Sealing element, lithium battery cover plate structure and lithium battery

Abstract

The utility model provides a sealing element, lithium battery cover plate structure and lithium battery, the sealing element is used for sealing the liquid injection hole of the lithium battery cover plate structure, the lithium battery cover plate structure is covered on the battery module and forms the lithium battery cavity with the battery module, the liquid injection hole is communicated with the lithium battery cavity, the sealing element comprises a sealing body, a sealing part and a sealing part, the sealing body is provided with a sealing part used for being sealed in the liquid injection hole. Wherein the sealing part is provided with a pressure relief concave part, and the pressure relief concave part is sunken in the extending direction of the liquid injection hole, so that when the pressure value of gas in the lithium battery cavity exceeds a threshold value, the gas in the lithium battery cavity penetrates through the position, provided with the pressure relief concave part, of the sealing part under the action of gas pressure, so as to relieve the pressure of the lithium battery cavity; the sealing element provided by the utility model solves the problems of complicated structure and higher production cost of the lithium battery cover plate in the prior art.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and in particular to a sealing component, a lithium battery cover plate structure and a lithium battery. Background Art

[0002] Most lithium battery covers are provided with injection holes and explosion-proof holes. The injection holes are sealed by setting a sealing sheet on the injection holes, and explosion-proof films are set on the explosion-proof holes for explosion-proof purposes. Most explosion-proof films are made of copper foil or aluminum foil. The explosion-proof principle of the explosion-proof film is as follows: when a lithium-ion battery is overcharged or short-circuited, gas is generated inside the battery and the battery pressure increases. When the gas pressure exceeds the set pressure of the explosion-proof film, the explosion-proof film ruptures, and the gas and energy in the battery are released, reducing the risk of battery explosion.

[0003] However, the lithium battery cover has both injection holes and explosion-proof holes, which not only deteriorates the reliability and stability of the lithium battery cover due to too many holes, but also complicates the structure of the lithium battery and increases the production cost of the lithium battery cover. Utility Model Content

[0004] The main purpose of the utility model is to provide a sealing member, a lithium battery cover plate structure and a lithium battery, so as to solve the problems of complex structure and high production cost of the lithium battery cover plate in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the utility model, a seal is provided for sealing the injection hole of a lithium battery cover structure, the lithium battery cover structure is covered on the battery module and surrounds the battery module to form a lithium battery cavity, the injection hole is connected to the lithium battery cavity, and the seal comprises: a sealing body, the sealing body having a sealing portion for sealing in the injection hole; wherein a pressure relief recess is provided on the sealing portion, the pressure relief recess is recessed along the extension direction of the injection hole, so that when the pressure value of the gas in the lithium battery cavity exceeds a threshold value, the gas in the lithium battery cavity passes through the position of the sealing portion with the pressure relief recess under the action of air pressure to relieve the pressure of the lithium battery cavity.

[0006] Furthermore, the sealing part includes a sealing cover, which has a first end face and a second end face arranged opposite to each other along the extension direction of the injection hole. A groove is provided on the first end face or the second end face, and the groove is recessed toward the inner side of the sealing cover along the extension direction of the injection hole to form a pressure relief recess.

[0007] Furthermore, a plurality of grooves are formed on both the first end surface and the second end surface, and the plurality of grooves on the first end surface and the plurality of grooves on the second end surface are arranged in a one-to-one correspondence with each other.

[0008] Furthermore, the groove is an annular groove; and / or the groove is a polygonal groove.

[0009] Further, the depth of the groove along the extending direction of the liquid injection hole is d, and the depth of the sealing cover along the extending direction of the liquid injection hole is S, wherein 1 / 8S≤d≤1 / 3S.

[0010] Furthermore, the injection hole includes a first injection hole segment and a second injection hole segment which are interconnected, the first injection hole segment is located on a side of the second injection hole segment away from the lithium battery cavity, the first injection hole segment and the second injection hole segment are both cylindrical holes, the flow cross-section of the first injection hole segment is larger than the flow cross-section of the second injection hole segment, the axis of the first injection hole segment is arranged to coincide with the axis of the second injection hole segment, and the sealing portion is used to seal in the first injection hole segment.

