Sealing sheet, sealing structure, battery cell and battery pack

Abstract

The utility model provides a sealing piece, a sealing structure, a battery cell and a battery pack, the sealing piece comprises a top surface and a bottom surface which are opposite to each other, the bottom surface is provided with a first groove, the sealing piece is provided with an air passage, and the air passage is communicated with the first groove; the gas channel is used for discharging gas, the cavity is formed between the first groove and the top cover, gas generated by welding flows into the cavity and is discharged through the gas channel, and gas trapping in welding is avoided.

Description

Technical Field

[0001] This utility model relates to the field of power battery technology, specifically to a sealing sheet, a sealing structure, a battery cell, and a battery pack. Background Technology

[0002] In related technologies, the sealing structure of batteries is usually formed by stamping and bending. Its characteristics are simple forming process, high spring stress, low structural strength and poor dimensional consistency, which affect the sealing strength of the battery and lead to battery leakage. In addition, gas is generated during the welding process between the sealing sheet and the top cover. The gas is easily trapped under the sealing sheet and is not easy to escape, resulting in gas trapping during welding and affecting the welding quality.

[0003] Therefore, the sealing sheet in the relevant technology has the technical problem of trapped gas during welding. Utility Model Content

[0004] The embodiments of this utility model provide a sealing sheet, a sealing structure, a battery cell, and a battery pack, which can improve the technical problem of welding gas trapping in the sealing sheet in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a sealing sheet for sealing a battery cell, comprising a top surface and a bottom surface opposite to each other, wherein the bottom surface is provided with a first groove, and wherein the sealing sheet is provided with an air passage that communicates with the first groove.

[0006] In one embodiment, the air passage is located on the bottom surface and extends through the sidewall of the first groove.

[0007] In one embodiment, the sealing sheet is provided with a plurality of air channels, which are arranged evenly around the first groove.

[0008] In one embodiment, the sealing sheet includes a central dense portion, a loose portion surrounding the central dense portion, and an edge dense portion surrounding the loose portion. The pressure resistance of the central dense portion is greater than that of the loose portion, and the pressure resistance of the edge dense portion is greater than that of the loose portion. The central dense portion forms the top wall of the first groove, and the edge dense portion is used for welding to the top cover of the battery cell.

[0009] In one embodiment, the compressive strength of the intermediate dense portion is P, the tensile strength of the sealing sheet material is T, and the thickness of the intermediate dense portion is t millimeters, wherein (10 -3 ×T)t≤P≤(2×T)t.

[0010] In one embodiment, the thickness t of the intermediate dense portion satisfies: 0.1 mm ≤ t ≤ 1 mm.

[0011] In one embodiment, the intermediate dense portion, the loose portion, and the edge dense portion have a continuous tissue texture structure.

[0012] In one embodiment, the top surface is provided with a second groove, the middle dense portion and the loose portion together form the bottom wall of the second groove, and the edge dense portion forms the side wall of the second groove.

[0013] In one embodiment, the angle between the sidewall of the second groove and the bottom surface of the second groove ranges from 90 degrees to 165 degrees.

[0014] Secondly, embodiments of this utility model provide a sealing structure, including a top cover, a sealing particle, and a sealing sheet as described in any of the above embodiments. The top cover has a through hole, the sealing particle is used to block the through hole, and the sealing sheet is connected to the top cover to seal the sealing particle.

[0015] In one embodiment, the bottom surface of the sealing sheet faces the through hole, and a cavity is formed between the first groove of the sealing sheet and the top cover, the cavity being in communication with the air passage.

[0016] Thirdly, embodiments of this utility model provide a battery cell, including a sealing sheet as described in any of the above embodiments, or a sealing structure as described in any of the above embodiments.

[0017] Fourthly, embodiments of the present invention provide a battery pack, including a sealing sheet as described in any of the above embodiments, or a sealing structure as described in any of the above embodiments, or a battery cell as described in the above embodiments.

