WO2024011540A1 - Plaque d'électrode, batterie secondaire, module de batterie, bloc-batterie et dispositif électrique - Google Patents

Plaque d'électrode, batterie secondaire, module de batterie, bloc-batterie et dispositif électrique Download PDF

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Publication number
WO2024011540A1
WO2024011540A1 PCT/CN2022/105826 CN2022105826W WO2024011540A1 WO 2024011540 A1 WO2024011540 A1 WO 2024011540A1 CN 2022105826 W CN2022105826 W CN 2022105826W WO 2024011540 A1 WO2024011540 A1 WO 2024011540A1
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protective coating
edge
electrode
lithium
secondary battery
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PCT/CN2022/105826
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English (en)
Chinese (zh)
Inventor
张翠平
韩昌隆
范朋
吴则利
黄磊
陈慧玲
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/105826 priority Critical patent/WO2024011540A1/fr
Publication of WO2024011540A1 publication Critical patent/WO2024011540A1/fr

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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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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 lithium batteries, and in particular to an electrode pole piece, a secondary battery, a battery module, a battery pack and an electrical device.
  • Lithium-ion secondary batteries have many advantages such as high specific energy density, long cycle life, high nominal voltage, low self-discharge rate, small size, and light weight. They are widely used in various fields, including electric bicycles, electric vehicles, and other fields.
  • This application was made in view of the above-mentioned issues, and its purpose is to provide an electrode pole piece that can improve the stability of secondary batteries operating under high-temperature conditions and extend their cycle life.
  • the present application provides an electrode pole piece, a secondary battery, a battery module, a battery pack and a power device.
  • the first aspect of this application provides an electrode pole piece, including:
  • a current collector includes a base material and a protective coating.
  • the base material includes a main body portion and a tab portion arranged along a first direction.
  • the tab portion has a first edge extending along a second direction, and the first direction intersects the second direction;
  • the protective coating is disposed on a portion of the surface of the main body portion to form a second edge extending in the second direction adjacent to the tab portion, and the protective coating extends in the first direction and forms a third edge extending in the second direction. ;as well as
  • An electrode active material layer is provided on the protective coating and at least part of the surface of the main body part,
  • the area A 1 of the pole portion defined by the second edge and the first edge, and the area A 2 of the protective coating defined by the second edge and the third edge satisfy: 0.05 ⁇ A 2 /A 1 ⁇ 6, optional ,0.1 ⁇ A 2 /A 1 ⁇ 5.
  • This application effectively reduces the probability that the base material in the protective coating area contacts and reacts with the electrolyte by arranging a protective coating on the area of the current collector substrate close to the pole lug, and reasonably limiting the area of the protective coating. At the same time, It ensures the heat dissipation efficiency of the electrode pole piece, improves the integrity of the substrate in the protective coating area, improves the stability of the secondary battery operation and extends its cycle life.
  • the first edge, the second edge and the third edge are substantially parallel to each other, and the distance L 1 between the second edge and the first edge and the distance L 2 between the second edge and the third edge satisfy: 0.05 ⁇ L 2 /L 1 ⁇ 6, optional, 0.1 ⁇ L 2 /L 1 ⁇ 5.
  • the above three edges are substantially parallel, so that the planar shape of the protective coating and the tab portion is substantially rectangular.
  • Such a solution can improve the convenience of manufacturing current collectors, and by limiting the reasonable value range of L 2 /L 1 , it can reduce the coating area of the protective coating while ensuring that the protective coating plays a protective role. , beneficially improving the energy density of secondary batteries.
  • the substrate is selected from aluminum foil or aluminum polymer composite substrate.
  • aluminum substrates such as aluminum foil or aluminum polymer composite substrates
  • aluminum is prone to chemical reactions with some substances in the electrolyte, such as certain electrolytes, and is corroded, especially at elevated temperatures, resulting in the substrate being corroded.
  • the protective coating includes a binder and a conductive agent.
  • the binder is selected from the group consisting of polyacrylic resin, PVDF and its copolymers, polyacrylonitrile, epoxy resin conductive glue, and phenolic resin conductive resin.
