Cover plate assembly and battery cell

Abstract

The application relates to the technical field of lithium battery production, and provides a cover plate assembly and a battery cell. The cover plate assembly comprises a cover plate body provided with a liquid injection hole, a sealing cover and a sealing plug. The liquid injection hole is provided with a first hole and a second hole which are communicated along a liquid injection direction, the aperture of the first hole is larger than that of the second hole; the sealing cover is arranged in the first hole and is welded to the cover plate body, and a gas flow space is formed between the sealing cover and the sealing plug; the sealing plug is in interference fit in the second hole, one end of the sealing plug is provided with a gas storage cavity used for storing detection gas, and under a preset condition, the gas storage cavity can be communicated with the gas flow space to release the detection gas. The cover plate assembly can utilize the detection gas sealed in the sealing plug and the gas flow space formed between the sealing cover and the sealing plug to detect the sealing effect between the sealing cover and the cover plate body, and can avoid the problem that the sealing between the sealing plug and the second hole affects the detection reliability.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to a cover plate assembly. This application also relates to a battery cell equipped with the aforementioned cover plate assembly. Background Technology

[0002] In lithium battery structures, an injection hole is typically provided on the cover plate for injecting electrolyte. After the electrolyte injection, formation, and possible replenishment operations are completed, the injection hole is generally sealed using a sealing plug and a sealing cap. After the sealing plug is inserted into the injection hole, the sealing cap is assembled with the cover plate and laser welded to achieve a sealing effect for the entire structure.

[0003] To test the welding effect of the sealing cap and the cover plate, helium testing and other methods are usually used to inspect the sealing performance of the weld. However, due to the interference fit between the sealing plug and the injection hole, it may be impossible to effectively test the sealing effect between the sealing cap and the cover plate. Utility Model Content

[0004] In view of this, the present application aims to provide a cover assembly that can effectively detect the sealing effect between the sealing cover and the cover body.

[0005] To achieve the above objectives, the technical solution of this application is implemented as follows: A cover plate assembly includes a cover plate body having an injection hole, a sealing cap, and a sealing plug; The injection hole has a first hole and a second hole that are connected along the injection direction. The diameter of the first hole is larger than the diameter of the second hole, and a stepped surface is formed between the first hole and the second hole. The sealing cap is disposed in the first hole and welded to the cover plate body, and a gas flow space is formed between the sealing cap and the sealing plug; The sealing plug is interference-fitted into the second hole. One end of the sealing plug near the sealing cap is provided with a gas storage chamber for storing the detection gas. Under preset conditions, the gas storage chamber can communicate with the gas flow space to release the detection gas.

[0006] Furthermore, the end of the sealing plug is formed with a groove that is recessed into the interior of the sealing plug, and a patch is provided at the opening of the groove to seal the opening. The groove and the patch together form the gas storage cavity.

[0007] Furthermore, the patch includes a main body and an adhesive layer disposed on one side of the main body; the adhesive layer is arranged in a ring around the circumference of the groove, and the patch is bonded to the edge of the groove by the adhesive layer.

[0008] Furthermore, the main body is made of PC, PET or PE; and / or, the adhesive layer is made of pressure-sensitive adhesive.

[0009] Furthermore, the thickness D1 of the main body is between 0.1 mm and 0.3 mm; and / or the thickness D2 of the adhesive layer is between 0.05 mm and 0.2 mm.

[0010] Furthermore, in the longitudinal section of the second hole, the width D of the adhesive layer is greater than the overlap distance L between the adhesive layer and the edge of the groove.

[0011] Furthermore, the sealing cap has a cap body covering the sealing plug, a buffer portion circumferentially disposed on the cap body, and a weld portion circumferentially disposed on the buffer portion; the weld portion is interference-fitted with the sidewall of the first hole.

[0012] Furthermore, the sealing plug includes a rubber plug body and an overlapping edge disposed at the end of the rubber plug body; the rubber plug body is interference-fitted in the second hole, the overlapping edge overlaps the stepped surface, and the gas storage cavity is disposed on the rubber plug body.

[0013] Furthermore, a limiting portion is provided at one end of the rubber stopper body away from the overlapping edge; the limiting portion can abut against one side of the cover plate body and is used to limit the position of the rubber stopper body in the second hole.