[0018] The beneficial effects of the embodiments of this utility model are as follows:

[0019] In an embodiment of this utility model, a first groove is provided on the bottom surface of the sealing sheet, and an air passage is opened in communication with the first groove. The air passage is used to discharge gas. A cavity is formed between the first groove on the bottom surface of the sealing sheet and the top cover. The cavity is in communication with the air passage. When the gas generated during welding flows into the cavity, it can be discharged through the air passage, thus avoiding gas trapping during welding. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1This is a three-dimensional schematic diagram of the sealing sheet provided in an embodiment of the present invention from a first-view perspective;

[0022] Figure 2 This is a three-dimensional schematic diagram of the sealing sheet provided in an embodiment of the present invention from a second perspective;

[0023] Figure 3 This is a cross-sectional schematic diagram of the sealing sheet provided in an embodiment of this utility model;

[0024] Figure 4 This is an exploded view of the sealing structure provided in an embodiment of this utility model;

[0025] Figure 5 This is a cross-sectional schematic diagram of the sealing structure provided in an embodiment of this utility model. Detailed Implementation

[0026] 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. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0027] Furthermore, the terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different technical features. The terms "multiple" and similar words indicate two or more unless otherwise expressly specified.

[0028] Please see Figure 1 , Figure 2 , Figure 3 The sealing sheet 1 provided in the embodiment of this utility model includes a top surface 10 and a bottom surface 20 opposite to each other. The bottom surface 20 is provided with a first groove 30. The sealing sheet 1 is provided with an air passage 40, which communicates with the first groove 30.

[0029] The diameter of the top surface 10 can be larger than the diameter of the bottom surface 20, and the bottom surface of the sealing sheet is narrower to facilitate the assembly of the sealing sheet and the battery cell.

[0030] In this embodiment, a first groove 30 is provided on the bottom surface 20 of the sealing sheet 1, and an air passage 40 is opened in communication with the first groove 30. The air passage 40 is used to discharge gas. A cavity is formed between the first groove 30 on the bottom surface 20 of the sealing sheet 1 and the top cover 90. The cavity is in communication with the air passage 40. When the gas generated during welding flows into the cavity, it can be discharged through the air passage 40, which avoids gas trapping during welding and alleviates the technical problem of gas trapping during welding in the prior art.

[0031] The technical solution of this application will now be described in conjunction with specific embodiments.

[0032] In one embodiment, please refer to Figure 1 The air passage 40 is located on the bottom surface 20 and penetrates the side wall of the first groove 30.

[0033] Among them, the airway 40 is a groove structure, and the opening direction of the groove structure is from the top surface 10 to the bottom surface 20.

[0034] It is understandable that the air passage 40 can be formed on the bottom surface 20 and penetrate the side wall of the first groove 30 and communicate with the outside, so that the air passage 40 can discharge the gas in the first groove below the bottom surface 20 of the sealing sheet 1 and avoid gas trapping during welding.

[0035] In this embodiment, by opening an air passage 40 on the bottom surface 20, the trapped air in the cavity below the sealing sheet 1 is discharged through the air passage 40. On the one hand, the process of opening the air passage 40 on the bottom surface 20 is simple. On the other hand, the air passage 40 penetrates the side wall, which is conducive to the discharge of gas generated during welding through the air passage 40, further avoiding trapped gas during welding.

[0036] In one embodiment, please refer to Figure 1 The sealing sheet 1 is provided with multiple air channels 40, which surround the first groove 30 and are evenly arranged.

[0037] The number of airways 40 is four or eight, and adjacent airways 40 are arranged at equal intervals.

[0038] The multiple airways 40 are all the same size, and the size includes at least one of the depth, length and width of the airway 40.

[0039] It is understandable that the gas generated during welding is discharged through the nearest gas channel 40. Setting the gas channels 40 to be evenly distributed is conducive to gas discharge. Furthermore, setting the gas channels 40 to four or eight and evenly distributed ensures that there is at least one nearby gas channel 40 for any welding point to facilitate gas discharge.

[0040] It should be noted that the existence of at least one nearby vent 40 at any welding point means that, relative to the center of the circle around which the multiple welding points are located, within a range of 90 degrees clockwise or counterclockwise along the line connecting the welding point and the center, there is at least one vent 40 for discharging the gas generated during welding at that welding point.

[0041] In this embodiment, by arranging the air passages 40 evenly around the first groove 30, it is beneficial to discharge the gas generated during welding.

[0042] In one embodiment, please refer to Figure 3 The sealing sheet 1 includes a central dense portion 60, a loose portion 70 surrounding the central dense portion 60, and an edge dense portion 80 surrounding the loose portion 70. The pressure resistance of the central dense portion 60 is greater than that of the loose portion 70, and the pressure resistance of the edge dense portion 80 is greater than that of the loose portion 70. The central dense portion 60 forms the top wall of the first groove 30, and the edge dense portion 80 is used for welding to the top cover 90.

