WO2023216241A1 - 二次电池及其制备方法、电池模块、电池包和用电装置 - Google Patents

二次电池及其制备方法、电池模块、电池包和用电装置 Download PDF

Info

Publication number
WO2023216241A1
WO2023216241A1 PCT/CN2022/092739 CN2022092739W WO2023216241A1 WO 2023216241 A1 WO2023216241 A1 WO 2023216241A1 CN 2022092739 W CN2022092739 W CN 2022092739W WO 2023216241 A1 WO2023216241 A1 WO 2023216241A1
Authority
WO
WIPO (PCT)
Prior art keywords
negative electrode
positive electrode
secondary battery
current collector
area
Prior art date
Application number
PCT/CN2022/092739
Other languages
English (en)
French (fr)
Inventor
严青伟
王家政
董晓斌
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2022/092739 priority Critical patent/WO2023216241A1/zh
Priority to KR1020247004128A priority patent/KR20240027836A/ko
Priority to CN202280050304.1A priority patent/CN117652051A/zh
Priority to EP22938760.0A priority patent/EP4318726A1/en
Publication of WO2023216241A1 publication Critical patent/WO2023216241A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the technical field of lithium batteries, and in particular to a secondary battery and its preparation method, battery module, battery pack and electrical device.
  • lithium-ion batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • This application was made in view of the above-mentioned problems, and its object is to provide a secondary battery which has improved first efficiency, cycle performance, and storage performance.
  • the present application provides a secondary battery and its preparation method, battery module, battery pack and electrical device.
  • a first aspect of the present application provides a secondary battery, including a positive electrode piece and a negative electrode piece.
  • the positive electrode piece includes a positive electrode current collector and positive electrode film layers on both surfaces of the positive electrode current collector.
  • the negative electrode sheet includes a negative electrode current collector and negative electrode film layers on both surfaces of the negative electrode current collector.
  • the negative electrode film layer includes a reaction zone that is opposite to the positive electrode film layer and a reaction zone that is not opposite to the positive electrode film layer. a non-reactive zone, wherein a barrier layer is provided on the surface of the non-reactive zone.
  • this application sets a barrier layer in the non-reactive area.
  • the electrolyte cannot infiltrate it, blocking the diffusion of lithium ions in the reaction area to the non-reactive area. path, thereby improving the first efficiency, cycle performance and storage performance of secondary batteries.
  • the barrier layer is selected from a film or coating that cannot be wetted by the electrolyte;
  • the film includes one or more of polypropylene, polyethylene, polyester fiber, and polyvinyl chloride, optionally
  • the coating includes one or more of cast polypropylene, uniaxially stretched polypropylene, biaxially stretched polypropylene, polyethylene, polyester fiber and polyvinyl chloride, and further optionally includes polyethylene; the coating Including polyvinylidene fluoride, polytetrafluoroethylene, polyamide, polyimide, polymethylmethacrylate, polyurethane, polystyrene, polyacrylic acid, polyacrylamide, polyacrylonitrile and copolymers of the above substances One or several.
  • the thickness of the barrier layer ranges from 6 ⁇ m to 40 ⁇ m, optionally from 10 ⁇ m to 20 ⁇ m. When the thickness of the barrier layer is within the given range, it can ensure that the pole piece does not undergo major deformation and is fully compatible with the battery core.
  • the film is adhesive and has an adhesive force greater than 20 N/m.
  • the adhesive force of the film is within the given range, the film can be effectively applied to the surface of the non-reactive zone.
  • a separation area is provided along the width direction of the negative electrode sheet at an end of the non-reactive area of the negative electrode sheet close to the reaction area, and the barrier layer starts from the separation area and moves away from the separation area.
  • the reaction zone is set up.
  • the width of the spacer zone is between 5 mm and 50 mm, optionally between 10 mm and 15 mm.
  • the width of the spacer area is within the given range, it can better assist in setting the barrier layer, more effectively isolate the electrolyte without affecting the processing of the pole piece.
  • the depth of the spacer region is equal to the thickness of the negative electrode film layer.
  • the depth of the spacer area is equal to the thickness of the negative electrode film layer, it will prevent the electrolyte from infiltrating along the bottom negative electrode film layer into the non-reactive area, thereby preventing the lithium ions in the reaction area from diffusing to the non-reactive area, thus improving the performance of the secondary battery. efficiency, cycle performance and storage performance.
  • the distance between the side of the spacer area close to the reaction zone and the reaction zone is 1 mm to 10 mm, optionally 2 mm to 4 mm.
  • the first efficiency and cycle performance of the secondary battery can be further improved.
  • a second aspect of the application also provides a method for preparing a secondary battery, including the following steps:
  • step (2) includes the step of providing a barrier layer on the negative electrode piece
  • the secondary battery includes a positive electrode piece and a negative electrode piece.
  • the positive electrode piece includes a positive electrode current collector and positive electrode film layers on both surfaces of the positive electrode current collector.
  • the negative electrode piece includes a negative electrode current collector and a positive electrode film layer on both surfaces of the positive electrode current collector. Negative electrode film layers on both surfaces of the negative electrode current collector, the negative electrode film layer includes a reaction area arranged opposite to the positive electrode film layer and a non-reactive area not arranged opposite to the positive electrode film layer, in the non-reactive area A barrier layer is provided on the surface of the reaction zone.
  • the method of the present application uses a simple process to set a barrier layer on the non-reactive area of the negative electrode plate, thereby isolating the non-reactive area, blocking the diffusion of lithium ions in the reaction area to the non-reactive area, and thereby improving the first efficiency of the secondary battery. , cycle performance and storage performance.
  • the barrier layer is provided by a coating or pasting process, optionally, the barrier layer is provided by a pasting process.
  • a third aspect of the present application provides a battery module, including the secondary battery of the first aspect of the present application or a secondary battery prepared by the method of the second aspect of the present application.
  • a fourth aspect of the present application provides a battery pack, including the battery module of the third aspect of the present application.
  • a fifth aspect of the present application provides an electrical device, including a secondary battery selected from the first aspect of the present application or a secondary battery prepared by the method of the second aspect of the present application, a battery module of the third aspect of the present application, or a secondary battery of the present application. At least one of the battery packs of the fourth aspect is applied.
  • the battery modules, battery packs and electrical devices of the present application include the secondary battery of the present application, and thus have at least the same advantages as the secondary battery.
  • FIG. 1 is a schematic diagram of a wound cell of a secondary battery according to an embodiment of the present application.
  • FIG. 2 is an expanded schematic view of the negative electrode tab of the wound cell of the secondary battery according to one embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is an expanded schematic view of the negative electrode tab of the wound cell of a secondary battery according to another embodiment of the present application.
  • FIG. 4 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 4 .
  • Figure 6 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 7 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 8 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 7 .
  • FIG. 9 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.
  • 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, 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
  • the 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.
  • steps (c) means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), also It may include steps (a), (c) and (b), or 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 negative electrode piece In a wound or laminated battery cell, since the negative electrode piece must completely cover the positive electrode piece, the negative electrode piece must have a non-reactive area that does not participate in the direct deintercalation of lithium with the positive electrode piece.
  • the lithium ions of the positive electrode are preferentially embedded in the reaction area of the negative electrode, that is, the area opposite to the positive electrode.
  • the potential of the reaction area of the negative electrode gradually decreases, while the non-reactive area is always at a relatively low level. At this time, a potential difference is formed between the non-reactive zone and the reaction zone of the negative electrode plate.
  • the lithium ions in the reaction zone diffuse and embed in the non-reactive zone at a slow speed, while the lithium ions embedded in the non-reactive zone are embedded in the non-reactive zone. It is difficult to return to the positive electrode piece during the discharge process, which causes irreversible lithium loss of the positive electrode piece, ultimately leading to the deterioration of the first effect, cycle performance and storage performance of the battery cell.
