WO2022000314A1 - 一种电化学装置用隔板、电化学装置及电子装置 - Google Patents

一种电化学装置用隔板、电化学装置及电子装置 Download PDF

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Publication number
WO2022000314A1
WO2022000314A1 PCT/CN2020/099432 CN2020099432W WO2022000314A1 WO 2022000314 A1 WO2022000314 A1 WO 2022000314A1 CN 2020099432 W CN2020099432 W CN 2020099432W WO 2022000314 A1 WO2022000314 A1 WO 2022000314A1
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Prior art keywords
separator
electrode assembly
intermediate layer
electrode
layer
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PCT/CN2020/099432
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English (en)
French (fr)
Inventor
张益博
严坤
胡乔舒
张楠
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宁德新能源科技有限公司
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Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to PCT/CN2020/099432 priority Critical patent/WO2022000314A1/zh
Priority to EP20937170.7A priority patent/EP3975329A4/en
Priority to KR1020227039144A priority patent/KR20220156971A/ko
Priority to CN202080099202.XA priority patent/CN115552706A/zh
Priority to JP2021544213A priority patent/JP7280959B2/ja
Priority to CN202180001771.0A priority patent/CN113261151A/zh
Priority to PCT/CN2021/083037 priority patent/WO2022001235A1/zh
Priority to JP2021541676A priority patent/JP7288063B2/ja
Priority to EP21809906.7A priority patent/EP3965215A4/en
Publication of WO2022000314A1 publication Critical patent/WO2022000314A1/zh
Priority to US17/708,512 priority patent/US20220223899A1/en
Priority to US17/708,580 priority patent/US20220223968A1/en

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    • HELECTRICITY
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    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/289Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by spacing elements or positioning means within frames, racks or packs
    • H01M50/293Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by spacing elements or positioning means within frames, racks or packs characterised by the material
    • HELECTRICITY
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    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/449Separators, membranes or diaphragms characterised by the material having a layered structure
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    • H01M50/10Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/116Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
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    • H01M50/191Inorganic material
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    • H01M50/193Organic material
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    • H01M50/198Sealing members characterised by the material characterised by physical properties, e.g. adhesiveness or hardness
    • HELECTRICITY
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    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/411Organic material
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    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/431Inorganic material
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    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46Separators, membranes or diaphragms characterised by their combination with electrodes
    • HELECTRICITY
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    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/471Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
    • H01M50/474Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by their position inside the cells
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    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/471Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
    • H01M50/477Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by their shape
    • HELECTRICITY
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    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/471Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
    • H01M50/48Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by the material
    • H01M50/483Inorganic material
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    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/471Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
    • H01M50/48Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by the material
    • H01M50/486Organic material
    • HELECTRICITY
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    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • HELECTRICITY
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    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/04Construction or manufacture in general
    • H01M10/0431Cells with wound or folded electrodes
    • HELECTRICITY
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    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00Batteries for particular applications
    • H01M2220/20Batteries in motive systems, e.g. vehicle, ship, plane
    • HELECTRICITY
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    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M2220/30Batteries in portable systems, e.g. mobile phone, laptop
    • HELECTRICITY
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    • H01M50/119Metals
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    • H01M50/124Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Definitions

  • the invention relates to the field of batteries, in particular to a separator for an electrochemical device, an electrochemical device and an electronic device.
  • Lithium-ion batteries have many advantages, such as large volume and mass energy density, long cycle life, high nominal voltage, low self-discharge rate, small size, and light weight, and are widely used in the field of consumer electronics. With the rapid development of electric vehicles and mobile electronic devices in recent years, people have higher and higher requirements for battery energy density, safety, cycle performance, etc., and look forward to the emergence of new lithium-ion batteries with comprehensive performance improvements.
  • Li-ion batteries are limited by their inherent electrochemical system, and it is usually difficult for a single battery to operate at more than 5 V.
  • high-voltage application scenarios such as EV (Electric vehicle, electric vehicle), ESS (Energy Storage System, energy storage system) and other application scenarios.
  • EV Electric vehicle, electric vehicle
  • ESS Electronicgy Storage System, energy storage system
  • a plurality of electrode assemblies are usually assembled in series.
  • the conventional liquid electrolyte electrode assembly needs to realize the ionic insulation function of the series cavity in the series structure, to avoid the internal short circuit of the cathode and anode of different potentials under liquid conditions, and also to avoid the decomposition failure of the conventional liquid electrolyte under high voltage.
  • the separator has certain requirements on its mechanical strength, thickness, thermal stability, electrochemical stability and other parameters. Based on this, it is difficult for conventional single base materials to meet the needs of separators for series electrode assemblies, and new separators need to be developed to realize series isolation of single cells.
  • the commonly used methods for preparing separators are as follows: first, compound a layer of sealing material for encapsulation on the surface of the high temperature-resistant dense insulating material; second, modify the surface of the high temperature-resistant dense insulating material so that the insulating material can be The package is directly and tightly bonded to achieve a seal.
  • the separator prepared by the first method in the current technology is generally a multi-layer stack of similar polymer materials, and the overall thickness is relatively large.
  • the material itself is prone to structural damage and poor ion isolation performance under high temperature packaging conditions.
  • For the separator prepared by the second method there are difficulties in reliable packaging between the separator and the outer package, and the specific application is difficult.
  • An object of the present invention is to provide a separator for an electrochemical device, an electrochemical device and an electronic device, so as to improve the packaging reliability of a lithium ion battery.
  • a first aspect of the present invention provides a separator for an electrochemical device, which has ionic insulation and includes an intermediate layer and an encapsulation layer, the encapsulation layer being located on the upper and lower surfaces of the intermediate layer;
  • the material of the intermediate layer includes at least one of carbon material, first polymer material or metal material;
  • the material of the encapsulation layer includes a second polymer material
  • the temperature at which the encapsulation layer begins to soften is at least 10°C lower than the temperature at which the intermediate layer begins to soften.
  • the surrounding edges of the two surfaces of the intermediate layer are covered by an encapsulation layer, and the area of the encapsulation layer accounts for 30% to 100% of the area of the intermediate layer.
  • At least one surface of the intermediate layer is entirely covered by the encapsulation layer.
  • the carbon material comprises: at least one of carbon felt, carbon film, carbon black, acetylene black, fullerene, conductive graphite film or graphene film.
  • the first polymer material includes: polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyether ether Ketone, Polyimide, Polyamide, Polyethylene Glycol, Polyamideimide, Polycarbonate, Cyclic Polyolefin, Polyphenylene Sulfide, Polyvinyl Acetate, Polytetrafluoroethylene, Polymethylene Naphthalene , polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone , vinylon, polypropylene, acid anhydride modified polypropylene, polyethylene, ethylene and its copolymers, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polyester, polysulfone,
  • the metal material includes at least one of Ni, Ti, Ag, Au, Pt, Fe, Co, Cr, W, Mo, Pb, In, Zn or stainless steel.
  • the second polymer material includes: polypropylene, acid anhydride modified polypropylene, polyethylene, ethylene and its copolymers, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane , polyamide, polyester, amorphous ⁇ -olefin copolymer or at least one of the derivatives of the above substances.
  • a second aspect of the present invention provides an electrochemical device comprising at least one separator as described above, at least two electrode assemblies, an electrolyte, and an outer package, the electrode assemblies being in individually sealed chambers .
  • the outermost layer of the electrode assembly comprises a separator adjacent to the separator.
  • the outermost layer of at least one of the electrode assemblies comprises a separator, the separator is adjacent to the separator; the outermost layer of at least one of the electrode assemblies comprises a current collector, the The current collector is adjacent to the other side of the separator.
  • the separator has electron conductivity
  • the outermost layer of the electrode assembly includes a current collector
  • the current collector is adjacent to the separator
  • the separator is on both sides
  • the current collectors of the electrode assemblies have opposite polarities.
  • the separator is electrically insulating, and the outermost layer of the electrode assembly includes a current collector adjacent to the separator.
  • a third aspect of the present invention provides an electronic device comprising the electrochemical device of the second aspect.
  • the invention provides a separator for an electrochemical device, an electrochemical device and an electronic device.
  • the separator for an electrochemical device has ionic insulation and includes an intermediate layer and an encapsulation layer, and the encapsulation layer is located on the upper and lower surfaces of the intermediate layer;
  • the material of the layer includes at least one of carbon material, first polymer material or metal material;
  • the material of the encapsulation layer includes the second polymer material;
  • the temperature at which the encapsulation layer begins to soften is at least 10°C lower than the temperature at which the intermediate layer begins to soften.
  • FIG. 1 is a schematic cross-sectional view of a separator in an embodiment of the present invention.
  • Figure 2 is a schematic cross-sectional view of a separator in another embodiment of the present invention.
  • FIG. 3 is a schematic top view of a separator in an embodiment of the present invention.
  • FIG. 4 is a schematic cross-sectional view of the electrode assembly after encapsulation in an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of the electrochemical device of Comparative Example 3 of the present invention.
  • FIG. 7 is a schematic diagram of the electrochemical device of Comparative Example 4 of the present invention.
  • the present invention is explained by taking a lithium ion battery as an example of an electrochemical device, but the electrochemical device of the present invention is not limited to a lithium ion battery.
  • the present invention provides a separator for an electrochemical device, which has ionic insulation and includes an intermediate layer 2 and an encapsulation layer 1 , and the encapsulation layer 1 is located on the upper and lower surfaces of the intermediate layer 2 . superior;
  • the material of the intermediate layer 2 includes at least one of carbon material, first polymer material or metal material;
  • the material of the encapsulation layer 1 includes a second polymer material
  • the temperature at which the encapsulation layer 1 begins to soften (melting point or softening point) is at least 10°C lower than the temperature at which the intermediate layer begins to soften.
  • a separator for an electrochemical device the middle layer is a structural layer, and has high mechanical strength, high melting point or high softening point; Both the intermediate layer and the encapsulation layer have the advantages of good ionic insulation ability, certain thermal stability and thin thickness.
  • the temperature at which the encapsulation layer begins to soften is at least 10°C lower than the temperature at which the intermediate layer begins to soften, which can ensure the reliability of the encapsulation and the effectiveness of the ionic insulation.
  • the separator can be realized by hot pressing compounding of three layers of different films, or it can be realized by coating the encapsulation layer on both sides of the intermediate layer.
  • the surrounding edges of the two surfaces of the intermediate layer 2 are covered by the encapsulation layer 1 . That is, the main body surface portion of the intermediate layer 2 is not covered by the encapsulation layer.
  • Figure 3 is a schematic top view of such an embodiment.
  • the area of the encapsulation layer accounts for 30% to 100% of the area of the intermediate layer, and the absolute width of the encapsulation layer is greater than 2 mm.
  • the surrounding edges of the two surfaces of the intermediate layer are covered by the encapsulation layer, which reduces the coating amount and proportion of the encapsulation layer material as much as possible, reduces the proportion of ineffective substances, and can improve the energy density of the electrode assembly.
  • At least one surface of the intermediate layer is entirely covered by the encapsulation layer.
  • the carbon material includes at least one of carbon felt, carbon film, carbon black, acetylene black, fullerene, conductive graphite film or graphene film.
  • the first polymer material includes polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyether ether ketone , polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, Polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone, Vinylon, polypropylene, acid anhydride modified polypropylene, polyethylene, other ethylene and its copolymers (such as EVA, EEA, EAA, EVAL), polyvinyl chloride, polystyrene, other polyolefins, poly
  • the intermediate layer is made of polymer material. Since the density of the polymer material is lower than that of the commonly used metal-based current collector material, the weight of the inactive material can be reduced, thereby increasing the mass energy density of the electrode assembly.
  • the middle layer is made of polymer material. Compared with metal-based current collectors, the prepared separator has less probability of generating conductive debris under mechanical abuse (pinning, impact, extrusion, etc.) The wrapping is better, so it can improve the safety margin in the above-mentioned mechanical abuse situation and improve the safety test pass rate.
  • the metal material includes at least one of Ni, Ti, Ag, Au, Pt, Fe, Co, Cr, W, Mo, Pb, In, Zn or stainless steel, preferably includes At least one of Ni, Ti, Ag, Au, Pt, Fe or stainless steel.
  • the second polymer material includes polypropylene, acid anhydride modified polypropylene, polyethylene, other ethylene and its copolymers (eg EVA, EEA, EAA, EVAL), polyvinyl chloride , polystyrene, other polyolefins, polyether nitrile, polyurethane, polyamide, polyester, amorphous ⁇ -olefin copolymer or at least one of the derivatives of the above substances.
  • the thickness of the separator is 2 ⁇ m to 500 ⁇ m, preferably 5 ⁇ m to 50 ⁇ m, more preferably 5 ⁇ m to 20 ⁇ m.
  • the temperature at which the interlayer material begins to soften is greater than 130°C, preferably greater than 150°C.
  • the temperature at which the encapsulation layer material starts to soften is 120°C to 240°C, preferably 130°C to 170°C.
  • the materials of the intermediate layer and the encapsulation layer of the separator prepared by the present invention can be the same or different.
  • both are PP (polypropylene) , it is necessary to ensure that there is a difference of more than 20 °C in the temperature at which the intermediate layer and the encapsulation layer begin to soften.
  • the interfacial adhesion between the encapsulation layer and the intermediate layer is greater than 10 N/cm, preferably greater than 20 N/cm.