[0043] The loose portion 70 can serve as the sidewall of the first groove 30 and surround the dense portion 60 in the middle to form the first groove 30.

[0044] In this application, the withstand voltage strength refers to the strength under the action of air pressure inside the battery cell; the withstand voltage refers to the ability to withstand the air pressure inside the battery cell.

[0045] The height of the dense edge portion 80 is greater than the height of the loose portion 70, which creates a step difference between the top surface of the dense edge portion 80 and the top surface of the loose portion 70. When the dense edge portion 80 is welded, it flows in a molten state and fills the step difference, thus preventing the dense edge portion 80 from forming a protruding structure during welding and affecting the flatness of the top surface 10 of the sealing sheet 1, thereby improving the flatness of the top surface 10 of the sealing sheet 1.

[0046] It is understandable that by setting the edge dense portion 80 for welding, the first groove 30 is formed by the loose portion 70 and the middle dense portion 60 surrounding it, thus avoiding the welding position from affecting the formation of the first groove 30.

[0047] In this embodiment, the sealing sheet 1 is divided into a central dense portion 60, a loose portion 70 surrounding the central dense portion 60, and an edge dense portion 80 surrounding the loose portion 70. The edge dense portion 80 is welded to the top cover 90. The loose portion 70 and the central dense portion 60 form a first groove 30, which avoids the welding position from affecting the formation of the first groove 30 and ensures the flatness of the top surface 10 of the sealing sheet 1.

[0048] In one embodiment, the compressive strength of the intermediate dense portion 60 is P, the tensile strength of the sealing sheet 1 is T, and the thickness of the intermediate dense portion 60 is t millimeters, wherein (10 -3 ×T)t≤P≤(2×T)t.

[0049] Where 20≤T≤200.

[0050] The tensile strength T of the material of the sealing sheet 1 can be any one of 20, 50, 100, 150, or 200.

[0051] Understandably, under the premise of controlling variables, the compressive strength P of the intermediate dense part 60 increases with the increase of the tensile strength T of the sealing sheet 1 material. Similarly, the compressive strength P of the intermediate dense part 60 increases with the increase of the thickness t of the intermediate dense part 60.

[0052] In one embodiment, the thickness t of the intermediate dense portion 60 satisfies: 0.1 mm ≤ t ≤ 1 mm.

[0053] The thickness t of the intermediate dense portion 60 can be any one of 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, or 1 mm.

[0054] Understandably, when the thickness of the intermediate dense portion 60 is greater than 1 mm, the top surface 10 of the intermediate dense portion 60 will exceed the plane of the top cover 90, making the intermediate dense portion 60 convex, which is not conducive to the assembly of the top insulating sheet of the battery cell; when the thickness of the intermediate dense portion 60 is less than 0.1 mm, the withstand voltage of the intermediate dense portion 60 is insufficient, making the intermediate dense portion 60 prone to deformation, which will also affect subsequent assembly.

[0055] In this embodiment, by ensuring that the thickness t of the intermediate dense portion 60 satisfies: 0.1 mm ≤ t ≤ 1 mm, on the one hand, the intermediate dense portion 60 can be prevented from deforming due to insufficient withstand voltage strength, and on the other hand, the intermediate dense portion 60 can be prevented from being convex, which would affect the subsequent assembly of the top insulating sheet of the battery cell.

[0056] In one embodiment, please refer to Figure 3 The dense middle portion 60, the loose portion 70, and the dense edge portion 80 have a continuous tissue texture structure.

[0057] The dense middle portion 60, the loose portion 70, and the dense edge portion 80 can be integrally formed.

[0058] The sealing sheet 1 can be formed by upsetting process.

[0059] Understandably, metallographic analysis reveals that the material texture of the dense edge area, the loose portion 70, and the dense middle area is continuous. No obvious discontinuities are observed in the texture structure between the dense edge area, the dense middle area, and the loose portion 70. The continuous texture structure is beneficial to improving the structural strength of the sealing sheet 1.

[0060] In this embodiment, by making the middle dense portion 60, the loose portion 70 and the edge dense portion 80 have a continuous texture structure, the structural strength of the sealing sheet 1 is improved and deformation of the sealing sheet 1 is avoided.

[0061] In one embodiment, please refer to Figure 2 The top surface 10 is provided with a second groove 50, the middle dense part 60 and the loose part 70 together form the bottom wall of the second groove 50, and the edge dense part 80 forms the side wall of the second groove 50.

