Coating structure of sodium ion battery cell and secondary battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a coating structure of a sodium ion battery cell, which comprises a supporting part and coating parts arranged on two opposite sides of the supporting part, a coating space is formed between the two opposite coating parts, the supporting part is provided with a plurality of through holes which are correspondingly communicated with the coating space and are arranged at intervals, and the coating part is provided with a plurality of through holes which are communicated with the coating space. Each coating part is provided with a grid area and a hot melting area which are connected, the grid area is located between the supporting part and the hot melting area, and the grid area is provided with a plurality of hollowed-out grids arranged in sequence. According to the utility model, the absorption of the sodium ion naked battery cell to the electrolyte can be effectively increased, and the effective discharge of gas in the formation process can be ensured. In addition, the utility model also discloses a secondary battery.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and in particular relates to a coating structure of a sodium ion battery cell and a secondary battery. Background Art

[0002] Sodium-ion batteries have the advantages of being clean, efficient, economical, safe, and environmentally friendly, and are one of the important types of energy storage batteries. Among them, the radius of sodium ions is relatively large, about 1.34 times the radius of lithium ions, which makes the insertion and extraction of sodium ions easily hindered, and easily destroys the formed SEI film, resulting in gas production during the formation process, which in turn affects the performance and appearance of sodium-ion batteries. In the battery formation process, existing sodium-ion batteries have serious gas production, which can cause serious deformation of the battery in severe cases. For this reason, it is very necessary to develop a new cell coating structure to increase the absorption of electrolyte by sodium-ion bare cells and ensure the effective discharge of gas during the formation process. Utility Model Content

[0003] One of the purposes of the utility model is to provide a coating structure for a sodium ion battery cell in view of the deficiencies in the prior art, which can ensure efficient flow of electrolyte and gas between the inside and outside of the coating structure.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A coating structure for a sodium ion battery cell comprises a supporting portion and coating portions arranged on opposite sides of the supporting portion, a coating space is formed between the two opposite coating portions, the supporting portion is provided with a plurality of spaced through holes corresponding to and connected to the coating space, each of the coating portions respectively comprises a hot melt zone and a grid zone connected thereto, the grid zone is located between the supporting portion and the hot melt zone, wherein the grid zone comprises a plurality of hollow grids arranged in sequence.

[0006] As an improvement of the covering structure of the utility model, at least one of the covering parts has an auxiliary support area, the grid area is connected to the supporting part through the auxiliary support area, and the auxiliary support area is used to improve the supporting strength of the covering structure.

[0007] As an improvement of the coating structure of the utility model, the hollow area of ​​each grid is 0.02mm 2 ~10mm 2 .

[0008] As an improvement of the covering structure of the utility model, the grid area has one or more grids selected from the group consisting of ellipse, circle, triangle, sector, square, rhombus, trapezoid and regular hexagon.

[0009] As an improvement of the coating structure described in the utility model, the lengths of the hot melt zone and the grid zone are equal, the width of the hot melt zone is W1, and the width of the grid zone is W2, satisfying the relationship: 0.025≤W1 / W2≤0.2.

[0010] As an improvement of the covering structure of the present invention, the lengths of the auxiliary support area and the grid area are equal, the width of the auxiliary support area is W3, and the width of the grid area is W2, satisfying the relationship: 0.1≤W3 / W2≤0.35.

[0011] As an improvement of the covering structure of the utility model, the area of ​​the through hole is at least 1.05 to 40 times the hollow area of ​​the grid.

[0012] As an improvement of the covering structure of the present invention, the thickness of the supporting portion is not less than the thickness of the covering portion, and a plurality of the supporting portions are arranged at intervals between two opposite covering portions.

[0013] As an improvement of the covering structure of the utility model, the hot-melt areas of two opposite covering parts are connected correspondingly, and the grid areas of two opposite covering parts are connected correspondingly.

[0014] As an improvement of the coating structure described in the utility model, the hot-melt areas of two adjacent coating parts are connected correspondingly, and the grid areas of two adjacent coating parts are connected correspondingly.

[0015] As an improvement of the coating structure of the utility model, the grid area includes a first grid unit and a second grid unit connected to each other, a plurality of alternately distributed grid lines of the first grid unit are arranged obliquely or vertically along the edge of the first grid unit, and a plurality of alternately distributed grid lines of the second grid unit are arranged obliquely or vertically along the edge of the second grid unit.

