WO2023071045A1 - 集流体、电极片、电极组件、电池单体、电池和用电装置 - Google Patents

集流体、电极片、电极组件、电池单体、电池和用电装置 Download PDF

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Publication number
WO2023071045A1
WO2023071045A1 PCT/CN2022/083779 CN2022083779W WO2023071045A1 WO 2023071045 A1 WO2023071045 A1 WO 2023071045A1 CN 2022083779 W CN2022083779 W CN 2022083779W WO 2023071045 A1 WO2023071045 A1 WO 2023071045A1
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WO
WIPO (PCT)
Prior art keywords
layer
conductive layer
current collector
battery
battery cell
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2022/083779
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English (en)
French (fr)
Inventor
李兴星
陈智明
黄小腾
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Publication date
Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to JP2022532686A priority Critical patent/JP7522193B2/ja
Priority to KR1020227018613A priority patent/KR102880502B1/ko
Priority to EP22726253.2A priority patent/EP4195332A4/en
Priority to US18/123,366 priority patent/US20240039000A1/en
Publication of WO2023071045A1 publication Critical patent/WO2023071045A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • H01M4/665—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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • 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
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
    • 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
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • 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
    • 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
    • H01M50/249—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for aircraft or vehicles, e.g. cars or trains
    • 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
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/574—Devices or arrangements for the interruption of current
    • H01M50/581—Devices or arrangements for the interruption of current in response to temperature
    • 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

  • the present application relates to the field of battery technology, and in particular to a current collector, an electrode sheet, an electrode assembly, a battery cell, a battery and an electrical device.
  • the present application aims to provide a collector, an electrode sheet, an electrode assembly, a battery cell, a battery and an electrical device with higher safety performance.
  • the current collector provided by the present application includes:
  • the conductive layer is arranged on at least one of the opposite sides of the support layer, and when the support layer is heated and shrinks, it shrinks together with the support layer to form holes around the heated part, and the conductive layer includes a first conductive layer in contact with the support layer , the first conductive layer is a granular conductive layer.
  • the current collector can quickly cut off the failure circuit and prevent thermal runaway, so the safety performance can be effectively improved.
  • the granular conductive layer includes a layer of metal particles. Based on this, the current collector can have good electrical conductivity.
  • the metal particle layer includes a copper particle layer, an aluminum particle layer, a gold particle layer, a silver particle layer or an alloy particle layer. In this way, the electrical conductivity of the current collector can be effectively improved.
  • the resistivity of the alloy in the layer of alloy particles is less than or equal to 30 ⁇ 10 ⁇ 9 ⁇ m. In this way, the current collector can have better electrical conductivity.
  • the first conductive layer is sprayed on the support layer. Based on this, the granular conductive layer can be conveniently compounded on the support layer, and after spraying, the granular conductive layer can be relatively firmly attached to the support layer.
  • the conductive layer includes a second conductive layer electrically connected to the surface of the granular conductive layer facing away from the support layer. Based on this, the conductivity of the conductive layer can be enhanced.
  • the second conductive layer is bonded to the first conductive layer. Based on this, the connection between the first conductive layer and the second conductive layer is convenient, and the connection is strong, and at the same time, it is convenient to realize the electrical connection relationship between the two.
  • the second conductive layer includes a graphite layer. Based on this, the conductive performance of the conductive layer can be improved more effectively.
  • the conductivity of the conductive layer is 10 4 -10 5 S/cm.
  • the conductive layer can better meet the conductive requirements of the current collector, and can effectively prevent the excessive heat generation of the battery cell during the normal charging and discharging process.
  • the melting point of the support layer is less than or equal to 120°. Based on this, the support layer is more likely to melt and shrink before other parts are melted, cutting off the failure circuit, so it can more reliably prevent thermal runaway and improve safety performance more effectively.
  • the support layer is a support membrane.
  • the current collector not only has better safety performance, but also has stronger structural stability.
  • the support layer is made of polymer organic material.
  • the support layer made of high molecular organic material can quickly cut off the failure circuit when needed, prevent thermal runaway and improve safety performance.
  • the support layer is a polyethylene film.
  • the polyethylene film can not only effectively prevent thermal runaway, but also enhance the bending resistance of the current collector.
  • the electrode sheet provided by the present application includes an active material, and further includes the current collector of the embodiment of the present application, and the active material is disposed on the surface of the current collector.
  • the safety performance of the electrode sheet is higher.
  • the electrode assembly provided by this application includes:
  • the positive electrode sheet and/or the negative electrode sheet are the electrode sheets of the embodiment of the present application.
  • the safety performance of the electrode assembly is higher.
  • the battery cell provided in this application includes a casing, and also includes the electrode assembly of the embodiment of the application, and the electrode assembly is arranged in the casing.
  • the safety performance of the battery cell is higher.
  • the battery provided in the present application includes a storage box, and further includes the battery cell according to the embodiment of the application, and the battery cell is arranged in the storage box.
  • the safety performance of the battery is higher.
  • the electric device provided by the present application includes the battery or the battery cell according to the embodiment of the present application, and the battery cell is used to provide electric energy for the electric device.
  • the safety performance of the electrical device is higher.
  • the support layer when a short circuit occurs during the operation of the battery cell, the support layer can be affected by the high temperature at the failure point, melt and shrink, and drive the conductive layer to shrink together, forming holes around the heated part , to block the failure circuit and prevent the occurrence of thermal runaway, and, because the conductive layer includes a granular conductive layer, compared with other forms of conductive layers, the granular conductive layer is easier to shrink with the support layer when the support layer is heated. Therefore, when a short circuit accident occurs, the circuit can be blocked more quickly and thermal runaway can be prevented in a timely manner, so the safety performance of the battery can be improved more effectively.
  • FIG. 1 is a schematic structural diagram of an electrical device in an embodiment of the present application.
  • FIG. 2 is a schematic diagram of an explosion of a battery in an embodiment of the present application.
  • FIG. 3 is a schematic diagram of an explosion of a battery cell in an embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of an electrode assembly in an embodiment of the present application.
  • Fig. 5 is a schematic diagram of the structure of the current collector in the embodiment of the present application.
  • FIG. 6 is a schematic diagram of the principle of preventing thermal runaway of the current collector in the embodiment of the present application.
  • Electrode terminal 20. Battery cell; 201. Electrode assembly; 202. Shell; 203. Shell; 204. End cap; 205. Adapter; 206. Electrode terminal;
  • Storage box 301. Box body; 302. Box cover;
  • a short circuit trigger 71.
  • a puncture needle 71.
