Electrode sheet, battery cell, battery, and electric device

Abstract

An electrode sheet (7), a battery cell (5), a battery, and an electric device (6). The electrode sheet (7) comprises a composite current collector (72) and an electrode film layer (71) provided on at least one side of the composite current collector (72), the composite current collector (72) comprises a support layer (721) and a conductive composite layer (722) stacked on at least one side of the support layer (721), the conductive composite layer (722) comprises a metal layer, the surface of the conductive composite layer (722) facing the electrode film layer (71) on the same side is provided with a plurality of first recessed portions (723), the electrode film layer (71) comprises an electrode active material, and at least some of the first recessed portions (723) are embedded with an electrode active material. Applying the electrode sheet (7) to a battery can improve the cycle performance of the battery.

Description

Electrode plates, battery cells, batteries and electrical devices

[0001] Cross-references

[0002] This application refers to Chinese Patent Application No. 202420455444.3 filed on March 8, 2024, entitled “Electrode Plate, Battery Cell, Battery and Electrical Device,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to an electrode plate, a battery cell, a battery, and an electrical device. Background Art

[0004] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0005] Secondary batteries rely on the intercalation and deintercalation of active ions between the positive and negative electrodes to charge and discharge. They offer outstanding advantages such as high operating voltage, no memory effect, and minimal environmental pollution. Consequently, they are widely used in electric vehicles, power tools, military equipment, aerospace, and other fields. As the application of secondary batteries expands, the requirements for their cycle performance are also becoming increasingly stringent. Improving the cycle performance of secondary batteries is a pressing technical challenge.

[0006] Summary of the Invention

[0007] The present application provides an electrode plate, a battery cell, a battery and an electrical device to improve the cycle performance of the battery.

[0008] In a first aspect of the present application, an electrode plate is provided, which includes a composite current collector and an electrode film layer arranged on at least one side of the composite current collector, the composite current collector includes a support layer and a conductive composite layer stacked on at least one side of the support layer, the conductive composite layer includes a metal layer, and the surface of the conductive composite layer facing the electrode film layer on the same side has multiple first recesses, the electrode film layer contains electrode active material, and at least part of the first recesses is embedded with the electrode active material.

[0009] The design of multiple first recessed portions and at least part of the first recessed portions embedded with electrode active materials can increase the friction between the conductive composite layer and the electrode film layer on the same side, thereby effectively improving the adhesion between the conductive composite layer and the electrode film layer, reducing the risk of peeling between the electrode film layer and the conductive composite layer during the battery cycle, and at the same time, improving the electron conductivity between the electrode film layer and the composite current collector when the first recessed portion penetrates the metal layer, thereby effectively improving the cycle performance of the battery.

[0010] In some embodiments, the volume average particle size Dv50 of the electrode active material is less than or equal to the average depth of the first recess. This allows at least half of the electrode active material at the interface between the electrode film layer and the composite current collector to be embedded within the first recess, further enhancing the adhesion between the conductive composite layer and the electrode film layer, reducing the risk of delamination between the electrode film layer and the conductive composite layer during battery cycling, and thereby further improving the battery's cycling performance.

[0011] In some embodiments, the maximum particle size of the electrode active material is less than or equal to the average depth of the first recessed portion. This allows the strength of the composite current collector to be within a reasonable range, which is beneficial for improving the cycle performance of the battery.

[0012] In some embodiments, the volume average particle size Dv50 of the electrode active material is 5 μm to 12 μm.

[0013] In some embodiments, on the surface of the conductive composite layer away from the support layer, the ratio of the total area of ​​the first recessed portions to the area of ​​the conductive composite layer is 0.5 to 0.8. This can further enhance the adhesion between the conductive composite layer and the electrode film layer, reducing the risk of delamination between the electrode film layer and the conductive composite layer during battery cycling, thereby further improving the battery's cycling performance.

[0014] In some embodiments, at the location of the first recessed portion in at least a portion of the conductive composite layer, a convex portion corresponding to the first recessed portion is provided on the surface of the conductive composite layer facing the support layer, and a second recessed portion is provided on the surface of the support layer facing the conductive composite layer to accommodate the convex portion. This effectively improves the peeling force between the support layer and the conductive composite layer of the composite current collector, reduces the corrosion effect of the electrolyte on the metal layer in the conductive composite layer, and improves the composite current collector's resistance to electrolyte corrosion and its current carrying capacity, thereby further improving the battery's cycling performance.

