Liquid injection device

Abstract

The utility model relates to the technical field of battery processing, and discloses a liquid injection device which comprises a bearing main body and a limiting main body, the bearing main body is provided with a containing cavity with an opening and used for containing a battery shell, and a guide part is arranged on the edge of at least part of the opening of the containing cavity and used for guiding the battery shell to be placed or taken out; a protruding part is arranged on the limiting body, and the protruding part and the guiding part are arranged in a matched mode. In the liquid injection process, the limiting main body and the bearing main body are relatively fixed, and the gap between the guide part and the battery shell is filled by the convex part, so that the expansion of the battery shell caused by the positive pressure effect in the liquid injection process is effectively prevented, the dimensional accuracy and the structural integrity of the battery shell are guaranteed, and the service life of the battery shell is prolonged. And improvement of battery performance and quality is facilitated.

Description

Technical Field

[0001] The present application relates to the field of battery processing technology, and further to a liquid injection device. Background Art

[0002] At present, in the existing battery manufacturing process, the injection device is a key tool to realize the injection of electrolyte into the battery. The traditional injection tooling usually adopts an integrated structure design, which is characterized by simple structure and intuitive operation. However, this design has some limitations.

[0003] Specifically, the traditional tooling is designed with a similar guide slope above the opening. The original intention of this design is to facilitate the placement of the battery shell, but it also brings the problem of insufficient support. Since there will be a certain gap between the guide slope and the battery shell, during the injection process, the battery shell is prone to expansion under the positive pressure, especially after multiple cycles of injection. This expansion will not only cause the thickness of the battery cell to exceed the standard, but also affect the production efficiency and product quality of subsequent processes. Utility Model Content

[0004] In view of the above technical problems, the purpose of the present application is to provide a liquid injection device, which aims to avoid the expansion phenomenon that is easily produced in the battery shell during the traditional battery injection process, thereby improving the quality of battery production.

[0005] In order to achieve the above-mentioned purpose, the present application provides a liquid injection device, comprising: a receiving body and a limiting body, wherein the receiving body has an open accommodating cavity for placing a battery shell, and at least part of the opening edge of the accommodating cavity is provided with a guide portion for guiding the placement or removal of the battery shell;

[0006] The limiting body is provided with a raised portion, which is matched with the guide portion; during the liquid injection process, the limiting body and the receiving body are relatively fixed, and the gap between the guide portion and the battery shell is filled by the raised portion to prevent the battery shell from expanding.

[0007] In some embodiments, the limiting body is further provided with a connecting end surface, the connecting end surface and the protruding portion are arranged adjacent to each other, and the extending height of the protruding portion in the vertical direction exceeds the bottom of the connecting end surface;

[0008] The top wall of the receiving body is adjacent to the guide part. When injecting liquid, the connecting end surface abuts against the top wall of the receiving body, and the protrusion is embedded between the guide part and the battery housing.

[0009] In some embodiments, a corresponding connection structure is provided between the connection end surface of the limiting body and the top wall of the receiving body to achieve relative fixation between the limiting body and the receiving body.

[0010] In some embodiments, the guide portion is disposed circumferentially along the opening edge of the accommodating cavity to form an annular recessed structure;

[0011] The limiting body has an annular contour, and the protrusion is arranged along the annular contour of the limiting body.

[0012] In some embodiments, the limiting body includes two long side limiting portions and two short side limiting portions, the long side limiting portions are respectively arranged corresponding to the two long sides of the battery shell, and the short side limiting portions are respectively arranged corresponding to the two short sides of the battery shell, so as to jointly form an annular contour of the limiting body; wherein each of the long side limiting portions has a long side protrusion, and each of the short side limiting portions has a short side protrusion, and the long side protrusion and the short side protrusion jointly form the protrusion portion.

[0013] In some embodiments, one of the long side limiting portions and one of the short side limiting portions are connected to form an L-shaped limiting structure;

[0014] Or, one of the long side limiting portions and the two short side limiting portions are connected to form a C-shaped limiting structure together;

[0015] Or, one of the short side limiting portions and the two long side limiting portions are connected to form a C-shaped limiting structure together;

[0016] Alternatively, the two long side limiting portions and the two short side limiting portions are independently arranged.

