A floating liquid injection cup sealing structure and a liquid injection device using the sealing structure

Abstract

The present invention discloses a floating liquid filling cup sealing structure and a liquid filling device using the sealing structure, including a sealing component, a slide, a vertical plate and a driving unit, the sealing component includes a sliding arm and a sealing head, the sealing head is upwardly connected to the sliding arm, the slide includes a first slide groove, the vertical plate includes a second slide groove, the end of the sliding arm passes through the first slide groove and the second slide groove, the first slide groove and the second slide groove are designed so that when the driving unit drives the slide relative to the vertical plate, the sliding arm can drive the sealing head to slide horizontally to move away from the liquid filling port, or slide up and down to open or seal the liquid filling port. The liquid filling device includes a sealing structure, a shut-off valve and a cup body, and the shut-off valve and the air path pipeline connected to the second inner cavity include a length section that is horizontally inclined downward, so that the electrolyte entering the length section flows back to the second inner cavity under the action of its own weight. The present invention has a reasonable structure, good sealing effect, good adaptability and is conducive to improving the service life of the sealing head.

Description

Technical Field

[0001] The invention relates to the technical field of lithium battery production, in particular to a floating liquid filling cup sealing structure and a liquid filling device using the sealing structure. Background Art

[0002] Lithium battery filling is a key step in the production process of lithium batteries for new energy vehicles. It involves accurately and evenly injecting electrolyte into the assembled but unsealed battery housing. This process is critical to ensuring battery performance, safety and life. The entire filling process must be carried out under a strictly controlled environment, usually in a constant temperature and humidity, dust-free workshop to avoid contamination by impurities. The filling port needs to be sealed before and after the filling process. The existing sealing structure is often simple in structure, with multiple sealing heads directly mounted on a fixed plate and moving synchronously, such as Figure 1 As shown, the fixed plate moves up and down to achieve sealing or open the injection port. Since the fixed plate is subjected to force at multiple dispersed positions and is easily deformed, when the fixed plate is deformed or the sealing head is worn, problems such as unreliable sealing or excessive compression and permanent deformation of the sealing head may occur, which is not conducive to improving the injection quality. In addition, the existing sealing structure often occupies a large operating space, resulting in a relatively high overall height of the equipment. Summary of the invention

[0003] The present invention discloses a floating liquid filling cup sealing structure, which solves the technical problems of unreliable sealing of the liquid filling port and short service life of the sealing head in the prior art, and has the technical effects of reasonable structure, good sealing effect, good adaptability, being conducive to improving the service life of the sealing head and saving operating space. The technical scheme adopted is as follows:

[0004] A floating liquid filling cup sealing structure includes a sealing component, a slide, a vertical plate and a driving unit. The sealing component includes a sliding arm and a sealing head. The sealing head is upwardly connected to the sliding arm. The slide includes a first slide groove, and the vertical plate includes a second slide groove. The end of the sliding arm passes through the first slide groove and the second slide groove. The first slide groove and the second slide groove are designed so that when the driving unit drives the slide to slide relative to the vertical plate, the sliding arm can drive the sealing head to slide horizontally to move away from the liquid filling port, or slide up and down to open or seal the liquid filling port.

[0005] On the basis of the above technical solution, the vertical plates are arranged on both sides of the slide and are fixedly arranged, the slide includes a plurality of independent concave cavities, and the sealing components are multiple and arranged in the concave cavities in a one-to-one correspondence.

[0006] On the basis of the above technical solution, it also includes a fixedly arranged pressing sleeve, which can abut against the slide table downward to prevent the slide table from jumping up and down.

[0007] Based on the above technical solution, the second slide groove includes a horizontal section and a vertical section with a smooth transition, the first slide groove includes an inclined section, the length section of the sliding arm extending into the first slide groove, and / or the length section of the sliding arm extending into the second slide groove has a polygonal cross-section.

[0008] On the basis of the above technical solution, a wear-resistant sleeve made of polymer material is embedded in the vertical plate, and the wear-resistant sleeve forms the inner wall surface of the second sliding groove.