[0011] Furthermore, the second end face is located on the side of the first end face close to the lithium battery cavity, the first end face and the second end face are both circular, the diameter of the second end face is smaller than the diameter of the first end face, and the side wall of the sealing cover abuts against the hole wall of the first injection hole section of the injection hole to seal the injection hole.

[0012] Furthermore, the sealing member is integrally formed by injection molding.

[0013] According to the second aspect of the utility model, a lithium battery cover plate structure is provided, including the above-mentioned sealing member, the lithium battery cover plate structure also includes a substrate, the substrate includes two end surfaces relatively arranged along a first preset direction, the injection hole extends along the first preset direction and passes through the two end surfaces, and the sealing member is used to seal the injection hole.

[0014] According to the third aspect of the utility model, a lithium battery is provided, comprising the above-mentioned lithium battery cover plate structure and a battery module, wherein the base plate cover is arranged on the battery module and surrounds the battery module to form a lithium battery cavity, and the injection hole is connected to the lithium battery cavity.

[0015] According to the technical solution of the utility model, the sealing member includes a sealing body, which has a sealing portion for sealing in the injection hole, and a pressure relief recess is arranged on the sealing portion, which is recessed along the extension direction of the injection hole. The arrangement of the pressure relief recess reduces the thickness of the sealing portion at the position having the pressure relief recess, so that when the pressure value of the gas in the lithium battery cavity exceeds a threshold value, the gas in the lithium battery cavity passes through the position having the pressure relief recess of the sealing portion under the action of air pressure to relieve the pressure of the lithium battery cavity and prevent the lithium battery from exploding. Therefore, the injection hole can be used as an explosion-proof hole, so that there is no need to open an explosion-proof hole on the lithium battery cover plate structure to relieve the pressure of the lithium battery, thereby solving the problems of complex structure and high production cost of the lithium battery cover plate in the prior art, simplifying the structure of the lithium battery cover plate, and reducing the production cost of the lithium battery cover plate and the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0017] Figure 1 A structural schematic diagram of an embodiment of a lithium battery cover plate structure according to the utility model is shown;

[0018] Figure 2 A schematic structural diagram of an embodiment of a sealing portion of a sealing member according to the present utility model is shown;

[0019] Figure 3 A cross-sectional view showing an embodiment of a sealing portion of a sealing member according to the present invention;

[0020] Figure 4 An axonometric view showing an embodiment of a sealing portion of a seal according to the present invention;

[0021] Figure 5 A structural schematic diagram of an embodiment of a sealing pin of a sealing member according to the utility model is shown.

[0022] The above drawings include the following reference numerals:

[0023] 1. Liquid injection hole; 11. Sealing body; 111. Sealing part; 12. Pressure relief recess; 120. Sealing cover; 130. Sealing ring; 112. First end face; 113. Second end face; 114. Groove; 2. First liquid injection hole section; 3. Second liquid injection hole section; 60. Sealing pin; 70. Base plate; 80. Tab; 90. Stop frame; 61. Sealing pin end; 62. Sealing pin pin. DETAILED DESCRIPTION

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0026] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0027] The utility model provides a sealing member, please refer to Figures 1 to 5 , used to seal the injection hole 1 of the lithium battery cover structure, the lithium battery cover structure is covered on the battery module and surrounds the battery module to form a lithium battery cavity, the injection hole 1 is connected to the lithium battery cavity, and the sealing member includes: a sealing body 11, the sealing body 11 has a sealing portion 111 for sealing in the injection hole 1; wherein, a pressure relief recess 12 is provided on the sealing portion 111, and the pressure relief recess 12 is recessed along the extension direction of the injection hole 1, so that when the pressure value of the gas in the lithium battery cavity exceeds a threshold value, the gas in the lithium battery cavity passes through the position of the sealing portion 111 with the pressure relief recess 12 under the action of air pressure to relieve the pressure of the lithium battery cavity.

