Sealing structure and battery

Abstract

The application relates to the technical field of power batteries, and provides a sealing structure and a battery. The sealing structure disclosed by the application comprises an inner liquid injection hole and an outer liquid injection hole which are connected in communication, the aperture of the inner liquid injection hole is smaller than that of the outer liquid injection hole, the sealing structure comprises a sealing plug capable of sealing the inner liquid injection hole and a sealing cover capable of sealing the outer liquid injection hole, the sealing cover comprises a sealing cover main body and a first protruding part arranged on one side of the sealing cover main body, the part close to the edge of the sealing cover main body protrudes to the side provided with the first protruding part and forms an annular groove, the outer peripheral wall of the sealing cover main body is welded to the side wall of the outer liquid injection hole, and the first protruding part can limit the movement of the sealing plug along the inner liquid injection hole in the axial direction to the side of the first protruding part. The sealing structure disclosed by the application is beneficial to improving the welding quality of the sealing cover and the sealing effect of the sealing structure, so that the safety risk caused by the sealing failure of the liquid injection hole can be prevented.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to a sealed structure. This application also relates to a battery using this sealed structure. Background Technology

[0002] A battery is an energy storage device composed of multiple battery cells connected in series and parallel, and integrated with key components such as a battery management system and a thermal management system.

[0003] During battery production, electrolyte injection holes need to be reserved on the battery. After the electrode assembly is assembled into the battery casing, electrolyte needs to be injected into the battery casing through the injection holes, and then the injection holes are sealed by a sealing structure.

[0004] Due to structural design limitations, existing batteries suffer from poor sealing of the electrolyte filling hole. If the filling hole is not properly sealed, electrolyte leakage may lead to risks such as battery explosion, affecting the safety of battery use. Utility Model Content

[0005] In view of this, the present application aims to provide a sealing structure to improve sealing performance.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows: A sealing structure for sealing a liquid injection hole in a battery casing, the liquid injection hole including an inner liquid injection hole and an outer liquid injection hole that are connected to each other, wherein the diameter of the inner liquid injection hole is smaller than the diameter of the outer liquid injection hole. The sealing structure includes a sealing plug capable of sealing the inner injection hole and a sealing cap capable of sealing the outer injection hole. The sealing cap includes a sealing cap body and a first protrusion on one side of the sealing cap body; the portion of the sealing cap body near the edge protrudes toward the side where the first protrusion is provided, forming an annular groove; the outer peripheral wall of the sealing cap body is welded to the side wall of the outer injection hole, and the first protrusion can restrict the sealing plug from moving axially toward the first protrusion along the inner injection hole.

[0007] Furthermore, the sidewall of the outer injection hole is frustum-shaped, and the outer peripheral wall of the sealing cap body includes a first outer peripheral wall and a second outer peripheral wall connected together. Along the axial direction of the outer injection hole, the second outer peripheral wall is located away from the inner injection hole relative to the first outer peripheral wall, and the first outer peripheral wall is frustum-shaped and the second outer peripheral wall is cylindrical. The sealing cap body is welded to the side wall of the outer injection hole via the second outer peripheral wall.

[0008] Furthermore, the sealing plug includes a sealing plug body capable of sealing the inner injection hole, and a guide portion disposed on one side of the sealing plug body; With the guide portion inserted into the inner injection hole, a channel is formed between the guide portion and the side wall of the inner injection hole, and the channel connects the outer injection hole and the inner space of the top cover body.

[0009] Furthermore, the sealing plug includes a sealing plug body capable of sealing the inner injection hole, and an extension extending radially outward from the sealing plug body along the inner injection hole; With the sealing plug body sealing the inner injection hole, the extension overlaps the bottom wall of the outer injection hole.

[0010] Furthermore, the outer periphery of the sealing plug body is provided with a plurality of protrusions, which are arranged sequentially at intervals along the axial direction of the inner injection hole, and each of the protrusions surrounds the outer periphery of the sealing plug body.

[0011] Furthermore, the sealing plug body is frustum-shaped, or the sealing plug body is cylindrical.

[0012] Furthermore, the inner injection hole includes a first injection hole and a second injection hole connected in sequence, with the first injection hole located on the side closer to the inner space of the battery casing relative to the second injection hole; The radial dimension of the first injection hole is larger than that of the second injection hole, and the sealing plug body includes a first sealing body that seals the first injection hole and a second sealing body that seals the second injection hole.

