Sealing nail, cover plate assembly and battery

Abstract

The utility model provides a sealing nail, a cover plate assembly and a battery, and relates to the technical field of batteries, the sealing nail comprises a sealing cover and a rubber nail, and the sealing cover comprises a detection cavity and a notch used for penetrating through the interior and the exterior of the detection cavity; at least part of the plastic nail is hermetically connected to one side of the sealing cover, and a detection cavity is formed between the plastic nail and the sealing cover. The rubber nail is connected to the sealing cover in a sealed mode, the detection cavity is formed above the interference fit position of the rubber nail and the liquid injection hole, and therefore the welding state of the sealing nail can be judged by detecting whether to-be-detected matter leaks out of the detection cavity or not. For example, if the welding position of the sealing cover has a welding failure, the to-be-detected substance in the detection cavity escapes to the outside of the sealing cover along the welding gap through the notch, whether the to-be-detected substance leaks out of the sealing nail or not is detected outside the sealing nail, the problem of missing detection or false detection is avoided, the welding seam defect of the sealing nail can be reduced, and the detection efficiency is improved. The production efficiency of the battery is improved.

Description

Technical Field

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

[0002] In the production process of lithium-ion batteries, after the battery is filled with liquid, the battery's injection hole needs to be sealed. In the related art, the method of sealing the injection hole is to first draw negative pressure inside the battery and fill it with helium before sealing, then insert a rubber nail into the battery's injection hole, press the sealing rubber nail to be flush with the injection hole, and then cover the injection hole with a metal sealing cover and perform laser welding. After the sealing is completed, the battery's sealing can be tested by detecting whether there is gas leakage at the battery's injection hole.

[0003] However, in the related art, the sealing nail and the injection hole are usually interference fit, which prevents the helium filled into the battery from leaking out. Even if there is a problem with the welded metal sealing cover, the helium detection equipment will determine that the problematic battery is a reasonable battery. Therefore, the nail of the problematic battery is prone to loosening during long-term transportation and use, causing battery leakage, which poses a major safety hazard. At the same time, the injection hole sealing method in the related art has the problem of cumbersome process. Utility Model Content

[0004] The purpose of the utility model is to provide a sealing nail, a cover plate assembly and a battery to solve the technical problem that the sealing method of the battery filling hole in the prior art is prone to missed detection or misdetection. The preferred technical solution among the many technical solutions provided by the utility model can produce many technical effects as described below.

[0005] In a first aspect, the present application provides a sealing nail, comprising: a sealing cover and a glue nail, the sealing cover comprising a detection cavity and a slot for passing through the inside and outside of the detection cavity; at least part of the glue nail is sealingly connected to one side of the sealing cover to form a detection cavity therebetween.

[0006] In one or more embodiments of the present application, a first boss is provided on the side of the sealing cover facing the glue nail, a cavity is formed inside the first boss, a second boss is provided on the side of the cavity close to the sealing cover, a detection cavity is formed in the second boss, and a accommodating cavity is formed in the cavity and on the side of the second boss away from the sealing cover, and at least part of the glue nail is sealed and connected to the accommodating cavity and the second boss.

[0007] In one or more embodiments of the present application, the notch is extended from the second boss to the first boss along the radial direction of the sealing cover, so that the notch passes through the inside and outside of the detection cavity.

[0008] In one or more embodiments of the present application, the inner surface of the detection cavity is coated with a substance that sublimates when heated, and the notch allows the substance to flow out of the detection cavity from the inside to the outside after being sublimated when heated.

[0009] In one or more embodiments of the present application, the adhesive nail includes:

[0010] A base, at least a portion of which forms an interference fit with the accommodating cavity and the second boss;

[0011] The guide block is connected to the base and is located at a side away from the sealing cover. At least one plane is arranged on the outer side wall of the guide block, and the plane is extended along the axial direction of the guide block.

[0012] In one or more embodiments of the present application, a first boss forms a chamfered structure at the outer edge of the accommodating cavity; a protrusion is provided on the inner wall of the accommodating cavity connected to the chamfered structure, and when the base is installed in the accommodating cavity, the outer wall of the base and the protrusion on the inner wall of the accommodating cavity form an interference fit.