[0016] As an improvement of the covering structure of the present invention, the grid area includes a plurality of grid units arranged in an array.

[0017] The second object of the utility model is to provide a secondary battery, comprising a battery cell and the above-mentioned covering structure, wherein a covering space is formed between two opposite covering parts of the covering structure, and the battery cell is arranged in the covering space, wherein the bottom of the battery cell is arranged on the supporting part of the covering structure.

[0018] The beneficial effect of the utility model is that the coating structure of the utility model includes a supporting part and a coating part arranged on opposite sides of the supporting part, a coating space for accommodating a battery cell is formed between the two opposite coating parts, the supporting part is provided with a plurality of spaced-apart through holes corresponding to and connected with the coating space, the through holes are used to allow the electrolyte to penetrate into the coating space, each coating part respectively has a connected grid area and a hot-melt area, the grid area is located between the supporting part and the hot-melt area, the grid area is connected to the supporting part, wherein the grid area has a plurality of hollow grids arranged in sequence, the exhaust of the battery cell and the infiltration of the electrolyte are efficiently realized through the plurality of hollow grids, and the service life and operation safety of the battery can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an expanded structural diagram of the coating structure of Example 1 of the utility model.

[0020] Figure 2 It is a three-dimensional structural diagram of the coating structure of Example 1 of the utility model.

[0021] Figure 3 This is an expanded structural diagram of the coating structure of Example 2 of the utility model.

[0022] Figure 4 This is an expanded structural diagram of the coating structure of Example 3 of the utility model.

[0023] Among them: 1, supporting part; 2, covering part; 21, hot melt area; 22, grid area; 22a, grid; 23, auxiliary support area; 10, through hole; W1, width of hot melt area; W2, width of grid area; W3, width of auxiliary support area. DETAILED DESCRIPTION

[0024] If certain words are used in the specification and claims to refer to specific components, those skilled in the art should understand that manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" is an open term and should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0025] In the utility model, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to specific circumstances.

[0026] The inventors have found that in sodium-ion square shell batteries, since it is impossible to perform fixture formation, the gas produced by the formation has a serious impact on the performance of the battery cell (the gas cannot be discharged quickly and effectively, which will cause bubble-like sodium precipitation at the negative electrode, affecting the electrical performance and safety performance of the battery cell).

[0027] Moreover, the inventors have also discovered that the currently commonly used Mylar film, when attached to bare cells, will hinder the cell's absorption of electrolyte and the discharge of gas during the formation process. Therefore, it is very necessary to develop a new Mylar film structure to increase the sodium ion bare cell's absorption of electrolyte and ensure that the cell structure can effectively discharge gas during the formation process.

[0028] The following is combined with Figures 1 to 4 The utility model is further described in detail with specific embodiments, but is not intended to limit the utility model.

[0029] Example 1

[0030] A coating structure for a sodium ion battery cell, see Figure 1 , including a supporting portion 1 and a covering portion 2 arranged on opposite sides of the supporting portion 1, a covering space is formed between the two opposite covering portions 2, the covering portion 2 is used to cover the side of the battery cell, the supporting portion 1 is used to support the bottom of the battery cell, and the supporting portion 1 is provided with a plurality of spaced through holes 10 corresponding to and connected to the covering space to promote the electrolyte to penetrate into the covering space from the bottom of the through holes 10, wherein each covering portion 2 has a connected hot melt zone 21 and a grid zone 22, the hot melt zone 21 is used to perform hot melting with the top cover, the grid zone 22 is located between the supporting portion 1 and the hot melt zone 21, and the grid zone 22 is connected to the supporting portion 1. At the same time, in order to ensure that the battery cell placed in the covering space can be efficiently exhausted, the grid zone 22 has a plurality of hollow grids arranged in sequence, and the gas is discharged from the plurality of hollow grids, so that there is no sodium precipitation phenomenon at the fully charged negative electrode interface of the battery cell.

[0031] Preferably, at least one covering portion 2 has an auxiliary supporting area 23 , and the grid area 22 is connected to the supporting portion 1 via the auxiliary supporting area 23 .