  • At least one of the glue, optionally, the conductive agent is selected from at least one of carbon black, graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, and graphene.
  • the conductive agent can ensure that the protective coating has good conductivity, and the adhesive can ensure the bonding strength between the protective coating and the substrate.
  • the electrode active material layer includes an active material, an electrode binder, and an electrode conductive agent.
  • the active material is selected from LiNix Co y N z M 1-xyz O 2 , LiMn 2 O 4 , Li 2 MnO 3 ⁇ (1-a) At least one of LiPO 2 and LiFePO 4 ;
  • the electrode binder is selected from polyacrylic resin, PVDF and its copolymers, polyacrylonitrile, and epoxy resin conductive adhesive , at least one of phenolic resin conductive glue;
  • the electrode conductive agent is selected from at least one of carbon black, graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, and graphene.
  • the thickness H 1 of the protective coating and the thickness H 2 of the substrate satisfy the relationship: H 2 /26 ⁇ H 1 ⁇ H 2 /2.6. Therefore, by setting a reasonable coating thickness of the protective coating, the heat dissipation effect of the pole piece can be improved while ensuring the protective effect and preventing holes or breaks in the substrate, and the total thickness of the pole piece can be reduced as much as possible to ensure Energy density of secondary batteries.
  • the protective coating includes a binder with a mass of W 1 and a conductive agent with a mass of W 2 , and the ratio B of W 1 to W 1 + W 2 satisfies the relationship: 0.05 ⁇ B ⁇ 0.5.
  • the thickness D 1 of the electrode active material layer and the thickness H 1 of the protective coating satisfy the relationship: D 1 /200 ⁇ H 1 ⁇ D 1 /30.
  • a second aspect of the application provides a secondary battery, including the electrode pole piece of the first aspect of the application, a separator, and an electrolyte.
  • the electrolyte includes a solvent and an electrolyte.
  • the electrolyte includes lithium hexafluorophosphate and lithium fluorine-containing sulfonyl imide.
  • the molar concentration C 1 of the lithium hexafluorophosphate salt is 0.1 mol/L ⁇ C 1 ⁇ 1 mol/L
  • the lithium fluorine-containing sulfonyl imide is optional.
  • the molar concentration C 2 is 0.5mol/L ⁇ C 2 ⁇ 1.5mol/L.
  • the fluorine-containing sulfonyl imide lithium salt can withstand high temperatures and is insoluble in water. Therefore, adding a certain amount of fluorine-containing sulfonyl imide lithium salt can improve the safety of the secondary battery to a certain extent.
  • the molar concentration C 1 of the lithium hexafluorophosphate salt and the molar concentration C 2 of the lithium fluorine-containing sulfonylimide satisfy: 0.6mol/L ⁇ C 1 +C 2 ⁇ 2mol/L, and 1 ⁇ C 2 /C 1 ⁇ 5. Therefore, by setting a reasonable proportion of lithium hexafluorophosphate and lithium fluorine-containing sulfonimide in the electrolyte, the ionic conductivity of the electrolyte can be ensured while the chemical stability and thermal stability of the electrolyte can be improved, thereby improving the safety performance of the battery.
  • the tab area A 1 , the protective coating area A 2 , the molar concentration C 1 of the lithium hexafluorophosphate salt, and the molar concentration C 2 of the lithium fluorine-containing sulfonylimide satisfy: C 2 /(10C 1 ) ⁇ A 2 /A 1 ⁇ C 2 /(2C 1 )+2.5.
  • Fluorine-containing lithium sulfonylimide easily reacts chemically with aluminum.
  • the electrolyte contains a certain molar concentration of lithium hexafluorophosphate and fluorine-containing lithium sulfonylimide, by setting the area of the protective coating so that it meets the requirements stipulated in this embodiment, it can be ensured that even if an aluminum substrate is used, Prevents the corrosion of aluminum by lithium fluorosulfonyl imide, thereby preventing pits or breakage on the surface of the substrate.
  • the fluorine-containing sulfonyl imide lithium salt includes a compound represented by Formula I,
  • R 1 is selected from any one of F atom and C1-C3 alkyl group substituted by F;
  • R 2 is selected from any one of F atoms and C1-C3 alkyl groups substituted by F,
  • R 1 is an F atom and R 2 is an F atom.