[0015] In some embodiments, the conductive composite layer further includes an adhesive layer disposed between the metal layer and the support layer on at least one side. This improves the peeling force between the support layer and the conductive composite layer, reduces the corrosion rate of the metal layer by hydrohalic acid in the electrolyte, and further improves the flow capacity of the composite current collector.

[0016] In some embodiments, the conductive composite layer further includes a protective layer disposed on one or both surfaces of the metal layer along the thickness direction of at least one side. The protective layer can further reduce the corrosion rate of the metal layer by hydrohalic acid in the electrolyte, thereby further improving the flow capacity of the composite current collector.

[0017] In some embodiments, the metal layer includes one or more of an aluminum metal layer, a nickel metal layer, an aluminum alloy layer, and a nickel alloy layer.

[0018] In a second aspect of the present application, a battery cell is provided, which includes the electrode plate described in the first aspect of the present application.

[0019] The battery cell of the present application includes the electrode sheet provided in the present application, and thus has at least the same advantages as the electrode sheet.

[0020] In some embodiments, the battery cell includes a housing for housing an electrode assembly.

[0021] In some embodiments, the housing is square in shape, and comprises a shell and at least one end cover, wherein the shell has an opening at only one end, and the end cover covers the opening; or

[0022] Both ends of the shell have openings, and the two end covers cover the two openings respectively.

[0023] In some embodiments, the shell is a soft package structure, and the shell includes an aluminum-plastic film shell.

[0024] In some embodiments, the housing is shaped like a cylinder, and includes a shell and at least one end cover, wherein the end cover covers an opening of the shell, and an outer diameter of the cylinder is greater than or equal to 30 mm.

[0025] In a third aspect of the present application, a battery is provided, which includes one or more battery cells described in the second aspect of the present application.

[0026] The battery of the present application includes the battery cell provided by the present application, and thus has at least the same advantages as the battery cell.

[0027] In a fourth aspect of the present application, an electrical device is provided, which includes the battery cell described in the second aspect of the present application and at least one of the batteries provided in the third aspect of the present application.

[0028] The electric device of the present application includes at least one of the battery cell and the battery provided in the present application, and thus has at least the same advantages as the battery cell or the battery.

[0029] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered as limiting the scope of the disclosed application, the embodiments or examples currently described, and any of the best modes currently understood for these applications. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the accompanying drawings:

[0031] FIG1 is a schematic structural diagram of an electrode plate according to an embodiment of the present application.

[0032] FIG2 is a schematic structural diagram of a composite current collector in an electrode plate according to an embodiment of the present application shown in FIG1 .

[0033] FIG3 is a schematic structural diagram of an electrode plate according to another embodiment of the present application.

[0034] FIG4 is an exploded view of the composite current collector in the electrode sheet according to another embodiment of the present application shown in FIG3 .

[0035] FIG5 is an enlarged view of position A in FIG4 .

[0036] FIG6 is a schematic diagram of a battery cell according to an embodiment of the present application.

[0037] FIG. 7 is an exploded view of the battery cell shown in FIG. 6 according to an embodiment of the present application.

[0038] FIG8 is a schematic diagram of a battery module according to an embodiment of the present application.

[0039] FIG9 is a schematic diagram of a battery pack according to an embodiment of the present application.

[0040] FIG10 is an exploded view of the battery pack shown in FIG9 according to an embodiment of the present application.

[0041] FIG11 is a schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0042] Description of reference numerals:

[0043] 1. Battery pack; 2. Upper case; 3. Lower case; 4. Battery module; 5. Battery cell; 51. Housing; 52. Electrode assembly; 53. Cover plate; 6. Electrical device; 7. Electrode pole piece; 71. Electrode film layer; 72. Composite current collector; 721. Support layer; 722. Conductive composite layer; 723. First recessed portion; 724. Protrusion; 725. Second recessed portion. DETAILED DESCRIPTION

[0044] Below, some embodiments of the electrode plates, battery cells, batteries, and electrical devices of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0045] " scope " disclosed in the present application can be limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and any end value can be included or not included independently, and can be arbitrarily combined, that is, any lower limit can form a scope with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 listed, and if the maximum range value 3,4 and 5 are also listed, then the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for a combination of these values. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0046] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0047] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0048] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0049] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0050] In this application, open technical features or technical solutions described with words such as "contain," "include," and "includes" do not exclude additional members beyond the listed members unless otherwise specified, and can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions that include additional members beyond the listed members. For example, if A includes a1, a2, and a3, it may or may not include other members unless otherwise specified. This can be regarded as providing both the feature or solution of "A consists of a1, a2, and a3" and the feature or solution of "A includes not only a1, a2, and a3, but also other members."

