过率能够得到进一步改善。此时，第三区域和/或第四区域均能够获得第二保护层的充分保护，降低在穿刺过程中，正极集流体刺穿处的第二表面形成毛刺刺穿隔膜，导致发生最危险的正极集流体与负极活性材料层之间短路的风险，从而提高锂离子电池的安全性能。
整个说明书中对“一些实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用，其所代表的意思是在本申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此，在整个说明书中的各处所出现的描述，例如：“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”，“在一个举例中”、“在特定举例中”或“举例“，其不必然是引用本申请中的相同的实施例或示例。此外，本文中的特定特征、结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (12)

  1. 一种电化学装置，其包括正极，所述正极包括：
    正极集流体、第一保护层和第一正极活性材料层；
    所述正极集流体包括相对的第一表面和第二表面；所述第一保护层设置于
    所述第一表面与所述第一正极活性材料层之间；
    其中，所述第一表面包含第一区域和第二区域，所述第一区域上设有所述
    第一正极活性材料层，所述第二区域上未设有所述第一正极活性材料层，
    所述第一区域的面积为A1cm 2，所述第二区域的面积为A2cm 2，所述第一保护层的面积为A3cm 2，满足：0.5≤A3/(A1+A2)≤1。
  2. 根据权利要求1所述的电化学装置，其中，所述正极为卷绕结构，所述卷绕结构包括位于所述卷绕结构内侧的卷绕起始端和位于所述卷绕结构外侧的卷绕末端，所述第二区域位于所述卷绕末端，且0＜A2/A1≤0.2。
  3. 根据权利要求1所述的电化学装置，其中，所述第一区域上的所述第一保护层的面积为B1cm 2，满足：0.8≤B1/A1≤1。
  4. 根据权利要求1所述的电化学装置，其中，所述第二区域上的所述第一保护层的面积为B2cm 2，满足：0.5≤B2/A2≤1。
  5. 根据权利要求1所述的电化学装置，其中，所述正极还包括第二正极活性材料层和位于所述第二表面与所述第二正极活性材料层之间的第二保护层；所述第二表面包括与所述第一区域相对的第三区域和与所述第二区域相对的第四区域；所述第三区域上的所述第二保护层的面积为C1，所述第四区域上的所述第二保护层的面积为C2，满足：0.8≤C1/A1≤1，和/或0.5≤C2/A2≤1。
  6. 根据权利要求1所述的电化学装置，其中，所述电化学装置在满充状态下，所述正极在所述第一区域的电阻值为R1Ω，所述正极在所述第二区域的电阻值为R2Ω，满足：1.5≤R1≤10.5；和/或1≤R2≤10。
  7. 根据权利要求5所述的电化学装置，其中，所述第一保护层包含第一无机颗粒、第一粘结剂和第一导电剂；和/或所述第二保护层包含第二无机颗粒、第二粘结剂和第二导电剂。
  8. 根据权利要求7所述的电化学装置，其中，所述第一粘结剂和/或所述第二粘结剂满足如下特征中的至少一者：
    (1)包含丙烯酸、丙烯酰胺、丙烯酸盐、丙烯腈或丙烯酸酯中的至少一种形成的聚合物；
    (2)包含羧甲基纤维素盐或丁腈橡胶中的至少一者。
  9. 根据权利要求7所述的电化学装置，其中，所述电化学装置满足如下特征中的至少一者：
    (a)所述第一粘结剂和/或所述第二粘结剂为水性粘结剂；
    (b)所述第一无机颗粒和/或所述第二无机颗粒包含氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙、硬水铝石、硫酸钡、硫酸钙或硅酸钙中的至少一种；
    (c)所述第一导电剂和/或所述第二导电剂包含片层状、网状、线状或颗粒状导电剂中的至少一种。
  10. 根据权利要求7所述的电化学装置，其中，所述电化学装置满足如下特征中的至少一者：
    (d)基于所述第一保护层的质量，所述第一无机颗粒的质量百分比为60％至99％；
    (e)基于所述第二保护层的质量，所述第二无机颗粒的质量百分比为60％至99％；
    (f)基于所述第一保护层的质量，所述第一粘结剂的质量百分比为0.5％至22％；
    (g)基于所述第二保护层的质量，所述第二粘结剂的质量百分比为0.5％ 至22％；
    (h)基于所述第一保护层的质量，所述第一导电剂的质量百分比为0.1％至11％；
    (i)基于所述第二保护层的质量，所述第二导电剂的质量百分比为0.1％至11％。
  11. 根据权利要求7所述的电化学装置，其中，所述第一保护层还包含第一流平剂，和/或所述第二保护层还包含第二流平剂，满足如下特征中的至少一者：
    (j)基于所述第一保护层的质量，所述第一流平剂的质量百分比为大于0％且小于或者等于5％；
    (k)基于所述第二保护层的质量，所述第二流平剂的质量百分比为大于0％且小于或者等于5％；
    (l)所述第一流平剂和/或所述第二流平剂包括硅氧烷类化合物、硅氧烷类衍生物、含氧烯烃聚合物、羧酸酯类化合物、羧酸盐类化合物、醇类化合物、醚类化合物或氟碳化合物中的至少一种。
  12. 一种电子装置，其包括根据权利要求1-11中任一项所述的电化学装置。
PCT/CN2022/084049 2022-03-30 2022-03-30 一种包含保护层的电化学装置及电子装置 Ceased WO2023184233A1 (zh)