  • This application sets a barrier layer in the non-reactive area of the negative electrode plate. During the charging and discharging process of the battery core, since the non-reactive area is isolated, the electrolyte cannot infiltrate it, blocking the diffusion of lithium ions in the reaction area to the non-reactive area. path, thereby improving the first efficiency, cycle performance and storage performance of secondary batteries.
  • the present application proposes a secondary battery, including a positive electrode piece and a negative electrode piece.
  • the positive electrode piece includes a positive electrode current collector and positive electrode film layers on both surfaces of the positive electrode current collector.
  • the negative electrode electrode The sheet includes a negative electrode current collector and negative electrode film layers on both surfaces of the negative electrode current collector.
  • the negative electrode film layer includes a reaction area arranged opposite to the positive electrode film layer and a non-reactive area not arranged opposite to the positive electrode film layer, wherein in the non-reactive area A barrier layer is provided on the surface of the area.
  • the applicant unexpectedly discovered that by arranging a barrier layer on the non-reactive area of the negative electrode piece, during the charging and discharging process of the battery core, since the non-reactive area is isolated, the electrolyte cannot separate it. Wetting blocks the diffusion path of lithium ions from the reaction area to the non-reaction area, reducing the irreversible lithium loss of the positive electrode, thus improving the first efficiency, cycle performance and storage performance of the secondary battery.
  • the positive electrode piece, the negative electrode piece and the isolation film are made into the battery core using a winding process.
  • the negative electrode piece includes a reaction area that is opposite to the positive electrode piece and a non-reaction area that is not opposite to the positive electrode piece.
  • the non-reaction area includes an empty roll non-reaction area and a finishing non-reaction area.
  • FIG. 2 is an unfolded schematic view of the negative electrode tab in the wound battery core shown in FIG. 1 .
  • the middle part of the negative electrode piece is the reaction area
  • one end of one side (A side) is the empty roll non-reaction area
  • one end of the other side (B side) is the finishing non-reaction area.
  • the non-reaction area Set up a barrier layer in the area.
  • the barrier layer is selected from a film or coating that cannot be wetted by the electrolyte;
  • the film includes one or more of polypropylene, polyethylene, polyester fiber, and polyvinyl chloride, optionally including cast polyethylene.
  • the coating includes polyvinylidene fluoride, polyvinyl chloride One or more of tetrafluoroethylene, polyamide, polyimide, polymethyl methacrylate, polyurethane, polystyrene, polyacrylic acid, polyacrylamide, polyacrylonitrile and copolymers of the above substances.
  • PE film Since polyethylene (PE) film has the advantages of being odorless, non-toxic, stable within -90°C to 100°C, resistant to acids and alkalis, organic solvents, low water absorption, and excellent electrical insulation properties, the film optionally includes PE film .
  • polyester fibers include polyethylene terephthalate and polybutylene terephthalate.
  • the thickness of the barrier layer ranges from 6 ⁇ m to 40 ⁇ m, optionally from 10 ⁇ m to 20 ⁇ m.
  • the thickness of the barrier layer needs to be controlled. A barrier layer that is too thin will easily be damaged, while a barrier layer that is too thick will cause the pole piece to deform. When the thickness of the barrier layer is within the given range, it can ensure that the pole piece does not undergo major deformation and is fully compatible with the battery core.
  • the film is tacky with an adhesion force greater than 20 N/m, optionally greater than 200 N/m, further optionally greater than 400 N/m.
  • the film has a certain viscosity, and the adhesive force is too small to closely adhere the film to the negative electrode film layer on the negative electrode piece, and is easily torn.
  • the adhesive force of the film is greater than 20N/m, and can The adhesive force of the selected film is greater than the cohesion between particles in the negative electrode film layer, and the film can be effectively applied to the surface of the non-reactive area.
  • single-sided adhesive or double-sided adhesive films can meet this application. Since the double-sided adhesive film has an increased thickness compared to the single-sided adhesive film, this will lead to greater deformation of the pole piece, so
  • the film is optionally a one-sided adhesive film.
  • a spacer region is provided along the width direction of the negative electrode piece at an end of the non-reactive region of the negative electrode piece close to the reaction region, and the barrier layer is provided starting from the spacer region and away from the reaction region.
  • the electrolyte can be prevented from infiltrating into the non-reactive area after injection, thereby preventing the lithium ions in the reaction area from diffusing to the non-reactive area, thereby further improving the secondary battery.
  • FIG. 3 is an expanded schematic view of the negative electrode tab of the wound cell of a secondary battery according to another embodiment of the present application.
  • the middle part of the negative electrode piece is the reaction area
  • one end of one side (A side) is the empty roll non-reaction area
  • one end of the other side (B side) is the finishing non-reaction area, where the non-reaction area is close to the reaction area
  • One end of the negative electrode plate is provided with a spacer along the width direction of the negative electrode piece, and the barrier layer is provided starting from the spacer and away from the reaction area. More specifically, the barrier layer is disposed on the bottom surface of the spacer region, the side of the spacer region close to the non-reactive region, and the non-reactive region away from the reaction region.
  • the width of the spacer region is 5mm-50mm, optionally 10mm-15mm.
  • the width of the interval area is too wide, which affects the processing performance of the pole piece, especially during the cold pressing stage, resulting in uneven compaction of the pole piece. If the width is too narrow, it will affect the non-reaction area film application process in the later stage, causing the film to be not tight and the electrolyte to penetrate from the bottom. When the width of the spacer area is within the given range, it can better assist in setting the barrier layer, more effectively isolate the electrolyte without affecting the processing of the pole piece.
  • the depth of the spacer region is equal to the thickness of the negative electrode film layer.
  • the depth of the separation area is less than the thickness of the negative electrode film, that is, there is a negative electrode film layer at the bottom of the separation area, then after injection, the electrolyte will infiltrate along the negative electrode film layer at the bottom into the non-reaction area, and it will not be able to prevent the lithium ions in the reaction area from flowing into the non-reaction area. Diffusion in the non-reactive zone. Therefore, the depth of the spacer region is equal to the thickness of the negative electrode film layer, that is, the bottom of the spacer region is the current collector of the negative electrode plate.
  • the distance between the side of the spacer region close to the reaction zone and the reaction zone is 1 mm to 10 mm, optionally 2 mm to 4 mm.
  • the side of the separation area close to the reaction area is completely close to the edge of the reaction area, it will affect the safety of the battery core. Lithium precipitation may occur at the edge of the reaction area when the positive and negative electrodes are slightly misaligned. If the side of the separation area close to the reaction area is far away from the reaction area, the negative electrode film layer between the two will still consume lithium, which will worsen the improvement of the first efficiency and cycle performance of the battery cell. Therefore, when the distance between the side of the spacer region close to the reaction zone and the reaction zone is within a given range, the first efficiency and cycle performance of the secondary battery can be further improved.
  • a method for preparing a secondary battery including the following steps:
  • step (2) includes the step of setting a barrier layer on the negative electrode piece
  • the secondary battery includes a positive electrode piece and a negative electrode piece.
  • the positive electrode piece includes a positive electrode current collector and positive electrode film layers on both surfaces of the positive electrode current collector.
  • the negative electrode piece includes a negative electrode current collector and two layers of positive electrode film on both surfaces of the negative electrode current collector.
  • the negative electrode film layer includes a reaction area opposite to the positive electrode film layer and a non-reactive area not opposite to the positive electrode film layer. A barrier layer is provided on the surface of the non-reaction area.
  • the barrier layer is provided by a coating or pasting process.
  • the barrier layer is provided by a pasting process.
