Negative pole piece structure and sodium ion battery

Abstract

The utility model provides a negative pole piece structure and a sodium ion battery. The negative pole piece structure comprises a current collecting piece body and a coating assembly, wherein the coating assembly is coated and formed on the outer surface of the current collecting piece body; the current collecting sheet body comprises a first thick edge part, a flat and thin part and a second thick edge part which are connected in sequence, and the flat and thin part is located between the first thick edge part and the second thick edge part; a first etching rolling area is formed on the surface, corresponding to the first thick edge part, of the coating assembly; a second etching rolling area is formed on the surface, corresponding to the second thick edge part, of the coating assembly; the surface of the coating assembly corresponding to the flat and thin part extends to the first etching rolling area and the second etching rolling area respectively. The negative pole piece structure is relatively good in overall flatness.

Description

Technical Field

[0001] This disclosure relates to the technical field of sodium-ion batteries, and in particular to a negative electrode structure and a sodium-ion battery. Background Technology

[0002] Sodium-ion batteries are rechargeable batteries that rely on the movement of sodium ions between the positive and negative electrodes to complete charging and discharging. Sodium-ion batteries are widely used in new energy vehicles, electric bicycles, aerospace, electronic products, energy storage devices, and drones. A sodium-ion battery consists of a positive electrode, a separator, a negative electrode, and a casing. The separator is positioned between the positive and negative electrodes. The positive electrode, separator, and negative electrode are wound together to form a cell, which is then assembled inside the casing.

[0003] The negative electrode of the related technology includes a current collector body, a first coating layer and a second coating layer. The first coating layer is coated on the outer surface of the current collector body, and the second coating layer is coated on the outer surface of the first coating layer, such as Chinese Patent No. CN202311578696.1.

[0004] However, since the second coating layer is coated on the outer surface of the first coating layer, and the first coating layer is coated on the outer surface of the current collector, the coating process of the negative electrode sheet is completed. After the coating process, the negative electrode sheet needs to be dried. When the negative electrode sheet is dried, thick edges will form on both sides of the negative electrode sheet, resulting in the problem that the negative electrode sheet is thin in the middle and thick at both sides, which makes the overall flatness of the negative electrode sheet poor. Utility Model Content

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a negative electrode structure and sodium-ion battery with better overall flatness.

[0006] The purpose of this disclosure is achieved through the following technical solution:

[0007] A negative electrode structure includes a current collector body and a coating assembly, wherein the coating assembly coats and forms a coating on the outer surface of the current collector body; the current collector body includes a first thick edge portion, a thin flat portion and a second thick edge portion connected in sequence, wherein the thin flat portion is located between the first thick edge portion and the second thick edge portion;

[0008] A first etched roll pressing area is formed on the surface of the coating component corresponding to the first thick edge portion;

[0009] A second etch roll pressing area is formed on the surface of the coating assembly corresponding to the second thick edge portion;

[0010] The surfaces of the coating components corresponding to the flat, thin portion extend to the first etching roll pressing area and the second etching roll pressing area, respectively.

[0011] In one embodiment, the flow collector is a one-piece molded structure.

[0012] In one embodiment, the coating component is a hard carbon coating composite structure.

[0013] In one embodiment, the current collector is an aluminum foil sheet structure.

[0014] In one embodiment, the coating assembly includes a first coating layer and a second coating layer, the first coating layer being coated and formed on the outer surface of one side of the current collector, and the second coating layer being coated and formed on the outer surface of the other side of the current collector.

[0015] In one embodiment, the first coating layer and the second coating layer are axially symmetrical about the central axis of the current collector.

[0016] In one embodiment, both the first coating layer and the second coating layer are hard carbon coating composite layers.

[0017] In one embodiment, the first thick edge portion and the second thick edge portion are symmetrically distributed about the central axis of the flat thin portion.

[0018] A sodium-ion battery comprising the negative electrode structure described in any of the above embodiments.

[0019] Compared with the prior art, this disclosure has at least the following advantages:

[0020] 1. The surface of the coating component corresponding to the first thick edge is immersed in the etching solution to form a first etching zone, so that the thickness of the surface of the coating component corresponding to the first thick edge is reduced under the etching action of the etching solution to form a first etching zone; then, the first etching zone is connected to the rolling end of the rolling device to form a first etching rolling zone, so that the rolling end of the rolling device compacts the outer surface of the first etching zone to form a first etching rolling zone; the surface of the coating component corresponding to the second thick edge is immersed in the etching solution to form a second etching zone, so that the thickness of the surface of the coating component corresponding to the second thick edge is reduced under the etching action of the etching solution to form a second etching zone; then, the second etching zone is connected to the rolling end of the rolling device to form a second etching rolling zone, so that the rolling end of the rolling device compacts the outer surface of the second etching zone to form a second etching rolling zone, so that the thickness of both sides of the negative electrode structure is reduced under the combined action of etching and rolling.

