WO2021108947A1 - 电池包以及电芯 - Google Patents

电池包以及电芯 Download PDF

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Publication number
WO2021108947A1
WO2021108947A1 PCT/CN2019/122334 CN2019122334W WO2021108947A1 WO 2021108947 A1 WO2021108947 A1 WO 2021108947A1 CN 2019122334 W CN2019122334 W CN 2019122334W WO 2021108947 A1 WO2021108947 A1 WO 2021108947A1
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Prior art keywords
electrode collector
negative electrode
positive electrode
layer
battery pack
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PCT/CN2019/122334
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English (en)
French (fr)
Inventor
程骞
张雅
蔡毅
李晨
Original Assignee
合肥国轩高科动力能源有限公司
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Application filed by 合肥国轩高科动力能源有限公司 filed Critical 合肥国轩高科动力能源有限公司
Priority to EP19954796.9A priority Critical patent/EP4071878A4/en
Priority to PCT/CN2019/122334 priority patent/WO2021108947A1/zh
Priority to JP2022532634A priority patent/JP2023503696A/ja
Priority to CN201980102531.2A priority patent/CN114762171A/zh
Priority to US17/780,527 priority patent/US20220416305A1/en
Publication of WO2021108947A1 publication Critical patent/WO2021108947A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/471—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
    • H01M50/48—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/514—Methods for interconnecting adjacent batteries or cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/521—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the material
    • H01M50/522—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/521—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the material
    • H01M50/524—Organic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/521—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the material
    • H01M50/526—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the material having a layered structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/545—Terminals formed by the casing of the cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • This specification relates to the technical field of lithium ion secondary batteries, and in particular to a battery pack and a battery cell.
  • lithium-ion batteries have become the most important power source for new energy vehicles.
  • people are constantly seeking to maximize the cruising range, charging speed, and lower costs.
  • the industry is still pursuing higher energy density of lithium-ion batteries, but compared to increasing the energy density of a single lithium-ion battery, the energy of the entire battery pack is increased while ensuring safety.
  • the density meets the requirements of electric vehicles for battery pack design.
  • the design of battery packs usually consists of a combination of multiple cells to form a battery module, which is then packaged to form a battery pack.
  • This design increases the complexity and space utilization of the battery pack design, and cannot maximize the energy density of the battery pack. .
  • this specification provides a battery pack and a battery cell, which can maximize the volumetric energy density of the battery pack. Adopting the design of stacking single cells in series, the electrode surface can get a uniform current density during charging and discharging, which is suitable for high current fast charging.
  • the technical solutions provided are as follows:
  • a battery pack the battery pack includes a plurality of electric cores, two adjacent electric cores are connected by a conductive adhesive layer, and the electric cores include a positive electrode collector and a positive electrode stacked in a thickness direction.
  • a plurality of the battery cells are sequentially stacked along the thickness direction to form the battery pack, and the battery pack can form a current channel along the thickness direction during charging and discharging;
  • the conductive bonding layer has two main surfaces opposite to each other, one main surface is connected to the positive electrode collector in the cell, and the other main surface is connected to the negative electrode collector in the cell.
  • the battery pack has a positive electrode collector and a negative electrode collector disposed opposite to each other at both ends in the thickness direction of the battery pack, and the positive electrode collector has a first end surface facing away from the conductive bonding layer.
  • the negative electrode collector has a second end surface facing away from the conductive bonding layer, the battery pack has a battery pack side surface enclosed between the first end surface and the second end surface, and the battery pack side surface An encapsulation layer is applied on it.
  • the positive electrode collector and the negative electrode collector in the cell have a non-conductive matrix, the matrix has a horizontal direction perpendicular to its thickness direction, and the positive electrode collector is A plurality of first conductive paths are arranged at intervals in the horizontal direction of the base, and a plurality of second conductive paths are arranged at intervals in the horizontal direction of the negative electrode collector.
  • the area of the positive electrode collector and the negative electrode collector in the cell is greater than 0.25 m 2 .
  • the conductive adhesive layer includes a resin material and conductive particles.
  • the separator includes: a body layer, the body layer has two opposite sides; adhesive layers respectively provided on both sides of the body layer, the adhesive layer and the positive electrode There is a predetermined binding force between the layer and the negative electrode layer.
  • the predetermined adhesion force is greater than 80 N/m.
  • a battery cell including:
  • a positive electrode collector Including: a positive electrode collector, a positive electrode layer, a separator, a negative electrode layer, and a negative electrode collector that are sequentially stacked along the thickness direction;
  • the positive electrode collector has a first surface and a second surface opposite to each other;
  • the negative electrode collector specifically a third surface and a fourth surface that are opposite to each other, wherein the fourth surface and the second surface face each other;
  • the positive electrode layer is disposed on the second surface
  • the negative electrode layer is disposed on the fourth surface
  • the separator is fixed between the positive electrode layer and the negative electrode layer; the battery core can form a current channel along the thickness direction during charging and discharging.
  • the positive electrode collector and the negative electrode collector have a non-conductive substrate, the substrate has a horizontal direction perpendicular to its thickness direction, and the positive electrode collector is in the horizontal direction of the substrate.
  • a plurality of first conductive paths are arranged on the upper space, and the first conductive paths extend from the first surface to the second surface in the thickness direction; the negative electrode collectors are spaced apart in the horizontal direction of the substrate.
  • a plurality of second conductive paths are provided, and the second conductive paths extend from the fourth surface to the third surface in the thickness direction.
  • the positive electrode collector is provided with a conductive first adhesion layer on the first surface; the negative electrode collector is provided with a conductive second adhesion layer on the third surface Floor.
  • the separator includes: a body layer, the body layer has two opposite sides; adhesive layers respectively provided on both sides of the body layer, the adhesive layer and the positive electrode There is a predetermined binding force between the layer and the negative electrode layer.
  • This application adopts a battery pack formed by a design of stacking cells in series, and the battery pack can achieve a relatively large output voltage.
  • the current can only form a current channel in the thickness direction of the battery pack, and the electrode surface can obtain a uniform current density during charging and discharging without local overheating, which is suitable for fast charging or discharging with high working current.
  • the compact design of the battery cell stack in series can maximize the use of space and maximize the volumetric energy density of the battery pack.
  • the battery core provided by the embodiments of the present application eliminates the electrode tabs, and in the same current, the collector surface can obtain a uniform lower current density, thereby avoiding the problems of uneven current distribution and uneven heat distribution.
  • FIG. 1 is a schematic diagram of the structure of a battery pack provided by an embodiment of this application;
  • Fig. 2 is a schematic diagram of a battery cell structure provided by an embodiment of the application.
  • FIG. 3 is a schematic diagram of a cell packaging structure provided by an embodiment of the application.
  • the battery pack includes a plurality of battery cells 10, two adjacent battery cores 10 are connected by a conductive adhesive layer 7, and the battery cells 10 include a positive electrode collector 1, a positive electrode, which are stacked along the thickness direction.