  • the barrier layer to prevent electrolyte infiltration is very important and can be provided by two processes: coating or pasting. Since the coating process requires equipment for mixing, coating, baking and other steps, the process is more complicated than the pasting process. Therefore, optionally, the barrier layer is set through the pasting process.
  • the method further includes setting a spacer area along the width direction of the negative electrode piece at an end of the non-reactive area of the negative electrode piece close to the reaction area, and the spacer area is set by water washing, polishing or intermittent coating. .
  • a secondary battery typically includes a positive electrode plate, a negative electrode plate, an electrolyte and a separator.
  • active ions are inserted and detached back and forth between the positive and negative electrodes.
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows ions to pass through.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil can be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the cathode active material may be a cathode active material known in the art for batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials of batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (can also be abbreviated as NCM 811 )), lithium nickel cobalt aluminum oxide
  • lithium-containing phosphates with an olivine structure may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), phosphoric acid At least one of a composite material of lithium manganese and carbon, a composite material of lithium manganese iron phosphate, or a composite material of lithium manganese iron phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • composites of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate
  • phosphoric acid At least one of a composite material of lithium manganese and carbon, a composite material of lithium manganese iron phosphate, or a composite material of lithium manganese iron phosphate and carbon.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the positive electrode film layer optionally further includes a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, where the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative active material may be a negative active material known in the art for batteries.
  • the negative active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon carbon composites, silicon nitrogen composites and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the negative electrode film layer optionally further includes a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polysodium acrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active materials, conductive agents, binders and any other components in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode piece can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the type of electrolyte in this application can be selected according to needs.
  • the electrolyte can be liquid, gel, or completely solid.
  • the electrolyte is an electrolyte solution.
  • the electrolyte solution includes electrolyte salts and solvents.
  • the electrolyte salt may be selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bistrifluoromethanesulfonimide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium difluorodioxalate phosphate and lithium tetrafluoroxalate phosphate.
  • the solvent may be selected from ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, Methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate At least one of ester, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • ethylene carbonate ethylene carbonate
  • propylene carbonate propylene carbonate
  • ethyl methyl carbonate diethyl carbonate
  • dimethyl carbonate diprop
  • the electrolyte optionally further includes additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • 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. When the isolation film is a multi-layer composite film, 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 separator film can be made into an electrode assembly (battery core) through a winding process or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 4 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. 6 is 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 .
  • 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.
  • Figure 9 is 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.
  • the negative electrode film layer is 61 ⁇ m, and is cut into negative electrode pieces with a length of 735 mm and a film width of 93 mm.
  • the coating weight of the negative electrode piece is 9.4 mg/cm 2 and the compacted density is 1.55 g/cm 3 .
  • the negative electrode sheet includes a reaction area that is set opposite to the positive electrode film layer and a non-reactive area that is not set opposite to the positive electrode film layer (i.e., the empty roll non-reaction area and the finishing non-reaction area). Paste a single sheet on the non-reaction area of the negative electrode sheet.
  • a surface-adhesive polyethylene film is used as the barrier layer.
  • the adhesive force of the polyethylene film is 470N/m and the thickness is 20 ⁇ m.
  • ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1 to obtain an organic solvent.
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • LiPF 6 fully dried lithium salt LiPF 6 in the above organic solvent.
  • the concentration of lithium salt is 1mol/L, and the electrolyte is obtained by mixing evenly.
  • a polyethylene film with a thickness of 12 ⁇ m was selected as the isolation film.
  • the secondary battery is generally prepared with reference to Example 1. The difference is that in the preparation of the negative electrode sheet, a single-sided adhesive polyethylene film is pasted on the non-reactive area of the negative electrode sheet as a barrier layer.
  • the adhesive force of the polyethylene film are 450N/m, and the thicknesses are 6 ⁇ m and 40 ⁇ m respectively.
  • the secondary battery is generally prepared with reference to Example 1. The difference is that in the preparation of the negative electrode sheet, the single-sided adhesive polyethylene film is replaced with a single-sided adhesive uniaxially stretched polypropylene film or polyterephthalene. Ethylene glycol formate film and polyvinyl chloride film.
  • the secondary battery was generally prepared as in Example 1, except that in the preparation of the negative electrode sheet, polytetrafluoroethylene was coated as a barrier layer on the non-reactive area of the negative electrode sheet with a thickness of 20 ⁇ m.
  • the secondary battery was generally prepared as in Example 1, except that in the preparation of the negative electrode sheet, polymethyl methacrylate was coated as a barrier layer on the non-reactive area of the negative electrode sheet, with a thickness of 20 ⁇ m.
  • the secondary battery is generally prepared with reference to Embodiment 1. The difference is that in the preparation of the negative electrode piece, a spacer is provided along the width direction of the negative electrode piece at one end of the non-reactive region of the negative electrode piece close to the reaction region.
  • the spacer region It is formed by removing the negative electrode film layer by polishing. Its width is 15mm and its depth is equal to the thickness of the negative electrode film layer, which is 61 ⁇ m.
  • the distance between the side close to the reaction area and the reaction area is 4mm, and the barrier layer starts from the separation area. Set away from the reaction zone.
  • the secondary battery was generally prepared as in Example 9, except that the widths of the separation regions were 5 mm and 50 mm respectively.
  • the secondary battery was generally prepared as in Example 9, except that the depth of the spacer region was 20 ⁇ m, that is, the negative electrode film layer in the spacer region was not completely removed.
  • the secondary battery is generally prepared as in Example 9, except that the distances between the side of the separation area close to the reaction area and the reaction area are 0 mm, 1 mm, 2 mm, 10 mm and 13 mm respectively.
  • the secondary battery is generally prepared as in Example 1, except that in the preparation of the negative electrode sheet, a barrier layer is not provided in the non-reactive region.
  • the capacity measured at 45°C at a rate of 0.02C for 10 hours is marked as C0, then charged at 25°C at a rate of 0.33C to 3.65V, with a constant voltage of 3.65V to 0.05C.
  • the capacity measured is marked as C1
  • the capacity measured at 0.33C discharged to 2.5V is marked as D0, and D0/(C0+C1) ⁇ 100% is the first-week Coulombic efficiency (first effect) of the secondary battery.
  • SOC state of charge
  • Example 1 shows that when a spacer is provided at one end of the non-reactive area of the negative electrode plate close to the reaction area, the first efficiency, storage performance and cycle performance of the secondary battery can be further improved.
  • Example 9 shows that when the depth of the spacer region is equal to the thickness of the negative electrode film layer, the first efficiency, storage performance and cycle performance of the secondary battery can be further improved.
  • Example 9 shows that when the distance between the side of the separation area close to the reaction zone and the reaction zone is 1 mm to 10 mm, the first efficiency, storage performance and cycle performance of the secondary battery can be further improved.
  • the distance between the side of the spacer region close to the reaction zone and the reaction zone is 0mm, the first effect, storage performance and cycle performance of the secondary battery are all good, but if the side of the spacer region close to the reaction zone is completely close to the edge of the reaction zone , the edge of the reaction area may produce lithium precipitation when the positive and negative electrode plates are slightly misaligned, thus affecting the safety of the battery core. Therefore, the distance between the side of the separation area close to the reaction area and the reaction area is greater than 0mm.

