Electrode assembly and secondary battery

Abstract

The embodiment of the application relates to the field of new energy, and provides an electrode assembly and a secondary battery. The electrode assembly of the embodiment of the application comprises a pole piece and a separation film which are arranged in a stack, the edge of the pole piece is bonded with a spacing adhesive tape, the spacing adhesive tape is located between the pole piece and the separation film, and a part of the spacing adhesive tape is bonded with the pole piece; the spacing adhesive tape comprises a glue-free area and a glue-coated area for bonding, the glue-coated area is located on the surface of the pole piece and is bonded with the pole piece, and the glue-free area extends outward relative to the pole piece. The electrode assembly of the application is at least not prone to the phenomenon that burrs pierce the separation film, the pole piece can be fully soaked, and the safety performance, output power and service life of the secondary battery are improved.

Description

Technical Field

[0001] This application relates to the field of new energy, and in particular to an electrode assembly and a secondary battery. Background Technology

[0002] Lithium-ion batteries and similar rechargeable batteries are widely used as energy storage devices in portable electronic products, electric vehicles, aerospace, and energy storage. During the manufacturing of rechargeable batteries, the electrodes need to be cut, which easily creates burrs on the edges. These burrs can puncture the separator, causing a short circuit between the positive and negative electrodes, which compromises the safety performance of the rechargeable battery. Furthermore, burrs can detach due to mechanical stress during battery assembly or use, forming free metal particles that further increase the risk of short circuits. Stacked batteries, for example, are formed by alternately stacking positive and negative electrodes and a separator. They offer advantages such as high energy density, uniform current distribution, structural stability, flexible shape design, and good safety, making them particularly suitable for high-rate charging and discharging and irregularly shaped batteries. However, stacked batteries have a large number of electrodes, and the burrs on the edges of the electrodes are more likely to puncture the separator.

[0003] Therefore, in the manufacturing process of secondary batteries (such as in the stacking process), high-precision cutting, ceramic edge coating, or laser cleaning are required to strictly control burrs, but these operations are quite cumbersome. Although there are currently methods that use adhesive layers to bond to the edges of the electrodes to fix the burrs, this makes it difficult for the electrode edges to be fully wetted by the electrolyte, which is detrimental to the output power and service life of the secondary battery. Summary of the Invention

[0004] This application provides an electrode assembly and a secondary battery, which at least helps to reduce the occurrence of burrs piercing the separator and also allows the electrode to be fully wetted, thereby improving the safety performance, output power and service life of the secondary battery.

[0005] According to some embodiments of this application, one aspect of this application provides an electrode assembly, including: an electrode sheet and a separator film stacked together, with a spacer tape adhered to the edge of the electrode sheet, the spacer tape being located between the electrode sheet and the separator film, and a portion of the spacer tape being adhered to the electrode sheet; the spacer tape includes a non-adhesive area and an adhesive-coated area for adhesion, the adhesive-coated area being located on the surface of the electrode sheet and adhered to the electrode sheet, and the non-adhesive area extending outward relative to the electrode sheet.

[0006] In some embodiments of this application, the width of the adhesive coating area is 0.5mm to 5mm.

[0007] In some embodiments of this application, the width of the adhesive-free area is 0.5mm to 5mm.

[0008] In some embodiments of this application, the spacer tape includes a base film layer, and a portion of the base film layer near the surface of the electrode is provided with an adhesive layer; the portion of the spacer tape with the adhesive layer is the coated area, and the portion of the spacer tape without the adhesive layer is the uncoated area.

[0009] In some embodiments of this application, the thickness of the spacer tape is 10μm to 50μm.

[0010] In some embodiments of this application, the electrode includes a current collector, and at least one surface of the current collector is provided with an active layer.

[0011] In some embodiments of this application, the thickness of the electrode is 50 μm to 300 μm.

[0012] In some embodiments of this application, the electrode includes a positive electrode and a negative electrode, and the positive electrode and the negative electrode are arranged alternately in sequence; the number of positive electrodes is not less than two.