[0051] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0052] One embodiment of the present application provides an electrode plate, which includes a composite current collector and an electrode film layer arranged on at least one side of the composite current collector. The composite current collector includes a support layer and a conductive composite layer stacked on at least one side of the support layer. The conductive composite layer includes a metal layer. The surface of the conductive composite layer facing the electrode film layer on the same side has multiple first recesses. The electrode film layer contains electrode active material, and at least part of the first recesses is embedded with the electrode active material.

[0053] In the above embodiment, the design of multiple first recessed portions and at least part of the first recessed portions embedded with electrode active materials can increase the friction between the conductive composite layer and the electrode film layer on the same side, thereby effectively improving the adhesion between the conductive composite layer and the electrode film layer, reducing the risk of peeling between the electrode film layer and the conductive composite layer during the battery cycle, and at the same time, improving the electron conduction ability between the electrode film layer and the composite current collector when the first recessed portion penetrates the metal layer, thereby effectively improving the cycle performance of the battery.

[0054] It should be noted that the electrode sheet can be a positive electrode sheet or a negative electrode sheet. When the electrode sheet is a positive electrode sheet, the electrode film layer is a positive electrode film layer and the electrode active material is a positive electrode active material. When the electrode sheet is a negative electrode sheet, the electrode film layer is a negative electrode film layer and the electrode active material is a negative electrode active material.

[0055] In the present application, the support layer may be in contact with the metal layer; or the support layer may be in contact with other layers in the conductive composite layer except the metal layer.

[0056] It is understandable that the bottom of the first recessed portion may be located in the conductive composite layer, for example, in the metal layer or in other layers of the conductive composite layer except the metal layer; or the bottom of the first recessed portion may pass through the metal layer and be located in the supporting layer.

[0057] Figure 1 is a schematic diagram of the structure of an exemplary electrode plate, and Figure 2 is a schematic diagram of the structure of a composite current collector in the electrode plate of Figure 1. Referring to Figures 1 and 2, the electrode plate 7 includes a composite current collector 72 and electrode film layers 71 disposed on both sides of the composite current collector 72. The composite current collector 72 includes a support layer 721 and a conductive composite layer 722 stacked on both sides of the support layer 721. The conductive composite layer 722 includes a metal layer. The surface of the conductive composite layer 722 facing the same side of the electrode film layer 71 has a plurality of first recesses 723. The electrode film layer 71 contains an electrode active material, and at least a portion of the first recesses 723 are embedded with the electrode active material. Such a design can increase the friction between the conductive composite layer 722 and the electrode film layer 71 on the same side, thereby effectively improving the adhesion between the conductive composite layer 722 and the electrode film layer 71, and reducing the risk of peeling between the electrode film layer 71 and the conductive composite layer 722 during the battery cycle. At the same time, it can improve the electronic conductivity between the electrode film layer 71 and the composite current collector 72 when the first recessed portion 723 penetrates the metal layer, thereby effectively improving the cycle performance of the battery.

[0058] In some embodiments, the volume average particle size Dv50 of the electrode active material is less than or equal to the average depth of the first recess. In the present application, Dv50 refers to the particle size corresponding to when the cumulative particle size distribution number of the particles reaches 50% in the volume cumulative distribution curve. Its physical meaning is that particles with a particle size smaller than (or larger than) it account for 50%. The above embodiment controls the relationship between the volume average particle size Dv50 of the electrode active material and the average depth of the first recess, so that at least half of the electrode active material at the interface between the electrode film layer and the composite current collector can be embedded in the first recess, further improving the bonding force between the conductive composite layer and the electrode film layer, reducing the risk of peeling between the electrode film layer and the conductive composite layer during the battery cycle, thereby further improving the battery cycle performance.