Landscapes

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

Abstract

本申请涉及一种二次电池，包括正极极片和负极极片，所述正极极片包括正极集流体和在所述正极集流体两个表面上的正极膜层，所述负极极片包括负极集流体和在所述负极集流体两个表面上的负极膜层，所述负极膜层包括与所述正极膜层相对设置的反应区和不与所述正极膜层相对设置的非反应区，其中，在所述非反应区的表面上设置有阻隔层。本申请还涉及一种制备二次电池的方法、电池模块、电池包和用电装置。

Description

二次电池及其制备方法、电池模块、电池包和用电装置 技术领域
本申请涉及锂电池技术领域，尤其涉及一种二次电池及其制备方法、电池模块、电池包和用电装置。
背景技术
近年来，随着锂离子电池的应用范围越来越广泛，锂离子电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于锂离子电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。
目前业内负极极片涂布工艺大多采用连续涂布的方式，即电芯负极极片的尾部和头部没有留白区(空基材)。虽然没有留白区对极片生产工艺以及产能有很大的优势，但是连续涂布的负极极片有很多没有参与直接脱嵌锂的涂敷层存在，这将消耗一定的锂，导致损失部分容量，恶化电芯首效、循环性能和存储性能。因此，现有的锂离子电池在首效、循环性能和存储性能等方面仍有待改进。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种二次电池，其具有改善的首效、循环性能和存储性能。
为了达到上述目的，本申请提供了一种二次电池及其制备方法、电池模块、电池包和用电装置。
本申请的第一方面提供了一种二次电池，包括正极极片和负极极片，所述正极极片包括正极集流体和在所述正极集流体两个表面上的正极膜层，所述负极极片包括负极集流体和在所述负极集流体两个表面上的负极膜层，所述负极膜层包括与所述正极膜层相对设置的反应 区和不与所述正极膜层相对设置的非反应区，其中，在所述非反应区的表面上设置有阻隔层。
由此，本申请通过在非反应区设置阻隔层，在电芯充放电过程中，由于非反应区被隔离，电解液不能将其浸润，阻断了反应区的锂离子向非反应区扩散的路径，从而提升二次电池的首效、循环性能和存储性能。
在任意实施方式中，所述阻隔层选自不能被电解液浸润的薄膜或涂层；所述薄膜包括聚丙烯、聚乙烯、聚酯纤维和聚氯乙烯中的一种或几种，可选地包括流延聚丙烯、单向拉伸聚丙烯、双向拉伸聚丙烯、聚乙烯、聚酯纤维和聚氯乙烯中的一种或几种，进一步可选地包括聚乙烯；所述涂层包括聚偏氟乙烯、聚四氟乙烯、聚酰胺、聚酰亚胺、聚甲基丙烯酸甲酯、聚氨酯、聚苯乙烯、聚丙烯酸、聚丙烯酰胺、聚丙烯腈以及上述物质的共聚物中的一种或几种。
在任意实施方式中，所述阻隔层的厚度为6μm-40μm，可选地为10μm-20μm。当阻隔层的厚度在所给范围内时，能够保证极片没有大的形变，与电芯完全兼容。
在任意实施方式中，所述薄膜具有粘性，粘结力大于20N/m。当薄膜的粘结力在所给范围内时，能够有效地将薄膜贴敷在非反应区的表面上。
在任意实施方式中，在所述负极极片的所述非反应区靠近所述反应区的一端沿着所述负极极片的宽度方向设置间隔区，并且所述阻隔层自间隔区开始、远离所述反应区设置。当在非反应区靠近反应区的一端设置间隔区时，能够进一步改善二次电池的首效、循环性能和存储性能。
在任意实施方式中，所述间隔区的宽度为5mm-50mm，可选地为10mm-15mm。当间隔区的宽度在所给范围内时，能更好地辅助设置阻隔层，更有效地隔离电解液且不影响极片的加工。
在任意实施方式中，所述间隔区的深度等于所述负极膜层的厚度。当间隔区的深度等于负极膜层的厚度时，会阻止电解液沿着底部的负 极膜层向非反应区浸润，从而阻止反应区的锂离子向非反应区扩散，进而改善二次电池的首效、循环性能和存储性能。
在任意实施方式中，所述间隔区靠近所述反应区的一侧与所述反应区的距离为1mm-10mm，可选地为2mm-4mm。当间隔区靠近反应区的一侧与反应区的距离在所给范围内时，能够进一步改善二次电池的首效和循环性能。
本申请的第二方面还提供一种制备二次电池的方法，包括以下步骤：
(1)制备正极极片；
(2)制备负极极片；
(3)制备隔离膜；
(4)制备电解液；
(5)制备二次电池；
其中，步骤(2)包括在所述负极极片上设置阻隔层的步骤；
所述二次电池包括正极极片和负极极片，所述正极极片包括正极集流体和在所述正极集流体两个表面上的正极膜层，所述负极极片包括负极集流体和在所述负极集流体两个表面上的负极膜层，所述负极膜层包括与所述正极膜层相对设置的反应区和不与所述正极膜层相对设置的非反应区，在所述非反应区的表面上设置有阻隔层。
由此，本申请方法通过简单的工艺在负极极片的非反应区上设置阻隔层，从而隔离非反应区，阻断反应区的锂离子向非反应区扩散，进而提升二次电池的首效、循环性能和存储性能。
在任意实施方式中，所述阻隔层通过涂覆或粘贴工艺设置，可选地，所述阻隔层通过粘贴工艺设置。
本申请的第三方面提供一种电池模块，包括本申请第一方面的二次电池或通过本申请第二方面的方法制备的二次电池。
本申请的第四方面提供一种电池包，包括本申请第三方面的电池模块。
本申请的第五方面提供一种用电装置，包括选自本申请第一方面 的二次电池或通过本申请第二方面的方法制备的二次电池、本申请第三方面的电池模块或本申请第四方面的电池包中的至少一种。
本申请的电池模块、电池包和用电装置包括本申请的二次电池，因而至少具有与所述二次电池相同的优势。
附图说明
图1是本申请一实施方式的二次电池的卷绕型电芯的示意图。
图2是图1所示的本申请一实施方式的二次电池的卷绕型电芯的负极极片的展开示意图。
图3是本申请另一实施方式的二次电池的卷绕型电芯的负极极片的展开示意图。
图4是本申请一实施方式的二次电池的示意图。
图5是图4所示的本申请一实施方式的二次电池的分解图。
图6是本申请一实施方式的电池模块的示意图。
图7是本申请一实施方式的电池包的示意图。
图8是图7所示的本申请一实施方式的电池包的分解图。
图9是本申请一实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的二次电池及其制备方法、电池模块、电池包和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出了最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不 存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
在卷绕或叠片电芯中，由于必须满足负极极片完全覆盖正极极片，所以负极极片必须有一段非反应区不参与与正极极片的直接脱嵌锂。但是在电芯的充电过程中，正极极片的锂离子优先嵌入负极极片的反应区，即与正极极片相对的区域，负极极片反应区的电势逐渐降低，而非反应区一直处于比较高的电势，此时非反应区与负极极片的反应区形成电势差，在电势差的驱动下，反应区的锂离子以缓慢的速度向非反应区扩散嵌入，而嵌入非反应区的锂离子在放电过程中很难再回到正极极片，这就造成了正极极片的不可逆锂损失，最终导致电芯的首效、循环性能和存储性能恶化。
