WO2023097437A1 - 集流体及其制备方法、二次电池、电池模块、电池包和用电装置 - Google Patents

集流体及其制备方法、二次电池、电池模块、电池包和用电装置 Download PDF

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Publication number
WO2023097437A1
WO2023097437A1 PCT/CN2021/134371 CN2021134371W WO2023097437A1 WO 2023097437 A1 WO2023097437 A1 WO 2023097437A1 CN 2021134371 W CN2021134371 W CN 2021134371W WO 2023097437 A1 WO2023097437 A1 WO 2023097437A1
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WIPO (PCT)
Prior art keywords
current collector
layer
strength
battery
metal part
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PCT/CN2021/134371
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English (en)
French (fr)
Inventor
王慢慢
葛销明
欧阳楚英
Original Assignee
宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to CN202180091271.0A priority Critical patent/CN116868379A/zh
Priority to PCT/CN2021/134371 priority patent/WO2023097437A1/zh
Priority to EP21954420.2A priority patent/EP4220780A1/en
Priority to US18/127,040 priority patent/US20230261209A1/en
Publication of WO2023097437A1 publication Critical patent/WO2023097437A1/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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • H01M4/662—Alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/043—Processes of manufacture in general involving compressing or compaction
    • H01M4/0435—Rolling or calendering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/80—Porous plates, e.g. sintered carriers
    • H01M4/808—Foamed, spongy materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of batteries, in particular to a current collector and a preparation method thereof, a secondary battery, a battery module, a battery pack and an electrical device.
  • the secondary battery is a relatively common new energy source.
  • the current collector is an important component of the secondary battery.
  • the current collector not only plays the role of carrying active substances, but also gathers the electrons of the electrochemical reaction to the external circuit, thereby The process of converting chemical energy into electrical energy.
  • the current collector made of metal foam has relatively poor mechanical properties, which leads to the problem that the current collector made of metal foam is prone to being squeezed and damaged during the process of winding into a roll.
  • the present application provides a current collector and its preparation method, a secondary battery, a battery module, a battery pack, and an electrical device, so as to improve the ease of winding the current collector made of foamed metal existing in the prior art into a roll. The problem of being crushed.
  • a current collector includes a strength-enhancing layer and a current-collection layer.
  • the current-collection layer and the strength-enhancing layer are stacked and combined.
  • the current-collection layer includes a foam metal part and a solid metal part.
  • the solid metal part can play a supporting role, which is beneficial to prevent the foam metal part from being crushed and damaged when the current collector is wound into a roll, which will affect the performance of the battery.
  • the solid metal part extends along the length direction of the current collector layer, so that the solid metal part can play a supporting role at various positions in the longitudinal direction of the current collector layer, and avoid foam metal parts at various positions of the current collector layer. Broken by crushing.
  • the current collecting layer includes a plurality of solid metal parts, and a metal foam part is arranged between two adjacent solid metal parts.
  • the solid metal parts located on both sides of the foam metal part can protect the foam metal part, preventing the foam metal part between the two solid metal parts from being squeezed and damaged.
  • the two ends or one end of the strength enhancement layer in the width direction are provided with solid metal parts.
  • the solid metal part at the end of the strength-enhancing layer can not only protect the metal foam part located inside it from being crushed and damaged; furthermore, the solid metal part at the end of the strength-enhancing layer in the width direction is also used for
  • the tabs are formed, and the tabs formed by the solid metal part have the characteristics of high structural strength and good welding performance.
  • the strength-enhancing layer is a sheet-shaped metal layer, which improves the poor mechanical properties of the current collector, and is beneficial to solve the problem of tabs being punched out at the end of the current collector or welding the tabs to conductive parts. problems with easy tearing; or
  • the strength-enhancing layer has a network structure, and the strength-enhancing layer 1 of the network structure is conducive to ensuring the bending resistance of the current collector while enhancing the strength of the current collector, so that the current collector can be easily wound into rolls.
  • the strength enhancement layer is provided with through holes, so that the battery liquid on both sides of the strength enhancement layer 2 can flow into each other.
  • a current collector layer is provided on both sides of the strength enhancement layer, the strength enhancement layer and the two current collector layers are arranged side by side along the thickness direction of the current collector, and the strength enhancement layer is located between the two current collector layers.
  • the porosity of the foamed metal part is 20% to 95%, which ensures that the foamed metal part is in full contact with the active material of the battery and can also ensure that the current collector has good bending resistance.
  • the foamed metal part The porosity of the metal part is 85%-90%, so that the volumetric energy density of the battery is high.
  • the metal foam part includes a channel extending from a side away from the strength-enhancing layer to a side close to the strength-enhancing layer, and the channel is zigzag.
  • the thickness of the strength-enhancing layer is 4-12 ⁇ m, which ensures that the current collector has good mechanical properties and can also ensure that the current collector has good bendability;
  • the thickness of the current collector layer is 20-400 ⁇ m, which ensures that the metal foam part is fully in contact with the active material of the battery, and can also ensure that the current collector has good bending resistance.
  • the material of the foam metal part is copper
  • the material of the solid metal part is one of copper-zinc, copper-aluminum, copper-manganese and copper-iron alloy; or
  • the material of the foam metal part is nickel, and the material of the solid metal part is nickel-manganese alloy; or
  • the material of the foam metal part is titanium, and the material of the solid metal part is one of titanium-scandium, titanium-copper and platinum-titanium-copper alloy; or
  • the material of the foam metal part is gold, and the material of the solid metal part is gold-silver alloy.
  • a method for preparing a current collector including:
  • a bonding step comprising laminating the alloy foil for forming the current collecting layer and the strength enhancing layer, and bonding the two;
  • the foaming step includes applying a layer of anti-corrosion material locally on the alloy foil to form an intermediate to be foamed and placing the intermediate in a corrosive solution to remove the part of the alloy foil that is not coated with an anti-corrosion material layer
  • One or more elements of the alloy foil are used to form a foamed metal part, and part of the alloy foil coated with a layer of anti-corrosion material forms a solid metal part.
  • the corrosive solution includes at least one of a dilute hydrochloric acid solution, an ammonium sulfate solution, an electrolyte mixed with H 2 SO 4 and MnSO 4 , an acetic acid solution, a phosphoric acid solution, and a sulfuric acid solution.
  • the alloy foil used to form the current collector layer and the strength enhancing layer are bonded by rolling.
  • a secondary battery including the above current collector or the current collector prepared by the above preparation method.
  • a battery module is also provided, and the battery module includes the above-mentioned secondary battery.
  • a battery pack is also provided, and the battery pack includes the above-mentioned battery module.
  • an electric device which includes at least one of the above-mentioned secondary battery, battery module or battery pack.
  • Fig. 1 shows a schematic structural diagram of a vehicle disclosed in some embodiments of the present application.
  • Fig. 2 shows a schematic diagram of an exploded structure of a battery pack disclosed in some embodiments of the present application.
  • Fig. 3 shows a schematic diagram of a partial structure of a battery module disclosed in some embodiments of the present application.
  • Fig. 4 shows a schematic structural diagram of a current collector disclosed in some embodiments of the present application.
  • Fig. 5 shows a schematic structural view of a current collector disclosed in other embodiments of the present application.
  • Fig. 6 shows a schematic structural view of a current collector disclosed in other embodiments of the present application.