  • the interfacial adhesion between the encapsulation layer and the outer packaging is greater than 10 N/cm, preferably greater than 15 N/cm.
  • the ratio A of the cross-sectional area of the encapsulation layer in the inner unsealed glue area to the cross-sectional area of the encapsulation layer in the encapsulation area is 0 to 20, preferably 0.5 to 5, more preferably 0.5 to 2.
  • the position in the middle of the two tabs of the lithium ion battery is cut, the cross section is taken, and the SEM (scanning electron microscope) test is performed to calculate the area of the overflow area and the area of the encapsulation area in the SEM image.
  • FIG. 4 is a schematic cross-sectional view of the packaging area.
  • the middle of the aluminum-plastic film 3 is the packaging layer, and the left side is the packaging area 5.
  • the glue in the packaging area 5 is pressed by the upper and lower aluminum-plastic films 3 to the unsealed area to form the overflow area. 4.
  • the present invention also provides an electrochemical device comprising at least one separator of the present invention, at least two electrode assemblies, an electrolyte, and an outer package, the electrode assemblies being in individually sealed chambers.
  • the electrochemical device comprises at least one separator of the present invention
  • the separator is hermetically connected to the outer package of the electrochemical device, and two independent separators are formed on both sides of the separator. Sealed chambers, each sealed chamber has an electrode assembly and an electrolyte to form an independent electrochemical unit, wherein the separator has electron conductivity, and two sides of the separator can be respectively coated with opposite polarities. electrode active material. Adjacent electrochemical cells are connected in series through the electrodes comprising the separator of the present invention to form a bipolar lithium ion battery with a higher working voltage.
  • the separator has electron conductivity, and two adjacent electrode assemblies may each lead out a tab, and the polarities of the tabs of the two electrode assemblies are opposite, for example, when the separator
  • the side adjacent to electrode assembly A is coated with positive active material and the side adjacent to electrode assembly B is coated with negative active material
  • electrode assembly A leads out the negative electrode tab
  • electrode assembly B leads out the positive electrode tab.
  • the output voltage between the two tabs is the sum of the output voltages of the two electrochemical cells.
  • the separator has electronic insulation, two adjacent electrode assemblies can each lead out two tabs, and the positive tab of electrode assembly A is connected in series with the negative tab of electrode assembly B Together, the negative tab of the electrode assembly A and the positive tab of the electrode assembly B are output tabs, and the output voltage is the sum of the output voltages of the two electrochemical cells.
  • the separator has electronic conductivity, and a tab can be drawn out from the separator for monitoring the working state of the lithium ion battery.
  • the outermost layer of the electrode assembly comprises a separator adjacent to the separator.
  • the outermost layer of the electrode assembly may contain at least one of a separator or a current collector according to winding or other endings, for example, only a separator, only a current collector, or a part of a separator and another part of a separator.
  • a current collector is included; wherein, the current collector may be in at least one state of the outermost layer being uncoated with active material, partially coated with active material, or fully coated with active material.
  • the electrochemical device of the present invention comprises at least one separator, which may be electronically insulating or electronically conductive, the separator is hermetically connected to the outer package, and Separate sealed chambers are formed on both sides of the separator, each sealed chamber contains an electrode assembly and an electrolyte to form an electrochemical unit, wherein the two sides of the separator are in direct contact with the separators of the adjacent electrode assemblies and form electrical insulation. At this time, two tabs are drawn from each of the two electrode assemblies, and the two electrode assemblies are connected in series through the tabs.
  • the outermost layer of at least one of the electrode assemblies comprises a separator, the separator is adjacent to the separator; the outermost layer of at least one of the electrode assemblies comprises a current collector, the The current collector is adjacent to the other side of the separator.
  • the electrochemical device of the present invention comprises at least one separator, the separator is hermetically connected to the outer package, and independent sealed chambers are formed on both sides of the separator, each sealed chamber It contains an electrode assembly and an electrolyte to form an electrochemical unit, wherein the separator has electron conductivity, one side of the separator can be coated with electrode active material, and the other side is in contact with the separator of the electrode assembly to form Electrical insulation.
  • the side of the separator close to the electrode assembly A is coated with positive active material, and the side close to the electrode assembly B is in contact with the separator of the electrode assembly B to form electrical insulation with the electrode assembly B.
  • two tabs are drawn from each of the two electrode assemblies, and one tab is drawn from the separator, which is connected in parallel with the positive tab of electrode assembly A, and then connected in series with the negative tab of electrode assembly B.
  • the electrochemical device of the present invention comprises at least one separator, the separator is hermetically connected to the outer package, and independently sealed chambers are formed on both sides of the separator, each sealed chamber It contains an electrode assembly and an electrolyte to form an electrochemical unit, the separator has electronic insulation, one side of the separator is in contact with the separator of the electrode assembly to form electrical insulation, and the other side of the separator is directly connected to the separator. Current collector contacts of the electrode assembly. At this time, two tabs are drawn from each of the two electrode assemblies, and the two electrode assemblies are connected in series through the tabs.
  • the separator has electron conductivity
  • the outermost layer of the electrode assembly includes a current collector
  • the current collector is adjacent to the separator
  • the separator is on both sides
  • the current collectors of the electrode assemblies have opposite polarities.
  • the electrochemical device of the present invention comprises at least one separator, the separator has electron conductivity, the separator is sealed with the outer package, and the separators are formed on both sides of the separator independently. Sealed chambers, each sealed chamber contains an electrode assembly and an electrolyte to form an electrochemical unit, wherein one side of the separator is coated with electrode active material, and the other side is directly in contact with the current collector of the electrode assembly and electrically connected.
  • the side of the separator close to the electrode assembly A is coated with the positive active material, and the side close to the electrode assembly B is in direct contact with and electrically connected to the negative electrode current collector of the electrode assembly B.
  • electrode assembly A can lead out a negative electrode tab
  • electrode assembly B can lead out a positive electrode tab
  • the two electrochemical cells are connected in series through the separator; or electrode assemblies A and B each lead out two tabs, the electrode The positive electrode tabs of the assembly A are connected in series with the negative electrode tabs of the electrode assembly B.
  • the separator can lead out a tab for monitoring the working status of the battery.
  • the separator is electrically insulating, and the outermost layer of the electrode assembly includes a current collector adjacent to the separator.
  • the electrochemical device of the present invention comprises at least one separator, the separator is hermetically connected to the outer package, and independent sealed chambers are formed on both sides of the separator, each sealed chamber It contains an electrode assembly and an electrolyte to form an electrochemical unit, wherein the separator is an electronic insulator, and the two sides of the separator are directly connected with the outermost current collectors of the adjacent electrode assemblies to form electrical insulation. At this time, two tabs are drawn from each of the two electrode assemblies, and the two electrode assemblies are connected in series through the tabs.
  • the separator has electron conductivity
  • a primer layer may be included between the separator and the electrode active material, and the function of the primer layer is to improve the adhesion between the separator and the active material.
  • the bonding performance can be improved, and the electronic conduction ability between the separator and the active material can be improved.
  • the primer layer is usually obtained by coating the slurry formed by mixing conductive carbon black, styrene-butadiene rubber and deionized water on the separator, and drying, and the primer layer on both sides of the separator can be the same. , can also be different.
  • the present invention also provides an electronic device comprising the electrochemical device of any one of the above.
  • the electrode assembly of the present invention is not particularly limited, and any electrode assembly in the prior art can be used as long as the object of the present invention can be achieved, for example, a laminated electrode assembly or a wound electrode assembly can be used.
  • the electrode assembly generally includes a positive pole piece, a negative pole piece and a separator.
  • a negative electrode sheet typically includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode current collector is not particularly limited, and any negative electrode current collector known in the art can be used, such as copper foil, aluminum foil, aluminum alloy foil, and composite current collector.
  • the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material is not particularly limited, and any negative electrode active material known in the art may be used.
  • at least one of artificial graphite, natural graphite, mesocarbon microspheres, soft carbon, hard carbon, silicon, silicon carbon, lithium titanate, and the like may be included.
  • the positive electrode sheet in the present invention is not particularly limited as long as the object of the present invention can be achieved.
  • the positive electrode sheet typically includes a positive electrode current collector and a positive electrode active material.
  • the positive electrode current collector is not particularly limited, and can be any positive electrode current collector known in the art, such as aluminum foil, aluminum alloy foil, or composite current collector.
  • the positive active material is not particularly limited, and can be any positive active material in the prior art, and the active material includes NCM811, NCM622, NCM523, NCM111, NCA, lithium iron phosphate, lithium cobaltate, lithium manganate, and iron manganese phosphate At least one of lithium or lithium titanate.
  • the electrolyte in the present invention is not particularly limited, any electrolyte known in the art can be used, for example, it can be any one of gel state, solid state and liquid state, for example, the liquid electrolyte solution can include lithium salt and non-aqueous solvent.
  • the lithium salt is not particularly limited, and any lithium salt known in the art can be used as long as the object of the present invention can be achieved.
  • the lithium salt may include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bistrifluoromethanesulfonimide LiN(CF 3 SO 2 ) 2 ( LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 ) (LiFSI), lithium bis-oxalate borate LiB(C 2 O 4 ) 2 (LiBOB) or lithium difluorooxalate borate LiBF 2 ( At least one of C 2 O 4 ) (LiDFOB).
  • LiPF 6 can be selected as the lithium salt.
  • the non-aqueous solvent is not particularly limited as long as the object of the present invention can be achieved.
  • the non-aqueous solvent may include at least one of carbonate compounds, carboxylate compounds, ether compounds, nitrile compounds, or other organic solvents.
  • the carbonate compound may include diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethylene propylene carbonate Ester (EPC), Methyl Ethyl Carbonate (MEC), Ethylene Carbonate (EC), Propylene Carbonate (PC), Butylene Carbonate (BC), Vinyl Ethylene Carbonate (VEC), Fluorocarbonate Ethyl carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, 1,1,2,2-carbonate Tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1-fluorocarbonate , At least one of 1,2-trifluoro-2-methylethylene or trifluoromethylethylene carbonate,
  • the separator in the present invention is not particularly limited, and for example, the separator includes a polymer, an inorganic substance, or the like formed of a material that is stable to the electrolyte solution of the present invention.
  • the separator should generally be ionically conductive and electronically insulating.
  • the separator may include a substrate layer and a surface treatment layer.
  • the substrate layer can be a non-woven fabric, film or composite film with a porous structure, and the material of the substrate layer can be selected from at least one of polyethylene, polypropylene, polyethylene terephthalate and polyimide. kind.
  • polypropylene porous membranes, polyethylene porous membranes, polypropylene non-woven fabrics, polyethylene non-woven fabrics, or polypropylene-polyethylene-polypropylene porous composite membranes may be used.
  • at least one surface of the substrate layer is provided with a surface treatment layer, and the surface treatment layer can be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic substance.
  • the inorganic layer includes inorganic particles and a binder
  • the inorganic particles are not particularly limited, and can be selected from aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, for example , at least one of zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate.
  • the binder is not particularly limited, for example, it can be selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyethylene One or a combination of rolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the material of the polymer includes polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly( At least one of vinylidene fluoride-hexafluoropropylene).
  • the present invention also provides a method for preparing a separator, which can be used to prepare a separator in which all the above-mentioned encapsulation layers are coated with an intermediate layer, comprising the following steps:
  • the present invention also provides a method for preparing a separator, which can be used to prepare a separator in which all the above-mentioned encapsulation layers are coated with an intermediate layer, comprising the following steps:
  • the present invention also provides a method for preparing a separator, which can be used to prepare a separator coated with an intermediate layer around the above-mentioned encapsulation layer, comprising the following steps:
  • the encapsulation layers are prepared on both sides of the intermediate layer respectively;
  • the present invention also provides a method for preparing a separator, which can be used to prepare a separator coated with an intermediate layer around the above-mentioned encapsulation layer, comprising the following steps:
  • the dispersant is not particularly limited in the present invention, and can be a polar organic solvent commonly used in the art, such as NMP (N-methylpyrrolidone), DMF (N,N-dimethylformamide), THF (tetrahydrofuran) )Wait.
  • NMP N-methylpyrrolidone
  • DMF N,N-dimethylformamide
  • THF tetrahydrofuran
  • the negative electrode active material graphite, conductive carbon black, and styrene-butadiene rubber were mixed according to a mass ratio of 96:1.5:2.5, deionized water was added as a solvent, and a slurry with a solid content of 70% was prepared and stirred evenly.
  • the slurry was uniformly coated on one surface of a copper foil with a thickness of 10 ⁇ m, and dried at 110° C. to obtain a negative electrode pole piece with a single-sided coating of a negative electrode active material layer with a coating thickness of 150 ⁇ m.
  • the above coating steps were repeated on the other surface of the negative pole piece. After the coating is completed, the pole piece is cut into a size of 41mm ⁇ 61mm and the tabs are welded for later use.
  • the positive active material LiCoO 2 , conductive carbon black, and PVDF (polyvinylidene fluoride) were mixed in a mass ratio of 97.5:1.0:1.5, and NMP was added as a solvent to prepare a slurry with a solid content of 75%, which was stirred evenly.
  • the slurry was uniformly coated on one surface of an aluminum foil with a thickness of 12 ⁇ m, and dried at 90° C. to obtain a single-sided positive electrode sheet with a coating thickness of 100 ⁇ m coated with a positive electrode active material layer.