[0013] In one or more embodiments of the present application, the protrusion is a protruding structure with an arc, and the plurality of protrusions are arranged at intervals along the inner wall of the accommodating cavity and connected to the second boss.

[0014] In a second aspect, the present application further provides a cover plate assembly, comprising:

[0015] A cover plate, wherein a liquid injection hole is provided on the cover plate; and

[0016] As described in the first aspect, the sealing nail seals the injection hole.

[0017] In one or more embodiments of the present application, the injection hole includes a first cavity, a second cavity and a third cavity which are sequentially arranged toward the interior of the cover plate, wherein the sealing cover is welded and sealed to the first cavity, the first boss is accommodated in the second cavity, and at least part of the glue nail is sealed and installed in the third cavity.

[0018] In a third aspect, the present application further provides a battery, comprising the cover plate assembly described in the second aspect.

[0019] Based on the above technical solution, the sealing nail, cover plate assembly and battery provided by the present application have at least the following beneficial technical effects:

[0020] A sealing nail provided in an embodiment of the present application is provided with a detection cavity and a notch for passing through the inside and outside of the detection cavity on the sealing cover, at least part of the glue nail is sealed and connected to one side of the sealing cover and a detection cavity is formed between the sealing cover and the glue nail, then by sealing the glue nail to the sealing cover, the end of the glue nail away from the sealing cover can form a primary seal with the injection hole through interference fit, and the sealing cover and the injection hole are fixed by welding to form a secondary seal, and since the detection cavity is arranged above the interference fit between the glue nail and the injection hole, the welding state of the sealing nail can be judged by detecting whether the substance to be detected in the detection cavity has leaked out. For example: if welding failure occurs at the welding part of the sealing cover, the substance to be detected in the detection cavity will escape to the outside of the sealing cover through the notch along the welding gap, and it is sufficient to detect whether the substance to be detected has leaked out on the outside of the sealing nail, without the problem of missed detection or false detection, and the weld defects of the sealing nail can be reduced, thereby improving the production efficiency of the battery.

[0021] The cover plate assembly provided by the embodiment of the present application includes a cover plate and the sealing pin described in the first aspect, and a liquid injection hole is provided on the cover plate; the sealing pin seals the liquid injection hole. A primary seal is formed between the rubber pin of the sealing pin and the liquid injection hole through interference fit, and the liquid injection hole and the sealing cover of the sealing pin are fixed by laser welding to form a secondary seal. When welding failure occurs at the welding part, the substance to be detected in the detection cavity of the sealing pin flows out to the outside of the detection cavity and escapes to the outside of the sealing cover along the welding gap. By detecting the substance to be detected on the outside of the sealing pin, the welding state of the sealing pin can be judged, and there will be no problems of missed detection or false detection, which can reduce the weld defects of the sealing pin and improve the production efficiency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0023] Figure 1 A schematic diagram of the three-dimensional structure of a sealing pin provided in one or more embodiments of the present application;

[0024] Figure 2 A bottom view schematic diagram of the sealing pin provided in one or more embodiments of the present application;

[0025] Figure 3 for Figure 2 AA cross section in;

[0026] Figure 4 A schematic diagram of a three-dimensional structure of a sealing nail provided in one or more embodiments of the present application from another perspective;

[0027] Figure 5 A schematic diagram of a three-dimensional structure of a sealing cover provided in one or more embodiments of the present application;

[0028] Figure 6 A schematic diagram of the three-dimensional structure of a rubber nail provided in one or more embodiments of the present application;

[0029] Figure 7 A schematic diagram of an exploded structure of a cover plate assembly provided for one or more embodiments of the present application;

[0030] Figure 8 A cross-sectional view of a cover plate assembly provided for one or more embodiments of the present application;

[0031] Fig. 9 A block diagram of an airtightness detection system provided for one or more embodiments of the present application.