[0013] Furthermore, the sealing plug is made of an elastic material; The sealing cap is made of metal.

[0014] Compared with related technologies, this application has the following advantages: (1) The sealing structure described in this application, by setting a groove, can better absorb the stress generated during the welding process of the sealing cover and the top cover body in the battery casing, which is conducive to improving the welding quality of the sealing cover and the yield rate of the welding operation. The first protrusion can prevent the sealing plug from moving axially along the injection hole, which can ensure the sealing performance of the sealing plug. Both of these structures are conducive to improving the sealing effect of the sealing structure, thereby better preventing the safety risks caused by the sealing failure at the injection hole and improving the safety of battery application.

[0015] (2) The first outer peripheral wall and the second outer peripheral wall are set to different shapes. The first outer peripheral wall is convenient to fit with the side wall of the outer injection hole, while the second outer peripheral wall fits with the side wall of the outer injection hole, which facilitates the improvement of welding quality and thus improves the success rate of welding sealing.

[0016] (3) The guide part is provided to facilitate the assembly process of the sealing plug. The guide part is used for pre-installation, while the sealing plug body is used for final installation. A channel is formed between the guide part and the side wall of the inner injection hole, through which helium can be injected into the battery casing, which facilitates subsequent helium testing.

[0017] (4) By providing an extension on the main body of the sealing plug, when the sealing plug is installed in the ideal installation position, the extension overlaps the bottom wall of the outer injection hole, which can better restrict the installation position of the sealing plug and prevent the risk of the sealing plug being driven into the space inside the battery casing.

[0018] (5) By setting multiple protrusions on the outer periphery of the sealing plug body, the multiple protrusions are arranged sequentially at intervals along the axial direction of the inner injection hole, and each protrusion surrounds the outer periphery of the sealing plug body, which can improve the sealing quality of the sealing plug to the inner injection hole and reduce the risk of leakage at the injection hole.

[0019] (6) The sealing plug body is set as a frustum shape, which makes the sealing plug body insertion process smoother and helps to ensure the sealing quality. The sealing plug body is designed as a cylinder, which can match the injection hole and better ensure the sealing quality.

[0020] (7) The inner injection hole is designed as a first injection hole and a second injection hole with different diameters. At the same time, the sealing plug body includes a first sealing body and a second sealing body. After the sealing plug is installed in place, the connecting part of the first injection hole and the second injection hole forms a step. This step can effectively block the first sealing body, making it difficult for the first sealing body to fall out of the inner injection hole, thereby helping to ensure the sealing effect of the sealing plug on the inner injection hole.

[0021] (8) The sealing plug is made of elastic material, which can ensure the sealing effect of the inner injection hole through its own deformation, and at the same time ensure that the sealing plug can be smoothly inserted into the inner injection hole to form the first seal. The sealing cover is made of metal material and can be welded to the existing top cover body to form the second seal. The two sealing structures work together to better ensure the sealing quality of the sealing structure.

[0022] Another object of this application is to provide a battery in which the liquid injection hole is sealed by the sealing structure described above.

[0023] Furthermore, a groove is provided on the lower plastic of the battery casing, the groove is located below the liquid injection hole, and the bottom wall of the groove is stepped; The bottom wall of the tank, in the portion not directly opposite the injection hole, is covered with multiple through holes, and part of the bottom wall of the tank can press against the electrode assembly inside the battery casing.