  • the above steps are then repeated on the other surface of the positive pole piece. After the coating is completed, the pole piece is cut into a size of 38mm ⁇ 58mm and the tabs are welded for use.
  • organic solvents EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • LiPF 6 lithium hexafluorophosphate
  • a PE (polyethylene) film with a thickness of 15 ⁇ m was selected as the separator, a positive electrode piece of Preparation Example 2 was placed on both sides of the negative electrode piece of Preparation Example 1, and a layer of separator film was placed between the positive electrode piece and the negative electrode piece, A lamination is formed, and then the four corners of the entire lamination structure are fixed, and the positive electrode tab and the negative electrode tab are drawn out to obtain the electrode assembly A.
  • a PE film with a thickness of 15 ⁇ m is used as the separator, a negative electrode is placed on both sides of the positive electrode, and a separator is placed between the positive electrode and the negative electrode to form a stack, and then the four The angle is fixed, and the positive electrode tab and the negative electrode tab are drawn out to obtain the electrode assembly B.
  • an encapsulation layer PP with a thickness of 40 ⁇ m on the surrounding edges of the two surfaces of the intermediate layer PET (polyethylene terephthalate) film with a thickness of 20 ⁇ m, and the width of the encapsulation layer PP is 5 mm , the temperature at which the intermediate layer PET begins to soften is 270°C, the temperature at which the encapsulation layer PP begins to soften is 150°C, and the compression ratio of the thickness of the encapsulation layer is 70%.
  • the intermediate layer PET polyethylene terephthalate
  • the compressibility of the thickness of the packaging layer in each embodiment is adjusted, as shown in Table 1 for details.
  • the above-mentioned assembled semi-finished product is placed in another assembly fixture, the electrode assembly B of Preparation Example 4 is placed on the separator, the other side of the separator is in contact with the separator of the electrode assembly B, and then another thickness of the punched hole is formed.
  • the 90 ⁇ m aluminum-plastic film pits are covered with the electrode assembly B facing down, and then the two aluminum-plastic films and the separator are heat-sealed together by hot pressing, so that the electrode assembly A and the electrode assembly B are separated by the separator.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • the electrolyte of Preparation Example 3 was respectively injected into the two cavities of the above-mentioned assembled electrode assembly and packaged, the tabs of the two electrode assemblies were drawn out of the outer packaging, and the positive tab of the electrode assembly A was welded to the negative tab of the electrode assembly B. Together, the series conduction between the two electrode assemblies is achieved.
  • the thickness is 20%, the rest is the same as that in Example 1.
  • PP is used for the encapsulation layer material
  • PP is used for the intermediate layer material
  • the temperature at which the encapsulation layer begins to soften is 130°C
  • the temperature at which the intermediate layer begins to soften is 150°C
  • the compressibility of the thickness of the encapsulation layer is 40%. The rest are the same as in Example 1.
  • the procedure is the same as Example 1, except that PI (polyimide) is used as the material of the intermediate layer in the preparation of the separator, the temperature at which the intermediate layer begins to soften is 334° C., and the compressibility of the thickness of the encapsulation layer is 40%.
  • PI polyimide
  • the encapsulation layer material uses PS (polystyrene), the intermediate layer material uses stainless steel, the encapsulation layer begins to soften at 240°C, the intermediate layer begins to soften at 1440°C, and the encapsulation layer thickness compressibility Except that it is 40%, the rest is the same as Example 1.
  • PS polystyrene
  • the intermediate layer material uses stainless steel
  • the encapsulation layer begins to soften at 240°C
  • the intermediate layer begins to soften at 1440°C
  • the encapsulation layer thickness compressibility Except that it is 40%, the rest is the same as Example 1.
  • the temperature at which the intermediate layer began to soften was 334°C
  • the compression ratio of the thickness of the encapsulation layer was 40%
  • the interface adhesion between the encapsulation layer and the intermediate layer was 28N/m.
  • the interface adhesion between the layer and the outer package was the same as that of Example 1 except that it was 17.3 N/m.
  • PS is used for the encapsulation layer material
  • PI is used for the intermediate layer material
  • the temperature at which the encapsulation layer begins to soften is 240°C
  • the temperature at which the intermediate layer material begins to soften is 334°C
  • the compressibility of the encapsulation layer thickness is 40%.
  • the intermediate layer material In the preparation process of the separator, PI is used as the intermediate layer material, the temperature at which the intermediate layer material starts to soften is 334° C., and the ratio A is 0.1, the rest is the same as that of Example 1.
  • PI was used as the intermediate layer material
  • the temperature at which the intermediate layer material began to soften was 334°C
  • the compressibility of the encapsulation layer thickness was 20%
  • the ratio A was 20, the rest was the same as Example 1.
  • the size of the ratio A is adjusted by adjusting the gluing width of the encapsulation gluing area. The smaller the gluing width, the smaller the A value.
  • Example 1 In the preparation process of the separator, Al was used for the intermediate layer material, the temperature at which the encapsulation layer material began to soften was 130°C, the temperature at which the intermediate layer material began to soften was 660°C, and the compressibility of the encapsulation layer thickness was 40%.
  • Example 1 is the same.
  • the intermediate layer material is used as the intermediate layer material, the temperature at which the intermediate layer material starts to soften is 334°C, the compression ratio of the encapsulation layer thickness is 40%, and the intermediate layer thickness is 1000 ⁇ m, the rest is the same as Example 1.
  • PI was used as the intermediate layer material
  • the temperature at which the intermediate layer material began to soften was 334°C
  • the compressibility of the encapsulation layer thickness was 40%
  • the intermediate layer thickness was 10 ⁇ m, the rest was the same as Example 1.
  • the intermediate layer material is used as the intermediate layer material, the temperature at which the intermediate layer material begins to soften is 334°C, the compressibility of the encapsulation layer thickness is 40%, and the intermediate layer thickness is 2 ⁇ m, the rest is the same as Example 1.
  • PI is used for the intermediate layer material, the temperature at which the intermediate layer material starts to soften is 334°C, and the compression ratio of the thickness of the encapsulation layer is 40%;
  • the above assembled semi-finished product is placed in another assembly fixture, the electrode assembly B of Preparation Example 4 is placed on the separator, the other side of the separator is in contact with the current collector of the electrode assembly B, and then another thickness of the punched hole is formed.
  • a 90 ⁇ m aluminum-plastic film pit is covered on the electrode assembly B, and then the two aluminum-plastic films and the separator are heat-sealed together by hot pressing, so that the electrode assembly A and the electrode assembly B are separated by the separator.
  • An assembled electrode assembly is obtained.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • the material of the intermediate layer is stainless steel, the melting point of the intermediate layer is 1440°C, and the compression ratio of the thickness of the encapsulation layer is 40%;
  • the above-mentioned assembled semi-finished product is placed in the assembly fixture, the separator is facing up, the electrode assembly B of Preparation Example 4 is placed on the separator with the negative electrode facing down, and the other side of the separator is in contact with the negative electrode current collector of the electrode assembly B, and then the Another aluminum-plastic film with a thickness of 90 ⁇ m formed by punching is covered on the electrode assembly B with the pit face down, and then the two aluminum-plastic films and the separator are heat-sealed together by hot pressing to make the electrode assembly A and the electrode assembly.
  • Assembly B was separated by a separator, resulting in an assembled electrode assembly.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • Electrode assembly liquid injection packaging
  • the electrolyte of Preparation Example 3 was respectively injected into the two cavities of the assembled electrode assembly and then packaged.
  • the tabs of the electrode assemblies A and B were both drawn out of the outer packaging, and the two electrochemical cells were connected in series through the separator to obtain a lithium ion battery. .
  • the material of the intermediate layer is PI
  • the temperature at which the material of the intermediate layer begins to soften is 334°C
  • the compression ratio of the thickness of the encapsulation layer is 40%
  • the punched packaging film (aluminum-plastic film) with a thickness of 90 ⁇ m in the assembly jig with the pit face up, then place the electrode assembly A of Preparation Example 4 in the pit, and then place the separator in the electrode assembly A.
  • the side of the separator On the upper side of the separator, the side of the separator is in contact with the current collector of the electrode assembly A, and an external force is applied to press it.
  • the above assembled semi-finished product is placed in another assembly fixture, the electrode assembly B of Preparation Example 4 is placed on the separator, the other side of the separator is in contact with the current collector of the electrode assembly B, and then another thickness of the punched hole is formed.
  • a 90 ⁇ m aluminum-plastic film pit is covered on the electrode assembly B, and then the two aluminum-plastic films and the separator are heat-sealed together by hot pressing, so that the electrode assembly A and the electrode assembly B are separated by the separator.
  • An assembled electrode assembly is obtained.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • the material of the intermediate layer is PI
  • the temperature at which the material of the intermediate layer begins to soften is 334°C
  • the compression ratio of the thickness of the encapsulation layer is 40%
  • both sides of the intermediate layer are coated with PP.
  • the preparation steps of the separator are:
  • the material of the intermediate layer is PI
  • the temperature at which the material of the intermediate layer begins to soften is 334°C
  • the compression ratio of the thickness of the encapsulation layer is 40%
  • both sides of the intermediate layer are coated with PP.
  • the preparation steps of the separator are:
  • the above assembled semi-finished product is placed in another assembly fixture, the electrode assembly B of Preparation Example 4 is placed on the separator, the other side of the separator is in contact with the current collector of the electrode assembly B, and then another thickness of the punched hole is formed.
  • a 90 ⁇ m aluminum-plastic film pit is covered on the electrode assembly B, and then the two aluminum-plastic films and the separator are heat-sealed together by hot pressing, so that the electrode assembly A and the electrode assembly B are separated by the separator.
  • An assembled electrode assembly is obtained.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • the material of the intermediate layer is PI
  • the temperature at which the material of the intermediate layer begins to soften is 334°C
  • the compression ratio of the thickness of the encapsulation layer is 40%
  • both sides of the intermediate layer are coated with PP.
  • the preparation steps of the separator are:
  • the punched packaging film (aluminum-plastic film) with a thickness of 90 ⁇ m in the assembly jig with the pit face up, then place the electrode assembly A of Preparation Example 4 in the pit, and then place the separator in the electrode assembly A.
  • the side of the separator On the upper side of the separator, the side of the separator is in contact with the current collector of the electrode assembly A, and an external force is applied to press it.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • the intermediate layer is stainless steel, the melting point is 1440°C, and the compressibility of the thickness of the encapsulation layer is 40%.
  • the above-mentioned assembled semi-finished product is placed in another assembly fixture, the electrode assembly B of Preparation Example 4 is placed on the separator, and the other side of the separator is in contact with the positive current collector of the electrode assembly B, and then the other side of the punched shape is placed.
  • the aluminum-plastic film with a thickness of 90 ⁇ m is covered on the electrode assembly B with the pit face down, and then the two aluminum-plastic films and the separator are heat-sealed together by hot pressing, so that the electrode assembly A and the electrode assembly B are separated by the separator. , to obtain the assembled electrode assembly.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • Electrode assembly liquid injection packaging
  • the electrolyte of Preparation Example 3 was respectively injected into the two cavities of the assembled electrode assembly and then packaged, the tabs of the two electrode assemblies were drawn out of the outer packaging, and the positive tab of the electrode assembly A and the negative tab of the electrode assembly B were welded to each other. Together, the series conduction between the two electrode assemblies is achieved.
  • the tab of the separator is connected in parallel with the positive tab of the electrode assembly A, and then connected in series with the negative tab of the electrode assembly B to obtain a lithium ion battery.
  • the compression ratio of the thickness of the encapsulation layer is 40%
  • the double-sided coated negative pole piece, the first separator, the double-sided coated positive pole piece, and the second separator are stacked and arranged in sequence to form a stack, and then the entire stack is wound, and the positive electrode tab and the negative electrode tab are drawn out.
  • a diaphragm is placed on the outermost side.
  • a polyethylene (PE) film with a thickness of 15 ⁇ m was selected as the separator, the negative pole piece was prepared by Preparation Example 1, and the positive pole piece was prepared by Preparation Example 2.
  • Electrode assembly A was prepared.
  • the double-sided coated negative pole piece, the first separator, the double-sided coated positive pole piece, and the second separator are stacked in sequence to form a stack, and then the entire stack is wound to lead out the positive electrode tab and the negative electrode tab, and the second
  • the separator is placed on the outermost side, the negative pole piece is prepared by Preparation Example 1, and the positive pole piece is prepared by Preparation Example 2.
  • the separator is a polyethylene (PE) film with a thickness of 15 ⁇ m. Electrode assembly B was prepared.
  • the material of the intermediate layer is stainless steel, the melting point is 1440°C, and the compression ratio of the thickness of the encapsulation layer is 40%;
  • the double-sided coated negative pole piece, the first separator, the double-sided coated positive pole piece, and the second separator are stacked and arranged in sequence to form a stack, and then the entire stack is wound, and the positive electrode tab and the negative electrode tab are drawn out.
  • a diaphragm is placed on the outermost side.
  • a polyethylene (PE) film with a thickness of 15 ⁇ m was selected as the separator, the negative pole piece was prepared by Preparation Example 1, and the positive pole piece was prepared by Preparation Example 2.
  • Electrode assembly A was prepared.