  • orientation words such as “front, back, up, down, left, right", “horizontal, vertical, vertical, horizontal” and “top, bottom” etc. indicate the orientation Or positional relationship is generally based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description. In the absence of a contrary statement, these orientation words do not indicate or imply the device or element referred to It must have a specific orientation or be constructed and operated in a specific orientation, so it should not be construed as limiting the protection scope of the present application; the orientation words “inner and outer” refer to the inner and outer relative to the outline of each component itself.
  • Batteries are not only used in energy storage power systems such as hydropower, firepower, wind power 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 battery applications, the requirements for its performance are also increasing.
  • safety performance is an important performance index of the battery. During the use of batteries and routine maintenance, it is necessary to prevent thermal runaway accidents. How to more effectively prevent thermal runaway and improve safety performance has always been a difficult problem.
  • the present application provides a current collector, an electrode assembly, a battery cell, a battery and an electrical device.
  • Figures 1-6 show the structures of electrical devices, batteries, battery cells, electrode assemblies and current collectors in some embodiments of the present application.
  • FIG. 1 exemplarily shows the structure of an electrical device 100 .
  • an electric device 100 is a device that uses a battery cell 20 as a power source, and includes a battery 10 or a battery cell 20 , and the battery cell 20 is used to provide electric energy for the electric device 100 .
  • the electrical device 100 includes a body 105 and a battery cell 20 , and the battery cell 20 is disposed on the body 105 and provides electric energy for the body 105 .
  • the electric device 100 may be various electric devices such as mobile phones, tablets, notebook computers, electric toys, electric tools, battery cars, electric vehicles, ships, and spacecraft.
  • electric toys may include stationary or mobile electric toys, for example, game consoles, electric car toys, electric boat toys, electric airplane toys, and the like.
  • Spacecraft may include airplanes, rockets, space shuttles, and spaceships, among others.
  • the electric device 100 includes a power source, and the power source includes a battery 10 , and the battery 10 provides driving force for the electric device 100 .
  • the driving force of the electric device 100 is all electric energy, and at this time, the power source only includes the battery 10 .
  • the driving force of the electric device 100 includes electric energy and other energy sources (such as mechanical energy), and at this time, the power source includes other devices such as the battery 10 and the engine.
  • the electrical device 100 is a vehicle 101 as an example.
  • the electrical device 100 is a new energy vehicle such as a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, which includes a battery 10, a controller 102, and a motor 104 and other power equipment 103.
  • the battery 10 is controlled by The battery 102 is electrically connected to the power equipment 103 such as the motor 104 , so that the battery 10 can supply power for the power equipment 103 such as the motor 104 under the control of the controller 102 .
  • the battery 10 is an important part of the electrical device 100 .
  • FIG. 2 exemplarily shows the structure of the battery 10 .
  • the battery 10 includes a storage box 30 and a battery cell 20 disposed in the storage box 30 .
  • the storage box 30 includes a box body 301 and a box cover 302 .
  • the box body 301 and the box cover 302 are fastened together, so that a closed accommodating space is formed inside the accommodating box 30 for accommodating the battery cells 20 .
  • the number of battery cells 20 in the storage box 30 can be at least two, so as to provide more electric energy and meet higher usage requirements.
  • the battery cells 20 of the battery 10 can be electrically connected in series, in parallel or in parallel to achieve greater capacity or power. It can be understood that, in FIG. 2 , a simplified drawing method is adopted for the battery cell 20 .
  • the battery cell 20 is the smallest battery unit for providing electric energy, which is the core component of the electric device 100 and the battery 10 , and its performance directly affects the performance of the electric device 100 and the battery 10 .
  • the improvement of the safety performance of the battery cell 20 is conducive to improving the performance of the electric device 100 and the battery 10 .
  • the battery cell 20 can be various types of battery cells such as lithium-ion batteries, and can be in various shapes such as square or cylindrical.
  • FIG. 3 exemplarily shows the structure of the battery cell 20 .
  • the battery cell 20 includes a casing 202 , an electrode assembly 201 , an adapter 205 , an electrode terminal 206 and a separator 208 .
  • the casing 202 is used to accommodate the electrode assembly 201 and the like, so as to provide protection for the electrode assembly 201 and the like.
  • the housing 202 includes a housing 203 and an end cap 204 .
  • the end cap 204 covers the end opening of the casing 203 , so that a closed space for accommodating the electrode assembly 201 and the like is formed inside the casing 202 .
  • the electrode assembly 201 is used to generate electric energy, which is disposed inside the shell 202 and provides electric energy by electrochemically reacting with the electrolyte injected into the shell 202 .
  • the number of electrode assemblies 201 in the battery cell 20 can be one, two, or more.
  • the electric energy generated by the electrode assembly 201 is transmitted to the outside through the tab 207 .
  • the tab 207 is the part of the positive and negative electrodes of the electrode assembly 201 that is not coated with the active material 6, which extends outward from the part of the positive and negative electrodes coated with the active material 6, and passes through the adapter 205 and the electrode terminal. 206. Electrically connect with an external circuit, so as to realize the outward transmission of electric energy.
  • the tab 207 of the positive electrode is called a positive tab
  • the tab 207 of the negative tab is called a negative tab.
  • the adapter 205 is disposed in the casing 202 and is located between the tab 207 of the electrode assembly 201 and the electrode terminal 206, for realizing the electrical connection between the electrode assembly 201 and the electrode terminal 206, so as to transfer the The electrical energy is delivered to the electrode terminals 206 .
  • the adapter 205 corresponding to the positive tab is called a positive adapter
  • the adapter 205 corresponding to the negative tab is called a negative adapter.
  • the electrode terminal 206 is electrically connected to the electrode assembly 201 through the adapter 205 , and is used for connecting with an external circuit, so as to transmit the electric energy generated by the electrode assembly 201 to the outside of the battery cell 20 .
  • the electrode terminal 206 corresponding to the positive tab is called a positive terminal
  • the electrode terminal 206 corresponding to the negative tab is called a negative terminal.
  • the separator 208 is disposed in the casing 202 and between the electrode assembly 201 and the casing 203 , and is used to insulate the electrode assembly 201 and the casing 203 to prevent a short circuit between the electrode assembly 201 and the casing 203 .
  • the electrode assembly 201 is an important part of the battery cell 20 and is the key to the battery cell 20 being able to provide electric energy.
  • FIG. 4 further shows the structure of the electrode assembly 201 .
  • the electrode assembly 201 includes electrode sheets 4 , and includes two kinds of electrode sheets 4 with opposite polarities, which are positive electrode sheet 1 and negative electrode sheet 2 .
  • the positive electrode sheet 1 and the negative electrode sheet 2 are stacked or wound together.
  • a separator 3 is provided between the positive electrode sheet 1 and the negative electrode sheet 2 , and the separator 3 separates the positive electrode sheet 1 and the negative electrode sheet 2 .