[0032] In the figure: 1-cover plate; 2-sealing nail; 3-negative pressure exhaust device; 4-detection reagent device; 5-visual detection device; 10-liquid injection hole; 101-first cavity; 102-second cavity; 103-third cavity; 21-sealing cover; 22-glue nail; 210-cavity; 211-detection cavity; 212-slot; 213-first boss; 214-second boss; 215-accommodating cavity; 216-bump; 217-chamfered structure; 221-base; 222-guide block; 223-plane. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0035] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] In the production process of lithium batteries, after the battery is filled with liquid and before the injection hole is sealed, a certain amount of special gas such as helium needs to be injected into the battery, so that after the injection hole is sealed, the sealing of the battery injection hole can be detected by detecting whether there is gas leakage in the battery injection hole. In the related art, it is usually to first pump negative pressure into the battery and fill it with helium, then insert a glue nail into the injection hole, press the glue nail to be flush with the injection hole, and then cover the injection hole with a metal sealing cover and perform laser welding. Usually, the interference fit between the glue nail and the injection hole will prevent the helium inside the battery from leaking out. Even if there is a problem with the welding of the metal sealing cover, the helium detection equipment cannot detect the helium, and then the problem battery is judged as a qualified battery, which makes the battery have a major safety hazard during long-term use. At the same time, the sealing method of the battery injection hole in the related art, that is, the process of pumping negative pressure helium to fill it with helium and inserting the glue nail and welding the sealing cover helium detection is relatively cumbersome, and it is impossible to effectively confirm the sealing of the battery, and it is impossible to effectively confirm whether the battery has the risk of leakage, and it is easy to have problems of missed detection or false detection.

[0038] Based on the above considerations, in order to solve the technical problem in the prior art that the sealing method of the battery filling hole is prone to missed detection or false detection, the present application provides a sealing nail, including: a sealing cover and a rubber nail, the sealing cover includes a detection cavity and a groove for passing through the inside and outside of the detection cavity; at least part of the rubber nail is sealed and connected to one side of the sealing cover to form a detection cavity.

[0039] By providing a detection cavity and a notch for passing through the inside and outside of the detection cavity on the sealing cover, at least part of the glue nail is sealed and connected to one side of the sealing cover and a detection cavity is formed between the sealing cover and the glue nail. Then, by sealing and connecting the glue nail to the sealing cover, the end of the glue nail away from the sealing cover can form a primary seal with the injection hole through an interference fit, and the sealing cover and the injection hole are fixed by welding to form a secondary seal. Since the detection cavity is arranged above the interference fit between the glue nail and the injection hole, the welding state of the sealing nail can be judged by detecting whether the substance to be detected in the detection cavity has leaked out. For example: if welding failure occurs at the welding part of the sealing cover, the substance to be detected in the detection cavity will escape to the outside of the sealing cover through the notch along the welding gap. It is sufficient to detect whether the substance to be detected has leaked out on the outside of the sealing nail, and there will be no problems of missed detection or false detection. The weld defects of the sealing nail can be reduced, and the production efficiency of the battery can be improved.

[0040] The sealing nail of the present application can be used for sealing the liquid injection hole of the cover plate of lithium-ion batteries or other batteries, or for devices in other fields that require sealing holes.

[0041] The technical solution of the present application is described in detail below in conjunction with the accompanying drawings.

[0042] First, please refer to Figures 1 to 3 An embodiment of the present application provides a sealing nail, including: a sealing cover 21 and a glue nail 22, the sealing cover 21 includes a detection cavity 211 and a notch 212 for passing through the inside and outside of the detection cavity 211; at least part of the glue nail 22 is sealed and connected to one side of the sealing cover 21 to form the detection cavity 211 therebetween.

[0043] It can be understood that the glue nail 22 can be a component that forms a primary seal with the injection hole, the sealing cover 21 can be a component that forms a secondary seal with the injection hole, and the detection cavity 211 is formed on the side of the sealing cover 21 facing the glue nail 22. At least part of the structure of the glue nail 22 is sealed and connected to the side of the sealing cover 21 where the detection cavity 211 is formed, and the detection cavity 211 is formed between the sealing cover 21 and the glue nail 22.