  • the double-sided coated negative pole piece, the first separator, the double-sided coated positive pole piece, and the second separator are stacked in sequence to form a stack, and then the entire stack is wound to lead out the positive electrode tab and the negative electrode tab, and the positive electrode
  • the positive current collector of the sheet is placed on the outermost side.
  • a polyethylene (PE) film with a thickness of 15 ⁇ m was selected as the separator
  • the negative pole piece was prepared by Preparation Example 1
  • the positive pole piece was prepared by Preparation Example 2.
  • Electrode assembly B was prepared.
  • the punched packaging film (aluminum-plastic film) with a thickness of 90 ⁇ m in the assembly jig with the pit facing up, then place the above-mentioned electrode assembly A in the pit, and then place the separator on the electrode assembly A.
  • One side of the plate is in contact with the first diaphragm of the electrode assembly A, and is pressed by an external force.
  • the above-mentioned assembled semi-finished product is placed in another assembly fixture, the above-mentioned electrode assembly B is placed on the separator, the other side of the separator is in contact with the positive current collector of the electrode assembly B, and then the other thickness of the punched hole is 90 ⁇ m.
  • the aluminum-plastic film pits face down and cover the electrode assembly B, and then the two aluminum-plastic films and the separator are heat-sealed together by hot pressing, so that the electrode assembly A and the electrode assembly B are separated by the separator.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • Electrode assembly liquid injection packaging
  • the electrolyte of Preparation Example 3 was respectively injected into the two cavities of the assembled electrode assembly and then packaged, the tabs of the two electrode assemblies were drawn out of the outer packaging, and the positive tab of the electrode assembly A and the negative tab of the electrode assembly B were welded to each other. Together, the series conduction between the two electrode assemblies is achieved.
  • the material of the intermediate layer is stainless steel, the melting point is 1440°C, and the compression ratio of the thickness of the encapsulation layer is 40%;
  • the double-sided coated negative pole piece, the separator, and the double-sided coated positive pole piece are stacked in sequence to form a stack, and then the entire stack is wound to lead out the positive electrode tab and the negative electrode tab, and the negative electrode collector of the negative electrode tab. placed on the outermost side.
  • a polyethylene (PE) film with a thickness of 15 ⁇ m was selected as the separator
  • the negative pole piece was prepared by Preparation Example 1
  • the positive pole piece was prepared by Preparation Example 2.
  • Electrode assembly A was prepared.
  • the double-sided coated negative pole piece, the separator, and the double-sided coated positive pole piece are stacked in sequence to form a stack, and then the whole stack is wound to lead out the positive electrode tab and the negative electrode tab, and the positive electrode collector of the positive electrode is placed. on the outermost side.
  • a polyethylene (PE) film with a thickness of 15 ⁇ m was selected as the separator, the negative pole piece was prepared by Preparation Example 1, and the positive pole piece was prepared by Preparation Example 2.
  • Electrode assembly B was prepared.
  • the punched packaging film (aluminum-plastic film) with a thickness of 90 ⁇ m in the assembly jig with the pit face up, and then place the above-mentioned electrode assembly A in the pit, so that the positive pole piece of the electrode assembly A faces up, and place it.
  • the separator is placed on the electrode assembly A, and one side of the separator is in contact with the negative electrode current collector of the electrode assembly A, and is pressed by an external force.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • Electrode assembly liquid injection packaging
  • the electrolyte of Preparation Example 3 was respectively injected into the two cavities of the assembled electrode assembly and then packaged.
  • the tabs of the electrode assemblies A and B were both drawn out of the outer packaging, and the two electrochemical cells were connected in series through the separator to obtain a lithium ion battery. .
  • the positive pole piece of Preparation Example 2 and the negative pole piece of Preparation Example 1 were stacked together, with a PE separator with a thickness of 15 ⁇ m between the positive pole piece and the negative pole piece, packaged with aluminum foil, and encapsulated and injected into the electrolyte of Preparation Example 3. , the tabs of the positive and negative pole pieces lead out of the outer packaging. Get a lithium-ion battery.
  • Electrode assembly liquid injection packaging
  • the four corners of the electrode assemblies A and B of Preparation Example 4 were fixed, packaged with an aluminum-plastic film, and then sealed around the package; the electrolyte of Preparation Example 3 was injected into the aluminum-plastic film respectively, and all the electrode assemblies A and B were sealed.
  • the tabs are drawn out of the aluminum-plastic film.
  • the positive electrode tab of electrode assembly A and the negative electrode tab of electrode assembly B are welded and connected together by laser welding to realize series conduction between electrode assemblies A and B, and the battery assembly is completed.
  • Electrode assembly assembly and liquid injection packaging are Electrode assembly assembly and liquid injection packaging:
  • the positive electrode tab of the electrode assembly of Preparation Example 4 was coated with sealant, and the negative electrode of the electrode assembly A was welded to the positive electrode tab of the electrode assembly B, so that the electrodes of the electrode assembly A and the electrode assembly B were connected in series, and the connected electrode assembly was sealed and molded in the aluminum plastic film.
  • sealing and encapsulation are carried out along the positive electrode sealant between each electrode assembly in the width direction of the electrode assembly to realize the isolation of the cavity between each electrode assembly. Inject them into the cavity where the two electrode assemblies are located.
  • the positive electrode tab is drawn from one side in the length direction of the electrode assembly, the negative electrode tab is drawn from one side, and the remaining series-connected tabs are all located in the outer package of the electrode assembly.
  • Electrode assembly A of Preparation Example 4 into one side of the formed aluminum-plastic film, cover the upper layer of aluminum-plastic film, and press the side with the electrode assembly A; Cover with glue and press the upper and lower layers of aluminum-plastic films tightly, apply it from the tail of the electrode assembly to the top packaging area along the length of the electrode assembly, and solidify and form.
  • the electrode assembly B of Preparation Example 4 was placed in the side vacant area of the electrode assembly A, and the entire aluminum-plastic film was top-sealed.
  • the top encapsulation intersects the glue-coated area perpendicularly, and is contact-sealed so that the electrode assemblies A and B are in independently sealed cavities, respectively.
  • the packaging film formed by punching the packaging film is an aluminum-plastic film with a thickness of 90 ⁇ m, placed in an assembly jig with the pit surface facing up, and then the electrode assembly A of Preparation Example 4 was placed in the pit, and the electrode assembly of Preparation Example 4 was placed.
  • B is placed on the electrode assembly A, and the electrode assembly A and the electrode assembly B are separated by a diaphragm and pressed tightly. Then, cover the electrode assembly B with another piece of packaging film with the pit face down, and heat seal around it.
  • Electrode assembly liquid injection packaging
  • the electrolyte of Preparation Example 3 was injected into the cavity where the two electrode assemblies were located. After the injection, the surrounding areas were encapsulated. The positive and negative electrodes of the electrode assemblies were both led out of the outer packaging, and the tabs were dislocated to avoid sealing failure caused by stacking of the tabs in the thickness direction.
  • the positive electrode tab of the electrode assembly A and the negative electrode tab of the electrode assembly B are welded together to realize series conduction between the two electrode assemblies.
  • the separator uses a common single-layer PP separator directly as the separator, with a thickness of 20 ⁇ m and a softening temperature of 165 °C;
  • the above assembled semi-finished product was placed in another assembly fixture, and the electrode assembly B of Preparation Example 4 was placed on the PP separator, and then another punched aluminum-plastic film with a thickness of 90 ⁇ m was placed face down to cover the electrode assembly.
  • the two aluminum-plastic films are heat-sealed together with the PP separator by means of hot pressing, so that the electrode assembly A and the electrode assembly B are separated by the PP separator to obtain an assembled electrode assembly.
  • the assembled electrode assembly has two independent cavities, wherein the electrode assembly A corresponds to the first cavity, and the electrode assembly B corresponds to the second cavity.
  • the electrolyte solution of Preparation Example 3 was injected into the cavity where the two electrode assemblies were located, and after the liquid injection, packaging was carried out around them. Welded together to achieve series conduction between the two electrode assemblies.
  • the separator thickness is 20 ⁇ m, and the softening temperature is 165 °C, the rest is the same as that of Comparative Example 6.
  • the thickness of the separator is 20 ⁇ m, and the melting point is 1440 °C, the rest is the same as that of Comparative Example 6.
  • sample 1 is cut into a test strip with a width of 8mm and a length of 6cm, to ensure that in this area, the encapsulation layer completely covers the intermediate layer to obtain sample 2;
  • sample 1 Cut sample 1 into a test strip with a width of 8 mm and a length of 6 cm to ensure that in this area, the encapsulation layer completely covers the outer packaging, and sample 2 is obtained;
  • sample 1 Cut sample 1 into a test strip with a width of 8 mm, to ensure that the test strip completely preserves the entire sealing area, and the outer packaging on both sides of the sealing area is also intact to obtain sample 2;
  • the lithium-ion battery was allowed to stand at room temperature for 30 minutes, charged with a constant current at a charging rate of 0.05C to a voltage of 4.45V (rated voltage of Comparative Example 1) or 8.90V (rated voltage of other comparative examples and all examples), and then charged at 0.05 C rate
  • the electrochemical device was discharged to 3.00V (Comparative Example 1 rated voltage) or 6.00V (other Comparative Examples and all Examples), and the above charging/discharging steps were repeated for 3 cycles to complete the formation of the electrochemical device to be tested.
  • the electrochemical device was charged with a constant current at a charging rate of 0.1C to a voltage of 4.45V (rated voltage of Comparative Example 1) or 8.90V (other comparative examples and all Examples), and then the electrochemical device was charged at a discharge rate of 0.1C
  • the device was discharged to 3.00V (rated voltage of comparative example 1) or 6.00V (other comparative examples and all examples), recorded its discharge capacity, and then calculated its energy density at 0.1C discharge:
  • the test temperature is 25°C, charge at 0.5C constant current to 4.45V (rated voltage of Comparative Example 1) or 8.90V (other comparative examples and all examples), charge at constant voltage to 0.025C, and let stand for 5 minutes at 0.5C Discharge to 3.00V (rated voltage of comparative example 1) or 6.00V (other comparative examples and all examples), the capacity obtained in this step is the initial capacity, and after 50 cycles of 0.5C charge/0.5C discharge cycle test, calculate The ratio of the capacity of a lithium-ion battery to its initial capacity.
  • the test temperature is 25°C, and the constant current is charged at 3C to 4.45V (rated voltage of Comparative Example 1) or 8.90V (other comparative examples and all the examples), and the constant voltage is charged to 0.025C.
  • a thermocouple is placed in the center just above the cell to test the temperature change during the charging process in real time, and record the above-mentioned maximum temperature minus the test temperature of 25°C, which is the 3C charging temperature rise.
  • the lithium-ion battery to be tested was charged to a voltage of 4.45V (the rated voltage of Comparative Example 1) or 8.90V (the other comparative examples and all the examples) at a rate of 0.05C, and then charged to a current of 0.025C ( cut-off current), make the battery fully charged, and record the appearance of the battery before the test.
  • the battery was subjected to a piercing test in an environment of 25 ⁇ 3°C.
  • the diameter of the steel nail was 4mm and the piercing speed was 30mm/s.
  • the piercing positions were located 15mm away from the edge of the Al tab electrode assembly and 15mm away from the edge of the Ni tab electrode assembly.
  • the test is stopped after 3.5min or the surface temperature of the electrode assembly drops to 50°C. Take 10 electrode assemblies as a group, observe the battery state during the test, and take the battery not burning and not exploding as the judgment standard, and 10 times the nail penetration test is passed. 9 times or more is judged to pass the nail penetration
  • Lithium-ion batteries with external series structure of two independent electrode assemblies lithium-ion batteries with two independent electrode assemblies in series with head-to-tail structure, and lithium-ion batteries with two independent electrode assemblies side by side in series structure have higher energy density (NG means not measured).
  • the drop damage ratios of Examples 1-5, 7, 11-12, 15-18, 20-23, and 25 of the present invention are reduced, indicating that compared with the existing The lithium ion battery with the two independent electrode assemblies in series with the head and the tail, and the lithium ion battery with the two independent electrode assemblies side by side in series have a lower drop damage ratio; compared with Comparative Examples 8-9, the drop damage ratio of the embodiment of the present invention is significantly reduced , indicating that the separator prepared by the present invention can be very well resistant to drop damage when applied to a lithium ion battery.
  • the ratio of the discharge capacity after 50 cycles to the first discharge capacity of the embodiment of the present invention does not substantially change.
  • the separator prepared by the present invention can improve the packaging reliability of the lithium ion battery when applied to the lithium ion battery, and achieves good technical effects.