[0017] In some embodiments, each of the long side limiting portions is provided with a first limiting edge, and each of the short side limiting portions is provided with a second limiting edge, and the first limiting edge and the second limiting edge are both inclined. During the injection process, the first limiting edge of the long side limiting portion fits with the second limiting edge of the adjacent short side limiting portion.

[0018] In some embodiments, each of the long side limiting portions has a first connecting end surface, and each of the short side limiting portions has a second connecting end surface, and the first connecting end surface and the second connecting end surface together form the connecting end surface, so that when liquid is injected, the top wall of the receiving body is simultaneously connected and fixed relative to the two first connecting end surfaces and the two second connecting end surfaces.

[0019] In some embodiments, the limiting body also has a resistance end face, and the resistance end face is smoothly connected to the side wall of the protrusion facing away from the connecting end face. When the protrusion is embedded in the guide portion, the resistance end face and the inner wall of the accommodating cavity are flush, so that the battery shell is tightly attached to the resistance end face and the inner wall of the accommodating cavity during the injection process.

[0020] In some embodiments, the guide portion is a chamfered structure, and the protrusion is a triangular protrusion. When injecting liquid, the triangular protrusion fits with the chamfered structure, so that the limiting body and the receiving body together form an integral structure adapted to the outer contour of the battery shell.

[0021] Compared with the prior art, the liquid injection device provided in this application has the following beneficial effects:

[0022] 1. In this application, the gap between the battery housing and the guide portion of the receiving body is filled by the raised portion on the limiting body, which effectively prevents the battery housing from expanding due to positive pressure during the injection process, thereby maintaining the dimensional stability and structural integrity of the battery housing. This design not only enhances the stability of the battery housing during the injection process and reduces the risk of electrolyte leakage, but also improves production efficiency and product quality, ensuring the continuity and reliability of the battery manufacturing process.

[0023] 2. In the present application, the connecting end face on the limiting body and the top wall of the receiving body can be precisely docked during liquid injection, ensuring the stability and safety of the liquid injection device; on the other hand, the abutting end face is smoothly connected to the side wall of the protruding portion, ensuring that when the protruding portion is embedded in the gap between the guide portion and the battery shell, the abutting end face is flush with the inner wall of the accommodating cavity, so that the battery shell can be tightly attached to the abutting end face and the inner wall of the accommodating cavity during the liquid injection process, providing uniform and tight support, thereby effectively preventing any movement or expansion of the battery shell during the liquid injection process.

[0024] 3. In the present application, an annular recessed structure is formed by arranging the guide portion circumferentially along the opening edge of the accommodating cavity. At the same time, the raised portion is arranged along the annular contour of the limiting body, thereby forming a continuous supporting structure. This not only enhances the stability and integrity of the battery casing during the liquid injection process, but also evenly distributes the pressure through the annular contour, effectively avoiding local stress concentration, thereby reducing the risk of deformation of the battery casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present application.

[0026] Figure 1It is a partial cross-sectional view of a battery housing placed in a receiving body in one embodiment of the present application;

[0027] Figure 2 It is a structural diagram of a receiving body in one embodiment of the present application;

[0028] Figure 3 It is a structural schematic diagram of an embodiment of the present application;

[0029] Figure 4 is a cross-sectional view of an embodiment of the present application;

[0030] Figure 5 yes Figure 4 A partial enlarged view of the middle A;

[0031] Figure 6 It is a schematic diagram of the explosion structure of an embodiment of the present application;

[0032] Figure 7 This is a schematic diagram of the structure of the long side limiting portion in one embodiment of the present application;

[0033] Figure 8 It is a schematic structural diagram of a short side limiting portion in an embodiment of the present application.

[0034] Explanation of the accompanying figures: battery case 1; receiving body 2; accommodating cavity 200; guiding part 21; limiting body 3; protruding part 31; abutting end face 32; connecting end face 33; long side limiting part 34; long side protrusion 341; first limiting edge 342; first connecting end face 343; short side limiting part 35; short side protrusion 351; second limiting edge 352; second connecting end face 353; pin 4. DETAILED DESCRIPTION

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the specific implementation methods of the present application will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0036] In order to simplify the drawings, only the parts related to the application are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0037] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0038] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0041] In the field of modern battery manufacturing, the injection process is one of the key steps in the battery production process, which directly affects the performance and safety of the battery. The traditional injection tooling design usually adopts an integrated structure. Although this design can meet basic production needs in the early stage, its limitations are gradually revealed with the development of battery technology and the improvement of product quality requirements.

