Battery sealing structure

Abstract

The utility model relates to battery sealing technical field especially relates to a battery sealing structure. Battery sealing structure includes battery top cover, hole plug, hole cover and air bag, and the surface of battery top cover is provided with liquid injection hole, hole plug sets up in liquid injection hole, hole cover covers and sets up the outside of liquid injection hole, the one end of hole plug to hole cover is provided with the first limiting portion that protrudes, and air bag is sleeved in the first limiting portion, and / or, the inner surface of hole cover is provided with the second limiting portion, and air bag sets up the second limiting portion. The utility model provides battery sealing structure to solve the defect that hole plug extrusion air bag applies in prior art, through making air bag external on the first limiting portion and the second limiting portion, air bag separates from hole plug compression area, reduces the extrusion risk, and the design of first limiting portion and second limiting portion can provide stable support, and air bag installation is more simple and convenient, improves the success rate of sealing test, and enhances the quality guarantee of battery production.

Description

Technical Field

[0001] This utility model relates to the field of battery sealing technology, and in particular to a battery sealing structure. Background Technology

[0002] In lithium-ion battery production, the injection port is typically sealed using a double-sealing structure of a plug and a cap. In existing technology, the plug is generally made of rubber and is pressed into the injection port via an interference fit. A cylindrical placement hole is formed at its end, and an air bladder filled with helium is directly embedded in this hole to test the seal between the cap and the top cover. The cap covers the plug and is fixed to the top cover via laser welding.

[0003] However, during the process of pressing the plug into the injection hole, the plug undergoes elastic deformation due to the interference fit, which causes the inner wall of the placement hole to shrink. The air bladder is located inside the placement hole of the plug. The rubber plug deforms under radial compression, and the inner wall of the placement hole directly applies pressure to the air bladder. This continuous compression can easily lead to air bladder rupture or premature helium leakage. After the air bladder ruptures, the helium supply is insufficient or it is released prematurely, which will lead to a decrease in the sensitivity of helium detection and make it impossible to accurately identify welding defects in the cap. Utility Model Content

[0004] This utility model provides a battery sealing structure to solve the defects of the existing technology in the compression of the airbag by the plug. By placing the airbag externally on the first limiting part and the second limiting part, the airbag is separated from the compression area of ​​the plug, reducing the risk of compression. At the same time, the design of the first limiting part and the second limiting part can provide stable support, making the airbag installation simpler, improving the success rate of sealing test, and enhancing the quality assurance of battery production.

[0005] The battery sealing structure provided by this utility model includes: The battery top cover has liquid injection holes on its surface; A plug is disposed inside the injection hole; A cap is provided on the outside of the injection hole; An airbag is provided with a protruding first limiting part at one end of the plug facing the hole cover, and the airbag is sleeved on the first limiting part; and / or, a second limiting part is provided on the inner surface of the hole cover, and the airbag is disposed on the second limiting part.

[0006] According to the battery sealing structure provided by this utility model, when the airbag is sleeved on the first limiting part, the first limiting part is configured as an arc-shaped boss protruding from the end face of the plug, and the airbag is configured as an annular structure that matches the first limiting part.

[0007] According to the battery sealing structure provided by this utility model, the plug is further provided with a first limiting shoulder, which is located on the side surface of the plug and is used to abut against the outer surface of the battery top cover. When the airbag is fitted onto the first limiting portion, the first limiting shoulder and the first limiting portion together form the mounting portion of the airbag.

[0008] According to the battery sealing structure provided by this utility model, when the airbag is sleeved on the second limiting part, the second limiting part is configured as a boss protruding from the inner surface of the hole cover, and the airbag is configured as an annular structure that matches the second limiting part.

[0009] According to the battery sealing structure provided by this utility model, when the airbag is sleeved on the second limiting part, the second limiting part is configured as a groove provided on the inner surface of the hole cover, and the airbag is interference-fitted in the groove.

[0010] According to the battery sealing structure provided by this utility model, the groove is configured as an annular structure, and the airbag is configured as an annular structure that matches the groove.

[0011] According to the battery sealing structure provided by this utility model, the plug is further provided with a second limiting shoulder, which is disposed on the side surface of the plug and is used to abut against the inner surface of the battery top cover.

[0012] According to the battery sealing structure provided by this utility model, a first preset gap is provided between the first limiting part and the inner surface of the hole cover, and a second preset gap is provided between the second limiting shoulder and the inner surface of the battery top cover, wherein the second preset gap is less than or equal to the first preset gap.

[0013] According to the battery sealing structure provided by this utility model, the hole cover includes: When a second limiting part is provided in the first cover wall, the second limiting part is provided on the inner surface of the first cover wall; The second cover wall is disposed around the first cover wall on the side of the first cover wall facing the battery top cover, and a flange is provided at the end of the second cover wall away from the first cover wall. The flange is used for welding to the battery top cover.