  • range disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and an upper limit define the boundary of a particular range. Ranges defined in this manner may be inclusive or exclusive and may be combined arbitrarily, ie any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are contemplated.
  • the numerical range "a-b" represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed in sequence, and may also include steps (b) and (a) performed in sequence.
  • steps (c) means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c) , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b) and so on.
  • the “comprising” and “comprising” mentioned in this application mean open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).
  • Power batteries are not only used in energy storage power systems such as hydraulic, thermal, wind and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, as well as military equipment and aerospace and other fields . With the continuous expansion of power battery application fields, its market demand is also constantly expanding.
  • Fig. 1 shows a schematic structural diagram of an electric device using a battery as a power source; as shown in Fig. Extended range cars, etc.
  • the interior of the vehicle 1000 is provided with a battery pack 100 , and the battery pack 100 may be provided at the bottom, head or tail of the vehicle 1000 .
  • the battery pack 100 can be used for power supply of the vehicle 1000 , for example, the battery pack 100 can be used as an operating power source of the vehicle 1000 .
  • the vehicle 1000 may further include a controller 200 and a motor 300 , the controller 200 is used to control the battery pack 100 to supply power to the motor 300 , for example, for starting, navigating, and working power requirements of the vehicle 1000 during driving.
  • the battery pack 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 to provide driving power for the vehicle 1000 instead of or partially replacing fuel oil or natural gas.
  • the battery pack 100 includes a box body 110 and a battery module disposed in the box body 110 , the battery module includes a plurality of battery cells 120 , and the battery cells 120 are accommodated in the box body 110 .
  • the box body 110 is used to provide accommodating space for the battery cells 120 , and the box body 110 may adopt various structures.
  • the box body 110 may include a first part 111 and a second part 112, the first part 111 and the second part 112 cover each other, and the first part 111 and the second part 112 jointly define a battery cell 120. of accommodation space.
  • the second part 112 can be a hollow structure with one end open, the first part 111 can be a plate-shaped structure, and the first part 111 covers the opening side of the second part 112, so that the first part 111 and the second part 112 jointly define an accommodation space
  • the first part 111 and the second part 112 can also be hollow structures with one side opening, and the opening side of the first part 111 covers the opening side of the second part 112 .
  • the box body 110 formed by the first part 111 and the second part 112 may be in various shapes, such as a cylinder, a cuboid, and the like.
  • the battery pack 100 there may be multiple battery cells 120 , and the multiple battery cells 120 may be connected in series, parallel or mixed.
  • a plurality of battery cells 120 can be directly connected in series, in parallel or mixed together, and then the whole composed of a plurality of battery cells 120 is housed in the box 110; of course, the battery pack 100 can also be a plurality of battery cells 120 are firstly connected in series or in parallel or in combination to form a battery module, and then multiple battery modules are connected in series or in parallel or in combination to form a whole, which is accommodated in the box 110 .
  • the battery pack 100 may also include other structures, for example, the battery pack 100 may also include a bus component for realizing the electrical connection between a plurality of battery cells 120 .
  • each battery cell 120 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto.
  • the battery cell 120 may be in the form of a cylinder, a flat body, a cuboid or other shapes.
  • FIG. 3 is a schematic diagram of an exploded structure of a battery cell 120 provided in some embodiments of the present application.
  • the battery cell 120 refers to the smallest unit constituting the battery pack 100 .
  • the battery cell 120 includes an end cover 121 , a casing 122 , a cell assembly 123 and other functional components.
  • the end cap 121 refers to a component that covers the opening of the casing 122 to isolate the internal environment of the battery cell 120 from the external environment.
  • the shape of the end cap 121 can be adapted to the shape of the housing 122 to fit the housing 122 .
  • the end cap 121 can be made of a material with a certain hardness and strength, such as aluminum alloy, so that the end cap 121 is not easily deformed when being squeezed and collided, so that the battery cell 120 can have higher structural strength , safety performance can also be improved.
  • Functional components such as electrode terminals 121 a may be provided on the end cap 121 .
  • the electrode terminal 121 a can be used to be electrically connected with the cell assembly 123 for outputting or inputting electric energy of the battery cell 120 .
  • the end cover 121 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 120 reaches a threshold value.
  • the material of the end cap 21 can also be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application.
  • an insulator can also be provided inside the end cover 121, and the insulator can be used to isolate the electrical connection components in the housing 122 from the end cover 121, so as to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber or the like.
  • the casing 122 is a component used to cooperate with the end cap 121 to form an internal environment of the battery cell 120 , wherein the formed internal environment can be used to accommodate the battery cell assembly 123 , electrolyte and other components.
  • the housing 122 and the end cover 121 can be independent components, and an opening can be provided on the housing 122 , and the internal environment of the battery cell 120 can be formed by making the end cover 121 cover the opening at the opening.
  • the end cover 121 and the housing 122 can also be integrated.
  • the end cover 121 and the housing 122 can form a common connection surface before other components are inserted into the housing. When the inside of the housing 122 needs to be encapsulated , then make the end cover 121 cover the housing 122 .
  • the housing 122 can be in various shapes and sizes, such as cuboid, cylinder, hexagonal prism and so on. Specifically, the shape of the casing 122 can be determined according to the specific shape and size of the battery cell assembly 123 .
  • the housing 122 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application.
  • the cell assembly 123 is a component in the battery cell 100 where electrochemical reactions occur.
  • the casing 122 may contain one or more cell assemblies 123 .
  • the cell assembly 123 is mainly formed by winding or stacking pole pieces, wherein the pole pieces include a positive pole piece and a negative pole piece, and a separator is usually provided between the positive pole piece and the negative pole piece.
  • the pole piece is mainly composed of a sheet-shaped current collector and an active material coated on the current collector.
  • the part of the positive electrode sheet and the negative electrode sheet with the active material constitutes the main body of the cell assembly, and the parts of the positive electrode sheet and the negative electrode sheet without the active material respectively constitute the tab 123a.
  • the positive pole tab and the negative pole tab can be located at one end of the main body together or at two ends of the main body respectively.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode film layer arranged on at least one surface of the positive electrode collector, and the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
  • the positive electrode current collector can be a metal foil or a composite current collector, and the positive electrode current collector can also be the current collector to be protected in this application.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may be a positive electrode active material known in the art for batteries.
  • the positive active material may include at least one of the following materials: olivine-structured lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials of batteries can also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon At least one of a composite material, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also may be abbreviated as LFP)
  • composite materials of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the positive electrode film layer may further optionally include a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer may also optionally include a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode current collector can be a metal foil or a composite current collector, and the negative electrode current collector can also be the current collector claimed in this application, for example, copper foil can be used as the metal foil.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material can be a negative electrode active material known in the art for batteries.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further optionally include a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer may also optionally include a conductive agent.
  • the conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • CMC-Na sodium carboxymethylcellulose
  • the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • electrolytes can be liquid, gel or all solid.
  • the electrolyte is an electrolytic solution.
  • the electrolyte solution includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
  • the solvent may be selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte may optionally include additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of the battery, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of batteries, and the like.
  • a separator is further included in the secondary battery.
  • the present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
  • the inventors of the present application noticed that when the pole piece using the metal foam foil as the current collector is wound into a roll or stacked together with multi-layer pole pieces, the metal foam foil is prone to be crushed and damaged. After the foamed metal foil is damaged, its contact area with the electrolyte is reduced, and the battery's power storage performance is reduced.