[0013] In some embodiments of this application, the thickness of the separator is 1 μm to 50 μm.

[0014] According to some embodiments of this application, another aspect of this application also provides a secondary battery, including an electrolyte and the above-described electrode assembly, wherein the electrode assembly is immersed in the electrolyte.

[0015] The technical solution provided in this application has at least the following advantages: This application provides an electrode assembly and a secondary battery. In the electrode assembly of this application, the adhesive area of ​​the spacer tape can fix the burrs on the edge of the electrode, reducing the occurrence of burrs piercing the separator and improving the safety performance of the secondary battery. In addition, when the electrode assembly is in use, due to the surface tension of the liquid, after the electrolyte is wetted in the non-adhesive area of ​​the spacer tape, it will also wet the edge of the electrode along the non-adhesive area. In this way, the entire edge of the electrode can be fully wetted, which is beneficial to improving the output power and service life of the secondary battery. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1This is a schematic diagram of the structure of an electrode assembly provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a spacer tape provided in an embodiment of this application; Figure 3 This is a schematic diagram of the layer structure of a spacer tape provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of an electrode sheet during the fabrication process according to an embodiment of this application; Figure 5 This is a schematic diagram of the spacer tape used in the preparation of an electrode sheet according to an embodiment of this application.

[0018] Marking explanation: 001-Electrode assembly; 100-Electrode sheet; 110-Electrode tab; 200-Spacer tape; 210-Glue-coated area; 220-No-glue area; 230-Base film layer; 240-Adhesive layer. Detailed Implementation

[0019] As the background technology shows, burrs are easily generated at the edges of electrodes during the fabrication of secondary batteries, reducing the safety performance of the batteries. While there are methods to add an adhesive layer to the electrode edges to prevent burrs from piercing the separator, this method also means that the edges of the electrodes are not easily and thoroughly wetted by the electrolyte, or the wetting time is too long. This can easily reduce the output power and lifespan of the electrode assembly and the secondary battery. Furthermore, during the fabrication of the electrode assembly, a cutter is used to cut the adhesive layer, and the cutter surface easily adheres to the adhesive layer, reducing work efficiency and contaminating the electrode assembly.

[0020] This application provides an electrode assembly 001 and a secondary battery. The electrode assembly 001 of this application provides a spacer tape 200, which can reduce the occurrence of burrs piercing the separator, thereby improving the safety performance of the secondary battery. On the other hand, it can also ensure that the edges of the electrode 100 are fully wetted by the electrolyte, which is beneficial to improving the output power and service life of the electrode assembly 001 and the secondary battery.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0024] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of other elements or features. Therefore, the term "below" may cover both above and below orientation depending on the context in which the term is used, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0025] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0026] In the description of embodiments of this application, the terms "about," "approximately," "roughly," or "about" for referring to a specific parameter include numerical values, and those skilled in the art will understand that the deviation from the numerical value is within the acceptable tolerance of the specific parameter. For example, "about" or "about" for a numerical value may include additional numerical values ​​that are in the range of 90.0% to 110.0% of the numerical value, such as in the range of 95.0% to 105.0%, 97.5% to 102.5%, 99.0% to 101.0%, 99.5% to 100.5%, or 99.9% to 100.1%.

[0027] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. Furthermore, when describing a component as "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0028] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. The formation or provision of a second component above or on a first component, or on the surface of a first component, or on one side of a first component, may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be present between the first and second components, thereby preventing direct contact between the first and second components. For simplicity and clarity, various components may be drawn at different scales. In the drawings, some layers / components may be omitted for simplicity. Unless otherwise specified, the formation or provision of a second component on the surface of a first component refers to direct contact between the first and second components. The term "component" may refer to a layer, film, region, portion, structure, etc.