Abstract

一种电化学装置用隔板、电化学装置及电子装置,电化学装置用隔板具有离子绝缘性,包括中间层和封装层,封装层位于中间层的上下两个表面上;中间层的材料包括碳材料、第一高分子材料或金属材料中的至少一种;封装层的材料包括第二高分子材料;封装层开始软化的温度比中间层开始软化的温度至少低10℃。通过三层复合膜叠加,可以保证离子绝缘和封装的可靠性。

Description

一种电化学装置用隔板、电化学装置及电子装置 技术领域
本发明涉及电池领域,具体涉及一种电化学装置用隔板、电化学装置及电子装置。
背景技术
锂离子电池具有体积和质量能量密度大、循环寿命长、标称电压高、自放电率低、体积小、重量轻等许多优点,在消费电子领域具有广泛的应用。随着近年来电动汽车和可移动电子设备的高速发展,人们对电池的能量密度、安全性、循环性能等相关需求越来越高,期待着综合性能全面提升的新型锂离子电池的出现。
然而,锂离子电池受限于其固有电化学体系的限制,通常单个电池的工作电压很难超过5V。但在锂离子电池实际使用中,高电压应用场景的需求很多,例如,EV(Electric vehicle,电动汽车)、ESS(Energy Storage System,储能系统)等应用场景。为了提高锂离子电池的输出电压,现有技术通常是将多个电极组件做串联组装。常规的液体电解液电极组件,其串联结构中需要实现串联腔体的离子绝缘功能,避免液态条件下不同电位的阴阳极发生内短路,同时还需规避常规液态电解液在高电压下的分解失效。此外,隔板作为封装结构的一部分,对其机械强度、厚度、热稳定性、电化学稳定性等参数都有一定要求。基于此,常规的单一基础材料难以满足作为串联电极组件隔板的需求,需要开发新的隔板来实现单一电池的串联隔离。目前常用的制备隔板的方法为:一、在耐高温的致密隔离材料表面复合一层封装用的密封材料;二、对耐高温的致密隔离材料表面做改性处理,使隔离材料可与外包装直接紧密粘结,从而实现密封。
但当前技术使用上述第一种方法制得的隔板,普遍为同类高分子材料的多层堆叠,整体厚度较大,材料本身在高温封装条件下易出现结构损伤,离子隔离性能差;使用上述第二种方法制备的隔板,隔板与外包装之间的可靠封装存在困难,具体应用难度大。
发明内容
本发明的目的在于提供一种电化学装置用隔板、电化学装置及电子装置,以提高锂离子电池的封装可靠性。
本发明的第一方面提供一种电化学装置用隔板,其具有离子绝缘性,包括中间层和封装层,所述封装层位于所述中间层的上下两个表面上;
所述中间层的材料包括碳材料、第一高分子材料或金属材料中的至少一种;
所述封装层的材料包括第二高分子材料;
所述封装层开始软化的温度比所述中间层开始软化的温度至少低10℃。
在本发明的一种实施方案中,所述中间层的两个表面的四周边缘被封装层覆盖,所述封装层面积占中间层面积的30%至100%。
在本发明的一种实施方案中,所述中间层的至少一个表面全部被封装层覆盖。
在本发明的一种实施方案中,所述碳材料包括:碳毡、碳膜、炭黑、乙炔黑、富勒烯、导电石墨膜或石墨烯膜中的至少一种。
在本发明的一种实施方案中,所述第一高分子材料包括:聚对苯二甲酸亚乙酯、聚对苯二甲酸丁二醇酯、聚萘二甲酸乙二醇酯、聚醚醚酮、聚酰亚胺、聚酰胺、聚乙二醇、聚酰胺酰亚胺、聚碳酸酯、环状聚烯烃、聚苯硫醚、聚乙酸乙烯酯、聚四氟乙烯,聚亚甲基萘、聚偏二氟乙烯,聚萘二甲酸亚乙酯、聚碳酸亚丙酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)、有机硅、维尼纶、聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯及其共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚苯醚、聚酯、聚砜、非晶态α-烯烃共聚物或上述物质衍生物中的至少一种。
在本发明的一种实施方案中,所述金属材料包括Ni、Ti、Ag、Au、Pt、Fe、Co、Cr、W、Mo、Pb、In、Zn或不锈钢中的至少一种。
在本发明的一种实施方案中,所述第二高分子材料包括:聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯及其共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚酰胺、聚酯、非晶态α-烯烃共聚物或上述物质衍生物中的至少一种。
本发明的第二方面提供了一种电化学装置,所述电化学装置包括至少一个上述的隔板、至少两个电极组件、电解液和外包装,所述电极组件处于独立密封的腔室中。
在本发明的一种实施方案中,所述电极组件的最外层包含隔膜,所述隔膜与所述隔板相邻。
在本发明的一种实施方案中,至少一个所述电极组件的最外层包含隔膜,所述隔膜与所述隔板相邻;至少一个所述电极组件的最外层包含集流体,所述集流体与所述隔板另一侧相邻。
在本发明的一种实施方案中,所述隔板具有电子传导性,所述电极组件的最外层包含集流体,所述集流体与所述隔板相邻,并且所述隔板两侧的电极组件的集流体具有相反的极性。
在本发明的一种实施方案中,所述隔板具有电子绝缘性,所述电极组件的最外层包含集流体,所述集流体与所述隔板相邻。
本发明的第三方面提供了一种电子装置,所述电子装置包括第二方面所述的电化学装置。
本发明提供一种电化学装置用隔板、电化学装置及电子装置,电化学装置用隔板具有离子绝缘性,包括中间层和封装层,封装层位于中间层的上下两个表面上;中间层的材料包括碳材料、第一高分子材料或金属材料中的至少一种;封装层的材料包括第二高分子材料;封装层开始软化的温度比中间层开始软化的温度至少低10℃。通过三层复合膜叠加,可以保证离子绝缘和封装的可靠性。
附图说明
为了更清楚地说明本发明实施例和现有技术的技术方案,下面对实施例和现有技术中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本发明的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图获得其他的附图。
图1为本发明一种实施方案中的隔板截面示意图;
图2为本发明另一种实施方案中的隔板截面示意图;
图3为本发明一种实施方案中的隔板俯视示意图;
图4为本发明一种实施方案中的电极组件封装后的截面示意图;
图5本发明对比例2的电化学装置示意图;
图6为本发明对比例3的电化学装置示意图;
图7为本发明对比例4的电化学装置示意图。
具体实施方式
为使本发明的目的、技术方案、及优点更加清楚明白,以下参照附图并举实施例,对本发明进一步详细说明。显然,所描述的实施例仅仅是本发明一部分实施例,而不是全部的实施例。基于本发明中的实施例,本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例,都属于本发明保护的范围。
需要说明的是,本发明的具体实施方式中,以锂离子电池作为电化学装置的例子来解释本发明,但是本发明的电化学装置并不仅限于锂离子电池。
如图1所示,本发明提供了一种电化学装置用隔板,其具有离子绝缘性,包括中间层2和封装层1,所述封装层1位于所述中间层2的上下两个表面上;
所述中间层2的材料包括碳材料、第一高分子材料或金属材料中的至少一种;
所述封装层1的材料包括第二高分子材料;
所述封装层1开始软化的温度(熔点或软化点)比所述中间层开始软化的温度至少低10℃。
一种电化学装置用隔板,中间层为结构层,具有高机械强度、高熔点或高软化点;两侧为封装层,封装层为低熔点或低软化点。中间层和封装层都具有良好的离子绝缘能力、一定的热稳定性、厚度薄的优点。封装层开始软化的温度比中间层开始软化的温度至少低10℃,可以保证封装的可靠性和离子绝缘的有效性。该隔板可以通过三层不同薄膜热压复合来实现,也可以通过在中间层两侧涂覆封装层的方法来实现。
如图2所示,在本发明的一种实施方案中,所述中间层2的两个表面的四周边缘被封装层1覆盖。即中间层2的主体表面部分不受封装层的遮盖。图3为此种实施方案的俯视示意图。所述封装层面积占中间层面积的30%至100%,所述封装层的绝对宽度大于2mm。
中间层的两个表面的四周边缘被封装层覆盖,尽可能的减少了封装层材料的涂覆量和占比,降低了非有效物质的比例,可以提高电极组件的能量密度。
在本发明的一种实施方案中,所述中间层的至少一个表面全部被封装层覆盖。
在本发明的一种实施方案中,所述碳材料包括碳毡、碳膜、炭黑、乙炔黑、富勒烯、导电石墨膜或石墨烯膜中的至少一种。
在本发明的一种实施方案中,所述第一高分子材料包括聚对苯二甲酸亚乙酯、聚对苯二甲酸丁二醇酯、聚萘二甲酸乙二醇酯、聚醚醚酮、聚酰亚胺、聚酰胺、聚乙二醇、聚酰胺酰亚胺、聚碳酸酯、环状聚烯烃、聚苯硫醚、聚乙酸乙烯酯、聚四氟乙烯,聚亚甲基萘、聚偏二氟乙烯,聚萘二甲酸亚乙酯、聚碳酸亚丙酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)、有机硅、维尼纶、聚丙烯、酸酐改性聚丙烯、聚乙烯、其他乙烯及其共聚物(如EVA、EEA、EAA、EVAL)、聚氯乙烯、聚苯乙烯、其他类聚烯烃、聚醚腈、聚氨酯、聚苯醚、聚酯、聚砜、非晶态α-烯烃共聚物或上述物质衍生物中的至少一种。
中间层采用高分子材料,由于高分子材料的密度小于常用的金属基集流体材料的密度,因此可以降低非活性物质的重量,从而提高电极组件的质量能量密度。中间层采用高分子材料,所制备的隔板相比于金属基集流体,在机械滥用情况(穿钉、撞击、挤压等)下,产生导电碎屑的概率更小,且对机械破损表面包裹效果更好,因此可以改善上述机械滥用情况下的安全边界,提高安全测试通过率。
在本发明的一种实施方案中,所述金属材料包括Ni、Ti、Ag、Au、Pt、Fe、Co、Cr、W、Mo、Pb、In、Zn或不锈钢中的至少一种,优选包括Ni、Ti、Ag、Au、Pt、Fe或不锈 钢中的至少一种。
在本发明的一种实施方案中,所述第二高分子材料包括聚丙烯、酸酐改性聚丙烯、聚乙烯、其他乙烯及其共聚物(如EVA、EEA、EAA、EVAL)、聚氯乙烯、聚苯乙烯、其他类聚烯烃、聚醚腈、聚氨酯、聚酰胺、聚酯、非晶态α-烯烃共聚物或上述物质衍生物中的至少一种。在本发明的一种实施方案中,所述隔板的厚度为2μm至500μm,优选为5μm至50μm,更优选为5μm至20μm。
在本发明的一种实施方案中,所述中间层材料开始软化的温度大于130℃,优选为大于150℃。
在本发明的一种实施方案中,所述封装层材料开始软化的温度为120℃至240℃,优选为130℃至170℃。
需要说明的是,当选择第一高分子材料作为中间层时,本发明所制备的隔板中间层和封装层的材料可以相同或不同,在采用相同材料时,如都为PP(聚丙烯),需要保证中间层和封装层开始软化的温度存在20℃的差异以上。
在本发明的一种实施方案中,封装层与中间层之间的界面粘接力大于10N/cm,优选为大于20N/cm。
在本发明的一种实施方案中,封装层与外包装之间的界面粘接力大于10N/cm,优选为大于15N/cm。
在本发明的一种实施方案中,内未封溢胶区内封装层截面面积与封装区域内封装层截面面积的比例A为0至20,优选为0.5至5,更优选为0.5至2。将锂离子电池的两个极耳正中间的位置切开,取截面,通过SEM(扫描电子显微镜)测试,计算SEM图中的溢胶区面积和封装区面积。按照上述方法测试多个锂离子电池相同位置处的溢胶区面积和封装区面积,得到多个溢胶区面积和封装区面积,然后分别计算溢胶区面积和封装区面积的平均值,两者平均值之比为比例A。图4为封装区域的截面示意图,铝塑膜3中间为封装层,左侧为封装区5,封装区5的胶通过上下铝塑膜3热压将胶挤压到未封区形成溢胶区4。
溢胶区的胶过多时,溢胶区会出现过多的凸起,封装后的电池易破损;溢胶区的胶过少时,热封效果不佳,封装后的电池易破损,所以比例A的值不宜过大或过小。
本发明还提供一种电化学装置,其包括至少一个本发明的隔板、至少两个电极组件、电解液和外包装,所述电极组件处于独立密封的腔室中。
在本发明的一种实施方案中,所述电化学装置包括至少一个本发明的隔板,所述隔板与电化学装置的外包装密封连接,在所述隔板两侧形成两个独立的密封腔室,每个密封腔 室中具有一个电极组件和电解液,形成独立的电化学单元,其中,所述隔板具有电子传导性,所述隔板两侧可以分别涂覆相反极性的电极活性材料。相邻的电化学单元之间通过包含本发明隔板的电极内串联,形成双极性锂离子电池,具有更高的工作电压。
在本发明的一种实施方案中,所述隔板具有电子传导性,相邻的两个电极组件可以各引出一个极耳,这两个电极组件的极耳极性相反,例如,当隔板与电极组件A相邻的一侧涂覆正极活性材料、与电极组件B相邻的一侧涂覆负极活性材料时,电极组件A引出负极极耳,电极组件B引出正极极耳。此时,两个极耳之间的输出电压为两个电化学单元输出电压之和。
在本发明的一种实施方案中,所述隔板具有电子绝缘性,相邻的两个电极组件可以各引出两个极耳,电极组件A的正极极耳与电极组件B的负极极耳串联在一起,电极组件A的负极极耳与电极组件B的正极极耳为输出极耳,输出电压为两个电化学单元输出电压之和。在本发明的一种实施方案中,所述隔板具有电子传导性,隔板可以引出一个极耳,用于监控锂离子电池的工作状态。
在本发明的一种实施方案中,所述电极组件的最外层包含隔膜,所述隔膜与所述隔板相邻。
本发明中,电极组件的最外层根据卷绕或其他方式的收尾,其可以包含隔膜或集流体中的至少一种,例如只包含隔膜、只包含集流体、或者一部分部分包含隔膜,另一部分包含集流体;其中,集流体可以为该最外层未涂布活性物质、部分涂布活性物质或全部表面涂敷活性物质中的至少一种状态。