[0059] In the present application, the volume average particle size Dv50 of the electrode active material is measured with reference to GB / T 19077-2016 particle size distribution laser diffraction method using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd., UK.

[0060] In this application, the average depth of the first recessed portion is tested using the following method:

[0061] 1. Sample Preparation: a. Randomly select an electrode sheet, cut it into strips approximately 5 mm wide, and soak it in liquid nitrogen for 10 minutes. b. Remove the strip with tweezers and quickly break it with a knife, forming a cross section perpendicular to its length. With the non-contact blade facing upward, attach it to an A4 paper for later use. c. Use conductive adhesive to attach the cut section to a long sample stage, with the cut section slightly protruding (<1 mm) from the edge of the stage. Finally, place the strip upright on the scanning electron microscope (SEM) specimen holder.

[0062] 2. Parameter settings: The scanning electron microscope mode was In-lens, the voltage was 10 kilovolts (kV), the aperture was 30 micrometers (μm), and the working distance was 4.5 mm;

[0063] 3. Test process: Use a magnification of about 3K to find the concave parts in the electrode plate, take several pictures at magnifications of 30K, 10K, and 5K (1K=1000), randomly select the first concave parts in 12 positions, measure the depth of each first concave part, and then take the average value to get the average depth of the first concave parts.

[0064] In some embodiments, the maximum particle size of the electrode active material is less than or equal to the average depth of the first recessed portion. This allows the strength of the composite current collector to be within a reasonable range, which is beneficial for improving the cycle performance of the battery.

[0065] Specifically, an SEM image of the electrode active material in the electrode film layer is taken using an SEM, and then the longest diameter of the electrode active material is measured to obtain the maximum particle size of the electrode active material.

[0066] Furthermore, the volume average particle size Dv50 of the electrode active material is 5 μm to 12 μm. It is understood that the volume average particle size Dv50 of the electrode active material includes but is not limited to: 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, and 12 μm.

[0067] In some embodiments, on the surface of the conductive composite layer away from the support layer, the ratio of the total area of ​​the first recessed portions to the area of ​​the conductive composite layer is 0.5 to 0.8. This can further enhance the adhesion between the conductive composite layer and the electrode film layer, reducing the risk of delamination between the electrode film layer and the conductive composite layer during battery cycling, thereby further improving the battery's cycling performance. It is understood that the ratio of the total area of ​​the first recessed portions to the area of ​​the conductive composite layer includes, but is not limited to, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, and 0.8.

[0068] It should be noted that the total area of ​​the first recessed portions refers to the total area of ​​the first recessed portions in a cross-section of the conductive composite layer away from the support layer. The area of ​​the conductive composite layer refers to the area of ​​the conductive composite layer in a cross-section of the conductive composite layer away from the support layer.

[0069] In the present application, the total area of ​​the first recessed portions and the area of ​​the conductive composite layer on the surface away from the support layer are tested using the following method: randomly select three electrode plates with a length of 2 mm and a width of 2 mm, use N-methylpyrrolidone (NMP) to wash away the electrode film layer on the electrode plates, and then use SEM to measure the area of ​​the first recessed portions. The average value is then taken to obtain the total area of ​​the first recessed portions on the surface away from the support layer. Use a ruler to measure the length and width of the conductive composite layer in the three electrode plates, calculate the area of ​​the conductive composite layer, and then take the average value of the area of ​​the conductive composite layer to obtain the area of ​​the conductive composite layer on the surface away from the support layer.

[0070] Figure 3 is a schematic diagram of the structure of an electrode plate as another example, and Figure 4 is a schematic diagram of the structure of a composite current collector in the electrode plate of Figure 3. Referring to Figures 3 and 4, the electrode plate 7 includes a composite current collector 72 and electrode film layers 71 disposed on both sides of the composite current collector 72. The composite current collector 72 includes a support layer 721 and a conductive composite layer 722 stacked on both sides of the support layer 721. The conductive composite layer 722 includes a metal layer. The surface of the conductive composite layer 722 facing the same side of the electrode film layer 71 has a plurality of first recesses 723. The electrode film layer 71 contains electrode active material, and at least some of the first recesses 723 are embedded with the electrode active material.