[0029] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0030] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0031] like Figures 1-5 As shown, this application provides an electrode assembly 001. The electrode assembly 001 includes stacked electrode sheets 100 and a separator (not shown in the figure). A spacer tape 200 is adhered to the edge of the electrode sheet 100, located between the electrode sheet 100 and the separator, and a portion of the spacer tape 200 is bonded to the electrode sheet 100. The spacer tape 200 includes an adhesive-coated area 210 and an adhesive-free area 220 for bonding. The adhesive-coated area 210 is located on the surface of the electrode sheet 100 and bonded to it, while the adhesive-free area 220 extends outward relative to the electrode sheet 100. Figure 1 and Figure 2 As shown.

[0032] The adhesive-coated area 210 of the spacer tape 200 serves an adhesive function. Since the adhesive-coated area 210 of the spacer tape 200 adheres to the edge of the electrode 100, burrs on the edge of the electrode 100 are fixed by the adhesive-coated area 210 of the spacer tape 200, greatly reducing the phenomenon of burrs piercing the separator. Therefore, when the electrode assembly 001 of this application is used in a secondary battery, it can improve the safety performance of the secondary battery. The adhesive-free area 220 of the spacer tape 200 does not have an adhesive function. Moreover, since the adhesive-free area 220 extends outward relative to the electrode 100, when the electrode assembly 001 is immersed in the electrolyte, the electrolyte will first wet the adhesive-free area 220. Then, due to the surface tension of the liquid, the electrolyte will wet the edge of the electrode 100 along the adhesive-free area 220. The entire edge of the electrode 100 can be fully wetted, which is beneficial to improving the output power and service life of the secondary battery. In addition, when preparing the electrode assembly 001, the spacer tape 200 is attached to the surface of the electrode 100 through the adhesive coating area 210. The cutter will cut the electrode 100 from the non-adhesive area 220 of the spacer tape 200. In this way, the cutter will not come into contact with the adhesive coating area 210 of the spacer tape 200, and the adhesive coating area 210 will not stick to the cutter. This can improve production efficiency and prevent the electrode assembly 001 from being contaminated.

[0033] Furthermore, it should be noted that the spacer tape 200 can be applied not only to the cut edges of the electrode 100, but also to the uncut edges. From Figure 1 As can be seen from above, the spacer tape 200 can be applied not only along the first direction but also along the second direction, with the first and second directions being perpendicular to each other.

[0034] In some embodiments of this application, in order to ensure that the adhesive coating area 210 can both improve the safety performance of the electrode assembly 001 and the secondary battery, and also avoid having a significant adverse impact on the energy density of the electrode assembly 001 and the secondary battery, the width of the adhesive coating area 210 is typically controlled to be 0.5mm to 5mm. In some embodiments of this application, in order to ensure the effect of fixing burrs and effectively isolating the electrode sheet and the separator, the width of the adhesive-free area 220 is typically set to be 0.5mm to 5mm.

[0035] It should be noted that, in this embodiment of the application, since the spacer tape 200 is arranged along the edge of the electrode 100 and is elongated in shape, the “width of the adhesive area 210” refers to the length of the relatively shorter side of the adhesive area 210; similarly, the “width of the non-adhesive area 220” refers to the length of the relatively shorter side of the non-adhesive area 220.

[0036] To ensure the adhesive application area 210 of the spacer tape 200 has an adhesive effect, in some embodiments of this application, the spacer tape 200 includes a base film layer 230. A portion of the base film layer 230 near the surface of the electrode 100 is provided with an adhesive layer 240. The portion with the adhesive layer 240 is the adhesive application area 210, while the portion without the adhesive layer 240 is the non-adhesive area 220. A schematic diagram of its layer structure is shown below. Figure 3 As shown. Due to the presence of the adhesive layer 240, the surface of the coated area 210 near the electrode 100 has an adhesive effect; while since the adhesive-free area 220 does not have the adhesive layer 240, the adhesive-free area 220 does not have an adhesive effect. This application does not have any particular restrictions on the materials of the base film layer 230 and the adhesive layer 240, as long as they can meet the purpose of this application. In some embodiments of this application, the material of the base film layer 230 includes PET (Polyethylene terephthalate), PI (Polyimide), PC (Polycarbonate), etc., and the material of the adhesive layer 240 includes acrylic adhesive, acrylic adhesive, silicone adhesive, or rubber-based adhesive, etc.

