Electrode plate, battery monomer, battery and electric device

Abstract

The utility model relates to an electrode pole piece, a battery monomer, a battery and a power utilization device, the electrode pole piece comprises a composite current collector and an electrode film layer arranged on at least one side of the composite current collector, the composite current collector comprises a support layer and a conductive composite layer laminated on at least one side of the support layer, and the conductive composite layer comprises a metal layer. The surface, facing the electrode film layer on the same side, of the conductive composite layer is provided with a plurality of first sunken parts, the electrode film layer contains an electrode active material, and the electrode active material is embedded in at least part of the first sunken parts. When the electrode plate is applied to the battery, the cycle performance of the battery can be improved.

Description

Technical Field

[0001] 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

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] Secondary batteries rely on active ions to be inserted and removed back and forth between the positive and negative electrodes for charging and discharging. They have outstanding advantages such as high operating voltage, no memory effect, and low environmental pollution. Therefore, secondary batteries are widely used in electric vehicles, power tools, military equipment, aerospace and other fields. As the application scope of secondary batteries becomes wider and wider, the requirements for the cycle performance of secondary batteries are also getting higher and higher. How to improve the cycle performance of secondary batteries is a technical problem that needs to be solved urgently. Utility Model Content

[0004] The present application provides an electrode plate, a battery cell, a battery and an electrical device to improve the cycle performance of the battery.

[0005] 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 a plurality of first recessed portions, the electrode film layer contains an electrode active material, and at least part of the first recessed portions is embedded with the electrode active material.

[0006] 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, can improve 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 battery cycle performance.

[0007] 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 recessed portion. Thus, 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 recessed portion, 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.

[0008] 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. Thus, the strength of the composite current collector can be within a reasonable range, which is beneficial to improving the cycle performance of the battery.

[0009] In some embodiments, the volume average particle size Dv50 of the electrode active material is 5 μm to 12 μm.

[0010] 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. Thus, the bonding force between the conductive composite layer and the electrode film layer can be further improved, and the risk of peeling between the electrode film layer and the conductive composite layer during the battery cycle can be reduced, thereby further improving the battery cycle performance.

[0011] In some embodiments, 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 convex portion is provided on the surface of the support layer facing the conductive composite layer. Thus, the peeling force between the support layer and the conductive composite layer of the composite current collector can be effectively improved, the corrosion effect of the electrolyte on the metal layer in the conductive composite layer can be reduced, and the resistance of the composite current collector to electrolyte corrosion and the current carrying capacity can be improved, thereby further improving the cycle performance of the battery.

[0012] In some embodiments, the conductive composite layer further comprises an adhesive layer, and the adhesive layer is disposed between the metal layer and the support layer on at least one side, thereby improving the peeling force between the support layer and the conductive composite layer, reducing the corrosion rate of the metal layer by the hydrohalic acid in the electrolyte, and further improving the flow capacity of the composite current collector.

[0013] In some embodiments, the conductive composite layer further includes a protective layer, which is disposed on one or both surfaces of the metal layer in the thickness direction of at least one side. The protective layer 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.

[0014] 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.

[0015] A second aspect of the present application provides a battery cell, which includes the electrode plate described in the first aspect of the present application.

[0016] 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.

[0017] In some embodiments, the battery cell includes a housing for accommodating an electrode assembly.

[0018] In some embodiments, the housing is square in shape, and comprises a shell and at least one end cover, the shell has an opening at only one end, and the end cover covers the opening; or

[0019] Both ends of the shell have openings, and the two end covers cover the two openings respectively.

[0020] In some embodiments, the shell is a soft package structure, and the shell includes an aluminum-plastic film shell.

[0021] In some embodiments, the outer shell is in the shape of a cylinder, and the outer shell 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.

[0022] According to a third aspect of the present application, a battery is provided, which includes one or more battery cells as described in the second aspect of the present application.

[0023] 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.

[0024] A fourth aspect of the present application provides an electrical device comprising at least one of the battery cells described in the second aspect of the present application and the battery provided in the third aspect of the present application.

[0025] 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.

[0026] 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

[0027] In order to better describe and illustrate the embodiments or examples provided by the present application, reference may be made to one or more drawings. The additional details or examples used to describe the 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 of these applications currently understood. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0028] Figure 1 It is a schematic diagram of the structure of an electrode plate according to one embodiment of the present application.

[0029] Figure 2 yes Figure 1A schematic diagram of the structure of a composite current collector in an electrode plate according to one embodiment of the present application is shown.