[0014] According to the battery sealing structure provided by this utility model, the outer surface of the first cover wall is provided with at least one of a groove and a protrusion, and / or the inner surface of the first cover wall is provided with at least one of a groove and a protrusion.

[0015] In the battery sealing structure provided by this utility model, by placing the airbag in the first limiting part of the plug or the second limiting part of the cover, the force on the airbag during the compression process of the plug is reduced, and the airbag is not easily damaged or leaked, thereby improving the sensitivity and accuracy of helium detection.

[0016] Compared to the prior art where the airbag is embedded in the hole of the plug, the elastic deformation of the plug during the interference fit causes the hole to shrink, directly compressing the airbag and easily leading to damage and premature helium release, thus reducing the reliability of the test; the airbag of this invention is externally placed on the first and second limiting parts, away from the compression area of ​​the plug, reducing the risk of compression. At the same time, the design of the first and second limiting parts can provide stable support, making the airbag installation simpler, improving the success rate of the sealing test, and enhancing the quality assurance of battery production. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is an exploded structural diagram of a battery sealing structure provided in an embodiment of this utility model.

[0019] Figure 2 This is a cross-sectional structural diagram of a battery sealing structure provided in an embodiment of the present invention.

[0020] Figure 3 This is another exploded structural diagram of the battery sealing structure provided in this embodiment of the utility model.

[0021] Figure 4 This is a schematic cross-sectional view of another battery sealing structure provided in this embodiment of the utility model.

[0022] Figure label: 100: Battery top cover; 110: Injection hole; 200: Hole plug; 210: First limiting part; 220: First limiting shoulder; 230: Second limiting shoulder; 300: Hole cover; 310: Second limiting part; 320: First cover wall; 330: Second cover wall; 400: Airbag. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0025] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0027] Figure 1 This is an exploded structural diagram of a battery sealing structure provided in an embodiment of the present invention; Figure 2 This is a cross-sectional structural diagram of a battery sealing structure provided in an embodiment of the present invention.

[0028] See Figure 1 and Figure 2In an optional embodiment of this utility model, a battery sealing structure is provided, which includes a battery top cover 100, a plug 200, a cover 300, and an airbag 400. The surface of the battery top cover 100 is provided with an injection hole 110 for injecting electrolyte. The plug 200 is disposed inside the injection hole 110, and the two are press-fitted to provide a preliminary seal. The cover 300 covers the outside of the plug 200 and the injection hole 110 and is fixed to the battery top cover 100 by welding to form a secondary seal.

[0029] The airbag 400 is used to contain the detection gas, such as helium. A protruding first limiting part 210 is provided at the end of the plug 200 facing the cover 300, and the airbag 400 is sleeved on the first limiting part 210. Alternatively, a second limiting part 310 is provided on the inner surface of the cover 300, and the airbag 400 is disposed on the second limiting part 310. Or the airbag 400 is disposed on both the first limiting part 210 and the second limiting part 310. This structure can prevent the airbag 400 from being directly embedded inside the plug 200, thereby reducing the risk of compression.

[0030] Specifically, the first limiting part 210 can be a protruding structure at the upper end of the plug 200, such as a columnar or annular boss, and the airbag 400 is annular or bag-shaped and is directly fitted on it; the second limiting part 310 can be a groove or protrusion formed on the inner surface of the plug 300, and the airbag 400 is placed or fixed therein.

[0031] The location of the airbag 400 depends on the design requirements. For example, when the airbag 400 is only fitted on the first limiting part 210, the compression of the plug 200 will not directly affect the airbag 400; when the airbag 400 is only provided on the second limiting part 310, the cover 300 provides independent support; when the two are combined, the airbag 400 can span the gap between the plug 200 and the cover 300, or two airbags 400 can be provided, which are respectively located on the first limiting part 210 and the second limiting part 310.

[0032] In one optional embodiment of this utility model, the airbag 400 is sleeved on the first limiting part 210 of the plug 200: the first limiting part 210 is a cylindrical boss with a diameter slightly smaller than the main body of the plug 200; the airbag 400 is an annular film with an inner diameter matching the outer diameter of the cylindrical boss, and is supported by the cylindrical boss after being sleeved; the plug 200 is made of rubber and is interference-fitted to the injection hole 110, with the compression controlled at 3%-15%.

[0033] In another optional embodiment of this utility model, the airbag 400 is disposed on the second limiting part 310 of the hole cover 300: the second limiting part 310 is a circular groove on the inner surface of the hole cover 300, the airbag 400 is a flat bag shape, and is embedded in the groove for fixation; the hole cover 300 is connected to the battery top cover 100 by laser welding, and the groove depth is 0.5-2mm.

