WO2022000307A1 - 一种电化学装置及包含该电化学装置的电子装置 - Google Patents

一种电化学装置及包含该电化学装置的电子装置 Download PDF

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Publication number
WO2022000307A1
WO2022000307A1 PCT/CN2020/099419 CN2020099419W WO2022000307A1 WO 2022000307 A1 WO2022000307 A1 WO 2022000307A1 CN 2020099419 W CN2020099419 W CN 2020099419W WO 2022000307 A1 WO2022000307 A1 WO 2022000307A1
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Prior art keywords
current collector
bipolar current
electrode assembly
electrochemical device
electrode
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PCT/CN2020/099419
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English (en)
French (fr)
Inventor
张楠
张益博
严坤
胡乔舒
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宁德新能源科技有限公司
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Priority to CN202080100167.9A priority Critical patent/CN115461909A/zh
Priority to PCT/CN2020/099419 priority patent/WO2022000307A1/zh
Publication of WO2022000307A1 publication Critical patent/WO2022000307A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/06—Lead-acid accumulators
    • H01M10/18—Lead-acid accumulators with bipolar electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of electrochemistry, and in particular, to an electrochemical device and an electronic device including the electrochemical device.
  • Lithium-ion batteries have many advantages such as high energy density, long cycle life, high nominal voltage, low self-discharge rate, small size, and light weight, and are widely used in consumer electronics. With the rapid development of electric vehicles (EVs) 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 development of new lithium-ion batteries with comprehensive performance improvements Appear.
  • EVs electric vehicles
  • EVs electric vehicles
  • mobile electronic devices people have higher and higher requirements for battery energy density, safety, cycle performance, etc., and look forward to the development of new lithium-ion batteries with comprehensive performance improvements Appear.
  • the operating voltage of the lithium-ion battery is difficult to exceed 5V.
  • 5V voltage electric vehicles (EV), voltage transformers (PT), energy storage systems (ESS) and so on.
  • EV electric vehicles
  • PT voltage transformers
  • ESS energy storage systems
  • this series connection method needs to weld the different polarities of different lithium-ion batteries to realize the series connection of lithium-ion batteries, and the poor welding effect of the electrodes can easily lead to problems such as increasing the internal resistance of the lithium-ion battery, which not only has great problems. It is a safety hazard and is not conducive to the output of electric energy. At the same time, the design of multiple tab lead-out pieces will increase the risk of tab breakage, thereby reducing the production yield. Therefore, developing a new lithium-ion battery with a series structure to achieve high output voltage battery reliability and effective output of electric energy has become an urgent problem for those skilled in the art.
  • a first aspect of the present application provides an electrochemical device comprising a bipolar current collector and an electrode assembly, the electrode assemblies are located on both sides of the bipolar current collector, and the electrode assemblies on both sides are respectively close to the bipolar current collector.
  • the polarities of the outermost pole pieces of the polar current collectors are different.
  • one side of the bipolar current collector is electrically connected to the outermost positive electrode sheet of the electrode assembly adjacent thereto, and the other side of the bipolar current collector is electrically connected to the outermost positive electrode sheet of the electrode assembly adjacent thereto.
  • the outermost negative electrode pieces of the adjacent electrode assemblies are electrically connected.
  • the bipolar current collector is connected to the outer package, and independent sealed cavities are formed on both sides of the bipolar current collector, and each sealed cavity contains an electrode assembly and Electrolyte.
  • the electrolyte includes an organic solvent.
  • the bipolar current collector further includes a sealing area, the sealing area is sealed with the outer package, the sealing area contains a sealing material, and the sealing material has a melting point of 100° C. to 200° C. °C.
  • the material of the bipolar current collector includes at least one of Cu-Al composite current collector, stainless steel foil current collector or polymer conductive current collector;
  • the sealing material includes at least one of polypropylene (PP), polyester or p-hydroxybenzaldehyde (PHBA).
  • PP polypropylene
  • PHBA p-hydroxybenzaldehyde
  • the Z-direction of the bipolar current collector electronic resistivity of 1 ⁇ 10 - 11 ⁇ ⁇ cm to 30 ⁇ ⁇ cm.
  • the bipolar current collector has a water permeability M ⁇ 10 ⁇ 3 g/(day ⁇ m 2 ⁇ Pa ⁇ 3mm).
  • the bipolar current collector has a thickness of 2 ⁇ m to 100 ⁇ m.
  • the seal thickness T and the seal width W satisfy T/W ⁇ 0.05, where the units of T and W are mm.
  • the electrochemical device has at least one of the following features:
  • the electrochemical device comprises 2 to 3 bipolar current collectors
  • the melting point of the sealing material is 110°C to 180°C;
  • the electron resistivity in the Z direction of the bipolar current collector is 1 ⁇ 10 ⁇ 5 ⁇ cm to 5 ⁇ cm;
  • the thickness of the bipolar current collector is 5 ⁇ m to 50 ⁇ m;
  • the seal thickness T and the seal width W satisfy 0.02 ⁇ T/W ⁇ 0.04.
  • the electrochemical device has at least one of the following features:
  • the melting point of the sealing material is 120°C to 160°C;
  • the electronic resistivity in the Z direction of the bipolar current collector is 0.01 ⁇ cm to 0.10 ⁇ cm;
  • the thickness of the bipolar current collector is 5 ⁇ m to 20 ⁇ m.
  • the structure of the electrode assembly includes at least one of a wound structure or a laminated structure.
  • a second aspect of the present application provides an electronic device, including the electrochemical device provided in the first aspect of the present application.
  • the electrochemical device provided in this application divides the battery into a plurality of independent sealed cavities through the introduction of bipolar current collectors and the sealing design around the bipolar current collectors and the inner layer of the outer packaging, and between the plurality of electrode assemblies
  • the ionic insulation between the multi-electrode components of the liquid series battery is realized, and the safety hazard of internal short circuit or high-voltage decomposition of the electrolyte is avoided, thereby improving the safety performance of the electrochemical device and ensuring the effective power output of the high-voltage battery.
  • FIG. 1 is a schematic structural diagram of an electrochemical device according to an embodiment of the present application.
  • FIG. 2 is a schematic diagram of the exploded structure of the electrochemical device of FIG. 1 .
  • FIG. 3 is a schematic cross-sectional structure diagram of a series electrode assembly in an embodiment of the present application.
  • FIG. 4 is a front view of an electrochemical device according to an embodiment of the present application.
  • FIG. 5 is a top view of an electrochemical device according to an embodiment of the present application.
  • the electrochemical device described in the present application is not particularly limited, and can be any electrochemical device that can use the present application, such as lithium-ion batteries, sodium-ion batteries, magnesium-ion batteries, supercapacitors, and the like.
  • a lithium ion battery is used as an example for description, but this does not mean that the electrochemical device of the present application is limited to a lithium ion battery.
  • a first aspect of the present application provides an electrochemical device comprising a bipolar current collector and an electrode assembly, the electrode assemblies are located on both sides of the bipolar current collector, and the electrode assemblies on both sides are respectively close to the bipolar current collector.
  • the polarities of the outermost pole pieces of the polar current collector are different, one side of the bipolar current collector is electrically connected to the outermost positive pole piece of the electrode assembly adjacent to it, and the bipolar current collector has a different polarity.
  • the other side is electrically connected to the outermost negative electrode piece of the adjacent electrode assembly.
  • FIG. 2 shows an embodiment of the present application, wherein the electrode assemblies 30 are located on both sides of the bipolar current collector 10 , and the electrode assemblies 30 on both sides are respectively close to the outermost pole pieces of the bipolar current collector 10 .
  • one side of the bipolar current collector 10 is electrically connected to the outermost positive electrode piece of the electrode assembly 30 adjacent to it, and the other side of the bipolar current collector 10 is connected to the electrode assembly adjacent to it.
  • the outermost negative pole piece of 30 is electrically connected.
  • the above-mentioned “electrical connection” includes that the current collector of the positive electrode sheet or the negative electrode sheet is in physical contact with one side of the bipolar current collector, or through physical contact with one side of the bipolar current collector.
  • the circuit connection is realized by contacting the conductive sheet, that is, there is no electrode active material on the surface of the electrode sheet electrically connected with the bipolar current collector.
  • the specific number of bipolar current collectors included in the electrochemical device is not limited, and those skilled in the art can select according to actual needs, as long as the purpose of the present application can be achieved, for example, 2 to 3 of the bipolar current collectors are included. Electrode assemblies are provided on both sides of the bipolar current collector.
  • the bipolar current collector is hermetically connected to the outer package, and independent sealed cavities are formed on both sides of the bipolar current collector, and each sealed cavity encapsulates an electrode assembly and electrolyte.
  • FIG. 1 shows an embodiment of the present application, the bipolar current collector 10 is sealingly connected with the outer package 20 , and independent sealing cavities are formed on both sides of the bipolar current collector 10 , and each sealing cavity is The body contains an electrode assembly 30 and electrolyte.
  • the above-mentioned “outer packaging” usually refers to an aluminum-plastic film
  • the aluminum-plastic film includes a nylon layer, an aluminum foil layer and a PP layer
  • the thickness of the aluminum-plastic film can be 60 ⁇ m to 500 ⁇ m, preferably 60 ⁇ m to 300 ⁇ m , more preferably 60 ⁇ m to 200 ⁇ m.
  • the separator is not particularly limited, as long as the purpose of the present application can be achieved, any separator known in the art may be used.