  • the battery pack is formed by sequentially stacking a plurality of battery cells 10 in series.
  • each single cell 10 is assembled through a conductive adhesive layer 7 and can be electrically and mechanically connected.
  • the conductive bonding layer 7 has two main surfaces opposite to each other, one main surface is connected to the positive electrode collector 1 in the battery core 10, and the other main surface is connected to the negative electrode collector 4 in the battery core 10.
  • the conductive adhesive layer 7 is located between two adjacent battery cores 10 and is used to connect the positive electrode collector 1 and the negative electrode collector 4 of the two adjacent battery cores 10.
  • the positive electrode collector 1 and the negative electrode collector 4 in the two adjacent battery cells 10 are not all located on the same battery core 10.
  • the positive electrode collector 1 is the lower battery core connected to one main surface of the conductive bonding layer 7 10 or the collector in the upper cell 10, and the negative collector 4 is the collector in the upper cell 10 or the lower cell 10 connected to the other main surface of the conductive adhesive layer 7.
  • one main surface of the conductive adhesive layer 7 is used to connect the negative electrode collector 4 in the upper cell 10, and the other main surface of the conductive adhesive layer 7 is used to connect the lower cell 10
  • the positive electrode collector 1 in the middle, so as to realize the series connection of two adjacent cells 10.
  • the definitions of the "upper layer” and “lower layer” directions in this specification are only for the convenience of explaining the technical solutions of this application, and do not limit the battery packs of the embodiments of this application to include, but not limited to, use and testing. , Transportation, manufacturing, and other directions in the scene that may cause the orientation to be reversed or the position to change.
  • the conductive bonding layer 7 includes resin material and conductive particles.
  • the conductive particles can be carbon black, carbon nanotubes, graphene, etc., or nano or micro metal particles, such as Ni, Pt, Au, Ti, SUS, etc.
  • the metal that undergoes the alloying reaction with lithium ions may also contain one or more filler metal particles at the same time.
  • the resin part of the conductive adhesive layer 7 can be acrylic resin, butyl rubber, high content vinyl acetate (EVA), styrene block copolymer.
  • the resin part can also be formulated as a special tackifier based on hot melt PSA (pressure sensitive adhesive), natural rubber, nitrile rubber, silicone rubber, MQ silicate resin, and the tackifier is made of monofunctional trimethylsilane ("M”) and tetrafunctional silicon tetrachloride (“Q”) reaction composition.
  • M monofunctional trimethylsilane
  • Q tetrafunctional silicon tetrachloride
  • the thickness of the conductive adhesive layer 7 is less than 20 ⁇ m.
  • the battery pack adopts a design of a single cell 10 stacked in series, which can maximize the volumetric energy density of the battery pack. Therefore, the number of battery cells that need to be connected in series can be determined according to the voltage of the designed battery pack. For example, using LFP cells (average voltage 3.2V), an 800V battery pack requires 250 cells in series.
  • the upper surface of the collector of the uppermost cell 10 can be used as the positive electrode of the entire battery pack, and the lower surface of the collector of the lowermost cell 10 can serve as the negative electrode of the entire battery pack.
  • each cell 10 includes a positive electrode collector 1 and a negative electrode collector 4.
  • the positive electrode collector 1 and the negative electrode collector 4 are used to converge the current generated by the active material of the battery, so as to form a larger current for external output.
  • the positive electrode collector 1 and the negative electrode collector 4 may be metal foils, such as copper foil, aluminum foil, and the like.
  • the positive electrode collector 1 and the negative electrode collector 4 may also be made of stainless steel.
  • the positive electrode collector 1 and the negative electrode collector 4 may also be conductive polymer collectors mixed with conductive particles and resin materials.
  • the thickness of the positive electrode collector and the negative electrode collector should both be less than 20 ⁇ m, preferably less than 15 ⁇ m, and more preferably less than 10 ⁇ m.
  • the positive electrode collector 1 in the battery cell 10 has a first surface and a second surface opposite to each other, and the first surface and the second surface are the two main surfaces of the positive electrode collector 1 ,
  • the positive electrode layer 2 of the battery cell 10 is provided on the second surface.
  • the negative electrode collector 4 has a third surface and a fourth surface opposite to each other.
  • the third surface and the fourth surface are the two main surfaces of the negative electrode collector 4, and the fourth surface is provided with a battery cell. 10 of the negative electrode layer 3. That is, the first surface of the positive electrode collector 1 forms the positive electrode of the single cell 10, and the third surface of the negative electrode collector 4 forms the negative electrode of the single cell 10.
  • the first surface of the positive electrode collector 1 in the uppermost cell 10 of the battery pack serves as the positive electrode of the entire battery pack
  • the negative electrode collector 4 in the lowermost cell 10 of the battery pack The third surface serves as the negative electrode of the entire battery pack.
  • the first surface of the positive electrode collector 1 in the uppermost cell 10 and the third surface of the negative collector 4 in the lowermost cell 10 form the two end faces of the battery pack.
  • both ends of the battery pack along its thickness direction have a positive electrode collector 1 and a negative electrode collector 4 arranged opposite to each other.
  • the positive electrode collector 1 serves as the positive electrode of the entire battery pack, and the negative electrode
  • the collector 4 serves as the negative electrode of the entire battery pack.
  • the positive electrode collector 1 has a first end surface facing away from the conductive bonding layer 7, the negative electrode collector 4 has a second end surface facing away from the conductive bonding layer 7, the first end surface and the second end surface
  • the end faces are defined as the two end faces of the battery pack.
  • the battery pack has a battery pack side surface enclosed between the first end surface and the second end surface, and an encapsulation layer 6 is laid on the battery pack side surface to form a complete battery pack.
  • the battery core 10 has a side surface of the battery core 10 surrounding the first surface of the positive electrode collector 1 to the third surface of the negative electrode collector 4, and the battery core 10
  • the encapsulation layer 6 is provided on the side surface.
  • the encapsulation layer 6 may be provided on each single cell 10.
  • the first surface of the positive electrode collector 1 and the third surface of the negative electrode collector in the single cell 10 are defined as two end surfaces of the cell 10, and the surface of the cell 10 between the two end faces forms the side of the cell 10.
  • the side surface of the battery core 10 may be flush with the side surface of the positive electrode layer 2, the side surface of the separator 5, and the side surface of the negative electrode layer 3, that is, projected along the thickness direction of the battery core 10, the positive electrode collector 1, The positive electrode layer 2, the separator 5, the negative electrode layer 3, and the negative electrode collector 4 completely overlap.
  • the side surface of the battery cell 10 may cover the side surface of the positive electrode layer 2, the side surface of the separator 5, and the side surface of the negative electrode layer 3.
  • the packaging layer 6 is covered on the side surface of the battery core 10.
  • the encapsulation layer 6 may be a CPP (Cast polypropylene, cast polypropylene) film, which is compounded on the side surface of the electric core 10 by hot pressing.