Priority Applications (6)

Application Number Priority Date Filing Date Title
PCT/CN2022/084049 WO2023184233A1 (zh) 2022-03-30 2022-03-30 一种包含保护层的电化学装置及电子装置
KR1020247029343A KR20240138119A (ko) 2022-03-30 2022-03-30 보호층을 포함하는 전기화학 디바이스와 전자 디바이스
CN202280010565.0A CN116802855A (zh) 2022-03-30 2022-03-30 一种包含保护层的电化学装置及电子装置
EP22934085.6A EP4503203A4 (en) 2022-03-30 2022-03-30 ELECTROCHEMICAL DEVICE INCLUDING A PROTECTIVE LAYER, AND ELECTRONIC DEVICE
JP2024556174A JP2025510735A (ja) 2022-03-30 2022-03-30 保護層を含む電気化学装置及び電子装置
US18/901,099 US20250023058A1 (en) 2022-03-30 2024-09-30 Electrochemical device including protective layer, and electronic device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/084049 WO2023184233A1 (zh) 2022-03-30 2022-03-30 一种包含保护层的电化学装置及电子装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/901,099 Continuation US20250023058A1 (en) 2022-03-30 2024-09-30 Electrochemical device including protective layer, and electronic device

Publications (1)

Publication Number Publication Date
WO2023184233A1 true WO2023184233A1 (zh) 2023-10-05

Family

ID=88045302

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/084049 Ceased WO2023184233A1 (zh) 2022-03-30 2022-03-30 一种包含保护层的电化学装置及电子装置

Country Status (6)

Country Link
US (1) US20250023058A1 (zh)
EP (1) EP4503203A4 (zh)
JP (1) JP2025510735A (zh)
KR (1) KR20240138119A (zh)
CN (1) CN116802855A (zh)
WO (1) WO2023184233A1 (zh)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002203562A (ja) * 2000-12-28 2002-07-19 Toshiba Corp 非水電解質二次電池
CN106025377A (zh) * 2016-08-01 2016-10-12 东莞新能源科技有限公司 一种卷绕式电芯
CN106558676A (zh) * 2017-01-17 2017-04-05 上海长园维安电子线路保护有限公司 具有保护功能的锂电池集流体
CN108511761A (zh) * 2017-04-13 2018-09-07 万向二三股份公司 一种含ptc涂层的集流体及含该集流体的锂离子电池
CN110931800A (zh) * 2019-04-26 2020-03-27 宁德时代新能源科技股份有限公司 一种电池
CN111200114A (zh) * 2018-11-16 2020-05-26 宁德时代新能源科技股份有限公司 一种正极极片及电化学装置