  • any separator known in the art may be used.
  • PET polyethylene terephthalate
  • PET polyethylene terephthalate
  • PI polyimide Amine film
  • PA polyamide film
  • aramid film woven film, non-woven film (non-woven fabric), microporous film, composite film, diaphragm paper, rolled film, spinning film, etc. at least one of.
  • 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 polyethylene, polypropylene, polyethylene terephthalate, polyimide, and the like. A sort of.
  • 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, etc.
  • 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) and the like.
  • the positive electrode sheet is not particularly limited, as long as the purpose of the present application 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 known in the art, for example, can include NCM811, NCM622, NCM523, NCM111, NCA, lithium iron phosphate, lithium cobaltate, lithium manganate, lithium iron manganese phosphate Or at least one of lithium titanate and the like.
  • the positive electrode sheet may further comprise a conductive layer located between the positive electrode current collector and the positive electrode active material.
  • the composition of the conductive layer is not particularly limited, and may be a conductive layer commonly used in the art.
  • the conductive layer includes a conductive agent and an adhesive.
  • the negative pole piece is not particularly limited, as long as the purpose of the present application can be achieved.
  • the negative electrode sheet generally includes a negative electrode current collector and a negative electrode active material.
  • the negative electrode current collector is not particularly limited, and can be any negative electrode current collector known in the art, such as copper foil, copper alloy foil, or composite current collector.
  • the negative electrode active material is not particularly limited, and may be any negative electrode active material known in the art. For example, at least one of graphite, hard carbon, soft carbon, silicon, silicon carbon, silicon oxide, and the like may be included.
  • the above-mentioned conductive agent is not particularly limited, and any conductive agent known in the art can be used as long as the purpose of the present application can be achieved.
  • the conductive agent may include at least one of conductive carbon black (Super P), carbon nanotubes (CNTs), carbon fiber or graphene, and the like.
  • conductive carbon black (Super P) can be selected as the conductive agent.
  • the above-mentioned adhesive is not particularly limited, and any adhesive known in the art can be used as long as the purpose of the present application can be achieved.
  • the adhesive may include at least one of styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC-Na), and the like.
  • SBR styrene-butadiene rubber
  • PVA polyvinyl alcohol
  • PTFE polytetrafluoroethylene
  • CMC-Na sodium carboxymethyl cellulose
  • SBR styrene-butadiene rubber
  • the electrolyte is not particularly limited, and an electrolyte known to those skilled in the art can be used, for example, the electrolyte is selected from any one of gel state, solid state and liquid state.
  • the liquid electrolyte includes a lithium salt and a 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 purpose of the present application can be achieved.
  • lithium salts may include LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB(C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2 , LiC(SO 2 ) At least one of CF 3 ) 3 or LiPO 2 F 2 and the like.
  • LiPF 6 can be selected as the lithium salt.
  • the non-aqueous solvent is not particularly limited as long as the purpose of the present application can be achieved.
  • the non-aqueous solvent may include at least one of carbonate compounds, carboxylate compounds, ether compounds, nitrile compounds, other organic solvents, and the like.
  • the carbonate compound may include diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate Ester (MEC), Ethylene Carbonate (EC), Propylene Carbonate (PC), Butylene Carbonate (BC), Vinyl Ethylene Carbonate (VEC), Fluoroethylene Carbonate (FEC), Carbonic Acid 1 ,2-difluoroethylene, 101,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate, carbonic acid 1-Fluoro-2-methylethylene, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2-trifluorocarbonate -At least one of 2-methylethylene, trifluoromethylethylene carbonate, and the like.
  • DEC diethyl carbonate
  • the bipolar current collector is hermetically connected to the outer package, and the adjacent electrode assemblies and the electrolyte are completely separated by the bipolar current collector, so that each is in an independent sealed cavity, and different Ionic isolation is achieved between the cavities.
  • Both sides of the same bipolar current collector are respectively electrically connected to adjacent electrode assemblies, wherein one side of the bipolar current collector is electrically connected to the outermost positive pole piece of the electrode assembly adjacent to it, and the positive pole piece is electrically connected.
  • There is no electrode active material on one side of the electrical connection; the other side of the bipolar current collector is electrically connected with the outermost negative pole piece of the adjacent electrode assembly, and the side of the negative pole piece that is electrically connected has no electrode activity Material.
  • FIG. 3 is a schematic cross-sectional structure diagram of an electrode assembly in series in an embodiment of the present application.
  • the lower side of the bipolar current collector 10 is the first electrode assembly 31
  • the upper side is the second electrode assembly 32
  • the two are
  • Each electrode assembly includes a positive electrode current collector 61 , a positive electrode active material 71 , a negative electrode current collector 62 , a negative electrode active material 72 and a separator 80 .
  • the bipolar current collector 10 is placed on the first electrode assembly 31 , and one side of the bipolar current collector 10 is connected to the first electrode
  • the negative electrode current collector 62 of the uppermost layer of the assembly 31 is electrically connected, and the side of the negative electrode current collector 62 connected to the bipolar current collector 10 has no negative electrode active material 72;
  • the second electrode assembly 32 is placed on the bipolar current collector 10, and its most
  • the cathode current collector 61 of the lower layer is electrically connected to the other side of the bipolar current collector 10 , and the side of the cathode current collector 61 connected to the bipolar current collector 10 has no cathode active material 71 .
  • the design of the above-mentioned internal series structure avoids the need to lead out and weld the tabs of multiple electrode assemblies to achieve series connection, thereby simplifying the process and improving the production efficiency, and solving the problem of poor series connection of the electrode assemblies caused by welding, which greatly improves the performance.
  • the manufacturing reliability of the battery is beneficial to the output of electric energy, and the reduction of the number of tabs effectively improves the energy density of the high-output voltage battery.
  • the bipolar current collector further includes a sealing area, the sealing area is sealingly connected to the outer package, the sealing area further includes a sealing material, and the sealing material includes polypropylene (PP) At least one of , polyester or p-hydroxybenzaldehyde (PHBA), the melting point of the sealing material is 100 to 200°C, preferably 110 to 180°C, more preferably 120 to 160°C.
  • PP polypropylene
  • PHBA p-hydroxybenzaldehyde
  • the above-mentioned outer contour sealing area is hermetically connected to the outer package, specifically, a fusible sealing material is compounded around the bipolar current collector, and is heat-sealed and sealed with the inner layer of the outer package at a temperature of 100 to 200 ° C, thereby
  • the electrochemical device is formed with independent sealed cavities, so that the ionic insulation between the multi-electrode components of the liquid series battery is realized between the plurality of electrode components, the safety hazard of internal short circuit or high-voltage decomposition of the electrolyte is avoided, and the electrochemical performance is improved. safety performance of the device.
  • the material of the bipolar current collector includes at least one of a Cu-Al composite current collector, a stainless steel foil current collector or a polymer conductive current collector.
  • the bipolar current collector has good electrical conductivity in the thickness direction (hereinafter referred to as the Z direction), for example, the electronic resistivity of the bipolar current collector in the Z direction is 1 ⁇ 10 ⁇ 11 to 30 ⁇ cm , preferably 1 ⁇ 10 ⁇ 5 to 5 ⁇ cm, more preferably 0.01 to 0.10 ⁇ cm.
  • the polymer conductive current collector includes a composite material composed of a polymer material and a conductive material.
  • the application does not specifically limit the polymer conductive current collector as long as the object of the present invention can be achieved.
  • a polymer conductive current collector includes A polymer matrix and a conductive agent, wherein the conductive agent is a one-dimensional or two-dimensional conductive material, and the conductive material is distributed in the polymer matrix at an angle of 0° to 30° with the thickness direction of the polymer matrix.
  • Another polymer conductive current collector includes conductive layers respectively arranged on two surfaces of the polymer matrix, and the two conductive layers are electrically connected.
  • Another polymer conductive current collector includes a porous polymer matrix, and the conductive material is located in the pores of the porous polymer matrix, so that the two surfaces of the polymer conductive current collector can achieve electronic conduction.
  • the preparation method of the polymer conductive current collector in this application there is no particular limitation on the preparation method of the polymer conductive current collector in this application, as long as the object of the present invention can be achieved, for example, it can be obtained by the following method: spraying a polymer material on a stainless steel substrate to obtain a polymer material layer, heating the polymer material Then, the one-dimensional or two-dimensional conductive material is implanted, and then the polymer material is sprayed again to form a polymer material film, and the obtained polymer material film is superheated and rolled. Next, roll up to obtain a polymer conductive current collector.
  • the polymer film includes polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polyether ether ketone, polyimide, polyamide, Polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polynaphthalene Ethylene formate, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), silicone resin, vinylon, polypropylene, polyethylene , polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polysulfone or at least one of the derivatives of the above substances.
  • PET polyethylene
  • the conductive material includes at least one of carbon material or metal material.
  • the carbon material may include at least one of single-walled carbon nanotubes, multi-walled carbon nanotubes (MWCNTs), conductive carbon fibers, conductive carbon black, fullerenes, conductive graphite or graphene.
  • MWCNTs multi-walled carbon nanotubes
  • conductive carbon fibers conductive carbon black
  • fullerenes conductive graphite or graphene.
  • the metal material may include at least one of Cu, Al, Ni, Ti, Ag, Au, Pt or stainless steel and alloys thereof.
  • the polymer conductive current collector can also be formed by other methods.
  • conductive agent particles and the like are dispersed in a polymer material.