  • both the positive electrode sheet 1 and the negative electrode sheet 2 include an active material 6 and a current collector 5 .
  • the active material 6 is coated on the current collector 5 for electrochemical reaction with the electrolyte in the casing 202 to generate electric energy and realize the charging and discharging process.
  • the opposite sides of the current collector 5 are coated with active materials 6 .
  • the active materials 6 on the positive electrode sheet 1 and the negative electrode sheet 2 are different, so that the positive electrode sheet 1 and the negative electrode sheet 2 have opposite polarities.
  • the active material 6 on the positive electrode sheet 1 includes LiCoO2 (lithium-containing cobalt dioxide) particles
  • the active material 6 on the negative electrode sheet 2 includes SnO2 (tin dioxide) particles.
  • the current collector 5 not only plays the role of carrying the active material 6 , but also gathers the current generated by the electrochemical reaction to form a larger current and output it to the outside.
  • the current collector 5 is an integral part of the battery cell 20 and also an important factor affecting the safety of the battery cell 20 .
  • the current collector 5 is usually made of metal material.
  • the current collector 5 of the positive electrode sheet 1 is usually made of aluminum foil
  • the current collector 5 of the negative electrode sheet 2 is usually made of copper foil.
  • the metal material The current collector 5 is difficult to prevent thermal runaway when the battery cell 20 is short-circuited, which restricts the improvement of the safety performance of the battery cell 20 .
  • the thermal runaway of the battery cell 20 often originates from the violent chemical reaction or electrochemical reaction inside the battery cell 20 .
  • the diaphragm 3 in the battery cell 20 is damaged due to internal foreign matter (such as metal particles, burrs on the positive and negative electrodes, or metal lithium dendrites precipitated during battery use) or external punctures, the two sides of the damaged part Positive and negative plates may be turned on, and then a short circuit occurs.
  • the short circuit current will cause a sharp rise in temperature, trigger a more violent reaction, and spread to other parts, causing thermal runaway, resulting in fire or explosion accidents, which seriously threaten the personal safety of users.
  • the current collector 5 made of metal is not easy to melt, which leads to the fact that the current collector 5 has not yet melted when the short circuit occurs, and other components of the battery cell 20 (such as the active material 6 and the separator) 3) has already failed. In this case, the current collector 5 cannot prevent the current transfer, and thus cannot prevent the occurrence of thermal runaway. Therefore, the safety performance of the battery cell 20 is affected.
  • the present application improves the structure of the current collector 5 to improve the safety performance of the current collector 5 , the electrode assembly 201 , the battery cell 20 , the battery 10 and the electrical device 100 .
  • the current collector 5 provided by the embodiment of the present application includes a support layer 51 and a conductive layer 52 .
  • the conductive layer 52 is disposed on at least one of opposite sides of the support layer 51 , and when the support layer 51 is heated and shrinks, it shrinks together with the support layer 51 to form a hole 526 surrounding the heated portion.
  • the conductive layer 52 includes a first conductive layer 524 in contact with the support layer 51 , and the first conductive layer 524 is a granular conductive layer 521 .
  • the current collector 5 is no longer a single-layer metal foil structure, but becomes at least a two-layer structure including a support layer 51 and a conductive layer 52 .
  • the supporting layer 51 Since the supporting layer 51 has a low melting point, it can be melted when heated, and the conductive layer 52 is driven to shrink together, forming a hole 526 around the heated part. Therefore, when a short circuit occurs during the operation of the battery cell 20, the supporting layer 51 can be in the failure position. Under the action of the high temperature, the conductive layer 52 is driven to shrink together, forming a hole 526 around the failure point to block the failure circuit and prevent the occurrence of thermal runaway. Referring to Fig. 6, after the hole 526 is formed, there are no conductors around the short-circuit trigger 7 (for example, the puncture needle 71, metal particles or burrs) that caused the short-circuit accident, and the short-circuit trigger 7 can no longer be in contact with the conductor. Therefore, the circuit Disconnection can prevent the conduction between the positive electrode sheet 1 and the negative electrode sheet 2 due to the damage of the diaphragm 3, and can prevent local heat from continuing to spread to other parts, so thermal runaway can be prevented.
  • the first conductive layer 524 of the conductive layer 52 that is in contact with the supporting layer 51 is a granular conductive layer 521.
  • the supporting layer 51 shrinks together with the supporting layer 51 when heated, so that it is convenient to block the circuit more quickly and prevent thermal runaway in a timely manner when a short circuit accident occurs, so that the safety performance can be improved more effectively.
  • the current collector 5 configuring the current collector 5 to include a support layer 51 and a conductive layer 52, and configuring the first conductive layer 524 of the conductive layer 52 that is in contact with the support layer 51 as a granular conductive layer 521, it is possible to prevent heat more efficiently and reliably. Out of control, which can effectively improve the safety performance.
  • the granular conductive layer 521 may be composed of various metallic or non-metallic conductive particles.
  • the granular conductive layer 521 includes a metal granular layer 523 .
  • the granular conductive layer 521 includes the metal particle layer 523, it can effectively prevent thermal runaway while taking into account the electrical conductivity of the current collector 5, so that the current collector 5 has good electrical conductivity. , capable of conducting electricity efficiently in normal working conditions without short circuits.
  • the metal particle layer 523 includes a copper particle layer, an aluminum particle layer, a gold particle layer, a silver particle layer or an alloy particle layer.
  • Metal materials such as copper, aluminum, gold, silver or alloys are metal materials with good electrical conductivity, so the electrical conductivity of the current collector 5 can be effectively improved.
  • the resistivity of the alloy in the alloy particle layer is less than or equal to 30 ⁇ 10 -9 ⁇ m (ohm ⁇ meter), and the alloy particle layer at this time has higher conductivity efficiency, which can make the current collector 5 have better electrical conductivity.
  • the first conductive layer 524 can be sprayed on the support layer 51 .
  • the spraying method is more suitable for the granular state of the granular conductive layer 521 in the first conductive layer 524, and the granular conductive layer 521 can be easily compounded on the support layer 51, and after spraying, the granular conductive layer 521 can be relatively firm.
  • the conductive layer 52 not only includes the first conductive layer 524, but also includes the second conductive layer 525, and the second conductive layer 525 is electrically connected to the part of the granular conductive layer 521 that is away from the support layer 51. On the surface.
  • the second conductive layer 525 can further enhance the conductivity of the conductive layer 52 , further adding the second conductive layer 525 on the basis of the first conductive layer 524 can improve the conductivity of the current collector 5 more effectively.
  • the combination of the second conductive layer 525 and the first conductive layer 524 can be various.