[0024] The battery described in this application, by applying the above-mentioned sealing structure, can improve the sealing quality of the injection hole and better prevent the safety risks caused by the failure of the injection hole seal. The bottom wall of the tank is set in a stepped shape, which helps to improve the injection efficiency. Part of the bottom wall of the tank is pressed against the electrode assembly, which can better prevent the electrode assembly from shaking. At the same time, through reasonable structural arrangement, the parts that are not pressed against the electrode assembly can also avoid the tabs, thereby facilitating the arrangement of the tabs. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is an exemplary exploded view of the sealing structure described in this application applied to a battery; Figure 2 for Figure 1 Top view; Figure 3 For along Figure 2 An exemplary cross-sectional view of line AA in the middle; Figure 4 for Figure 3 Enlarged view of part B; Figure 5 This is an exemplary structural diagram of the sealing cap described in an embodiment of this application; Figure 6 for Figure 5 An exemplary structural diagram from another perspective; Figure 7 for Figure 5 Another exemplary structural diagram from a different perspective; Figure 8 This is an exemplary structural diagram of the sealing plug described in an embodiment of this application; Figure 9 For along Figure 2 Another exemplary cross-sectional view of line AA in the middle; Figure 10 for Figure 9 Enlarged view of part C; Figure 11 This is another exemplary structural diagram of the sealing plug described in the embodiments of this application; Figure 12 This is an exploded view of the housing top cover described in the embodiment of this application; Figure 13 for Figure 12 The top view of the housing cover shown; Figure 14 For along Figure 13 An exemplary cross-sectional view of the DD line; Figure 15 This is a cross-sectional view of another type of sealing plug described in the embodiments of this application, in its application state; Figure 16 This is another exemplary structural diagram of the sealing plug described in the embodiments of this application; Figure 17 This is a cross-sectional view of a sealing plug in a pre-installed state according to an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures: 1. Top cover body; 101. Injection hole; 1011. Inner injection hole; 10111. First injection hole; 10112. Second injection hole; 1012. Outer injection hole; 2. Sealing cap; 201. Sealing cap body; 2011. Groove; 2012. First outer peripheral wall; 2013. Second outer peripheral wall; 202. First protrusion; 3. Sealing plug; 301. Sealing plug body; 3011. Protrusion; 3012. First sealing body; 3013. Second sealing body; 302. Guide portion; 303. Extension portion; 304. Second protrusion portion; 4. Lower plastic; 401. Tank body; 4011. First bottom wall; 4012. Second bottom wall; 401a. Through hole; 5. Pole group; e. Side wall; f. Passage; a. Inner space of the top cover body. Detailed Implementation

[0027] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0029] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0031] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0033] An embodiment of the first aspect of this application provides a sealing structure for sealing a liquid injection hole in a battery casing. This sealing structure, by adjusting its own structure and its engagement with the top cover body in the battery casing, can improve the sealing quality of the liquid injection hole, thereby enhancing the safety and reliability of battery applications.

[0034] In related technologies, batteries serve as core energy storage devices in fields such as new energy vehicles and energy storage systems. Their structure and manufacturing processes directly affect overall performance and safety. A battery is composed of multiple individual battery cells connected in a carefully designed series-parallel configuration. This configuration meets specific voltage and capacity requirements while achieving efficient energy storage and release. Furthermore, batteries integrate key components such as a battery management system (BMS) and a thermal management system.

[0035] During battery manufacturing, an electrolyte injection hole needs to be pre-drilled in the battery casing. After the electrode assembly is assembled into the battery casing, electrolyte needs to be injected into the casing through this injection hole. The electrolyte is the medium for ion transport inside the battery and plays a crucial role in battery performance. After the electrolyte injection is completed, the injection hole needs to be strictly sealed using a sealing structure to ensure that the electrolyte does not leak.

[0036] However, existing batteries often suffer from poor sealing of the electrolyte filling port due to limitations in their structural design. Once the seal of the filling port is flawed, electrolyte can slowly leak out through the gaps. Electrolytes are typically corrosive and flammable; once leaked, they not only corrode other components inside the battery pack but also reduce the battery pack's performance and lifespan. More seriously, under certain conditions, leaked electrolyte can trigger a short circuit inside the battery pack, generating a large amount of heat and gas, ultimately leading to extreme and dangerous situations such as battery pack explosion.

[0037] For example, existing sealing structures generally include a sealing cap and a sealing plug, with the sealing plug located inside the sealing cap, that is, on the side closest to the internal space of the battery casing. During actual battery operation, a corresponding air pressure is generated inside the battery casing, which can reach up to about 0.3 MPa in actual tests. This internal pressure can move the sealing plug upwards, thereby reducing the sealing effect of the sealing plug.

[0038] In addition, in existing battery designs, to improve the sealing effect of the sealing plug on the injection hole, the common technical approach is to increase the outer diameter of the sealing plug to achieve a tight fit between the sealing plug and the inner injection hole. This increases the interference between the two and improves the sealing effect. However, as the outer diameter of the sealing plug increases, there is a problem that the sealing plug pressing equipment has difficulty in driving the sealing plug with a larger outer diameter into the injection hole.

[0039] In view of this, in order to overcome the shortcomings of related technologies, the sealing structure of this embodiment combines... Figures 1 to 3 As shown, in terms of overall design, this sealing structure is used to seal the liquid injection hole 101 of the battery casing, and the sealing structure mainly includes a sealing cap 2 and a sealing plug 3.