[0030] Figure 3 It is a schematic diagram of the structure of an electrode plate according to another embodiment of the present application.

[0031] Figure 4 yes Figure 4 An exploded view of a composite current collector in an electrode plate according to another embodiment of the present application is shown.

[0032] Figure 5 yes Figure 4 Enlarged view of position A in the middle.

[0033] Figure 6 It is a schematic diagram of a battery cell according to an embodiment of the present application.

[0034] Figure 7 yes Figure 6 An exploded view of a battery cell according to an embodiment of the present application is shown.

[0035] Figure 8 is a schematic diagram of a battery module according to an embodiment of the present application.

[0036] Fig. 9 It is a schematic diagram of a battery pack according to one embodiment of the present application.

[0037] Fig.10 yes Fig.11 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0038] Fig.11 Schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0039] Description of reference numerals:

[0040] 1. Battery pack; 2. Upper box; 3. Lower box; 4. Battery module; 5. Battery cell; 51. Shell; 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

[0041] 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 drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are 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 descriptions 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.

[0042] "Scope" disclosed in the present application can be limited in the form of lower limit and upper limit, and a 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 a special range. The scope limited in this way can be including end values ​​or excluding end values, and any end value can be included or not included independently, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 listed, and if the maximum range values ​​3,4 and 5 are also listed, 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 real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer 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", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0043] In the present application, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0044] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0045] Reference to "embodiments" herein means 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 the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments. The "implementation methods" mentioned herein have a similar understanding.

[0046] In the description of the present 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 the present 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 the present application.

[0047] In this application, in the open technical features or technical solutions described by the words "contain", "include", "include", etc., if there is no other explanation, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2 and a3. If there is no other explanation, it may also include other members or may not include additional members. It 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".

[0048] 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.

[0049] 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 a plurality of first recessed portions, the electrode film layer contains electrode active material, and at least part of the first recessed portions is embedded with the electrode active material.

[0050] 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, can improve 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 battery cycle performance.

[0051] 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.

[0052] 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.

[0053] 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 penetrate the metal layer and be located in the supporting layer.

[0054] Figure 1 is a schematic diagram of the structure of an electrode plate as an example, Figure 2 yes Figure 1 Schematic diagram of the structure of the composite current collector in the electrode plate. Figure 1 and Figure 2 The electrode plate 7 includes a composite current collector 72 and an electrode film layer 71 arranged 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 electrode film layer 71 on the same side has a plurality of first recesses 723. The electrode film layer 71 contains an electrode active material, and at least part of the first recesses 723 are embedded with the electrode active material. With such a design, the friction between the conductive composite layer 722 and the electrode film layer 71 on the same side can be increased, thereby effectively improving the bonding force between the conductive composite layer 722 and the electrode film layer 71, reducing the risk of peeling between the electrode film layer 71 and the conductive composite layer 722 during the battery cycle, and at the same time, the electron conduction ability between the electrode film layer 71 and the composite current collector 72 can be improved when the first recess 723 penetrates the metal layer, thereby effectively improving the battery cycle performance.

[0055] In some embodiments, the volume average particle size Dv50 of the electrode active material is ≤ the average depth of the first recess. In the present application, Dv50 refers to the particle size corresponding to 50% of the cumulative particle size distribution number of the particles in the volume cumulative distribution curve. Its physical meaning is that the 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.

[0056] In the present application, the volume average particle size Dv50 of the electrode active material refers to the particle size distribution laser diffraction method of GB / T 19077-2016 and is measured using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer produced by Malvern Instruments Ltd., UK.

[0057] In this application, the average depth of the first recessed portion is tested using the following method:

[0058] 1. Sample preparation: a. Randomly select an electrode sheet, cut it into strips about 5 mm wide and soak it in liquid nitrogen for 10 minutes; b. Take out the strip with tweezers and quickly break it with a knife to form a cross section perpendicular to the length direction, and stick it on A4 paper with the non-contact blade facing up for later use; c. Cut the cross section and stick it on the long strip sample stage with conductive glue, with the cross section slightly protruding (<1mm) from the edge of the sample stage, and finally stand the strip on the scanning electron microscope (SEM) sample holder;

[0059] 2. Parameter settings: The scanning electron microscope mode is In-lens, the voltage is 10KV, the aperture is 30μm, and the working distance is 4.5mm;

[0060] 3. Test process: Use a magnification of about 3K to find the depressed parts in the electrode plate, take several pictures at magnifications of 30K, 10K, and 5K (1K=1000), randomly select the first depressed parts in 12 positions, measure the depth of each first depressed part, and then take the average value to get the average depth of the first depressed part.