  • the second conductive layer 525 can be bonded to the first conductive layer 524 , for example, the second conductive layer 525 can be bonded to the first conductive layer 524 through a conductive agent and an adhesive. Based on this, the connection between the first conductive layer 524 and the second conductive layer 525 is convenient, and the connection is strong, and at the same time, it is convenient to realize the electrical connection relationship between the two.
  • the structure of the second conductive layer 525 can be varied.
  • the second conductive layer 525 includes a graphite layer 522 . Since the conductivity of graphite is much higher than that of other non-metal conductive materials, setting the second conductive layer 525 to include the graphite layer 522 can more effectively improve the conductivity of the conductive layer 52 .
  • the conductivity of the conductive layer 52 is 10 4 -10 5 S/cm (Siemens per centimeter).
  • the conductive layer 52 can better meet the conductive requirements of the current collector 5 and can effectively prevent the battery cells 20 from generating excessive heat during normal charging and discharging.
  • the support layer 51 is used to support the conductive layer 52, and when a short circuit accident occurs, it drives the conductive layer 52 to shrink together, cut off the failure circuit, and prevent the occurrence of thermal runaway.
  • the melting point of the supporting layer 51 may be less than or equal to 120°. Based on this, the support layer 51 is more likely to melt and shrink before other parts are melted, cutting off the failure circuit, thus preventing thermal runaway more reliably and improving safety performance more effectively.
  • the supporting layer 51 is made of polymeric organic materials such as polyethylene, polypropylene or polyurethane.
  • Macromolecular organic materials such as polyethylene, polypropylene or polyurethane have a low melting point, and when locally heated, the heated part can shrink and collapse rapidly. Therefore, the support layer 51 made of macromolecular organic materials can be Quickly cut off the failure circuit to prevent thermal runaway and improve safety performance.
  • the shape of the supporting layer 51 can be various, for example, it can be granular or non-granular.
  • the support layer 51 is in the shape of a film, and in this case, the support layer 51 is a support film 511 .
  • the supporting film 511 can better support the conductive layer 52, so that the current collector 5 not only has better safety performance, but also has stronger structural stability.
  • the support layer 51 is a polyethylene film 512 .
  • the supporting layer 51 is a supporting film 511 made of polyethylene material, which can not only effectively prevent thermal runaway, but also enhance the bending resistance of the current collector 5 .
  • the current collector 5 includes a support layer 51 and two conductive layers 52, the two conductive layers 52 are arranged on opposite sides of the support layer 51, and each conductive layer 52 includes a second conductive layer 52.
  • a conductive layer 524 and a second conductive layer 525 are shown in FIG. 5, in this embodiment, the current collector 5 includes a support layer 51 and two conductive layers 52, the two conductive layers 52 are arranged on opposite sides of the support layer 51, and each conductive layer 52 includes a second conductive layer 52.
  • a conductive layer 524 and a second conductive layer 525 are examples of the current collector 524 and a second conductive layer 525 .
  • the supporting layer 51 is specifically a polyethylene film 512 .
  • the first conductive layer 524 is specifically the metal particle layer 523 .
  • the second conductive layer 525 is specifically the graphite layer 522 .
  • Polyethylene film 512 is in the middle. Both opposite sides of the polyethylene film 512 are spray-coated with metal particle layers 523 .
  • a graphite layer 522 is bonded to the outer surface of the metal particle layer 523 on each side.
  • the graphite layer 522 is bonded to the surface of the metal particle layer 523 facing away from the polyethylene film 512 through a conductive agent and an adhesive.
  • the surface of the graphite layer 522 facing away from the metal particle layer 523 becomes the outer surface of the conductive layer 52 for carrying the active material 6 .
  • the active material 6 is coated on the outer surface of the graphite layer 522 , so that the opposite sides of the current collector 5 are coated with the active material 6 .
  • the current collector 5 forms a five-layer structure with a polyethylene film 512 in the middle, and a metal particle layer 523 and a graphite layer 522 are symmetrically provided on both sides of the polyethylene film 512 .
  • the metal particle layer 523 and the graphite layer 522 mainly play a conductive role.
  • the conductive layer 52 composed of the metal particle layer 523 and the graphite layer 522 can maintain a conductivity within the range of 10 4 to 10 5 S/cm (Siemens per centimeter), which can better meet the conductivity requirements of the current collector 5 and effectively prevent Due to the high resistivity of the current collector 5 , the battery cell 20 generates too much heat during the normal charging and discharging process.
  • the polyethylene film 512 supports the metal particle layer 523 and the graphite layer 522 to enhance the bending resistance of the current collector 5 and improve the safety performance of the current collector 5 .
  • the metal particle layer 523 in FIG. 6 adopts a simplified drawing method.
  • the puncture needle 71 when the puncture needle 71 pierces the positive and negative electrode sheets and the separator 3, the puncture needle 71 conducts the current collector 5 of the positive electrode sheet 1 and the current collector 5 of the negative electrode sheet 2, and the failure point passes through
  • the current collector 5 is a metal current collector
  • the melting point of the metal current collector is higher than that of other materials, so other materials such as the active material 6 or the diaphragm 3 will be caused Component failure leads to thermal runaway, and the current collector 5 of this embodiment is no longer a single-layer metal foil structure, but a five-layer structure including a polyethylene film 512, a metal particle layer 523 and a graphite layer 522, wherein,
  • the part of the polyethylene film 512 used to support the metal particle layer 523 and the graphite layer 522 around the puncture needle 71 can rapidly melt and shrink during the temperature rise at the point of failure, driving the metal on the corresponding part of the polyethylene film 512.
  • the particle layer 523 and the graphite layer 522 shrink together, so that the part of the current collector 5 that is located around the puncture needle 71 collapses rapidly to form a hole 526, because the formed hole 526 can cut off the electrical connection between the puncture needle 71 and the current collector 5, and the circuit will fail. Cutting off, therefore, can effectively prevent the further development of the battery's internal electrochemical reaction and internal short circuit, and prevent thermal runaway, so it can effectively improve safety performance.
  • the metal particle layer 523 is granular, compared with non-granular situations such as metal foil, the bonding tightness between the metal particles is relatively low, and the metal particles are easily disconnected at high temperature. Therefore, when the polyethylene film 512 melts When shrinking, the metal particle layer 523 can easily shrink together, so that the current collector 5 can cut off the failure circuit more quickly, so it is beneficial to prevent thermal runaway more reliably, thereby improving safety performance more effectively.
  • the current collector 5 can be the current collector 5 of the positive electrode sheet 1 or the current collector 5 of the negative electrode sheet 2 .
  • the metal particle layer 523 may be an aluminum particle layer made of powdered aluminum powder.
  • the metal particle layer 523 may be a copper particle layer made of powdered copper powder.