[0037] Of course, in some embodiments of this application, the spacer tape 200 may also adopt other structures. For example, the spacer tape 200 may have only one layer, but the types of adhesive-coated areas 210 and non-adhesive areas 220 may be different. The material of the adhesive-coated area 210 may be adhesive, while the material of the non-adhesive area 220 may not be adhesive. This application will not elaborate further here. The adhesive-coated area 210 is usually made adhesive by coating with an adhesive material, which may be full-coverage coating, spaced coating, dotted coating, or other various coating methods. This application does not have any particular limitations on this.

[0038] In some embodiments of this application, in order to reduce the thickness of the electrode assembly 001 without affecting the adhesive performance of the spacer tape 200, the thickness of the spacer tape 200 is usually set to 10μm~50μm; reducing the thickness of the electrode assembly 001 is beneficial to improving the space utilization of the secondary battery.

[0039] It should be noted that in the embodiments of this application, the "thickness of the spacer tape 200" is based on the thickness of the thickest area. If the adhesive-coated area 210 of the spacer tape 200 has the greatest thickness, then the thickness of the spacer tape 200 refers to the thickness of the adhesive-coated area 210; if the non-adhesive area 220 of the spacer tape 200 has the greatest thickness, then the thickness of the spacer tape 200 refers to the thickness of the non-adhesive area 220. In some embodiments of this application, in order to allow the electrolyte to more fully penetrate the edge of the electrode 100, the thickness of the non-adhesive layer is usually set to be smaller than the thickness of the adhesive layer.

[0040] The embodiments of this application do not have special requirements for the electrode 100 and the separator, as long as they can meet the purpose of this application. As an example, the embodiments of this application will specifically describe the electrode 100 and the separator.

[0041] 100g of polar film The electrode 100 includes a current collector, and at least one surface of the current collector is provided with an active layer. In this application, the active layer can be disposed on one surface or on two surfaces in the thickness direction of the current collector. Furthermore, in this application, the "surface of the current collector" can be the entire area of ​​the current collector or only a portion thereof; there is no particular limitation as long as the purpose of this application is achieved. Moreover, there is no particular limitation on the thickness of the electrode 100, as long as the purpose of this application is met. As an example, in some embodiments of this application, the thickness of the electrode 100 is 50 μm to 300 μm. The edge of the electrode 100 also extends outward to form a tab for leading out current, such as... Figure 1 and Figure 4 As shown.

[0042] The electrode 100 is divided into a positive electrode and a negative electrode, and in the electrode assembly 001, the positive electrode and the negative electrode are arranged alternately in sequence. Since the spacer tape 200 of this application is particularly suitable for stacked cells, in some embodiments of this application, the number of positive electrode (or negative electrode) is not less than two.

[0043] The current collector in the positive electrode is called the positive current collector, and the active layer is the positive active layer. The main components of the positive active layer include the positive active material, which can be any material capable of reversibly inserting and de-intercalating Li. + Na +Substances containing alkali metal ions are used to ensure the normal charging and discharging of the electrochemical device. For example, positive electrode active materials include, but are not limited to, at least one of lithium iron phosphate (LiFePO4), lithium cobalt oxide (LiCoO2), lithium manganese oxide, lithium nickel oxide, and ternary materials. Ternary materials include, but are not limited to, LiNi x Co y Mn z O2, LiNi x Co y Al z At least one of O2, etc., and the contents of Ni, Co, Mn, Al, etc., can be adjusted to ensure x+y+z=1. For example, the ternary material can be LiNi. 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.88 Co 0.08 Mn 0.04 O2, LiNi 0.8 Co 0.15 Mn 0.05 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.88 Co 0.1 Mn 0.02 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.88 Co 0.1 Al 0.02 O2, etc. The materials for the positive electrode current collector include, but are not limited to, metals such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and materials such as carbon cloth and carbon paper. In preparing the positive electrode sheet, the components in the positive electrode active layer can be dissolved or dispersed in a liquid solvent to form a positive electrode slurry. This slurry is then coated onto the positive electrode current collector and dried, thereby forming the positive electrode active layer on the current collector, thus obtaining the positive electrode sheet. When preparing the positive electrode using this method, there are no particular restrictions on the solvent in the positive electrode slurry, as long as it can dissolve or disperse the aforementioned components. Specifically, the solvent in the positive electrode slurry includes, but is not limited to, N-methylpyrrolidone (NMP) and ethylene carbonate (EC). Alternatively, in preparing the positive electrode sheet, the various components in the positive electrode active layer can be dry-mixed to form a sheet, which is then pressed onto the positive electrode current collector.