  • the inventors found that the current collector adopts the mixed form of metal foam and solid metal, which is beneficial to improve the ability of the current collector to resist extrusion damage.
  • the present application provides a current collector for a battery.
  • the solid metal part 22 can play a supporting role, which is beneficial to avoid the foam metal part 21 being crushed and damaged when the current collector is wound into a roll, which will affect the performance of the battery.
  • the solid metal part 22 extends along the length direction of the current collector layer 2, so that the solid metal part 22 can play a supporting role at various positions in the length direction of the current collector layer 2, and avoids the The metal foam part 21 at the position is damaged due to extrusion.
  • the current collecting layer 2 includes a plurality of solid metal parts 22, a metal foam part 21 is arranged between two adjacent solid metal parts 22, and the solid metal parts 22 on both sides of the foam metal part 21 can It plays the role of protecting the metal foam part 21 and avoids the metal foam part 21 located between the two solid metal parts 22 from being crushed and damaged.
  • both ends or one end of the strength enhancement layer 1 in the width direction are provided with solid metal parts 22 .
  • the solid metal part 22 at the end of the strength-enhancing layer 1 can not only protect the foam metal part 21 located inside it from being crushed and damaged;
  • the part 22 can also be used to form a tab, and the tab formed by the solid metal part 22 has the characteristics of high structural strength and good welding performance.
  • the strength enhancing layer 1 is a sheet metal layer.
  • the sheet-like metal layer in the present application refers to a sheet-like structure made of metal with no pores inside and a non-foam structure. It should be noted that the non-foam structure without pores inside may have through-holes or surface pits.
  • the battery current collector of this embodiment includes a strength-enhancing layer 1, which improves the poor mechanical properties of the current collector and is beneficial to solve the problem that the tabs are easily torn when the tabs are punched out at the end of the current collector or when the tabs are welded to conductive components. The problem.
  • the strength enhancing layer 1 has a mesh structure.
  • the strength-enhancing layer 1 of the network structure is beneficial to ensure the bending resistance of the current collector while enhancing the strength of the current collector, so that the current collector can be easily wound into rolls.
  • the strength enhancement layer 1 is made of copper, and the copper strength enhancement layer 1 not only enhances the mechanical properties of the current collector, but also makes the current collector have good weldability and electrical conductivity. Further, there are also It is beneficial to ensure the bending resistance of the current collector, so as to prevent the current collector from breaking during the winding process.
  • the strength enhancement layer 1 can also choose other materials with better strength, electrical conductivity and plastic toughness, such as nickel, aluminum, iron, magnesium, titanium, steel and alloys.
  • a current collector layer 2 is provided on both sides of the strength enhancement layer 1, the strength enhancement layer 1 and the two current collector layers 2 are arranged side by side along the thickness direction of the current collector, and the strength enhancement layer 1 is located between the two collector layers. between the flow layers 2 so that the current collector satisfies the characteristics of a symmetrical electrode structure.
  • the strength enhancement layer 1 is provided with through holes, so that the battery liquid on both sides of the strength enhancement layer 2 can flow into each other.
  • the porosity of the metal foam portion 21 is 20% to 95%.
  • the porosity of the metal foam part (21) is 85%-90%.
  • Porosity refers to the percentage of the volume of pores inside a porous solid material to the total volume of the material in its natural state. The larger the porosity of the metal foam part 21, the larger the contact area between the metal foam part 21 and the active material of the battery; however, the corresponding bending resistance of the metal foam part 21 becomes worse, and the current collector is wound into a roll. prone to cracking.
  • the porosity of the metal foam part 21 is 20% to 90%. When the metal foam part 21 is fully in contact with the active material of the battery, it can also ensure that the current collector has good bending resistance.
  • the metal foam part 21 has a porosity of 85% to 90%
  • the battery current collector having a metal foam part 21 with a porosity of 85% to 90% has a higher volume energy density of the battery.
  • the metal foam part 21 includes a channel extending from a side away from the strength-enhancing layer 1 to a side close to the strength-enhancing layer 1 , and the channel is zigzag.
  • the following table shows the experimental data of the battery current collector using the technical means of this embodiment and the battery current collector of the comparative example.
  • the embodiments described below are exemplary and are only used for explaining the present application, and should not be construed as limiting the present application. If no specific technique or condition is indicated in the examples, it shall be carried out according to the technique or condition described in the literature in this field or according to the product specification. The reagents or instruments used were not indicated by the manufacturer, and they were all commercially available conventional products.
  • the method for testing the mass energy density of the secondary battery includes the preparation of the secondary battery and testing the mass energy density of the secondary battery.
  • the preparation method of the secondary battery is as follows:
  • LFP LiFePO 4 , lithium iron phosphate
  • Li 6 CoO 4 Li 6 CoO 4 with conductive agent acetylene black and binder polyvinylidene fluoride (PVDF) in a weight ratio of 90.5:4.5:3: 2.
  • PVDF polyvinylidene fluoride
  • a porous polymer film made of polyethylene (PE) is used as a separator.
  • the method of testing the mass energy density of the secondary battery is as follows:
  • the tested discharge capacity value (that is, the initial discharge capacity D0) by the platform voltage U of the system and divide it by the weight W of the battery, which is the mass energy density of the battery.
  • the porosity ⁇ test was carried out by gas adsorption method.
  • Pre-treatment Take an appropriate amount of sample in a special sample tube, heat and evacuate for 2 hours, weigh the total weight after cooling to room temperature, and subtract the mass of the sample tube to obtain the sample mass.
  • Test Put the sample tube into the workstation, measure the adsorption amount of gas on the solid surface under different adsorption pressures at a constant low temperature, and obtain the adsorption amount of the monomolecular layer of the sample based on the BET multilayer adsorption theory and its formula, thereby Calculate the specific surface area per unit mass of solid sample.
  • Adsorption gas nitrogen
  • adsorption pressure points 0.05/0.10/0.15/0.20/0.25/0.30kPa
  • test atmosphere high-purity liquid nitrogen atmosphere, in which the purity of liquid nitrogen is ⁇ 99.99%.
  • Step 1 Obtain 30% Cu-70% Mn alloy by means of vacuum smelting
  • the second step alloy treatment:
  • the alloy treatment includes removing impurities such as oxide scales in the alloy in the first step, and the method of specifically removing impurities such as oxide scales is mechanical grinding;
  • the alloy plate and pure copper foil in the third step are stacked according to the stacking method of alloy plate/copper foil/alloy plate and then hot rolled to obtain a foil with a thickness of 80um.
  • the temperature of hot rolling is 850°C;
  • the width of the glue is 7.5mm, and the glue to be pasted is a commercially available ordinary blue tape with a thickness of 60um.
  • the method is: at room temperature, place the sample in an aqueous hydrochloric acid solution with a concentration of 5wt% for 24 hours. After the corrosion is completed, take out the sample and place it in DI water Ultrasonic cleaning 4h.
  • Step Seven Remove Glue and Dry
  • the part where the glue is applied forms the solid metal part 22; the part where the glue is not applied forms a foam metal part because part of the alloy is corroded by hydrochloric acid.