  • the selected fluorosulfonimide lithium salt compound has a high thermal decomposition temperature and good water resistance, which can effectively improve the safety of the secondary battery operation process, and the raw materials of the above compound are easy to produce. Obtain and manufacture convenience.
  • the electrolyte further includes an additive selected from the group consisting of vinylene carbonate, vinyl sulfate, lithium difluoroxaloborate, lithium difluorophosphate, lithium tetrafluoroborate, 1,3-propanesultone, At least one of lithium trifluoromethanesulfonate and lithium diacetate borate.
  • an additive selected from the group consisting of vinylene carbonate, vinyl sulfate, lithium difluoroxaloborate, lithium difluorophosphate, lithium tetrafluoroborate, 1,3-propanesultone, At least one of lithium trifluoromethanesulfonate and lithium diacetate borate.
  • a third aspect of the present application provides a battery module including the secondary battery of the second aspect of the present application.
  • a fourth aspect of the application provides a battery pack, including the battery module of the third aspect of the application.
  • a fifth aspect of the present application provides an electrical device, including at least one selected from the secondary battery of the second aspect of the present application, the battery module of the third aspect of the present application, or the battery pack of the fourth aspect of the present application. kind.
  • this application effectively reduces the probability that the base material in the protective coating area contacts and reacts with the electrolyte in a high-temperature environment, while ensuring The heat dissipation efficiency of the electrode plate improves the integrity of the substrate in the protective coating area, improves the stability of the secondary battery operation and extends its cycle life.
  • Figure 1 is a schematic structural diagram of an electrode pole piece according to an embodiment of the present application.
  • Figure 2 is a schematic diagram of the B-B section in Figure 1.
  • FIG. 3 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 4 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 3 .
  • FIG. 5 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 6 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 7 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 6 .
  • FIG. 8 is a schematic diagram of a power consumption device using a secondary battery as a power source according to an embodiment of the present application.
  • 6 electrode pole piece 61 current collector; 611 base material; 612 protective coating; 613 main body part; 614 pole ear part; 615 first edge; 616 second edge; 617 third edge; 62 electrode active material layer.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, 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, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • 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" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • a method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) can be added to the method in any order.
  • the method may include steps (a), (b) and (c), and may also include step (a). , (c) and (b), and may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: 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).
  • the preparation process of the electrode plate includes coating the active material slurry on the surface of the current collector substrate, and then cold pressing the current collector substrate coated with the active material slurry.
  • the cold pressing process can increase the compaction density of the active material layer, thereby increasing the energy density of the battery core.
  • it can enhance the contact between the active material and the substrate.
  • some active material particles will be pressed into the material of the current collector substrate, causing damage to the surface of the current collector substrate.
  • the surface of the damaged current collector base material comes into contact with the electrolyte, causing the materials inside the base material to be exposed to the electrolyte.
  • Certain substances in the electrolyte may react chemically with materials inside the substrate, especially when the battery is being charged and discharged. Such chemical reactions will cause corrosion pits or broken belts on the current collector substrate, creating safety risks and reducing the service life of the secondary battery.
  • the above-mentioned corrosion reaction is affected by temperature, and the reaction rate accelerates as the temperature increases.
  • the current generated by the active material of the electrode plate is collected into the tab through the current collector to be provided to the outside. Therefore, the temperature of the current collector near the pole ear is usually higher, and it is also the area where corrosion or breakage occurs most frequently.
  • this application has developed an electrode piece to address the above problems, which effectively reduces the probability that the base material in the protective coating area contacts and reacts with the electrolyte, while ensuring the heat dissipation efficiency of the electrode piece and improving the protective coating.
  • the integrity of the substrate in the area improves the operational stability of the secondary battery and extends its cycle life.
  • an electrode piece 6 is proposed. As shown in FIGS. 1 and 2 , the electrode piece 6 in this application includes a current collector 61 and an electrode active material layer 62 .
  • the current collector 61 includes a base material 611 and a protective coating 612.
  • the base material 611 includes a main body portion 613 and a tab portion 614 arranged along the first direction X.