[0009] Based on the above technical solution, the sealing head includes a pressure rod, a sealing bracket and a sealing rubber. The pressure rod is fixedly connected to the sliding arm upward and connected to the sealing bracket downward. The sealing rubber sleeve is arranged on the sealing bracket to seal the liquid injection port.

[0010] On the basis of the above technical solution, the pressure rod is connected downwardly to the sealing bracket by point contact, line contact or ball head pair, so that the sealing bracket can be automatically aligned.

[0011] Based on the above technical solution, the sealing bracket includes a first inner cavity, the lower end of the pressure rod extends into the first inner cavity and includes an end protrusion, the end surface of the end protrusion downwardly abutting against the flat inner bottom surface of the first inner cavity is a spherical surface, and when the spherical surface contacts the flat inner bottom surface of the first inner cavity, the end protrusion is spaced apart from the inner top surface of the first inner cavity.

[0012] On the basis of the above technical solution, the sealing rubber is annularly sleeved outside the sealing bracket, and the end surface of the sealing rubber in contact with the sealing bracket is stepped, and the sealing rubber can contact the liquid injection port to seal the liquid injection port.

[0013] A liquid injection device comprises a sealing structure, a shut-off valve and a cup body as described above, wherein the cup body comprises a second inner cavity connected to the liquid injection port, and the second inner cavity is also connected to the battery inner cavity, the sealing structure is used to seal or open the liquid injection port to facilitate liquid injection by the injection needle, the second inner cavity is connected to an external pressure source through the shut-off valve to form positive pressure or negative pressure in the second inner cavity, and the air path pipeline connecting the shut-off valve and the second inner cavity comprises a length section inclined horizontally downward, so that the electrolyte entering the length section can flow back to the second inner cavity under the action of its own weight.

[0014] Beneficial Effects

[0015] The present invention has a reasonable structure. The up and down displacement of the sealing component is achieved by the horizontal sliding of the slide table, which can reduce the deformation of the slide table due to uneven force, thereby causing the seal to be unreliable or the sealing head to be compressed excessively. In addition, the setting of the compression sleeve in the present application can prevent the slide table from jumping up and down and provide a downward force. On the one hand, this can reduce the probability of deformation of the slide table, which is beneficial to improving the sealing quality. On the other hand, it can make the sealing component press the injection port downward; furthermore, the two vertical plates are arranged on both sides of the slide table, which can limit the slide table to swing left and right, which is beneficial to ensure the displacement accuracy of the slide table, thereby improving the displacement accuracy of the sealing component. In addition, multiple sealing components are respectively arranged in independent concave cavities, which can reduce the interference between two adjacent injection processes. The setting of the concave cavity can also reduce the friction between the slide table and the end face of the injection port, which is beneficial to increase the service life and improve the accuracy of the kinematic pair.

[0016] In the present invention, the up and down displacement of the sealing assembly is achieved by horizontal sliding of the slide table, which can also reduce the operating space of the sealing structure, which is beneficial to reducing the overall height of the equipment and saving space.

[0017] In the present invention, the sliding arm extends into the first slide groove and the second slide groove, and the first slide groove and the second slide groove are designed so that the driving unit drives the slide table to slide relative to the vertical plate to achieve horizontal displacement and vertical displacement of the sealing component. The structure is exquisite, the driving structure is simplified, and it is beneficial to reduce the failure rate of the sealing structure and ensure stable and continuous production. In addition, the first slide groove includes a horizontal section and a vertical section, and the cross-section of the length section of the sliding arm extending into the second slide groove is a polygon, such as a quadrilateral, so that the sealing component can be ensured to have a good vertical state and avoid the sealing component from flipping during the sliding process.

[0018] In the present invention, the pressure rod is connected downwardly with the sealing bracket in point contact, line contact or ball joint. In this way, when the pressure rod deviates from the axis of the injection port due to installation problems, or the center of mass of the sealing rubber changes due to wear, the sealing head can automatically align to have good sealing contact with the injection port, thereby increasing the service life of the sealing head and improving the sealing quality. In addition, the sealing rubber is annularly sleeved outside the sealing bracket, which can reduce the amount of sealing rubber used and help reduce the cost of use.