[0040] Reference Figure 4 As shown, in a specific implementation, the injection hole 101 includes an inner injection hole 1011 and an outer injection hole 1012 that are connected to each other. The diameter of the inner injection hole 1011 is smaller than the diameter of the outer injection hole 1012. The sealing plug 3 can seal the inner injection hole 1011, while the sealing cap 2 can seal the outer injection hole 1012.

[0041] To better understand the sealing structure of this embodiment, a brief description of the battery structure is provided first. The battery mentioned in this embodiment refers to a conventional battery cell or battery unit. The battery mainly includes a battery casing and electrode groups 5 disposed within the battery casing. The battery casing mainly includes a casing body and a top cover, which enclose a space to accommodate the electrode groups 5. The top cover mainly includes a top cover body 1 and a lower plastic insert 4 disposed on the top cover body 1 facing the internal space of the battery casing. The structures of the top cover body 1 and the lower plastic insert 4 can both refer to the structures in the prior art.

[0042] It should be noted that in this embodiment, the liquid injection hole 101 is formed on the top cover body 1, and the inner liquid injection hole 1011 is arranged on the side closer to the inner space of the battery casing, while the outer liquid injection hole 1012 is arranged on the side away from the inner space of the battery casing relative to the inner liquid injection hole 1011.

[0043] Reference Figure 4 As shown, the sealing cap 2 includes a sealing cap body 201 and a first protrusion 202 located on one side of the sealing cap body 201. Specifically, the portion of the sealing cap body 201 near its edge protrudes toward the side where the first protrusion 202 is located, forming an annular groove 2011. The outer peripheral wall of the sealing cap body 201 is welded to the side wall of the outer injection hole 1012, and the first protrusion 202 can restrict the sealing plug 3 from moving axially toward the first protrusion 202 along the inner injection hole 1011.

[0044] In a preferred embodiment, the sealing cap body 201 and the first protrusion 202 are an integral structure, which can be manufactured using different forming processes such as stamping and machining.

[0045] The sealing structure of this application, through the groove 2011, can better absorb the stress generated during the welding process of the sealing cap 2, which is conducive to improving the welding quality of the sealing cap 2. The first protrusion 202 can prevent the sealing plug 3 from moving axially along the injection hole 101, which can ensure the sealing performance of the sealing plug 3. Both of these structures are conducive to improving the sealing effect of the sealing structure, thereby better preventing the safety risks caused by the sealing failure at the injection hole 101.

[0046] like Figure 4 As shown, in a preferred example, the diameter of the inner injection hole 1011 is between 0.4 mm and 1.5 mm, and the outer diameter of the first protrusion 202 is smaller than the diameter of the inner injection hole 1011. For example, the diameter of the inner injection hole 1011 is 1.5 mm, and the outer diameter of the first protrusion 202 is 1 mm; the diameter of the inner injection hole 1011 is 1 mm, and the outer diameter of the first protrusion 202 is 0.8 mm; the diameter of the inner injection hole 1011 is 0.5 mm, and the outer diameter of the first protrusion 202 is 0.4 mm, etc.

[0047] In the axial direction of the inner injection hole 1011, the height of the first protrusion 202 is between 0.3mm and 2mm, such as 0.3mm, 0.8mm, 1.2mm, 1.7mm, 2mm, etc.

[0048] Reference Figures 5 to 7 As shown, the shape of the first protrusion 202 can be designed in various shapes, for example... Figure 6 The cross shape shown Figure 7 The shape can be circular, or it can be square, rhomboid, triangular, etc. In a preferred embodiment, the first protrusion 202 is located in the outer injection hole 202, that is, the first protrusion 202 is not inserted into the inner injection hole 1011. In this way, the sealing space of the sealing plug 3 to the inner injection hole 1011 is not occupied, and the sealing effect of the sealing plug 3 to the inner injection hole 1011 can be guaranteed.

[0049] Continue to refer to Figure 3 and Figure 4 As shown, in order to improve the welding yield, in some exemplary embodiments, the sidewall of the outer injection hole 1012 is frustoconical, and the outer peripheral wall of the sealing cap body 201 includes a first outer peripheral wall 2012 and a second outer peripheral wall 2013 connected together. Along the axial direction of the outer injection hole 1012, the second outer peripheral wall 2013 is located at a position away from the inner injection hole 1011 relative to the first outer peripheral wall 2012, and the first outer peripheral wall 2012 is frustoconical, while the second outer peripheral wall 2013 is cylindrical. The sealing cap body 201 is welded to the sidewall of the outer injection hole 1012 through the second outer peripheral wall 2013.