  • Both the positive electrode layer 2 and the negative electrode layer 3 in the battery cell 10 are coated on one main surface of the collector electrode by a single-sided coating method, that is, the positive electrode layer is coated on one side of the positive electrode collector 1
  • the second surface of the negative electrode layer 3 is coated on the fourth surface of the negative electrode collector 4 on one side.
  • a single battery cell 10 can form the size of a battery pack, and the capacity (Ah) of the entire battery pack is the capacity of a single battery pack 10, which can more effectively utilize the internal space of the battery pack.
  • the first surface of the positive electrode collector 1 in the single cell 10 serves as the positive electrode of the battery
  • the third surface of the negative electrode collector 4 in the single cell 10 serves as the negative electrode of the battery.
  • the area of the positive electrode collector 1 and the negative electrode collector 4 in the battery core 10 is greater than 0.25 m 2 .
  • EV2 size batteries or soft-pack batteries so that the energy density of the monomer>200Wh/kg (LFP), the energy density of the monomer>290Wh/kg (NCM/NCA).
  • the positive electrode layer 2 includes one or more positive electrode materials of lithium as a positive electrode active material, such as lithium-containing compounds: LFP (LiFePO 4 ), NCM (lithium nickel cobalt manganate), NCA (nickel cobalt Lithium aluminate), LNMO (lithium nickel manganese oxide) or a mixture of two or more of them, etc.
  • the positive electrode layer 2 may also contain other materials, such as a binder and a conductive material, as needed.
  • the conductive material may include carbon materials, such as graphite and carbon black, and one of them may be used alone, or a mixture of a plurality of them may be used.
  • the conductive material may also be a metal material, a conductive polymer or the like, as long as the material has a conductive function.
  • the method for coating the positive electrode layer 2 on the second surface of the positive electrode collector 1 may include: coating with a slurry composed of a positive electrode active material, a conductive material, and a binder dissolved or dispersed in a solvent. Coating on one main surface of the positive electrode collector 1, then evaporating the solvent, and calendering the dried solid substrate to a prescribed thickness.
  • the positive electrode layer 2 may not include a binder, and the conductive material may be a suspension in a non-aqueous liquid electrolyte.
  • the binder used in the traditional electrode may hinder the pore structure of the electrode, thereby reducing or completely blocking the flow of the separator to the active material, and reducing the ion conductivity of the electrode.
  • the conductive material may be a suspension of an electronic conductive material (for example, carbon, metal material, etc.) in a non-aqueous liquid electrolyte, thereby forming a semi-solid slurry. Then the semi-solid slurry is coated on the second surface of the positive electrode collector 1 by a single-sided coating method to form a semi-solid electrode.
  • the semi-solid electrode eliminates the need to evaporate the solvent (water or NMP) in the traditional method. At the same time, the semi-solid electrode can be made into an electrode with a larger thickness and a higher active material loading capacity, which can significantly The total charge capacity and energy density of the battery cell 10 are increased.
  • the negative electrode layer 3 includes graphite, silicon-carbon mixture, SiOx, SnOx, FeOx, or a mixture thereof as a negative electrode active material.
  • the negative electrode layer 3 may also contain other materials, such as a binder and a conductive material, as needed.
  • the conductive material may include carbon materials, such as graphite and carbon black, and one of them may be used alone, or a mixture of a plurality of them may be used.
  • the conductive material may also be a metal material, a conductive polymer or the like, as long as the material has a conductive function.
  • the method for coating the negative electrode layer 3 on the fourth surface of the negative electrode collector 4 may include: coating with a slurry composed of a negative electrode active material, a conductive material, and a binder dissolved or dispersed in a solvent. It is coated on one main surface of the negative electrode collector 4, the solvent is evaporated, and the dried solid substrate is rolled to a prescribed thickness.
  • the negative electrode layer 3 may not include a binder, and the conductive material may be a suspension in a non-aqueous liquid electrolyte.
  • the binder used in the traditional electrode may hinder the pore structure of the electrode, thereby reducing or completely blocking the flow of the separator to the active material, and reducing the ion conductivity of the electrode.
  • the conductive material may be a suspension of an electronic conductive material (for example, carbon, metal material, etc.) in a non-aqueous liquid electrolyte, thereby forming a semi-solid slurry. Then the semi-solid slurry is coated on the fourth surface of the negative electrode collector 4 by a single-sided coating method to form a semi-solid electrode.
  • the semi-solid electrode eliminates the need to evaporate the solvent (water or NMP) in the traditional method. At the same time, the semi-solid electrode can be made into an electrode with a larger thickness and a higher active material loading capacity, which can significantly The total charge capacity and energy density of the battery cell 10 are increased.
  • the positive electrode collector 1 is separated from the separator 5 and at least partially defines the positive electrode active area.
  • the positive electrode layer 2 is provided in the positive electrode active area; the negative electrode collector 4 is spaced apart from the separator 5 and at least The negative electrode active area is partially defined, and the negative electrode layer 3 is disposed in the negative electrode active area.
  • the positive electrode layer 2 includes: a suspension of a positive electrode active material and a first conductive material in a first non-aqueous liquid electrolyte;
  • the negative electrode layer 3 includes: a negative electrode active material and a second conductive material in a second non-aqueous liquid electrolyte. Suspension in liquid electrolyte.
  • the positive electrode layer 2 may include about 35% to about 75% by volume of the positive electrode active material, and about 0.5% to about 8% by volume of the first conductive material.
  • the negative electrode layer 3 may include about 35 vol% to about 75 vol% of the negative active material, and about 0.5 vol% to about 8 vol% of the second conductive material.
  • the active material and the conductive material are co-suspended in the electrolyte to prepare a semi-solid electrode.
  • semi-solid refers to a mixed material of liquid and solid phases, such as particle suspensions, colloidal suspensions, emulsions, gels, or micelles.
  • the separator 5 is arranged between the positive electrode layer 2 and the negative electrode layer 3.
  • the separator 5 is used to separate the positive electrode layer 2 and the negative electrode layer 3 to prevent short circuits.
  • the diaphragm 5 may be a porous polymer membrane impregnated with a liquid electrolyte, which allows ions between active materials in the electrodes to reciprocate while preventing electron transfer.
  • the membrane 5 may be a microporous membrane, which prevents particles in the positive and negative electrodes from passing through the membrane.
  • the diaphragm 5 may be any type of membrane capable of ion transport.
  • the separator 5 includes: a body layer, the body layer has two opposite sides; adhesive layers respectively provided on both sides of the body layer, the adhesive layer and the positive electrode layer 2.
  • the negative electrode layer 3 has a predetermined binding force between them.
  • the predetermined adhesive force is greater than 80 N/m, preferably, the predetermined adhesive force is greater than 100 N/m.
  • the body layer may be a PE (Polyethylene, polyethylene) film, or may be a PP (Polypropylene, polypropylene)-based polyolefin separator.
  • Adhesive layers are respectively provided on the two surfaces of the body layer, so as to ensure the bonding strength between the separator 5 and the positive electrode layer 2 and the negative electrode layer 3.