  • the bipolar current collector has a water permeability M ⁇ 10 ⁇ 3 g/(day ⁇ m 2 ⁇ Pa ⁇ 3 mm), preferably M ⁇ 10 ⁇ 4 g/(day ⁇ m 2 ⁇ Pa ⁇ 3mm), so as to prevent the lithium-ion battery from exceeding the standard water content during the service life of the lithium-ion battery after packaging.
  • the bipolar current collector has a thickness of 2 ⁇ m to 100 ⁇ m, preferably 5 ⁇ m to 50 ⁇ m, and more preferably 5 to 20 ⁇ m.
  • the thickness of the bipolar current collector is less than 2 ⁇ m, the mechanical strength of the bipolar current collector may be insufficient; when its thickness is greater than 100 ⁇ m, the mass of the introduced inactive material increases, reducing the energy density of the lithium-ion battery.
  • the seal thickness T and the seal width W satisfy T/W ⁇ 0.05, preferably 0.02 ⁇ T/W ⁇ 0.04.
  • the "seal” refers to the sealed area of the outer package.
  • FIG. 4 is a front view of an embodiment of the application, the thickness T of the sealing area 40 of the outer package is the sealing thickness T;
  • FIG. 5 is a top view of an embodiment of the application, the width W of the sealing area 40 of the outer packaging That is, the seal width W.
  • T/W ⁇ 0.05 excellent packaging reliability can be achieved, otherwise, the packaging effect will be reduced due to inappropriate seal thickness and seal width.
  • the sealing width and the sealing thickness are not particularly limited, as long as the ratio meets the requirements, and those skilled in the art can select according to the specific battery size, for example, the sealing width is preferably 1 mm to 7 mm.
  • the type of the electrode assembly is not particularly limited, for example, it may include at least one of a wound structure or a laminated structure.
  • the structure of the electrode assembly includes a winding structure, and the electrode assembly draws out at least one positive electrode tab and one negative electrode tab from the positive electrode tab and the negative electrode tab, respectively.
  • the structure of the electrode assembly is a laminated structure, and the electrode assembly includes a plurality of tabs, which may be one positive tab and one negative electrode drawn from each layer of positive electrode and negative electrode respectively. Tabs, and finally a laminated structure electrode assembly includes multiple sets of positive tabs and negative tabs, and then lead out metal sheets through transfer welding and turning tabs.
  • the welding method of the tab is not particularly limited, as long as the purpose of the present application can be achieved.
  • the bipolar current collector may or may not be drawn out of the tab, and when the bipolar current collector is drawn out of the tab, it can be used to monitor the voltage of a single electrode assembly.
  • the direction in which the tabs are drawn out is not particularly limited, as long as the purpose of the present application can be achieved.
  • the lead-out directions of the tabs can be the same direction or different directions.
  • a second aspect of the present application provides an electronic device comprising the electrochemical device provided in the first aspect of the present application.
  • the electronic devices described in this application include general electronic devices in the art, such as notebook computers, mobile phones, electric motorcycles, electric vehicles, electric toys, energy storage systems, drones, power tools, cleaning robots, tablet computers, power grids, Electric boat etc.
  • the test temperature was 25 ⁇ 3°C
  • the lithium-ion battery was charged to 4.2V with a constant current of 0.5C, and then charged to a current of 0.05C with a constant voltage of 4.2V, and left for 1 hour to measure open circuit voltage.
  • the test temperature was 25 ⁇ 3°C, and the lithium-ion battery was charged to 8.4V with a constant current of 0.5C, and then charged to a current of 0.05 with a constant voltage of 8.4V. C, stand for 1 hour, and measure the open circuit voltage.
  • the test temperature was 25 ⁇ 3°C
  • the lithium-ion battery was charged to 4.2V with a constant current of 0.5C, then charged to a current of 0.05C with a constant voltage of 4.2V, left for 10 minutes, and then discharged with a current of 0.5C
  • the test temperature was 25 ⁇ 3°C
  • the bipolar current collector with a certain thickness is placed on the clamping mechanism, and the edge is pressed by the large pressure of rubber.
  • a fixed temperature and humidity environment is created on one side A of the device, and a water vapor mass spectrometer detection probe is placed on the other side B, and the gas exchange on both sides can only pass through bipolar current collectors.
  • the bipolar current collector is fixed first, and the cavity B is evacuated to discharge the internal water vapor. Then, the mass spectrometer is turned on, and the mass spectrometer continuously receives the water vapor permeating from the cavity A and converts it into an electrical signal for output.
  • the negative electrode active material graphite (Graphite), conductive carbon black (Super P), and styrene-butadiene rubber (SBR) were mixed in a weight ratio of 96:1.5:2.5, and then deionized water was added as a solvent to prepare a solid content of 70%. slurry and mix well.
  • the slurry was uniformly coated on one surface of the negative current collector copper foil with a thickness of 8 ⁇ m, and dried at 110° C. to obtain a negative electrode sheet with a coating thickness of 130 ⁇ m coated with negative active material on one side.
  • the single-side coating of the negative pole piece has been completed.
  • the above steps are repeated on the other surface of the negative electrode pole piece to obtain a negative electrode pole piece coated with negative electrode active material on both sides.
  • the pole piece is cut into a size of 41mm ⁇ 61mm for use.
  • the polymer conductive current collector composed of PET and MWCNT is selected as the bipolar current collector, wherein the thickness of the polymer conductive current collector is 100 ⁇ m, the electronic resistivity in the Z direction is 0.06 ⁇ cm, and the water permeability is 5 ⁇ 10 -5 g/(day ⁇ m 2 ⁇ Pa ⁇ 3mm), the bipolar current collector is provided with a sealing layer around the periphery, wherein T/W is 0.025.
  • electrode assembly A Place a piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) formed by punching in the assembly jig, with the pit facing up, and place an electrode assembly (hereinafter referred to as electrode assembly A) in the pit, the top layer of which is the negative electrode. There is no negative active material on the upper surface of the negative electrode. Pull out the positive tab of electrode assembly A.
  • Electrolyte is injected separately into the two cavities of the assembled electrode assembly, and sealed after injection.
  • the charging and discharging process only needs to connect the positive electrode tab of electrode assembly A and the negative electrode tab of electrode assembly B.
  • sealing material shown in Table 1 is p-hydroxybenzaldehyde (PHBA), and the melting point of the sealing material is 115° C., the rest is the same as that of Example 2.
  • PHBA p-hydroxybenzaldehyde
  • Example 1 Except that the preparation process of the lithium ion battery is different from that of Example 1, the rest is the same as that of Example 1.
  • Example 1 Except that the preparation process of the lithium ion battery is different from that of Example 1, the rest is the same as that of Example 1.
  • the polymer conductive current collector composed of PET and MWCNT is selected as the bipolar current collector, wherein the thickness of the polymer conductive current collector is 15 ⁇ m, the electronic resistivity in the Z direction is 0.06 ⁇ cm, and the water permeability is 5 ⁇ 10 -5 g/(day ⁇ m 2 ⁇ Pa ⁇ 3mm), a sealing layer is provided at the periphery of the bipolar current collector, wherein T/W is 0.025, and the tabs of the bipolar current collector are drawn out.
  • a piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) formed by punching is placed in the assembly jig with the pit surface facing up, and then an electrode assembly (hereinafter referred to as electrode assembly A) is placed in the pit, and its top layer is the negative electrode.
  • electrode assembly A an electrode assembly
  • a pole piece, the upper surface of the negative pole piece has no negative electrode active material.
  • a plurality of positive electrode tab lead-out pieces of the electrode assembly A are welded into one positive electrode tab by transfer welding, and the positive electrode tab is drawn out.
  • Electrode assembly B An electrode assembly (hereinafter referred to as electrode assembly B) is placed on the bipolar current collector, and its positive electrode plate is in contact with the bipolar current collector, and the lower surface of the positive electrode plate has no positive electrode active material, and is pressed by an external force. Then, cover another piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) on the electrode assembly B with the pit face down, and weld the multiple negative electrode tab lead-out pieces of the electrode assembly B into a negative electrode tab by transfer welding. , the negative electrode tab is drawn out, and other positions of the outer packaging are heat-sealed after the liquid injection port side is left to obtain an assembled electrode assembly, wherein two independent cavities are formed on both sides of the bipolar current collector. Among them, the heat-sealing temperature was 180°C, and the heat-sealing pressure was 0.5MPa.
  • Electrolyte is injected separately into the two cavities of the assembled electrode assembly, and sealed after injection.
  • the charging and discharging process only needs to connect the positive electrode tab of electrode assembly A and the negative electrode tab of electrode assembly B.
  • Example 1 Except that the preparation process of the lithium ion battery is different from that of Example 1, the rest is the same as that of Example 1.
  • the polymer conductive current collector composed of PET and MWCNT is selected as the bipolar current collector, wherein the thickness of the polymer conductive current collector is 15 ⁇ m, the electronic resistivity in the Z direction is 0.06 ⁇ cm, and the water permeability is 5 ⁇ 10 - 5 g/(day ⁇ m 2 ⁇ Pa ⁇ 3mm), a sealing layer is provided on the periphery of the bipolar current collector, wherein T/W is 0.025, and the tabs of the bipolar current collector are drawn out.
  • a piece of outer packaging (aluminum-plastic film with a thickness of 200 ⁇ m) formed by punching is placed in the assembly jig with the pit surface facing up, and then an electrode assembly (hereinafter referred to as electrode assembly A) is placed in the pit, and its top layer is the negative electrode.
