Sodium ion battery

Abstract

The utility model discloses a sodium ion battery which comprises a positive plate and a negative plate, the positive plate and the negative plate are isolated from each other through a diaphragm, the positive plate comprises a positive current collector and a positive material layer coated on the positive current collector, and the negative plate comprises a negative current collector and a negative material layer coated on the negative current collector. Each of the positive current collector and the negative current collector comprises an aluminum foil base material and a copper-aluminum alloy powder coating thermally sprayed on the surface of the aluminum foil base material. The sodium ion battery disclosed by the utility model has the characteristics of excellent conductivity, strong adhesive force, high stability and good processability.

Description

Technical Field

[0001] The utility model relates to the technical field of sodium ion batteries, in particular to a sodium ion battery. Background Art

[0002] With the development of the new energy industry, lithium-ion batteries have become increasingly vulnerable to cost fluctuations due to the high volatility of lithium ore prices. In contrast, sodium-ion batteries are gaining attention for their safety, long lifespan, and low cost.

[0003] Based on cost considerations, the current collector of sodium ion batteries tends to use aluminum foil as the current collector material, but the conductivity of aluminum foil current collector is poor, which directly restricts the promotion and application of sodium ion batteries.

[0004] In response to this, Chinese utility model patent CN210224170U discloses a sodium ion battery, including a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer coated on at least one surface of the positive electrode collector. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer coated on at least one surface of the negative electrode collector. It is characterized in that: the positive electrode collector and the negative electrode collector both include a foil layer and a carbon coating layer coated on both surfaces of the foil layer.

[0005] By setting and coating a carbon layer, the utility model reduces the proportion of adhesives and conductive agents and improves the energy density of the battery on the one hand, and improves the adhesion between the active material layer and the current collector and reduces the problem of positive and negative electrode material falling off on the other hand.

[0006] However, carbon-coated carbon materials still have the following problems:

[0007] For example, on the conductive side, the presence of a carbon coating may reduce the overall conductivity. Carbon-coated materials are generally less conductive than aluminum metal, which may lead to a decrease in battery performance during high-rate discharge.

[0008] For example, in terms of mechanical strength, the mechanical strength of carbon-coated aluminum foil may not be as good as that of pure aluminum foil. Especially in high temperature or high pressure environments, the coating may peel off or deform, thereby affecting the overall structure and stability of the battery.

[0009] For example, in terms of chemical stability, the carbon-coated material may react with the electrolyte during battery operation, causing degradation or failure of the coating. This chemical reaction may affect the cycle life and safety of the battery.

[0010] For example, in terms of cost, the production process of carbon-coated aluminum foil is relatively complex, which may increase the cost of materials. In large-scale production, this cost increase may affect the economic feasibility of sodium-ion batteries.

[0011] Based on this consideration, the technical solution prefers conductive carbon materials such as nano-conductive graphite, carbon-coated particles, and carbon nanotubes in the selection of carbon coating layer. However, the high cost, great processing difficulty, and poor coating uniformity have seriously restricted the improvement of sodium ion battery performance. Utility Model Content

[0012] The purpose of the utility model is to provide a sodium ion battery with the characteristics of excellent conductivity, strong adhesion, high stability and good processability.

[0013] The utility model can be realized by the following technical solutions:

[0014] The utility model discloses a sodium ion battery, comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet and the negative electrode sheet are isolated from each other by a diaphragm, the positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer coated on the positive electrode current collector, the negative electrode sheet comprises a negative electrode current collector and a negative electrode material layer coated on the negative electrode current collector, and the positive electrode current collector and the negative electrode current collector both comprise an aluminum foil substrate and a copper-aluminum alloy powder coating thermally sprayed on the surface of the aluminum foil substrate.

[0015] Furthermore, the copper-aluminum alloy in the copper-aluminum alloy powder is of the grade ZAICu10 or ZAlCu4, both of which are conventional copper-aluminum alloys with excellent performance, wide sources and low cost.

[0016] Furthermore, the copper-aluminum alloy powder coating is extruded to form regular or irregular patterns during the thermal spraying process, effectively increasing the bonding ability between the copper-aluminum alloy powder coating and the positive electrode material layer or the negative electrode material layer.

[0017] Furthermore, the regular patterns are staggered diagonal lines, and adjacent diagonal lines are in opposite directions, forming bonding contact surfaces at different angles, thereby improving the bonding ability.

[0018] Furthermore, the regular pattern is a grid pattern, and the grid pattern is a square grid or a diamond grid, forming a concave-convex bonding contact surface to improve the bonding ability.

[0019] Furthermore, an anisotropic conductive adhesive layer is provided between the alloy powder coating and the positive electrode material layer or the negative electrode material layer, which not only ensures adhesion but also improves conductivity.

[0020] Furthermore, the positive electrode material layer is a polyanion material layer, a Prussian basket material layer or a layered oxide material layer, which meets the use requirements of different types of sodium ion batteries.

[0021] Furthermore, the polyanion material layer is a sodium iron sulfate material layer or a composite sodium iron phosphate material layer, which meets the use requirements of different polyanion materials.

[0022] Furthermore, the aluminum foil substrate is a single-sided wool aluminum foil or a double-sided wool aluminum foil, both of which are conventional aluminum foils with low cost.

[0023] The utility model provides a sodium ion battery, which has the following beneficial effects:

[0024] First, it has excellent electrical conductivity. Copper-aluminum alloy is used as the coating. Based on the alloy effect, the conductivity of copper-aluminum alloy is usually between pure copper and pure aluminum. Compared with simple aluminum foil or carbon-coated materials, it has stronger electrical conductivity.

