Current collector and battery having the same

Abstract

The utility model provides a kind of current collector and battery with it, wherein, current collector, comprising: metal layer structure;Coated carbon layer structure is set on metal layer structure;Multiple rough concave structures are spacedly set on coated carbon layer structure, and the maximum depth of each rough concave structure is less than the thickness of coated carbon layer structure.The technical scheme of the application effectively solves the problem that the dry method current collector and pole piece are easily adhered with low adhesion or appear the problem of dropping material in the related art.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a current collector and a battery having the same. Background Technology

[0002] In the field of lithium battery manufacturing, dry process technology is gradually gaining attention as an environmentally friendly and efficient production method. Compared with the traditional wet process, the dry process avoids the use of organic solvents, which not only reduces production costs and environmental pollution, but also improves production safety.

[0003] In related technologies, dry current collectors can be combined with electrode sheets, but during the combination process, there are issues such as low adhesion or material shedding. Utility Model Content

[0004] The main objective of this invention is to provide a current collector and a battery having the same, in order to solve the problem of low adhesion or material shedding that easily occurs when dry current collectors are combined with electrode sheets in related technologies.

[0005] To achieve the above objectives, according to one aspect of the present invention, a current collector is provided, comprising: a metal layer structure; a carbon-coated layer structure disposed on the metal layer structure; and a plurality of rough recessed structures disposed at intervals on the carbon-coated layer structure, wherein the maximum depth of each rough recessed structure is less than the thickness of the carbon-coated layer structure.

[0006] According to another aspect of the present invention, a battery is provided, including a cell, the cell including a current collector and an active material layer coated on the surface of the current collector, the current collector being the aforementioned current collector.

[0007] The present invention employs a carbon coating layer structure disposed on a metal layer structure, with multiple rough, recessed structures spaced apart on the carbon coating layer structure. The maximum depth of each rough, recessed structure is less than the depth of the carbon coating layer structure. Through this arrangement, the rough, recessed structures increase the surface roughness of the carbon coating layer structure, thereby increasing the contact area and mechanical interlocking force between the adhesive and the current collector, and effectively improving the bonding effect when the current collector and the electrode are combined. Therefore, the technical solution of this application effectively solves the problem of low adhesion or material shedding that easily occurs when dry current collectors are combined with electrodes in related technologies. Attached Figure Description

[0008] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0009] Figure 1A three-dimensional structural schematic diagram of a current collector according to a first embodiment of the present invention is shown;

[0010] Figure 2 It shows Figure 1 A top view of the current collector;

[0011] Figure 3 It shows Figure 1 A cross-sectional schematic diagram of the current collector;

[0012] Figure 4 A three-dimensional structural schematic diagram of a second embodiment of the current collector according to the present invention is shown;

[0013] Figure 5 It shows Figure 4 A top view of the current collector;

[0014] Figure 6 It shows Figure 4 A cross-sectional schematic diagram of the current collector;

[0015] Figure 7 A three-dimensional structural schematic diagram of a current collector according to a third embodiment of the present invention is shown;

[0016] Figure 8 It shows Figure 7 A top view of the current collector;

[0017] Figure 9 A three-dimensional structural schematic diagram of a current collector according to a fourth embodiment of the present invention is shown;

[0018] Figure 10 It shows Figure 9 A top view of the current collector.

[0019] The above figures include the following reference numerals:

[0020] 10. Metal layer structure; 20. Carbon coating layer structure; 30. Rough and recessed structure. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0024] like Figures 1 to 3 As shown, in Embodiment 1, the current collector includes: a metal layer structure 10, a carbon-coated layer structure 20, and a plurality of rough recessed structures 30. The carbon-coated layer structure 20 is disposed on the metal layer structure 10. The plurality of rough recessed structures 30 are disposed at intervals on the carbon-coated layer structure 20, and the maximum depth of each rough recessed structure 30 is less than the thickness of the carbon-coated layer structure 20.

[0025] In the technical solution of Embodiment 1, the carbon coating layer structure 20 is disposed on the metal layer structure 10, and multiple rough recessed structures 30 are spaced apart on the carbon coating layer structure 20. The maximum depth of each rough recessed structure 30 is less than the depth of the carbon coating layer structure 20. Through the above arrangement, the rough recessed structures 30 can increase the surface roughness of the carbon coating layer structure 20, thereby increasing the contact area and mechanical interlocking force between the adhesive and the current collector, and thus effectively improving the bonding effect when the current collector and the electrode are combined. Therefore, the technical solution of this application effectively solves the problem of low adhesion or material shedding that easily occurs when dry current collectors are combined with electrodes in related technologies.