  • electrode assembly A an electrode assembly
  • a pole piece, the upper surface of the negative pole piece has no negative electrode active material. Pull out the positive tab of electrode assembly A.
  • bipolar current collector A a bipolar current collector (hereinafter referred to as bipolar current collector A) is placed on the electrode assembly A, so that it is in contact with the negative pole piece of the electrode assembly A, and is pressed by an external force.
  • electrode assembly C An electrode assembly (hereinafter referred to as electrode assembly C) is placed on the bipolar current collector A, so that the positive electrode piece is in contact with the bipolar current collector A, and there is no positive active material on the lower surface of the positive electrode piece, and an external force is applied to press it. .
  • bipolar current collector B a bipolar current collector (hereinafter referred to as bipolar current collector B) is placed on the electrode assembly C, so that the bipolar current collector B is in contact with the negative pole piece of the electrode assembly C, and an external force is applied to press the negative electrode. There is no negative active material on the upper surface of the pole piece.
  • Electrode assembly B An electrode assembly (hereinafter referred to as electrode assembly B) is placed on the bipolar current collector B, so that the positive electrode piece is in contact with the bipolar current collector B, and the lower surface of the positive electrode plate has no positive active material, and is pressed by external force . Then, cover another piece of outer packaging (aluminum-plastic film with a thickness of 200 ⁇ m) on the electrode assembly B with the pit face down, and pull out the negative electrode tab of the electrode assembly B, leaving the liquid injection port side and heat sealing the outer packaging. In other positions, an assembled electrode assembly is obtained, wherein three independent cavities are formed on both sides of the bipolar current collectors A and B. Among them, the heat-sealing temperature was 180°C, and the heat-sealing pressure was 0.5MPa.
  • Electrolyte is separately injected into the three cavities of the assembled electrode assembly, and sealed after injection.
  • the charging and discharging process only needs to connect the positive electrode tab of electrode assembly A and the negative electrode tab of electrode assembly B.
  • the polymer conductive current collector composed of PET and graphene is selected as the bipolar current collector, and the electronic resistivity of the bipolar current collector in the Z direction shown in Table 1 is 0.1 ⁇ cm, the rest are the same as those in the examples. 2 are the same.
  • Example 1 Except that the positive pole piece was cut into a size of 480 mm ⁇ 90 mm for use, the rest was the same as that of Example 1.
  • the positive pole piece and the negative pole piece prepared above, and the PP separator of 15 ⁇ m are stacked in the order of the positive pole piece, the separator and the negative pole piece, so that the separator is in the middle of the positive pole piece and the negative pole piece to isolate the Acting, winding to obtain a wound electrode assembly.
  • a piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) formed by punching was placed in the assembly jig with the pit facing upward, and an electrode assembly (hereinafter referred to as electrode assembly A) was placed in the pit. Then, cover another piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) on the electrode assembly A with the pit face down, and pull out the positive and negative electrodes of the electrode assembly A, leaving the liquid injection port side and heat-sealing the outside. Elsewhere in the package, get the assembled electrode assembly. Among them, the heat-sealing temperature was 180°C, and the heat-sealing pressure was 0.5MPa.
  • the charging and discharging process only needs to connect the positive electrode tab and the negative electrode tab of the electrode assembly A.
  • electrode assembly A Place a piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) formed by punching in the assembly jig, with the pit facing up, and place an electrode assembly (hereinafter referred to as electrode assembly A) in the pit, the top layer of which is the negative electrode. There is no negative active material on the upper surface of the negative electrode. Pull out the positive tab of electrode assembly A.
  • Electrolyte is injected into the assembled electrode assembly and sealed after injection.
  • the charging and discharging process only needs to connect the positive electrode tab of electrode assembly A and the negative electrode tab of electrode assembly B.
  • electrode assembly A Place a piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) formed by punching in the assembly jig, with the surface of the pit facing up, and then place an electrode assembly (hereinafter referred to as electrode assembly A) in the pit, the uppermost layer of which is the diaphragm. . Pull out the positive and negative tabs of electrode assembly A.