[0034] Based on Embodiment 1, the first limiting part 210 can be changed to a square column-shaped boss, and the airbag 400 is a square ring; or based on Embodiment 2, the second limiting part 310 can be replaced with a protruding structure, and the airbag 400 can be fixed by adhesive bonding or interference fit.

[0035] The battery sealing structure begins with the sealing of the injection hole 110. After the plug 200 is pressed into the injection hole 110, an interference fit achieves a preliminary seal. The cover 300 covers the plug 200 and is fixed to the battery top cover 100 by laser welding. The airbag 400 is pre-installed. If it is sleeved on the first limiting part 210 of the plug 200, the protrusion remains stable when the plug 200 is compressed, and the airbag 400 is not subjected to radial force. If it is set on the second limiting part 310 of the cover 300, the airbag 400 is independent of the plug 200 after the cover 300 is welded.

[0036] During helium detection testing, the equipment evacuates the outside of the orifice cap 300. If there are defects in the welding of the orifice cap 300, such as punctures, the negative pressure increases the pressure difference between the inside and outside of the gas bladder 400. When the pressure difference exceeds a threshold, the gas bladder 400 ruptures, and helium gas escapes from the defect and is detected. If the welding is intact, the gas bladder 400 remains intact, and no helium gas is released. Throughout the process, the position of the gas bladder 400 avoids direct compression from the deformation of the orifice plug 200, thus ensuring the reliability of the test.

[0037] See Figure 1 and Figure 2 It is understood that in the battery sealing structure provided by this utility model embodiment, by placing the airbag 400 on the first limiting part 210 of the plug 200 or the second limiting part 310 of the cover 300, the force on the airbag 400 during the compression process of the plug 200 is reduced, and the airbag 400 is not easily damaged or leaked, thereby improving the sensitivity and accuracy of helium detection.

[0038] Compared to the prior art where the airbag 400 is embedded in the mounting hole of the plug 200, the elastic deformation of the plug 200 during the interference fit causes the mounting hole to shrink, directly compressing the airbag 400, which easily leads to damage and premature release of helium, thereby reducing the reliability of the test; in this embodiment of the utility model, the airbag 400 is externally placed on the first limiting part 210 and the second limiting part 310, away from the compression area of ​​the plug 200, reducing the risk of compression. At the same time, the design of the first limiting part 210 and the second limiting part 310 can provide stable support, making the installation of the airbag 400 simpler, improving the success rate of the sealing test, and enhancing the quality assurance of battery production.

[0039] Continue reading Figure 1 and Figure 2In an optional embodiment of this utility model, when the airbag 400 is fitted onto the first limiting part 210, the first limiting part 210 is specifically configured as an arc-shaped boss protruding from the end face of the plug 200. This arc-shaped boss includes a spherical boss, a cylindrical boss as exemplified in the previous embodiments, and other arc-shaped bosses with curved surfaces. The airbag 400 is configured as an annular structure matching the first limiting part 210. The arc-shaped boss extends vertically from the end face of the plug 200, and its diameter is smaller than or larger than the diameter of the plug 200 body, forming a stepped support structure. The inner diameter of the annular airbag 400 is slightly smaller than the outer diameter of the arc-shaped boss. It is elastically expanded and fitted onto the arc-shaped boss, achieving an interference fit fixation. This fit ensures that the airbag 400 remains stable during the compression of the plug 200, preventing it from falling off or shifting.

[0040] For example, the height of the arc-shaped boss can be 0.5-2mm, providing ample space for the annular airbag 400 to be fitted. The membrane thickness of the annular airbag 400 is 5-20μm, made of insulating film such as PP, PE, or PC, and filled with helium gas at 90-105kPa. Optionally, several implementation variations can be formed through simple adjustments: In variation one, an annular groove is provided on the outer wall of the arc-shaped boss, and a corresponding rib is provided on the inner ring of the airbag 400, forming a mechanical interlock after fitting; in variation two, a guide cone surface with a gradually decreasing diameter (cone angle 15°-30°) is added to the top of the arc-shaped boss to facilitate the guidance and positioning of the annular airbag 400 during installation; in variation three, a radial lug extends from the outer edge of the annular airbag 400, which is embedded in the slot on the inner side of the hole cover 300 to achieve double fixation. In summary, the structure of the first limiting part 210 and the airbag 400 can be adaptively adjusted according to actual conditions, and will not be listed in detail here.