[0026] Specifically, the rough, recessed structure is formed by laser etching. The width of the current collector is greater than or equal to 100 mm.

[0027] The thickness of the carbon coating structure 20 can be 1μm, 2μm, 3μm or other dimensions.

[0028] like Figures 1 to 3 As shown, in Embodiment 1, the rough recessed structure 30 includes a hole structure. The hole structure is relatively simple to process and can effectively increase the surface area of ​​the carbon coating layer structure 20, thereby increasing the contact area of ​​the adhesive.

[0029] Specifically, in Embodiment 1, the hole structure is a circular concave hole. Of course, the hole structure described above can also be an elliptical concave hole, a triangular concave hole, a rectangular concave hole, or other irregular concave holes.

[0030] like Figures 1 to 3 As shown, in Embodiment 1, the ratio of the sum of the projected areas of the plurality of rough recessed structures 30 on the metal layer structure 10 to the projected area of ​​the carbon coating structure 20 on the metal layer structure 10 is between 0.01 and 0.1. This ratio setting ensures reduced contact resistance of the current collector and guarantees adhesion.

[0031] Specifically, the ratio mentioned above can be 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or other values.

[0032] like Figures 1 to 3 As shown, in Embodiment 1, the rough recessed structure 30 includes a pore structure with a diameter between 5 μm and 15 μm, and the density of multiple pore structures is 500 pores / m². 2 Up to 1000 / m 2 The above settings ensure the uniformity of the pore structure and avoid performance differences caused by local over-density or over-sparseness.

[0033] Specifically, the diameter of the aforementioned pore structure can be 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, or other values. The pore density can be 510 pores / m². 2 520 pieces / m 2 530 pieces / m 2 540 units / m 2 550 pieces / m 2 560 units / m 2 570 units / m 2 580 units / m 2 590 units / m 2 600 pieces / m 2 610 units / m 2 620 pieces / m 2 630 pieces / m2 640 units / m 2 650 pieces / m 2 660 units / m 2 670 units / m 2 680 units / m 2 690 units / m 2 700 pieces / m 2 710 units / m 2 720 pieces / m 2 730 pieces / m 2 740 units / m 2 750 pieces / m 2 760 units / m 2 770 units / m 2 780 units / m 2 790 units / m 2 800 pieces / m 2 810 units / m 2 820 pieces / m 2 830 units / m 2 840 units / m 2 850 pieces / m 2 860 units / m 2 870 units / m 2 880 units / m 2 890 units / m 2 900 pieces / m 2 910 units / m 2 920 pieces / m 2 930 pieces / m 2 940 units / m 2 950 pieces / m 2 960 units / m 2 970 units / m 2 980 units / m 2 990 pieces / m 2 Or it could be any other value.

[0034] like Figures 1 to 3 As shown, in Embodiment 1, the distance between adjacent hole structures is between 15mm and 30mm. This arrangement allows for a more reasonable arrangement of the hole structures, thereby avoiding excessive density.

[0035] Specifically, the aforementioned distance can be 15.5mm, 16mm, 16.5mm, 17mm, 17.5mm, 18mm, 18.5mm, 19mm, 19.5mm, 20mm, 20.5mm, 21mm, 21.5mm, 22mm, 22.5mm, 23mm, 23.5mm, 24mm, 24.5mm, or other values.

[0036] like Figures 1 to 3 As shown, in Example 1, the depth 'a' of the rough recessed structure 30 and the thickness 'b' of the carbon coating layer structure 20 satisfy the following condition: 0.2b ≤ a ≤ 0.6b. This depth control is to maximize the adhesion between the current collector and the active material without penetrating the carbon coating layer structure 20.

[0037] Specifically, the depth a of the rough recessed structure 30 and the thickness b of the carbon coating structure 20 can be a = 0.25b, a = 0.3b, a = 0.35b, a = 0.4b, a = 0.45b, a = 0.5b, a = 0.55b, or other values.

[0038] like Figures 1 to 3 As shown, in Embodiment 1, the metal layer structure 10 is made of copper or aluminum. Copper or aluminum possesses excellent electrical conductivity and chemical stability, enabling it to effectively carry and transmit current while remaining stable in a battery environment.

[0039] Of course, the metal layer structure 10 can also be other conductive metals.