  • the fabrication process of the current collector of the comparative example is as follows:
  • Step 1 Obtain 20% Cu-80% Mn alloy by means of vacuum smelting
  • Step 1 Obtain 15% Cu-85% Mn alloy by means of vacuum smelting
  • Step 1 Obtain 12% Cu-88% Mn alloy by means of vacuum smelting
  • Step 1 Obtain 10% Cu-90% Mn alloy by means of vacuum smelting
  • the metal foam part 21 of the current collector layer 2 is formed by removing a part of the metal elements in the alloy metal with a corrosive solution, and is not corroded because it is protected by the adhesive. Part of the solid metal part 22 is formed.
  • the material of the foam metal part 21 is copper, and the material of the solid metal part 22 is one of copper-zinc, copper-aluminum, copper-manganese and copper-iron alloy; or, the material of the foam metal part 21 is nickel, and the material of the solid metal part 22
  • the material of the foam metal part 21 is nickel-manganese alloy; or, the material of the foam metal part 21 is titanium, and the material of the solid metal part 22 is one of titanium scandium, titanium copper and platinum-copper alloy; or, the material of the foam metal part 21 is gold,
  • the material of the solid metal part 22 is gold-silver alloy.
  • the strength enhancement layer 1 has a thickness of 4 to 12 ⁇ m.
  • the greater the thickness of the strength-enhancing layer 1 the better the mechanical properties of the current collector, but correspondingly the worse the bendability of the current collector, which makes it difficult for the current collector to be wound into rolls.
  • the thickness of the strength-enhancing layer 1 is 4 to 12 ⁇ m, which ensures that the current collector has good mechanical properties and can also ensure that the current collector has good bendability.
  • the thickness of the current collecting layer 2 is 20-400 ⁇ m. If the thickness of the metal foam part 21 is too small, the pores in the corresponding metal foam part 21 will be less, and the contact surface between the metal foam part 21 and the active material in the battery will be smaller; if the thickness of the metal foam part 21 is too large, then The bending resistance of the metal foam part 21 is deteriorated, and the current collector is prone to cracking during the winding process.
  • the thickness of the metal foam part 21 is 20 to 400 ⁇ m, which ensures that the metal foam part 21 is fully in contact with the active material of the battery, and can also ensure that the current collector has good bending resistance.
  • Fig. 4 shows a schematic structural view of the current collector of some embodiments of the present application.
  • the current collector of this embodiment includes a strength-enhancing layer 1 and two collectors respectively arranged on both sides of the strength-enhancing layer.
  • the current collecting layer 2 wherein the current collecting layer 2 includes a metal foam part 21 and two solid metal parts 22 located at both ends of the metal foam part 21 along the width direction of the current collector.
  • the porosity of the metal foam parts 21 of the two current collecting layers 2 is 85 to 90%.
  • the thickness of current collecting layer 2 is 70 to 80 ⁇ m.
  • the thickness of the strength enhancement layer 1 is 5 to 6 ⁇ m.
  • the solid metal part 22 is located at one end of the current collector layer 2 along the width direction of the current collector and extends along the length direction of the current collector.
  • the width of the solid metal part 22 is 8mm.
  • the solid metal part 22 runs through the entire thickness direction of the current collecting layer 2 .
  • Fig. 5 shows a schematic structural view of the current collector of some embodiments of the present application.
  • the current collector of this embodiment includes a strength-enhancing layer 1 and two collectors respectively arranged on both sides of the strength-enhancing layer.
  • the current collecting layer 2 wherein the current collecting layer 2 includes a metal foam part 21 and two solid metal parts 22 located at both ends of the metal foam part 21 along the width direction of the current collector.
  • the porosity of the metal foam parts 21 of the two current collecting layers 2 is 65 to 80%.
  • the thickness of current collecting layer 2 is 110 to 125 ⁇ m.
  • the thickness of the strength enhancement layer 1 is 5 to 6 ⁇ m.
  • the solid metal part 22 is located at one end of the current collector layer 2 along the width direction of the current collector and extends along the length direction of the current collector.
  • the width of the solid metal part 22 is 7 mm.
  • the solid metal part 22 runs through the entire thickness direction of the current collecting layer 2 .
  • Fig. 6 shows a schematic structural view of the current collector of some embodiments of the present application.
  • the current collector of this embodiment includes a strength-enhancing layer 1 and two collectors respectively arranged on both sides of the strength-enhancing layer.
  • the current collecting layer 2 wherein the current collecting layer 2 includes a metal foam part 21 and two solid metal parts 22 located at both ends of the metal foam part 21 along the width direction of the current collector.
  • the porosity of the metal foam parts 21 of the two current collecting layers 2 is 40 to 55%.
  • the thickness of current collecting layer 2 is 40 to 50 ⁇ m.
  • the thickness of the strength enhancement layer 1 is 7 to 9 ⁇ m.
  • the strength enhancement layer 1 is copper foil with through holes.
  • the solid metal part 22 is located at one end of the current collector layer 2 along the width direction of the current collector and extends along the length direction of the current collector.
  • the width of the solid metal part 22 is 7 mm.
  • the solid metal part 22 runs through the entire thickness direction of the current collecting layer 2 .
  • this embodiment also provides a method for preparing a current collector, including a combining step and a foaming step.
  • the combining step includes stacking the alloy foil for forming the current collecting layer 2 and the strength enhancing layer 1 and combining the above two.
  • the foaming step includes applying a layer of anti-corrosion material locally on the alloy foil to form an intermediate to be foamed and placing the intermediate in a corrosive solution to remove the One or more elements form the alloy foil to form the foamed metal part 21 , and the part of the alloy foil coated with the anti-corrosion material layer forms the solid metal part 22 .
  • the corrosive solution includes at least one of dilute hydrochloric acid solution, ammonium sulfate solution, electrolyte solution mixed with H 2 SO 4 and MnSO 4 , acetic acid solution, phosphoric acid solution and sulfuric acid solution.
  • the concentration of the corrosive solution is 1 vol.% to 85 vol.%.
  • the alloy foil used to form the current collecting layer 2 and the strength enhancing layer 1 are combined by rolling.
  • rolling bonding refers to a bonding method in which the alloy sheets are laminated and then integrated using strong plastic or thermoplastic deformation.