[0041] When the plug 200 is pressed into the injection hole 110, the rubber plug 200 body undergoes radial compression due to the interference fit. However, the arc-shaped boss is located outside the injection hole 110 and is not affected by the compression force. The annular airbag 400, which is fitted onto the arc-shaped boss, is detached from the compression area and is only subject to its own internal gas pressure. During the helium detection test, if there is a defect in the welding of the cap 300, the external negative pressure will increase the pressure difference between the inside and outside of the airbag 400. When the pressure difference exceeds the threshold, the airbag 400 will rupture at the weak point and release helium. The helium escapes through the welding defect and is captured by the detection equipment. If the welding is intact, the airbag 400 remains intact. Throughout the entire process, the sleeve structure between the airbag 400 and the arc-shaped boss maintains stable contact without any risk of relative displacement.

[0042] See Figure 1 and Figure 2 It is understood that in the battery sealing structure provided by this utility model embodiment, the positioning accuracy and anti-interference ability of the airbag 400 are optimized by matching and fitting the arc-shaped boss with the annular airbag 400. In addition, the arc-shaped surface of the arc-shaped boss can also reduce the assembly difficulty between the airbag 400 and the arc-shaped boss.

[0043] Compared to the prior art structure where the airbag 400 is embedded inside the plug 200, this embodiment of the invention allows the airbag 400 to be detached from the compression deformation zone of the plug 200, reducing the risk of breakage caused by radial extrusion force. Simultaneously, the annular structure increases the volume of the airbag 400, ensuring sufficient helium storage and improving detection sensitivity. The stepped design of the arc-shaped protrusion provides rigid support for the airbag 400, preventing displacement caused by internal battery pressure fluctuations, further improving test reliability.

[0044] Continue reading Figure 1 and Figure 2 In an optional embodiment of the present invention, when the airbag 400 is fitted onto the first limiting part 210, the plug 200 is also provided with a first limiting shoulder 220, which is provided on the side surface of the plug 200 and adapted to abut against the outer surface of the battery top cover 100; the first limiting shoulder 220 and the first limiting part 210 together form the mounting part of the airbag 400.

[0045] Specifically, the first limiting shoulder 220 is an annular flange surrounding the side wall of the plug 200, with an outer diameter larger than the diameter of the injection hole 110, ensuring that the first limiting shoulder 220 is engaged with the surface of the battery top cover 100 when the plug 200 is pressed in; the first limiting part 210 (circular boss) is located on the end face of the plug 200, and the two form a semi-recessed space—the mounting part—that accommodates the annular airbag 400. The mounting part provides axial constraint through the first limiting shoulder 220 and radial support through the first limiting part 210, so that the airbag 400 is stably embedded between the two.

[0046] Optionally, multiple variations can be constructed through structural fine-tuning during implementation. Variation 1: The first limiting shoulder 220 is a continuous annular plane, making full contact with the surface of the battery top cover 100 (e.g., Figure 1 and Figure 2 As shown), the mounting part of the airbag 400 is an L-shaped groove; Variation 2: The first limiting shoulder 220 is replaced with multiple evenly distributed arc-shaped protrusions, and ventilation gaps are formed between the protrusions to reduce assembly resistance.

[0047] During the process of the plug 200 being pressed into the injection hole 110, the first limiting shoulder 220 stops pressing when it contacts the outer surface of the battery top cover 100. At this time, the arc-shaped boss is fully exposed on the outside of the injection hole 110. After the annular airbag 400 is fitted along the arc-shaped boss, its bottom fits against the upper surface of the first limiting shoulder 220, and the side wall of the annular airbag 400 is interference-fitted with the side wall of the arc-shaped boss.

[0048] When a negative pressure is generated due to a change in the internal gas pressure of the battery, the plug 200 moves downward under the negative pressure, and the first limiting shoulder 220 abuts against the battery top cover 100 to prevent displacement; at the same time, the airbag 400 is restrained within the mounting part, eliminating the risk of detachment. During the helium inspection stage, external negative pressure acts on the cover 300. If the welding is poor, the negative pressure is transmitted to the outside of the airbag 400 through the defect. The pressure difference causes the airbag 400 to rupture and release helium gas, which escapes along the welding defect channel and is detected.

[0049] See Figure 1 and Figure 2 It is understood that in the battery sealing structure provided by this embodiment of the present invention, the first limiting shoulder 220 and the first limiting part 210 work together to construct an installation part for the airbag 400, thereby improving vibration resistance and stability. Compared with the prior art, the first limiting shoulder 220 can, firstly, prevent the plug 200 from being excessively pressed in and deformed; secondly, ensure that the installation position of the airbag 400 is constant and provide support for the airbag 400; and thirdly, reduce the impact of the negative pressure of the gas inside the battery on the plug 200.