[0028] The sealing member of the utility model comprises a sealing body 11, which has a sealing portion 111 for sealing in the liquid injection hole 1, and a pressure relief recess 12 is arranged on the sealing portion 111, and the pressure relief recess 12 is recessed along the extension direction of the liquid injection hole 1. The arrangement of the pressure relief recess 12 reduces the thickness of the sealing portion 111 at the position having the pressure relief recess 12, so that when the pressure value of the gas in the lithium battery cavity exceeds the threshold value, the gas in the lithium battery cavity passes through the position having the pressure relief recess 12 of the sealing portion 111 under the action of the air pressure, so as to relieve the pressure of the lithium battery cavity and prevent the lithium battery from exploding. Therefore, the liquid injection hole 1 can be used as an explosion-proof hole, so that there is no need to open an explosion-proof hole on the lithium battery cover plate structure to relieve the pressure of the lithium battery, thereby solving the problems of complex structure and high production cost of the lithium battery cover plate in the prior art, simplifying the structure of the lithium battery cover plate, and reducing the production cost of the lithium battery cover plate and the lithium battery.

[0029] Specifically, when the pressure value of the gas in the lithium battery cavity is less than or equal to the threshold value, the sealing portion 111 is sealed in the injection hole 1 to seal the injection hole 1 to prevent the electrolyte and gas in the lithium battery cavity from escaping.

[0030] In this embodiment, if Figure 2 As shown, the sealing portion 111 includes a sealing cover 120, which has a first end face 112 and a second end face 113 that are relatively arranged along the extension direction of the injection hole 1, and a groove 114 is opened on the first end face 112 or the second end face 113, and the groove 114 is recessed toward the inner side of the sealing cover 120 along the extension direction of the injection hole 1 to form a pressure relief recess 12.

[0031] Specifically, a groove 114 is provided on any one of the first end face 112 and the second end face 113, and the groove 114 is recessed toward the inner side of the sealing cover 120 along the extension direction of the injection hole 1 to form a pressure relief recess 12, thereby reducing the thickness of the sealing cover 120 where the groove 114 is located, so that when the pressure value of the gas in the lithium battery cavity exceeds a threshold value, the gas in the lithium battery cavity passes through the position of the sealing cover 120 with the groove 114 under the action of air pressure.

[0032] In this embodiment, if Figure 3 As shown, a plurality of grooves 114 are provided on both the first end face 112 and the second end face 113, and the plurality of grooves 114 on the first end face 112 and the plurality of grooves 114 on the second end face 113 are arranged one by one in correspondence with each other. Such an arrangement further reduces the thickness of the sealing cover 120 where the grooves 114 are located, and further facilitates that when the pressure value of the gas in the lithium battery cavity exceeds a threshold value, the gas in the lithium battery cavity passes through the position of the sealing cover 120 with the grooves 114 under the action of the gas pressure.

[0033] In this embodiment, if Figure 2 As shown, the groove 114 is an annular groove; and / or, the groove 114 is a polygonal groove. Such a setting ensures the concave area of ​​the groove 114, and avoids the sealing cover 120 with the groove 114 from being too small, resulting in the gas in the lithium battery cavity not being able to pass through the sealing cover 120 in time and escaping to the outside, causing the battery to explode. Among them, the groove 114 is a polygonal groove means that the cross section of the groove 114 is a polygon.

[0034] In this embodiment, if Figure 3 As shown, the depth of the groove 114 along the extension direction of the injection hole 1 is d, and the depth of the sealing cover 120 along the extension direction of the injection hole 1 is S, where 1 / 8S≤d≤1 / 3S. This arrangement avoids the situation where the depth of the groove 114 along the extension direction of the injection hole 1 is too small, resulting in a larger thickness of the sealing cover 120 with the groove 114, causing the gas in the lithium battery cavity to fail to pass through the sealing cover 120 in time and escape to the outside, resulting in battery explosion.