  • the tab portion 614 has a first edge 615 extending along the second direction Y,
  • the first direction 612 expands along the first direction X and forms a third edge 617 extending along the second direction Y.
  • the electrode active material layer 62 is provided on the protective coating 612 and on at least part of the surface of the main body portion 613 .
  • the area A 1 of the pole portion 614 defined by the second edge 616 and the first edge 615 and the area A 2 of the protective coating 612 defined by the second edge 616 and the third edge 617 satisfy: 0.05 ⁇ A 2 /A 1 ⁇ 6, optional, 0.1 ⁇ A 2 /A 1 ⁇ 5.
  • the base material 611 can be divided into a main body part 613 and a tab part 614 according to functions.
  • the main part 613 is used to carry active materials in which electrochemical reactions will occur, and the tab parts 614 are used to draw out current. part.
  • the tab portion 614 is used to connect the tab, and no electrode active material is provided on the tab portion 614 .
  • the protective coating 612 is provided on the main body 613 , and the protective coating 612 covers part of the main body 613 .
  • the electrode active material layer 62 contains electrode active material and is a main component for electrochemical reactions. As shown in FIG. 1 , the electrode active material layer 62 is provided on the protective coating 612 and at least part of the surface of the main body portion 613 .
  • the protective coating 612 is used to protect the current collector substrate 611 from surface damage caused by the intrusion of active material particles.
  • the protective coating 612 is used to protect the current collector substrate 611 from surface damage caused by the intrusion of active material particles.
  • providing the protective coating 612 in the area of the main body 613 close to the tab portion 614 can effectively improve the gravimetric energy density of the secondary battery compared to coating the entire main body 613 with the protective coating 612.
  • the contact area between the electrode active material and the base material 611 is expanded, the internal impedance of the electrode is reduced, and the rate performance is improved.
  • coating a certain area of the protective coating on a specific area of the current collector substrate can protect the current collector substrate from breakage due to chemical corrosion without coating the entire area of the substrate.
  • the protective layer can improve the operational stability of the secondary battery and extend its cycle life, while also increasing the energy density of the electrode plate.
  • electrode active material layer 62 completely covers body portion 613 . As a result, the coating amount of the active material can be increased and the efficiency of the secondary battery can be improved.
  • the first edge 615, the second edge 616 and the third edge 617 are substantially parallel to each other, and the distance L 1 between the second edge 616 and the first edge 615 is the same as the distance L 1 between the second edge 616 and the third edge.
  • the spacing L 2 between 617 satisfies: 0.05 ⁇ L 2 /L 1 ⁇ 6, optional, 0.1 ⁇ L 2 /L 1 ⁇ 5.
  • the fact that the first edge 615, the second edge 616 and the third edge 617 are substantially parallel to each other means that the angle ⁇ ⁇ 3° formed by the intersection of the straight lines of any two edges. Therefore, the first edge 615 , the second edge 616 and the third edge 617 are substantially parallel, so that the planar shape of the protective coating 612 and the tab portion 614 is substantially rectangular.
  • Such a solution can improve the convenience of manufacturing the current collector 61, and by limiting the reasonable value range of L 2 /L 1 , it can ensure that the coating of the protective coating 612 plays a protective role while reducing the application cost of the protective coating 612. Coverage area, beneficially improve the energy density of secondary batteries.
  • the first direction X is perpendicular to the second direction Y.
  • the protective coating 612 is applied in a direction perpendicular to the edge and covers along the width direction of the tab portion 614, which can improve the protective performance of the protective coating 612 and prevent the base material 611 from breaking. At the same time, it can ensure the regularity of the shape of the protective coating 612 and improve the convenience of manufacturing and installation.
  • the substrate 611 is selected from aluminum foil or aluminum polymer composite substrates.
  • Aluminum has properties such as good electrical conductivity and flexibility, making it a good conductor of electricity and easy to process. Fresh aluminum foil is easily oxidized in the air, and then an oxide film will be formed on the surface. This oxide film can block the corrosion of aluminum by external moisture and air, further ensuring the thermodynamic stability of the aluminum foil. Therefore, aluminum is often used as a material for the positive electrode current collector of secondary batteries.