[0071] Figure 5 is an enlarged view of position A in Figure 4 . Referring to Figures 4 and 5 , at the location of the first recess 723 in the conductive composite layer 722, a protrusion 724 corresponding to the first recess 723 is provided on the surface of the conductive composite layer 722 facing the support layer 721, and a second recess 725 is provided on the surface of the support layer 721 facing the conductive composite layer 722 to accommodate the protrusion 724. Thus, the protrusion 724 and the second recess 725 cooperate with each other to effectively enhance the peeling force between the support layer 721 and the conductive composite layer 722 of the composite current collector 72, mitigate the corrosion effect of the electrolyte on the metal layer in the conductive composite layer 722, and enhance the composite current collector 72's resistance to electrolyte corrosion and its current capacity, thereby further improving the battery's cycling performance.

[0072] In some embodiments, the conductive composite layer further includes an adhesive layer disposed between the metal layer and the support layer on at least one side. This improves the peeling force between the support layer and the conductive composite layer, reduces the corrosion rate of the metal layer by the hydrohalic acid in the electrolyte, and further improves the flow capacity of the composite current collector.

[0073] Furthermore, the thickness of the adhesive layer is 200 nm to 1500 nm. It is understood that the thickness of the adhesive layer includes but is not limited to: 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, 1200 nm, and 1500 nm.

[0074] In this application, the unit "nm" refers to nanometers.

[0075] In this application, the testing method for the thickness of each layer in the composite current collector is as follows: a cross-sectional sample of the composite current collector is prepared using a liquid nitrogen quenching method or an argon ion etching method, and the secondary electron phase morphology of the sample cross section is observed using a scanning electron microscope (1000 times to 30,000 times) to measure the thickness of each layer in the composite current collector.

[0076] Furthermore, the adhesive layer contains an adhesive, and the adhesive includes one or more of polyurethane, epoxy resin, polyacrylate, polyvinyl acetate, unsaturated polyester, phenolic resin, urea-formaldehyde resin, polyolefin resin, silicone resin, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, acrylic resin, polycarbonate and polyamide.

[0077] In some embodiments, the conductive composite layer further includes a protective layer, which is provided on one or both surfaces of the metal layer in the thickness direction of at least one side. The protective layer provided can further reduce the corrosion rate of the metal layer by the hydrohalic acid in the electrolyte, thereby further improving the flow capacity of the composite current collector. The protective layer can be provided between the metal layer and the electrode film layer, or the protective layer can be provided between the metal layer and the support layer. When an adhesive layer is provided between the metal layer and the support layer, the protective layer can be provided between the metal layer and the adhesive layer. It is understandable that the protective layer can be provided on any one surface in the thickness direction of the metal layer, or can be provided on both sides of the metal layer in the thickness direction. Thus, the corrosion rate of the metal layer by the hydrohalic acid in the electrolyte can be reduced, and the flow capacity of the composite current collector can be improved, thereby further improving the cycle performance of the battery.

[0078] Furthermore, the thickness of the protective layer on one side is 3 nm to 100 nm. This can further reduce the corrosion rate of the metal layer by the hydrohalic acid in the electrolyte, further improve the composite current collector's resistance to electrolyte corrosion and current flow capacity, and further enhance the battery's cycle performance. In some embodiments, the thickness of the protective layer on one side is 5 nm to 20 nm.

[0079] Furthermore, the protective layer contains metal oxides, which include one or more of aluminum oxide and aluminum fluoride, thereby further improving the cycle performance of the battery.

[0080] In some embodiments, the thickness of the conductive composite layer on one side is 500 nm to 4000 nm. It is understood that the thickness of the conductive composite layer on one side includes but is not limited to: 500 nm, 1000 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, and 4000 nm.

[0081] In some embodiments, the metal layer includes one or more of an aluminum metal layer, a nickel metal layer, an aluminum alloy layer, and a nickel alloy layer.

[0082] In some embodiments, the thickness of the support layer is 5 μm to 12 μm. It is understood that the thickness of the support layer includes but is not limited to: 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, and 12 μm.

[0083] In some embodiments, the material of the support layer includes one or more of a polymer material and a polymer-based composite material.

[0084] Furthermore, the polymer material includes one or more of polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polypropylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyformaldehyde, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfur nitride polymer materials, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, phenolic resin, their derivatives, their cross-linked products and their copolymers.