[0050] In the above implementation, the first outer peripheral wall 2012 and the second outer peripheral wall 2013 are set to different shapes. The first outer peripheral wall 2012 is convenient to fit with the side wall of the outer injection hole 1012, while the second outer peripheral wall 2013 fits with the side wall of the outer injection hole 1012, which facilitates the improvement of welding quality and thus improves the success rate of welding sealing.

[0051] In a preferred embodiment, the inclination angle of the first outer peripheral wall 2012 is greater than the inclination angle of the side wall of the outer injection hole 1012, so that during the welding process of the sealing cap 2, the sealing cap 2 can be stably locked in the outer injection hole 1012 by deformation of the edge portion, preventing the sealing cap 2 from shaking during the welding process of the sealing cap 2 and the top cover body 1, thereby improving the welding yield.

[0052] Reference Figure 8 and Figure 17As shown, in some exemplary embodiments, the sealing plug 3 includes a sealing plug body 301 capable of sealing the inner injection hole 1011, and a guide portion 302 disposed on one side of the sealing plug body 301. With the guide portion 302 inserted into the inner injection hole 1011, a channel f is formed between the guide portion 302 and the side wall e of the inner injection hole 1011, and the channel f connects the outer injection hole 1012 and the inner space a of the top cover body.

[0053] It should be noted that in this embodiment, the inner space 'a' of the top cover body refers to the space on the side of the top cover body 1 facing the inside of the battery casing, such as... Figure 17 As shown, the inner space a of the top cover body is formed by the lower plastic 4 and the top cover body 1. The inner space a of the top cover body is connected to the inner space of the battery casing, so that the electrolyte can enter the inner space a of the top cover body through the injection hole 101 and then flow into the inner space of the battery casing.

[0054] In some examples, for example Figure 8 The structure of the sealing plug 3 shown has a guide portion 302 with a roughly triangular cross-sectional shape. That is, the cross-sectional shape of the guide portion 302 can be triangular or nearly triangular. Other cross-sectional shapes are also possible. The outer diameter of the guide portion 302 is the same as the outer diameter of the sealing plug body 301. This shape of the guide portion 302 makes it easier to deform compared to the sealing plug body 301.

[0055] In this embodiment, the guide part 302 facilitates the smooth assembly of the sealing plug 3. Specifically, the guide part 302 is used for pre-installation, while the sealing plug body 301 is used for final installation. That is, the process of inserting the sealing plug body 301 into the inner injection hole 1011 includes two steps: pre-installation and final installation. In the above embodiment, a channel f is formed between the guide part 302 and the side wall e of the inner injection hole 1011, allowing helium to be injected into the inner space a of the top cover body, i.e., into the battery casing, facilitating subsequent helium testing. Figures 9 to 11 As shown, in some exemplary embodiments, the sealing plug 3 includes a sealing plug body 301 capable of sealing the inner injection hole 1011, and an extension 303 extending radially outward from the sealing plug body 301 along the inner injection hole 1011.

[0056] With the sealing plug body 301 sealing the inner injection hole 1011, the extension 303 overlaps the bottom wall of the outer injection hole 1012. In a preferred embodiment, both the inner injection hole 1011 and the outer injection hole 1012 have circular cross-sectional shapes, and both the extension 303 and the sealing plug body 301 have circular cross-sectional shapes. It should be noted that with this type of sealing plug 3, the battery casing does not need to be filled with helium, and the helium detection method can refer to other existing methods.

[0057] It should be understood that the shape of the extension 303 can also be other shapes. For example, there can be multiple extensions 303, which are arranged circumferentially around the sealing plug body 301. Each extension 303 can be, for example, circular, square, triangular, etc.

[0058] In the above implementation, by providing an extension 303 on the sealing plug body 301, when the sealing plug 3 is installed in the ideal installation position, the extension 303 overlaps the bottom wall of the outer injection hole 1012, which can better restrict the installation position of the sealing plug 3 and prevent the risk of the sealing plug 3 being driven into the space inside the battery casing.

[0059] In some exemplary embodiments, the outer periphery of the sealing plug body 301 is provided with a plurality of protrusions 3011, the plurality of protrusions 3011 being arranged sequentially at intervals along the axial direction of the inner injection hole 1011, and each protrusion 3011 surrounding the outer periphery of the sealing plug body.