[0040] like Figures 1 to 3 As shown, in Example 1, the material of the carbon coating layer structure 20 is graphite or carbon. Graphite or carbon can provide additional conductivity and, at the same time, serve as a base for the binder, enhancing the bonding effect.

[0041] like Figures 1 to 3 As shown, in Embodiment 1, a plurality of rough recessed structures 30 are arranged in an array, and the distance between two adjacent rough recessed structures 30 gradually increases in the direction from the center of the carbon coating structure 20 to the edge of the carbon coating structure 20. The above arrangement can optimize the conductivity performance.

[0042] It should be noted that the difference between Embodiment 2 and Embodiment 1 is that the shape of the rough recessed structure 30 is different.

[0043] like Figures 4 to 6 As shown, in Embodiment 2, the rough recessed structure 30 is a strip-shaped groove structure. This design increases the contact area and mechanical interlocking force between the adhesive and the current collector.

[0044] It should be noted that the difference between Embodiment 3 and Embodiment 1 is that the shape of the rough recessed structure 30 is different.

[0045] like Figure 7 and Figure 8 As shown, in Embodiment 3, the rough recessed structure 30 is a sawtooth groove structure. This design increases the contact area and mechanical interlocking force between the adhesive and the current collector.

[0046] It should be noted that the difference between Embodiment 4 and Embodiment 1 is that the shape of the rough recessed structure 30 is different.

[0047] like Figure 9 and Figure 10 As shown, in Embodiment 4, the rough recessed structure 30 is a wavy groove structure. This design increases the contact area and mechanical interlocking force between the adhesive and the current collector.

[0048] In other embodiments, the rough recessed structure 30 may also be a striped scratch structure, a serrated scratch structure, a wavy scratch structure, or other shapes.

[0049] It should be noted that in Embodiments 2 to 4, the minimum distance between two adjacent rough recessed structures 30 is greater than the size of the tab blank area. Simultaneously, the extending direction of the rough recessed structure 30 is the same as the tape carrying direction.

[0050] According to another aspect of this application, a battery is provided. The battery of this embodiment includes a cell, the cell including a current collector and an active material layer coated on the surface of the current collector, the current collector being the aforementioned current collector.

[0051] The following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.

[0052] [Battery]

[0053] The battery in this application is a secondary battery, also known as a rechargeable battery or storage battery, which refers to a battery that can be used again after being discharged by recharging to activate the active materials.

[0054] Typically, a secondary battery consists of a battery cell, an electrolyte, and a casing. The battery cell includes a positive electrode, a negative electrode, and a separator. The battery cell and electrolyte are assembled inside the casing. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, located between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, situated between the positive and negative electrodes, mainly serves to conduct active ions.

[0055] As an example, the preparation process of a secondary battery is as follows: the positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, the electrodes are wound or stacked to obtain a cell. The cell is placed in a casing, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a secondary battery is obtained.

[0056] [Positive electrode tablets]

[0057] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector. The positive electrode film layer includes a positive electrode active material, which can be any existing publicly disclosed positive electrode active material or a positive electrode active material optimized based on existing materials.

[0058] This application does not impose any particular restrictions on the type of positive electrode active material for the positive electrode sheet. As an example, the positive electrode active materials in this application include lithium-containing transition metal oxides (e.g., LiCoO2), phosphides (e.g., LiFePO4), or lithium intercalation compounds (e.g., positive electrode materials for binary lithium batteries such as lithium cobalt oxide and lithium nickel oxide, or positive electrode materials for ternary lithium batteries such as lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide).

[0059] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, rolling, cutting and other processes.

[0060] In this application, the binder is used to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. This application does not impose any particular limitation on the type of binder for the positive electrode sheet; the binder can be any conventional choice in the battery industry. Specifically, the binder can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polyimide (PI), polyacrylic acid (PAA), polyacrylate, polyolefin, sodium carboxymethyl cellulose (CMC), or sodium alginate.

[0061] This application does not impose any particular restrictions on the positive electrode current collector, as long as it is conductive and will not cause adverse chemical changes in the battery, and can be made of, for example: stainless steel, aluminum, nickel, titanium, sintered carbon; or aluminum or stainless steel that has been surface treated with one of carbon, nickel, titanium, silver, etc.