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Abstract

一种集流体及其制备方法、二次电池、电池模块、电池包和用电装置，集流体包括强度增强层(1)和集流层(2)，集流层(2)与强度增强层(1)层叠设置并结合，集流层(2)包括泡沫金属部(21)和实体金属部(22)。实体金属部(22)能够起到支撑作用，有利于避免在集流体被卷绕成卷时泡沫金属部(21)被挤压破损而影响电池的性能。

Description

集流体及其制备方法、二次电池、电池模块、电池包和用电装置 技术领域
本申请涉及电池技术领域，特别是涉及一种集流体及其制备方法、二次电池、电池模块、电池包和用电装置。
背景技术
随着人们对能源需要的不断增长和环境保护意识的不断增强，新型能源越来越受到人们的重视。
二次电池是一种比较常见的新型能源，集流体是二次电池的重要的组成部件，集流体不仅起到承载活性物质的作用，并且将电化学反应的电子汇集起来导至外电路，从而实现化学能转化为电能的过程。泡沫金属材质的集流体力学性能比较差，导致应用泡沫金属材质的集流体在缠绕成卷的过程中容易出现被挤压损坏的问题。
发明内容
本申请提供了一种集流体及其制备方法、二次电池、电池模块、电池包和用电装置，以改善现有技术中存在的泡沫金属材质的集流体在被缠绕成卷的过程中容易被挤压损坏的问题。
根据本申请的一个方面，提供了一种集流体，集流体包括强度增强层和集流层，集流层与强度增强层层叠设置并结合，集流层包括泡沫金属部和实体金属部。实体金属部能够起到支撑作用，有利于避免在集流体被卷绕成卷时泡沫金属部被挤压破损而影响电池的性能。
在一些实施例中，实体金属部沿集流层的长度方向延伸，以使实体金属部能够在集流层的长度方向的各个位置起到支撑作用，避免集流层的各个位置的泡沫金属部因挤压而破损。
在一些实施例中，集流层包括多个实体金属部，相邻的两个实体金属部之间设有泡沫金属部。位于泡沫金属部的两侧的实体金属部能够起到保护泡沫金属部的作用，避免位于两个实体金属部之间的泡沫金属部被挤压破损。
在一些实施例中，强度增强层的宽度方向的两端或一端设有实体金属部。位于强度增强层的端部的实体金属部不仅能起到保护位于其内侧的泡沫金属部免被挤压破损的作用；进一步地位于强度增强层的宽度方向的端部的实体金属部还用于形成极耳，实体金属部形成的极耳具有结构强度高、焊接性能好的特点。
在一些实施例中，强度增强层为片状金属层，改善了集流体的力学性能差，有利于解决在集流体的端部冲切出极耳或将极耳与导电部件焊接时，极耳容易撕裂的问题；或
强度增强层为网状结构，网状结构的强度增强层1在增强集流体的强度的同时，有利于保证集流体的耐弯折性能，以使集流体易于被卷绕成卷。
在一些实施例中，强度增强层上设有通孔，以使强度增强层2的两侧的电池液互相流动。
在一些实施例中，强度增强层的两侧分别设有集流层，强度增强层和两个集流层沿集流体的厚度方向并排布置，且强度增强层位于两个集流层之间。
在一些实施例中，泡沫金属部的孔隙率为20％～95％，在保证泡沫金属部与电池的活性物质充分接触，也能够保证集流体具有良好的耐弯 折性能，可选地，泡沫金属部的孔隙率为85％～90％，以使电池体积能量密度较高。
在一些实施例中，泡沫金属部包括由远离强度增强层一侧向靠近强度增强层一侧延伸的孔道，孔道是曲折的。
在一些实施例中，孔道的曲折度t为1.21～1.33，其中，t＝1+ln(1/ε 2)，ε为孔隙率，曲折度越小对嵌锂过程越有利，以提高电池的充放电性能。
在一些实施例中，强度增强层的厚度为4～12μm，在保证集流体具有良好的力学性能，也能够保证集流体具有良好的易弯折性能；和/或
集流层的厚度为20～400μm，在保证泡沫金属部与电池的活性物质充分接触，也能够保证集流体具有良好的耐弯折性能。
在一些实施例中，泡沫金属部的材质为铜，实体金属部的材质为铜锌、铜铝、铜锰和铜铁合金中的一种；或
泡沫金属部的材质为镍，实体金属部的材质为镍锰合金；或
泡沫金属部的材质为钛，实体金属部的材质为钛钪、钛铜和铂钛铜合金中的一种；或
泡沫金属部的材质为金，实体金属部的材质为金银合金。
据本申请的另一方面，还提供了一种集流体的制备方法，包括：
结合步骤，包括将用于形成集流层的合金箔片和强度增强层叠置，并将上述两者结合；以及
泡沫化步骤，包括在合金箔片的局部贴敷防腐蚀材料层形成待泡沫化的中间体和将中间体置于腐蚀性溶液中，以去除未贴敷防腐蚀材料层的部分合金箔片中的一种或多种元素而将合金箔片形成泡沫金属部，贴敷防腐蚀材料层的部分合金箔片形成实体金属部。
在一些实施例中，腐蚀性溶液包括稀盐酸溶液、硫酸铵溶液、 H 2SO 4和MnSO 4混合而成的电解液、醋酸溶液、磷酸溶液和硫酸溶液中的至少一种。
在一些实施例中，将用于形成集流层的合金箔片和强度增强层的通过轧制结合。
据本申请的另一方面，还提供了一种二次电池，包括上述的集流体或通过上述的制备方法制备的集流体。
据本申请的另一方面，还提供了一种电池模块，电池模块包括上述的二次电池。
据本申请的另一方面，还提供了一种电池包，电池包包上述的电池模块。
据本申请的另一方面，还提供了一种用电装置，用电装置包括选上述的二次电池、电池模块或电池包中的至少一种。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1示出了本申请的一些实施例公开的一种车辆的结构示意图。
图2示出了本申请的一些实施例公开的一种电池组的分解结构示意图。
图3示出了本申请的一些实施例公开的一种电池模组的局部结构示意图。
图4示出了本申请的一些实施例公开的一种集流体的结构示意图。
图5示出了本申请的另一些实施例公开的一种集流体的结构示意图。
图6示出了本申请的另一些实施例公开的一种集流体的结构示意图。
在附图中，附图并未按照实际的比例绘制。
标记说明：
1000、车辆；100、电池；200、控制器；300、马达；110、箱体；111、第一部分；112、第二部分；120、电池单体；121、端盖；121a、电极端子；122、壳体；123、电芯组件；123a、极耳；1、强度增强层；2、集流层；21、泡沫金属部；22、实体金属部。
具体实施方式
下面结合附图和实施例对本申请的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本申请的原理，但不能用来限制本申请的范围，即本申请不限于所描述的实施例。
在本申请的描述中，需要说明的是，除非另有说明，“多个”的含义是两个以上；术语“上”、“下”、“左”、“右”、“内”、“外”等指示的方位或位置关系仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”、“第三”等仅用于描述目的，而不能理解为指示或暗示相对重要性。“垂直”并不是严格意义上的垂直，而是在误差允许范围之内。“平行”并不是严格意义上的平行，而是在误差允许范围之内。
下述描述中出现的方位词均为图中示出的方向，并不是对本申请的具体结构进行限定。在本申请的描述中，还需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接 相连，也可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可视具体情况理解上述术语在本申请中的具体含义。
进一步地，本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举 例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