[0035] In this embodiment, if Figure 1 As shown, the injection hole 1 includes a first injection hole segment 2 and a second injection hole segment 3 which are interconnected. The first injection hole segment 2 is located on a side of the second injection hole segment 3 away from the lithium battery cavity. The first injection hole segment 2 and the second injection hole segment 3 are both cylindrical holes. The flow cross-section of the first injection hole segment 2 is larger than the flow cross-section of the second injection hole segment 3. The axis of the first injection hole segment 2 is arranged to coincide with the axis of the second injection hole segment 3. The sealing portion 111 is used to seal in the first injection hole segment 2.

[0036] Specifically, the two ends of the second injection hole segment 3 are respectively connected to the lithium battery cavity and the first injection hole segment 2, and the sealing portion 111 is used to seal in the first injection hole segment 2 to prevent the gas and electrolyte in the lithium battery cavity from escaping to the outside from the second injection hole segment 3 and the first injection hole segment 2 in turn.

[0037] Specifically, Figure 4 As shown, the sealing portion 111 also includes a sealing ring 130, which is arranged on the second end surface 113 and extends along the extension direction of the injection hole 1 toward the direction close to the lithium battery cavity. The sealing ring 130 is covered on the second injection hole segment 3 to further seal the second injection hole segment 3.

[0038] In this embodiment, if Figure 4 As shown, the second end face 113 is located on the side of the first end face 112 close to the lithium battery cavity, the first end face 112 and the second end face are both circular, the diameter of the second end face 113 is smaller than the diameter of the first end face 112, and the side wall of the sealing cover 120 abuts against the hole wall of the first injection hole section 2 of the injection hole 1 to seal the injection hole 1.

[0039] The side wall of the sealing cover 120 abuts against the hole wall of the first liquid injection hole section 2 of the injection hole 1, thereby ensuring the sealing reliability of the sealing cover 120 to the first liquid injection hole section 2, and further preventing the gas and electrolyte in the lithium battery cavity from escaping to the outside from the second liquid injection hole section 3 and the first liquid injection hole section 2 in turn.

[0040] In this embodiment, if Figure 5 As shown, the sealing member further includes a sealing nail 60 extending along the extension direction of the injection hole 1, and the sealing nail 60 is used to be inserted into the second injection hole segment 3 to seal the second injection hole segment 3, and the axial length of the sealing nail 60 is less than or equal to the axial length of the second injection hole segment 3. The second injection hole segment 3 is sealed by the sealing nail 60 to prevent the gas and electrolyte in the lithium battery cavity from escaping into the first injection hole segment 2, wherein the axial length of the sealing nail 60 is less than or equal to the axial length of the second injection hole segment 3, which can ensure that the sealing nail 60 is completely inserted into the second injection hole segment 3, further ensuring the sealing effect of the sealing nail.

[0041] Specifically, the sealing nail is made of plastic material. The sealing nail 60 includes a sealing nail end 61 and a sealing nail pin 62 which are connected in sequence. The sealing nail pin 62 can be a pyramid, a cone, or a cylinder with a diameter slightly smaller than that of the sealing nail end 61 .

[0042] In this embodiment, if Figure 1 As shown, the seal is integrally formed by injection molding. Such a setting can reduce the processing difficulty and production cost of the seal, wherein the seal is made of plastic material.

[0043] The utility model also provides a lithium battery cover structure, such as Figure 1 As shown, the lithium battery cover structure includes the sealing member in the above embodiment, and the substrate 70 includes two end surfaces arranged opposite to each other along a first preset direction. The injection hole 1 extends along the first preset direction and passes through the two end surfaces. The sealing member is used to seal the injection hole 1. The first preset direction is Figure 2 The vertical direction shown in .