[0019] In the liquid injection device of the present invention, the gas path pipeline connecting the shut-off valve and the second inner cavity includes a length section that is horizontally inclined downward. In this way, when positive pressure / negative pressure is formed in the second inner cavity, it can prevent the electrolyte mist in the inner cavity from being adsorbed and liquefied and crystallized in the pipeline, thereby blocking the pipeline or damaging devices connected to the pipeline, such as a vacuum gauge. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0021] Figure 1 : Sealing structure in the prior art;

[0022] Figure 2 : A schematic diagram of the three-dimensional structure of the present invention;

[0023] Figure 3 : A schematic diagram of the structure of the top view of the present invention;

[0024] Figure 4 : A schematic diagram of the three-dimensional structure of the sealing component in the present invention;

[0025] Figure 5 : Schematic diagram of the cross-sectional structure of the side view of the sealing component;

[0026] Figure 6 : Schematic diagram of the structure of the movable arm cooperating with the two vertical plates;

[0027] Figure 7 : Schematic diagram of the structure of the slide and the two vertical plates;

[0028] Figure 8 : A schematic diagram of the structure of the gas pipeline in which the shut-off valve is connected to the second inner cavity;

[0029] Fig. 9 : Schematic diagram of the injection process of the injection device; DETAILED DESCRIPTION

[0030] The following description and accompanying drawings fully illustrate the specific embodiments of this article so that those skilled in the art can practice them. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments of this article includes the entire scope of the claims, as well as all available equivalents of the claims. Herein, the terms "first", "second", etc. are only used to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the structure, device or equipment including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to such structure, device or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the structure, device or equipment including the elements. Each embodiment is described in a progressive manner herein, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other.

[0031] The terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. in this document indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this document and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of this document, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, it can also be the internal communication of two elements, it can be a direct connection, or it can be an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] As used herein, the term "plurality" means two or more than two, unless otherwise specified.

[0033] In this document, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0034] In this article, the term "and / or" is a description of the association relationship between objects, indicating that three relationships may exist. For example, A and / or B means: A or B, or, A and B.

[0035] like Figures 2 to 7The floating liquid filling cup sealing structure shown in FIG. 1 includes a sealing component 1, a slide 2, a vertical plate 3 and a driving unit. Figure 1 The sealing structure shown is arranged above the cup body 100 , and a plurality of liquid injection ports 101 are arranged on the top surface of the cup body 100 .

[0036] like Figure 6 and 7 As shown, there are two upright plates 3 and they are arranged on both sides of the slide 2 and fixedly arranged. In this embodiment, the sealing mechanism is arranged on the cup body 100, and the cup body 100 has a second cavity 102, and the second cavity 102 is connected to the liquid injection port 101 formed on the cup body 100. The two upright plates 3 are fixedly arranged on the cup body 100, and the slide 2 is clearance-matched with the two upright plates 100, as shown in FIG. Figure 7 As shown, the slide table 2 is provided with a plurality of independent concave cavities 22 , and the sealing components 1 are provided in a plurality and one-to-one correspondence in the concave cavities 22 .

[0037] like Figure 6 and 7 As shown, it also includes a pressing sleeve 4 fixed on the vertical plate 3, and the pressing sleeve 4 can be downwardly passed through the wear-resistant block to abut against the slide 2 to prevent the slide 2 from jumping up and down. Specifically, a groove is provided on the end surface of the pressing sleeve 4 facing the slide 2, and a polymer wear-resistant material, such as a polymer wear-resistant material made of PEEK, is embedded in the groove. The polymer wear-resistant material extends out of the groove and can abut against the top surface of the slide 2. In the absence of external force, there is a gap between the top surface of the slide 2 and the bottom surface of the wear-resistant material, which allows the slide 2 to slide smoothly. Among them, the PEEK material is a prior art and will not be repeated here.

[0038] like Figure 4 and 5 As shown, the sealing assembly 1 includes a sliding arm 11 and a sealing head. The sealing head is upwardly connected to the sliding arm 11. As shown in the figure, the sliding arm 11 includes two arms extending horizontally outward.