[0042] Specifically, the chamfer (or similar structure) set above the opening of the traditional tooling provides convenience for the placement of the battery shell, but due to the lack of an effective support structure, the battery shell is prone to expansion during the injection process, especially under positive pressure. This expansion will not only cause the battery shell size to exceed the standard, but may also affect the uniform injection of the electrolyte, thereby affecting the performance and consistency of the battery. In addition, the expansion problem during multiple cycles of injection may also have an adverse effect on subsequent packaging, welding and other processes, increasing production costs and reducing production efficiency.

[0043] To solve these problems, refer to the manual. Figure 3 and Figure 4 The liquid injection device provided in the present application can effectively control the expansion of the battery housing 1 during the liquid injection process, thereby improving the stability of the liquid injection process and the quality of the battery product.

[0044] The present application provides a liquid injection device, including a receiving body 2 and a limiting body 3. Figure 2 The receiving body 2 has an open accommodating cavity 200, and the accommodating cavity 200 can place the battery housing 1 for subsequent liquid injection work.

[0045] Reference Manual Attached Figure 1 and Figure 2 At least part of the opening edge of the accommodating cavity 200 is provided with a guide portion 21, which can facilitate the insertion or removal of the battery housing 1. Figure 5 As shown, a protrusion 31 is provided on the limiting body 3, and the protrusion 31 and the guide part 21 are matched. Specifically, during the liquid injection process, the limiting body 3 and the receiving body 2 are relatively fixed, and the gap between the guide part 21 and the battery housing 1 is filled by the protrusion 31. This close fit effectively prevents the battery housing 1 from expanding due to the positive pressure during the liquid injection process, thereby ensuring the dimensional accuracy and structural integrity of the battery housing 1.

[0046] Through this design, the injection device not only improves the stability of the battery housing 1 during the injection process, but also improves the quality and consistency of the battery product by reducing the expansion and deformation of the battery housing 1. In addition, the cooperation between the protrusion 31 and the guide portion 21 ensures that the position of the battery housing 1 in the accommodating cavity 200 is accurately fixed, reducing the uneven injection of the electrolyte caused by position deviation, and further improving the performance of the battery.

[0047] In this embodiment, there is no specific limitation on the number of accommodating chambers 200 in the receiving body 2. A plurality of independent accommodating chambers 200 can be designed in the receiving body 2, allowing for simultaneous injection of multiple battery shells 1 to improve production efficiency. Each accommodating chamber 200 is provided with a corresponding limiting body 3 to ensure that each battery shell 1 can be properly positioned and supported during the injection process. Furthermore, a shared limiting body 3 can be designed, and through a corresponding mechanical layout, a limiting body 3 can provide support for multiple accommodating chambers 200 at the same time, which can ensure the stability of the battery shell 1 during the injection process and the uniform injection of the electrolyte; or a rotary injection device can be used, so that each accommodating chamber 200 can be moved to the injection position in turn, and positioned and supported by the same limiting body 3, which not only saves space but also improves the use efficiency of the equipment.

[0048] In one embodiment, based on the above embodiment, Figure 5As shown, a connecting end surface 33 is provided on the limiting body 3 , and the connecting end surface 33 is located adjacent to the protruding portion 31 , and the top wall of the receiving body 2 is adjacent to the guiding portion 21 .

[0049] During the injection, the connection end face 33 abuts against the top wall of the receiving body 2 to form a stable support platform, effectively preventing the battery housing 1 from being displaced or tilted during the injection process; at the same time, the protrusion 31 is embedded between the guide portion 21 and the battery housing 1. As shown in the figure, the vertical extension height of the protrusion 31 exceeds the bottom surface of the connection end face 33, ensuring that the protrusion 31 can penetrate into the gap between the guide portion 21 and the battery housing 1 to form a tight fit.

[0050] Furthermore, a corresponding connection structure is provided between the connection end surface 33 and the top wall of the receiving body 2 to achieve relative fixation between the limiting body 3 and the receiving body 2 .

[0051] It can be understood that the provided connection structure not only enhances the overall strength of the liquid injection device, but also ensures the precise alignment and stable fit between the receiving body 2 and the limiting body 3 during the liquid injection process.

[0052] In other words, during the liquid injection operation, the connection end surface 33 of the limiting body 3 and the top wall of the receiving body 2 are seamlessly connected through the connection structure, thereby providing a stable support platform for the battery housing 1. The precise embedding of the protrusion 31 further enhances the stability, ensuring that the battery housing 1 will not be displaced or deformed due to pressure or improper operation during the liquid injection process.