[0062] The first groove 30 and the second groove 50 can share the same center line.

[0063] The first groove 30 and the second groove 50 are at least partially overlapping in the thickness direction of the sealing sheet 1.

[0064] It is understandable that the top surface 10 has a second groove 50, and the dense edge portion 80 and the loose edge portion 70 form a height difference, which is beneficial to the leveling of the dense edge portion 80, which is in a molten state during welding.

[0065] In one embodiment, please refer to Figure 2 The angle between the sidewall of the second groove 50 and the bottom surface 20 of the second groove 50 ranges from 90 degrees to 165 degrees.

[0066] The included angle between the sidewall of the second groove 50 and the bottom surface 20 of the second groove 50 can be any one of 90 degrees, 105 degrees, 120 degrees, 135 degrees, 150 degrees, and 165 degrees.

[0067] It is understandable that the larger the angle between the sidewall of the second groove 50 and the bottom surface 20 of the second groove 50, the smaller the drop between the sidewall of the second groove 50 and the bottom surface 20 of the second groove 50 will be when the width of the bottom surface 20 of the second groove 50 remains unchanged. This is not conducive to the leveling of the dense edge part 80 in a molten state during welding, and it is easy to make the top surface 10 of the sealing sheet 1 bulge, which will affect the subsequent assembly.

[0068] It is understandable that when the angle between the sidewall of the second groove 50 and the bottom surface 20 of the second groove 50 is greater than 165 degrees, it is not conducive to the leveling of the dense edge portion 80 in a molten state during welding; when the angle between the sidewall of the second groove 50 and the bottom surface 20 of the second groove 50 is less than 90 degrees, the second groove 50 is not easy to manufacture, which increases the process cost.

[0069] In this embodiment, by limiting the angle range between the sidewall of the second groove 50 and the bottom surface 20 of the second groove 50 to 90 degrees to 165 degrees, on the one hand, the second groove 50 is easy to prepare, reducing the cost of the preparation process; on the other hand, it is beneficial to the leveling of the dense edge portion 80 in a molten state during welding, which facilitates subsequent assembly.

[0070] In one embodiment, the sidewall of the first groove 30 is formed with at least two air passages 40, the air passages 40 penetrating the sidewall of the first groove 30, and the two air passages 40 include at least one air inlet passage 40 and at least one air outlet passage 40.

[0071] The opening of the first groove 30 faces the bottom surface 20 along the top surface 10.

[0072] The air intake duct 40 and the air outlet duct 40 can be arranged relative to each other.

[0073] It is understandable that the air inlet 40 is the air inlet 40 close to the welding point, and the air outlet 40 is the air outlet 40 far away from the welding point. When the welding point changes, the corresponding air inlet 40 will also change. When welding is performed on the welding point of the sealing sheet 1, the gas generated by welding will be discharged into the cavity through the air inlet 40 adjacent to the welding point, and discharged through other air inlets 40.

[0074] In this embodiment, by forming at least two air passages 40, one air inlet 40 near the welding point is used to discharge the gas generated during welding into the first groove 30, and the other air outlet 40 away from the welding point is used to discharge the gas in the first groove 30. Compared with only one air passage 40, the efficiency of air intake and exhaust is improved, and the conflict between air intake and exhaust in the same air passage 40 at the same time is avoided. This prevents the gas in the cavity formed by the first groove 30 from being discharged in time and forming a greater pressure in the cavity than the outside, so that the gas generated during welding cannot be discharged smoothly into the cavity and cannot be discharged in time, resulting in trapped gas during welding and affecting the quality of welding.

[0075] In one embodiment, please refer to Figure 2 The sealing sheet 1 also includes a positioning hole structure, which is located at the center of the top surface 10.

[0076] The positioning hole structure is located on the bottom surface 20 of the second groove 50.

[0077] The sidewall of the second groove 50 can be arranged around the positioning hole structure.

[0078] The positioning hole structure is used to position the sealing sheet 1 during welding, thereby reducing assembly errors.

[0079] Secondly, please refer to Figure 4 and Figure 5 The present invention provides a sealing structure including a top cover 90, a sealing particle 3 and a sealing sheet 1. The top cover 90 is provided with a through hole 100. The sealing particle 3 is used to block the through hole 100. The sealing sheet 1 is connected to the top cover 90 to cover the sealing particle 3.