[0039] Two first slide grooves 21 are provided on the slide table 2 at positions corresponding to the positions of the slide arms 11, and second slide grooves 31 are provided at corresponding positions of the two vertical plates 3. The ends of the two arms of the slide arm 11 pass through the first slide groove 21 and the second slide groove 31 in sequence. In this embodiment, the second slide groove 31 includes a horizontal section and a vertical section with a smooth transition. Specifically, a concave cavity is provided on the outer side of the vertical plate 3, and a wear-resistant sleeve 32 of a polymer material is embedded in the concave cavity, such as a wear-resistant sleeve 32 made of PEEK material, and the wear-resistant sleeve 32 forms the inner wall of the second slide groove 31; Figure 7 As shown, the first slide groove 21 includes an inclined section.

[0040] The first slide groove 21 and the second slide groove 31 are designed to cooperate with each other. When the driving unit drives the slide table 2 to slide relative to the vertical plate 3 and the sliding arm 11 is in the vertical section of the second slide groove 31, the sliding arm 11 drives the sealing head to slide upward to open or seal the injection port 101; when the driving unit drives the slide table 2 to slide relative to the vertical plate 3 and the sliding arm 11 is in the horizontal section of the second slide groove 31, the sliding arm 11 drives the sealing head to slide horizontally away from the injection port 101, thereby facilitating the injection of the injection needle.

[0041] like Figure 6 As shown, the cross section of the length section of the sliding arm 11 extending into the second slide groove 31 is a polygon. In this embodiment, the polygon is a regular quadrilateral, and the adjacent sides are smoothly transitioned; the cross section of the length section of the sliding arm 11 extending into the first slide groove 21 is a circle. In this way, the sealing component 1 can always be in a good vertical state, and the sealing component 1 can be prevented from flipping due to a fault during the sliding of the slide 2, which can lead to the situation that the sealing component 1 cannot be sealed. In other embodiments of the present invention, the cross section of at least one of the two length sections of the sliding arm 11 extending into the first slide groove 21 and the second slide groove 31 is a polygon, such as the cross section of the length section of the sliding arm 11 extending into the second slide groove 31 is a circle and the cross section of the length section extending into the first slide groove 21 is a polygon. In addition, in this embodiment, the sliding arm 11 and the first slide groove 21 and the second slide groove 31 are respectively clearance-matched, which is conducive to the smooth sliding of the sliding arm 11 therein.

[0042] like Figure 4 and 5 As shown, the sealing head includes a pressure rod 12, a sealing bracket 13 and a sealing rubber 14. The pressure rod 12 is fixedly connected to the sliding arm 11 upwardly, and the pressure rod 12 is connected to the sealing bracket 13 downwardly and transmits force by point contact. Specifically, the sealing bracket 13 includes a first inner cavity 16, and the lower end of the pressure rod 12 extends into the first inner cavity 16 and includes a terminal convex portion. The end surface of the terminal convex portion downwardly abutting against the flat inner bottom surface of the first inner cavity 16 is a spherical surface. In addition, it also includes two pairs of open rings 15, which are connected to the first inner cavity 16 upwardly. The inner top surface of the cavity 16 is fixedly connected and enclosed to form a through hole, and the pressure rod 12 passes through the through hole and cooperates with the clearance of the through hole, which is convenient for assembly and helps to reduce the thickness of the sealing bracket 13, saving the action space of the sealing head, and when the bottom spherical surface of the terminal protrusion contacts the flat inner bottom surface of the first inner cavity 16, the terminal protrusion and the inner top surface of the first inner cavity 16 are spaced apart, so that during the upward movement of the pressure rod 12, the sealing bracket 13 can be automatically aligned so that it is in line with the axis of the injection port 101 to achieve a good seal. In other embodiments of the present invention, the pressure rod 12 can also transmit force in a contact manner with the sealing bracket 13 ball head pair, that is, the bottom end surface of the terminal protrusion is a spherical surface, and the inner bottom surface of the first inner cavity 16 facing the spherical surface is a spherical surface, so that the sealing bracket 13 can also be automatically aligned.

[0043] like Figure 4As shown, the sealing rubber 14 is annularly sleeved outside the sealing bracket 13, and the end surface of the sealing rubber 14 contacting the sealing bracket 13 is stepped, which can ensure a firm connection and prevent falling off, and can also save the amount of sealing rubber 14. The sealing rubber 14 can contact the injection port 101 to seal the injection port.