[0021] 2. Since the coating component is coated and formed on the outer surface of the current collector, the coating process of the negative electrode structure is completed. After the coating process, the negative electrode structure needs to be dried. During the drying process, thick edges will be formed on both sides of the negative electrode structure. That is, the two sides of the negative electrode structure will form a first thick edge and a second thick edge, respectively. The thickness of the two sides of the negative electrode structure is reduced under the combined action of etching and rolling. At this time, the two sides of the negative electrode structure will form a first etching and rolling area and a second etching and rolling area, respectively. The surface of the coating component corresponding to the thin part extends to the first etching and rolling area and the second etching and rolling area, so that the end face of the thin part is flush with the end face of the first etching and rolling area and the end face of the second etching and rolling area, respectively. This avoids the problem of the negative electrode being thin in the middle and thick at both sides in the prior art, so that the overall thickness of the negative electrode structure tends to be consistent, and the overall flatness of the negative electrode structure is better. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the negative electrode structure of one embodiment;

[0024] Figure 2 for Figure 1 A schematic diagram of the negative electrode structure under processing from another perspective;

[0025] Figure 3 for Figure 2 A schematic diagram of the negative electrode structure after etching.

[0026] Figure 4 for Figure 3 The diagram shows the structure of the etched negative electrode sheet after roll forming. Detailed Implementation

[0027] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0028] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] This disclosure provides a negative electrode structure, including a current collector body and a coating assembly, wherein the coating assembly is coated and formed on the outer surface of the current collector body.

[0031] Furthermore, the current collector includes a first thick edge portion, a flat thin portion, and a second thick edge portion connected in sequence, with the flat thin portion located between the first thick edge portion and the second thick edge portion; a first etching roll pressing area is formed on the surface of the coating component corresponding to the first thick edge portion; a second etching roll pressing area is formed on the surface of the coating component corresponding to the second thick edge portion; and the surface of the coating component corresponding to the flat thin portion extends to the first etching roll pressing area and the second etching roll pressing area, respectively.

[0032] In the aforementioned negative electrode structure, the surface of the coating component corresponding to the first thick edge is immersed in the etching solution to form a first etching zone, thereby reducing the thickness of the coating component surface under the etching action of the etching solution to form the first etching zone. Next, the first etching zone is connected to the rolling end of the rolling device to form a first etching rolling zone, thereby pressing the outer surface of the first etching zone with the rolling end of the rolling device to form the first etching rolling zone. Similarly, the surface of the coating component corresponding to the second thick edge is immersed in the etching solution to form a second etching zone, thereby reducing the thickness of the coating component surface under the etching action of the etching solution to form the second etching zone. Next, the second etching zone is connected to the rolling end of the rolling device to form a second etching rolling zone, thereby pressing the outer surface of the second etching zone with the rolling end of the rolling device to form the second etching rolling zone. This results in the thickness of both edges of the negative electrode structure being reduced under the combined action of etching and rolling.

[0033] Since the coating component is coated and formed on the outer surface of the current collector, the coating process of the negative electrode structure is completed. After the coating process, the negative electrode structure needs to be dried. During the drying process, thick edges will form on both sides of the negative electrode structure. That is, the two sides of the negative electrode structure will form a first thick edge and a second thick edge, respectively. The thickness of the two sides of the negative electrode structure is reduced under the combined action of etching and rolling. At this time, the two sides of the negative electrode structure will form a first etching and rolling area and a second etching and rolling area, respectively. The surface of the coating component corresponding to the thin part extends to the first etching and rolling area and the second etching and rolling area, so that the end face of the thin part is flush with the end face of the first etching and rolling area and the end face of the second etching and rolling area, respectively. This avoids the problem of the negative electrode being thin in the middle and thick at both sides in the prior art, so that the overall thickness of the negative electrode structure tends to be consistent, and the overall flatness of the negative electrode structure is better.

[0034] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0035] like Figures 1 to 4 As shown, a negative electrode structure 10 in one embodiment includes a current collector 100 and a coating component 200, wherein the coating component 200 is coated and formed on the outer surface of the current collector 100.

[0036] Furthermore, the current collector 100 includes a first thick edge portion 300, a thin flat portion 400, and a second thick edge portion 500 connected in sequence, with the thin flat portion 400 located between the first thick edge portion 300 and the second thick edge portion 500; a first etching roll pressing area 800 is formed on the surface of the coating component 200 corresponding to the first thick edge portion 300; a second etching roll pressing area 900 is formed on the surface of the coating component 200 corresponding to the second thick edge portion 500; and the surface of the coating component 200 corresponding to the thin flat portion 400 extends to the first etching roll pressing area 800 and the second etching roll pressing area 900, respectively.