  • the active material particles will crush the protective oxide film on the surface of the aluminum foil, thus destroying the integrity of the oxide film, causing some Aluminum exposed. Because aluminum has strong reducing properties, it is prone to chemical reactions with certain substances in the electrolyte and is corroded.
  • the electrolyte contains a fluorine-containing sulfonyl imide lithium salt
  • the fluorine-containing sulfonyl imide lithium salt is oxidized, and the anions of the oxidation product react with the exposed fresh aluminum to form a product and Soluble in electrolyte.
  • the corrosion reaction is affected by temperature and accelerates as the temperature increases. Therefore, corrosion pits or broken strips will appear in the area of the current collector close to the tabs, causing safety risks and reducing the service life of the secondary battery.
  • the thickness of the substrate 611 ranges from 8 ⁇ m to 20 ⁇ m.
  • the energy density of the secondary battery can be improved while ensuring the conductive effect of the electrode plate.
  • the protective coating 612 includes a binder and a conductive agent.
  • the binder is selected from polyacrylic resin, PVDF and its copolymers, polyacrylonitrile, epoxy resin conductive glue, At least one of the phenolic resin conductive adhesives, optionally, the conductive agent is selected from at least one of carbon black, graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, and graphene.
  • the conductive agent can ensure that the protective coating 612 has good conductivity, and the adhesive can ensure the bonding strength between the protective coating 612 and the base material 611 .
  • the electrode active material layer 62 includes an active material, an electrode binder and an electrode conductive agent.
  • the active material is selected from LiNix Co y N z M 1-xyz O 2 , LiMn 2 O 4. At least one of Li 2 MnO 3 ⁇ (1-a) LiPO 2 and LiFePO 4 ;
  • the electrode binder is selected from polyacrylic resin, PVDF and its copolymers, polyacrylonitrile, and epoxy At least one of resin conductive glue and phenolic resin conductive glue; optionally, the electrode conductive agent is selected from at least one of carbon black, graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, and graphene.
  • the cathode active material in the embodiment of the present application can be selected from:
  • N is selected from Mn and Al
  • M is selected from Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, Any one of V and Ti, 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, x+y+z ⁇ 1,
  • Any one of them can also be a positive electrode material mixed with the above three types of materials in any proportion.
  • the negative active material in the embodiment of the present application can be selected from: natural graphite, artificial graphite, mesophase microcarbon balls (MCMB for short), hard carbon, soft carbon, silicon, silicon-carbon composite, Li- One or more of Sn alloy, Li-Sn-O alloy, Sn, SnO, SnO 2 , spinel structure lithiated TiO 2 -Li 4 Ti 5 O 12 , and Li-Al alloy.
  • MCMB mesophase microcarbon balls
  • the thickness H 1 of the protective coating 612 and the thickness H 2 of the substrate satisfy the relationship: H 2 /26 ⁇ H 1 ⁇ H 2 /2.6. Therefore, by setting a reasonable coating thickness of the protective coating 612, the heat dissipation effect of the pole piece can be improved while ensuring the protection effect and preventing the occurrence of holes or breaks in the base material 611, and the total thickness of the pole piece can be reduced as much as possible. , ensuring the energy density of secondary batteries.
  • the protective coating 612 includes a binder with a mass of W 1 and a conductive agent with a mass of W 2 .
  • the ratio B of W 1 to W 1 + W 2 satisfies the relationship: 0.05 ⁇ B ⁇ 0.5.
  • the thickness D 1 of the active material layer and the thickness H 1 of the protective coating satisfy the relationship: D 1 /200 ⁇ H 1 ⁇ D 1 /30.
  • the electrode pole pieces are prepared by the following method:
  • the preparation method of the above electrode pole piece is simple and has high manufacturability.
  • a second aspect of the application provides a secondary battery, including the electrode pole piece of the first aspect of the application, a separator, and an electrolyte.
  • the electrolyte includes a solvent and an electrolyte.
  • isolation membrane there is no particular restriction on the type of isolation membrane, and any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions.
  • the materials of each layer can be the same or different, and there is no particular limitation.
  • the positive electrode piece, the negative electrode piece and the isolation film can be made into an electrode assembly through a winding process or a lamination process.