本申请通过在负极极片的非反应区设置阻隔层，在电芯充放电过程中，由于非反应区被隔离，电解液不能将其浸润，阻断了反应区的锂离子向非反应区扩散的路径，从而提升二次电池的首效、循环性能和存储性能。
[二次电池]
本申请的一个实施方式中，本申请提出了一种二次电池，包括正极极片和负极极片，正极极片包括正极集流体和在正极集流体两个表面上的正极膜层，负极极片包括负极集流体和在负极集流体两个表面上的负极膜层，负极膜层包括与正极膜层相对设置的反应区和不与正极膜层相对设置的非反应区，其中，在非反应区的表面上设置有阻隔层。
虽然机理尚不明确，但本申请人意外地发现：本申请通过在负极极片的非反应区上设置阻隔层，在电芯充放电过程中，由于非反应区被隔离，电解液不能将其浸润，阻断了反应区的锂离子向非反应区扩散的路径，降低了正极极片的不可逆锂损失，从而提升二次电池的首效、循环性能和存储性能。
例如，如图1所示，在卷绕型电芯中，正极极片、负极极片和隔离膜采用卷绕工艺制作成电芯。负极极片包括与正极极片相对设置的 反应区和不与正极极片相对设置的非反应区，非反应区包括空卷非反应区和收尾非反应区。
图2为图1所示的卷绕型电芯中的负极极片的展开示意图。如图1和图2所示，负极极片的中部为反应区，一面(A面)的一端为空卷非反应区，另一面(B面)的一端为收尾非反应区，其中在非反应区设置阻隔层。
在一些实施方式中，阻隔层选自不能被电解液浸润的薄膜或涂层；薄膜包括聚丙烯、聚乙烯、聚酯纤维和聚氯乙烯中一种或几种，可选地包括流延聚丙烯、单向拉伸聚丙烯、双向拉伸聚丙烯、聚乙烯、聚酯纤维和聚氯乙烯中的一种或几种，进一步可选地包括聚乙烯；涂层包括聚偏氟乙烯、聚四氟乙烯、聚酰胺、聚酰亚胺、聚甲基丙烯酸甲酯、聚氨酯、聚苯乙烯、聚丙烯酸、聚丙烯酰胺、聚丙烯腈以及上述物质的共聚物中的一种或几种。
由于聚乙烯(PE)薄膜具有无臭、无毒、-90℃至100℃内稳定、耐酸碱、耐有机溶剂、吸水性小、电绝缘性能优良等优点，所以薄膜可选地包括PE薄膜。
在一些实施方式中，聚酯纤维包括聚对苯二甲酸乙二醇酯、聚对苯二甲酸丁二醇酯。
在一些实施方式中，阻隔层的厚度为6μm-40μm，可选地为10μm-20μm。
在本申请的实施例中，需要控制阻隔层的厚度。阻隔层太薄容易破损，太厚将导致极片发生形变。当阻隔层的厚度在所给范围内时，能够保证极片没有大的形变，与电芯完全兼容。
在一些实施方式中，薄膜具有粘性，粘结力大于20N/m，可选地大于200N/m，进一步可选地大于400N/m。
在本申请的实施例中，薄膜具有一定的粘性，粘结力太小无法将薄膜与负极极片上的负极膜层紧密贴合，很容易撕裂，薄膜的粘结力大于20N/m，可选地薄膜粘结力大于负极膜层中颗粒与颗粒间的内聚力，能够有效地将薄膜贴敷在非反应区的表面上。只要能隔绝电解 液，单面粘性或双面粘性的薄膜都可以满足本申请，由于双面粘性的薄膜相对单面粘性的薄膜厚度有所增加，这将导致极片发生更大的形变，所以薄膜可选地为单面粘性的薄膜。
在一些实施方式中，在负极极片的非反应区靠近反应区的一端沿着负极极片的宽度方向设置间隔区，并且阻隔层自间隔区开始、远离反应区设置。
通过在负极极片的非反应区靠近反应区的一端设置间隔区，可以阻止注液后电解液向非反应区浸润，从而阻止反应区的锂离子向非反应区扩散，进而进一步改善二次电池的首效、循环性能和存储性能。
图3是本申请另一实施方式的二次电池的卷绕型电芯的负极极片的展开示意图。如图3所示，负极极片的中部为反应区，一面(A面)的一端为空卷非反应区，另一面(B面)的一端为收尾非反应区，其中非反应区靠近反应区的一端沿着负极极片的宽度方向设置间隔区，并且阻隔层自间隔区开始、远离反应区设置。更具体而言，阻隔层设置在间隔区底部表面、间隔区靠近非反应区的侧面以及远离反应区的非反应区上。
在一些实施方式中，间隔区的宽度为5mm-50mm，可选地为10mm-15mm。
间隔区的宽度太宽影响极片的加工性能，尤其是在冷压阶段导致极片压密不均。宽度太窄将影响后期非反应区贴膜工艺，导致贴膜不紧密，电解液会从底部渗透。当间隔区的宽度在所给范围内时，能更好地辅助设置阻隔层，更有效地隔离电解液且不影响极片的加工。
在一些实施方式中，间隔区的深度等于负极膜层的厚度。
如果间隔区的深度小于负极膜层的厚度，即间隔区的底部有负极膜层，那么注液后电解液会沿着底部的负极膜层向非反应区浸润，无法阻止反应区的锂离子向非反应区扩散。因此，间隔区的深度等于负极膜层的厚度，即间隔区的底部为负极极片的集流体。
在一些实施方式中，间隔区靠近反应区的一侧与反应区的距离为1mm-10mm，可选地为2mm-4mm。
如果间隔区靠近反应区的一侧完全贴近反应区的边缘，将影响电芯安全，反应区的边缘有可能在正负极极片轻微错位的情况下发生析锂。如果间隔区靠近反应区的一侧离反应区较远，两者之间的负极膜层还是会消耗锂，将恶化对电芯首效及循环性能的改善效果。因此，当间隔区靠近反应区的一侧与反应区的距离在所给范围内时，能够进一步改善二次电池的首效和循环性能。
本申请的一个实施方式中，提供一种制备二次电池的方法，包括以下步骤：
(1)制备正极极片；
(2)制备负极极片；
(3)制备隔离膜；
(4)制备电解液；
(5)制备二次电池；
其中，步骤(2)包括在负极极片上设置阻隔层的步骤；
二次电池包括正极极片和负极极片，正极极片包括正极集流体和在正极集流体两个表面上的正极膜层，负极极片包括负极集流体和在负极集流体两个表面上的负极膜层，负极膜层包括与正极膜层相对设置的反应区和不与正极膜层相对设置的非反应区，在非反应区的表面上设置有阻隔层。
在一些实施方式中，阻隔层通过涂覆或粘贴工艺设置，可选地，阻隔层通过粘贴工艺设置。
防止电解液浸润的阻隔层非常重要，可以采用涂敷或粘贴两种工艺设置。由于涂敷工艺需要设备搅拌、涂敷、烘烤等环节，流程相对粘贴工艺较为复杂，因此可选地，阻隔层通过粘贴工艺设置。
在一些实施方式中，所述方法还包括在负极极片的非反应区靠近反应区的一端沿着负极极片的宽度方向设置间隔区，间隔区通过水洗、抛光打磨或者间歇涂布的方式设置。
另外，以下适当参照附图对本申请的二次电池、电池模块、电池 包和用电装置进行说明。
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料可采用本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、 LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811))、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银 及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电 解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸乙烯酯(碳酸亚乙酯)、碳酸丙烯酯(碳酸亚丙酯)、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