[0050] Figure 3 This is another exploded structural diagram of the battery sealing structure provided in this embodiment of the utility model; Figure 4 This is a schematic cross-sectional view of another battery sealing structure provided in this embodiment of the utility model.

[0051] See Figure 3 and Figure 4 In an optional embodiment of the present invention, when the airbag 400 is fitted onto the second limiting part 310 of the hole cover 300, the second limiting part 310 can be specifically designed as a boss structure protruding from the inner surface of the hole cover 300, and the airbag 400 is configured as an annular structure matching the shape of the boss.

[0052] The boss extends vertically from the inner surface of the cover 300, and its diameter is smaller than the inner diameter of the cover 300, forming a stable support base. The inner diameter of the annular airbag 400 is slightly smaller than the outer diameter of the boss. It is elastically expanded and fitted onto the outside of the boss or fixed with adhesive to ensure that there is no loosening after assembly. The airbag 400 can be made of insulating film such as PP, PE or PC, with a film thickness of 5-20μm, and is filled with helium gas at 90-105kPa.

[0053] Optionally, the implementation can be expanded to multiple structural forms, the first embodiment ( Figure 4 (As shown): The boss is a solid cylinder with a smooth surface, and the airbag 400 is directly fitted to form an interference fit; Second embodiment: The boss is a solid prism with a smooth surface, and the airbag 400 is directly fitted to form an interference fit; Third embodiment: The boss is replaced with a sphere with a smooth surface, and the airbag 400 is directly fitted to form a fit.

[0054] During battery assembly, the annular airbag 400 is first fitted or fixed onto the second limiting part 310 of the hole cover 300; then, the hole cover 300 is placed over the outside of the injection hole 110, so that the hole plug 200 is located below the hole cover 300; the periphery of the hole cover 300 is sealed and fixed to the battery top cover 100 by laser welding. After welding, the airbag 400 is located in the closed space between the inner surface of the hole cover 300 and the upper end face of the hole plug 200, without physical contact with the hole plug 200. During helium detection testing, the equipment evacuates the outside of the hole cover 300: if there is a defect in the welding of the hole cover 300 (such as a microcrack), the external negative pressure is transmitted to the space where the airbag 400 is located through the defect. When the pressure difference between the inside and outside of the airbag 400 exceeds the threshold, the airbag 400 ruptures and releases helium. The helium escapes along the welding defect channel and is identified by the detection equipment; if the welding is intact, the pressure difference between the inside and outside of the airbag 400 is insufficient, maintaining its integrity.

[0055] See Figure 3 and Figure 4 It is understood that in the battery sealing structure provided by this utility model embodiment, by integrating the airbag 400 into the boss of the hole cover 300, physical isolation between the airbag 400 and the hole plug 200 can be achieved. Compared with the prior art, the airbag 400 is fixed to the boss of the hole cover 300, which improves the compression of the airbag 400 by radial contraction when the hole plug 200 is interference-fitted (in the prior art, the airbag 400 is directly subjected to force when embedded inside the hole plug 200); secondly, the airbag 400 can be installed before the hole cover 300 is welded, avoiding the operational difficulties of manually inserting the airbag 400 after the hole plug 200 is compressed in the prior art.

[0056] In an optional embodiment of this utility model, unlike the aforementioned embodiments, when the airbag 400 is selected to be disposed on the second limiting part 310 of the orifice cover 300, the second limiting part 310 can specifically be a groove structure disposed on the inner surface of the orifice cover 300, and the airbag 400 is fixed in the groove by interference fit. The groove is recessed inward from the inner surface of the orifice cover 300, and the diameter of the groove opening is slightly smaller than the diameter of the airbag 400 in its natural state, forming a compression assembly space; the airbag 400 is made of elastic film material (such as PP / PE / PC), and after deforming and embedding into the groove under pressure, it relies on the material's elasticity to fit tightly against the groove wall.

[0057] Optionally, various groove shapes and mating methods can be extended during implementation. First embodiment: The groove is a circular blind hole. After the airbag 400 is pressed in, it protrudes in a hemispherical shape, and the height of the protrusion is lower than the groove depth. Second embodiment: The groove is replaced by multiple independent slots in a rectangular array (such as a 3×3 grid). The airbag 400 is correspondingly divided into multi-cavity units, and each unit is independently embedded in the slot. Third embodiment: The groove is set as a ring structure, and the shape of the airbag 400 corresponds to it. After being pressed in, the two abut against each other and limit each other.