[0060] In a preferred example, along the axial direction of the inner injection hole 1011, the distance between adjacent protrusions 3011 is between 0.05mm and 0.2mm, such as 0.05mm, 0.08mm, 0.12mm, 0.17mm, 0.2mm, etc.

[0061] It should be noted that, as Figure 10 and Figure 11 As shown, the longitudinal cross-section of protrusion 3011 is close to rectangular. However, other shapes are also possible, such as triangles or semicircles. It should be noted that when the longitudinal cross-section of protrusion 3011 is triangular, the diameter of protrusion 3011 gradually increases from one end into the inner injection hole 1011 to the other end, to facilitate smooth insertion of protrusion 3011 into the inner injection hole 1011.

[0062] In the above implementation, by providing multiple protrusions 3011 on the outer periphery of the sealing plug body 301, and arranging the multiple protrusions 3011 sequentially at intervals along the axial direction of the inner injection hole 1011, and with each protrusion 3011 surrounding the outer periphery of the sealing plug body, the sealing quality of the sealing plug 3 to the inner injection hole 1011 can be improved, and the risk of leakage at the injection hole 101 can be reduced.

[0063] In some of the exemplary embodiments, the sealing plug body 301 is frustum-shaped, or the sealing plug body 301 is cylindrical.

[0064] In one example, the sealing plug body 301 is frustum-shaped, such as... Figure 10 As shown, from one end of the sealing plug body 301 closest to the inner space of the battery body to the other end, the diameter of the sealing plug body 301 gradually decreases, and the included angle between the outer peripheral wall of the sealing plug body 301 and the axial center line of the sealing plug body 301 is between 5° and 15°, such as 5°, 8°, 12°, 15°, etc.

[0065] It should be noted that regardless of whether the shape of the sealing plug body 301 is frustum or cylindrical, by reasonably designing the outer diameter of the sealing plug body 301 and the shape and size of the protrusion 3011, the sealing plug body 301 can ensure a good seal of the inner injection hole 1011.

[0066] In the above implementation, the sealing plug body 301 is set as a frustum shape, which makes the insertion process of the sealing plug body 301 smoother and helps to ensure the sealing quality. The sealing plug body 301 is cylindrical, which can match the injection hole 101 to better ensure the sealing quality.

[0067] like Figure 15 and Figure 16 As shown, in some exemplary embodiments, the inner injection hole 1011 includes a first injection hole 10111 and a second injection hole 10112 connected in sequence, with the first injection hole 10111 located on the side closer to the inner space of the battery casing relative to the second injection hole 10112.

[0068] The radial dimension of the first injection hole 10111 is larger than the radial dimension of the second injection hole 10112. The sealing plug body 301 includes a first sealing body 3012 that seals the first injection hole 10111 and a second sealing body 3013 that seals the second injection hole 10112. The first sealing body 3012 is interference-fitted into the first injection hole 10111, and the second sealing body 3013 is interference-fitted into the second injection hole 10112.

[0069] In a preferred embodiment, the first sealing body 3012 is shaped like a frustum, and the outer diameter of the end of the first sealing body 3012 that is first inserted into the inner injection hole 1011 is smaller, so that the sealing plug 3 can be smoothly inserted into the injection hole 101 by the sealing plug 3 pressing equipment.

[0070] In one example, in order to facilitate the sealing plug 3 pressing device to smoothly insert the sealing plug 3 into the injection hole 101, a chamfer or rounded corner is provided at one end of the first sealing body 3012 that is inserted into the inner injection hole 1011, which can further ensure that the sealing plug 3 is smoothly inserted into the injection hole 101.

[0071] The inner injection hole 1011 is designed as a first injection hole 10111 and a second injection hole 10112 with different diameters. At the same time, the sealing plug body 301 includes a first sealing body 3012 and a second sealing body 3013. After the sealing plug 3 is installed in place, the connecting part of the first injection hole 10111 and the second injection hole 10112 forms a step. This step can effectively block the first sealing body 3012, making it difficult for the first sealing body 3012 to fall out of the inner injection hole 1011. This helps to ensure the sealing effect of the sealing plug 3 on the inner injection hole 101.

[0072] In some of the exemplary embodiments, the sealing plug 3 is made of an elastic material and the sealing cap 2 is made of a metal material.

[0073] In a preferred embodiment, the sealing plug 3 can be made of a compressible elastic material such as fluororubber. The sealing cap 2 is generally made of the same material as the top cover body 1, such as aluminum or steel, to facilitate welding the sealing cap 2 to the top cover body 1.