  • the solvent is selected from at least two of dimethyl carbonate, diethyl carbonate, propylene carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethyl formate, ethyl acetate, and tetrahydrofuran. .
  • the solvent may also include dipropyl carbonate, methylpropyl carbonate, ethylene carbonate, propylene carbonate, ethylene carbonate, butylene carbonate, ethyl propyl carbonate, ⁇ -butyrolactone, methyl formate.
  • dipropyl carbonate methylpropyl carbonate
  • ethylene carbonate propylene carbonate
  • ethylene carbonate butylene carbonate
  • ethyl propyl carbonate methyl formate.
  • the mass percentage of the solvent in the electrolyte is 65% to 85%.
  • the electrolyte includes lithium hexafluorophosphate and fluorine-containing sulfonyl imide lithium salt.
  • the molar concentration C 1 of the lithium hexafluorophosphate salt is 0.1 mol/L ⁇ C 1 ⁇ 1 mol/L
  • the fluorine-containing sulfonyl imide lithium salt is The molar concentration C 2 of lithium amine is 0.5 mol/L ⁇ C 2 ⁇ 1.5 mol/L.
  • the fluorine-containing sulfonyl imide lithium salt can withstand high temperatures and is insoluble in water. By adding a certain amount of fluorine-containing sulfonyl imide lithium salt, the safety of the secondary battery can be improved to a certain extent.
  • the molar concentration C 1 of the lithium hexafluorophosphate salt and the molar concentration C 2 of the lithium fluorine-containing sulfonylimide satisfy: 0.6mol/L ⁇ C 1 +C 2 ⁇ 2mol/L, and 1 ⁇ C 2 /C 1 ⁇ 5.
  • the ionic conductivity of the electrolyte can be ensured while the chemical stability and thermal stability of the electrolyte can be improved, thereby improving the safety of the battery. performance.
  • the tab area A 1 , the protective coating area A 2 , the molar concentration C 1 of the lithium hexafluorophosphate salt, and the molar concentration C 2 of the fluorinated sulfonylimide lithium salt satisfy: C 2 /(10C 1 ) ⁇ A 2 /A 1 ⁇ C 2 /(2C 1 )+2.5.
  • Fluorine-containing lithium sulfonylimide easily reacts chemically with aluminum.
  • the electrolyte contains a certain molar concentration of lithium hexafluorophosphate and lithium fluorine-containing sulfonimide
  • the area of the protective coating so that it meets the requirements stipulated in this embodiment, it can be ensured that even if an aluminum substrate is used, It can prevent the corrosion of aluminum by lithium fluorosulfonyl imide, thus preventing pits or breakage on the surface of the substrate.
  • the fluorine-containing sulfonyl imide lithium salt includes compounds represented by formula I,
  • R 1 is selected from any one of F atom and C1-C3 alkyl group substituted by F;
  • R 2 is selected from any one of F atoms and C1-C3 alkyl groups substituted by F,
  • R 1 is an F atom and R 2 is an F atom.
  • the selected fluorosulfonimide lithium salt compound has a high thermal decomposition temperature and good water resistance, which can effectively improve the safety of the secondary battery operation process, and the raw materials of the above compound are easy to produce. Obtain and manufacture convenience.
  • the electrolyte further includes additives selected from the group consisting of vinylene carbonate, vinyl sulfate, lithium difluoroxalate borate, lithium difluorophosphate, lithium tetrafluoroborate, and 1,3-propanesulfonic acid. At least one of ester, lithium trifluoromethanesulfonate, and lithium diacetate borate.
  • FIG. 3 shows a square-structured secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.
  • FIG. 5 shows a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, it can also be arranged in any other way. Furthermore, the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical device.
  • the electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
  • FIG. 8 shows an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • the device may be a mobile phone, a tablet, a laptop, etc.
  • the device is usually required to be thin and light, and a secondary battery can be used as a power source.
  • LiNi 0.5 Co 0.2 Mn 0.3 O 2 LiNi 1/3 Co 1/3 Mn 1/3 O 2 , LiMnO 2 electrode conductive agent Super P, and electrode binder polyvinylidene fluoride (PVDF) in N -Cathode active slurry is made from methylpyrrolidone (NMP).