  • the adhesive layer is PVDF (polyvinylidene fluoride), which can significantly improve the adhesion of the separator 5 to the adjacent positive and negative materials, thereby ensuring that the battery core 10 does not need to be added during the charging and discharging process. pressure.
  • the positive electrode collector 1 and the negative electrode collector 4 have a non-conductive substrate, the substrate has a horizontal direction perpendicular to its thickness direction, and the positive electrode collector 1 is at the level of the substrate.
  • a plurality of first conductive paths are arranged at intervals in the direction, and the first conductive paths extend from the first surface of the positive electrode collector 1 to the second surface of the positive electrode collector 1 along the thickness direction;
  • the negative electrode The collector 4 is provided with a plurality of second conductive paths at intervals in the horizontal direction of the substrate, and the second conductive paths extend from the fourth surface of the negative collector 4 to the negative collector along the thickness direction. 4 of the third surface.
  • the positive electrode collector 1 and the negative electrode collector 4 may be polymer collectors provided with conductive fillers. Since the collector electrode is in direct contact with the active material, the material of the collector electrode should not be able to electrochemically react with lithium ions.
  • the substrates of the positive electrode collector 1 and the negative electrode collector 4 are polyolefin materials, such as copolymers or mixtures of high-density polyethylene, low-density polyethylene, polypropylene, polybutene, and polymethylpentene. Compared with the traditional metal collector, the density of the polymer collector is lower than that of metal, which is beneficial to increase the weight energy density of the battery.
  • the conductive filler can form a conductive path in the collector.
  • the first conductive paths in the positive electrode collector 1 may be distributed at predetermined intervals, and the first conductive paths extend from the first surface to the second surface in the thickness direction of the collector, so that the collector is in the thickness direction.
  • a good conductive network can be formed on the surface, and the current can propagate along the thickness direction of the collector electrode along the conductive channel.
  • the first conductive paths are distributed in the matrix of the positive electrode collector 1 at intervals, a sufficient conductive network cannot be formed in the horizontal direction of the collector, so that when a short circuit occurs inside the battery or the acupuncture experiment is performed, the collector is at a horizontal level.
  • the positive electrode collector 1 and the negative electrode collector 4 may be formed by a combination of conductive fillers and polyolefin materials.
  • the conductive fillers can be distributed along the horizontal direction of the collector to form a plurality of first conductive channels and The second conductive channel, so that a conductive network cannot be formed in the horizontal direction of the collector.
  • the positive electrode collector 1 and the negative electrode collector 4 may be processed by combining polyolefin materials with conductive fillers to form first conductive channels and second conductive channels distributed at intervals.
  • the conductive filler is conductive particles, and the conductive particles are any one of the following materials: carbon materials, nano or micro metal particles, and the metal particles cannot undergo an alloying reaction with lithium ions.
  • the mass percentage of conductive particles can be 10 to 70 wt%.
  • the carbon material can be made of materials such as carbon nanotubes, carbon black, Ketjen black, graphene, etc., or a mixture of the above materials, such as a mixture of carbon black + Ketjen black, or carbon black + Ketjen black +Carbon nanotube mixing, etc.
  • the nano or micro metal particles may be metals that do not undergo alloying reaction with lithium ions, such as Ni, Pt, Au, Ti, SUS, etc., and may also contain one or more filler metal particles at the same time.
  • the impedance of the positive electrode collector 1 and the negative electrode collector 4 is lower than 15 mohm/sq. Or, the impedance of the collector is lower than 10mohm/sq.
  • the positive electrode collector 1 is provided with a conductive first adhesion layer on the first surface
  • the negative electrode collector 4 is provided with a conductive second adhesion layer on the third surface.
  • the first adhesion layer and the second adhesion layer can be coated by magnetron sputtering and evaporation on the outer surface of the collector.
  • the first adhesion layer and the second adhesion layer can be, for example, : Ni, Pt, Au, Ti and other conductive metal coatings to further improve the conductivity, and can test voltage, current, and temperature data for BMS (Battery Management System).
  • BMS Battery Management System
  • the thickness of the first adhesion layer and the second adhesion layer is 10 nm or less.
  • the embodiment of the present application also provides a battery cell 10. Please refer to FIGS. 1 to 3.
  • the battery cell 10 includes: a positive electrode collector 1, a positive electrode layer 2, a separator 5, and a negative electrode layer sequentially stacked along the thickness direction. 3.
  • the negative electrode collector 4; the positive electrode collector 1 has a first surface and a second surface opposite to each other; the negative electrode collector 4 has a third surface and a fourth surface opposite to each other, wherein the The fourth surface and the second surface face each other; the positive electrode layer 2 is provided on the second surface; the negative electrode layer 3 is provided on the fourth surface; the separator 5, the separator 5 is fixed Between the positive electrode layer 2 and the negative electrode layer 3; the battery core 10 can form a current path along the thickness direction during charging and discharging.
  • the battery core provided by the embodiment of the application eliminates the electrode tabs, and the collector surface can obtain a uniform current density.
  • the current flows only along the current channel in the thickness direction of the battery core, and the electrode surface can obtain a uniform current density without occurrence Local overheating, suitable for fast charging or discharging with high working current.
  • the battery cell in this application eliminates the electrode tabs in the collector, so that the problems of uneven current distribution and uneven heat distribution can be avoided, and the surface of the collector can obtain a uniform current density.
  • the battery pack formed by the design of single cell stack in series in this application can achieve a larger output voltage.
  • the current only flows in the thickness direction of the battery pack, so that the electrode surface can obtain a uniform current density during charging and discharging. , No local overheating occurs, suitable for fast charging or discharging with high working current.
  • the present application adopts a new type of collector, which can achieve low conductivity in the horizontal direction of the collector and high conductivity in the thickness direction of the collector, which ensures the safety of the battery.
  • the new collector used in this application can reduce the weight of the collector compared with the traditional collector, and increase the weight and energy density of the entire battery pack.