  • Electrode assembly B An electrode assembly (hereinafter referred to as electrode assembly B) is placed on the electrode assembly A, so that the separator of the electrode assembly B is in contact with the separator side of the electrode assembly A, and the positive electrode plate is above the separator, and is pressed by an external force. Then, cover another piece of outer packaging (aluminum-plastic film with a thickness of 150 ⁇ m) on the electrode assembly B with the pit face down, and pull out the positive and negative electrodes of the electrode assembly B. Elsewhere in the package, get the assembled electrode assembly. Among them, the heat-sealing temperature was 180°C, and the heat-sealing pressure was 0.5MPa.
  • Electrolyte is injected into the assembled electrode assembly and sealed after injection.
  • the negative electrode tab of electrode assembly A and the positive electrode tab of electrode assembly B are welded together by laser welding, so that electrode assemblies A and B are connected in series.
  • the charging and discharging process only needs to connect the positive electrode tab of electrode assembly A and the negative electrode tab of electrode assembly B.
  • Examples 1-25 and Comparative Examples 1-3 of the present application that the electrochemical devices (for example, Examples 1-25) connected in series with bipolar current collectors have higher output voltages, and electrical After 50 charge-discharge cycles of the chemical device, the discharge capacity/first discharge capacity of Examples 1-25 of the present application was significantly improved.
  • the electrode assemblies are connected in series through the bipolar current collector, and the bipolar current collector is sealed with the outer packaging, so that the battery is divided into a plurality of independent sealed cavities, and between the plurality of electrode assemblies
  • the ion isolation between the multi-electrode components of the liquid series battery is realized, and the safety hazard of internal short circuit or high-voltage decomposition of the electrolyte is avoided, thereby improving the safety performance of the electrochemical device and ensuring the effective power output of the high-voltage battery.
  • the internal series connection of electrode assemblies is realized, so that there is no need to realize the structural design of series connection by welding the tabs between multiple electrode assemblies, which can simplify the process and improve the production.
  • the problem of poor connection of electrochemical devices caused by welding is avoided, the manufacturing reliability of the electrochemical devices is greatly improved, and the output of electric energy is beneficial.
  • the reduction in the number of tabs effectively improves the energy density of high output voltage batteries to a certain extent.

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Abstract

一种电化学装置及包含该电化学装置的电子装置。上述电化学装置包含至少一个双极性集流体(10)，所述双极性集流体(10)与外包装(20)密封连接，在所述双极性集流体(10)两侧形成各自独立的密封腔体，每个密封腔体中包含一个电极组件(30)和电解液，所述双极性集流体(10)的一侧与相邻的电极组件(30)的最外层正极极片电连接，所述双极性集流体(10)的另一侧与相邻的电极组件(30)的最外层负极极片电连接。通过双极性集流体(10)的引入以及双极性集流体(10)与外包装(20)内层的密封设计，使多个电极组件(30)之间实现液态串联电池多电极组件(30)间的离子绝缘，从而实现了高输出电压电池使用的可靠性和电能的有效输出。

Description

一种电化学装置及包含该电化学装置的电子装置 技术领域
本申请涉及电化学领域，具体涉及一种电化学装置及包含该电化学装置的电子装置。
背景技术
锂离子电池具有能量密度大、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(EV)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。
在现有锂离子电池体系中，受限于电化学体系的限制，如正负极材料的电压差有限、电解液抗氧化还原能力有限等，锂离子电池的工作电压很难超过5V。但实际使用中，需要用到超过5V电压的场景很多，比如电动汽车(EV)、电压互感器(PT)、储能系统(ESS)等。即使在手机市场，为了满足快充等需求，也需要锂离子电池开路电压的提升。
目前一些公司提出了串联电池的概念来解决这一问题，其方案是直接在同一个包装袋内串联两个锂离子电池，但通常存在如下问题：一方面，其未对两串联锂离子电池做离子绝缘，该情况下因电池电压升高，电解液在高电压条件下分解，将导致电池失效，同时两个锂离子电池间会因极片电压差发生内短路，电池也会失效；另一方面，该串联方式需要将不同锂离子电池的不同极性极耳焊接以实现锂离子电池的串联，而极耳焊接效果不佳易导致锂离子电池内阻增大等问题，不但存在极大的安全隐患而且不利于电能的输出，同时，多个极耳引出片的设计，会增加极耳的断裂风险，从而降低生产优率。因此，开发一种新的串联结构的锂离子电池，实现高输出电压电池使用可靠性和电能的有效输出，成为本领域技术人员亟待解决的问题。
发明内容
本申请提供了一种电化学装置及包含该电化学装置的电子装置，以实现高输出电压电池使用可靠性和电能的有效输出。
本申请第一方面提供了一种电化学装置，其包含双极性集流体与电极组件，所述电极组件位于所述双极性集流体的两侧，且两侧电极组件各自靠近所述双极性集流体的最外层极片的极性不同。
在本申请的一些实施方式中，所述双极性集流体的一侧和与其相邻的电极组件的最外层正极极片电连接，所述双极性集流体的另一侧和与其相邻的电极组件的最外层负极极片电连接。
在本申请的一些实施方式中，所述双极性集流体与外包装连接，在所述双极性集流体两侧形成各自独立的密封腔体，每个密封腔体中包含一个电极组件和电解液。
在本申请的一些实施方式中，所述电解液包括有机溶剂。
在本申请的一些实施方式中，所述双极性集流体还包括密封区域，所述密封区域与外包装密封连接，所述密封区域包含密封材料，所述密封材料的熔点为100℃至200℃。
在本申请的一些实施方式中，所述双极性集流体的材料包括Cu-Al复合集流体、不锈钢箔集流体或高分子导电集流体中的至少一种；
所述密封材料包括聚丙烯(PP)、聚酯或对羟基苯甲醛(PHBA)中的至少一种。
在本申请的一些实施方式中，所述双极性集流体的Z方向的电子电阻率为1×10 - 11Ω·cm至30Ω·cm。
在本申请的一些实施方式中，所述双极性集流体渗水率M≤10 -3g/(day·m 2·Pa·3mm)。
在本申请的一些实施方式中，所述双极性集流体厚度为2μm至100μm。
在本申请的一些实施方式中，所述双极性集流体与所述外包装连接处，封印厚度T与封印宽度W满足T/W≤0.05，其中，T和W的单位为mm。
在本申请的一些实施方式中，所述电化学装置具有以下特征中的至少一个：
a.所述电化学装置包含2至3个双极性集流体；
b.所述密封材料的熔点为110℃至180℃；
c.所述双极性集流体的Z方向的电子电阻率为1×10 -5Ω·cm至5Ω·cm；
d.所述双极性集流体渗水率M≤10 -4g/(day·m 2·Pa·3mm)；