[0025] Second, strong adhesion. During the thermal spraying process, the molten alloy powder is sprayed onto the substrate surface at high temperature, forming a good mechanical bond and enhancing the adhesion of the coating. Moreover, during the spraying process, the impact of the powder can roughen the substrate surface, further improving the adhesion of the coating.

[0026] Third, high stability. Thermal spraying can significantly improve the wear resistance of copper-aluminum alloys. At the same time, thermal spraying can form a protective layer on the surface of the substrate, enhancing its corrosion resistance and extending its service life. In addition, during the thermal spraying process, the heat-affected zone of the substrate is small, reducing the risk of deformation or performance degradation caused by high temperature. At the same time, since the temperature of thermal spraying is relatively low, the original characteristics of the substrate can be maintained, avoiding the negative effects of heat treatment.

[0027] Fourth, the processability is good. Thermal spraying technology allows the thickness of the coating to be adjusted as needed to adapt to different application requirements. At the same time, multi-layer coatings can be formed through multiple spraying to achieve more complex performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Attachment Figure 1 This is a schematic structural diagram of a sodium ion battery of the present invention;

[0029] The symbols in the accompanying drawings include: 100, positive electrode sheet; 110, positive electrode current collector; 111, aluminum foil substrate; 112, copper-aluminum alloy powder coating; 200, separator; 300, negative electrode sheet; 310, negative electrode current collector; 311, aluminum foil substrate; 312, copper-aluminum alloy powder coating. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in further detail below in conjunction with embodiments.

[0031] like Figure 1As shown, taking a laminated battery as an example, the present invention discloses a sodium ion battery, comprising a positive electrode sheet 100 and a negative electrode sheet 300, the positive electrode sheet 100 and the negative electrode sheet 300 being separated from each other by a separator 200, the positive electrode sheet 100 comprising a positive electrode current collector 110 and a positive electrode material layer 120 coated on the positive electrode current collector 110, the negative electrode sheet 300 comprising a negative electrode current collector 310 and a negative electrode material layer 320 coated on the negative electrode current collector 310, the positive electrode current collector 110 and the negative electrode current collector 310 both comprising an aluminum foil substrate 111 and a copper-aluminum alloy powder coating 112, 312 thermally sprayed on the surface of the aluminum foil substrate 111, 311. Similarly, although not specifically illustrated, the positive and negative electrode sheets of a cylindrical wound battery also employ similar structures, differing from the prior art in the copper-aluminum alloy powder coating of the current collector.

[0032] In this invention, based on cost and performance considerations, the grade of the copper-aluminum alloy in the copper-aluminum alloy powder is ZAICu10 or ZAlCu4; the aluminum foil substrate is single-sided wool aluminum foil or double-sided wool aluminum foil.

[0033] In the present invention, to enhance bonding, a copper-aluminum alloy powder coating is extruded during the thermal spraying process to form a regular or irregular pattern. Specifically, the regular pattern is a staggered pattern, with adjacent staggered patterns running in opposite directions. Alternatively, the regular pattern can be a grid pattern, with the grid pattern being a square or diamond-shaped grid.

[0034] In the present invention, based on the consideration of electrical conductivity and bonding ability, an anisotropic conductive adhesive layer is provided between the alloy powder coating layer and the positive electrode material layer or the negative electrode material layer.

[0035] The present invention meets the application requirements of different sodium ion batteries. The positive electrode material layer is a polyanion material layer, a Prussian basket material layer, or a layered oxide material layer. Specifically, the polyanion material layer is a sodium iron sulfate material layer or a composite sodium iron phosphate material layer.

[0036] In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do 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 invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0038] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0039] The above embodiments are merely specific embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art will be able to make various modifications and improvements without departing from the scope of the present invention, and these obvious alternatives are all within the scope of protection of the present invention.

Claims

1. A sodium ion battery comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet and the negative electrode sheet are separated from each other by a separator, characterized in that: The positive electrode sheet includes a positive electrode collector and a positive electrode material layer coated on the positive electrode collector, and the negative electrode sheet includes a negative electrode collector and a negative electrode material layer coated on the negative electrode collector. The positive electrode collector and the negative electrode collector both include an aluminum foil substrate and a copper-aluminum alloy powder coating thermally sprayed on the surface of the aluminum foil substrate.

2. The sodium ion battery according to claim 1, wherein: The grade of the copper-aluminum alloy in the copper-aluminum alloy powder is ZAICu10 or ZAlCu4.

3. The sodium ion battery according to claim 2, wherein: The copper-aluminum alloy powder coating is extruded to form regular or irregular lines during the thermal spraying process.

4. The sodium ion battery according to claim 3, wherein: The regular pattern is twill lines that alternate in different directions, with adjacent twill lines in opposite directions.

5. The sodium ion battery according to claim 3, wherein: The regular patterns are grid patterns, and the grid patterns are square grids or diamond grids.

6. The sodium ion battery according to claim 4 or 5, characterized in that: An anisotropic conductive adhesive layer is provided between the alloy powder coating and the positive electrode material layer or the negative electrode material layer.

7. The sodium ion battery according to claim 6, characterized in that: The positive electrode material layer is a polyanion material layer, a Prussian basket material layer or a layered oxide material layer.

8. The sodium ion battery according to claim 7, characterized in that: The polyanionic material layer is a sodium iron sulfate material layer or a composite sodium iron phosphate material layer.

9. The sodium ion battery according to claim 8, characterized in that: The aluminum foil substrate is a single-sided wool aluminum foil or a double-sided wool aluminum foil.

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