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Abstract

本申请涉及电池技术领域，特别涉及一种集流体、电极片、电极组件、电池单体、电池和用电装置。集流体包括：支撑层；和导电层，设置于支撑层的相对两侧中的至少一侧，并在支撑层受热收缩时，随支撑层一起收缩，形成环绕受热部位的孔洞，导电层包括与支撑层接触的第一导电层，第一导电层为颗粒状导电层。基于此，可提升安全性能。

Description

集流体、电极片、电极组件、电池单体、电池和用电装置
相关申请的交叉引用
本申请是以申请号为202122614507.4，申请日为2021年10月28日的中国申请为基础，并主张其优先权，该中国申请的公开内容在此作为整体引入本申请中。
技术领域
本申请涉及电池技术领域，特别涉及一种集流体、电极片、电极组件、电池单体、电池和用电装置。
背景技术
随着电子产品以及电动车辆等用电装置的快速发展，电池的应用日益广泛。然而，电池较易短路，引发热失控，影响工作安全性。
发明内容
本申请旨在提供一种安全性能更高的集流体、电极片、电极组件、电池单体、电池和用电装置。
为了实现上述目的，本申请所提供的集流体，包括：
支撑层；和
导电层，设置于支撑层的相对两侧中的至少一侧，并在支撑层受热收缩时，随支撑层一起收缩，形成环绕受热部位的孔洞，导电层包括与支撑层接触的第一导电层，第一导电层为颗粒状导电层。
在支撑层和导电层的作用下，集流体可以快速切断失效电路，阻止热失控，因此，可以有效提升安全性能。
在一些实施例中，颗粒状导电层包括金属颗粒层。基于此，可以使得集流体具有良好的导电性能。
在一些实施例中，金属颗粒层包括铜颗粒层、铝颗粒层、金颗粒层、银颗粒层或合金颗粒层。这样，可以有效改善集流体的导电性能。
在一些实施例中，合金颗粒层中的合金的电阻率小于或等于30·10 -9Ω·m。这样， 可以使集流体具有较好的导电性能。
在一些实施例中，第一导电层喷涂于支撑层上。基于此，可以方便地将颗粒状导电层复合于支撑层上，且喷涂后，颗粒状导电层可以较为牢固地附着于支撑层上。
在一些实施例中，导电层包括第二导电层，第二导电层电连接于颗粒状导电层的背离支撑层的表面上。基于此，可以增强导电层的导电能力。
在一些实施例中，第二导电层粘接于第一导电层上。基于此，第一导电层和第二导电层之间连接方便，并且，连接牢固性较强，同时，方便实现二者之间的电连接关系。
在一些实施例中，第二导电层包括石墨层。基于此，可以更有效地提升导电层的导电性能。
在一些实施例中，导电层的导电率为10 4～10 5S/cm。此时，导电层能够更好地满足集流体的导电需求，可以有效防止电池单体在常规充放电过程中产热过大。
在一些实施例中，支撑层的熔点小于或等于120°。基于此，支撑层更容易在其他部分未熔化之前熔融收缩，切断失效电路，因此，能够更可靠地防止热失控，更有效地提升安全性能。
在一些实施例中，支撑层为支撑膜。此时，集流体不仅安全性能较好，而且结构稳定性较强。
在一些实施例中，支撑层由高分子有机材料制成。由高分子有机材料制成的支撑层，可以在需要时，快速切断失效电路，防止热失控，提升安全性能。
在一些实施例中，支撑层为聚乙烯膜。聚乙烯膜不仅可以有效防止热失控，而且可以增强集流体的抗弯折性。
本申请所提供的电极片，包括活性物质，并且还包括本申请实施例的集流体，活性物质设置于集流体的表面。
由于包括本申请实施例的集流体，因此，电极片的安全性能更高。
本申请所提供的电极组件，包括：
正极片；和
负极片；
其中，正极片和/或负极片为本申请实施例的电极片。
由于包括本申请实施例的集流体，因此，电极组件的安全性能更高。
本申请所提供的电池单体，包括外壳，并且还包括本申请实施例的电极组件，电 极组件设置于外壳中。
由于包括本申请实施例的集流体，因此，电池单体的安全性能更高。
本申请所提供的电池，包括容置箱，并且还包括本申请实施例的电池单体，电池单体设置于容置箱中。
由于包括本申请实施例的集流体，因此，电池的安全性能更高。
本申请所提供的用电装置，包括本申请实施例的电池或电池单体，电池单体用于为用电装置提供电能。
由于包括本申请实施例的集流体，因此，用电装置的安全性能更高。
基于本申请实施例所提供的集流体，当电池单体工作过程中发生短路时，支撑层可以受失效位置点高温的影响，而熔化收缩，并带动导电层一起收缩，形成环绕受热部位的孔洞，将失效电路阻断，防止热失控现象的发生，并且，由于导电层包括颗粒状导电层，与其他形态的导电层相比，颗粒状导电层更容易在支撑层受热收缩时随着支撑层一起收缩，因此，可以在短路事故发生时，更快速地将电路阻断，更及时地阻止热失控，所以，能够更有效地提升电池的安全性能。
通过以下参照附图对本申请的示例性实施例进行详细描述，本申请的其它特征及其优点将会变得清楚。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为本申请实施例中用电装置的结构简图。
图2为本申请实施例中电池的爆炸示意图。
图3为本申请实施例中电池单体的爆炸示意图。
图4为本申请实施例中电极组件的结构简图。
图5为本申请实施例中集流体的结构简图。
图6为本申请实施例中集流体防止热失控的原理示意图。
附图标记说明：
100、用电装置；101、车辆；102、控制器；103、动力设备；104、马达；105、本体；
10、电池；
20、电池单体；201、电极组件；202、外壳；203、壳体；204、端盖；205、转接件；206、电极端子；207、极耳；208、隔离件；
30、容置箱；301、箱体；302、箱盖；
1、正极片；
2、负极片；
3、隔膜；
4、电极片；
5、集流体；51、支撑层；511、支撑膜；512、聚乙烯膜；52、导电层；521、颗粒状导电层；522、石墨层；523、金属颗粒层；524、第一导电层；525、第二导电层；526、孔洞；
6、活性物质；
7、短路引发件；71、穿刺针。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本申请及其应用或使用的任何限制。基于本申请中的实施例，本领域普通技术人员在没有开展创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
对于相关领域普通技术人员已知的技术、方法和设备可能不作详细讨论，但在适当情况下，所述技术、方法和设备应当被视为说明书的一部分。