[0044] In the technical solution of the embodiment of the present application, a detection cavity 211 and a notch 212 for passing through the inside and outside of the detection cavity 211 are provided on the sealing cover 21, at least part of the glue nail 22 is sealed and connected to one side of the sealing cover 21 and a detection cavity 211 is formed between the sealing cover 21 and the glue nail 22. Then, by sealingly connecting the glue nail 22 to the sealing cover 21, the end of the glue nail 22 away from the sealing cover 21 can form a primary seal with the injection hole through an interference fit, and the sealing cover 21 and the injection hole are fixed by welding to form a secondary seal. Since the detection cavity 211 is arranged above the interference fit between the glue nail 22 and the injection hole, the welding state of the sealing nail can be judged by detecting whether the substance to be detected in the detection cavity has leaked out. For example, if welding failure occurs at the welding part of the sealing cover 21, the substance to be detected in the detection cavity 211 will escape to the outside of the sealing cover through the notch 212 along the welding gap. It is only necessary to detect whether there is leakage of the substance to be detected on the outside of the sealing nail 2 without missing or misdetecting the problem. The weld defects of the sealing nail 2 can be reduced, thereby improving the production efficiency of the battery.

[0045] Please refer to Figure 1 and Figure 3A first boss 213 is provided on the side of the sealing cover 21 facing the glue nail 22, a cavity 210 is formed inside the first boss 213, a second boss 214 is provided on the side of the cavity 210 close to the sealing cover 21, a detection cavity 211 is formed in the second boss 214, and a receiving cavity 215 is formed in the cavity 210 and on the side of the second boss 214 away from the sealing cover 21, and at least part of the glue nail 22 is sealed and connected to the receiving cavity 215 and the second boss 214.

[0046] Among them, the first boss 213 can be an annular boss. The cavity 210 formed inside the first boss 213 can be understood as: the cavity 210 is formed inside the first boss 213 toward its center. The second boss 214 is provided on the side near the sealing cover 21 in the cavity 210, which can be understood as: the second boss 214 is formed between the sealing cover 21 and the first boss 213 around the inner side wall of the first boss 213, the top wall of the second boss 214 is connected to one side of the sealing cover 21, the side wall of the second boss 214 is connected to the inner side wall of the first boss 213, and the second boss 214 can be an annular boss. The detection cavity 211 is formed inside the second boss 214 toward its center. The accommodating cavity 215 is formed in the cavity 210 and on the side of the second boss 214 away from the sealing cover 21, which can be understood as: the accommodating cavity 215 is formed in the cavity 210 on the side of the second boss 214 away from the sealing cover 21.

[0047] In the technical solution of the embodiment of the present application, through the above-mentioned arrangement, at least part of the glue nail 22 can be sealed and connected between the accommodating cavity 215 and the second boss 214, and the glue nail 22 can be installed on the sealing cover 21, so that a detection cavity 211 can be formed between the glue nail 22 and the sealing cover, so that the detection cavity 211 is formed above the interference fit between the glue nail 22 and the injection hole, and then by arranging a substance that can flow out in the detection cavity 211, the substance can flow out to the outside of the detection cavity 211 through the groove 212. If welding failure occurs at the welding part of the sealing cover 21, the substance in the detection cavity 211 flows out to the outside of the detection cavity 211 and escapes to the outside of the sealing cover 21 along the welding gap. By detecting the substance on the outside of the sealing nail, the welding state of the sealing nail can be judged, and there will be no problems of missed detection or false detection. The weld defects of the sealing nail can be reduced, and the production efficiency of the battery can be improved.

[0048] In some embodiments, please refer to Figure 4 and Figure 5 The notch 212 is extended from the second boss 214 to the first boss 213 along the radial direction of the sealing cover 21 , so that the notch 212 passes through the inside and outside of the detection cavity 211 .

[0049] The number of the notches 212 may be one or more. The plurality of notches 212 may be arranged at intervals around the annular first boss 213 and the second boss 214. The first boss 213 and the second boss 214 may be disconnected at the notch 212, so that the notch 212 can pass through the inside and outside of the detection cavity 211.

[0050] In the technical solution of the embodiment of the present application, the notch 212 is extended from the second boss 214 to the first boss 213 along the radial direction of the sealing cover 21, so that the notch 212 can pass through the inside and outside of the detection cavity 211, so that the substance in the detection cavity 211 can flow out to the outside of the detection cavity 211 through the notch 212. Then, when welding failure occurs at the welding part of the sealing cover 21, the substance in the detection cavity 211 can escape to the outside of the sealing cover 21 along the welding gap. By detecting the substance on the outside of the sealing pin, the welding state of the sealing pin can be judged without missing detection or false detection. The weld defects of the sealing pin can be reduced, and the production efficiency of the battery can be improved.