e.所述双极性集流体厚度为5μm至50μm；
f.所述封印厚度T与所述封印宽度W满足0.02≤T/W≤0.04。
在本申请的一些实施方式中，所述电化学装置具有以下特征中的至少一个：
1).所述密封材料的熔点为120℃至160℃；
2).所述双极性集流体的Z方向的电子电阻率为0.01Ω·cm至0.10Ω·cm；
3).所述双极性集流体厚度为5μm至20μm。
在本申请的一些实施方式中，所述电极组件的结构包括卷绕结构或叠片结构中的至少一种。
本申请第二方面提供了一种电子装置，包含本申请第一方面所提供的电化学装置。
本申请提供的电化学装置，通过双极性集流体的引入以及双极性集流体四周与外包装内层的密封设计，将电池分割为多个独立的密封腔体，多个电极组件之间实现液态串联电池多电极组件间的离子绝缘，避免发生内短路或电解液高压分解的安全隐患，从而提高电化学装置的安全性能，保证了高电压电池有效的电能输出。此外，通过不同电极组件结构和双极性集流体的设计，实现电极组件的内部串联，无需通过多个电极组件间极耳的焊接实现串联的结构设计，简化工序、提高生产效率的同时，避免焊接带来的电化学装置串联的不良问题，大大提高电化学装置的制造可靠性，有利于电能的输出。另外，极耳数量的降低有效提高了高输出电压电池的能量密度。
附图说明
为了更清楚地说明本申请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申请的一些实施方式，对于本领域普通技术人员来讲，还可以根据这些附图获得其他的实施方式。
图1为本申请一种实施方式的电化学装置的结构示意图。
图2为图1的电化学装置分解结构示意图。
图3为本申请一种实施方式中串联电极组件的截面结构示意图。
图4为本申请一种实施方式的电化学装置主视图。
图5为本申请一种实施方式的电化学装置俯视图。
具体实施方式
为使本申请的目的、技术方案及优点更加清楚明白，以下参照附图和实施例，对本申请进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，所获得的所有其他实施例，都属于本申请保护的范围。
本申请中所述电化学装置没有特别限制，可以是能够使用本申请的任何电化学装置，例如锂离子电池、钠离子电池、镁离子电池、超级电容器等。为了方便描述，以下以锂离子电池为例进行描述，但这并不意味着本申请的电化学装置仅限于锂离子电池。
本申请第一方面提供了一种电化学装置，其包含双极性集流体与电极组件，所述电极组件位于所述双极性集流体的两侧，且两侧电极组件各自靠近所述双极性集流体的最外层极片的极性不同，所述双极性集流体的一侧和与其相邻的电极组件的最外层正极极片电连接，所述双极性集流体的另一侧和与其相邻的电极组件的最外层负极极片电连接。
图2示出了本申请的一种实施方式，其中，电极组件30位于双极性集流体10的两侧，且两侧电极组件30各自靠近双极性集流体10的最外层极片的极性不同，双极性集流体10的一侧和与其相邻的电极组件30的最外层正极极片电连接，所述双极性集流体10的另一侧和与其相邻的电极组件30的最外层负极极片电连接。
在本申请中，上述“电连接”包括，所述正极极片或负极极片的集流体分别通过与双极性集流体的一侧物理接触、或通过与双极性集流体的一侧物理接触导电片实现电路连接，即与双极性集流体电连接的电极极片表面没有电极活性物质。
在本申请的一些实施方式中，所述电化学装置包含的双极性集流体，具体数目不做限定，本领域技术人员可以根据实际需要进行选择，只要能实现本申请目的即可，例如，包含2至3个所述双极性集流体。所述双极性集流体两侧设有电极组件。
在本申请的一些实施方式中，所述双极性集流体与外包装密封连接，在所述双极性集流体两侧形成各自独立的密封腔体，每个密封腔体中封装一个电极组件和电解液。图1示出本申请的一种实施方式，所述双极性集流体10与外包装20密封连接，在所述双极性集流体10两侧形成各自独立的密封腔体，每个密封腔体中包含一个电极组件30和电解液。
在本申请中，上述的“外包装”通常是指铝塑膜，所述铝塑膜包含尼龙层、铝箔层 和PP层，所述铝塑膜厚度可以为60μm至500μm，优选为60μm至300μm，更优选为60μm至200μm。
在本申请的一些实施方式中，电极组件可以包含隔膜、正极极片和负极极片，所述隔膜用以分隔正极极片和负极极片，防止电化学装置内部短路，允许电解质离子自由通过，完成电化学充放电过程的作用。在本申请中，对隔膜、正极极片和负极极片的数量不做特别限定，只要能实现本申请目的即可。
在本申请的一些实施方式中，隔膜没有特别限制，只要能够实现本申请目的即可，可以使用本领域公知的任何隔膜。例如，聚乙烯(PE)、聚丙烯(PP)为主的聚烯烃(PO)类隔膜，聚酯膜(例如聚对苯二甲酸二乙酯(PET)膜)、纤维素膜、聚酰亚胺膜(PI)、聚酰胺膜(PA)，氨纶或芳纶膜、织造膜、非织造膜(无纺布)、微孔膜、复合膜、隔膜纸、碾压膜、纺丝膜等中的至少一种。
所述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等中的至少一种。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、氢氧化钙和硫酸钡等中的至少一种。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等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)等中的至少一种。
在本申请的一些实施方式中，正极极片没有特别限制，只要能够实现本申请目的即可。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，可以为本领域公知的任何正极活性材料，例如，可以包括NCM811、NCM622、NCM523、NCM111、NCA、磷酸铁锂、钴酸锂、锰酸锂、磷酸锰铁锂或钛酸锂等中的至少一种。
任选地，所述正极极片还可以包含导电层，所述导电层位于正极集流体和正极活性材料之间。所述导电层的组成没有特别限制，可以是本领域常用的导电层。例如，所述导电层包括导电剂和粘接剂。
在本申请的一些实施方式中，负极极片没有特别限制，只要能够实现本申请目的即可。例如，所述负极极片通常包含负极集流体和负极活性材料。其中，所述负极集流体没有特别限制，可以为本领域公知的任何负极集流体，例如铜箔、铜合金箔或复合集流体等。所述负极活性材料没有特别限制，可以为本领域公知的任何负极活性材料。例如，可以包括石墨、硬碳、软碳、硅、硅碳或硅氧化物等中的至少一种。
任选地，所述负极极片还可以包含导电层，所述导电层位于负极集流体和负极活性材料之间。所述导电层的组成没有特别限制，可以是本领域常用的导电层。例如，所述导电层包括导电剂和粘接剂。
上述所述导电剂没有特别限制，可以使用本领域公知的任何导电剂，只要能实现本申请目的即可。例如，导电剂可以包括导电炭黑(Super P)、碳纳米管(CNTs)、碳纤维或石墨烯等中的至少一种。例如，导电剂可选用导电炭黑(Super P)。上述所述粘接剂没有特别限制，可以使用本领域公知的任何粘接剂，只要能实现本申请目的即可。例如，粘接剂可以包括丁苯橡胶(SBR)、聚乙烯醇(PVA)、聚四氟乙烯(PTFE)或羧甲基纤维素钠(CMC-Na)等中的至少一种。例如，粘接剂可选用丁苯橡胶(SBR)。
在本申请中，电解液没有特别限制，可以采用本领域技术人员公知的电解液，例如，所述电解液选自凝胶态、固态和液态中的任意一种。例如，所述液态电解液包括锂盐和非水溶剂。
所述锂盐没有特别限制，可以使用本领域公知的任何锂盐，只要能实现本申请的目的即可。例如，锂盐可以包括LiPF 6、LiBF 4、LiAsF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3或LiPO 2F 2等中的至少一种。例如，锂盐可选用LiPF 6。
所述非水溶剂没有特别限定，只要能实现本申请的目的即可。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等中的至少一种。
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、10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等中的至少一种。
在本申请的一些实施方式中，所述双极性集流体与外包装密封连接，相邻的电极组件和电解液被双极性集流体完全分隔，从而各自处于独立的密封腔体中，不同腔体之间实现离子隔绝。同一双极性集流体两侧分别与相邻电极组件电连接，其中，双极性集流体的一侧和与其相邻的电极组件的最外层正极极片电连接，所述正极极片进行电连接的一侧没有电极活性材料；双极性集流体的另一侧和与其相邻的电极组件的最外层负极极片电连接，所述负极极片进行电连接的一侧没有电极活性材料。
图3为本申请一种实施方式中串联电极组件的截面结构示意图，如图3所示，双极性集流体10的下侧为第一电极组件31、上侧为第二电极组件32，两个电极组件包含有正极集流体61、正极活性材料71、负极集流体62、负极活性材料72和隔膜80，双极性集流体10放置于第一电极组件31上，其一侧与第一电极组件31最上层的负极集流体62电连接，该负极集流体62连接双极性集流体10的一侧没有负极活性材料72；第二电极组件32放置于双极性集流体10上，其最下层的正极集流体61与双极性集流体10的另一侧电连接，该正极集流体61连接双极性集流体10的一侧没有正极活性材料71。
上述内部串联结构的设计，避免了通过多个电极组件的极耳引出并焊接实现串联，从而在简化工序、提高生产效率的同时，解决了焊接带来的电极组件串联不良的问题，大大提高了电池的制造可靠性，有利于电能的输出，并且极耳数量的减少有效提高了高输出电压电池的能量密度。
在本申请的一些实施方式中，所述双极性集流体还包括密封区域，所述密封区域与外包装密封连接，所述密封区域还包含密封材料，所述密封材料包括聚丙烯(PP)、聚酯或 对羟基苯甲醛(PHBA)中的至少一种，所述密封材料的熔点为100至200℃，优选为110至180℃，更优选为120至160℃。
上述的外轮廓密封区域与外包装密封连接，具体地，是双极性集流体的四周复合可融合的密封材料，与外包装的内层在100至200℃的温度下进行热封密封，从而使所述电化学装置中形成各自独立的密封腔体，使多个电极组件之间实现液态串联电池多电极组件间的离子绝缘，避免发生内短路或电解液高压分解的安全隐患，提高电化学装置的安全性能。
在本申请的一些实施方式中，所述双极性集流体的材料包括Cu-Al复合集流体、不锈钢箔集流体或高分子导电集流体中的至少一种。所述双极性集流体在厚度方向上(以下称Z方向上)具有良好的导电性，例如，所述双极性集流体在Z方向的电子电阻率为1×10 -11至30Ω·cm，优选为1×10 -5至5Ω·cm，更优选为0.01至0.10Ω·cm。
所述高分子导电集流体包括由高分子材料与导电材料的复合材料，本申请对于高分子导电集流体没有特别限制，只要能够实现本发明目的即可，例如，一种高分子导电集流体包括高分子基体和导电剂，所述导电剂为一维或二维导电材料，所述导电材料以与高分子基体厚度方向成0°至30°角的方向分布在所述高分子基体中。另一种高分子导电集流体包含分别设置在高分子基体两个表面上的导电层，两个导电层之间电连接。另一种高分子导电集流体包括一种多孔高分子基体，导电材料位于多孔高分子基体的孔隙中，使得高分子导电集流体的两个表面实现电子导通。
本申请对高分子导电集流体的制备方法没有特别限制，只要能实现本发明目的即可，例如，可以通过以下方法得到：在不锈钢基板上喷涂高分子材料得到高分子材料层，加热高分子材料层使其软化，再植入一维或二维导电材料，随后再次喷涂高分子材料形成高分子材料薄膜，过热辊压所得的高分子材料薄膜，用刮刀将高分子材料薄膜从不锈钢基板表面取下，收卷得到高分子导电集流体。