[0044] The lithium battery cover plate structure of the utility model includes the sealing member, the substrate 70, the two pole ears 80 and the stop frame 90 in the above-mentioned embodiment. The stop frame 90 is arranged on the end face of the substrate 70 close to the lithium battery cavity, and is used for axially limiting the electrode in the lithium battery cavity. The injection hole 1 passes through the substrate 70 and the stop frame 90 to communicate with the lithium battery cavity. The sealing member is used to seal the injection hole 1. The sealing member includes a sealing body 11. The sealing body 11 has a sealing portion 111 for sealing in the injection hole 1. The sealing portion 111 is provided with a pressure relief recess 12. The pressure relief recess 12 is recessed along the extension direction of the injection hole 1. The setting of the pressure relief recess 12 reduces The thickness of the sealing portion 111 at the position with the pressure relief recess 12 is increased, so that when the pressure value of the gas in the lithium battery cavity exceeds the threshold, the gas in the lithium battery cavity passes through the position with the pressure relief recess 12 of the sealing portion 111 under the action of air pressure to relieve the pressure of the lithium battery cavity and prevent the lithium battery from exploding. Therefore, the injection hole 1 can be used as an explosion-proof hole, so that there is no need to open an explosion-proof hole on the lithium battery cover structure to relieve the pressure of the lithium battery, thereby solving the problems of complex structure and high production cost of the lithium battery cover in the prior art, simplifying the structure of the lithium battery cover, and reducing the production cost of the lithium battery cover and the lithium battery.

[0045] Specifically, the base plate 70, the two tabs 80 and the stop frame 90 are integrally formed by injection molding. Such a configuration can reduce the processing difficulty and production cost of the lithium battery cover structure.

[0046] The utility model also provides a lithium battery, including the lithium battery cover plate structure and battery module in the above-mentioned embodiment, the substrate 70 is covered on the battery module and surrounds the battery module to form a lithium battery cavity, and the injection hole 1 is connected to the lithium battery cavity. The lithium battery cover plate structure includes the seal in the above-mentioned embodiment, the substrate 70, two pole ears 80 and the stop frame 90, the stop frame 90 is arranged on the end face of the substrate 70 close to the lithium battery cavity, and is used for axially limiting the electrode in the lithium battery cavity, the injection hole 1 passes through the substrate 70 and the stop frame 90 to be connected with the lithium battery cavity, the seal is used to seal the injection hole 1, the seal includes a sealing body 11, the sealing body 11 has a sealing portion 111 for sealing in the injection hole 1, and a pressure relief recess 12 is arranged on the sealing portion 111, and the pressure relief recess 12 is recessed along the extension direction of the injection hole 1, and the provision of the pressure relief recess 12 reduces the sealing. The thickness of the portion 111 at the position with the pressure relief recess 12 makes it easy for the gas in the lithium battery cavity to penetrate the position with the pressure relief recess 12 of the sealing portion 111 under the action of air pressure when the pressure value of the gas in the lithium battery cavity exceeds a threshold value, so as to relieve the pressure of the lithium battery cavity and prevent the lithium battery from exploding. Therefore, the injection hole 1 can be used as an explosion-proof hole, so that there is no need to open an explosion-proof hole on the lithium battery cover plate structure to relieve the pressure of the lithium battery, thereby solving the problems of complex structure and high production cost of the lithium battery cover plate in the prior art, simplifying the structure of the lithium battery cover plate, and reducing the production cost of the lithium battery cover plate and the lithium battery.

[0047] From the above description, it can be seen that the above embodiments of the utility model achieve the following technical effects:

[0048] The sealing member of the utility model comprises a sealing body 11, which has a sealing portion 111 for sealing in the liquid injection hole 1, and a pressure relief recess 12 is arranged on the sealing portion 111, and the pressure relief recess 12 is recessed along the extension direction of the liquid injection hole 1. The arrangement of the pressure relief recess 12 reduces the thickness of the sealing portion 111 at the position having the pressure relief recess 12, so that when the pressure value of the gas in the lithium battery cavity exceeds the threshold value, the gas in the lithium battery cavity passes through the position having the pressure relief recess 12 of the sealing portion 111 under the action of the air pressure, so as to relieve the pressure of the lithium battery cavity and prevent the lithium battery from exploding. Therefore, the liquid injection hole 1 can be used as an explosion-proof hole, so that there is no need to open an explosion-proof hole on the lithium battery cover plate structure to relieve the pressure of the lithium battery, thereby solving the problems of complex structure and high production cost of the lithium battery cover plate in the prior art, simplifying the structure of the lithium battery cover plate, and reducing the production cost of the lithium battery cover plate and the lithium battery.