[0051] In some embodiments, the inner surface of the detection cavity 211 is coated with a substance that sublimates when heated, and the notch 212 allows the substance to flow out of the detection cavity 211 after being sublimated when heated.

[0052] The substance that is heated and sublimated may be a color developer, such as iodine powder, so as to facilitate direct observation and identification of whether the color developer overflows.

[0053] In the technical solution of the embodiment of the present application, a substance that sublimates when heated is coated on the inner surface of the detection cavity 211. During the laser welding process of the sealing cover 21, the welding heat will cause the color developer, such as iodine powder, to sublime when heated. When welding failure occurs at the welding part of the sealing cover 21, iodine vapor can escape through the welding gap to the outside of the sealing cover 21, and react with the detection agent in the external detection device to develop a color. By identifying the color change, it can be determined whether there is a problem of poor welding of the sealing pin. The detection effect is high, and the detection accuracy is also high, and there will be no problems of missed detection or false detection.

[0054] In some embodiments, please refer to Figure 6 The glue nail 22 includes: a base 221, at least a part of the base 221 forms an interference fit with the accommodating cavity 215 and the second boss 214; a guide block 222, which is connected to the base 221 and is located on a side away from the sealing cover 21, and at least one plane 223 is provided on the outer side wall of the guide block 222, and the plane 223 is extended along the axial direction of the guide block 222.

[0055] Among them, the base 221 and the guide block 222 can be integrally formed. At least part of the base 221 forms an interference fit with the accommodating cavity 215 and the second boss 214, which can be understood as the end of the base 221 away from the guide block 222 is installed in the accommodating cavity 215, and the top of the guide block 222 is abutted against the second boss 214, and the outer periphery of the guide block 222 is interference fit with the accommodating cavity 215, so that part of the base 221 is sealed and connected with the accommodating cavity 215 and the second boss 214. The base 221 can be cylindrical. The maximum diameter of the guide block 222 can be equal to the diameter of the base 221. A plurality of planes 223 can be arranged around the outer peripheral wall of the guide block 222 at equal intervals.

[0056] In the technical solution of the embodiment of the present application, through the above-mentioned arrangement, the base 221 can be sealed and connected to the accommodating cavity 215 of the sealing cover 21, and has an interference fit with the accommodating cavity 215 and the second boss 214, so that the glue nail 22 can be sealed and installed in the sealing cover 21 through the base 221, and the guide block 222 can facilitate the installation of the glue nail 22 and the sealing cover 21 into a sealing nail, which is convenient for installation in the injection hole 10.

[0057] In some embodiments, the depth of the accommodating cavity 215 is smaller than the axial length of the base 221 so that part of the base 221 forms an interference fit with the accommodating cavity 215 and the second boss 214, while the remaining part of the base 221 protruding from the accommodating cavity 215 can form an interference fit with the injection hole 10.

[0058] In some embodiments, please refer to Figure 4 The first boss 213 is formed with a chamfered structure 217 at the outer edge of the accommodating cavity 215 .

[0059] The chamfered structure 217 may be an inclined arc surface formed at the edge of the first boss 213 near the accommodating cavity 215. The chamfered structure 217 is formed at the outer edge of the accommodating cavity 215 to guide the glue nail 22, so that the glue nail 22 can be easily installed in the accommodating cavity 215. During the installation process, the edge of the first boss 213 is not likely to damage the side wall of the base 221 of the glue nail 22, thereby affecting the sealing performance.

[0060] In some embodiments, please refer to Figure 5 A protrusion 216 is provided on the inner wall of the accommodating cavity 215 connected to the chamfer structure 217 . When the base 221 is installed in the accommodating cavity 215 , an outer wall of the base 221 and the protrusion 216 on the inner wall of the accommodating cavity 215 form an interference fit.

[0061] In the technical solution of the embodiment of the present application, a protrusion 216 is provided on the inner wall of the accommodating cavity 215 so that an interference fit is formed between the base 221 and the protrusion 216 at the inner wall of the accommodating cavity 215, thereby achieving a sealed connection between the base 221 of the glue nail 22 and the accommodating cavity 215 of the sealing cover 21.