[0044] A liquid injection device includes a sealing structure, a shut-off valve and a cup body 100 as described above, wherein the cup body includes a second inner cavity 102 connected to a liquid injection port 101, the second inner cavity 102 is downwardly connected to a battery inner cavity through a pipeline, and a valve is provided on the pipeline connected to the battery inner cavity with the second inner cavity 102. Figure 8 As shown, the second inner cavity 102 can be connected to an external pressure source through a shut-off valve to form positive pressure or negative pressure in the second inner cavity 102. When positive pressure / negative pressure is reciprocally formed in the second inner cavity 102, the electrolyte in the cup body 100 can be injected into the battery and the gas in the battery can be fully discharged.

[0045] In order to prevent the electrolyte mist from being adsorbed and liquefied, crystallized and aggregated in the pipeline during the formation of positive pressure / negative pressure, the gas pipeline connecting the shut-off valve and the second inner cavity 102 includes a horizontal downward inclined length section 200. In this embodiment, the lower end of the length section 200 is downwardly connected to the vertical pipe section 300, and the end of the vertical pipe section 300 is connected to the second inner cavity 102. In this way, the electrolyte entering the inclined length section 200 can quickly flow back to the inner cavity under the action of its own weight.

[0046] In addition, in the prior art, in order to more accurately reflect the air pressure in the second inner cavity 102, it is usually necessary to set the pipe section connected to the vacuum gauge 400 as close to the second inner cavity 102 as possible. In the present application, the pipe section connected to the vacuum gauge 400 is arranged on the inclined length section 200 and close to the vertical pipe section 300. On the one hand, it is beneficial to more accurately reflect the air pressure in the second inner cavity 102 and improve the detection accuracy. On the other hand, the flow rate of the electrolyte mist entering the inclined length section 200 is slowed down, and after liquefaction, it will flow back to the second inner cavity 102. This can greatly reduce the amount of electrolyte mist reaching the vacuum gauge 400, which is beneficial to increase the service life of the vacuum gauge 400.

[0047] Working process

[0048] Take a liquid injection process as an example

[0049] First, the shut-off valve closes the connection with the second inner cavity 102, the sealing assembly 1 is in the initial position, and the sealing head presses the injection port 101 downward;

[0050] Afterwards, the slide table 2 slides in the first direction under the action of the driving unit, driving the sliding arm 11 to slide upward in the vertical section of the second slide groove 31 and abut against the inner top surface of the second slide groove 31, thereby opening the liquid injection port;

[0051] Then the slide table 2 continues to slide in the first direction, driving the slide arm 11 to slide horizontally in the second slide groove 31 to avoid the liquid injection port 101;

[0052] Then, the injection needle is inserted into the injection port 101 to inject liquid into the second inner cavity 102;

[0053] Then, the slide table 2 slides in a second direction opposite to the first direction under the action of the driving unit, driving the slide arm 11 to slide horizontally in the second slide groove 31 to above the liquid injection port 101;

[0054] After that, the slide table 2 continues to slide along the second direction, and under the action of the first slide groove 21, the slide arm 11 is driven to slide downward in the vertical section of the second slide groove 31 and seal the liquid injection port 101;

[0055] After that, the shut-off valve is opened, and a positive pressure is first formed in the second inner cavity 102 under the action of the external pressure source, so that part of the electrolyte enters the battery inner cavity under the action of the pressure difference. Then, a negative pressure is formed in the second inner cavity 102 under the action of the external pressure source, so that the gas in the battery inner cavity is discharged outward, and then a positive pressure is formed in the second inner cavity 102 again, and this cycle is repeated until the electrolyte completes entering the battery inner cavity from the second inner cavity 102;

[0056] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments, and any changes or modifications made based on the present invention belong to the scope of protection claimed by the present invention.