  • NMP methylpyrrolidone
  • the solid content of the cathode active slurry is 50wt%, and the mass ratio of LiNi 0.5 Co 0.2 Mn 0.3 O 2 , Super P, and PVDF in the solid component is 8:1: 1.
  • Example 1 0.5 0.5 145 84.50%
  • Example 2 0.8 1.0 140 85.60%
  • Example 3 1.0 2.0 151 86.30%
  • Example 4 2.5 2.5 150 86.70%
  • Example 5 2.0 2.5 146 86.80%
  • Example 6 2.5 4.5 150 83.30% Comparative example 1
  • No protective coating No protective coating 90 73.80% Comparative example 2
  • Example 3 4 5.5 121 73.20%
  • the positive electrode active slurry was prepared in N-methylpyrrolidone (NMP).
  • NMP N-methylpyrrolidone
  • the solid content of the positive electrode active slurry is 50wt%, and the mass ratio of LiNi 0.5 Co 0.2 Mn 0.3 O 2 , Super P, and PVDF in the solid content is 8:1:1.
  • the positive electrode active slurry is coated on the aluminum foil and dried at 85°C, then cold-pressed, then trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 85°C for 4 hours to make positive electrode sheets.
  • the solid content of the negative active slurry is 30wt%, and the mass ratio of graphite, Super P, CMC and adhesive styrene-butadiene rubber (SBR) in the solid components is 80:15:3:2.
  • the negative electrode active slurry is coated on the copper foil and dried at 85°C, then cold pressed, trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 120°C for 12 hours to make the negative electrode piece.
  • PE polyethylene film
  • the electrode assembly is obtained by winding, the tabs are welded, and the bare electrode is
  • the core is placed in the outer package, and the electrolyte prepared above is injected into the dried electrode assembly, followed by packaging, standing, formation, shaping, capacity testing, etc., to complete the preparation of the secondary battery (the thickness of the soft-pack battery is 4.0 mm , width 60mm, length 140mm).
  • the cells in the secondary battery will release temperature during operation, so this test tests the high temperature resistance of the secondary battery by simulating the high temperature environment in the use environment. Specifically, by testing the thermal runaway temperature of the secondary battery, the reaction between the aluminum foil in the electrode plate of the secondary battery and the fluorine-containing sulfonimide lithium salt in the electrolyte can be obtained.
  • the reaction efficiency is high, the faster the positive electrode piece breaks, the lower the thermal runaway temperature, and the worse the performance of the electrode piece.
  • the reaction efficiency is low, the slower the positive electrode piece breaks, the higher the thermal runaway temperature, and the better the performance of the electrode piece.
  • Example 1 Battery number Thermal runaway temperature °C M
  • Example 2 140 85.6%
  • Example 3 151 86.3%
  • Example 4 150 86.7%
  • Example 5 146 86.8%
  • Example 6 150 83.3% Comparative example 1 90 73.8% Comparative example 2 100 76.5%
  • the thermal runaway temperatures in the above-mentioned examples are all higher than 140 degrees Celsius.
  • the above-mentioned thermal runaway temperature is relatively high and meets the thermal runaway temperature requirements of secondary batteries.
  • the rate discharge capacity retention rates of the above embodiments are significantly improved compared with the comparative examples. It shows that the electrode pole pieces in the above embodiments can effectively improve the electrical performance of the battery core.
  • the area of the protective coating in Example 1 is smaller, so its thermal runaway temperature is lower.
  • the active material and the aluminum foil have good conductivity, so it has a high rate discharge capacity retention rate.
  • the protective coating area of Example 4 is larger than that of Example 1, Example 2 and Example 3. Therefore, it can better protect the area near the pole lug from high temperatures, and the thermal runaway temperature is higher. And the area of the protective layer is relatively reasonable, so it has a high rate discharge capacity retention rate.
  • the protective coating area of Example 5 is larger than the protective coating area of Example 1, Example 2 and Example 3. Therefore, it can better protect the area near the pole lug from high temperatures, and the thermal runaway temperature is higher. And the area of the protective layer is relatively reasonable, so it has a high rate discharge capacity retention rate.