[0085] Furthermore, the polymer-based composite material includes a polymer material and an additive, wherein the additive includes one or more of a metal material and an inorganic non-metallic material. In some embodiments, the metal material includes one or more of aluminum, nickel, iron, silver, titanium, and alloys thereof. In some embodiments, the inorganic non-metallic material includes one or more of graphite, conductive carbon, aluminum oxide, silicon oxide, silicon carbide, and silicon dioxide.

[0086] In some embodiments, the electrode active material may penetrate at least one of the metal layer, the protective layer, and the adhesive layer. When the electrode active material penetrates the conductive composite layer, the first recessed portion at the corresponding position is formed by the conductive composite layer and the support layer.

[0087] In some embodiments, the thickness of the composite current collector is 6 μm to 20 μm. It is understood that the thickness of the composite current collector includes but is not limited to: 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, and 20 μm.

[0088] In some embodiments, the electrode plate is a positive electrode plate, the electrode film layer is a positive electrode film layer, and the electrode active material is a positive electrode active material.

[0089] Furthermore, the positive electrode active material may include positive electrode active materials for batteries known in the art. As non-limiting examples, the positive electrode active material may include one or more of the following materials: olivine-structured lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials; other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Non-limiting examples of olivine-structured lithium-containing phosphates may include, but are not limited to, one or more of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ) etc. Non-limiting examples of lithium nickel cobalt aluminum oxide may include LiNi 0.8 Co 0.15 Al 0.05 O2.

[0090] It is understandable that the battery will be accompanied by lithium (Li) deintercalation and consumption during the charge and discharge process, and the content of Li in the positive electrode plate is different when the battery is discharged to different states. In the list of positive electrode active materials in this application, unless otherwise specified, the content of Li is the initial state of the material. The positive electrode active material is applied to the positive electrode plate in the battery system, and after the charge and discharge cycle, the content of Li in the positive electrode active material contained in the plate will usually change. Among them, the content of Li can be measured by molar content, but is not limited to this. Regarding "the content of Li is the initial state of the material", the initial state of the material refers to the state before the material is added to the positive electrode slurry. It is understandable that new materials obtained by appropriate modification on the basis of the listed positive electrode active materials are also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to acceptable modification methods for positive electrode active materials, and non-limiting examples include coating modification.

[0091] In the examples of positive electrode active materials in this application, the oxygen (O) content is only a theoretical value. Lattice oxygen release will cause the molar content of oxygen to change, and the actual O content will fluctuate. The O content can be measured by molar content, but is not limited to this.

[0092] The weight ratio of the positive electrode active material in the positive electrode film layer is 80%-100%, based on the total weight of the positive electrode film layer.

[0093] Furthermore, the positive electrode film layer may optionally include a binder. As a non-limiting example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin. The weight ratio of the binder in the positive electrode film layer is 0-20%, based on the total weight of the positive electrode film layer.

[0094] Furthermore, the positive electrode film layer may optionally include a conductive agent. As non-limiting examples, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The weight ratio of the conductive agent in the positive electrode film layer is 0-20%, based on the total weight of the positive electrode film layer.

[0095] In some embodiments, the electrode plate is a negative electrode plate, the electrode film layer is a negative electrode film layer, and the electrode active material is a negative electrode active material.

[0096] Furthermore, the negative electrode active material may adopt negative electrode active materials for batteries that are well known in the art. As non-limiting examples, the negative electrode active material may include one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0097] The weight ratio of the negative electrode active material in the negative electrode film layer may be 70%-100%, based on the total weight of the negative electrode film layer.

[0098] Furthermore, the negative electrode film layer may optionally include a binder. The binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). The weight ratio of the binder in the negative electrode film layer may be 0-30%, based on the total weight of the negative electrode film layer.

[0099] Furthermore, the negative electrode film layer may optionally include a conductive agent. The conductive agent may be selected from one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. The weight ratio of the conductive agent in the negative electrode film layer may be 0-20%, based on the total weight of the negative electrode film layer.

[0100] Furthermore, the negative electrode film layer may optionally include other additives, such as a thickener (such as sodium carboxymethyl cellulose (CMC-Na)), etc. The weight ratio of the other additives in the negative electrode film layer may be 0-15%, based on the total weight of the negative electrode film layer.

[0101] Another embodiment of the present application provides a method for preparing the electrode sheet of the present application, which comprises the following steps:

[0102] forming a composite current collector including a first recessed portion;

[0103] An electrode slurry containing an electrode active material is placed on at least one side of the composite current collector and dried to form an electrode film layer, so that at least a portion of the first recessed portion is embedded with the electrode active material.