[0062] [Negative electrode plate]

[0063] The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. The negative electrode active material layer comprises a silicon-based material. This application does not specifically limit the type of silicon-based material; the silicon-based material can be a silicon-carbon material and / or a silicon-oxygen material. As an example, the silicon-based material can be one or more of silicon-carbon composite negative electrode materials, silicon suboxide negative electrode materials, modified silicon suboxide negative electrode materials, and nano-silicon materials. The negative electrode active material in the negative electrode active material layer may also optionally include one or more of artificial graphite, natural graphite, and hard carbon.

[0064] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, rolling, cutting and other processes.

[0065] This application does not specifically limit the type of negative electrode conductive agent. In some embodiments, as an example, the negative electrode conductive agent can be one or more of conventional negative electrode conductive agents such as acetylene black and carbon nanotubes. This application does not specifically limit the type of negative electrode binder. In some embodiments, as an example, the binder can be one or more of conventional negative electrode binders such as styrene-butadiene rubber latex (SBR), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and sodium carboxymethyl cellulose (CMC). In this application, the binder is preferably PAA, SBR, and CMC, and the mass ratio of PAA, SBR, and CMC can be (34.38-74.29):(20-59.38):(5-7.14).

[0066] This application does not impose specific limitations on the type of negative electrode current collector. In some embodiments, as an example, the negative electrode current collector can be one of the conventional negative electrode current collectors such as copper foil.

[0067] Electrolyte

[0068] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. As an example, the electrolyte in this application can be any electrolyte suitable for electrochemical energy storage devices in the art. The electrolyte includes an electrolyte and a solvent; the electrolyte typically includes a lithium salt, and additives may also be added to the electrolyte.

[0069] Specifically, the lithium salt includes at least one selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be 0.5–5 mol / L.

[0070] Specifically, the solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0071] In some implementations, as an example, the additive may be a conventional electrolyte additive such as fluoroethylene carbonate (FEC), chloroethylene carbonate (CEC), or vinylene carbonate (VC).

[0072] [Septum]

[0073] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0074] In some embodiments, as an example, the diaphragm can be one of PP, PE, or PP / PF; the diaphragm can also be a structure in which a coating is formed on the surface of the base film, wherein the base film coating can be one of PP, PE, or PP / PF, and the coating can be an inorganic coating and / or an organic coating. The inorganic coating can be selected from alumina ceramic layers, osmium silicate, etc., and the organic coating can be selected from PVDF, etc.

[0075] In the description of this utility model, it should be understood that "multiple" means a quantity of two or more. Directional terms such as "front, back, up, down, left, right," "horizontal, vertical, perpendicular, horizontal," and "top, bottom" indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0076] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0077] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0078] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A current collector, characterized in that, include: Metal layer structure (10); A carbon coating layer structure (20) is disposed on the metal layer structure (10); Multiple rough recessed structures (30) are spaced apart on the carbon coating structure (20), and the maximum depth of each rough recessed structure (30) is less than the thickness of the carbon coating structure (20).

2. The current collector according to claim 1, characterized in that, The rough recessed structure (30) includes a hole structure, a groove structure, or a scratch structure.

3. The current collector according to claim 1, characterized in that, The ratio of the sum of the projected areas of the plurality of rough recessed structures (30) on the metal layer structure (10) to the projected area of ​​the carbon coating structure (20) on the metal layer structure (10) is between 0.01 and 0.

1.

4. The current collector according to claim 1, characterized in that, The rough recessed structure (30) includes a pore structure with a diameter between 5 μm and 15 μm, and the density of multiple pore structures is 500 per m. 2 Up to 1000 / m 2 between.

5. The current collector according to claim 4, characterized in that, The distance between adjacent hole structures is between 15 mm and 30 mm.

6. The current collector according to claim 1, characterized in that, The depth a of the rough recessed structure (30) and the thickness b of the carbon coating layer structure (20) satisfy the following condition: 0.2b≤a≤0.6b.

7. The current collector according to claim 1, characterized in that, The metal layer structure (10) is made of copper or aluminum.

8. The current collector according to claim 1, characterized in that, The material of the carbon coating layer structure (20) is graphite or carbon.

9. The current collector according to claim 1, characterized in that, Multiple rough recessed structures (30) are arranged in an array, and the distance between two adjacent rough recessed structures (30) gradually increases in the direction from the center of the carbon coating structure (20) to the edge of the carbon coating structure (20).

10. A battery, comprising a cell, characterized in that, The battery cell includes a current collector and an active material layer coated on the surface of the current collector, wherein the current collector is the current collector according to any one of claims 1 to 9.

Images