目前，从市场形势的发展来看，动力电池的应用越加广泛。动力电池不仅被应用于水力、火力、风力和太阳能电站等储能电源系统，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。随着动力电池应用领域的不断扩大，其市场的需求量也在不断地扩增。
图1示出了一种采用电池作为动力源的用电装置的结构示意图；如图1所示，本实施例的用电装置包括车辆1000，该车辆1000可以是纯电动汽车、混合动力汽车或增程式汽车等。车辆1000的内部设置有电池包100，电池包100可以设置在车辆1000的底部或头部或尾部。电池包100可以用于车辆1000的供电，例如，电池包100可以作为车辆1000的操作电源。车辆1000还可以包括控制器200和马达300，控制器200用来控制电池包100为马达300供电，例如，用于车辆1000的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池包100不仅可以作为车辆1000的操作电源，还可以作为车辆1000的驱动电源，代替或部分地代替燃油或天然气为车辆1000提供驱动动力。
请参照图2，图2为本申请一些实施例提供的电池包100的爆炸图。电池包100包括箱体110和设在箱体110内的电池模块，电池模块包括多个电池单体120，电池单体120容纳于箱体110内。其中，箱体110用于为电池单体120提供容纳空间，箱体110可以采用多种结构。在一些实施例中，箱体110可以包括第一部分111和第二部分112，第一部分111与第二部分112相互盖合，第一部分111和第二部分112共同限定出用于容纳电池单体120的容纳空间。第二部分112可以为一端开口的空心结构，第一部分111可以为板状结构，第一部分111盖合于第二部分112的开口侧，以使第一部分111与第二部分112共同限定出容纳空间；第一 部分111和第二部分112也可以是均为一侧开口的空心结构，第一部分111的开口侧盖合于第二部分112的开口侧。当然，第一部分111和第二部分112形成的箱体110可以是多种形状，比如，圆柱体、长方体等。
在电池包100中，电池单体120可以是多个，多个电池单体120之间可串联或并联或混联，混联是指多个电池单体120中既有串联又有并联。多个电池单体120之间可直接串联或并联或混联在一起，再将多个电池单体120构成的整体容纳于箱体110内；当然，电池包100也可以是多个电池单体120先串联或并联或混联组成电池模块形式，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体110内。电池包100还可以包括其他结构，例如，该电池包100还可以包括汇流部件，用于实现多个电池单体120之间的电连接。
其中，每个电池单体120可以为二次电池或一次电池；还可以是锂硫电池、钠离子电池或镁离子电池，但不局限于此。电池单体120可呈圆柱体、扁平体、长方体或其它形状等。
请参照图3，图3为本申请一些实施例提供的电池单体120的分解结构示意图。电池单体120是指组成电池包100的最小单元。如图3，电池单体120包括有端盖121、壳体122、电芯组件123以及其他的功能性部件。
端盖121是指盖合于壳体122的开口处以将电池单体120的内部环境隔绝于外部环境的部件。不限地，端盖121的形状可以与壳体122的形状相适应以配合壳体122。可选地，端盖121可以由具有一定硬度和强度的材质如铝合金制成，这样，端盖121在受挤压碰撞时就不易发生形变，使电池单体120能够具备更高的结构强度，安全性能也可以有所提高。端盖121上可以设置有如电极端子121a等的功能性部件。电极端子121a可以用于与电芯组件123电连接，以用于输出或输入电池单体120的电能。在一些实施例中，端盖121上还可以设置有用于在电池单体120的内部压力或温度达到阈值时泄放内部压力的泄压机构。端盖21的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖121的内侧还可以设置 有绝缘件，绝缘件可以用于隔离壳体122内的电连接部件与端盖121，以降低短路的风险。示例性的，绝缘件可以是塑料、橡胶等。
壳体122是用于配合端盖121以形成电池单体120的内部环境的组件，其中，形成的内部环境可以用于容纳电芯组件123、电解液以及其他部件。壳体122和端盖121可以是独立的部件，可以于壳体122上设置开口，通过在开口处使端盖121盖合开口以形成电池单体120的内部环境。不限地，也可以使端盖121和壳体122一体化，具体地，端盖121和壳体122可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体122的内部时，再使端盖121盖合壳体122。壳体122可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体122的形状可以根据电芯组件123的具体形状和尺寸大小来确定。壳体122的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
电芯组件123是电池单体100中发生电化学反应的部件。壳体122内可以包含一个或更多个电芯组件123。电芯组件123主要由极片卷绕或层叠放置形成，其中，极片包括正极片和负极片，通常在正极片与负极片之间设有隔离膜。
极片主要包括薄片状的集流体和涂敷在集流体上的活性物质构成。正极片和负极片具有活性物质的部分构成电芯组件的主体部，正极片和负极片不具有活性物质的部分各自构成极耳123a。正极极耳和负极极耳可以共同位于主体部的一端或是分别位于主体部的两端。在电池包100的充放电过程中，正极活性物质和负极活性物质与电解液发生反应，极耳123a连接电极端子以形成电流回路。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流 体，正极集流体也可以为本申请所要保护的集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料可采用本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、 石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体，负极集流体也可以为本申请所要求保护的集流体，例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
[隔离膜]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
本申请的发明人注意到，采用泡沫金属箔片作为集流体的极片在卷绕成卷或将多层极片叠置在一起时，泡沫金属箔片容易出现被挤压破损的现象。泡沫金属箔片破损后，其与电解质的接触面积减小，电池的储电性能下降。
为了改善上述的问题，发明人发现集流体采用泡沫金属和实体金属混合的形式，有利于提高集流体的抗挤压破损的能力。
基于上述的目的，本申请提供了一种电池的集流体，如图4所示，该集流体包括强度增强层1和集流层2，集流层2包括泡沫金属部21和实体金属部22，其中，实体金属部22能够起到支撑作用，有利于避免在集流体被卷绕成卷时泡沫金属部21被挤压破损而影响电池的性能。
在一些实施例中，实体金属部22沿集流层2的长度方向延伸，以使实体金属部22能够在集流层2的长度方向的各个位置起到支撑作用，避免集流层2的各个位置的泡沫金属部21因挤压而破损。