[0062] In some embodiments, please refer to Figure 5 The protrusion 216 is a protruding structure with an arc, and a plurality of protrusions 216 are arranged at intervals along the inner wall of the accommodating cavity 215 and connected to the second boss 214 .

[0063] The protrusion 216 may be a curved long strip-shaped protruding structure extending along the inner wall of the accommodating cavity 215 .

[0064] In the technical solution of the embodiment of the present application, through the above-mentioned setting, the protrusion 216 with a curved protruding structure can make the outer wall of the base 221 better fit the protrusion 216, and the multiple protrusions 216 are arranged at intervals along the inner wall of the accommodating cavity 215 and connected to the second boss 214 so that the outer wall of the base 221 is sealed and connected to the accommodating cavity 215 and the second boss 214.

[0065] Second, please refer to Figure 7 and Figure 8 The present application also provides a cover plate assembly, comprising: a cover plate 1 and a sealing nail 2 as described in the first aspect, wherein a liquid injection hole 10 is provided on the cover plate 1; and the sealing nail 2 seals the liquid injection hole 10.

[0066] In the technical solution of the embodiment of the present application, the sealing pin 2 can be installed to the injection hole 10 through a feeder after formation, and the injection hole 10 and the sealing pin 2 are fixed by laser welding. When welding failure occurs at the welding part, the substance in the detection cavity 211 of the sealing pin 2 is affected by the welding heat and sublimates and flows out to the outside of the detection cavity 211, and escapes to the outside of the sealing cover 21 along the welding gap. By detecting the heated sublimated substance on the outside of the sealing pin 2, the welding state of the sealing pin can be judged, and there will be no problems of missed detection or false detection. The weld defects of the sealing pin can be reduced, and the production efficiency of the battery can be improved.

[0067] In some embodiments, please refer to Figure 7 and Figure 8 The injection hole 10 includes a first cavity 101, a second cavity 102 and a third cavity 103 which are sequentially arranged toward the inside of the cover plate 1, wherein the sealing cover 21 is welded and sealed to the first cavity 101, the first boss 213 is accommodated in the second cavity 102, and at least part of the glue nail 22 is sealed and installed in the third cavity 103.

[0068] In some embodiments, the outer diameter of the first boss 213 is smaller than the inner diameter of the second cavity 102, so that there is a gap between the outer wall of the second boss 214 and the inner wall of the second cavity 102. In some embodiments, the partial base 221 and the guide block 222 of the glue nail 22 are installed in the third cavity 103, and the partial base 221 of the glue nail 22 can be interference fit with the third cavity 103, so that the partial glue nail 22 is sealed and installed in the third cavity 103.

[0069] In the technical solution of the embodiment of the present application, at least part of the glue nail 22 is sealed and installed in the third cavity 103, so that at least part of the glue nail 22 forms a primary seal with the injection hole 10, and the sealing cover 21 is welded and sealed to the first cavity 101 so that the sealing cover 21 forms a secondary seal with the injection hole 10. Thus, the sealing nail 2 can effectively seal the injection hole 10.

[0070] Please refer to Fig. 9 The present application also provides an airtightness detection system for detecting the airtightness of the liquid injection hole in the cover assembly of the second aspect, comprising: a negative pressure exhaust device 3 for applying negative pressure to the sealed liquid injection hole 10; a detection reagent device 4 connected to the negative pressure exhaust device 3 for reacting with the heated sublimated substance to develop color; and a visual detection device 5 connected to the detection reagent device 4 for identifying the substance that reacts and develops color. In some embodiments, the visual detection device 5 can be a colorimeter.

[0071] In the technical solution of the embodiment of the present application, through the above-mentioned setting, the negative pressure exhaust device 3 can be used to exhaust negative pressure on the sealed injection hole 10. If welding failure occurs at the welding part of the sealing cover 21, the heat-sublimated substance, such as iodine vapor, can escape from the welding gap to the outside of the sealing cover 21 under the action of the negative pressure exhaust device 3, and enter the detection reagent device 4 from the negative pressure exhaust device 3. The detection reagent device 4 has a reagent or substance that can react with the heat-sublimated substance to develop color, such as starch test paper, which can react with iodine vapor to develop color. Then, the visual detection device 5 identifies and processes the substance that reacts and develops color to determine whether there is a poor weld. For example, the detection principle of starch and iodine is that starch reacts with iodine to form an inclusion compound. Within a certain range of starch polymerization degree or relative molecular mass, as the starch polymerization degree or relative molecular mass increases, the color of the inclusion compound changes from colorless, orange, light red, purple to blue. For example, the reaction process of amylose is as follows: nI2+(C6H 10 O5)6n=(C 18 H 30 O5I)2n.