[0044] The current collector of the negative electrode sheet is the negative electrode current collector, and the active layer is the negative electrode active layer. The negative electrode active layer mainly contains negative electrode active materials, and this application does not have any particular limitations on the negative electrode active materials. Specifically, the negative electrode active materials may include at least one of carbon materials or silicon-based materials. More specifically, carbon materials include, but are not limited to, at least one of natural graphite, artificial graphite, mesophase micro carbon spheres, hard carbon, or soft carbon; silicon-based materials include, but are not limited to, at least one of silicon, silicon-oxygen composite materials, or silicon-carbon composite materials. The material of the negative electrode current collector includes, but is not limited to, copper foil, aluminum foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a polymer substrate coated with a conductive metal, etc., and this application does not have any particular limitations. Among them, the conductive metal includes, but is not limited to, copper, nickel, or titanium, and the polymer substrate material includes, but is not limited to, at least one of polyethylene, polypropylene, ethylene-propylene copolymer, polyethylene terephthalate, polyethylene terephthalate, or poly(p-phenylene terephthalate). Similar to the preparation of the positive electrode, the preparation of the negative electrode can be achieved either by preparing a negative electrode slurry, coating it onto a negative electrode current collector, and drying it to form a negative electrode active layer, thus obtaining the negative electrode sheet; or by dry mixing the components of the negative electrode active layer to form a sheet, which is then pressed onto the negative electrode current collector to form the negative electrode active layer, thereby obtaining the negative electrode sheet. The solvent in the negative electrode slurry can be any of aqueous or organic solvents. Aqueous solvents include, but are not limited to, mixtures of alcohol and water or water itself. Organic solvents include, but are not limited to, aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N,N-dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide, and tetrahydrofuran (THF); amides such as N-methylpyrrolidone (NMP), dimethylformamide, and dimethylacetamide; and aprotic polar solvents such as hexamethylphosphoramide and dimethyl sulfoxide.

[0045] Separating membrane The separator, stacked with the electrode, serves to isolate the positive and negative electrode sheets, preventing direct contact and short circuits. This application does not impose special requirements on the material and thickness of the separator, as long as it meets the purpose of this application. As an example, in some embodiments of this application, the thickness of the separator can be 1μm to 50μm; specifically, the thickness can be 1μm, 10μm, 25μm, 40μm, 50μm, etc., or within a range of any two of the above values. It should be noted that the separator of this application can cover only the entire adhesive-coated area 210 of the spacer tape 200, or it can cover the entire adhesive-coated area 210 and the entire unadhesive area 220 of the spacer tape 200, or it can cover the entire adhesive-coated area 210 and part of the unadhesive area 220 of the spacer tape 200. This application has no particular limitations on this, as long as the separator can effectively isolate the positive and negative electrode sheets.

[0046] This application also provides a secondary battery, which includes the aforementioned electrode assembly 001 and electrolyte, wherein the electrode assembly 001 is immersed in the electrolyte.