[0049] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0050] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0051] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sealing member for sealing a liquid injection hole (1) of a lithium battery cover structure, wherein the lithium battery cover structure is covered on a battery module and surrounds the battery module to form a lithium battery cavity, wherein the liquid injection hole (1) is connected to the lithium battery cavity, and wherein: The sealing member comprises: A sealing body (11), the sealing body (11) having a sealing portion (111) for sealing in the liquid injection hole (1); The sealing portion (111) is provided with a pressure relief recess (12), and the pressure relief recess (12) is recessed along the extension direction of the injection hole (1), so that when the pressure value of the gas in the lithium battery cavity exceeds a threshold value, the gas in the lithium battery cavity passes through the position of the sealing portion (111) having the pressure relief recess (12) under the action of the gas pressure, so as to relieve the pressure of the lithium battery cavity.

2. The seal according to claim 1, characterized in that The sealing portion (111) comprises a sealing cover (120), wherein the sealing cover (120) has a first end face (112) and a second end face (113) which are arranged opposite to each other along the extension direction of the liquid injection hole (1), and a groove (114) is provided on the first end face (112) or the second end face (113), and the groove (114) is recessed toward the inner side of the sealing cover (120) along the extension direction of the liquid injection hole (1) to form the pressure relief recess (12).

3. The seal according to claim 2, characterized in that The first end surface (112) and the second end surface (113) are both provided with a plurality of grooves (114), and the plurality of grooves (114) on the first end surface (112) and the plurality of grooves (114) on the second end surface (113) are arranged in a one-to-one correspondence with each other.

4. The seal according to claim 2, characterized in that The groove (114) is an annular groove; and / or the groove (114) is a polygonal groove.

5. The seal according to claim 2, characterized in that The depth of the groove (114) along the extension direction of the liquid injection hole (1) is d, and the depth of the sealing cover (120) along the extension direction of the liquid injection hole (1) is S, wherein 1 / 8S≤d≤1 / 3S.

6. The seal according to claim 1, characterized in that The injection hole (1) comprises a first injection hole section (2) and a second injection hole section (3) which are interconnected, the first injection hole section (2) being located on a side of the second injection hole section (3) away from the lithium battery cavity, the first injection hole section (2) and the second injection hole section (3) being both cylindrical holes, the flow cross section of the first injection hole section (2) being larger than the flow cross section of the second injection hole section (3), the axis of the first injection hole section (2) being arranged to coincide with the axis of the second injection hole section (3), and the sealing portion (111) being used to seal in the first injection hole section (2).

7. The seal according to claim 2, characterized in that The second end face (113) is located on a side of the first end face (112) close to the lithium battery cavity, the first end face (112) and the second end face are both circular, the diameter of the second end face (113) is smaller than the diameter of the first end face (112), and the side wall of the sealing cover (120) abuts against the hole wall of the first liquid injection hole section (2) of the liquid injection hole (1) to seal the liquid injection hole (1).

8. The seal according to claim 6, characterized in that The sealing member is integrally formed by injection molding.

9. A lithium battery cover structure, characterized in that: Comprising the sealing member described in any one of claims 1 to 8, the lithium battery cover structure further comprising a substrate (70), the substrate (70) comprising two end faces arranged opposite to each other along a first preset direction, the injection hole (1) extending along the first preset direction and passing through the two end faces, and the sealing member being used to seal the injection hole (1).

10. A lithium battery, characterized in that: It comprises the lithium battery cover plate structure and battery module of claim 9, wherein the substrate (70) is covered on the battery module and surrounds the battery module to form a lithium battery cavity, and the injection hole (1) is connected to the lithium battery cavity.

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