[0061] 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. Thus, the strength of the composite current collector can be within a reasonable range, which is beneficial to improving the cycle performance of the battery.

[0062] Specifically, the maximum particle size of the electrode active material can be obtained by taking an SEM picture of the electrode active material in the electrode film layer using an SEM and then measuring the longest diameter of the electrode active material.

[0063] Further, 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, 12 μm.

[0064] In some embodiments, on the surface of the conductive composite layer away from the support layer, the ratio of the sum of the areas of the first recessed portions to the area of ​​the conductive composite layer is 0.5 to 0.8. Thus, the bonding force between the conductive composite layer and the electrode film layer can be further improved, and the risk of peeling between the electrode film layer and the conductive composite layer during the battery cycle can be reduced, thereby further improving the battery cycle performance. It can be understood that the ratio of the sum of the areas 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, 0.8.

[0065] It should be noted that the sum of the areas of the first recessed portions refers to the sum of the areas of the first recessed portions in a cross section with the surface of the conductive composite layer away from the support layer as the cross section. The area of ​​the conductive composite layer refers to the area of ​​the conductive composite layer in a cross section with the surface of the conductive composite layer away from the support layer as the cross section.

[0066] In the present application, the total area of ​​the first depression and the area of ​​the conductive composite layer on the surface away from the support layer are tested by the following method: randomly select 3 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 depression, and then take the average value to obtain the total area of ​​the first depression on the surface away from the support layer of the conductive composite layer. Use a ruler to measure the length and width of the conductive composite layer in the 3 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.

[0067] Figure 3 is a schematic diagram of the structure of an electrode plate as another example, Figure 4 yes Figure 3 Schematic diagram of the structure of the composite current collector in the electrode plate. Figure 3 and Figure 4The electrode plate 7 includes a composite current collector 72 and an electrode film layer 71 arranged 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 electrode film layer 71 on the same side has a plurality of first recesses 723. The electrode film layer 71 contains electrode active material, and at least part of the first recesses 723 are embedded with electrode active material.

[0068] Figure 5 yes Figure 4 See the enlarged view of position A in the figure. Figure 4 and Figure 5 , at the position of the first recessed portion 723 of the conductive composite layer 722, a convex portion 724 corresponding to the first recessed portion 723 is provided on the surface of the conductive composite layer 722 facing the support layer 721, and a second recessed portion 725 accommodating the convex portion 724 is provided on the surface of the support layer 721 facing the conductive composite layer 722. Thus, the convex portion 724 and the second recessed portion 725 can cooperate with each other to effectively improve the peeling force between the support layer 721 and the conductive composite layer 722 of the composite current collector 72, reduce the corrosion effect of the electrolyte on the metal layer in the conductive composite layer 722, and improve the resistance of the composite current collector 72 to electrolyte corrosion and the current capacity, thereby further improving the cycle performance of the battery.

[0069] In some embodiments, the conductive composite layer further includes an adhesive layer, which is disposed between the metal layer and the support layer on at least one side, thereby improving the peeling force between the support layer and the conductive composite layer, reducing the corrosion rate of the metal layer by the hydrohalic acid in the electrolyte, and further improving the flow capacity of the composite current collector.

[0070] Further, the thickness of the bonding layer is 200 nm to 1500 nm. It is understood that the thickness of the bonding layer includes but is not limited to: 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, 1200 nm, and 1500 nm.

[0071] In the present 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 by liquid nitrogen quenching or argon ion etching, and the secondary electron phase morphology of the cross-sectional sample is observed by scanning electron microscopy (1000 times-30000 times) to measure the thickness of each layer in the composite current collector.

[0072] Furthermore, the bonding layer contains a bonding agent, and the bonding agent 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.

[0073] In some embodiments, the conductive composite layer further includes a protective layer, and the protective layer is provided on one or both surfaces in the thickness direction of the metal layer on 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 a bonding layer is provided between the metal layer and the support layer, the protective layer can be provided between the metal layer and the bonding 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 the double-sided surfaces in the thickness direction of the metal layer. 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.