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Abstract

本申请提供了一种电池包以及电芯，所述电池包包括多个电芯，相邻两个所述电芯之间通过导电粘结层连接，所述电芯包括沿着厚度方向叠置的：正极集电极、正极层、隔膜、负极层、负极集电极；多个所述电芯沿着所述厚度方向依次堆叠形成所述电池包，所述电池包在充放电时能形成沿着所述厚度方向的电流通道；其中，所述导电粘结层具有相背对的两个主表面，一个主表面连接所述电芯中的正极集电极，另一个主表面连接所述电芯中的负极集电极。本申请的电池包，电流只在电池包的厚度方向流动，电极表面在充放电时可以得到均匀的电流密度，不会发生局部过热，适合大工作电流快速充电或放电。

Description

电池包以及电芯 技术领域
本说明书涉及锂离子二次电池技术领域，尤其涉及一种电池包以及电芯。
背景技术
近年来，锂离子电池已成为新能源汽车最重要的动力源。随着电动车的普及，人们不断的追求最大化续航里程，充电速度，和更低的成本等。为了提高电动汽车的续航里程，行业内部还在不断追求锂离子电池更高的能量密度，但相比较于提高单个锂离子电池的能量密度，在保证安全性的情况下，提高整个电池包的能量密度才符合电动车对电池包设计的要求。
目前，电池包的设计通常是由多个电芯组合形成电池模组，再封装形成电池包，该种设计增加了电池包设计的复杂性和空间利用率，无法实现电池包能量密度的最大化。
发明内容
鉴于此，本说明书提供了一种电池包以及电芯，能够最大化电池包的体积能量密度。采用单体电芯串联叠层的设计，电极表面在充放电时能得到均匀的电流密度，适合大电流快充。提供的技术方案如下所述：
一种电池包，所述电池包包括多个电芯，相邻两个所述电芯之间通过导电粘结层连接，所述电芯包括沿着厚度方向叠置的：正极集电极、正极层、隔膜、负极层、负极集电极；
多个所述电芯沿着所述厚度方向依次堆叠形成所述电池包，所述电池包在充放电时能形成沿着所述厚度方向的电流通道；
其中，所述导电粘结层具有相背对的两个主表面，一个主表面连接所述电芯中的正极集电极，另一个主表面连接所述电芯中的负极集电极。
作为一种优选的实施方式，所述电池包沿其厚度方向的两端具有相背对设置的正极集电极和负极集电极，所述正极集电极具有背离所述导电粘结层的第一端面，所述负极集电极具有背离所述导电粘结层的第二端面，所述电池包具有围设在所述第一端面和所述第二端面之间的电池包侧面，所述电池包侧面上敷设有封装层。
作为一种优选的实施方式，所述电芯中的所述正极集电极和所述负极集电极具有不导电的基体，所述基体具有垂直于其厚度方向的水平方向，所述正极集电极在所述基体的水平方向上间隔设置有多个第一导电通路，所述负极集电极在所述基体的水平方向上间隔设置有多个第二导电通路。
作为一种优选的实施方式，所述电芯中的所述正极集电极和所述负极集电极的面积大于0.25m 2。
作为一种优选的实施方式，所述导电粘结层包括树脂材料与导电粒子。
作为一种优选的实施方式，所述隔膜包括：本体层，所述本体层具有相背对的两面；分别设置在所述本体层两面上的粘接层，所述粘接层与所述正极层、所述负极层之间具有预定粘结力。
作为一种优选的实施方式，所述预定粘结力大于80N/m。
一种电芯，包括：
包括：沿着厚度方向依次叠置的正极集电极、正极层、隔膜、负极层、负极集电极；
所述正极集电极，具有相背对的第一表面和第二表面；
所述负极集电极，具体相背对的第三表面和第四表面，其中，所述第四表面和所述第二表面相面对；
所述正极层设置在所述第二表面上；
所述负极层设置在所述第四表面上；
隔膜，所述隔膜固定在所述正极层与所述负极层之间；所述电芯在充放电时能形成沿着所述厚度方向的电流通道。
作为一种优选的实施方式，所述正极集电极和所述负极集电极具有不导电的基体，所述基体具有垂直于其厚度方向的水平方向，所述正极集电极在所述基体的水平方向上间隔设置有多个第一导电通路，所述第一导电通路沿所述厚度方向自所述第一表面延伸至所述第二表面；所述负极集电极在所述基体的水平方向上间隔设置有多个第二导电通路，所述第二导电通路沿所述厚度方向自所述第四表面延伸至所述第三表面。
作为一种优选的实施方式，所述正极集电极在所述第一表面上设置有能导电的第一附着层；所述负极集电极在所述第三表面上设置有能导电的第二附着层。
作为一种优选的实施方式，所述隔膜包括：本体层，所述本体层具有相背对的两面；分别设置在所述本体层两面上的粘接层，所述粘接层与所述正极层、所述负极层之间具有预定粘结力。
有益效果：
本申请采用电芯串联叠层的设计形成的电池包，电池包可达到较大的输出电压。通过采用串联堆叠的设计方式，电流只在电池包的厚度方向能形成电流通道，电极表面在充放电时可以得到均匀的电流密度，不会发生局部过热，适合大工作电流快速充电或放电。另外，通过电芯串联叠层的紧凑设计可以最大化的利用空间，实现电池包体积能量密度最大化。本申请实施方式提供的电芯，取消了电极极耳，在相同大小的电流中，集电极表面能够得到均匀的较低的电流密度，从而能够避免电流分布不均匀以及热分布不均匀的问题。
附图说明
图1为本申请实施方式提供的电池包结构示意图；
图2为本申请实施方式提供的电芯结构示意图；
图3为本申请实施方式提供的电芯封装结构的示意图。
附图标记说明：
1、正极集电极；2、正极层；3、负极层；4、负极集电极；5、隔膜；6、封装层；7、导电粘结层；10、电芯。
具体实施方式
下面将结合附图和具体实施方式，对本申请的技术方案作详细说明，应理解这些实施方式仅用于说明本申请而不用于限制范围，在阅读了本申请之后，本领域技术人员对本申请的各种等价形式的修改均落入本申请所附权利要求所限定的范围内。
下面将结合图1至图3对本申请实施例的电芯以及电池包进行解释和说明。需要说明的是，为了便于说明，在本申请实施例中，相同的附图标记表示相同的部件。而为了简洁，在不同的实施例中，省略对相同部件的详细说明，且相同部件的说明可互相参照和引用。
请参阅图1和图2所示，本申请实施方式提供了一种电池包。所述电池包包括多个电芯10，相邻两个所述电芯10之间通过导电粘结层7连接，所述电芯10包括沿着厚度方向叠置的：正极集电极1、正极层2、隔膜5、负极层3、负极集电极4；多个所述电芯10沿着所述厚度方向依次堆叠形成所述电池包，所述电池包在充放电时能形成沿着所述厚度方向的电流通道；其中，所述导电粘结层7具有相背对的两个主表面，一个主表面连接所述电芯10中的正极集电极1，另一个主表面连接所述电芯10中的负极集电极4。