[0053] In some embodiments, the connection structure in the above content may include multiple connecting pieces, and the connecting end surface 33 and the top wall of the receiving body 2 are both provided with multiple corresponding assembly holes, and the corresponding arrangement of these assembly holes provides an accurate positioning basis for installing the connecting pieces. The selected connecting piece may be a pin 4, and this design not only simplifies the assembly process, but also improves the reliability and stability of the connection.

[0054] The use of the pin 4 as a connecting piece enables the operator to quickly complete the connection or separation between the limiting body 3 and the receiving body 2. When the pin 4 passes through the assembly hole, the limiting body 3 is firmly fixed on the receiving body 2, ensuring the precise fit and stability during the injection process. When equipment maintenance or replacement of the battery housing 1 is required, the limiting body 3 and the receiving body 2 can be easily separated by simply pulling out the pin 4, so as to quickly perform the required operation.

[0055] In this embodiment, the advantage of this connection method is its ease of operation. Fixing can be completed by simply inserting the pin 4 into the assembly hole. It is also convenient for disassembly and maintenance. On the other hand, by setting multiple assembly holes and corresponding pins 4 between the limiting body 3 and the receiving body 2, multi-point support is achieved to enhance the stability of the overall structure.

[0056] In one embodiment, the guide portion 21 of the receiving body 2 is designed as a chamfered structure, and the corresponding protrusion 31 on the limiting body 3 is in the shape of a triangular protrusion. During the injection operation, the triangular protrusion fits with the chamfered structure, ensuring the precise positioning and stability of the battery housing 1 during the injection process. This cooperation not only provides uniform support for the battery housing 1, but also effectively prevents deformation caused by uneven pressure or expansion, thereby ensuring that the electrolyte can be evenly injected into the battery housing 1, improving the overall quality of the battery product.

[0057] With this design, during liquid injection, the limiting body 3 and the receiving body 2 together form an integral structure, which is adapted to the outer contour of the battery housing 1 and can reduce the relative collision between the liquid injection device and the battery housing 1 .

[0058] In addition, the adaptability to battery housings 1 of different models can be optimized by adjusting the shape or size of the triangular protrusions, or changing the depth and angle of the chamfered structure.

[0059] Based on the above embodiment, the limiting body 3 is provided with a contact end face 32, which is smoothly connected to the side wall of the protrusion 31 on the side away from the connection end face 33. When the protrusion 31 is embedded in the guide portion 21 of the receiving body 2, the contact end face 32 is kept flush with the inner wall of the accommodating cavity 200, ensuring that the battery housing 1 can be closely attached to the contact end face 32 and the inner wall of the accommodating cavity 200 during the injection process, providing a continuous support surface, and providing uniform contact and stable support for the battery housing 1.

[0060] It can be understood that during the injection process, the battery shell 1 is in close contact with the abutting end face 32 and the inner wall of the accommodating chamber 200. This close contact not only improves the positioning accuracy of the battery shell 1, but also effectively prevents the battery shell 1 from expanding or deforming due to uneven pressure. On the other hand, the close combination of the battery shell 1 with the abutting end face 32 and the inner wall of the accommodating chamber 200 improves the sealing of the entire injection environment, helps to maintain the pressure conditions required during the injection process, and prevents the intrusion of air and other pollutants.

[0061] In another embodiment, based on the above embodiment, the guide portion 21 is arranged circumferentially along the opening edge of the accommodating cavity 200, thereby forming an annular recessed structure. This annular design not only provides uniform support for the stable placement of the battery housing 1, but also ensures that the circumferential direction of the battery housing 1 is evenly distributed during the injection process, thereby effectively preventing the battery housing 1 from being deformed due to excessive local pressure.

[0062] At the same time, the limiting body 3 adopts an annular contour design, and the protrusion 31 is arranged along the annular contour of the limiting body 3. The cooperation between the protrusion 31 and the annular recessed structure realizes the precise positioning and stable support of the battery housing 1 during the liquid injection process.

[0063] It can be understood that this design in the present embodiment not only improves the stability of the battery housing 1 during the injection process, but also promotes the uniform injection of the electrolyte into the battery housing 1 through the uniformly distributed pressure, thereby avoiding the uneven distribution of the electrolyte caused by uneven pressure, thereby improving the performance and life of the battery.