[0104] Therefore, the electrode plates can be prepared simply, which is conducive to the large-scale production of the electrode plates.

[0105] In some embodiments, the step of forming the composite current collector including the first recessed portion includes: pressing the composite current collector using a textured work roller, for example, using a convex-concave roller to form the first recessed portion.

[0106] Another embodiment of the present application provides another method for preparing the electrode sheet of the present application, which comprises the following steps:

[0107] Disposing an electrode slurry containing an electrode active material on at least one side of the composite current collector and drying the slurry to form an electrode film layer;

[0108] Pressure is applied to the electrode film layer to form a first recessed portion, and at least a portion of the first recessed portion is embedded with electrode active material.

[0109] Therefore, the electrode plates can be prepared simply, which is conducive to the large-scale production of the electrode plates.

[0110] In some embodiments, the step of applying pressure to the electrode film layer includes: performing a pressing process on the electrode film layer.

[0111] Yet another embodiment of the present application provides a battery cell, which includes the electrode plate described above.

[0112] The battery cell of the present application includes the electrode plate mentioned above, and thus has at least the same advantages as the electrode plate. It is understood that the electrode plate mentioned above can be a positive electrode plate or a negative electrode plate.

[0113] In some embodiments, a battery cell includes a housing for housing an electrode assembly. For example, the electrode assembly can be formed by winding or laminating the positive electrode sheet, negative electrode sheet, and separator from the battery cell. Therefore, the electrode assembly can include the electrode sheet described above.

[0114] In some embodiments, the housing is square in shape, and comprises a shell and at least one end cap, wherein the shell has an opening at only one end, and the end cap covers the opening; or

[0115] Both ends of the shell have openings, and the two end covers cover the two openings respectively.

[0116] In some embodiments, the shell is a soft package structure, and the material of the shell includes aluminum-plastic film.

[0117] In some embodiments, the housing is a soft package structure, and the housing includes an aluminum-plastic film housing.

[0118] In some embodiments, the outer shell is in the shape of a cylinder, and includes a shell and at least one end cover, the end cover covers the opening of the shell, and the outer diameter of the cylinder is greater than or equal to 30 mm.

[0119] Yet another embodiment of the present application provides a battery, which includes one or more battery cells described above.

[0120] In some embodiments, the battery comprises a secondary battery.

[0121] Typically, a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator. During the charge and discharge process of the battery, active ions are embedded and extracted back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through. At least one of the positive electrode sheet and the negative electrode sheet adopts the above-mentioned electrode sheet of the present application. The electrolyte has the function of conducting ions between the positive electrode sheet and the negative electrode sheet. The present application does not have any special restrictions on the type of electrolyte, which can be selected according to needs. For example, the electrolyte can be liquid, gel or all-solid.

[0122] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical and mechanical stability can be selected.

[0123] Furthermore, the material of the separator can include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0124] Furthermore, the thickness of the isolation film is 6 μm-40 μm, and can be optionally 12 μm-20 μm.

[0125] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a lamination process.

[0126] In some embodiments, the secondary battery may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0127] Furthermore, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. Alternatively, the outer packaging of the secondary battery can be a soft shell, such as a pouch-type soft shell. The soft shell can be made of plastic. Furthermore, non-limiting examples of plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0128] A secondary battery includes at least one battery cell. A secondary battery may include one or more battery cells.

[0129] In this application, unless otherwise specified, a "battery cell" refers to a basic unit that can achieve the mutual conversion of chemical energy and electrical energy. Further, generally speaking, it includes at least a positive electrode plate, a negative electrode plate, and an electrolyte. During the battery's charge and discharge process, active ions are embedded in and out of the positive and negative electrode plates. The electrolyte plays the role of conducting active ions between the positive and negative electrode plates.

[0130] The present application has no particular limitation on the shape of the battery cell, which can be cylindrical, square, or any other shape. For example, FIG6 shows a battery cell 5 with a square structure as an example.

[0131] In some embodiments, referring to Figure 7, the outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can be formed into an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and those skilled in the art can select according to actual needs.

[0132] The secondary battery may be a battery module 4 or a battery pack 1 .