在本申请的描述中，需要理解的是，方位词如“前、后、上、下、左、右”、“横向、竖向、垂直、水平”和“顶、底”等所指示的方位或位置关系通常是基于附图所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，在未作相反说明的情况下，这些方位词并不指示和暗示所指的装置或元件必须具有特定的方位或者以特定的方位构造和操作，因此不能理解为对本申请保护范围的限制；方位词“内、外”是指相对于各部件本身的轮廓的内外。
在本申请的描述中，需要理解的是，使用“第一”、“第二”等词语来限定零部件，仅仅是为了便于对相应零部件进行区别，如没有另行声明，上述词语并没有特殊含义，因 此不能理解为对本申请保护范围的限制。
此外，下面所描述的本申请不同实施方式中所涉及的技术特征只要彼此之间未构成冲突就可以相互结合。
目前，电池的应用日益广泛。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。随着电池应用领域的不断扩大，对其性能的要求也在不断提高。
其中，安全性能是电池的重要性能指标。在电池的使用过程中，以及日常维护过程中，需要防止热失控事故的发生。而如何更有效地防止热失控，提升安全性能，一直是一个难题。
为了提升电池的安全性能，本申请提供了一种集流体、电极组件、电池单体、电池和用电装置。
图1-图6示出了本申请一些实施例中用电装置、电池、电池单体、电极组件和集流体的结构。
接下来即结合图1-图6对本申请予以说明。
图1示例性地示出了用电装置100的结构。参照图1，用电装置100是一种使用电池单体20作为电源的装置，其包括电池10或电池单体20，电池单体20用于为用电装置100提供电能。具体来说，用电装置100包括本体105和电池单体20，电池单体20设置于本体105上，并为本体105提供电能。
其中，用电装置100可以为手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等各种用电设备。其中，电动玩具可以包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等。航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
用电装置100包括动力源，动力源包括电池10，电池10为用电装置100提供驱动力。一些实施例中，用电装置100的驱动力全部为电能，此时，动力源仅包括电池10。另一些实施例中，用电装置100的驱动力包括电能和其他能源(例如机械能)，此时动力源包括电池10和发动机等其他设备。
以用电装置100为车辆101的情况为例。参见图1，一些实施例中，用电装置100为纯电动汽车、混合动力汽车或增程式汽车等新能源车，其包括电池10、控制器102以及马达 104等动力设备103，电池10通过控制器102与马达104等动力设备103电连接，使得电池10能在控制器102的控制下，为马达104等动力设备103供电。
可见，电池10是用电装置100的重要组成部分。
图2示例性地示出了电池10的结构。参见图2，电池10包括容置箱30和设置于容置箱30中的电池单体20。容置箱30包括箱体301和箱盖302。箱体301和箱盖302相互扣合，使得容置箱30内部形成封闭的容置空间，以容纳电池单体20。容置箱30中电池单体20的数量可以为至少两个，以提供更多的电能，满足更高的使用需求。电池10的各电池单体20可通过串联、并联或混联的方式电连接，以实现较大的容量或功率。可以理解，图2中对电池单体20采用了简化画法。
可见，电池单体20是用于提供电能的最小电池单元，其是用电装置100和电池10的核心组成部分，其性能直接影响用电装置100和电池10的性能。电池单体20安全性能的提升，有利于改善用电装置100和电池10的性能。
电池单体20可以为锂离子电池等各类电池单体，且形状可以为方形或圆柱形等各类形状。
图3示例性地示出了电池单体20的结构。参照图3，电池单体20包括外壳202、电极组件201、转接件205、电极端子206和隔离件208。
其中，外壳202用于容置电极组件201等，以为电极组件201等提供保护。外壳202包括壳体203和端盖204。端盖204盖合于壳体203的端部开口，使得外壳202内部形成用于容置电极组件201等的密闭空间。
电极组件201用于产生电能，其设置于外壳202内部，并通过与注入外壳202中的电解液进行电化学反应，而提供电能。根据实际使用需求，电池单体20中电极组件201的数量可以为一个，两个，或多个。电极组件201所产生的电能通过极耳207向外传递。
极耳207为电极组件201的正负极片的未涂覆活性物质6的部分，其由正负极片的涂覆有活性物质6的部分向外延伸，并通过转接件205和电极端子206，与外部电路电连接，以实现电能的向外传递。其中，正极片的极耳207称为正极耳，负极片的极耳207称为负极耳。
转接件205设置于外壳202中，并位于电极组件201的极耳207与电极端子206之间，用于实现电极组件201与电极端子206之间的电连接，以将电极组件201所产生的电能传递至电极端子206。其中，与正极耳相应的转接件205称为正转接件，与负极耳相应的转接件205称为负转接件。
电极端子206通过转接件205与电极组件201电连接，并用于与外部电路连接，以将电极组件201所产生的电能传递至电池单体20的外部。其中，与正极耳相应的电极端子206称为正极端子，与负极耳相应的电极端子206称为负极端子。
隔离件208设置于外壳202中，并位于电极组件201与壳体203之间，用于对电极组件201与壳体203进行绝缘，以防止电极组件201与壳体203之间发生短路。
可见，电极组件201是电池单体20的重要组成部分，是电池单体20能够提供电能的关键。
图4进一步示出了电极组件201的结构。参见图4，电极组件201包括电极片4，并且，包括两种极性相反的电极片4，分别为正极片1和负极片2。正极片1和负极片2堆叠或卷绕在一起。并且，正极片1和负极片2之间设有隔膜3，隔膜3对正极片1和负极片2进行分隔。
如图4所示，正极片1和负极片2均包括活性物质6和集流体5。活性物质6涂覆于集流体5上，用于与外壳202中的电解液发生电化学反应，以生产电能，实现充放电过程。由图4可知，一些实施例中，集流体5的相对两侧表面上均涂覆有活性物质6。
正极片1和负极片2上的活性物质6并不相同，使得正极片1和负极片2极性相反。例如，一些实施例中，正极片1上的活性物质6包括LiCoO2(含锂的二氧化钴)颗粒，负极片2上的活性物质6包括SnO2(二氧化锡)颗粒。
在电极组件201中，集流体5不仅起到承载活性物质6的作用，还起到将电化学反应所产生的电流汇集起来，形成较大的电流，对外输出的作用。集流体5是电池单体20的不可或缺的组成部分，也是影响电池单体20工作安全性的重要因素。