在一些实施例中，集流层2包括多个实体金属部22，相邻的两个实体金属部22之间设有泡沫金属部21，位于泡沫金属部21的两侧的实体金属部22能够起到保护泡沫金属部21的作用，避免位于两个实体金属部22之间的泡沫金属部21被挤压破损。
在一些实施例中，强度增强层1的宽度方向的两端或一端设有实体金属部22。位于强度增强层1的端部的实体金属部22不仅能起到保护位于其内侧的泡沫金属部21免被挤压破损的作用；进一步地位于强度增强层1的宽度方向的端部的实体金属部22还可用于形成极耳，实体金属部22形成的极耳具有结构强度高、焊接性能好的特点。
在一些实施例中，强度增强层1为片状金属层。在本申请中的片状金属层是指内部无孔隙的、非泡沫结构的、金属材质的片状结构。需要说明的是，内部无孔隙的非泡沫结构是可以具有贯穿的通孔或表面凹坑的。本实施例的电池集流体包括强度增强层1，改善了集流体的力学性能差，有利于解决在集流体的端部冲切出极耳或将极耳与导电部件焊接时极耳容易撕裂的问题。
在另一些实施例中，强度增强层1为网状结构。网状结构的强度增强层1在增强集流体的强度的同时，有利于保证集流体的耐弯折性能，以使集流体易于被卷绕成卷。
在一些实施例中，强度增强层1的材质为铜，铜质的强度增强层1不仅增强了集流体的力学性能，而且还使得集流体具有良好的焊接性和导电性，进一步地，也有利于保证集流体的耐弯折性，以防止集流体在卷绕成卷的过程中出现断裂。强度增强层1还可以选择其它的具有较好的强度、导电性能和塑韧性的材料，例如镍、铝、铁、镁、钛、钢和合金。
在一些实施例中，强度增强层1的两侧分别设有集流层2，强度增强层1和两个集流层2沿集流体的厚度方向并排布置，且强度增强层1位于两个集流层2之间，以使集流体满足对称式的电极结构的特征。
在一些实施例中，强度增强层1上设有通孔，以使强度增强层2的两侧的电池液互相流动。
泡沫金属部21的孔隙率为20％～95％。可选地，泡沫金属部(21)的孔隙率为85％～90％。孔隙率是指对于多孔的固体材料内部的孔隙的体积占材料自然状态下总体积的百分比。泡沫金属部21的孔隙率越大，泡沫金属部21与电池的活性物质的接触面积越大；但是，相应的泡沫金属部21的耐弯折性能变差，集流体卷绕成卷的过程中容易出现开裂的现象。
泡沫金属部21的孔隙率为20％～90％，在保证泡沫金属部21与电池的活性物质充分接触，也能够保证集流体具有良好的耐弯折性能。
在另一些实施例中，泡沫金属部21的孔隙率为85％至90％，采用泡沫金属部21的孔隙率为85％～90％的电池集流体的电池体积能量密度较 高。
其中泡沫金属部21包括由远离强度增强层1一侧向靠近强度增强层1一侧延伸的孔道，孔道是曲折的。孔道的曲折度t为1.21～1.33，其中，t＝1+ln(1/ε 2)，ε为孔隙率。曲折度越小对嵌锂过程越有利。
下表示出了采用本实施例的技术手段的电池集流体与对比例的电池集流体的实验数据。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
各个实施例以及对比例的电池集流体的参数以及性能试验如下表：
Figure PCTCN2021134371-appb-000001
Figure PCTCN2021134371-appb-000002
表中“/”表示无法测试。
二次电池的质量能量密度的测试方法包括二次电池的制备和测试二次电池的质量能量密度。
其中，二次电池的制备方法如下：
1、将LFP(LiFePO 4，磷酸铁锂)作为正极活性物质和富锂材料Li 6CoO 4与导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比90.5：4.5：3：2在N-甲基吡咯烷酮溶剂体系中充分搅拌混合均匀后，以单位面积涂敷量18.9mg/cm 2涂覆于铝箔上烘干、冷压，得到正极片。
2、将上述实施例1至4与对比例中的集流体直接做为负极片使用。
3，以聚乙烯(PE)制多孔聚合薄膜作为隔离膜。
4、将正极片、隔离膜以及负极片按顺序重叠，使隔离膜处于正负极之间起到隔离的作用，并卷绕得到裸电芯。将裸电芯置于外包装中，注入浓度为1M六氟磷酸锂(20％碳酸亚乙酯和30％碳酸二甲酯为溶剂和50％碳酸甲乙酯)电解液并封装，得到二次电池。
其中，测试二次电池质量能量密度方法如下：
1、将上述制备的各二次电池，分别在25℃恒温环境下，静置10min，后按照1/3C放电至2.5V；再次静置30min后，按照1/3C充电至3.65V；然后在3.65V下恒压充电至电流≤0.05C，再次静置30min，此时的充电容量记为C0，然后按照1/3C放电至2.5V，此时的放电容量为初始放电容量，记为D0。
2、将测试的放电容量值(即初始放电容量D0)乘以体系的平台电压U并除以电池的重量W，即为电池的质量能量密度。
曲折度的测试方法如下：
首先利用气体吸附法进行孔隙率ε测试。
1.前处理：用专用样品管装取适量样品，加热抽真空脱气2h，待冷却至室温后称总重，减去样品管质量得到样品质量。
2.测试：将样品管装入工作站，在恒低温度下，测定不同吸附压力下气体在固体表面的吸附量，基于BET多层吸附理论及其公式求得试样单分子层吸附量，从而计算出单位质量固体样品的比表面积。
3.吸附气体：氮气，吸附压力点分别为：0.05/0.10/0.15/0.20/0.25/0.30kPa，测试氛围：高纯液氮氛围，其中液氮的纯度≥99.99％。
然后，利用BERNARD P.BOUDREAU公式t＝1+ln(1/ε^2)计算得到曲折度。
上述表格中的对比实施例的集流体的制作过程如下：
第一步：通过真空冶炼的方式得到30％Cu-70％Mn合金；
第二步：合金处理：
其中，合金处理包括去除第一步合金中的氧化皮等杂质物，具体地去除氧化皮等杂质的方法采用机械打磨；
第三步：初轧：
将第二步的合金进行初步轧制，轧制成0.1-0.5mm厚的合金板材备用；
第四步：复合轧制：
将第三步的合金板材与纯铜箔按照合金板材/铜箔/合金板材的层叠方式叠好后进行热轧制，得到具有80um厚的箔材，热轧制的温度为850℃；
第五步：贴胶
将第四步的箔材的一端两面贴胶处理，胶的宽度为7.5mm，所贴的胶为市售的厚度60um普通蓝色胶带。
第六步：去合金化
将第五步的箔材进行去合金化腐蚀掉金属Mn，方法为：室温环境下，将样品置于浓度为5wt％的盐酸水溶液中，持续时间为24h，腐蚀结束后取出样品置于DI水中超声清洗4h。
第七步：除胶并干燥
揭掉第五步的胶带，将第六步的样品放在温度为45℃的真空烘箱中烘干得到多孔泡沫集流体。其中，贴胶处的部分形成实体金属部22；未贴胶部分由于部分合金被盐酸腐蚀，因此形成泡沫金属部。
对比例的集流体的制作过程如下：
除不形成加强层以外，同对比实施例一致。
实施例1的集流体的制作过程如下：
第一步：通过真空冶炼的方式得到20％Cu-80％Mn合金；
后续处理步骤同对比实施例一致。
实施例2的集流体的制作过程：
第一步：通过真空冶炼的方式得到15％Cu-85％Mn合金；
后续处理步骤同对比实施例一致。
实施例3的集流体制作过程：
第一步：通过真空冶炼的方式得到12％Cu-88％Mn合金；
后续处理步骤同对比实施例一致。
实施例4的集流体制作过程：
第一步：通过真空冶炼的方式得到10％Cu-90％Mn合金；
后续处理步骤同对比实施例一致。
由以上的对比实施例以及实施例的集流体体的制备过程可知，集流层2的泡沫金属部21通过腐蚀性溶液去除合金金属中的一部分金属元素而形成，而因受贴胶保护未腐蚀的部分形成实体金属部22。
具体地，泡沫金属部21的材质为铜，实体金属部22的材质为铜锌、铜铝、铜锰和铜铁合金中的一种；或，泡沫金属部21的材质为镍，实体金属部22的材质为镍锰合金；或，泡沫金属部21的材质为钛，实体金属部22的材质为钛钪、钛铜和铂铜合金中的一种；或，泡沫金属部21的材质为金，实体金属部22的材质为金银合金。