Claims

1. A floating liquid filling cup sealing structure, characterized in that: The invention comprises a sealing assembly (1), a slide (2), a vertical plate (3) and a driving unit, wherein the sealing assembly (1) comprises a sliding arm (11) and a sealing head, wherein the sealing head is upwardly connected to the sliding arm (11), the slide (2) comprises a first sliding groove (21), the vertical plate (3) comprises a second sliding groove (31), the end of the sliding arm (11) passes through the first sliding groove (21) and the second sliding groove (31), the second sliding groove (31) comprises a horizontal section and a vertical section with a smooth transition, and the first sliding groove (21) comprises an inclined section; The first slide groove (21) and the second slide groove (31) are designed such that when the driving unit drives the slide table (2) to slide relative to the vertical plate (3) and the sliding arm (11) is in the vertical section of the second slide groove (31), the sliding arm (11) drives the sealing head to slide upward to open or seal the injection port (101); when the driving unit drives the slide table (2) to slide relative to the vertical plate (3) and the sliding arm (11) is in the horizontal section of the second slide groove (31), the sliding arm (11) drives the sealing head to slide horizontally to move away from the injection port (101), thereby facilitating injection of liquid by the injection needle; The sealing head comprises a pressure rod (12), a sealing bracket (13) and a sealing rubber (14); the pressure rod (12) is fixedly connected to the sliding arm (11) upwards, the pressure rod (12) is connected to the sealing bracket (13) downwards, and the sealing rubber (14) is sleeved on the sealing bracket (13) for sealing the liquid injection port (101); The pressure rod (12) is connected downwardly to the sealing bracket (13) in a point contact connection or a ball head connection, so that the sealing bracket (13) can be automatically aligned.

2. The floating liquid filling cup sealing structure according to claim 1, characterized in that: The vertical plates (3) are arranged on both sides of the slide (2) and are fixedly disposed. The slide (2) comprises a plurality of independent concave cavities (22). The sealing components (1) are arranged in a plurality of concave cavities (22) in a one-to-one correspondence.

3. The floating liquid filling cup sealing structure according to claim 2, characterized in that: It also comprises a fixedly arranged pressing sleeve (4), wherein the pressing sleeve (4) can abut against the slide table (2) downwards to prevent the slide table (2) from bouncing up and down.

4. The floating liquid filling cup sealing structure according to claim 1, characterized in that: The length section of the sliding arm (11) extending into the first sliding groove (21), and / or the length section of the sliding arm extending into the second sliding groove (31) is polygonal in cross section.

5. The floating liquid filling cup sealing structure according to claim 4, characterized in that: A wear-resistant sleeve (32) is embedded in the vertical plate (3), and the wear-resistant sleeve (32) forms the inner wall surface of the second sliding groove (31).

6. The floating liquid filling cup sealing structure according to any one of claims 1 to 5, characterized in that: The sealing bracket (13) includes a first inner cavity (16), the lower end of the pressure rod (12) extends into the first inner cavity (16) and includes an end convex portion, the end surface of the end convex portion that abuts against the flat inner bottom surface of the first inner cavity (16) downward is a spherical surface, and when the spherical surface contacts the flat inner bottom surface of the first inner cavity (16), the end convex portion is spaced apart from the inner top surface of the first inner cavity (16).

7. The floating liquid filling cup sealing structure according to claim 6, characterized in that: The sealing rubber (14) is annularly sleeved outside the sealing bracket (13), and the end surface of the sealing rubber (14) in contact with the sealing bracket (13) is stepped. The sealing rubber (14) can contact the liquid injection port to seal the liquid injection port (101).

8. A liquid injection device, comprising a sealing structure, a shut-off valve and a cup body (100) as claimed in any one of claims 1 to 5 and 7, wherein the cup body (100) comprises a second inner cavity (102) connected to the liquid injection port (101), and the second inner cavity (102) is also connected to the battery inner cavity, the sealing structure is used to seal or open the liquid injection port (101) to facilitate liquid injection by the liquid injection needle, and the second inner cavity (102) is connected to an external pressure source through the shut-off valve to form positive pressure or negative pressure in the second inner cavity (102), characterized in that: The gas path pipeline connecting the shutoff valve and the second inner cavity (102) comprises a length section (200) that is horizontally inclined downward, so that the electrolyte that enters the length section (200) flows back to the second inner cavity (102) under the action of its own weight.

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