[0047] The electrolyte plays a crucial role in transporting lithium ions and electrons, ensuring the formation of pathways within the electrochemical device. During use, the electrode assembly 001 needs to be completely immersed in the electrolyte. This application does not limit the electrolyte; any electrolyte that meets the objectives of this application is acceptable.

[0048] The secondary battery of this application can be used in any electronic device known in the prior art. In some embodiments, the secondary battery of this application can be used in, but is not limited to, laptops, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, household large-capacity batteries, and lithium-ion capacitors, etc.

[0049] Accordingly, this application also provides a method for preparing the electrode assembly 001, which can be used to manufacture the electrode assembly 001 provided in the above embodiments. The following will describe in detail a method for manufacturing the electrode assembly 001 provided in another embodiment of this application with reference to the accompanying drawings. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments; detailed descriptions will not be repeated below.

[0050] First, an active layer is coated on the surface of the current collector to obtain a large electrode 100. Then, the electrode 100 is cut at predetermined intervals to form smaller electrode pieces 100. Finally, spacer tape 200 is applied to the edge of the electrode 100 along a direction perpendicular to the coating direction.

[0051] In other embodiments of this application, to improve production efficiency, the same spacer tape 200 is used to attach two adjacent small electrode pieces 100, and then the spacer tape 200 is cut, such as... Figure 4 As shown. Because the spacer tape 200 is cut during the manufacturing process, the spacer tape 200 applied at this time is slightly different from the spacer tape 200 in the finished electrode assembly 001. This spacer tape 200 includes two coated areas 210 and one uncoated area 220. The two coated areas 210 are located on opposite sides of the uncoated area 220, as shown. Figure 5 As shown, during cutting, the cutting is performed along the non-adhesive area 220, and two electrode sheets 100 with spacer tape 200 attached can be obtained in one cut. Of course, in some other embodiments of this application, the spacer tape 200 can also be attached to the large electrode sheet 100 before cutting, which can further improve production efficiency.

[0052] After attaching spacer tape 200 to electrode 100, electrode 100 and separator film are stacked in sequence to form electrode assembly 001; wherein electrode 100 is an alternating arrangement of positive electrode and negative electrode.

[0053] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. An electrode assembly, characterized in that, include: An electrode and a separator are stacked together. The edges of the electrode are bonded with spacer tape, which is located between the electrode and the separator, and a portion of the spacer tape is bonded to the electrode. The spacer tape includes a non-adhesive area and an adhesive-coated area for bonding. The adhesive-coated area is located on the surface of the electrode and is bonded to the electrode. The non-adhesive area extends outward relative to the electrode.

2. The electrode assembly according to claim 1, characterized in that, The width of the adhesive coating area is 0.5mm to 5mm.

3. The electrode assembly according to claim 1, characterized in that, The width of the glue-free area is 0.5mm to 5mm.

4. The electrode assembly according to claim 1, characterized in that, The spacer tape includes a base film layer, and a portion of the base film layer near the surface of the electrode is provided with an adhesive layer; the portion of the spacer tape with the adhesive layer is the adhesive-coated area, and the portion of the spacer tape without the adhesive layer is the adhesive-free area.

5. The electrode assembly according to claim 1, characterized in that, The thickness of the spacer tape is 10μm to 50μm.

6. The electrode assembly according to claim 1, characterized in that, The electrode includes a current collector, and at least one surface of the current collector is provided with an active layer.

7. The electrode assembly according to claim 1 or 6, characterized in that, The thickness of the electrode is 50μm~300μm.

8. The electrode assembly according to claim 1 or 6, characterized in that, The electrode includes a positive electrode and a negative electrode, and the positive electrode and the negative electrode are arranged alternately in sequence; the number of positive electrode is not less than two.

9. The electrode assembly according to claim 1, characterized in that, The thickness of the isolation membrane is 1μm to 50μm.

10. A secondary battery, characterized in that, It includes an electrolyte and an electrode assembly as described in any one of claims 1 to 9, wherein the electrode assembly is immersed in the electrolyte.

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