[0032] Preferably, the unfolded state of the covering structure is an "I"-shaped structure, with two covering portions 2 of equal size being arranged opposite to the supporting portion 1, the two covering portions 2 being symmetrical along the center line of the supporting portion 1, and each covering portion 2 having a hot melt area 21, a grid area 22 and an auxiliary support area 23 of equal size.

[0033] Preferably, see Figure 2 The hot melt areas 21 of the two opposite covering parts 2 are connected correspondingly, the grid areas 22 of the two opposite covering parts 2 are connected correspondingly, and the auxiliary support areas 23 of the two opposite covering parts 2 are connected correspondingly, so that the shape of the covering structure constitutes a cube or a cylinder, wherein the shape of the covering structure matches the shape of the battery core.

[0034] Preferably, the lengths of the hot melt zone 21 and the mesh zone 22 are equal, the width of the hot melt zone 21 is W1, and the width of the mesh zone 22 is W2, satisfying the relationship: 0.025≤W1 / W2≤0.05, 0.05≤W1 / W2≤0.075, 0.075≤W1 / W2≤0.1, 0.1≤W1 / W2≤0.15 or 0.15≤W1 / W2≤0.2. Among them, the width W1 of the hot melt zone 21 can be 5mm to 8mm, 8mm to 11mm, 11mm to 15mm, and can be specifically 6mm, 10mm or 12mm, etc.

[0035] Preferably, the auxiliary support area 23 and the grid area 22 have the same length, the width of the auxiliary support area 23 is W3, and the width of the grid area 22 is W2, satisfying the relationship: 0.1≤W3 / W2≤0.15, 0.15≤W3 / W2≤0.25, 0.25≤W3 / W2≤0.3 or 0.3≤W3 / W2≤0.35. Among them, the width W3 of the auxiliary support area 23 can be 10mm-15mm, 15mm-20mm, 20mm-30mm, and can be specifically 18mm, 23mm or 28mm.

[0036] Preferably, the thickness of the covering portion 2 is 1 mm to 5 mm, the thickness of the supporting portion 1 is not less than the thickness of the covering portion 2, and the hollow area of ​​each grid can be 0.02 mm 2 ~0.1mm 2 , 0.1mm 2 ~1mm 2 , 1mm 2 ~5mm 2 or 5mm 2 ~10mm 2 .

[0037] Preferably, the grid area 22 has a grid of an ellipse, a circle, a triangle, a sector, a square, a rhombus, a trapezoid, or a regular hexagon.

[0038] Preferably, the area of ​​the through hole 10 is at least 1.05 to 5 times, 5 to 15 times, 15 to 25 times, or 25 to 40 times the hollow area of ​​the grid.

[0039] Preferably, the support portion 1 and the covering portion 2 are both made of corrosion-resistant materials, especially resistant to hydrofluoric acid corrosion.

[0040] Example 2

[0041] Different from Example 1, see Figure 3 A plurality of support portions 1 are disposed at intervals between two opposite covering portions 2. By dividing the support portion 1 into a plurality of support portions 1, with equal or unequal gaps between the plurality of support portions 1, the efficiency of the electrolyte entering the covering space can be effectively improved.

[0042] The other structures of this embodiment are the same as those of Embodiment 1 and will not be described again here.

[0043] Example 3

[0044] Different from Example 1, see Figure 4 The two opposing covering portions 2 may be provided with grids 22a of different shapes, and the grid area 22 of each covering portion 2 may have one or more grids 22a of elliptical, circular, triangular, fan-shaped, square, rhombus, trapezoidal, and regular hexagonal shapes, so as to improve the flexibility of the covering structure for on-demand exhaust.

[0045] The other structures of this embodiment are the same as those of Embodiment 1 and will not be described again here.

[0046] Example 4

[0047] Different from Embodiment 1 or 3, the supporting portion 1 can have two or more pairs of relative covering portions 2. In the covering structure, the hot melt areas 21 of two adjacent covering portions 2 are correspondingly connected, the grid areas 22 of two adjacent covering portions 2 are correspondingly connected, and the auxiliary support areas 23 of two adjacent covering portions 2 are correspondingly connected, so that the shape of the covering structure matches the shape of the required battery cell.