[0037] In this embodiment, a first etching roll pressing region 800 is formed on the surface of the coating component 200 corresponding to the first thick edge portion 300; that is, the surface of the coating component 200 corresponding to the first thick edge portion 300 is immersed in the etching solution to form a first etching region 600, so that the thickness of the surface of the coating component 200 corresponding to the first thick edge portion 300 is reduced under the etching action of the etching solution to form the first etching region 600; then, the first etching region 600 is connected to the roll pressing end of the roll pressing device to form the first etching roll pressing region 800, so that the roll pressing end of the roll pressing device compacts the outer surface of the first etching region 600 to form the first etching roll pressing region 800.

[0038] Similarly, a second etching roll pressing region 900 is formed on the surface of the coating component 200 corresponding to the second thick edge portion 500; that is, the surface of the coating component 200 corresponding to the second thick edge portion 500 is immersed in the etching solution to form a second etching region 700, so that the thickness of the surface of the coating component 200 corresponding to the second thick edge portion 500 is reduced under the etching action of the etching solution to form the second etching region 700; then, the second etching region 700 is connected to the roll pressing end of the roll pressing device to form a second etching roll pressing region 900, so that the roll pressing end of the roll pressing device compacts the outer surface of the second etching region 700 to form the second etching roll pressing region 900. The etching solution is a potassium hydroxide solution. The cross-sections of both the first etching region 600 and the second etching region 700 are serrated.

[0039] It should be noted that the working principle of using etching solution to etch the surface of coated component 200 is existing technology.

[0040] The aforementioned negative electrode structure 10, since the surface of the coating component 200 corresponding to the first thick edge portion 300 is immersed in the etching solution to form a first etching region 600, the thickness of the surface of the coating component 200 corresponding to the first thick edge portion 300 is reduced under the etching action of the etching solution to form the first etching region 600; then, the first etching region 600 is connected to the rolling end of the rolling device to form a first etching rolling region 800, so that the rolling end of the rolling device compacts the outer surface of the first etching region 600 to form the first etching rolling region 800; the second thick edge portion 500 corresponds to The surface of the coating component 200 is immersed in the etching solution to form a second etching region 700, so that the thickness of the surface of the coating component 200 corresponding to the second thick edge 500 is reduced under the etching action of the etching solution to form the second etching region 700; then, the second etching region 700 is connected to the rolling end of the rolling device to form a second etching rolling region 900, so that the rolling end of the rolling device presses the outer surface of the second etching region 700 to form the second etching rolling region 900, so that the thickness of both sides of the negative electrode structure 10 is reduced under the combined action of etching and rolling.

[0041] Since the coating component 200 is coated and formed on the outer surface of the current collector 100, the coating process of the negative electrode structure 10 is completed. After the coating process, the negative electrode structure 10 needs to be dried. During the drying process, thick edges will form on both sides of the negative electrode structure 10, that is, a first thick edge portion 300 and a second thick edge portion 500 are formed on both sides of the negative electrode structure 10, respectively. The thickness of the two sides of the negative electrode structure 10 is reduced under the combined action of etching and rolling. At this time, the thickness of the two sides of the negative electrode structure 10 is reduced. The first etching roll pressing area 800 and the second etching roll pressing area 900 are respectively formed on the edge. The surface of the coating component 200 corresponding to the flat thin portion 400 extends to the first etching roll pressing area 800 and the second etching roll pressing area 900 respectively, so that the end face of the flat thin portion 400 is flush with the end face of the first etching roll pressing area 800 and the end face of the second etching roll pressing area 900 respectively. This avoids the problem of the negative electrode sheet being thin in the middle and thick at both sides in the prior art, so that the overall thickness of the negative electrode sheet structure 10 tends to be consistent, and the overall flatness of the negative electrode sheet structure 10 is better.

[0042] In one embodiment, the current collector 100 is a one-piece molded structure to make the current collector 100 have high structural strength.

[0043] In one embodiment, the coating component 200 is a hard carbon coating composite structure, so that the coating component 200 can accommodate more sodium ions, thereby improving the sodium intercalation capability of the negative electrode structure 10.

[0044] In one embodiment, the current collector 100 is an aluminum foil sheet structure, which reduces the manufacturing cost of the negative electrode structure 10.

[0045] like Figures 1 to 4 As shown, in one embodiment, the coating assembly 200 includes a first coating layer 210 and a second coating layer 220. The first coating layer 210 is coated and formed on the outer surface of one side of the current collector 100, and the second coating layer 220 is coated and formed on the outer surface of the other side of the current collector 100, so that the sodium intercalation capability of the negative electrode structure 10 is better.