[0058] Before welding the orifice cap 300, pressure is applied to the airbag 400 aligned with the groove. The airbag 400 deforms under pressure and embeds itself into the groove, secured by an interference fit. The orifice cap 300 then covers the injection hole 110 and is sealed to the battery top cover 100 via laser welding. The airbag 400 is housed within the groove, its outer surface flush with or slightly convex to the inner surface of the orifice cap 300, avoiding contact with the orifice plug 200. During helium detection, an external vacuum is created to form a negative pressure environment. If there is a defect in the welding of the orifice cap 300, the negative pressure acts on the outside of the airbag 400 through the defect channel. When the pressure difference exceeds a threshold, the airbag 400 ruptures, and helium escapes along the defect and is detected. If the welding is intact, the airbag 400 remains sealed.

[0059] It is understood that in the battery sealing structure provided by this utility model embodiment, the airbag 400 is embedded and fixed by the interference fit of the groove, which has both positioning reliability and space compactness. Compared with the prior art, the airbag 400 is embedded in the groove of the hole cover 300 and is removed from the compression area of ​​the hole plug 200, which can improve the risk of radial compression of the airbag 400 by the deformation of the hole plug 200 in the prior art; secondly, the interference fit provides continuous pressure, which can avoid the displacement of the airbag 400 caused by vibration or air pressure fluctuation.

[0060] Continue reading Figure 2 and Figure 4 In an optional embodiment of this utility model, a second limiting shoulder 230 is added to the plug 200 in the battery sealing structure. The second limiting shoulder 230 is disposed on the side surface of the plug 200 and is adapted to abut against the inner surface of the battery top cover 100. The second limiting shoulder 230 is an annular flange or a split protrusion surrounding the side wall of the plug 200, and its outer diameter is slightly larger than the inner diameter of the injection hole 110. After installation, it can abut against the inner wall of the top cover inside the injection hole 110, forming an upward movement limit for the plug 200. The second limiting shoulder 230 and the first limiting shoulder 220 (if present) work together to achieve bidirectional displacement constraint of the plug 200: the first limiting shoulder 220 restricts downward movement, and the second limiting shoulder 230 restricts upward movement.

[0061] Optionally, multiple variations can be constructed in conjunction with the aforementioned embodiments during implementation. A first optional embodiment: the plug 200 has a circular boss (first limiting part 210), a first limiting shoulder 220, and a second limiting shoulder 230. The first limiting shoulder 220 abuts against the outer surface of the top cover, and the second limiting shoulder 230 abuts against the inner surface of the top cover. The airbag 400 is sleeved on the boss. A second optional embodiment: the plug 200 only has the second limiting shoulder 230, and the airbag 400 is located in the groove of the cover 300. The second limiting shoulder 230 prevents the plug 200 from being squeezed out by the internal air pressure of the battery, leading to sealing leakage. A third optional embodiment: the second limiting shoulder 230 is replaced by multiple evenly distributed elastic claws. After being compressed and contracted, the claws pass through the injection hole 110, reset, and unfold to abut against the inner wall of the top cover.

[0062] When the plug 200 is pressed into the injection hole 110, the second limiting shoulder 230 stops moving after contacting the inner surface of the battery top cover 100, ensuring that the plug 200 is at the designed depth. If the internal gas pressure increases during battery use, the plug 200 is subjected to an upward thrust, and the second limiting shoulder 230 abuts against the inner wall of the battery top cover 100 to prevent upward movement, maintaining a stable sealing interface. During the helium detection stage, when external negative pressure is applied, the second limiting shoulder 230 can also keep the position of the plug 200 constant, preventing abnormal pressure on the airbag 400 due to displacement.

[0063] See Figure 2 and Figure 4 It is understood that in the battery sealing structure provided by this utility model embodiment, the upward movement constraint of the plug 200 is achieved through the second limiting shoulder 230, thus improving the dynamic sealing guarantee. Compared with the prior art, the first limiting shoulder 220 and the second limiting shoulder 230 can work together to restrict the vertical movement of the plug 200, reducing the risk of sealing failure caused by positive / negative pressure fluctuations inside the battery; secondly, the second limiting shoulder 230 can ensure the consistency of the plug 200's pressing depth, avoiding poor sealing caused by manual pressing errors; in addition, the stable position of the plug 200 can reduce accidental compression of the airbag 400, improving the reliability of helium detection.

[0064] Continue reading Figure 2 and Figure 4 In an optional embodiment of this utility model, in the battery sealing structure, a first preset gap H1 is provided between the first limiting part 210 and the inner surface of the hole cover 300, and a second preset gap H2 is provided between the second limiting shoulder 230 of the hole plug 200 and the inner surface of the battery top cover 100, and the size of the second preset gap is less than or equal to the first preset gap. This gap system constructs a buffer space to adapt to fluctuations in the internal air pressure of the battery.

[0065] Specifically, the first preset gap refers to the vertical distance between the highest point of the first limiting part 210 at the end of the plug 200 and the inner surface of the cover 300; the second preset gap refers to the vertical distance between the upper surface of the second limiting shoulder 230 and the inner surface of the battery top cover 100, and satisfies the relationship: the second preset gap ≤ the first preset gap.