具体的，该电池包通过多个电芯10依次堆叠串联形成。为了降低相邻两个电芯10界面的电子阻抗和保持电池包整体的机械性能，每个单体电芯10之间通过导电粘结层7组装，并能实现电性连接以及机械连接。
所述导电粘结层7具有相背对的两个主表面，一个主表面连接所述电芯10中的正极集电极1，另一个主表面连接所述电芯10中的负极集电极4。请参考图1所示的电池包结构，导电粘结层7位于相邻两个电芯10之间，用于连接相邻两个电芯10中的正极集电极1和负极集电极4，其中，所述相邻两个电芯10中的正极集电极1和负极集电极4并非均位于同一电芯10上，正极集电极1为导电粘结层7的一个主表面所连接的下层电芯10或上层电芯10中的集电极，负极集电极4为导电粘结层7的另一个主表面所连接的上层电芯10或下层电芯10中的集电极。以图1所示的 方向为例，导电粘结层7的一个主表面用于连接上层电芯10中的负极集电极4，导电粘结层7的另一个主表面用于连接下层电芯10中的正极集电极1，从而实现相邻两个电芯10的串联。值得注意的是，本说明书中的对“上层”、“下层”方向的定义，只是为了说明本申请技术方案的方便，并不限定本申请实施例的电池包在包括但不限定于使用、测试、运输和制造等等其他可能导致方位发生颠倒或者位置发生变换的场景中的方向。
所述导电粘结层7包括树脂材料与导电粒子，导电粒子可以为碳黑，碳纳米管，石墨烯等，也可以为纳米或者微米金属颗粒，例如Ni,Pt,Au,Ti,SUS等不于锂离子发生合金化反应的金属，也可以同时含有一种或者几种填充金属粒子。导电粘结层7的树脂部分可以为丙烯酸树脂、丁基橡胶，高含量的乙酸乙烯酯(EVA)、苯乙烯嵌段共聚物。该树脂部分还可以配制成基于热熔PSA(pressure sensitive adhesive)、天然橡胶、丁腈橡胶、硅橡胶、MQ硅酸盐树脂形成的特殊增粘剂，该增粘剂由单官能三甲基硅烷(“M”)与四官能四氯化硅(“Q”)反应组成。优选的，所述导电粘结层7的厚度低于20μm。
所述电池包采用单个电芯10串联叠层的设计，能够最大化电池包的体积能量密度。从而可以根据设计的电池包的电压来决定需要串联的电芯个数。比如，采用LFP电芯(平均电压3.2V)，800V的电池包需要垂直串联250个电芯。其中，最上层电芯10的集电极的上表面可以作为整个电池包的正极，最下层电芯10的集电极的下表面可以作为整个电池包的负极。
如图2所示的单体电芯结构，每个单体电芯10均包括有正极集电极1和负极集电极4。所述正极集电极1和所述负极集电极4用于将电池活性物质产生的电流进行汇聚，以便形成较大的电流对外输出。在一些实施例中，所述正极集电极1和所述负极集电极4可以为金属箔，如铜箔、铝箔等。在一些实施例中，所述正极集电极1和所述负极集电极4也可以采用不锈钢材质。在一些实施例中，所述正极集电极1和所述负极集电极4还可以为混合有导电粒子、树脂材料的导电聚合物集电极。
优选的，所述正极集电极和所述负极集电极的厚度均应小于20μm，优选的小于15μm，更优选的小于10μm。
具体的，所述电芯10中的所述正极集电极1具有相背对的第一表面和第二表面，所述第一表面和所述第二表面为正极集电极1的两个主表面，在所述第二表面设置有电芯10的正极层2。所述负极集电极4具有相背对的第三表面和第四表面，所述第三表面和所述第四表面为负极集电极4的两个主表面，所述第四表面设置有电芯10的负极层3。即，所述正极集电极1的第一表面形成单体电芯10的正极，所述负极集电极4的第三表面形成单体电芯10的负极。
当多个电芯10依次堆叠形成电池包，电池包的最上层电芯10中正极集电极1的第一表面作为整个电池包的正极，电池包的最下层电芯10中负极集电极4的第三表面作为整个电池包的负 极，其中，最上层电芯10中正极集电极1的第一表面以及最下层电芯10中负极集电极4的第三表面形成了电池包的两个端面。
在本申请实施方式提供的电池包中，电池包沿其厚度方向的两端具有相背对设置的正极集电极1和负极集电极4，该正极集电极1作为整个电池包的正极，该负极集电极4作为整个电池包的负极。所述正极集电极1具有背离所述导电粘结层7的第一端面，所述负极集电极4具有背离所述导电粘结层7的第二端面，所述第一端面和所述第二端面定义为电池包的两个端面。所述电池包具有围设在所述第一端面和所述第二端面之间的电池包侧面，所述电池包侧面上敷设有封装层6，从而形成完整的电池包。
如图2和图3所示，所述电芯10具有围设在所述正极集电极1第一表面至所述负极集电极4第三表面之间的电芯10侧面，所述电芯10侧面上设置所述封装层6。
具体的，所述封装层6可以设置在每个单体电芯10上。单体电芯10中的正极集电极1的第一表面和负极集电极的第三表面定义为电芯10的两个端面，两端面之间的电芯10表面形成电芯10侧面。所述电芯10侧面可以与所述正极层2的侧面、所述隔膜5的侧面、所述负极层3的侧面平齐，即，沿电芯10的厚度方向做投影，正极集电极1、正极层2、隔膜5、负极层3、负极集电极4完全重叠。或者，所述电芯10侧面可以覆盖所述正极层2的侧面、所述隔膜5的侧面、所述负极层3的侧面。如图3所示，所述封装层6覆设于所述电芯10侧面上。所述封装层6可以为CPP(Cast polypropylene，流延聚丙烯)薄膜，通过热压复合于电芯10侧面上。
所述电芯10中的正极层2和所述负极层3均采用单面涂布的方法涂层在集电极的一个主表面上，即，所述正极层单面涂布在正极集电极1的第二表面，所述负极层3单面涂布在负极集电极4的第四表面。
在一些实施例中，单个电芯10可以形成电池包的尺寸，及整个电池包的容量(Ah)为单个电芯10的容量，可以更有效的利用电池包的内部空间。从而，单个电芯10中正极集电极1的第一表面作为电池的正极，单个电芯10中负极集电极4的第三表面作为电池的负极。
优选的，所述电芯10中的所述正极集电极1和所述负极集电极4的面积大于0.25m 2。远大于目前的PHEV2、EV2尺寸的电芯或者软包电芯，使得单体的能量密度>200Wh/kg(LFP),单体的能量密度>290Wh/kg(NCM/NCA)。
所述正极层2包括作为正极活性材料的锂的一种或多种正极材料，所述正极活性材料例如含锂化合物：LFP(LiFePO 4)、NCM(镍钴锰酸锂)、NCA(镍钴铝酸锂)，LNMO(锂镍锰氧)或者它们中的两种或多种形成的混合物等。除了上述正极活性材料，所述正极层2还可以根据需要包含其他材料，诸如粘合剂和导电材料。其中，所述导电材料可以包括碳材料，诸如石墨和炭黑，可以单独使用其中一种，或可以使用其中多种的混合物。所述导电材料也可以是金属材料、导电 聚合物或类似物，只要该材料具备导电功能即可。在一些实施例中，所述正极层2涂布在正极集电极1第二表面上方法可以包括：用由溶解或分散在溶剂中的正极活性材料、导电材料和粘合剂构成的浆料涂覆在正极集电极1的一个主表面上，再蒸发溶剂，并压延干燥的固体基质至规定的厚度。