[隔离膜]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件(电芯)。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。 软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图4是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图5，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图6是作为一个示例的电池模块4。参照图6，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图7和图8是作为一个示例的电池包1。参照图7和图8，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图9是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
实施例1
(1)正极极片的制备
将正极活性材料磷酸铁锂、导电剂乙炔黑、粘结剂聚偏氟乙烯(PVDF)按质量比96:2:2进行混合，加入溶剂N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌至体系呈均一状，获得正极浆料；将正极浆料均匀涂覆在厚度为12μm的正极集流体铝箔的两个表面上，在115℃干燥15min，冷压得到单侧厚度为84μm的正极膜层，分切得到长605mm、膜宽为88mm的正极极片，涂布重量为20mg/cm 2，压实密度为2.4g/cm 3。
(2)负极极片的制备
将负极活性材料人造石墨、导电剂乙炔黑、增稠剂羧甲基纤维素钠(CMC)、粘结剂SBR按质量比96.4:1:1.2:1.4进行混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得负极浆料；将负极浆料均匀涂覆在厚度为8μm的负极集流体铜箔的两个表面上，在115℃干燥15min，冷压得到单侧厚度为61μm的负极膜层，分切得到长735mm、膜宽为93mm的负极极片，负极极片的涂布重量为9.4mg/cm 2，压实密度为1.55g/cm 3。负极极片包括将与正极膜层相对设置的反应区和不与正极膜层相对设置的非反应区(即空卷非反应区和收尾非反应区)，在负极极片的非反应区粘贴单面粘性的聚乙烯薄膜作为阻隔层，聚乙烯薄膜的粘结力为470N/m，厚度为20μm。
(3)电解液的制备
将碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比1:1:1进行混合得到有机溶剂，将充分干燥的锂盐LiPF 6溶解于上述有机溶剂中，锂盐的浓度为1mol/L，混合均匀得到电解液。
(4)隔离膜的制备
选用厚度为12μm的聚乙烯膜作为隔离膜。
(5)二次电池的制备
将上述正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极极片之间起到隔离的作用，然后卷绕得到裸电芯；将裸电芯置于外包装壳中，干燥后按4.2g/Ah的注液系数注入电解液，经过真空封装、静置、化成、整形等工序，获得容量为3Ah左右的二次电池。
实施例2-3
二次电池的制备整体上参照实施例1，区别在于，在负极极片的制备中，在负极极片的非反应区粘贴单面粘性的聚乙烯薄膜作为阻隔层，聚乙烯薄膜的粘结力为450N/m，厚度分别为6μm和40μm。
实施例4-6
二次电池的制备整体上参照实施例1，区别在于，在负极极片的制备中，将单面粘性的聚乙烯薄膜分别替换为单面粘性的单向拉伸聚丙烯薄膜、聚对苯二甲酸乙二醇酯薄膜和聚氯乙烯薄膜。
实施例7
二次电池的制备整体上参照实施例1，区别在于，在负极极片的制备中，在负极极片的非反应区涂覆聚四氟乙烯作为阻隔层，其厚度为20μm。
实施例8
二次电池的制备整体上参照实施例1，区别在于，在负极极片的制备中，在负极极片的非反应区涂覆聚甲基丙烯酸甲酯作为阻隔层，其厚度为20μm。
实施例9
二次电池的制备整体上参照实施例1，区别在于，在负极极片的制备中，在负极极片的非反应区靠近反应区的一端沿着负极极片的宽度方向设置间隔区，间隔区通过抛光打磨的方式去除负极膜层而形成，其宽度为15mm，深度等于负极膜层的厚度，即61μm，靠近反应区的一侧与反应区的距离为4mm，并且阻隔层自间隔区开始、远离所述反应区设置。
实施例10-11
二次电池的制备整体上参照实施例9，区别在于，间隔区的宽度分别为5mm和50mm。
实施例12
二次电池的制备整体上参照实施例9，区别在于，间隔区的深度为20μm，即未完全去除间隔区的负极膜层。
实施例13-17
二次电池的制备整体上参照实施例9，区别在于，间隔区靠近反应区的一侧与反应区的距离分别为0mm、1mm、2mm、10mm和13mm。
对比例1
二次电池的制备整体上参照实施例1，区别在于，在负极极片的制备中，不在非反应区设置阻隔层。
二次电池性能测试
1.二次电池的首效
在45℃下以0.02C倍率充电10h所测得的容量标记为C0，然后在25℃下以0.33C倍率充电至3.65V，3.65V恒压至0.05C所测得的容量标记为C1，最后0.33C放电至2.5V所测得的容量标记为D0，D0/(C0+C1)×100％为二次电池的首周库伦效率(首效)。
2.二次电池的存储性能
在45℃下，将二次电池在100％SOC(荷电状态)下存储，前60天每15天采集一次数据，60天后每30天采集一次数据直至容量衰减至80％，记录存储天数。
3.二次电池的循环性能
在45℃下，将二次电池以1C倍率充电至3.65V、3.65V恒压至0.05C、以1C倍率放电至2.5V，重复以上步骤进行满充满放循环测试，直至二次电池的容量衰减至初始容量的80％，记录循环圈数。
按照上述过程分别测试上述实施例和对比例中得到的二次电池，具体数值参见表1。
Figure PCTCN2022092739-appb-000001
Figure PCTCN2022092739-appb-000002
由表1可知，上述所有实施例的二次电池的首效、容量为80％时存储天数和容量保持率80％时循环圈数均高于对比例的二次电池。
综合比较实施例1至实施例8，相比于对比例1，通过在负极极片的非反应区设置阻隔层，可以明显改善二次电池的首效、存储性能和循环性能。
综合比较实施例1和实施例9至实施例17，当在负极极片的非反应区靠近反应区的一端设置间隔区时，能够进一步改善二次电池的首效、存储性能和循环性能。
综合比较实施例9和实施例12，当间隔区的深度等于负极膜层的厚度时，能够进一步改善二次电池的首效、存储性能和循环性能。
综合比较实施例9和实施例13至实施例17，当间隔区靠近反应区的一侧与反应区的距离为1mm-10mm，能够进一步改善二次电池的首效、存储性能和循环性能。尽管当间隔区靠近反应区的一侧与反应区的距离为0mm时，二次电池的首效、存储性能和循环性能均良好，但是如果间隔区靠近反应区的一侧完全贴近反应区的边缘，反应区的边缘有可能在正负极极片轻微错位的情况下发生析锂，从而影响电芯安全，因此间隔区靠近反应区的一侧与反应区的距离大于0mm。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (13)