[0074] The sealing plug 3 is made of elastic material, which can ensure the sealing effect of the inner injection hole 1011 through its own deformation. At the same time, it can ensure that the sealing plug 3 can be smoothly inserted into the inner injection hole 1011 to form the first seal. The sealing cover 2 is made of metal material and can be welded to the existing top cover body 1 to form the second seal. The two sealing structures work together to ensure the sealing quality of the sealing structure.

[0075] like Figure 10 As shown, in some exemplary embodiments, the end of the sealing plug body 301 that is first inserted into the injection hole 101 is provided with a second protrusion 304. The second protrusion 304 protrudes from the sealing plug body 301 along the insertion direction of the sealing plug body 301 and is used to press against the lower plastic 4.

[0076] The second protrusion 304 can be one or multiple protrusions arranged at intervals. The cross-sectional shape of the second protrusion 304 can be, for example, circular, triangular, square, etc. Here, by providing the second protrusion 304 on the sealing plug body 301, the second protrusion 304 can press against the lower plastic 4, which can also limit the insertion position of the sealing plug body 301, thereby improving the installation accuracy of the sealing plug body 301. At the same time, it also helps the operator to judge whether the sealing plug 3 is properly installed in the injection hole 101.

[0077] An embodiment of the second aspect of this application relates to a battery in which the liquid injection port 101 is sealed by the sealing structure described above.

[0078] The battery of this application, by applying the above-mentioned sealing structure, can improve the sealing quality of the injection hole 101, and can better prevent the safety risks caused by the sealing failure of the injection hole 101.

[0079] In related technologies, the electrolyte filling process for batteries typically involves a large volume of electrolyte and often employs a multi-stage filling process. Simultaneously, it's necessary to reduce the filling pressure to prevent electrolyte from overflowing from the filling hole 101 onto the top cover surface. After filling, the battery interior needs to be evacuated, and then the filling hole 101 is sealed using the sealing plug 3 and the sealing cap 2.

[0080] In the existing battery structure, during the process of vacuuming the inside of the battery, the tabs in the battery are affected by negative pressure, which may cause the tabs to block the through hole 401a on the lower plastic 4 that is opposite to the liquid injection hole 101, thus affecting the vacuuming efficiency and effectiveness.

[0081] To solve these problems, such as Figures 12 to 14 As shown, in some exemplary embodiments, a groove 401 is provided on the lower plastic 4 of the battery casing, the groove 401 is located below the injection hole 101, and the bottom wall of the groove 401 is stepped.

[0082] The bottom wall of the tank 401, in areas not directly opposite the electrolyte injection hole 101, is covered with multiple through holes 401a, and a portion of the bottom wall of the tank 401 can press against the electrode assembly 5 inside the battery casing. It should be noted that by placing the through holes 401a in areas not directly opposite the electrolyte injection hole 101, during the electrolyte filling process, the electrolyte entering through the injection hole 101 will flow onto the bottom wall of the tank 401, rather than directly onto the electrode assembly 5, thus preventing damage to the electrode assembly 5 from impacts during electrolyte filling.

[0083] In this embodiment, the bottom wall of the tank 401 is stepped, which helps to improve the injection efficiency. Part of the bottom wall of the tank 401 is pressed against the electrode assembly 5, which can better prevent the electrode assembly 5 from shaking. At the same time, through reasonable structural arrangement, the parts that are not pressed against the electrode assembly 5 can also avoid the electrode tabs, thus facilitating the arrangement of the electrode tabs.

[0084] For ease of description, we will still refer to Figures 12 to 14 As shown, the bottom walls are referred to here as the first bottom wall 4011 and the second bottom wall 4012. It should be noted that in this type of battery pack, the liquid injection hole 101 is arranged at one end of the top cover along its length, and the tank 401 is arranged at one end of the lower plastic 4 along its length.

[0085] In a specific implementation, the first bottom wall 4011 is arranged at the end of the second bottom wall 4012 near the lower plastic 4, and the first bottom wall 4011 is located directly below the injection hole 101. Multiple through holes 401a are provided on the part of the first bottom wall 4011 that is not directly opposite the injection hole 101 and on the second bottom wall 4012.

[0086] In this embodiment, the through hole 401a is illustrated as a circle. It should be understood that the through hole 401a can be other shapes such as square, triangular, elliptical, etc.