在一些实施中，所述正极层2可以不包括粘合剂，所述导电材料可以为在非水液体电解质中的悬浮液。在传统电极中使用的粘合剂可能阻碍电极的孔结构，从而降低或完全阻隔离子流动至活性材料，降低了电极的离子传导性。所述导电材料可以为电子性的导电材料(例如，碳、金属材料等)在非水液体电解质中的悬浮液，从而形成半固态浆料。然后将该半固态浆料采用单面涂布的方法涂在正极集电极1的第二表面上形成半固态电极。该半固态电极省去了传统方法中的蒸发溶剂(水或者NMP)步骤，同时该半固态电极可以被制成具有较大厚度的电极，具有更高的活性材料载入量，从而能够显著地增加了电芯10总的电荷容量和能量密度。
所述负极层3包括作为负极活性材料的石墨、硅碳混合物、SiOx、SnOx、FeOx或者其混合物等。除了上述负极活性材料，所述负极层3还可以根据需要包含其他材料，诸如粘合剂和导电材料。其中，所述导电材料可以包括碳材料，诸如石墨和炭黑，可以单独使用其中一种，或可以使用其中多种的混合物。所述导电材料也可以是金属材料、导电聚合物或类似物，只要该材料具备导电功能即可。在一些实施例中，所述负极层3涂布在负极集电极4第四表面上方法可以包括：用由溶解或分散在溶剂中的负极活性材料、导电材料和粘合剂构成的浆料涂覆在负极集电极4的一个主表面上，再蒸发溶剂，并压延干燥的固体基质至规定的厚度。
在一些实施例中，所述负极层3可以不包括粘合剂，所述导电材料可以为在非水液体电解质中的悬浮液。在传统电极中使用的粘合剂可能阻碍电极的孔结构，从而降低或完全阻隔离子流动至活性材料，降低了电极的离子传导性。所述导电材料可以为电子性的导电材料(例如，碳、金属材料等)在非水液体电解质中的悬浮液，从而形成半固态浆料。然后将该半固态浆料采用单面涂布的方法涂在负极集电极4的第四表面上形成半固态电极。该半固态电极省去了传统方法中的蒸发溶剂(水或者NMP)步骤，同时该半固态电极可以被制成具有较大厚度的电极，具有更高的活性材料载入量，从而能够显著地增加了电芯10总的电荷容量和能量密度。
如图2所示的电芯结构，正极集电极1与隔膜5间隔开并至少部分地限定了正极活性区域，正极层2设置在正极活性区域中；负极集电极4与隔膜5间隔开并至少部分地限定了负极活性区域，负极层3设置在负极活性区域中。
优选的，所述正极层2包括：正极活性材料和第一导电材料在第一非水液体电解质中的悬浮液；所述负极层3包括：负极活性材料和第二导电材料在第二非水液体电解质中的悬浮液。其中，正极层2可以包括约35体积％至约75体积％的正极活性材料，以及约0.5体积％至约8体积％的第 一导电材料。负极层3可以包括约35体积％至约75体积％的负极活性材料，以及约0.5体积％至约8体积％的第二导电材料。其中，活性材料和导电材料共悬浮在电解质中以制备半固态电极。其中，“半固态”的概念是指液相和固相的混合的材料，例如，如粒子悬浮液、胶体悬浮液、乳液、凝胶或胶束。
所述隔膜5设置在正极层2和负极层3之间。隔膜5用于将正极层2和负极层3分隔开来，防止短路。在一些实施例中，所述隔膜5可以是注入了液体电解质的多孔聚合物膜，其允许电极中的活性物质之间的离子往复运动，同时防止电子转移。在一些实施例中，所述隔膜5可以是微孔膜，其防止正负电极中的粒子穿过该膜。总之，隔膜5可以是能够进行离子运输的任意一种膜。
在本实施例中，所述隔膜5包括：本体层，所述本体层具有相背对的两面；分别设置在所述本体层两面上的粘接层，所述粘接层与所述正极层2、所述负极层3之间具有预定粘结力。所述预定粘结力大于80N/m，优选的，所述预定粘结力大于100N/m。
进一步的，所述本体层可以是PE(Polyethylene，聚乙烯)膜，也可以为PP(Polypropylene,聚丙烯)为主的聚烯烃类隔膜。在所述本体层的两个表面上分别设置有粘接层，从而能够保证隔膜5与正极层2、负极层3之间的粘结强度。优选的，所述粘接层为PVDF(聚偏氟乙烯)，该粘接层可以显著提高隔膜5对相邻正负极材料的粘结力，从而保证电芯10在充放电过程中无需外加压力。
在本实施方式中，所述正极集电极1和所述负极集电极4具有不导电的基体，所述基体具有垂直于其厚度方向的水平方向，所述正极集电极1在所述基体的水平方向上间隔设置有多个第一导电通路，所述第一导电通路沿所述厚度方向自所述正极集电极1的第一表面延伸至所述正极集电极1的第二表面；所述负极集电极4在所述基体的水平方向上间隔设置有多个第二导电通路，所述第二导电通路沿所述厚度方向自所述负极集电极4的第四表面延伸至所述负极集电极4的第三表面。
具体的，所述正极集电极1和负极集电极4可以为设置有导电填充物的聚合物集电极。由于集电极与活性物质直接接触，所述集电极的材料应当不能和锂离子发生电化学反应。正极集电极1和负极集电极4的基体为聚烯烃材料，比如高密度聚乙烯、低密度聚乙烯、聚丙烯、聚丁烯、聚甲基戊烯等的共聚物或者混合体。相较于传统的金属集电极，所述聚合物集电极密度低于金属，从而有利于提高电池的重量能量密度。
所述导电填充物在集电极中能形成导电通路。其中，正极集电极1中的第一导电通路可以按预定间距间隔分布，且第一导电通路沿集电极的厚度方向自所述第一表面延伸至所述第二表面，从而集电极在厚度方向上可以形成较好的导电网络，电流能沿导电通道自集电极的厚度方向传播。同时，由于第一导电通路在正极集电极1的基体中间隔分布，使得集电极的水平方向上未能形成 充分的导电网络，从而在电池内部发生短路或进行针刺实验时，集电极在水平方向上不容易激活多数的活性物质从而不易发生热失控，但又能在集电极的厚度方向上充分的导电，使得电芯10以及电池包可以正常的充放电。同样的，所述负极集电极4中的第二导电通路的设置以及导电原理与正极集电极1相同，本申请在此不再做赘述。
在一些实施例中，所述正极集电极1和负极集电极4可以是导电填充物与聚烯烃材料组合形成，该导电填充物能沿集电极的水平方向间隔分布形成若干个第一导电通道和第二导电通道，从而在集电极的水平方向上无法形成导电网络。在一些实施例中，所述正极集电极1和负极集电极4可以通过将聚烯烃材料与导电填充物复合后，进行工艺加工从而能形成间隔分布的第一导电通道和第二导电通道。所述导电填充物为导电粒子，所述导电粒子为以下任意一种材料：碳材料、纳米或微米金属颗粒，所述金属颗粒不能与锂离子发生合金化反应。在集电极中，导电粒子的质量百分比可以在10～70wt％。其中，所述碳材料可以采用例如：碳纳米管、炭黑、科琴黑、石墨烯等材质，也可以为上述材料的混合物，例如炭黑+科琴黑混合、或炭黑+科琴黑+碳纳米管混合等。所述纳米或微米金属颗粒可以采用例如：Ni,Pt,Au,Ti,SUS等不于锂离子发生合金化反应的金属，也可以同时含有一种或者几种填充金属粒子。