  1. 一种二次电池，包括正极极片和负极极片，所述正极极片包括正极集流体和在所述正极集流体两个表面上的正极膜层，所述负极极片包括负极集流体和在所述负极集流体两个表面上的负极膜层，所述负极膜层包括与所述正极膜层相对设置的反应区和不与所述正极膜层相对设置的非反应区，其中，在所述非反应区的表面上设置有阻隔层。
  2. 根据权利要求1所述的二次电池，其中，所述阻隔层选自不能被电解液浸润的薄膜或涂层；所述薄膜包括聚丙烯、聚乙烯、聚酯纤维和聚氯乙烯中的一种或几种，可选地包括流延聚丙烯、单向拉伸聚丙烯、双向拉伸聚丙烯、聚乙烯、聚酯纤维和聚氯乙烯中的一种或几种，进一步可选地包括聚乙烯；所述涂层包括聚偏氟乙烯、聚四氟乙烯、聚酰胺、聚酰亚胺、聚甲基丙烯酸甲酯、聚氨酯、聚苯乙烯、聚丙烯酸、聚丙烯酰胺、聚丙烯腈以及上述物质的共聚物中的一种或几种。
  3. 根据权利要求1或2所述的二次电池，其中，所述阻隔层的厚度为6μm-40μm，可选地为10μm-20μm。
  4. 根据权利要求2至3中任一项所述的二次电池，其中，所述薄膜具有粘性，粘结力大于20N/m。
  5. 根据权利要求1至4中任一项所述的二次电池，其中，在所述负极极片的所述非反应区靠近所述反应区的一端沿着所述负极极片的宽度方向设置间隔区，并且所述阻隔层自间隔区开始、远离所述反应区设置。
  6. 根据权利要求5所述的二次电池，其中，所述间隔区的宽度为5mm-50mm，可选地为10mm-15mm。
  7. 根据权利要求5或6所述的二次电池，其中，所述间隔区的深度等于所述负极膜层的厚度。
  8. 根据权利要求5至7中任一项所述的二次电池，其中，所述间隔区靠近所述反应区的一侧与所述反应区的距离为1mm-10mm，可选地为2mm-4mm。
  9. 一种制备二次电池的方法，包括以下步骤：
    (1)制备正极极片；
    (2)制备负极极片；
    (3)制备隔离膜；
    (4)制备电解液；
    (5)制备二次电池；
    其中，步骤(2)包括在所述负极极片上设置阻隔层的步骤；
    所述二次电池包括正极极片和负极极片，所述正极极片包括正极集流体和在所述正极集流体两个表面上的正极膜层，所述负极极片包括负极集流体和在所述负极集流体两个表面上的负极膜层，所述负极膜层包括与所述正极膜层相对设置的反应区和不与所述正极膜层相对设置的非反应区，在所述非反应区的表面上设置有阻隔层。
  10. 根据权利要求9所述的方法，其中，所述阻隔层通过涂覆或粘贴工艺设置，可选地，所述阻隔层通过粘贴工艺设置。
  11. 一种电池模块，其中，包括权利要求1至8中任一项所述的二次电池或通过权利要求9或10所述的方法制备的二次电池。
  12. 一种电池包，其中，包括权利要求11所述的电池模块。
  13. 一种用电装置，其中，包括选自权利要求1至8中任一项所述的二次电池或通过权利要求9或10所述的方法制备的二次电池、权利要求11所述的电池模块或权利要求12所述的电池包中的至少一种。
PCT/CN2022/092739 2022-05-13 2022-05-13 二次电池及其制备方法、电池模块、电池包和用电装置 WO2023216241A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
PCT/CN2022/092739 WO2023216241A1 (zh) 2022-05-13 2022-05-13 二次电池及其制备方法、电池模块、电池包和用电装置
KR1020247004128A KR20240027836A (ko) 2022-05-13 2022-05-13 이차전지 및 이의 제조 방법, 배터리모듈, 배터리팩 및 전기기기
CN202280050304.1A CN117652051A (zh) 2022-05-13 2022-05-13 二次电池及其制备方法、电池模块、电池包和用电装置
EP22938760.0A EP4318726A1 (en) 2022-05-13 2022-05-13 Secondary battery and preparation method therefor, and battery module, battery pack and electric apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/092739 WO2023216241A1 (zh) 2022-05-13 2022-05-13 二次电池及其制备方法、电池模块、电池包和用电装置