[0080] The sealing structure also includes an injection hole structure 2, which includes a through hole 100 and a top cover 90.

[0081] In one embodiment, please refer to Figure 5 The bottom surface 20 of the sealing sheet 1 faces the through hole 100, and a cavity is formed between the first groove 30 of the sealing sheet 1 and the top cover 90, and the cavity is connected to the air passage 40.

[0082] The first groove 30 of the sealing sheet 1 is used to form a cavity between it and the top cover 90 for accommodating the gas generated during welding. The formation of the first groove 30 increases the gas volume that the cavity can accommodate.

[0083] Thirdly, embodiments of the present invention provide a battery cell, including a sealing sheet 1 as described in any of the above embodiments, or a sealing structure as described in any of the above embodiments.

[0084] Fourthly, embodiments of the present invention provide a battery pack, including a sealing sheet 1 as described in any of the above embodiments, or a sealing structure as described in any of the above embodiments, or a battery cell as described in the above embodiments.

[0085] This application forms a first groove 30 on the bottom surface 20 of the sealing sheet 1 and provides an air passage 40 on the sealing sheet 1. One end of the air passage 40 is connected to the first groove 30 and the other end of the air passage 40 is connected to the outside. A cavity is formed between the sealing sheet 1 and the top cover 90 of the battery cell. When the sealing sheet 1 and the top cover 90 are connected by welding, the gas generated by welding will first enter the cavity and then be discharged from the cavity through the air passage 40, thereby avoiding welding gas trapping.

[0086] The function of the air passage 40 provided in the sealing sheet 1 is as follows: on the one hand, the air passage 40 facilitates the discharge of gas generated during welding into the cavity; on the other hand, the air passage 40 also facilitates the timely discharge of gas from the cavity, thus avoiding gas trapping during welding.

[0087] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A sealing sheet for sealing a battery cell, characterized in that, It includes a top surface and a bottom surface, the bottom surface being provided with a first groove, wherein the sealing sheet is provided with an air passage, the air passage communicating with the first groove; The sealing sheet includes a central dense portion, a loose portion surrounding the central dense portion, and an edge dense portion surrounding the loose portion. The pressure resistance of the central dense portion is greater than that of the loose portion, and the pressure resistance of the edge dense portion is greater than that of the loose portion. The central dense portion forms the top wall of the first groove, and the edge dense portion is used for welding to the top cover of the battery cell.

2. The sealing sheet according to claim 1, characterized in that, The air passage is located on the bottom surface and extends through the side wall of the first groove.

3. The sealing sheet according to claim 2, characterized in that, The sealing sheet is provided with a plurality of air channels, which are arranged evenly around the first groove.

4. The sealing sheet according to claim 1, characterized in that, The compressive strength of the intermediate dense portion is P, the tensile strength of the sealing sheet material is T, and the thickness of the intermediate dense portion is t millimeters, wherein (10 -3 ×T)t≤P≤(2×T)t.

5. The sealing sheet according to claim 4, characterized in that, The thickness t of the intermediate dense portion satisfies: 0.1 mm ≤ t ≤ 1 mm.

6. The sealing sheet according to claim 1, characterized in that, The intermediate dense portion, the loose portion, and the edge dense portion have a continuous tissue texture structure.

7. The sealing sheet according to claim 1, characterized in that, The top surface is provided with a second groove, the middle dense portion and the loose portion together form the bottom wall of the second groove, and the edge dense portion forms the side wall of the second groove.

8. The sealing sheet according to claim 7, characterized in that, The angle between the sidewall of the second groove and the bottom surface of the second groove ranges from 90 degrees to 165 degrees.

9. A sealing structure, characterized in that, The device includes a top cover, a sealing element, and a sealing sheet as described in any one of claims 1 to 8, wherein the top cover has a through hole, the sealing element is used to block the through hole, and the sealing sheet is connected to the top cover to cover the sealing element.

10. The sealing structure according to claim 9, characterized in that, The bottom surface of the sealing sheet faces the through hole, and a cavity is formed between the first groove of the sealing sheet and the top cover, and the cavity communicates with the air passage.

11. A battery cell, characterized in that, It includes the sealing sheet as described in any one of claims 1 to 8, or the sealing structure as described in any one of claims 9 to 10.

12. A battery pack, characterized in that, It includes the sealing sheet as described in any one of claims 1 to 8, or the sealing structure as described in any one of claims 9 to 10, or the battery cell as described in claim 11.

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