在本实施方式中，所述正极集电极1和所述负极集电极4的阻抗低于15mohm/sq。或者，集电极的阻抗低于10mohm/sq。
在一些实施例中，所述正极集电极1在所述第一表面上设置有能导电的第一附着层，所述负极集电极4在所述第三表面上设置有能导电的第二附着层。所述第一附着层和所述第二附着层可以采用磁控溅射，蒸镀的方法在集电极的外表面进行涂层，所述第一附着层、所述第二附着层可以为例如：Ni,Pt,Au,Ti等能够导电的金属涂层，从而进一步提高导电性能，并能为BMS(Battery Management System，电池管理系统)测试电压、电流、温度数据。另外，通过在集电极外表面采用金属表面化处理，能够隔绝外部氧气或者水分进入电芯10内部。优选的，所述第一附着层和所述第二附着层的厚度为10nm以下。
本申请实施方式还提供了一种电芯10，请参阅图1至图3所示，电芯10包括：沿着厚度方向依次叠置的正极集电极1、正极层2、隔膜5、负极层3、负极集电极4；所述正极集电极1，具有相背对的第一表面和第二表面；所述负极集电极4，具体相背对的第三表面和第四表面，其中，所述第四表面和所述第二表面相面对；所述正极层2设置在所述第二表面上；所述负极层3设置在所述第四表面上；隔膜5，所述隔膜5固定在所述正极层2与所述负极层3之间；所述电芯10在充放电时能形成沿着所述厚度方向的电流通道。
本申请实施方式提供的电芯，取消了电极极耳，集电极表面能够得到均匀的电流密度，电流仅在电芯厚度方向上沿电流通道流动，电极表面可以得到均匀的电流密度，不会发生局部过热， 适合大工作电流快速充电或放电。
本申请实施方式提供的电池包以及电芯具有以下优点和特点：
(1)本申请中的电芯取消了集电极中的电极极耳，从而能够避免电流分布不均匀以及热分布不均匀的问题，集电极表面能够得到均匀的电流密度。
(2)本申请采用单个电芯串联叠层的设计形成的电池包，能够达到较大的输出电压，另外电流只在电池包厚度方向流动，使得电极表面在充放电时可以得到均匀的电流密度，不会发生局部过热，适合大工作电流快速充电或放电。
(3)本申请采用新型的集电极，可以实现集电极水平方向低导电，集电极厚度方向高导电，保证了电池的安全性。同时，本申请采用的新型集电极相较于传统集电极能够减少集电极重量，提高整个电池包的重量能量密度。
(4)通过电芯串联叠层的紧凑设计可以最大化的利用空间，实现电池包体积能量密度最大化。
应该理解，以上描述是为了进行图示说明而不是为了进行限制。通过阅读上述描述，在所提供的示例之外的许多实施方式和许多应用对本领域技术人员来说都将是显而易见的。因此，本教导的范围不应该参照上述描述来确定，而是应该参照所附权利要求以及这些权利要求所拥有的等价物的全部范围来确定。出于全面之目的，所有文章和参考包括专利申请和公告的公开都通过参考结合在本文中。在前述权利要求中省略这里公开的主题的任何方面并不是为了放弃该主体内容，也不应该认为申请人没有将该主题考虑为所公开的申请主题的一部分。

Claims (11)

  1. 一种电池包，其特征在于，所述电池包包括多个电芯，相邻两个所述电芯之间通过导电粘结层连接，所述电芯包括沿着厚度方向叠置的：正极集电极、正极层、隔膜、负极层、负极集电极；
    多个所述电芯沿着所述厚度方向依次堆叠形成所述电池包，所述电池包在充放电时能形成沿着所述厚度方向的电流通道；
    其中，所述导电粘结层具有相背对的两个主表面，一个主表面连接所述电芯中的正极集电极，另一个主表面连接所述电芯中的负极集电极。
  2. 如权利要求1所述的电池包，其特征在于，所述电池包沿其厚度方向的两端具有相背对设置的所述正极集电极和所述负极集电极，所述正极集电极具有背离所述导电粘结层的第一端面，所述负极集电极具有背离所述导电粘结层的第二端面，所述电池包具有围设在所述第一端面和所述第二端面之间的电池包侧面，所述电池包侧面上敷设有封装层。
  3. 如权利要求1所述的电池包，其特征在于，所述电芯中的所述正极集电极和所述负极集电极具有不导电的基体，所述基体具有垂直于其厚度方向的水平方向，所述正极集电极在所述基体的水平方向上间隔设置有多个第一导电通路，所述负极集电极在所述基体的水平方向上间隔设置有多个第二导电通路。
  4. 如权利要求1所述的电池包，其特征在于，所述电芯中的所述正极集电极和所述负极集电极的面积大于0.25m 2。
  5. 如权利要求1所述的电池包，其特征在于，所述导电粘结层包括树脂材料与导电粒子。
  6. 如权利要求1所述的电池包，其特征在于，所述隔膜包括：本体层，所述本体层具有相背对的两面；分别设置在所述本体层两面上的粘接层，所述粘接层与所述正极层、所述负极层之间具有预定粘结力。
  7. 如权利要求6所述的电池包，其特征在于，所述预定粘结力大于80N/m。
  8. 一种电芯，其特征在于，包括：沿着厚度方向依次叠置的正极集电极、正极层、隔膜、负极层、负极集电极；
    所述正极集电极，具有相背对的第一表面和第二表面；
    所述负极集电极，具体相背对的第三表面和第四表面，其中，所述第四表面和所述第二表面相面对；
    所述正极层设置在所述第二表面上；
    所述负极层设置在所述第四表面上；
    隔膜，所述隔膜固定在所述正极层与所述负极层之间；所述电芯在充放电时能形成沿着所述厚度方向的电流通道。
  9. 如权利要求8所述的电芯，其特征在于，所述正极集电极和所述负极集电极具有不导电的基体，所述基体具有垂直于其厚度方向的水平方向，所述正极集电极在所述基体的水平方向上间隔设置有多个第一导电通路，所述第一导电通路沿所述厚度方向自所述第一表面延伸至所述第二表面；所述负极集电极在所述基体的水平方向上间隔设置有多个第二导电通路，所述第二导电通路沿所述厚度方向自所述第四表面延伸至所述第三表面。
  10. 如权利要求9所述的电芯，其特征在于，所述正极集电极在所述第一表面上设置有能导电的第一附着层；所述负极集电极在所述第三表面上设置有能导电的第二附着层。
  11. 如权利要求10所述的电芯，其特征在于，所述隔膜包括：本体层，所述本体层具有相背对的两面；分别设置在所述本体层两面上的粘接层，所述粘接层与所述正极层、所述负极层之间具有预定粘结力。
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