[0046] like Figures 1 to 4 As shown, in one embodiment, the first coating layer 210 and the second coating layer 220 are symmetrically distributed about the central axis of the current collector 100, which makes the negative electrode structure 10 more aesthetically pleasing.

[0047] In one embodiment, both the first coating layer 210 and the second coating layer 220 are hard carbon coating composite layers, which makes the sodium intercalation capability of the negative electrode structure 10 better.

[0048] like Figures 2 to 4As shown, in one embodiment, the first thick edge portion 300 and the second thick edge portion 500 are symmetrically distributed about the central axis of the thin flat portion 400, which makes the structure of the negative electrode sheet 10 more aesthetically pleasing.

[0049] This disclosure also provides a sodium-ion battery, including the negative electrode structure 10 of any of the above embodiments.

[0050] Compared with the prior art, this disclosure has at least the following advantages:

[0051] 1. Since the surface of the coating component 200 corresponding to the first thick edge portion 300 is immersed in the etching solution to form a first etching region 600, the thickness of the surface of the coating component 200 corresponding to the first thick edge portion 300 is reduced under the etching action of the etching solution to form the first etching region 600; then, the first etching region 600 is connected to the rolling end of the rolling device to form a first etching rolling region 800, so that the rolling end of the rolling device presses the outer surface of the first etching region 600 to form the first etching rolling region 800; the coating component corresponding to the second thick edge portion 500 The surface of the coating component 200 is immersed in the etching solution to form a second etching region 700, so that the thickness of the surface of the coating component 200 corresponding to the second thick edge 500 is reduced under the etching action of the etching solution to form the second etching region 700; then, the second etching region 700 is connected to the rolling end of the rolling device to form a second etching rolling region 900, so that the rolling end of the rolling device presses the outer surface of the second etching region 700 to form the second etching rolling region 900, so that the thickness of both sides of the negative electrode structure 10 is reduced under the combined action of etching and rolling.

[0052] 2. Since the coating component 200 is coated and formed on the outer surface of the current collector 100, the coating process of the negative electrode structure 10 is completed. After the coating process, the negative electrode structure 10 needs to be dried. During the drying process, thick edges will form on both sides of the negative electrode structure 10, that is, a first thick edge portion 300 and a second thick edge portion 500 are formed on both sides of the negative electrode structure 10, respectively. The thickness of the two sides of the negative electrode structure 10 is reduced under the combined action of etching and rolling. At this time, the two sides of the negative electrode structure 10 The edges are respectively formed with a first etching roll pressing area 800 and a second etching roll pressing area 900. The surface of the coating component 200 corresponding to the flat thin portion 400 extends to the first etching roll pressing area 800 and the second etching roll pressing area 900, so that the end face of the flat thin portion 400 is flush with the end face of the first etching roll pressing area 800 and the end face of the second etching roll pressing area 900, thereby avoiding the problem of the negative electrode sheet being thin in the middle and thick at both sides in the prior art, so that the overall thickness of the negative electrode sheet structure 10 tends to be consistent, and the overall flatness of the negative electrode sheet structure 10 is better.

[0053] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A negative electrode structure, characterized in that, The device includes a current collector sheet and a coating assembly, wherein the coating assembly coats and forms a coating on the outer surface of the current collector sheet; the current collector sheet includes a first thick edge portion, a thin flat portion and a second thick edge portion connected in sequence, wherein the thin flat portion is located between the first thick edge portion and the second thick edge portion; A first etched roll pressing area is formed on the surface of the coating component corresponding to the first thick edge portion; A second etch roll pressing area is formed on the surface of the coating assembly corresponding to the second thick edge portion; The surfaces of the coating components corresponding to the flat, thin portion extend to the first etching roll pressing area and the second etching roll pressing area, respectively.

2. The negative electrode structure according to claim 1, characterized in that, The current collector plate is a one-piece molded structure.

3. The negative electrode structure according to claim 1, characterized in that, The coating component is a hard carbon coating composite structure.

4. The negative electrode structure according to claim 1, characterized in that, The current collector is an aluminum foil sheet structure.

5. The negative electrode structure according to claim 1, characterized in that, The coating assembly includes a first coating layer and a second coating layer. The first coating layer is coated and formed on the outer surface of one side of the current collector, and the second coating layer is coated and formed on the outer surface of the other side of the current collector.

6. The negative electrode structure according to claim 5, characterized in that, The first coating layer and the second coating layer are symmetrically distributed about the central axis of the current collector plate.

7. The negative electrode structure according to claim 5, characterized in that, Both the first coating layer and the second coating layer are hard carbon coating composite layers.

8. The negative electrode structure according to claim 1, characterized in that, The first thick edge portion and the second thick edge portion are symmetrically distributed about the central axis of the flat thin portion.

9. A sodium-ion battery, characterized in that, The negative electrode structure includes any one of claims 1 to 8.

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