所述高分子薄膜包括聚对苯二甲酸亚乙酯(PET)、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)、有机硅树脂、维尼纶、聚丙烯、聚乙烯、聚氯乙烯、聚苯乙烯、聚醚腈、聚氨 酯、聚苯醚、聚砜或上述物质衍生物中的至少一种。
所述导电材料包括碳材料或金属材料中的至少一种。
其中，碳材料可以包括单壁碳纳米管、多壁碳纳米管(MWCNT)、导电碳纤维、导电炭黑、富勒烯、导电石墨或石墨烯中的至少一种。
其中，金属材料可以包括包括Cu、Al、Ni、Ti、Ag、Au、Pt或不锈钢及其合金中的至少一种。
所述高分子导电集流体也可以通过其他方法形成。例如，在高分子材料中分散导电剂颗粒等等。
在本申请的一些实施方式中，所述双极性集流体渗水率M≤10 -3g/(day·m 2·Pa·3mm)，优选M≤10 -4g/(day·m 2·Pa·3mm)，从而避免锂离子电池在封装后在锂离子电池使用寿命内水含量超标。
在本申请的一些实施方式中，所述双极性集流体厚度为2μm至100μm，优选为5μm至50μm，更优选为5至20μm。当双极性集流体的厚度小于2μm时，双极性集流体的机械强度可能不足；当其厚度大于100μm时，引入的非活性物质质量增大，降低锂离子电池的能量密度。
在本申请的一些实施方式中，所述双极性集流体与所述外包装连接处，封印厚度T与封印宽度W满足T/W≤0.05，优选0.02≤T/W≤0.04。
在本申请中，所述“封印”是指，外包装的密封区域。例如，图4为本申请一种实施方式的主视图，外包装的密封区域40的厚度T即封印厚度T；图5为本申请一种实施方式的俯视图，外包装的密封区域40的宽度W即封印宽度W。当T/W≤0.05时，可以实现优异的封装可靠性，否则，会因封印厚度和封印宽度不合适而降低封装效果。在本申请中，封印宽度和封印厚度没有特别限制，只要比值满足要求即可，本领域技术人员可以根据具体的电池尺寸进行选择，例如封印宽度优选为1mm至7mm。
在本申请中，所述电极组件的类型没有特别限制，例如可以包括卷绕结构或叠片结构中的至少一种。
在本申请的一些实施方式中，所述电极组件的结构包括卷绕结构，电极组件从正极 极片和负极极片上分别至少引出一个正极极耳和一个负极极耳。
在本申请的一些实施方式中，所述电极组件的结构为叠片结构，电极组件包含多个极耳，可以是从每一层正极极片和负极极片上分别引出一个正极极耳和一个负极极耳，最终一个叠片结构的电极组件包含多组正极极耳和负极极耳，然后经转接焊转极耳引出金属片。
在本申请中，对极耳的焊接方式不做特别限定，只要能实现本申请的目的即可。例如，激光焊、超声焊或电阻焊等中的至少一种。
在本申请的一些实施方式中，双极性集流体可引出极耳，也可不引出极耳，当双极性集流体引出极耳时，可以用于监测单个电极组件的电压。
在本申请中，所述极耳引出的方向没有特别限定，只要能实现本申请的目的即可。例如，极耳引出的方向可以为同向或异向。
本申请第二方面提供了一种电子装置，其包含本申请第一方面所提供的电化学装置。
本申请所述的电子装置包括本领域一般的电子装置，例如笔记本电脑、手机、电动摩托车、电动汽车、电动玩具、储能系统、无人机、电动工具、扫地机器人、平板电脑、电网、电动船等。
本领域中所用的术语一般为本领域技术人员常用的术语，如果与常用术语不一致，以本申请中的术语为准。
测试方法：
输出电压测试方法：
在测试对比例1的输出电压时，测试温度为25±3℃，将锂离子电池以0.5C恒定电流充电至4.2V，然后以4.2V恒定电压充电至电流0.05C，静置1小时，测量开路电压。
在测试对比例2-3和实施例1-25的输出电压时，测试温度为25±3℃，将锂离子电池以0.5C恒定电流充电至8.4V，然后以8.4V恒定电压充电至电流0.05C，静置1小时，测量开路电压。
50个充放电循环(cycle)后的放电容量/首次放电容量η测试方法：
在测试对比例1时，测试温度为25±3℃，将锂离子电池以0.5C恒定电流充电至4.2V，然后以4.2V恒定电压充电至电流0.05C，静置10min，然后0.5C电流放电至3.0V，记录首次放电容量为Q1D，如此重复循环50次，记录此时放电容量为Q50D，则50个充放电循环后的放电容量/首次放电容量保持率：η(％)＝Q50D/Q1D×100％；
在测试对比例2-3和实施例1-25时，测试温度为25±3℃，将锂离子电池以0.5C恒定电流充电至8.4V，然后以8.4V恒定电压充电至电流0.05C，静置10min，然后0.5C电流放电至6.0V，记录首次放电容量为Q1D，如此重复循环50次，记录此时放电容量为Q50D，则50个充放电循环后的放电容量/首次放电容量保持率：η(％)＝Q50D/Q1D×100％。
双极性集流体Z方向的电子电阻率的测试方法：
取10cm×10cm的双极性集流体样品，将双极性集流体的正极侧与负极侧通过两个面积固定的金属夹板夹住，其中夹板面积与双极性集流体相同，在两夹板间施加0.1V电压，并测量两夹板之间的电流值，然后计算电阻值R，再根据以下公式计算Z方向的电子电阻率：ρ＝RS/L。式中，R表示电阻值，S表示双极性集流体的面积，L表示双极性集流体的厚度。
双极性集流体渗水率的测试方法：
将一定厚度的双极性集流体安置于夹持机构上，边缘通过橡胶大压力压紧。在装置的一侧A营造固定温湿度的环境，另一侧B安放一水汽质谱检测探头，两侧气体交换仅可以通过双极性集流体。测试过程先将双极性集流体固定，对腔体B抽真空，排出内部的水汽。后将质谱仪打开，该质谱仪持续接受来自腔体A渗透而过的水汽，并将其转换为电信号输出。持续上述测试24h或更长，得到该段时间内水的渗透总量m，渗透总量m除以时间、水蒸气分压、渗透面积、双极性集流体厚度即可获得水汽渗透率，单位g/(day·m 2·Pa·3mm)。
以下，举出实施例及对比例来对本申请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，“％”为重量基准。
实施例1
<负极极片的制备>
将负极活性材料石墨(Graphite)、导电炭黑(Super P)、丁苯橡胶(SBR)按照重量 比96:1.5:2.5进行混合，然后加入去离子水作为溶剂，调配成为固含量为70％的浆料，并搅拌均匀。将浆料均匀涂覆在厚度为8μm的负极集流体铜箔的一个表面上，110℃条件下烘干，得到涂层厚度为130μm的单面涂布负极活性材料的负极极片。以上步骤完成后，即已完成负极极片的单面涂布。之后，在该负极极片的另一个表面上重复以上步骤，即得到双面涂布负极活性材料的负极极片。涂布完成后，将极片裁切成41mm×61mm的规格待用。
<正极极片的制备>
将正极活性材料钴酸锂(LiCoO 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在厚度为10μm的正极集流体铝箔的一个表面上，90℃条件下烘干，得到涂层厚度为110μm的正极极片。以上步骤完成后，即完成正极极片的单面涂布。之后，在该正极极片的另一个表面上，重复以上步骤，即得到双面涂布正极活性材料的正极极片。涂布完成后，将极片裁切成38mm×58mm的规格待用。
<电解液的制备>
在干燥氩气气氛中，首先将有机溶剂碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)以质量比EC:EMC:DEC＝30:50:20混合，然后向有机溶剂中加入锂盐六氟磷酸锂(LiPF 6)溶解并混合均匀，得到锂盐的浓度为1.15mol/L的电解液。
<电极组件的制备>
在上述制备所得的正极极片和负极极片中间放置15μm的PP隔膜，层叠后将四个角固定，形成叠片型电极组件，其中正极极片和负极极片的层数分别为13和14，其中叠片电芯最外围的两个极片均为单面极片，其余均为双面。
<高分子导电集流体的制备>
在不锈钢基板上喷涂PET材料得到PET层，加热PET层使其软化，再植入导电材料MWCNT，随后再次喷涂PET材料形成PET薄膜，过热辊压所得的PET薄膜，用刮刀将PET薄膜从不锈钢基板表面取下，收卷得到PET和MWCNT复合而成的高分子导电集流体。
<锂离子电池的制备>
选用PET和MWCNT复合而成的高分子导电集流体作为双极性集流体，其中，高分子导电集流体的厚度为100μm、Z方向的电子电阻率为0.06Ω·cm、渗水率为5×10 -5g/(day·m 2·Pa·3mm)，该双极性集流体四周边缘处设有密封层，其中，T/W为0.025。
将冲坑成型的一片外包装(厚度为150μm的铝塑膜)置于组装夹具内，坑面朝上，将一个电极组件(以下称为电极组件A)置于坑内，其最上层为负极极片，该负极极片的上表面没有负极活性材料。将电极组件A的正极极耳引出。
然后将双极性集流体放置于电极组件A上，使其与电极组件A的负极极片接触，并施加外力压紧。
在双极性集流体上放置一个电极组件(以下称电极组件B)，使其正极极片与双极性集流体接触，该正极极片下表面未涂覆正极活性材料，并施加外力压紧。然后，将另一片外包装(厚度为150μm的铝塑膜)坑面朝下覆盖于电极组件B之上，将电极组件B的负极极耳引出，留出注液口侧后热封外包装的其他位置，得到组装电极组件，其中，在双极性集流体的两侧形成各自独立的两个腔体。其中，热封温度为180℃，热封压力为0.5MPa。
在组装电极组件的两个腔体单独注入电解液，注液后进行封口。
充放电过程只需连接电极组件A的正极极耳与电极组件B的负极极耳即可。
实施例2
除了按表1所示双极性集流体厚度为15μm以外，其余与实施例1相同。
实施例3
除了按表1所示双极性集流体厚度为5μm以外，其余与实施例1相同。
实施例4
除了按表1所示采用Cu-Al复合集流体，该双极性集流体Z方向的电子电阻率为5.2×10 -10Ω·cm以外，其余与实施例2相同。
实施例5
除了按表1所示采用不锈钢箔集流体，该双极性集流体Z方向的电子电阻率为9.3×10 -10Ω·cm以外，其余与实施例2相同。
实施例6
除了按表1所示双极性集流体Z方向的电子电阻率为30Ω·cm以外，其余与实施例2相同。
实施例7
除了按表1所示双极性集流体Z方向的电子电阻率为1×10 -4Ω·cm以外，其余与实施例2相同。
实施例8
除了按表1所示双极性集流体渗水率为10 -3g/(day·m 2·Pa·3mm)以外，其余与实施例2相同。
实施例9
除了按表1所示双极性集流体渗水率为10 -7g/(day·m 2·Pa·3mm)以外，其余与实施例2相同。
实施例10
除了按表1所示密封材料为对羟基苯甲醛(PHBA)、密封材料熔点为115℃以外，其余与实施例2相同。
实施例11
除了按表1所示密封材料熔点为100℃以外，其余与实施例2相同。
实施例12
除了按表1所示密封材料熔点为200℃以外，其余与实施例2相同。
实施例13
除了按表1所示铝塑膜厚度为60μm以外，其余与实施例2相同。
实施例14
除了按表1所示铝塑膜厚度为500μm以外，其余与实施例2相同。
实施例15
除了按表1所示T/W为0.005以外，其余与实施例2相同。
实施例16
除了按表1所示T/W为0.05以外，其余与实施例2相同。
实施例17
除了锂离子电池的制备过程与实施例1不同以外，其余与实施例1相同。
<锂离子电池的制备>
除了将双极性集流体的极耳引出外，其余与实施例1相同。
实施例18
除了锂离子电池的制备过程与实施例1不同以外，其余与实施例1相同。
<锂离子电池的制备>
选用PET和MWCNT复合而成的高分子导电集流体作为双极性集流体，其中，高分子导电集流体的厚度为15μm、Z方向的电子电阻率为0.06Ω·cm、渗水率为5×10 -5g/(day·m 2·Pa·3mm)，该双极性集流体四周边缘处设有密封层，其中，T/W为0.025，将该双极性集流体的极耳引出。