[0072] In addition, the glue nail 22 of the embodiment of the present application is installed integrally with the sealing cover 21 to form a sealing nail 2. After the sealing nail 2 is formed, the sealing is tested by detecting the thermal sublimation iodine reagent. This can eliminate the need for negative pressure helium injection in advance in the existing process and the need to install the glue nail and the sealing cover in two steps. The simplified operating procedures can achieve the purpose of fewer weld defects and high production efficiency.

[0073] On the other hand, the present application also provides a battery, comprising the cover plate assembly described in the second aspect.

[0074] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A sealing nail, characterized in that: include: A sealing cover (21), comprising a detection cavity (211) and a notch (212) for penetrating the inside and outside of the detection cavity (211); as well as, A glue nail (22), at least a portion of the glue nail (22) is sealed and connected to one side of the sealing cover (21), so as to form the detection cavity (211) therebetween.

2. The sealing nail according to claim 1, characterized in that: A first boss (213) is provided on a side of the sealing cover (21) facing the glue nail (22), a cavity (210) is formed inside the first boss (213), a second boss (214) is provided in the cavity (210) on a side close to the sealing cover (21), the detection cavity (211) is formed in the second boss (214), and a receiving cavity (215) is formed in the cavity (210) and on a side of the second boss (214) away from the sealing cover (21), and at least a portion of the glue nail (22) is sealedly connected to the receiving cavity (215) and the second boss (214).

3. The sealing nail according to claim 2, characterized in that: The notch (212) is extended from the second boss (214) to the first boss (213) along the radial direction of the sealing cover (21), so that the notch (212) passes through the inside and outside of the detection cavity (211).

4. The sealing nail according to claim 1, characterized in that: The inner surface of the detection cavity (211) is coated with a substance that sublimates when heated, and the notch (212) allows the substance to flow out from the inside of the detection cavity (211) to the outside after being sublimated when heated.

5. The sealing nail according to claim 2, characterized in that: The plastic nail (22) comprises: A base (221), at least a portion of the base (221) forms an interference fit with the accommodating cavity (215) and the second boss (214); A guide block (222) is connected to the base (221) and is located on a side away from the sealing cover (21). At least one plane (223) is provided on an outer side wall of the guide block (222), and the plane (223) is extended along the axial direction of the guide block (222).

6. The sealing nail according to claim 5, characterized in that: The first boss (213) is formed with a chamfered structure (217) at the outer edge of the accommodating cavity (215); a protrusion (216) is provided at the inner wall of the accommodating cavity (215) connected to the chamfered structure (217); when the base (221) is installed in the accommodating cavity (215), the outer wall of the base (221) and the protrusion (216) at the inner wall of the accommodating cavity (215) form an interference fit.

7. The sealing nail according to claim 6, characterized in that: The protrusion (216) is a protruding structure with an arc, and a plurality of the protrusions (216) are arranged at intervals along the inner wall of the accommodating cavity (215) and are connected to the second boss (214).

8. A cover plate assembly, characterized in that: include: A cover plate (1), wherein the cover plate (1) is provided with a liquid injection hole (10); as well as, The sealing nail (2) according to any one of claims 1 to 7, wherein the sealing nail (2) seals the liquid injection hole (10).

9. The cover plate assembly according to claim 8, characterized in that: The injection hole (10) comprises a first cavity (101), a second cavity (102) and a third cavity (103) which are sequentially arranged toward the inside of the cover plate (1), wherein the sealing cover (21) is welded and sealed to the first cavity (101), the first boss (213) is accommodated in the second cavity (102), and at least a part of the glue nail (22) is sealed and installed in the third cavity (103).

10. A battery, characterized in that: Comprising the cover plate assembly according to claim 8 or 9.

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