Publications (1)

Publication Number Publication Date
WO2023216241A1 true WO2023216241A1 (zh) 2023-11-16

Family

ID=88729523

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/092739 WO2023216241A1 (zh) 2022-05-13 2022-05-13 二次电池及其制备方法、电池模块、电池包和用电装置

Country Status (4)

Country Link
EP (1) EP4318726A1 (zh)
KR (1) KR20240027836A (zh)
CN (1) CN117652051A (zh)
WO (1) WO2023216241A1 (zh)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004146222A (ja) * 2002-10-25 2004-05-20 Sanyo Electric Co Ltd 非水二次電池
JP2011081973A (ja) * 2009-10-05 2011-04-21 Toyota Motor Corp リチウムイオン二次電池、車両及び電池搭載機器
CN215418292U (zh) * 2020-11-04 2022-01-04 惠州锂威新能源科技有限公司 一种安全锂离子电池卷芯及锂离子电池
CN216436083U (zh) * 2021-12-13 2022-05-03 珠海冠宇电池股份有限公司 卷芯及电池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004146222A (ja) * 2002-10-25 2004-05-20 Sanyo Electric Co Ltd 非水二次電池
JP2011081973A (ja) * 2009-10-05 2011-04-21 Toyota Motor Corp リチウムイオン二次電池、車両及び電池搭載機器
CN215418292U (zh) * 2020-11-04 2022-01-04 惠州锂威新能源科技有限公司 一种安全锂离子电池卷芯及锂离子电池
CN216436083U (zh) * 2021-12-13 2022-05-03 珠海冠宇电池股份有限公司 卷芯及电池

Also Published As

Publication number Publication date
CN117652051A (zh) 2024-03-05
KR20240027836A (ko) 2024-03-04
EP4318726A1 (en) 2024-02-07

Similar Documents

Publication Publication Date Title
EP4024533A1 (en) Secondary battery, apparatus comprising secondary battery, preparation method for secondary battery, and adhesive composition
WO2022041259A1 (zh) 二次电池及其制备方法与包含二次电池的电池模块、电池包及装置
WO2023029002A1 (zh) 负极集流体、含有其的二次电池、电池模块、电池包及用电装置
WO2024012166A1 (zh) 二次电池及用电装置
US20230291043A1 (en) Negative electrode sheet and method for preparing the same, secondary battery, battery module, battery pack, and electrical apparatus
WO2023082924A1 (zh) 极片、锂离子电池、电池模块、电池包及用电装置
WO2023087218A1 (zh) 负极极片及其制备方法、二次电池、电池模块、电池包和用电装置
WO2023142024A1 (zh) 一种长寿命二次电池及电池模块、电池包和用电装置
WO2023137624A1 (zh) 二次电池、电池模块、电池包以及用电装置
WO2023060529A1 (zh) 锂离子电池
WO2023050406A1 (zh) 锂离子电池及包含其的电池模块、电池包和用电装置
WO2023004633A1 (zh) 一种电池、电池模块、电池包和用电装置
WO2023216241A1 (zh) 二次电池及其制备方法、电池模块、电池包和用电装置
WO2023216240A1 (zh) 二次电池及其制备方法、电池模块、电池包和用电装置
CN116547838A (zh) 正极极片、二次电池及其制备方法与包含该二次电池的电池模块、电池包和用电装置
WO2023141954A1 (zh) 锂离子电池、电池模块、电池包和用电装置
WO2024007318A1 (zh) 电解液及包含其的锂离子电池
WO2023240600A1 (zh) 粘结剂组合物及包括其的负极极片
WO2024040471A1 (zh) 正极极片及其制备方法、二次电池和用电装置
WO2023216130A1 (zh) 一种电解液、二次电池、电池模块、电池包和用电装置
WO2023193230A1 (zh) 电解液、二次电池、电池模块、电池包和用电装置
WO2023174012A1 (zh) 正极极片、锂离子二次电池、电池模块、电池包和用电装置
WO2023240595A1 (zh) 负极极片及其制造方法、电极组件、及二次电池
WO2024040585A1 (zh) 补锂浆料、正极浆料、二次电池、二次电池的制备方法和用电装置
WO2023082036A1 (zh) 集流体及其制备方法、二次电池、电池模块、电池包和用电装置

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2022938760

Country of ref document: EP

Effective date: 20231103

WWE Wipo information: entry into national phase

Ref document number: 202280050304.1

Country of ref document: CN

ENP Entry into the national phase

Ref document number: 20247004128

Country of ref document: KR

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 1020247004128

Country of ref document: KR