相关技术中，集流体5通常由金属材料制成，例如，正极片1的集流体5通常被制成铝箔，负极片2的集流体5通常被制成铜箔，然而，这种金属材质的集流体5，难以在电池单体20发生短路时阻止热失控，制约电池单体20安全性能的提升。
电池单体20的热失控往往源自于电池单体20内部剧烈的化学反应或电化学反应。当电池单体20中的隔膜3由于内部异物(如金属颗粒、正负极片上的毛刺或者电池使用过程中析出的金属锂枝晶等)或外部穿刺等原因而破损时，破损处两侧的正负极片可能被导通，进而发生短路现象。短路现象发生时，短路电流会造成温度急剧升高，引发更为剧烈的反应，并向其他部位扩散，引发热失控，导致起火或爆炸事故的发生，严重威胁使用者的人身安全。
由于金属材料的熔点较高，因此，金属材质的集流体5不易熔化，这就导致，当 短路现象发生时，集流体5尚未熔化，电池单体20的其他组成部分(例如活性物质6和隔膜3)就已经失效，这种情况下，集流体5无法阻挡电流传递，也就无法阻止热失控现象的发生，因此，影响电池单体20的安全性能。
针对上述情况，本申请对集流体5的结构进行改进，以提升集流体5、电极组件201、电池单体20、电池10和用电装置100的安全性能。
图5-图6示例性地示出了集流体5的结构。
参见图5和图6，本申请实施例所提供的集流体5包括支撑层51和导电层52。导电层52设置于支撑层51的相对两侧中的至少一侧，并在支撑层51受热收缩时，随支撑层51一起收缩，形成环绕受热部位的孔洞526。并且，导电层52包括与支撑层51接触的第一导电层524，第一导电层524为颗粒状导电层521。
可见，在本申请的实施例中，集流体5不再为单层金属箔结构，而是变为包括支撑层51和导电层52的至少两层结构。
由于支撑层51熔点较低，可以在受热时熔化，带动导电层52一起收缩，在受热部位四周形成孔洞526，因此，当电池单体20工作过程中发生短路时，支撑层51可以在失效位置点高温的作用下，通过带动导电层52一起收缩，在失效位置点四周形成孔洞526，来将失效电路阻断，防止热失控现象的发生。参见图6，当孔洞526形成后，引发短路事故发生的短路引发件7(例如穿刺针71、金属颗粒或毛刺)的四周不再有导体，短路引发件7无法再与导体接触，因此，电路断开，可以防止因隔膜3破损而导致正极片1和负极片2之间被导通，且可以防止局部热量继续向其他部位扩散，因此，可以防止热失控。
并且，由于在本申请的实施例中，导电层52的与支撑层51接触的第一导电层524为颗粒状导电层521，颗粒状导电层521与其他形态的导电结构相比，更容易在支撑层51受热收缩时随着支撑层51一起收缩，因此，方便在短路事故发生时，更快速地将电路阻断，更及时地阻止热失控，所以，能够更有效地提升安全性能。
可见，通过将集流体5构造为包括支撑层51和导电层52，并将导电层52的与支撑层51接触的第一导电层524构造为颗粒状导电层521，可以更加高效可靠地阻止热失控，从而可以实现对安全性能的有效提升。
其中，颗粒状导电层521可以由各种金属或非金属的导电颗粒组成。示例性地，参见图5，颗粒状导电层521包括金属颗粒层523。
由于金属具有较好的导电性能，因此，当颗粒状导电层521包括金属颗粒层523 时，可以在有效防止热失控的同时，兼顾集流体5的导电性能，使得集流体5具有良好的导电性能，能够在没有短路的正常工作状态中高效导电。
作为金属颗粒层523的示例，金属颗粒层523包括铜颗粒层、铝颗粒层、金颗粒层、银颗粒层或合金颗粒层。铜、铝、金、银或合金等金属材料，均为导电性能较好的金属材料，因此，可以有效改善集流体5的导电性能。
一些实施例中，合金颗粒层中的合金的电阻率小于或等于30·10 -9Ω·m(欧姆·米)，此时的合金颗粒层导电效率更高，可以使集流体5具有较好的导电性能。
第一导电层524与支撑层51之间的结合方式可以有多种。作为其中的一种，第一导电层524可以喷涂于支撑层51上。
采用喷涂方式，更适应第一导电层524中颗粒状导电层521的颗粒状状态，可以方便地将颗粒状导电层521复合于支撑层51上，且喷涂后，颗粒状导电层521可以较为牢固地附着于支撑层51上，一方面方便支撑层51在局部熔化时带动颗粒状导电层521一起熔断收缩，使得集流体5能够在短路事故发生时顺利切断电路，另一方面也有利于防止颗粒状导电层521在非短路状态时意外脱落，使得集流体5在正常工作过程中能够较为可靠地汇集并传递电流。
另外，参见图5，一些实施例中，导电层52不仅包括第一导电层524，同时还包括第二导电层525，第二导电层525电连接于颗粒状导电层521的背离支撑层51的表面上。
由于第二导电层525可以进一步增强导电层52的导电能力，因此，在第一导电层524的基础上，进一步增设第二导电层525，可以更有效地提升集流体5的导电能力。
其中，第二导电层525与第一导电层524之间的结合方式可以多样。作为其中的一种，第二导电层525可以粘接于第一导电层524上，例如，第二导电层525可以通过导电剂和胶粘剂粘接于第一导电层524上。基于此，第一导电层524和第二导电层525之间连接方便，并且，连接牢固性较强，同时，方便实现二者之间的电连接关系。
另外，第二导电层525的结构形式可以多样。例如，参见图5，一些实施例中，第二导电层525包括石墨层522。由于石墨比其他非金属导电材料的导电性高很多，因此，将第二导电层525设置为包括石墨层522，可以更有效地提升导电层52的导电性能。
一些实施例中，导电层52的导电率为10 4～10 5S/cm(西门子每厘米)。这种情况下，导电层52能够更好地满足集流体5的导电需求，可以有效防止电池单体20在常规充放电过程中产热过大。
在前述各实施例中，支撑层51用于支撑导电层52，并在短路事故发生时，带动导电层52一起收缩，切断失效电路，阻止热失控现象的发生。
其中，支撑层51的熔点可以小于或等于120°。基于此，支撑层51更容易在其他部分未熔化之前熔融收缩，切断失效电路，因此，能够更可靠地防止热失控，更有效地提升安全性能。
一些实施例中，支撑层51由聚乙烯、聚丙烯或聚氨酯等高分子有机材料制成。聚乙烯、聚丙烯或聚氨酯等高分子有机材料具有熔点较低，且局部受热时，受热部位能够迅速收缩坍塌的特点，因此，由高分子有机材料制成的支撑层51，可以在需要时，快速切断失效电路，防止热失控，提升安全性能。
另外，支撑层51的形状可以多样，例如，可以呈颗粒状，或非颗粒状。示例性地，参见图5，支撑层51呈膜状，此时，支撑层51为支撑膜511。支撑膜511可以较好地支撑导电层52，使得集流体5不仅安全性能较好，而且结构稳定性较强。
继续参见图5，一些实施例中，支撑层51为聚乙烯膜512。此时，支撑层51为由聚乙烯材料制成的支撑膜511，不仅可以有效防止热失控，而且可以增强集流体5的抗弯折性。