  • Comparative Example 1 there is no protective coating.
  • the surface of the aluminum foil punctured by the active material particles reacts rapidly with the fluorine-containing lithium sulfonyl imide in the electrolyte, causing the aluminum foil to break and causing a short circuit inside the battery. Therefore, it is damaged at 90°C. That is, thermal runaway occurs, and its rate discharge capacity retention rate is low and its electrical performance is poor.
  • the protective coating area of Comparative Example 2 is smaller. Therefore, the area near the pole lug cannot be effectively protected, and the aluminum foil will still be corroded and fractured at a lower temperature. And its rate discharge capacity retention rate is lower than that of the above-mentioned embodiments.
  • Comparative Example 3 has the largest protective coating area. Therefore, the area near the pole lug can be protected to a certain extent. However, the protective coating area is too large and the electrode piece cannot effectively dissipate heat, causing the temperature of the pole piece surface to rise rapidly, and the area near the pole lug will still undergo relatively large heat dissipation. Violent corrosion. Therefore, its thermal runaway temperature is lower. Moreover, its rate discharge capacity retention rate is lower than that of the above-mentioned embodiments.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Secondary Cells (AREA)

Abstract

La présente demande concerne une plaque d'électrode, une batterie secondaire, un module de batterie, un bloc-batterie et un dispositif électrique. La plaque d'électrode comprend : un collecteur de courant, comprenant un matériau de base et un revêtement de protection, le matériau de base comprenant une partie corps principal et une partie languette disposée dans une première direction, la partie languette comportant un premier bord s'étendant dans une seconde direction, le revêtement de protection étant disposé sur au moins une partie de la surface de la partie corps principal pour former un deuxième bord adjacent à la partie languette et s'étendant dans la seconde direction, et le revêtement de protection s'étendant dans la première direction et formant un troisième bord s'étendant dans la seconde direction ; et une couche de matériau actif d'électrode disposée sur un côté du revêtement de protection opposé à la partie corps principal, une surface A1 de la partie languette définie par le deuxième bord et le premier bord, et une surface A2 du revêtement de protection définie par le deuxième bord et le troisième bord satisfaisant la relation suivante : 0,05 ≤ A2/A1 ≤ 6. La plaque d'électrode dans des modes de réalisation de la présente invention permet d'améliorer la stabilité de batteries secondaires fonctionnant dans des conditions de température élevée, et de prolonger la durée de vie de ces batteries.
PCT/CN2022/105826 2022-07-14 2022-07-14 Plaque d'électrode, batterie secondaire, module de batterie, bloc-batterie et dispositif électrique WO2024011540A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105359303A (zh) * 2013-07-01 2016-02-24 Nec能源元器件株式会社 非水电解质二次电池用的电极、制造该电极的方法、以及非水电解质二次电池
CN111180738A (zh) * 2019-06-28 2020-05-19 宁德时代新能源科技股份有限公司 一种电极极片和电化学装置
CN112234212A (zh) * 2020-10-14 2021-01-15 珠海冠宇动力电池有限公司 一种正极极片及包括该正极极片的锂离子电池
JP2022023106A (ja) * 2016-04-08 2022-02-07 株式会社Ｇｓユアサ 蓄電素子
CN114175306A (zh) * 2021-03-30 2022-03-11 宁德新能源科技有限公司 电化学装置和电子装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105359303A (zh) * 2013-07-01 2016-02-24 Nec能源元器件株式会社 非水电解质二次电池用的电极、制造该电极的方法、以及非水电解质二次电池
JP2022023106A (ja) * 2016-04-08 2022-02-07 株式会社Ｇｓユアサ 蓄電素子
CN111180738A (zh) * 2019-06-28 2020-05-19 宁德时代新能源科技股份有限公司 一种电极极片和电化学装置
CN112234212A (zh) * 2020-10-14 2021-01-15 珠海冠宇动力电池有限公司 一种正极极片及包括该正极极片的锂离子电池
CN114175306A (zh) * 2021-03-30 2022-03-11 宁德新能源科技有限公司 电化学装置和电子装置

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