[0048] The other structures of this embodiment are the same as those of Embodiment 1 or 3 and will not be described again here.

[0049] Example 5

[0050] A secondary battery comprises a battery cell and the coating structure of any one of embodiments 1 to 4, wherein the battery cell is arranged in the coating space of the coating structure.

[0051] By maximizing the absorption of electrolyte by bare cells and promoting the discharge of gas during the formation process, it is possible to ensure that the cells have high rate performance, high cycle performance and high safety performance, thereby forming a highly safe EV cell and energy storage battery. The battery may be a sodium ion square shell battery 71H3204.

[0052] Obviously, the utility model avoids the serious situation of bubble-like sodium precipitation at the fully charged negative electrode interface of the sodium ion square shell battery with Mylar film of traditional structure. At the same time, the Mylar film of traditional structure has a certain influence on the electrical properties such as the internal resistance and capacity of the battery cell, and there are certain safety hazards. The grid area 22 of the present scheme has a plurality of hollow grids 22a arranged in sequence, and the gas is discharged from the plurality of hollow grids 22a, so that there is no sodium precipitation phenomenon at the fully charged negative electrode interface of the battery cell, thereby effectively improving the service life and operation safety of the battery.

[0053] According to the disclosure and teaching of the above description, those skilled in the art to which the utility model belongs can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the utility model.

Claims

1. A coating structure for a sodium ion battery cell, characterized in that: include: A supporting portion (1) and a covering portion (2) disposed on two opposite sides of the supporting portion (1); A covering space is formed between the two opposite covering parts (2); The support portion (1) is provided with a plurality of through holes (10) arranged at intervals and correspondingly communicating with the covering space; Each of the covering portions (2) has a connected hot-melt zone (21) and a mesh zone (22), the mesh zone (22) being located between the supporting portion (1) and the hot-melt zone (21), and the mesh zone (22) having a plurality of hollow meshes (22a) arranged in sequence.

2. The coating structure of the sodium ion battery cell according to claim 1, characterized in that: At least one of the covering portions (2) has an auxiliary support area (23), and the grid area (22) is connected to the supporting portion (1) via the auxiliary support area (23).

3. The coating structure of the sodium ion battery cell according to claim 1 or 2, characterized in that: The hollow area of ​​each grid (22a) is 0.02mm 2 ~10mm 2 .

4. The coating structure of the sodium ion battery cell according to claim 1 or 2, characterized in that: The grid area (22) has a grid (22a) of one or more shapes selected from the group consisting of an ellipse, a circle, a triangle, a sector, a square, a rhombus, a trapezoid, and a regular hexagon.

5. The coating structure of the sodium ion battery cell according to claim 1 or 2, characterized in that: The lengths of the hot melt zone (21) and the grid zone (22) are equal, the width of the hot melt zone (21) is W1, and the width of the grid zone (22) is W2, satisfying the relationship: 0.025≤W1 / W2≤0.

2.

6. The coating structure of the sodium ion battery cell according to claim 2, characterized in that: The auxiliary support area (23) and the grid area (22) are of equal length, the width of the auxiliary support area (23) is W3, and the width of the grid area (22) is W2, satisfying the relationship: 0.1≤W3 / W2≤0.

35.

7. The coating structure of the sodium ion battery cell according to claim 3, characterized in that: The area of ​​the through hole (10) is at least 1.05 to 40 times the hollow area of ​​the grid (22a).

8. The coating structure of the sodium ion battery cell according to claim 1 or 2, characterized in that: The thickness of the supporting portion (1) is not less than the thickness of the covering portion (2), and a plurality of the supporting portions (1) are arranged at intervals between two opposite covering portions (2).

9. The coating structure of the sodium ion battery cell according to claim 1 or 2, characterized in that: The hot melt areas (21) of two opposite covering parts (2) are connected correspondingly, and the mesh areas (22) of two opposite covering parts (2) are connected correspondingly; or the hot melt areas (21) of two adjacent covering parts (2) are connected correspondingly, and the mesh areas (22) of two adjacent covering parts (2) are connected correspondingly.

10. A secondary battery, characterized in that: It comprises a battery cell and a coating structure as claimed in any one of claims 1 to 9, wherein the battery cell is arranged in the coating space.

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