[0133] A battery module includes at least one battery cell. The number of battery cells contained in a battery module can be one or more, and those skilled in the art can select an appropriate number based on the application and capacity of the battery module.

[0134] Figure 8 shows an example battery module 4. Referring to Figure 8 , within the battery module 4, multiple battery cells 5 may be arranged sequentially along the length of the battery module 4. Of course, they may also be arranged in any other manner. Furthermore, the multiple battery cells 5 may be secured together using fasteners.

[0135] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0136] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules. Those skilled in the art may select an appropriate number based on the application and capacity of the battery pack.

[0137] Figures 9 and 10 illustrate an example battery pack 1. Referring to Figures 9 and 10 , the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box comprises an upper case 2 and a lower case 3. The upper case 2 can be placed over the lower case 3 to form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0138] In addition, the present application also provides an electrical device, which includes the above-mentioned battery cell of the present application and at least one of the above-mentioned batteries of the present application.

[0139] The battery pack can be used as a power source or an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, and energy storage systems.

[0140] As the electrical device, a secondary battery can be selected according to its usage requirements.

[0141] Figure 11 shows an example of an electric device. The electric device 6 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the electric device's requirements for high power and high energy density of secondary batteries, a battery pack or battery module can be used.

[0142] Another example device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is generally required to be lightweight and thin, and may use a secondary battery as a power source.

[0143] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An electrode plate, comprising a composite current collector and an electrode film layer disposed on at least one side of the composite current collector, the composite current collector comprising a support layer and a conductive composite layer stacked on at least one side of the support layer, the conductive composite layer comprising a metal layer, the surface of the conductive composite layer facing the electrode film layer on the same side having a plurality of first recesses, the electrode film layer containing an electrode active material, and at least a portion of the first recesses being embedded with the electrode active material.

2. The electrode plate according to claim 1, wherein: The volume average particle size Dv50 of the electrode active material is ≤ the average depth of the first depressed portions.

3. The electrode plate according to claim 1 or 2, wherein: The maximum particle size of the electrode active material is less than or equal to the average depth of the first depressed portions.

4. The electrode plate according to any one of claims 1 to 3, wherein: The volume average particle size Dv50 of the electrode active material is 5 μm to 12 μm.

5. The electrode plate according to any one of claims 1 to 4, wherein: On a surface of the conductive composite layer away from the support layer, a ratio of the total area of ​​the first recessed portions to the area of ​​the conductive composite layer is 0.5 to 0.

8.

6. The electrode plate according to any one of claims 1 to 5, wherein: At the position of the first recessed portion of at least part of the conductive composite layer, a convex portion corresponding to the first recessed portion is provided on the surface of the conductive composite layer facing the support layer, and a second recessed portion for accommodating the recessed portion is provided on the surface of the support layer facing the conductive composite layer.

7. The electrode plate according to any one of claims 1 to 6, wherein: The conductive composite layer further includes a bonding layer, and the bonding layer is provided between the metal layer and the support layer on at least one side.

8. The electrode plate according to any one of claims 1 to 7, wherein: The conductive composite layer further includes a protective layer, and the protective layer is provided on one surface or both surfaces of the metal layer in a thickness direction on at least one side.

9. The electrode plate according to any one of claims 1 to 8, wherein: The metal layer includes one or more of an aluminum metal layer, a nickel metal layer, an aluminum alloy layer, and a nickel alloy layer.

10. A battery cell comprising the electrode sheet according to any one of claims 1 to 9.

11. The battery cell according to claim 10, wherein: The battery cell includes a housing for accommodating an electrode assembly.

12. The battery cell according to claim 11, wherein: The housing is square in shape, and comprises a shell and at least one end cover, wherein only one end of the shell has an opening, and the end cover covers the opening; or Both ends of the shell have openings, and the two end covers cover the two openings respectively.

13. The battery cell according to claim 11, wherein: The shell is a soft package structure, and the shell includes an aluminum-plastic film shell.

14. The battery cell according to claim 11, wherein The outer shell is in the shape of a cylinder and comprises a shell and at least one end cover, wherein the end cover covers the opening of the shell, and the outer diameter of the cylinder is greater than or equal to 30 mm. 15 . A battery comprising one or more battery cells according to claim 10 . 16 . An electrical device comprising at least one of the battery cell according to claim 10 and the battery according to claim 15 .

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