[0074] Furthermore, the thickness of the protective layer on one side is 3nm~100nm. Thus, the corrosion rate of the metal layer by the hydrohalic acid in the electrolyte can be further reduced, the resistance to electrolyte corrosion and the flow capacity of the composite current collector can be further improved, and the cycle performance of the battery can be further improved. Optionally, the thickness of the protective layer on one side is 5nm~20nm.

[0075] Furthermore, the protective layer contains metal oxides, and the metal oxides include one or more of aluminum oxide and aluminum fluoride, thereby further improving the cycle performance of the battery.

[0076] 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, 4000 nm.

[0077] 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.

[0078] 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.

[0079] In some embodiments, the material of the support layer includes one or more of a polymer material and a polymer-based composite material.

[0080] 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.

[0081] Further, the polymer-based composite material includes a polymer material and an additive, and the additive includes one or more of a metal material and an inorganic non-metal material. Optionally, the metal material includes one or more of aluminum, nickel, iron, silver, titanium and alloys thereof. Optionally, the inorganic non-metal material includes one or more of graphite, conductive carbon, aluminum oxide, silicon oxide, silicon carbide and silicon dioxide.

[0082] In some embodiments, the electrode active material may penetrate at least one of the metal layer, the protective layer, and the bonding 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.

[0083] 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.

[0084] 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.

[0085] Further, the positive electrode active material may include a positive electrode active material for a battery known in the art. As a non-limiting example, the positive electrode active material may include one or more of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, 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 lithium-containing phosphates with an olivine structure 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.

[0086] It is understandable that the battery will be accompanied by lithium (Li) deintercalation and consumption during the charging and discharging process, and the content of Li in the positive electrode plate is different when the battery is discharged to different states. In the enumeration 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 usually changes. 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 the new material obtained by appropriate modification on the basis of the listed positive electrode active materials is also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to the acceptable modification method for the positive electrode active material, and non-limiting examples include coating modification.

[0087] In the list of positive electrode active materials in this application, the content of oxygen (O) is only a theoretical state value. The release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual content of O will fluctuate. Among them, the content of O can be measured by molar content, but is not limited to this.

[0088] 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.

[0089] Further, the positive electrode film layer may also 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.

[0090] Further, the positive electrode film layer may also optionally include a conductive agent. As a non-limiting example, 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.

[0091] 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.

[0092] Furthermore, the negative electrode active material may adopt the negative electrode active material for batteries known in the art. As a non-limiting example, 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] Another embodiment of the present application provides a method for preparing the electrode sheet of the present application, which comprises the following steps:

[0098] forming a composite current collector including a first recessed portion;

[0099] An electrode slurry containing an electrode active material is disposed 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.

[0100] Therefore, the electrode plates can be prepared simply, which is beneficial to the large-scale production of the electrode plates.

[0101] In some embodiments, the step of forming the composite current collector including the first recessed portion includes: using a textured working roller to press the composite current collector. For example, a concave-convex roller may be used to press the composite current collector to form the first recessed portion.

[0102] Another embodiment of the present application provides another method for preparing the electrode sheet of the present application, which comprises the following steps:

[0103] 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;

[0104] A 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 an electrode active material.

[0105] Therefore, the electrode plates can be prepared simply, which is beneficial to the large-scale production of the electrode plates.

[0106] In some embodiments, the step of applying pressure to the electrode film layer includes: performing a pressing process on the electrode film layer.

[0107] Another embodiment of the present application provides a battery cell, which includes the electrode plate mentioned above in the present application.

[0108] The battery cell of the present application includes the electrode plate of the present application, and thus has at least the same advantages as the electrode plate. It can be understood that the electrode plate can be a positive electrode plate or a negative electrode plate.

[0109] In some embodiments, the battery cell includes a housing for accommodating an electrode assembly. Exemplarily, the electrode assembly may be formed by a positive electrode sheet, a negative electrode sheet, and a separator in the battery cell through a winding process or a lamination process. Therefore, the electrode assembly may include the electrode sheet described above in the present application.

[0110] In some embodiments, the outer shell is square in shape, and comprises a shell and at least one end cover, the shell has an opening at only one end, and the end cover covers the opening; or

[0111] Both ends of the shell have openings, and the two end covers cover the two openings respectively.

[0112] In some embodiments, the shell is a soft package structure, and the material of the shell includes aluminum-plastic film.

[0113] In some embodiments, the shell is a soft package structure, and the shell includes an aluminum-plastic film shell.

[0114] In some embodiments, the outer shell is in the shape of a cylinder, and the outer shell 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.

[0115] Yet another embodiment of the present application provides a battery, which includes one or more of the above-mentioned battery cells of the present application.