[0087] In the above embodiment, the first bottom wall 4011 is arranged relative to the end of the second bottom wall 4012 near the lower plastic 4, and the depth of the groove 401 at the first bottom wall 4011 is greater than the depth of the groove 401 at the second bottom wall 4012. During the electrolyte filling process, the electrolyte can first enter the space of the battery casing through the through hole 401a on the first bottom wall 4011, and then enter the space of the battery casing through the through hole 401a on the second bottom wall 4012.

[0088] In actual installation of the tabs, the space below the second bottom wall 4012 serves as the installation space for the tabs, providing a large installation space for the tabs. At the same time, during the subsequent process of drawing negative pressure from the battery, the deformation of the tabs will not block the through hole 401a on the first bottom wall 4011. The airflow inside the battery can flow out through the through hole 401a on the first bottom wall 4011, ensuring that the process of drawing negative pressure from the battery proceeds smoothly.

[0089] In addition, the first bottom wall 4011 can also be used to press against the electrode group 5 inside the battery casing, which can better prevent the electrode group 5 from shaking along the height direction of the battery (consistent with the axial direction of the through hole 401a), and can ensure the stability of the electrode group 5 installation.

[0090] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A sealing structure for sealing the liquid injection hole of a battery casing, characterized in that: The injection hole includes an inner injection hole and an outer injection hole that are connected to each other, and the diameter of the inner injection hole is smaller than the diameter of the outer injection hole. The sealing structure includes a sealing plug capable of sealing the inner injection hole and a sealing cap capable of sealing the outer injection hole. The sealing cap includes a sealing cap body and a first protrusion on one side of the sealing cap body; the portion of the sealing cap body near the edge protrudes toward the side where the first protrusion is provided, forming an annular groove; the outer peripheral wall of the sealing cap body is welded to the side wall of the outer injection hole, and the first protrusion can restrict the sealing plug from moving axially toward the first protrusion along the inner injection hole.

2. The sealing structure according to claim 1, characterized in that: The sidewall of the outer injection hole is frustum-shaped. The outer peripheral wall of the sealing cap body includes a first outer peripheral wall and a second outer peripheral wall connected together. Along the axial direction of the outer injection hole, the second outer peripheral wall is located away from the inner injection hole relative to the first outer peripheral wall. The first outer peripheral wall is frustum-shaped and the second outer peripheral wall is cylindrical. The sealing cap body is welded to the side wall of the outer injection hole via the second outer peripheral wall.

3. The sealing structure according to claim 1, characterized in that: The sealing plug includes a sealing plug body capable of sealing the inner injection hole, and a guide portion disposed on one side of the sealing plug body; With the guide portion inserted into the inner injection hole, a channel is formed between the guide portion and the side wall of the inner injection hole, and the channel connects the outer injection hole and the inner space of the top cover body.

4. The sealing structure according to claim 1, characterized in that: The sealing plug includes a sealing plug body capable of sealing the inner injection hole, and an extension extending radially outward from the sealing plug body along the inner injection hole; With the sealing plug body sealing the inner injection hole, the extension overlaps the bottom wall of the outer injection hole.

5. The sealing structure according to claim 4, characterized in that: The outer periphery of the sealing plug body is provided with multiple protrusions, which are arranged sequentially at intervals along the axial direction of the inner injection hole, and each protrusion surrounds the outer periphery of the sealing plug body.

6. The sealing structure according to claim 5, characterized in that: The sealing plug body is frustum-shaped, or the sealing plug body is cylindrical.

7. The sealing structure according to claim 4, characterized in that: The inner injection hole includes a first injection hole and a second injection hole connected in sequence, with the first injection hole located on the side closer to the inner space of the battery casing relative to the second injection hole; The radial dimension of the first injection hole is larger than that of the second injection hole, and the sealing plug body includes a first sealing body that seals the first injection hole and a second sealing body that seals the second injection hole.

8. The sealing structure according to any one of claims 1-7, characterized in that: The sealing plug is made of elastic material; The sealing cover is made of metal material.

9. A battery, characterized in that: The liquid injection hole of the battery is sealed by the sealing structure according to any one of claims 1-8.

10. The battery according to claim 9, characterized in that: The lower plastic of the battery shell is provided with a groove, which is located below the liquid injection hole, and the bottom wall of the groove is in a stepped shape; The part of the bottom wall of the groove, which is not opposite to the liquid injection hole, is covered with a plurality of through holes, and part of the bottom wall of the groove can abut against the pole group in the battery shell.

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