将冲坑成型的一片外包装(厚度为150μm的铝塑膜)置于组装夹具内，坑面朝上，后将一个电极组件(以下称为电极组件A)置于坑内，其最上层为负极极片，该负极极片的上表面没有负极活性材料。将电极组件A的多个正极极耳引出片通过转焊接方式焊接成一个正极极耳，将该正极极耳引出。
然后将双极性集流体放置于电极组件A上，使其与电极组件A的负极极片接触，并施加外力压紧。
在双极性集流体上放置一个电极组件(以下称电极组件B)，使其正极极片与双极性 集流体接触，该正极极片下表面没有正极活性材料，并施加外力压紧。然后，将另一片外包装(厚度为150μm的铝塑膜)坑面朝下覆盖于电极组件B之上，将电极组件B的多个负极极耳引出片通过转焊接方式焊接成一个负极极耳，将该负极极耳引出，留出注液口侧后热封外包装的其他位置，得到组装电极组件，其中，在双极性集流体的两侧形成各自独立的两个腔体。其中，热封温度为180℃，热封压力为0.5MPa。
在组装电极组件的两个腔体单独注入电解液，注液后进行封口。充放电过程只需连接电极组件A的正极极耳与电极组件B的负极极耳即可。
实施例19
除了锂离子电池的制备过程与实施例1不同以外，其余与实施例1相同。
<锂离子电池的制备>
选用PET和MWCNT复合而成的高分子导电集流体作为双极性集流体，其中，高分子导电集流体的厚度为15μm、Z方向的电子电阻率为0.06Ω·cm、渗水率为5×10 - 5g/(day·m 2·Pa·3mm)，该双极性集流体四周边缘处设有密封层，其中，T/W为0.025，将该双极性集流体的极耳引出。
将冲坑成型的一片外包装(厚度为200μm的铝塑膜)置于组装夹具内，坑面朝上，后将一个电极组件(以下称为电极组件A)置于坑内，其最上层为负极极片，该负极极片的上表面没有负极活性材料。将电极组件A的正极极耳引出。
然后将一个双极性集流体(以下称双极性集流体A)放置于电极组件A上，使其与电极组件A的负极极片接触，并施加外力压紧。
在双极性集流体A上放置一个电极组件(以下称电极组件C)，使其正极极片与双极性集流体A接触，该正极极片下表面没有正极活性材料，并施加外力压紧。
然后将一个双极性集流体(以下称双极性集流体B)放置于电极组件C上，使双极性集流体B与电极组件C的负极极片接触，并施加外力压紧，该负极极片上表面没有负极活性材料。
在双极性集流体B上放置一个电极组件(以下称电极组件B)，使其正极极片与双极性集流体B接触，该正极极片下表面没有正极活性材料，并施加外力压紧。然后，将另 一片外包装(厚度为200μm的铝塑膜)坑面朝下覆盖于电极组件B之上，将电极组件B的负极极耳引出，留出注液口侧后热封外包装的其他位置，得到组装电极组件，其中，在双极性集流体A、B的两侧形成各自独立的三个腔体。其中，热封温度为180℃，热封压力为0.5MPa。
在组装电极组件的三个腔体单独注入电解液，注液后进行封口。
充放电过程只需连接电极组件A的正极极耳与电极组件B的负极极耳即可。
实施例20
除了正极极耳与负极极耳的引出方向相反外，其余与实施例2相同。
实施例21
除了按表1所示双极性集流体Z方向的电子电阻率为4Ω·cm以外，其余与实施例2相同。
实施例22
<负极极片的制备>、<正极极片的制备>、<电解液的制备>、<电极组件的制备>，与实施例1相同。
<高分子导电集流体的制备>
除了导电材料为石墨烯以外，其余与实施例2相同。
<锂离子电池的制备>
除了选用PET和石墨烯复合而成的高分子导电集流体作为双极性集流体、该双极性集流体按表1所示Z方向的电子电阻率为0.1Ω·cm以外，其余与实施例2相同。
实施例23
除了按表1所示密封材料为聚酯以外，其余与实施例2相同。
实施例24
<负极极片的制备>
除了将负极极片裁切成465mm×92mm的规格待用以外，其余与实施例1相同。
<正极极片的制备>
除了将正极极片裁切成480mm×90mm的规格待用以外，其余与实施例1相同。
<电解液的制备>
与实施例1相同。
<电极组件的制备>
将上述制备所得的正极极片和负极极片，以及15μm的PP隔膜，按照正极极片、隔膜、负极极片的顺序叠好，使隔膜处于正极极片和负极极片中间以起到隔离的作用，卷绕得到卷绕型电极组件。
<高分子导电集流体的制备>
与实施例1相同。
<锂离子电池的制备>
除了电极组件为上述卷绕型电极组件外，其余与实施例2相同。
实施例25
<负极极片的制备>、<正极极片的制备>、<电解液的制备>、<电极组件的制备>、<高分子导电集流体的制备>，与实施例24相同。
<锂离子电池的制备>
除了电极组件为上述卷绕型电极组件外，其余与实施例17相同。
实施例1-25的数据和测试结果见表1。
对比例1
<负极极片的制备>、<正极极片的制备>、<电解液的制备>、<电极组件的制备>，与实施例1相同。
<锂离子电池的制备>
将冲坑成型的一片外包装(厚度为150μm的铝塑膜)置于组装夹具内，坑面朝上，将一个电极组件(以下称为电极组件A)置于坑内。然后，将另一片外包装(厚度为150μm的铝塑膜)坑面朝下覆盖于电极组件A之上，将电极组件A的正负极极耳引出，留出注液口侧后热封外包装的其他位置，得到组装电极组件。其中，热封温度为180℃，热封压力为0.5MPa。
充放电过程只需连接电极组件A的正极极耳与负极极耳即可。
对比例2
<负极极片的制备>、<正极极片的制备>、<电解液的制备>、<电极组件的制备>，与实施例1相同。
<锂离子电池的制备>
将冲坑成型的一片外包装(厚度为150μm的铝塑膜)置于组装夹具内，坑面朝上，将一个电极组件(以下称为电极组件A)置于坑内，其最上层为负极极片，该负极极片的上表面没有负极活性材料。将电极组件A的正极极耳引出。
在电极组件A上放置一个电极组件(以下称电极组件B)，使电极组件B的正极极片与电极组件A的负极极片接触，该正极极片下表面没有正极活性材料，并施加外力压紧。然后，将另一片外包装(厚度为150μm的铝塑膜)坑面朝下覆盖于电极组件B之上，将电极组件B的负极极耳引出，留出注液口侧后热封外包装的其他位置，得到组装电极组件。其中，热封温度为180℃，热封压力为0.5MPa。
在组装电极组件内注入电解液，注液后进行封口。
充放电过程只需连接电极组件A的正极极耳与电极组件B的负极极耳即可。
对比例3
<负极极片的制备>、<正极极片的制备>、<电解液的制备>、<电极组件的制备>，与实施例1相同。
<锂离子电池的制备>
将冲坑成型的一片外包装(厚度为150μm的铝塑膜)置于组装夹具内，坑面朝上，后将一个电极组件(以下称为电极组件A)置于坑内，其最上层为隔膜。将电极组件A 的正负极极耳引出。
在电极组件A上放置一个电极组件(以下称电极组件B)，使电极组件B的隔膜与电极组件A的隔膜侧接触，该隔膜上方为正极极片，并施加外力压紧。然后，将另一片外包装(厚度为150μm的铝塑膜)坑面朝下覆盖于电极组件B之上，将电极组件B的正负极极耳引出，留出注液口侧后热封外包装的其他位置，得到组装电极组件。其中，热封温度为180℃，热封压力为0.5MPa。
在组装电极组件中注入电解液，注液后进行封口。
将电极组件A的负极极耳与电极组件B的正极极耳通过激光焊焊接在一起，使电极组件A、B串联。
充放电过程只需连接电极组件A的正极极耳与电极组件B的负极极耳即可。
对比例1-3的数据和测试结果见表1。
表1各实施例及对比例的的制备参数及测试结果
Figure PCTCN2020099419-appb-000001
Figure PCTCN2020099419-appb-000002
Figure PCTCN2020099419-appb-000003
通过本申请实施例1-25和对比例1-3可以看出，通过双极性集流体内串联后的电化学装置(例如，实施例1-25)，具有更高的输出电压，并且电化学装置在50个充放电循环后，本申请实施例1-25的放电容量/首次放电容量显著提高。
可见，本申请提供的电化学装置，通过双极性集流体串联电极组件，且双极性集流体四周与外包装密封，将电池分割为多个独立的密封腔体，多个电极组件之间实现液态串联电池多电极组件间的离子隔绝，避免发生内短路或电解液高压分解的安全隐患，从而提高了电化学装置的安全性能，保证了高电压电池有效的电能输出。此外，通过卷绕或叠片的结构和双极性集流体的设计，实现电极组件的内部串联，从而无需通过多个电极组件间极耳的焊接实现串联的结构设计，在简化工序、提高生产效率的同时，避免焊接带来的电化学装置串联不良的问题，大大提高了电化学装置的制造可靠性，有利于电能的输出。另外，极耳数量的降低在一定程度上有效提高了高输出电压电池的能量密度。
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 (14)

  1. 一种电化学装置，其包含双极性集流体与电极组件，所述电极组件位于所述双极性集流体的两侧，且两侧电极组件各自靠近所述双极性集流体的最外层极片的极性不同。
  2. 根据权利要求1所述的电化学装置，所述双极性集流体的一侧和与其相邻的电极组件的最外层正极极片电连接，所述双极性集流体的另一侧和与其相邻的电极组件的最外层负极极片电连接。
  3. 根据权利要求1所述的电化学装置，所述双极性集流体与外包装连接，在所述双极性集流体两侧形成各自独立的密封腔体，每个密封腔体中包含一个电极组件和电解液。
  4. 根据权利要求3所述的电化学装置，所述电解液包括有机溶剂。
  5. 根据权利要求1所述的电化学装置，其中，所述双极性集流体还包括密封区域，所述密封区域与外包装密封连接，所述密封区域包含密封材料，所述密封材料的熔点为100℃至200℃。
  6. 根据权利要求5所述的电化学装置，其中，所述双极性集流体包括Cu-Al复合集流体、不锈钢箔集流体或高分子导电集流体中的至少一种；
    所述密封材料包括聚丙烯、聚酯或对羟基苯甲醛中的至少一种。
  7. 根据权利要求1所述的电化学装置，其中，所述双极性集流体的Z方向的电子电阻率为1×10 -11Ω·cm至30Ω·cm。
  8. 根据权利要求1所述的电化学装置，其中，所述双极性集流体渗水率M≤10 -3g/(day·m 2·Pa·3mm)。
  9. 根据权利要求1所述的电化学装置，其中，所述双极性集流体厚度为2μm至100μm。
  10. 根据权利要求3所述的电化学装置，其中，所述双极性集流体与所述外包装连接处，封印厚度T与封印宽度W满足T/W≤0.05，其中，T和W的单位为mm。
  11. 根据权利要求10所述的电化学装置，其具有以下特征中的至少一个：
    a.所述电化学装置包含2至3个双极性集流体；
    b.所述密封材料的熔点为110℃至180℃；
    c.所述双极性集流体的Z方向的电子电阻率为1×10 -5Ω·cm至5Ω·cm；
    d.所述双极性集流体渗水率M≤10 -4g/(day·m 2·Pa·3mm)；
    e.所述双极性集流体厚度为5μm至50μm；
    f.所述封印厚度T与所述封印宽度W满足0.02≤T/W≤0.04。
  12. 根据权利要求11所述的电化学装置，其具有以下特征中的至少一个：
    1).所述密封材料的熔点为120℃至160℃；
    2).所述双极性集流体的Z方向的电子电阻率为0.01Ω·cm至0.10Ω·cm；
    3).所述双极性集流体厚度为5μm至20μm。
  13. 根据权利要求1所述的电化学装置，其中，所述电极组件的结构包括卷绕结构或叠片结构中的至少一种。
  14. 一种电子装置，其包含权利要求1-13任一项所述的电化学装置。
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