[0064] In addition, the raised portion 31 can be either a continuous integrated annular raised portion or a segmented raised portion, as long as it can correspond to the guide portion 21 of the receiving body 2, thereby enabling the liquid injection device to provide customized support and positioning for battery housings 1 of different sizes while maintaining the stability of the overall structure.

[0065] In one embodiment, Figure 6 As shown, the limiting body 3 includes two long side limiting parts 34 and two short side limiting parts 35, which are respectively arranged corresponding to the long side and the short side of the battery housing 1. This design is based on the geometric characteristics of the cross section of the battery housing 1. Whether it is a rectangle or a square, a plurality of limiting parts corresponding to its side edges can form a circular profile of the limiting body 3, thereby accurately matching the edge of the battery housing 1 and achieving all-round stable support.

[0066] Furthermore, when the cross section of the battery housing 1 is square, the long side limiter 34 and the short side limiter 35 can have the same size. This uniform size setting simplifies the production and maintenance process because the same components can be used to fit all edges, reducing production costs and improving the versatility of components. In the case of a rectangular cross section, by adjusting the size of the long side limiter 34 and the short side limiter 35, the specific aspect ratio of the battery housing 1 can be accurately adapted, further optimizing the injection process.

[0067] Based on the above, if Figure 7 and Figure 8As shown, each long side limiting portion 34 and short side limiting portion 35 is respectively provided with a corresponding long side protrusion 341 and short side protrusion 351, which work together to form the protrusion 31 mentioned above, ensuring that the protrusion 31 can be tightly embedded between the guide portion 21 of the receiving body 2 and the battery housing 1 in both the long side and short side directions, thereby effectively filling the gap and improving the positioning accuracy of the battery housing 1 and the stability during liquid injection.

[0068] It can be understood that the cooperation of the long side protrusions 341 and the short side protrusions 351 not only prevents the battery housing 1 from expanding and displacing during the injection process, but also helps the battery housing 1 to more evenly withstand the pressure generated during the injection process through their support for the long side and short side of the battery housing 1. This uniform support helps to avoid excessive local force and reduce the deformation or damage that may occur to the battery housing 1 during the injection process.

[0069] Furthermore, through different combinations of the long side limiter 34 and the short side limiter 35, a variety of limiter structures are formed. The first form is that each long side limiter 34 is connected to a short side limiter 35 to form an L-shaped structure. When the liquid is injected, two L-shaped structures can be used. At the same time, during production, a long side limiter 34 and a short side limiter 35 are integrally formed or pre-fixed and installed to improve the subsequent operation efficiency. The second form is that a long side limiter 34 is connected to two short side limiters 35 to form a C-shaped structure centered on the long side. Of course, it can also be a short side limiter 35 connected to two long side limiters 34 to form a C-shaped structure centered on the short side. In this case, a C-shaped structure and an independent (long side / short side) limiter can be used. In the third form, all the long side limiters 34 and the short side limiters 35 are independently set, which is easier to understand. When operating, the four limiters can be installed to the corresponding positions respectively.

[0070] In one embodiment, each long side limiting portion 34 is provided with a first limiting edge 342, and each short side limiting portion 35 is provided with a second limiting edge 352, and these edges are inclined to achieve a tighter and more stable fit. In the working state, the first limiting edge 342 of the long side limiting portion 34 and the second limiting edge 352 of the adjacent short side limiting portion 35 fit each other, so that the multiple limiting portions form a continuous support surface.

[0071] Based on the above content, this embodiment optimizes the stability of the injection device during injection by increasing the contact area and adjusting the contact angle, while effectively dispersing the local stress generated by the injection pressure; on the other hand, the inclined edge serves as a guide surface to assist the long side limit portion 34 and the short side limit portion 35 to quickly align with the corresponding guide portion 21, thereby simplifying the assembly process and improving operating efficiency.

[0072] Furthermore, each long side limiting portion 34 has a first connecting end face 343, and each short side limiting portion 35 has a second connecting end face 353. The connecting end face 33 mentioned above is formed by all the first connecting end faces 343 and the second connecting end faces 353 in this embodiment, ensuring that the top wall of the receiving body 2 can be relatively connected and fixed to the two first connecting end faces 343 and the two second connecting end faces 353 at the same time, providing a balanced and comprehensive supporting structure for the battery housing 1, and significantly improving the overall stability and support efficiency by evenly distributing the force exerted on the battery housing 1 during the injection process.