在本发明的一种实施方案中,本发明的电化学装置包含至少一个隔板,所述隔板可以具有电子绝缘性,也可以具有电子传导性,所述隔板与外包装密封连接,在隔板两侧形成各自独立的密封腔室,每个密封腔室中包含一个电极组件和电解液,形成一个电化学单元,其中,所述隔板两侧直接与相邻的电极组件的隔膜接触并形成电绝缘。此时,两个电极组件各引出两个极耳,两个电极组件之间通过极耳串联连接。
在本发明的一种实施方案中,至少一个所述电极组件的最外层包含隔膜,所述隔膜与所述隔板相邻;至少一个所述电极组件的最外层包含集流体,所述集流体与所述隔板另一侧相邻。
在本发明的一种实施方案中,本发明的电化学装置包含至少一个隔板,所述隔板与外包装密封连接,在隔板两侧形成各自独立的密封腔室,每个密封腔室中包含一个电极组件和电解液,形成一个电化学单元,其中,所述隔板具有电子传导性,所述隔板一侧可以涂 覆电极活性材料,另一侧与电极组件的隔膜相接触形成电绝缘。例如,隔板靠近电极组件A的一侧涂覆正极活性材料,靠近电极组件B的一侧与电极组件B的隔膜接触形成与电极组件B的电绝缘。此时,两个电极组件各引出两个极耳,隔板引出一个极耳,该极耳与电极组件A的正极极耳并联,然后与电极组件B的负极极耳串联。
在本发明的一种实施方案中,本发明的电化学装置包含至少一个隔板,所述隔板与外包装密封连接,在隔板两侧形成各自独立地密封腔室,每个密封腔室中包含一个电极组件和电解液,形成一个电化学单元,所述隔板具有电子绝缘性,所述隔板一侧与电极组件的隔膜接触形成电绝缘,所述隔板的另一侧直接与电极组件的集流体接触。此时,两个电极组件各引出两个极耳,两个电极组件之间通过极耳串联连接。
在本发明的一种实施方案中,所述隔板具有电子传导性,所述电极组件的最外层包含集流体,所述集流体与所述隔板相邻,并且所述隔板两侧的电极组件的集流体具有相反的极性。
在本发明的一种实施方案中,本发明的电化学装置包含至少一个隔板,所述隔板具有电子传导性,所述隔板与外包装密封连接,在隔板两侧形成各自独立的密封腔室,每个密封腔室中包含一个电极组件和电解液,形成一个电化学单元,其中,所述隔板一侧涂覆电极活性材料,另一侧直接与电极组件的集流体相接触并且电连接。例如,隔板靠近电极组件A的一侧涂覆正极活性材料,靠近电极组件B的一侧直接与电极组件B的负极集流体直接接触并且电连接。此时,电极组件A可以引出一个负极极耳,电极组件B可以引出一个正极极耳,两个电化学单元之间通过隔板内串联;或者电极组件A和B各引出两个极耳,电极组件A的正极极耳与电极组件B的负极极耳串联,此时,两个电化学单元之间通过隔板内串联并且通过极耳外部串联。此外,隔板可以引出一个极耳,用于监控电池工作状态。
在本发明的一种实施方案中,所述隔板具有电子绝缘性,所述电极组件的最外层包含集流体,所述集流体与所述隔板相邻。
在本发明的一种实施方案中,本发明的电化学装置包含至少一个隔板,所述隔板与外包装密封连接,在隔板两侧形成各自独立的密封腔室,每个密封腔室中包含一个电极组件和电解液,形成一个电化学单元,其中,所述隔板为电子绝缘体,所述隔板两侧直接与相邻的电极组件的最外层集流体连接,形成电绝缘。此时,两个电极组件各引出两个极耳,两个电极组件之间通过极耳串联连接。
在本发明的一种实施方案中,所述隔板具有电子传导性,在隔板与电极活性材料之间可以包含底涂层,底涂层的作用是改善隔板与活性物质之间的粘接性能,并能够提高隔板 与活性物质之间的电子传导能力。所述底涂层通常是将导电炭黑、丁苯橡胶和去离子水混合后形成的浆料涂覆于隔板上,经烘干后得到的,并且,隔板两面的底涂层可以相同,也可以不同。
本发明还提供一种电子装置,所述电子装置包括上述任一项的电化学装置。
本发明的电极组件没有特别限制,可以使用现有技术的任何电极组件,只要可以实现本发明目的即可,例如可以使用叠片型电极组件或卷绕型电极组件。电极组件一般包括正极极片、负极极片及隔膜。
本发明中的负极极片没有特别限制,只要能够实现本发明目的即可。例如,负极极片通常包含负极集流体和负极活性材料层。其中,负极集流体没有特别限制,可以使用本领域公知的任何负极集流体,例如铜箔、铝箔、铝合金箔以及复合集流体等。负极活性材料层包括负极活性材料,负极活性材料没有特别限制,可以使用本领域公知的任何负极活性材料。例如,可以包括人造石墨、天然石墨、中间相碳微球、软碳、硬碳、硅、硅碳、钛酸锂等中的至少一种。
本发明中的正极极片没有特别限制,只要能够实现本发明目的即可。例如,所述正极极片通常包含正极集流体和正极活性材料。其中,所述正极集流体没有特别限制,可以为本领域公知的任何正极集流体,例如铝箔、铝合金箔或复合集流体等。所述正极活性材料没有特别限制,可以为现有技术的任何正极活性材料,所述活性物质包括NCM811、NCM622、NCM523、NCM111、NCA、磷酸铁锂、钴酸锂、锰酸锂、磷酸锰铁锂或钛酸锂中的至少一种。
本发明中的电解液没有特别限制,可以使用本领域公知的任何电解液,例如可以是凝胶态、固态和液态中的任一种,例如,液态电解液可以包括锂盐和非水溶剂。
锂盐没有特别限制,可以使用本领域公知的任何锂盐,只要能实现本发明的目的即可。例如,锂盐可以包括六氟磷酸锂(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 3SO 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。例如,锂盐可选用LiPF 6
非水溶剂没有特别限定,只要能实现本发明的目的即可。例如,非水溶剂可以包括碳酸酯化合物、羧酸酯化合物、醚化合物、腈化合物或其它有机溶剂中的至少一种。
例如,碳酸酯化合物可以包括碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸甲乙酯(EMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)、 碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)、碳酸乙烯基亚乙酯(VEC)、碳酸氟代亚乙酯(FEC)、碳酸1,2-二氟亚乙酯、碳酸1,1-二氟亚乙酯、碳酸1,1,2-三氟亚乙酯、碳酸1,1,2,2-四氟亚乙酯、碳酸1-氟-2-甲基亚乙酯、碳酸1-氟-1-甲基亚乙酯、碳酸1,2-二氟-1-甲基亚乙酯、碳酸1,1,2-三氟-2-甲基亚乙酯或碳酸三氟甲基亚乙酯中的至少一种。
本发明中的隔膜没有特别限制,例如,隔膜包括由对本发明的电解液稳定的材料形成的聚合物或无机物等。隔膜一般应当具有离子传导性和电子绝缘性。
例如隔膜可包括基材层和表面处理层。基材层可以为具有多孔结构的无纺布、膜或复合膜,基材层的材料可以选自聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰亚胺中的至少一种。任选地,可以使用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。任选地,基材层的至少一个表面上设置有表面处理层,表面处理层可以是聚合物层或无机物层,也可以是混合聚合物与无机物所形成的层。
例如,无机物层包括无机颗粒和粘结剂,所述无机颗粒没有特别限制,例如可以选自氧化铝、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、氢氧化钙和硫酸钡中的至少一种。所述粘结剂没有特别限制,例如可以选自聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的一种或几种的组合。聚合物层中包含聚合物,聚合物的材料包括聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯或聚(偏氟乙烯-六氟丙烯)中的至少一种。
本发明还提供了一种隔板的制备方法,可以用来制备上述封装层全部涂覆中间层的隔板,包括以下步骤:
(1)将封装层材料均匀分散到分散剂中,制备得到封装层悬浊液;
(2)利用流延设备,在中间层两侧分别流延所得悬浊液,制备封装层;
(3)烘干封装层悬浊液中的分散剂,即完成了隔板的制备。
本发明还提供了一种隔板的制备方法,可以用来制备上述封装层全部涂覆中间层的隔板,包括以下步骤:
(1)将封装层材料均匀分散到分散剂中,制备得到封装层悬浊液;
(2)将中间层中材料均匀分散到分散剂中,制备得到中间层悬浊液;
(3)利用流延设备,将中间层和两侧封装层悬浊液同步流延制备;
(4)烘干封装层和中间层悬浊液中的分散剂,即完成了隔板的制备。
本发明还提供了一种隔板的制备方法,可以用来制备上述封装层四周涂覆中间层的隔板,包括以下步骤:
(1)将封装层材料均匀分散到分散剂中,制备得到封装层悬浊液;
(2)利用涂胶机,在中间层两侧分别制备封装层;
(3)烘干封装层悬浊液中的分散剂,即完成了隔板的制备。
本发明还提供了一种隔板的制备方法,可以用来制备上述封装层四周涂覆中间层的隔板,包括以下步骤:
(1)将封装层材料均匀分散到分散剂中,制备得到封装层悬浊液;
(2)利用3D打印机,在中间层两侧分别制备封装层;
(3)烘干封装层悬浊液中的分散剂,即完成了隔板的制备。
本发明对所述分散剂没有特别限制,可以为本领域常用的极性有机溶剂,例如可以为NMP(N-甲基吡咯烷酮)、DMF(N,N-二甲基甲酰胺)、THF(四氢呋喃)等。
以下,举出实施例及比较例来对本发明的实施方式进行更具体地说明。各种的试验及评价按照下述的方法进行,另外,只要无特别说明,“份”、“%”为重量基准。
实施例
制备例1:负极极片的制备
将负极活性材料石墨、导电炭黑、丁苯橡胶按照质量比96:1.5:2.5进行混合,加入去离子水作为溶剂,调配成为固含量为70%的浆料,搅拌均匀。将浆料均匀涂覆在厚度为10μm的铜箔的一个表面上,110℃条件下烘干,得到涂层厚度为150μm层厚的单面涂覆负极活性材料层的负极极片,然后在该负极极片的另一个表面上重复以上涂覆步骤。涂覆完成后,将极片裁切成41mm×61mm的规格并焊接极耳后待用。
制备例2:正极极片的制备
将正极活性材料LiCoO 2、导电炭黑、PVDF(聚偏氟乙烯)按照质量比97.5:1.0:1.5进行混合,加入NMP作为溶剂,调配成为固含量为75%的浆料,搅拌均匀。将浆料均匀涂覆在厚度为12μm,的铝箔的一个表面上,90℃条件下烘干,得到涂层厚度为100μm的单面涂覆正极活性材料层的正极极片。然后在该正极极片的另一个表面上重复以上步骤。涂覆完成后,将极片裁切成38mm×58mm的规格并焊接极耳待用。
制备例3:电解液的制备
在干燥氩气气氛中,首先将有机溶剂EC(碳酸乙烯酯)、EMC(碳酸甲乙酯)和DEC(碳酸二乙酯)以质量比EC:EMC:DEC=30:50:20混合,然后向有机溶剂中加入LiPF 6 (六氟磷酸锂)溶解并混合均匀,得到锂盐浓度为1.15M的电解液。
制备例4:电极组件的制备
选用厚度15μm的PE(聚乙烯)膜作为隔离膜,在制备例1的负极极片的两面分别放置一片制备例2的正极极片,正极极片与负极极片之间放置一层隔离膜,组成叠片,然后将整个叠片结构的四个角固定好,引出正极极耳和负极极耳,得到电极组件A。
选用厚度15μm的PE膜作为隔离膜,正极极片的两面分别放置一片负极极片,正极极片与负极极片之间放置一层隔离膜,组成叠片,然后将整个叠片结构的四个角固定好,引出正极极耳和负极极耳,得到电极组件B。
实施例1
隔板的制备
(1)将封装层中的封装用物质PP均匀分散到分散剂NMP(N-甲基吡咯烷酮)中,得到封装层悬浊液,悬浊液的浓度为45wt%;
(2)利用涂胶机,在厚度为20μm的中间层PET(聚对苯二甲酸乙二醇酯)薄膜两个表面的四周边缘制备厚度为40μm的封装层PP,封装层PP的宽为5mm,中间层PET开始软化的温度为270℃,封装层PP开始软化的温度为150℃,封装层厚度的压缩率为70%。
(3)130℃烘干封装层悬浊液中的分散剂NMP,即完成了隔板的制备。
通过调整封装时间、封装压力、封装温度等参数来调整各个实施例的封装层厚度的压缩率,具体参见表1。
电极组件的组装
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,然后将隔板置于电极组件A上,隔板一侧与电极组件A的隔膜接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将制备例4的电极组件B置于隔板之上,隔板另一侧与电极组件B的隔膜接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
电极组件注液封装
将制备例3的电解液分别注入上述组装电极组件的两个腔体后封装,两个电极组件的 极耳都引出外包装,将电极组件A的正极极耳与电极组件B的负极极耳焊接在一起,实现两电极组件之间串联导通。
实施例2
除了隔板的制备过程中封装层厚度的压缩率为40%以外,其余与实施例1相同。
实施例3
除了隔板的制备过程中封装层厚度的压缩率为20%以外,其余与实施例1相同。
实施例4
除了隔板的制备过程中封装层材料使用PP,中间层材料使用PP,封装层开始软化的温度为130℃,中间层开始软化的温度为150℃、封装层厚度的压缩率为40%以外,其余与实施例1相同。
实施例5
除了隔板的制备过程中中间层材料使用PI(聚酰亚胺),中间层开始软化的温度为334℃、封装层厚度的压缩率为40%以外,其余与实施例1相同。
实施例6
除了隔板的制备过程中封装层材料使用PS(聚苯乙烯),中间层材料使用不锈钢,封装层开始软化的温度为240℃,中间层开始软化的温度为1440℃、封装层厚度的压缩率为40%以外,其余与实施例1相同。
实施例7
除了隔板的制备过程中,中间层材料使用PI,中间层开始软化的温度为334℃,封装层厚度的压缩率为40%,封装层与中间层的界面粘接力为28N/m,封装层与外包装的界面粘接力为17.3N/m以外,其余与实施例1相同。
实施例8