接下来对图5所示的实施例予以进一步地说明。
如图5所示，在该实施例中，集流体5包括支撑层51和两个导电层52，两个导电层52设置于支撑层51的相对两侧，且每个导电层52均包括第一导电层524和第二导电层525。
其中，支撑层51具体为聚乙烯膜512。第一导电层524具体为金属颗粒层523。第二导电层525具体为石墨层522。
聚乙烯膜512位于中间。聚乙烯膜512的相对两侧表面均喷涂有金属颗粒层523。每一侧的金属颗粒层523的外表面上均粘接有石墨层522。石墨层522通过导电剂和胶粘剂粘接于金属颗粒层523的背离聚乙烯膜512的表面上。石墨层522的背离金属颗粒层523的表面成为导电层52的外表面，用于承载活性物质6。在制作电极片4时，活性物质6涂覆于石墨层522的外表面上，使得集流体5的相对两侧表面均涂覆有活性物质6。
基于上述设置，集流体5形成中间为聚乙烯膜512，且聚乙烯膜512两侧对称设有金属颗粒层523和石墨层522的五层结构。
其中，金属颗粒层523和石墨层522主要起导电作用。金属颗粒层523和石墨层522所组成的导电层52，导电率可维持在10 4～10 5S/cm(西门子每厘米)范围内，可以较好地 满足集流体5的导电需求，有效防止电池单体20因集流体5电阻率较大而在常规充放电过程中产热过多。
聚乙烯膜512支撑金属颗粒层523和石墨层522，增强集流体5的抗弯折特性，并提升集流体5的安全性能。
以图6所示的穿刺失效的情况为例，说明该实施例集流体5的安全性能是如何提升的。图6中金属颗粒层523采用了简化画法。
参见图6，并结合图4，当穿刺针71刺穿正负极片和隔膜3时，穿刺针71将正极片1的集流体5和负极片2的集流体5导通，失效位置点通过极大电流，导致失效点温度极高，这种情况下，若集流体5为金属集流体，则由于金属集流体的熔点比其他材料要高，因此，会造成活性物质6或隔膜3等其他部件失效，导致热失控，而该实施例的集流体5，不再为单层金属箔结构，而是变为包括聚乙烯膜512、金属颗粒层523和石墨层522的五层结构，其中，用于支撑金属颗粒层523和石墨层522的聚乙烯膜512的位于穿刺针71四周的部分可以在失效位置点温度升高过程中，迅速熔融收缩，带动位于聚乙烯膜512相应部分上的金属颗粒层523和石墨层522一起收缩，使得集流体5的位于穿刺针71四周的部分迅速坍塌形成孔洞526，由于所形成的孔洞526可以切断穿刺针71与集流体5的电连接，将失效电路切断，因此，可以有效阻止电池内部电化学反应及内短路的进一步发展，防止热失控，所以，可以有效提升安全性能。
由于金属颗粒层523呈颗粒状，与金属箔等非颗粒状的情况相比，金属颗粒之间的结合紧密性相对较低，金属颗粒之间容易高温断开，因此，在聚乙烯膜512熔融收缩时，金属颗粒层523可以较为容易地随之一起收缩，方便集流体5更加迅速地切断失效电路，所以，有利于更可靠地防止热失控，从而更有效地提升安全性能。
其中，集流体5既可以为正极片1的集流体5，也可以为负极片2的集流体5。当集流体5为正极片1的集流体5时，金属颗粒层523可以为由粉末状的铝粉制成的铝颗粒层。当集流体5为负极片2的集流体5时，金属颗粒层523可以为由粉末状的铜粉制成的铜颗粒层。
以上所述仅为本申请的示例性实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。

Claims (12)

  1. 一种集流体(5)，包括：
    支撑层(51)；和
    导电层(52)，设置于所述支撑层(51)的相对两侧中的至少一侧，并在所述支撑层(51)受热收缩时，随所述支撑层(51)一起收缩，形成环绕受热部位的孔洞(526)，所述导电层(52)包括与所述支撑层(51)接触的第一导电层(524)，所述第一导电层(524)为颗粒状导电层(521)。
  2. 根据权利要求1所述的集流体(5)，其中，所述导电层(52)被构造为以下至少之一：
    所述颗粒状导电层(521)包括金属颗粒层(523)；
    所述导电层(52)包括第二导电层(525)，所述第二导电层(525)电连接于所述颗粒状导电层(521)的背离所述支撑层(51)的表面上；
    所述导电层(52)的导电率为10 4～10 5S/cm；
    所述第一导电层(524)喷涂于所述支撑层(51)上。
  3. 根据权利要求2所述的集流体(5)，其中，所述金属颗粒层(523)包括铜颗粒层、铝颗粒层、金颗粒层、银颗粒层或合金颗粒层。
  4. 根据权利要求3所述的集流体(5)，其中，所述合金颗粒层中的合金的电阻率小于或等于30·10 -9Ω·m。
  5. 根据权利要求2-4任一所述的集流体(5)，其中，所述第二导电层(525)粘接于所述第一导电层(524)上；和/或，所述第二导电层(525)包括石墨层(522)。
  6. 根据权利要求1-5任一所述的集流体(5)，其中，所述支撑层(51)被构造为以下至少之一：
    所述支撑层(51)的熔点小于或等于120°；
    所述支撑层(51)为支撑膜(511)；
    所述支撑层(51)由高分子有机材料制成。
  7. 根据权利要求6所述的集流体(5)，其中，所述支撑层(51)为聚乙烯膜(512)。
  8. 一种电极片(4)，包括活性物质(6)，并且还包括如权利要求1-7任一所述的集流体(5)，所述活性物质(6)设置于所述集流体(5)的表面。
  9. 一种电极组件(201)，包括：
    正极片(1)；和
    负极片(2)；
    其中，所述正极片(1)和/或所述负极片(2)为如权利要求8所述的电极片(4)。
  10. 一种电池单体(20)，包括外壳(202)，并且还包括如权利要求9所述的电极组件(201)，所述电极组件(201)设置于所述外壳(202)中。
  11. 一种电池(10)，包括容置箱(30)，并且还包括如权利要求10所述的电池单体(20)，所述电池单体(20)设置于所述容置箱(30)中。
  12. 一种用电装置(100)，包括如权利要求11所述的电池(10)或如权利要求10所述的电池单体(20)，所述电池单体(20)用于为所述用电装置(100)提供电能。
PCT/CN2022/083779 2021-10-28 2022-03-29 集流体、电极片、电极组件、电池单体、电池和用电装置 Ceased WO2023071045A1 (zh)

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CN216120659U (zh) 2022-03-22
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