[0116] In some embodiments, the battery comprises a secondary battery.

[0117] Typically, a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator. During the battery charge and discharge process, active ions are embedded and removed 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, which mainly plays the role of preventing the positive and negative electrodes from short-circuiting, and at the same time allows 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.

[0118] 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 stability and mechanical stability can be selected.

[0119] Furthermore, the material of the isolation membrane may include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane may be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0120] Furthermore, the thickness of the isolation film is 6 μm-40 μm, and can be optionally 12 μm-20 μm.

[0121] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0122] In some embodiments, the secondary battery may include an outer package, which may be used to encapsulate the electrode assembly and the electrolyte.

[0123] Further, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the secondary battery can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic, and further, non-limiting examples of plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0124] The secondary battery includes at least one battery cell. The secondary battery may include one or more battery cells.

[0125] In this application, unless otherwise specified, "battery cell" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and further, generally speaking, at least includes a positive electrode sheet, a negative electrode sheet and an electrolyte. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting active ions between the positive electrode sheet and the negative electrode sheet.

[0126] The present application has no particular limitation on the shape of the battery cell, which may be cylindrical, square or any other shape. Figure 6 The battery cell 5 is a square structure as an example.

[0127] In some embodiments, reference Figure 7 , the outer packaging may include a shell 51 and a cover plate 53. Among them, 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 form 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.

[0128] The secondary battery may be a battery module 4 or a battery pack 1 .

[0129] The battery module includes at least one battery cell. The number of battery cells contained in the battery module can be one or more, and those skilled in the art can select a suitable number according to the application and capacity of the battery module.

[0130] Figure 8 4 is an example of a battery module. Figure 8 In the battery module 4, the plurality of battery cells 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of battery cells 5 may be fixed by fasteners.

[0131] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0132] In some embodiments, the battery modules described above may also be assembled into a battery pack. The number of battery modules contained in the battery pack may be one or more. Those skilled in the art may select a suitable number according to the application and capacity of the battery pack.

[0133] Fig. 9 and Fig.101 is a battery pack 1 as an example. Fig. 9 and Fig.10 The battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0134] 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.

[0135] The battery pack can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but is not limited thereto.

[0136] As the electrical device, a secondary battery can be selected according to its usage requirements.

[0137] Fig.11 The power consumption device 6 is used as an example. The power consumption device 6 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the power consumption device's requirements for high power and high energy density of secondary batteries, a battery pack or a battery module can be used.

[0138] Another example of a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be light and thin, and a secondary battery may be used as a power source.

[0139] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An electrode plate, characterized in that: It 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 a plurality of first recessed portions, the electrode film layer contains electrode active material, and at least part of the first recessed portions is embedded with the electrode active material.

2. The electrode plate according to claim 1, characterized in that: 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 2, characterized in that: 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, characterized in that: 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 3, characterized in that: On a surface of the conductive composite layer away from the support layer, a ratio of a total area of ​​the first recessed portions to an area of ​​the conductive composite layer is 0.5-0.

8.

6. The electrode plate according to any one of claims 1 to 3, characterized in that: At the position of the first recessed portion of at least part of the conductive composite layer, a surface of the conductive composite layer facing the support layer is provided with a convex portion corresponding to the first recessed portion, and a surface of the support layer facing the conductive composite layer is provided with a second recessed portion accommodating the convex portion.

7. The electrode plate according to any one of claims 1 to 3, characterized in that: The conductive composite layer further includes a bonding layer, and the bonding layer is arranged 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 3, characterized in that: The conductive composite layer further includes a protective layer, and the protective layer is disposed on one surface or two surfaces of the metal layer in a thickness direction of at least one side.

9. The electrode plate according to any one of claims 1 to 3, characterized in that: 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, characterized in that: The electrode plate comprises the electrode plate according to any one of claims 1 to 9.

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

12. The battery cell according to claim 11, characterized in that: The outer shell is in a square 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, characterized in that: The shell is a soft package structure, and the shell includes an aluminum-plastic film shell.

14. The battery cell according to claim 11, characterized in that: 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 an opening of the shell, and an outer diameter of the cylinder is greater than or equal to 30 mm.

15. A battery, characterized in that: Comprising one or more battery cells according to any one of claims 10 to 14.

16. An electrical device, characterized in that: The invention comprises at least one of the battery cell according to any one of claims 10 to 14 and the battery according to claim 15.

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