[0066] In an optional embodiment, after the plug 200 is installed into the injection hole 110, the plug 200 can be pressed further into the injection hole 110 until the bottom of the first limiting shoulder 220 abuts against the outer surface of the battery top cover 100. At this time, there is a gap between the top surface of the first limiting shoulder 220 and the inner surface of the hole cover 300, which is the first preset gap. The second limiting shoulder 230 does not abut against the inner surface of the battery top cover 100 at this time, and there is a certain gap between the two, which is the second preset gap. The second preset gap is equal to the first preset gap.

[0067] During use, the internal air pressure of the battery may increase due to environmental factors such as temperature or air pressure, which will push the plug 200 upward, that is, move it away from the battery. During this process, the first preset gap and the second preset gap allow the plug 200 to have reasonable room for movement, and the displacement of the plug 200 is absorbed by the first preset gap and the second preset gap.

[0068] When the plug 200 moves upward to the point where the second limiting shoulder 230 abuts against the inner surface of the battery top cover 100, the first preset gap and the second preset gap disappear simultaneously. At this time, the first limiting part 210 of the plug 200 abuts against the inner surface of the cover 300, thus forming a double limiting structure where the first limiting part 210 abuts against the cover 300 and the second limiting shoulder 230 abuts against the battery top cover 100. When the internal air pressure of the battery is restored, the plug 200 moves downward under the attraction of the negative pressure inside the battery until the first limiting shoulder 220 abuts against the outer surface of the battery top cover 100. At this time, the first preset gap and the second preset gap reappear completely.

[0069] See Figure 2 and Figure 4 It is understood that in the battery sealing structure provided by this utility model embodiment, dynamic sealing optimization is achieved through a gap system and a dual-gap linkage mechanism. Specifically, when the internal air pressure of the battery increases, the second preset gap and the first preset gap decrease synchronously during the upward movement of the plug 200 until the second limiting shoulder 230 abuts against the inner surface of the battery top cover 100 and the first limiting part 210 abuts against the inner surface of the hole cover 300, forming a double rigid limit. When the air pressure recovers, the plug 200 automatically resets under the negative pressure attraction, and the first limiting shoulder 220 abuts against the outer surface of the top cover again, and the dual gaps return to their initial state. The synchronous disappearance of the dual gaps triggers the dual limit, providing mechanical stop protection under extreme air pressure. Moreover, the dual gap design allows the battery to adaptively stabilize the internal pressure to avoid the impact of excessive or insufficient internal pressure on battery stability.

[0070] Continue reading Figure 2 and Figure 4In an optional embodiment of this utility model, the hole cover 300 structure includes a first cover wall 320 and a second cover wall 330. The first cover wall 320 serves as the main body, and its inner surface, when provided with a second limiting part 310, supports the airbag 400 fixing structure (such as a boss or groove). The second cover wall 330 is circumferentially disposed along the side of the first cover wall 320 facing the battery top cover 100. The end of the second cover wall 330 away from the first cover wall 320 is provided with a flange, which is used for sealing connection with the battery top cover 100 by laser welding. This cover wall design forms a bent transition structure, wherein the included angle between the first cover wall 320 and the second cover wall 330 can be adaptively set, preferably 90°, and the flange width can be adaptively set to provide sufficient welding contact surface.

[0071] During assembly, the airbag 400 is first fixed to the second limiting part 310 of the first cover wall 320 (if the second limiting part 310 is present); then the hole cover 300 is placed over the injection hole 110, so that the flange of the second cover wall 330 fits against the surface of the battery top cover 100; a sealing ring is formed by welding along the circumferential direction of the flange using a laser beam. During the welding process, the bending structure of the first cover wall 320 and the second cover wall 330 disperses thermal stress, which can reduce deformation in the weld area.

[0072] See Figure 2 and Figure 4 It is understood that in the battery sealing structure provided by this utility model embodiment, the structure of the bent cover wall optimizes the welding reliability and stress distribution. Specifically, the angle design between the first cover wall 320 and the second cover wall 330 can disperse the thermal stress of laser welding and reduce the risk of explosion caused by direct welding of the flat hole cover 300. Secondly, the flange can provide a wide welding surface, which can effectively improve the uniformity of weld penetration. The bending structure at the flange can also disperse the thermal stress of laser welding and reduce the risk of explosion caused by direct welding of the hole cover 300. In addition, compared with the rigid flat cover body, which is prone to false welding due to unevenness, the bending structure can compensate for the flatness tolerance of the battery top cover 100 and ensure that the flange fits the entire circumference.