在一些实施例中，强度增强层1厚度为4至12μm。强度增强层1的厚度越大，集流体的力学性能越好，但是相应地集流体的易弯折性能越差，从而使得集流体不易卷绕成卷。强度增强层1的厚度为4至12μm，在保证集流体具有良好的力学性能，也能够保证集流体具有良好的易弯折性能。
在一些实施例中，集流层2的厚度为20～400μm。泡沫金属部21的厚度过小，则相应的泡沫金属部21内的孔隙也越少，泡沫金属部21与电池内的活性物质的接触面也越小；泡沫金属部21的厚度过大，则泡沫金属部21的耐弯折性能变差，集流体卷绕成卷的过程中容易出现开裂的现象。泡沫金属部21的厚度为20至400μm，在保证泡沫金属部21与电池的活性物质充分接触，也能够保证集流体具有良好的耐弯折性能。
图4示出了本申请的一些实施例的集流体的结构示意图，结合图4所示，本实施例的集流体包括一个强度增强层1和分别设在强度增强层的两侧的两个集流层2，其中，集流层2包括泡沫金属部21和位于泡沫金属部21的沿集流体的宽度方向的两端的两个实体金属部22。两个集流层2的泡沫金属部21的孔隙率为85至90％。集流层2的厚度为70至80μm。强度增强层1的厚度为5至6μm。实体金属部22位于集流层2的沿集流体宽度方向的一端，并沿集流体的长度方向延伸，实体金属部22的宽 度为8mm。实体金属部22贯穿集流层2的整个厚度方向。
图5示出了本申请的一些实施例的集流体的结构示意图，结合图5所示，本实施例的集流体包括一个强度增强层1和分别设在强度增强层的两侧的两个集流层2，其中，集流层2包括泡沫金属部21和位于泡沫金属部21的沿集流体的宽度方向的两端的两个实体金属部22。两个集流层2的泡沫金属部21的孔隙率为65至80％。集流层2的厚度为110至125μm。强度增强层1的厚度为5至6μm。实体金属部22位于集流层2的沿集流体宽度方向的一端，并沿集流体的长度方向延伸，实体金属部22的宽度为7mm。实体金属部22贯穿集流层2的整个厚度方向。
图6示出了本申请的一些实施例的集流体的结构示意图，结合图6所示，本实施例的集流体包括一个强度增强层1和分别设在强度增强层的两侧的两个集流层2，其中，集流层2包括泡沫金属部21和位于泡沫金属部21的沿集流体的宽度方向的两端的两个实体金属部22。两个集流层2的泡沫金属部21的孔隙率为40至55％。集流层2的厚度为40至50μm。强度增强层1的厚度为7至9μm.可选地，强度增强层1为具有通孔的铜箔。实体金属部22位于集流层2的沿集流体宽度方向的一端，并沿集流体的长度方向延伸，实体金属部22的宽度为7mm。实体金属部22贯穿集流层2的整个厚度方向。
根据本申请的另一方面，本实施例还提供了一种集流体的制备方法，包括结合步骤和泡沫化步骤。
其中，结合步骤，包括将用于形成集流层2的合金箔片和强度增强层1叠置并将上述两者结合。
泡沫化步骤包括在合金箔片的局部贴敷防腐蚀材料层形成待泡沫化的中间体和将中间体置于腐蚀性溶液中，以去除未贴敷防腐蚀材料层的部分合金箔片中的一种或多种元素而将合金箔片形成泡沫金属部21，贴敷防腐蚀材料层的部分合金箔片形成实体金属部22。
其中，腐蚀性溶液包括稀盐酸溶液、硫酸铵溶液、H 2SO 4和MnSO 4混合而成的电解液、醋酸溶液、磷酸溶液和硫酸溶液中的至少一种。可选地，腐蚀性溶液的浓度为1vol.％至85vol.％。
其中，将用于形成集流层2的合金箔片和强度增强层1的通过轧制结合。其中，轧制结合是指将合金板层叠后利用强烈的塑性或热塑性变形将板材一体化的结合方式。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (19)

  1. 一种集流体，包括：
    强度增强层(1)；以及
    集流层(2)，与所述强度增强层(1)层叠设置并结合，所述集流层(2)包括泡沫金属部(21)和实体金属部(22)。
  2. 根据权利要求1所述的集流体，其中，所述实体金属部(22)沿所述集流层的长度方向延伸。
  3. 根据权利要求1或2所述的集流体，其中，所述集流层(2)包括多个所述实体金属部(22)，相邻的两个所述实体金属部(22)之间设有所述泡沫金属部(21)。
  4. 根据权利要求1至3中任一项所述的集流体，其中，所述强度增强层(1)的宽度方向的两端或一端设有所述实体金属部(22)。
  5. 根据权利要求1至4中任一项所述的集流体，其中，
    所述强度增强层(1)为片状金属层；或
    所述强度增强层(1)为网状结构。
  6. 根据权利要求5所述的集流体，其中，所述强度增强层(1)上设有通孔。
  7. 根据权利要求1至6中任一项所述的集流体，其中，所述强度增强层(1)的两侧分别设有所述集流层(2)，所述强度增强层(1)和两个所述集流层(2)沿集流体的厚度方向并排布置，且所述强度增强层(1)位于两个所述集流层(2)之间。
  8. 根据权利要求1至7中任一项所述的集流体，其中，所述泡沫金属部(21)的孔隙率为20％～95％，可选地，所述泡沫金属部(21)的孔隙率为85％～90％。
  9. 根据权利要求1至8中任一项所述的集流体，其中，所述泡沫金属部(21)包括由远离所述强度增强层(1)一侧向靠近所述强度增强层(1)一侧延伸的孔道，所述孔道是曲折的。
  10. 根据权利要求9所述的集流体，其中，所述孔道的曲折度t为1.21～1.33，其中，t＝1+ln(1/ε 2)，ε为孔隙率。
  11. 根据权利要求1至10中任一项所述的集流体，其中，
    所述强度增强层(1)的厚度为4～12μm；和/或
    所述集流层(2)的厚度为20～400μm。
  12. 根据权利要求1至11中任一项所述的集流体，其中，
    所述泡沫金属部(21)的材质为铜，实体金属部(22)的材质为铜锌、铜铝、铜锰和铜铁合金中的一种；或
    所述泡沫金属部(21)的材质为镍，实体金属部(22)的材质为镍锰合金；或
    所述泡沫金属部(21)的材质为钛，实体金属部(22)的材质为钛钪、钛铜和铂钛铜合金中的一种；或
    所述泡沫金属部(21)的材质为金，实体金属部(22)的材质为金银合金。
  13. 一种集流体的制备方法，包括：
    结合步骤，包括将用于形成所述集流层(2)的合金箔片和所述强度增强层(1)叠置，并将上述两者结合；以及
    泡沫化步骤，包括在所述合金箔片的局部贴敷防腐蚀材料层形成待泡沫化的中间体和将所述中间体置于腐蚀性溶液中，以去除未贴敷所述防腐蚀材料层的部分所述合金箔片中的一种或多种元素而将所述合金箔片形成所述泡沫金属部(21)，贴敷所述防腐蚀材料层的部分所述合金箔片形成所述实体金属部(22)。
  14. 根据权利要求13所述的制备方法，其中所述腐蚀性溶液包括稀盐酸溶液、硫酸铵溶液、H 2SO 4和MnSO 4混合而成的电解液、醋酸溶液、磷酸溶液和硫酸溶液中的至少一种。
  15. 根据权利要求13或14所述的制备方法，其中，将用于形成所述集流层(2)的合金箔片和所述强度增强层(1)的通过轧制结合。
  16. 一种二次电池，包括权利要求1至15任一项所述的集流体或通过权利要求13至15任一项所述的制备方法制备的集流体。
  17. 一种电池模块，其特征在于，包括权利要求16所述的二次电池。
  18. 一种电池包，其特征在于，包括权利要求17所述的电池模块。
  19. 一种用电装置，其特征在于，包括选自权利要求16所述的二次电池、权利要求17所述的电池模块或权利要求18所述的电池包中的至少一种。
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