[0073] At the same time, the pin connection method in the above embodiment can also be applied to the present embodiment. All the first connection end faces 343 and the second connection end faces 353 are opposite to the top wall of the receiving body 2 during liquid injection, and a stable connection and fixation are achieved through the pin 4. Moreover, the pin 4 can form multiple support points on each limiting portion, thereby achieving a multi-point support effect, improving the reliability and safety of the liquid injection device, and ensuring the fixing effect of the battery housing 1.

[0074] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. A liquid injection device, characterized in that: include: A receiving body, wherein the receiving body has an open accommodating cavity for accommodating a battery housing, and at least part of the opening edge of the accommodating cavity is provided with a guide portion for guiding the placement or removal of the battery housing; A limiting body is provided with a raised portion, and the raised portion is matched with the guide portion; during the liquid injection process, the limiting body and the receiving body are relatively fixed, and the gap between the guide portion and the battery shell is filled by the raised portion to prevent the battery shell from expanding.

2. The liquid injection device according to claim 1, characterized in that: The limiting body is further provided with a connecting end surface, the connecting end surface and the protruding portion are arranged adjacent to each other, and the extending height of the protruding portion in the vertical direction exceeds the bottom of the connecting end surface; The top wall of the receiving body is adjacent to the guide part. When injecting liquid, the connecting end surface abuts against the top wall of the receiving body, and the protrusion is embedded between the guide part and the battery housing.

3. The liquid injection device according to claim 2, characterized in that: A corresponding connection structure is provided between the connection end surface of the limiting body and the top wall of the receiving body to achieve relative fixation between the limiting body and the receiving body.

4. The liquid injection device according to claim 2, characterized in that: The guide portion is arranged along the circumferential direction of the opening edge of the accommodating cavity to form an annular recessed structure; The limiting body has an annular contour, and the protrusion is arranged along the annular contour of the limiting body.

5. The liquid injection device according to claim 4, characterized in that: The limiting body includes two long side limiting parts and two short side limiting parts, wherein the long side limiting parts are respectively arranged corresponding to the two long sides of the battery housing, and the short side limiting parts are respectively arranged corresponding to the two short sides of the battery housing, so as to jointly form an annular contour of the limiting body; Wherein, each of the long-side limiting portions has a long-side protrusion, each of the short-side limiting portions has a short-side protrusion, and the long-side protrusion and the short-side protrusion together form the protrusion portion.

6. The liquid injection device according to claim 5, characterized in that: One of the long side limiting portions and one of the short side limiting portions are connected to form an L-shaped limiting structure; or, One of the long side limiting portions and the two short side limiting portions are connected to form a C-shaped limiting structure; or, One of the short side limiting portions and the two long side limiting portions are connected to form a C-shaped limiting structure; or, The two long side limiting portions and the two short side limiting portions are independently arranged.

7. The liquid injection device according to claim 6, characterized in that: Each of the long side limiting portions is provided with a first limiting edge, and each of the short side limiting portions is provided with a second limiting edge. The first limiting edge and the second limiting edge are both inclined. During the injection process, the first limiting edge of the long side limiting portion fits with the second limiting edge of the adjacent short side limiting portion.

8. The liquid injection device according to claim 5, characterized in that: Each of the long side limiting portions has a first connecting end face, and each of the short side limiting portions has a second connecting end face, and the first connecting end face and the second connecting end face together form the connecting end face, so that when liquid is injected, the top wall of the receiving body is simultaneously connected and fixed relative to the two first connecting end faces and the two second connecting end faces.

9. The liquid injection device according to any one of claims 2 to 8, characterized in that: The limiting body also has a contact end face, and the contact end face is smoothly connected to the side wall of the protrusion facing away from the connecting end face. When the protrusion is embedded in the guide part, the contact end face and the inner wall of the accommodating cavity are flush, so that the battery shell is in close contact with the contact end face and the inner wall of the accommodating cavity during the liquid injection process.

10. The liquid injection device according to claim 9, characterized in that: The guide portion is a chamfered structure, and the protrusion is a triangular protrusion. When injecting liquid, the triangular protrusion fits with the chamfered structure, so that the limiting body and the receiving body together form an integral structure adapted to the outer contour of the battery housing.

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