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5294641B2 (ja) * 2008-01-18 2013-09-18 三洋電機株式会社 密閉電池
KR101452878B1 (ko) * 2012-08-29 2014-10-22 쇼와 덴코 가부시키가이샤 축전 디바이스 및 그 제조 방법
CN105470452A (zh) * 2014-09-29 2016-04-06 株式会社杰士汤浅国际 蓄电元件
JP6602130B2 (ja) * 2014-12-26 2019-11-06 パナソニック株式会社 非水電解質二次電池用正極及び非水電解質二次電池
JP6840507B2 (ja) * 2015-12-25 2021-03-10 パナソニック株式会社 非水電解質二次電池用正極及び非水電解質二次電池
US11276860B2 (en) * 2017-03-16 2022-03-15 Panasonic Intellectual Property Management Co., Ltd. Positive electrode for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery
JP7073689B2 (ja) * 2017-11-29 2022-05-24 株式会社Ｇｓユアサ 極板、電極体及び蓄電素子
JP2019117725A (ja) * 2017-12-27 2019-07-18 東洋インキＳｃホールディングス株式会社 導電性組成物、蓄電デバイス用下地層付き集電体、蓄電デバイス用電極及び蓄電デバイス
CN111180665A (zh) * 2019-06-28 2020-05-19 宁德时代新能源科技股份有限公司 一种电极极片和电化学装置
CN113632273B (zh) * 2020-11-27 2022-12-27 东莞新能源科技有限公司 一种电化学装置和电子装置
CA3203824A1 (en) * 2020-12-31 2022-07-07 Xiaoqian Liu Electrochemical device, electronic device and method for manufacturing electrochemical device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002203562A (ja) * 2000-12-28 2002-07-19 Toshiba Corp 非水電解質二次電池
CN106025377A (zh) * 2016-08-01 2016-10-12 东莞新能源科技有限公司 一种卷绕式电芯
CN106558676A (zh) * 2017-01-17 2017-04-05 上海长园维安电子线路保护有限公司 具有保护功能的锂电池集流体
CN108511761A (zh) * 2017-04-13 2018-09-07 万向二三股份公司 一种含ptc涂层的集流体及含该集流体的锂离子电池
CN111200114A (zh) * 2018-11-16 2020-05-26 宁德时代新能源科技股份有限公司 一种正极极片及电化学装置
CN110931800A (zh) * 2019-04-26 2020-03-27 宁德时代新能源科技股份有限公司 一种电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4503203A4 *

Also Published As

Publication number Publication date
KR20240138119A (ko) 2024-09-20
EP4503203A1 (en) 2025-02-05
US20250023058A1 (en) 2025-01-16
EP4503203A4 (en) 2025-12-31
JP2025510735A (ja) 2025-04-15
CN116802855A (zh) 2023-09-22

Similar Documents

Publication Publication Date Title
JP7378605B2 (ja) 負極活物質、電気化学装置及び電子装置
WO2020098671A1 (zh) 一种正极极片及电化学装置
WO2022205165A1 (zh) 一种隔离膜及包含所述隔离膜的电化学装置和电子装置
CN211879509U (zh) 电极极片、电化学装置及包含其的电子装置
JP2013187196A (ja) ポリマーリチウムイオン電池およびそのセパレータ
US20240356076A1 (en) Electrochemical device and electronic device containing same
WO2022205110A1 (zh) 电化学装置和电子装置
CN113241477B (zh) 电化学装置和电子装置
WO2023082036A1 (zh) 集流体及其制备方法、二次电池、电池模块、电池包和用电装置
WO2021189255A1 (zh) 一种电解液及电化学装置
CN115986130A (zh) 一种正极极片、二次电池及用电装置
WO2021196116A1 (zh) 电极极片、电化学装置及包含其的电子装置
WO2022198614A1 (zh) 负极材料及其制备方法、电化学装置及电子装置
CN115552665A (zh) 电极、电化学装置和电子装置
WO2023184230A1 (zh) 一种正极及使用其的电化学装置及电子装置
WO2024138560A1 (zh) 正极极片、电化学装置和电子装置
WO2024031221A1 (zh) 集流体、极片、二次电池、电池模块、电池包和用电装置
CN116111037B (zh) 电化学装置和电子装置
WO2021128206A1 (zh) 一种电解液及电化学装置
CN101091284B (zh) 锂二次电池
WO2024046274A1 (zh) 正极极片、二次电池及用电装置
WO2022198403A1 (zh) 电化学装置和电子装置
WO2023184232A1 (zh) 一种电化学装置及电子装置
CN115472773A (zh) 电化学装置及用电装置
CN115552658A (zh) 电极及其制备方法、电化学装置和电子装置

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 202280010565.0

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22934085

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20247029343

Country of ref document: KR

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2024556174

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 202417082455

Country of ref document: IN

WWE Wipo information: entry into national phase

Ref document number: 2022934085

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2022934085

Country of ref document: EP

Effective date: 20241029