[0073] Continue reading Figure 2 and Figure 4 In an optional embodiment of this utility model, the outer surface of the first cover wall 320 is provided with at least one of a groove and a protrusion, and / or the inner surface of the first cover wall 320 is provided with at least one of a groove and a protrusion. The groove is a regular recessed pit extending inward from the surface of the cover wall; the protrusion is a reinforcing rib protruding outward from the surface of the cover wall. These structures can optimize mechanical properties by changing the local stiffness of the cover wall.

[0074] Optionally, multiple variations can be constructed in combination with the morphology of the cap wall during implementation, as in Example 1 ( Figure 2As shown): The outer surface of the first cover wall 320 has an annular groove, and the inner surface has an annular protrusion; Embodiment 2: The inner surface of the first cover wall 320 has a cross-shaped protrusion, and the intersection forms a groove, and the outer surface is smooth; Variation: The groove and the protrusion can be combined to form a wave pattern, covering the entire surface of the first cover wall 320.

[0075] During laser welding, the groove and raised structures can disperse thermal stress: the groove accommodates the thermal expansion and deformation of the material, while the raised structures provide additional support points to suppress cover warping. Secondly, if the internal gas pressure abnormally increases during battery use, the raised structures can enhance the bending strength of the cover, while the groove absorbs local deformation energy. Furthermore, under the external negative pressure during the helium detection stage, the groove and raised structures can maintain the stable shape of the cover structure, preventing deformation from interfering with the airbag position 400.

[0076] See Figure 2 and Figure 4 It is understood that in the battery sealing structure provided by this utility model embodiment, the sink can absorb welding heat deformation and reduce microcracks in the flat cover caused by thermal stress; the protrusion can provide local stiffness reinforcement and improve the compressive strength of the cover; in addition, the above structure can also prevent the cover wall from being squeezed by abnormal air pressure.

[0077] It should be noted that the technical solutions in the various embodiments of this utility model can be combined with each other, but the basis for such combination is that they can be implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist, that is, it is not within the protection scope of this utility model.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A battery sealing structure, characterized in that, include: The battery top cover has liquid injection holes on its surface; A plug is disposed inside the injection hole; A cap is provided on the outside of the injection hole; An airbag is provided with a protruding first limiting part at one end of the plug facing the hole cover, and the airbag is sleeved on the first limiting part; and / or, a second limiting part is provided on the inner surface of the hole cover, and the airbag is disposed on the second limiting part.

2. The battery sealing structure according to claim 1, characterized in that, When the airbag is fitted onto the first limiting part, the first limiting part is configured as an arc-shaped boss protruding from the end face of the plug, and the airbag is configured as a ring structure that matches the first limiting part.

3. The battery sealing structure according to claim 2, characterized in that, The plug is also provided with a first limiting shoulder, which is located on the side surface of the plug and is used to abut against the outer surface of the battery top cover. When the airbag is fitted onto the first limiting portion, the first limiting shoulder and the first limiting portion together form the mounting portion of the airbag.

4. The battery sealing structure according to claim 1, characterized in that, When the airbag is fitted onto the second limiting part, the second limiting part is configured as a boss protruding from the inner surface of the hole cover, and the airbag is configured as an annular structure that matches the second limiting part.

5. The battery sealing structure according to claim 1, characterized in that, When the airbag is fitted onto the second limiting part, the second limiting part is configured as a groove on the inner surface of the hole cover, and the airbag is interference-fitted into the groove.

6. The battery sealing structure according to claim 5, characterized in that, The groove is configured as a ring structure, and the airbag is configured as a ring structure that matches the groove.

7. The battery sealing structure according to any one of claims 1 to 6, characterized in that, The plug is also provided with a second limiting shoulder, which is disposed on the side surface of the plug and is used to abut against the inner surface of the battery top cover.

8. The battery sealing structure according to claim 7, characterized in that, A first preset gap is provided between the first limiting part and the inner surface of the hole cover, and a second preset gap is provided between the second limiting shoulder and the inner surface of the battery top cover. The second preset gap is less than or equal to the first preset gap.

9. The battery sealing structure according to any one of claims 1 to 6, characterized in that, The orifice cover includes: When a second limiting part is provided in the first cover wall, the second limiting part is provided on the inner surface of the first cover wall; The second cover wall is disposed around the first cover wall on the side of the first cover wall facing the battery top cover, and a flange is provided at the end of the second cover wall away from the first cover wall. The flange is used for welding to the battery top cover.

10. The battery sealing structure according to claim 9, characterized in that, The outer surface of the first cover wall is provided with at least one of a groove and a protrusion, and / or the inner surface of the first cover wall is provided with at least one of a groove and a protrusion.

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