除了隔板的制备过程中,封装层材料使用PS,中间层材料使用PI,封装层开始软化的温度为240℃,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%以外,其余与实施例1相同。
实施例9
除了隔板的制备过程中,中间层材料使用PI,中间层材料开始软化的温度为334℃,比例A为0以外,其余与实施例1相同。
实施例10
除了隔板的制备过程中,中间层材料使用PI,中间层材料开始软化的温度为334℃, 比例A为0.1以外,其余与实施例1相同。
实施例11
除了隔板的制备过程中,中间层材料使用PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%,比例A为1.5以外,其余与实施例1相同。
实施例12
除了隔板的制备过程中,中间层材料使用PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为20%,比例A为20以外,其余与实施例1相同。
在实施例9-12中,通过调节封装涂胶区的涂胶宽度,调节比例A的大小,涂胶宽度越小,A值越小。
实施例13
除了隔板的制备过程中,中间层材料使用Al,封装层材料开始软化的温度为130℃,中间层材料开始软化的温度为660℃、封装层厚度的压缩率为40%以外,其余与实施例1相同。
实施例14
除了隔板的制备过程中,中间层材料使用碳膜,中间层开始软化的温度为3500℃、封装层厚度的压缩率为40%,其余与实施例1相同。
实施例15
除了隔板的制备过程中,中间层材料使用PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%,中间层厚度为1000μm以外,其余与实施例1相同。
实施例16
除了隔板的制备过程中,中间层材料使用PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%,中间层厚度为10μm以外,其余与实施例1相同。
实施例17
除了隔板的制备:中间层材料使用PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%,中间层厚度为2μm以外,其余与实施例1相同。
实施例18
除了隔板的制备:中间层材料使用PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%;
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将 制备例4的电极组件A置于坑内,然后将隔板置于电极组件A上,隔板一侧与电极组件A的隔膜接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将制备例4的电极组件B置于隔板之上,隔板另一侧与电极组件B的集流体接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
其余与实施例1相同。
实施例19
除了隔板的制备过程中,中间层的材料为不锈钢,中间层的熔点为1440℃、封装层厚度的压缩率为40%;
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,使电极组件A的正极极片朝上,放置隔板于电极组件A上,隔板一侧与电极组件A的正极集流体接触,施加外力压紧。
将上述组装半成品置于组装夹具内,隔板朝上,将制备例4的电极组件B负极朝下置于隔板之上,隔板另一侧与电极组件B的负极集流体接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
电极组件注液封装:
将制备例3的电解液分别注入组装电极组件的两个腔体后封装,电极组件A和B的极耳都引出外包装,两个电化学单元之间通过隔板内串联,得到锂离子电池。
其余与实施例1相同。
实施例20
除了隔板的制备:中间层材料为PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%;
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,然后将隔板置于电极组件A上,隔板一侧与电极组件A 的集流体接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将制备例4的电极组件B置于隔板之上,隔板另一侧与电极组件B的集流体接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
其余与实施例1相同。
实施例21
除了隔板的制备:中间层材料为PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%,中间层两侧全部涂覆PP。
隔板的制备步骤为:
(1)将封装层中的封装用物质PP均匀分散到分散剂NMP(N-甲基吡咯烷酮)中,制备得到封装层悬浊液,悬浊液的浓度为45wt%;
(2)利用涂胶机,在厚度为20μm的中间层PI(聚酰亚胺)薄膜两侧均匀制备厚度为30μm的封装层PP,中间层PI开始软化的温度为334℃,封装层PP开始软化的温度为150℃;
(3)130℃烘干封装层悬浊液中的分散剂NMP,即完成了隔板的制备。
其余与实施例1相同。
实施例22
除了隔板的制备:中间层材料为PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%,中间层两侧全部涂覆PP。
隔板的制备步骤为:
(1)将封装层中的封装用物质PP均匀分散到分散剂NMP(N-甲基吡咯烷酮)中,制备得到封装层悬浊液,悬浊液的浓度为45wt%;
(2)利用涂胶机,在厚度为20μm的中间层PI(聚酰亚胺)薄膜两侧均匀制备厚度为30μm的封装层PP,中间层PI开始软化的温度为334℃,封装层PP开始软化的温度为150℃;
(3)130℃烘干封装层悬浊液中的分散剂NMP,即完成了隔板的制备。
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,然后将隔板置于电极组件A上,隔板一侧与电极组件A的隔膜接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将制备例4的电极组件B置于隔板之上,隔板另一侧与电极组件B的集流体接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
其余与实施例1相同。
实施例23
除了隔板的制备:中间层材料为PI,中间层材料开始软化的温度为334℃、封装层厚度的压缩率为40%,中间层两侧全部涂覆PP。
隔板的制备步骤为:
(1)将封装层中的封装用物质PP均匀分散到分散剂NMP(N-甲基吡咯烷酮)中,制备得到封装层悬浊液,悬浊液的浓度为45wt%;
(2)利用涂胶机,在厚度为20μm的中间层PI(聚酰亚胺)薄膜两侧均匀制备厚度为30μm的封装层PP,中间层PI开始软化的温度为334℃,封装层PP开始软化的温度为150℃;
(3)130℃烘干封装层悬浊液中的分散剂NMP,即完成了隔板的制备。
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,然后将隔板置于电极组件A上,隔板一侧与电极组件A的集流体接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将制备例4的电极组件B置于隔板之上,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,隔板另一侧与电极组件B的集流体接触,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
其余与实施例1相同。
实施例24
除了隔板的制备:中间层为不锈钢,熔点为1440℃、封装层厚度的压缩率为40%。
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,然后将隔板置于电极组件A上,隔板一侧与电极组件A 的隔膜接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将制备例4的电极组件B置于隔板之上,隔板另一侧与电极组件B的正极集流体接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
电极组件注液封装:
将制备例3的电解液分别注入组装电极组件的两个腔体后封装,两个电极组件的极耳都引出外包装,将电极组件A的正极极耳与电极组件B的负极极耳焊接在一起,实现两电极组件之间串联导通。隔板的该极耳与电极组件A的正极极耳并联,然后与电极组件B的负极极耳串联,得到锂离子电池。
其余与实施例1相同。
实施例25
除了隔板的制备:封装层厚度的压缩率为40%;
电极组件的制备:
将双面涂覆负极极片、第一隔膜、双面涂覆正极极片、第二隔膜依次层叠设置组成叠片,然后将整个叠片进行卷绕,引出正极极耳和负极极耳,第一隔膜置于最外侧。其中,隔膜选用厚度15μm的聚乙烯(PE)膜,负极极片通过制备例1制得,正极极片通过制备例2制得。制得电极组件A。
将双面涂覆负极极片、第一隔膜、双面涂覆正极极片、第二隔膜依次层叠设置组成叠片,然后将整个叠片卷绕,引出正极极耳和负极极耳,第二隔膜置于最外侧,负极极片通过制备例1制得,正极极片通过制备例2制得。其中,隔膜选用厚度15μm的聚乙烯(PE)膜。制得电极组件B。
其余与实施例1相同。
实施例26
除了隔板的制备:中间层材料为不锈钢,熔点为1440℃,封装层厚度的压缩率为40%;
电极组件的制备:
将双面涂覆负极极片、第一隔膜、双面涂覆正极极片、第二隔膜依次层叠设置组成叠片,然后将整个叠片进行卷绕,引出正极极耳和负极极耳,第一隔膜置于最外侧。其中,隔膜选用厚度15μm的聚乙烯(PE)膜,负极极片通过制备例1制得,正极极片通过制备 例2制得。制得电极组件A。
将双面涂覆负极极片、第一隔膜、双面涂覆正极极片、第二隔膜依次层叠设置组成叠片,然后将整个叠片卷绕,引出正极极耳和负极极耳,正极极片的正极集流体置于最外侧。其中,隔膜选用厚度15μm的聚乙烯(PE)膜,负极极片通过制备例1制得,正极极片通过制备例2制得。制得电极组件B。
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将上述电极组件A置于坑内,然后将隔板置于电极组件A上,隔板一侧与电极组件A的第一隔膜接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将上述电极组件B置于隔板之上,隔板另一侧与电极组件B的正极集流体接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
电极组件注液封装:
将制备例3的电解液分别注入组装电极组件的两个腔体后封装,两个电极组件的极耳都引出外包装,将电极组件A的正极极耳与电极组件B的负极极耳焊接在一起,实现两电极组件之间串联导通。
其余与实施例1相同。
实施例27
除了隔板的制备:中间层材料为不锈钢,熔点为1440℃,封装层厚度的压缩率为40%;
电极组件的制备:
将双面涂覆负极极片、隔膜、双面涂覆正极极片依次层叠设置组成叠片,然后将整个叠片进行卷绕,引出正极极耳和负极极耳,负极极片的负极集流体置于最外侧。其中,隔膜选用厚度15μm的聚乙烯(PE)膜,负极极片通过制备例1制得,正极极片通过制备例2制得。制得电极组件A。
将双面涂覆负极极片、隔膜、双面涂覆正极极片依次层叠设置组成叠片,然后将整个叠片卷绕,引出正极极耳和负极极耳,正极极片的正极集流体置于最外侧。其中,隔膜选用厚度15μm的聚乙烯(PE)膜,负极极片通过制备例1制得,正极极片通过制备例2制得。制得电极组件B。
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将上述电极组件A置于坑内,使电极组件A的正极极片朝上,放置隔板于电极组件A上,隔板一侧与电极组件A的负极集流体接触,施加外力压紧。
将上述组装半成品置于另一组装夹具内,隔板朝上,将上述电极组件B负极朝下置于隔板之上,隔板另一侧与电极组件B的正极集流体接触,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与隔板一起热封,使电极组件A和电极组件B被隔板分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
电极组件注液封装:
将制备例3的电解液分别注入组装电极组件的两个腔体后封装,电极组件A和B的极耳都引出外包装,两个电化学单元之间通过隔板内串联,得到锂离子电池。
其余与实施例1相同。
对比例1
单电极锂离子电池
将制备例2的正极极片与制备例1的负极极片叠放在一起,正极极片和负极极片之间具有厚度15μm的PE隔膜,使用铝箔包装,进行封装注入制备例3的电解液,正负极极片的极耳引出外包装。得到锂离子电池。
对比例2
两独立电极组件外部串联,如图5所示,
电极组件注液封装:
将制备例4的电极组件A、B分别四个角固定,使用铝塑膜包装,再将包装四周密封;分别给铝塑膜中注入制备例3的电解液,将电极组件A和B的所有极耳引出铝塑膜外。将电极组件A的正极极耳和电极组件B的负极极耳通过激光焊的方式焊接连接在一起,实现电极组件A和B之间的串联导通,电池组装完成。
对比例3
两独立电极组件头尾串联,如图6所示,
电极组件组装与注液封装:
在制备例4电极组件的正极极耳涂覆密封胶,将电极组件A负极与电极组件B正极极耳焊接,实现电极组件A和电极组件B的电极串联,将串联完毕后的电极组件封入成型的 铝塑膜中。封装时除外轮廓顶侧密封外,每个电极组件之间沿正极密封胶处,在电极组件宽度方向上进行密封封装,实现每个电极组件之间腔体的隔离,将制备例3的电解液分别注入两电极组件所在的腔体中。封装后电极组件长度方向上一侧引出正极极耳,一侧引出负极极耳,其余串联极耳均处于电极组件外包装内。
对比例4
两独立电极组件并排串联,如图7所示,
电极组件的组装:
将制备例4的电极组件A放入成型的铝塑膜中一侧,盖上上层铝塑膜,压紧有电极组件A的一侧;在已放入电极组件A的铝塑膜边界位置涂覆胶水并将上下层铝塑膜压紧,沿电极组件长度方向从电极组件尾部涂至顶部封装区域,凝固成型。
在上述半成品中,电极组件A的侧面空置区域中放入制备例4的电极组件B,对整个铝塑膜进行顶部封装。顶部封装与胶水涂覆区域垂直相交,接触密封,使电极组件A和B分别处于独立地密封腔体内。
电极组件注液封装
分别对两个电极组件所在腔体注入制备例3的电解液,并对铝塑膜进行密封,两电极组件的极耳都引出外包装,将电极组件A的正极极耳与电极组件B的负极极耳焊接。确保两电极组件处于两独立密封腔体内,电解液无交换可能。
对比例5
单包装袋厚度堆叠无隔板
电极组件的组装:
将冲坑成型的包装膜,包装膜为铝塑膜,厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,将制备例4的电极组件B置于电极组件A之上,电极组件A和电极组件B之间以隔膜分隔,压紧。后将另一片包装膜坑面朝下覆盖于电极组件B之上,热封四周。
电极组件注液封装:
对两电极组件所在腔体注入制备例3的电解液,注液后进行四周封装,电极组件的正负极耳均引出外包装,各极耳错位分布,避免极耳厚度方向堆叠导致密封失效。
将电极组件A的正极极耳与电极组件B的负极极耳焊接在一起,实现两电极组件之间串联导通。
对比例6
隔板使用常见的单层PP隔膜直接作为隔板,厚度为20μm,开始软化的温度为165℃;
电极组件的组装:
将冲坑成型的包装膜(铝塑膜),厚度为90μm,置于组装夹具内,坑面朝上,然后将制备例4的电极组件A置于坑内,然后将PP隔膜置于电极组件A上,施加外力压紧。
将上述组装半成品置于另一组装夹具内,将制备例4的电极组件B置于PP隔膜之上,然后将冲坑成型的另一厚度为90μm的铝塑膜坑面朝下覆盖于电极组件B之上,再采用热压的方式将两个铝塑膜与PP隔膜一起热封,使电极组件A和电极组件B被PP隔膜分隔,得到组装电极组件。该组装电极组件具有两个独立的腔体,其中,电极组件A对应第一腔体,电极组件B对应第二腔体。
电极组件注液封装
对两电极组件所在腔体注入制备例3的电解液,注液后进行四周封装,电极组件的正负极耳均引出外包装,将电极组件A的正极极耳与电极组件B的负极极耳焊接在一起,实现两电极组件之间串联导通。
对比例7
除了使用单层PP作为隔板,隔板厚度为20μm,开始软化的温度为165℃,其余与对比例6相同。
对比例8
除了使用单层PI作为隔板,隔板厚度为20μm,开始软化的温度为334℃,其余与对比例6相同。
对比例9
除了使用单层不锈钢作为隔板,隔板厚度为20μm,熔点为1440℃,其余与对比例6相同。
<性能测试>
使用下述方法对各实施例及各对比例制得的电化学装置用隔板、双极性锂离子电池进行测试:
封装层与中间层的界面粘结力F 1测试
1)从电极组件中取下封印区域部分,作为样品1;
2)将样品1在液氮中冷却,并将封装层一侧的外包装磨掉,使得封装层与中间层的界面露出;
3)将样品1裁剪为宽度为8mm,长度为6cm的试条,保证在此区域内,封装层完全 覆盖中间层,得到样品2;
4)在样品2封装层表面粘贴高粘高强度胶纸;
5)使用高铁拉力机,以90°角将高粘高强度胶纸从样品2表面缓慢撕下,使得封装层与中间层的界面分离;
6)记录上述界面分离时的稳定拉力,并以此为基础计算得到封装层与中间层的界面粘接力。
封装层与外包装的界面粘接力F 2测试
1)从电极组件中取下封印区域部分,作为样品1;
2)将样品1在液氮中冷却,并将封装层一侧的中间层磨掉,使得封装层与外包装的界面露出;
3)将样品1裁剪为宽度为8mm,长度为6cm的试条,保证在此区域内,封装层完全覆盖外包装,得到样品2;
4)在样品2涂胶层表面粘贴高粘高强度胶纸;
5)使用高铁拉力机,以90°角将高粘高强度胶纸从样品2表面缓慢撕下,使得封装层与外包装的界面分离;
6)记录上述界面分离时的稳定拉力,并以此为基础计算得到封装层与外包装的界面粘接力。
封装强度测试
1)从电极组件中取下封印区域部分,作为样品1;
2)将样品1裁剪为宽度为8mm的试条,保证此试条完整保存了整个封印区域,同时封印区两侧的外包装也完好无损,得到样品2;
3)使用高铁拉力机,以180°角将两侧的外包装撕开,使得封装区域内两层外包装相互分离;
4)记录上述两层外包装分离时的稳定拉力,并以此为基础计算得到封装强度。
1.5米跌落测试封装处破损情况测试
1)将测试后的电极组件样品拆解,并将封印区单独取下备用;
2)在封印区滴加红药水,并使得空间维度红药水在上方,封印区在下方,静置12h;
3)随后通过封装强度测试将封印区破坏,观察红药水渗入封印区的情况;
4)如存在红药水渗入封印区域的深度超过封印区域宽度的1/2,即判定为封装处破损,反之则判定为封装处未破损。
放电能量密度ED测试
将锂离子电池在常温下静置30分钟,以0.05C充电速率恒流充电至电压4.45V(对比例1额定电压)或8.90V(其他对比例及所有实施例额定电压),随后再以0.05C倍率将电化学装置放电至3.00V(对比例1额定电压)或6.00V(其他对比例及所有实施例),重复上述充/放电步骤3个循环以完成待测的电化学装置的化成。完成电化学装置的化成后,以0.1C充电速率恒流充电至电压至4.45V(对比例1额定电压)或8.90V(其他对比例及所有实施例),随后以0.1C放电倍率将电化学装置放电至3.00V(对比例1额定电压)或6.00V(其他对比例及所有实施例),纪录其放电容量,随后计算其0.1C放电时的能量密度:
能量密度(Wh/L)=放电容量(Wh)/锂离子电池体积尺寸(L)
50次循环后的放电容量/首次放电容量Q 50/Q 0(%)测试
测试温度为25℃,以0.5C恒流充电到4.45V(对比例1额定电压)或8.90V(其他对比例及所有实施例),恒压充电到0.025C,静置5分钟后以0.5C放电到3.00V(对比例1额定电压)或6.00V(其他对比例及所有实施例),以此步得到的容量为初始容量,再以0.5C充电/0.5C放电循环测试50次后,计算锂离子电池的容量与初始容量的比值。
3C充电温升测试
测试温度为25℃,以3C恒流充电到4.45V(对比例1额定电压)或8.90V(其他对比例及所有实施例),恒压充电到0.025C。过程中在电芯正上方中心处放置热电偶,实时测试充电过程中的温度变化,记录上述温度最高值减去测试温度25℃即为3C充电温升。
穿钉通过率测试
将待测的锂离子电池以0.05C的倍率恒流充电至电压为4.45V(对比例1额定电压)或8.90V(其他对比例及所有实施例),随后恒压充电至电流为0.025C(截止电流),使电池达到满充状态,记录测试前电池外观。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,穿钉位置分别位于距离Al极耳电极组件边缘15mm处和距离Ni极耳电极组件边缘15mm处,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10个电极组件为一组,观察测试过程中电池状态,以电池不燃烧,不爆炸为判定标准,10次穿钉测试通过9次以上判定为通过穿钉测试。
表1各实施例及对比例的测试参数以及相应的实验结果
Figure PCTCN2020099432-appb-000001
Figure PCTCN2020099432-appb-000002
如表1所示,相较于对比例2-4,除实施例15以外,本发明实施例的能量密度增大,可以看出本发明实施例的隔板串联结构锂离子电池比现有的两独立电极组件外部串联结构锂离子电池、两独立电极组件头尾串联结构锂离子电池、两独立电极组件并排串联结构锂离子电池具有更高的能量密度(NG表示未测得)。
相较于对比例1-9,本发明实施例1-5,7,11-27的封装强度增加,同时本发明实施例1-5、7-12、15-16、18、20-23、25的穿钉通过比例高于对比例1-4及9;
相较于对比例1-2,本发明实施例1-10,12-14,16-17,19,24-27跌落破损比例增加,但是对比例1单电极组件锂离子电池的放电电压低,对比例2两独立电极组件外部串联结构锂离子电池,需要两个电极组件的放电电压相近,否则容易发生短路,并且本发明实施例11、15、18、20-23依然与对比例1-2有相同的跌落破损比例;相较于对比例3-4,本发明实施例1-5,7,11-12,15-18,20-23,25的跌落破损比例降低,说明相对于现有的两独立电极组件头尾串联结构锂离子电池、两独立电极组件并排串联结构锂离子电池具有更低的跌落破损比例;相较于对比例8-9,本发明实施例的跌落破损比例明显降低,说明本发明制备的隔板应用于锂离子电池中可以很好的抗跌落损坏。
除了相较于对比例1,单电极锂离子电池,本发明实施例的3C充电温升降低以外,相较于对比例2-4及7-9,本发明实施例的充电温升基本不发生变化。
相较于对比例,本发明实施例的50次循环后的放电容量与首次放电容量的比值基本不发生变化。
可以看出本发明所制备的隔板应用于锂离子电池中可以提高锂离子电池的封装可靠性,取得了很好的技术效果。
以上所述仅为本发明的较佳实施例,并不用以限制本发明,凡在本发明的精神和原则之内,所做的任何修改、等同替换、改进等,均应包含在本发明保护的范围之内。

Claims (17)

  1. 一种电化学装置用隔板,其具有离子绝缘性,包括中间层和封装层,所述封装层位于所述中间层的上下两个表面上;
    所述中间层的材料包括碳材料、第一高分子材料或金属材料中的至少一种;
    所述封装层的材料包括第二高分子材料;
    所述封装层开始软化的温度比所述中间层开始软化的温度至少低10℃。
  2. 根据权利要求1所述的隔板,其中,所述中间层的两个表面的四周边缘被封装层覆盖,所述封装层面积占中间层面积的30%至100%。
  3. 根据权利要求2所述的隔板,其中,所述中间层的至少一个表面全部被封装层覆盖。
  4. 根据权利要求1所述的隔板,其中,所述碳材料包括碳毡、碳膜、炭黑、乙炔黑、富勒烯、导电石墨膜或石墨烯膜中的至少一种。
  5. 根据权利要求1所述的隔板,其中,所述第一高分子材料包括:聚对苯二甲酸亚乙酯、聚对苯二甲酸丁二醇酯、聚萘二甲酸乙二醇酯、聚醚醚酮、聚酰亚胺、聚酰胺、聚乙二醇、聚酰胺酰亚胺、聚碳酸酯、环状聚烯烃、聚苯硫醚、聚乙酸乙烯酯、聚四氟乙烯,聚亚甲基萘、聚偏二氟乙烯,聚萘二甲酸亚乙酯、聚碳酸亚丙酯、聚(偏二氟乙烯-六氟丙烯)、聚(偏二氟乙烯-共-三氟氯乙烯)、有机硅、维尼纶、聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯及其共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚苯醚、聚酯、聚砜、非晶态α-烯烃共聚物或上述物质衍生物中的至少一种。
  6. 根据权利要求1所述的隔板,其中,所述金属材料包括Ni、Ti、Ag、Au、Pt、Fe、Co、Cr、W、Mo、Pb、In、Zn或不锈钢中的至少一种。
  7. 根据权利要求1所述的隔板,其中,所述第二高分子材料包括:聚丙烯、酸酐改性聚丙烯、聚乙烯、乙烯及其共聚物、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨酯、聚酰胺、聚酯、非晶态α-烯烃共聚物或上述物质衍生物中的至少一种。
  8. 根据权利要求1所述的隔板,其中,所述隔板的厚度为2μm至500μm。
  9. 根据权利要求1所述的隔板,其中,所述中间层材料开始软化的温度大于130℃。
  10. 根据权利要求1所述的隔板,其中,所述封装层材料开始软化的温度为120℃至240℃。
  11. 根据权利要求1所述的隔板,其具有以下特征中的至少一个:
    (a)所述隔板的厚度为5μm至50μm;
    (b)所述中间层材料开始软化的温度大于150℃;
    (c)所述封装层材料开始软化的温度为130℃至170℃。
  12. 一种电化学装置,所述电化学装置包括至少一个根据权利要求1-11的任一项所述的隔板、至少两个电极组件、电解液和外包装,所述电极组件处于独立密封的腔室中。
  13. 根据权利要求12所述的电化学装置,其中,所述电极组件的最外层包含隔膜,所述隔膜与所述隔板相邻。
  14. 根据权利要求12所述的电化学装置,其中,至少一个所述电极组件的最外层包含隔膜,所述隔膜与所述隔板相邻;至少一个所述电极组件的最外层包含集流体,所述集流体与所述隔板另一侧相邻。
  15. 根据权利要求12所述的电化学装置,其中,所述隔板具有电子传导性,所述电极组件的最外层包含集流体,所述集流体与所述隔板相邻,并且所述隔板两侧的电极组件的集流体具有相反的极性。
  16. 根据权利要求12所述的电化学装置,其中,所述隔板具有电子绝缘性,所述电极组件的最外层包含集流体,所述集流体与所述隔板相邻。
  17. 一种电子装置,所述电子装置包括权利要求12-16任一项所述的电化学装置。
PCT/CN2020/099432 2020-06-30 2020-06-30 一种电化学装置用隔板、电化学装置及电子装置 WO2022000314A1 (zh)

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