[0014] Compared with related technologies, this application has the following advantages: (1) The cover plate assembly described in this application, by setting the sealing cover in the first hole of the injection hole and the sealing plug in the second hole of the injection hole, makes the sealing cover and the cover plate body welded together, and the sealing plug is provided with a gas storage chamber for storing detection gas. At the same time, a gas flow space is formed between the sealing cover and the sealing plug. In this way, under preset conditions, such as when performing helium detection under negative pressure, the detection gas in the gas storage chamber can be released into the gas flow space. When there are problems such as welding explosions or missing welds between the sealing cover and the cover plate, the detection gas flows out through the welding explosions or missing welds. This can avoid the sealing problem between the sealing cover and the cover plate being unable to be detected due to the sealing between the sealing plug and the second hole. Thus, it can effectively detect the welding quality of the sealing cover and the cover plate body, improve the accuracy of the sealing detection of the welding position of the sealing cover and the cover plate body, and has a good use effect.

[0015] (2) A groove is set at the end of the sealing plug, which is combined with a patch that is sealed at the groove opening to form a gas storage cavity. This structure is easy to process and prepare, and under preset conditions, the detection gas can be released by utilizing the failure of the seal between the patch and the groove opening.

[0016] (3) The patch includes a main body and an adhesive layer, such that the adhesive layer is arranged in a ring around the circumference of the groove. This allows the patch to be bonded to the edge of the groove using the adhesive layer, thus achieving bonding between the patch and the edge of the groove. This facilitates the preparation of the gas storage cavity and ensures the sealing of the gas storage cavity.

[0017] (4) The patch is made of PC, PET or PE, which gives it excellent mechanical properties, makes it less prone to tearing, and also provides good chemical resistance. The adhesive layer is made of pressure-sensitive adhesive, which ensures good adhesion and also facilitates reliable peeling under preset conditions.

[0018] (5) Limiting the thickness of the main body not only avoids affecting the sealing of the groove due to insufficient thickness, but also avoids affecting the peeling effect due to excessive thickness and excessive patch weight, thus achieving better compatibility between the sealing of the groove and the peeling effect. Limiting the thickness of the adhesive layer can ensure compatibility between the reliability of the main body bonding and the peeling effect of the main body.

[0019] (6) Set the width of the adhesive layer to be greater than the overlap distance between the adhesive layer and the edge of the groove. This can avoid the main body from being unable to bond well with the edge of the groove due to assembly errors, thereby ensuring the reliability of the bonding between the main body and the edge of the groove.

[0020] (7) The sealing cover has a cover body, a buffer part and a welding part, and the welding part is interference fit with the side wall of the first hole. On the one hand, the interference fit between the welding part and the side wall of the first hole can make the contact between the sealing cover and the cover plate body tighter, which is conducive to ensuring the assembly position and welding quality of the sealing cover. On the other hand, the buffer part can prevent the weld from cracking due to thermal expansion and contraction when the sealing cover is welded to the cover plate body.

[0021] (8) The sealing plug includes a rubber plug body and an overlapping edge at the end of the rubber plug body, so that the overlapping edge overlaps on the step surface, which can play a certain limiting role in the installation of the sealing plug and ensure the installation position of the sealing plug.

[0022] (9) A limiting part is provided at the end of the rubber plug body away from the overlapping edge, which can further ensure the installation position of the rubber plug body in the second hole, and effectively prevent the rubber plug body from coming out of the cover plate body along the second hole when the internal pressure of the battery cell is too high.

[0023] This application also proposes a battery cell having a cover plate assembly as described above.

[0024] The battery cell described in this application, by utilizing the aforementioned cover plate assembly, can release detection gas from the gas storage chamber into the gas flow space when there are problems such as welding craters or missing welds between the sealing cap and the cover plate. The gas then flows out through the welding craters or missing welds, thereby avoiding the inability to detect sealing problems between the sealing cap and the cover plate due to the sealing between the sealing plug and the second hole. This effectively detects the welding quality between the sealing cap and the cover plate body, thus improving the yield rate of battery cell manufacturing. 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 a structural schematic diagram of the cover plate assembly in application state according to an embodiment of this application; Figure 2 This is an exploded view of the application state of the cover plate assembly described in the embodiments of this application; Figure 3 This is a schematic diagram of the cover plate assembly described in an embodiment of this application; Figure 4 for Figure 3 Sectional view from the AA direction; Figure 5 This is a partial structural diagram of the cover plate body described in an embodiment of this application; Figure 6 This is a perspective view of the sealing plug described in the embodiments of this application; Figure 7 This is a cross-sectional view of the sealing plug described in an embodiment of this application; Figure 8 This is a schematic diagram of the sealing cap structure described in an embodiment of this application; Figure 9 This is a schematic diagram of another structure of the sealing plug described in the embodiments of this application; Explanation of reference numerals in the attached figures: 1. Cover plate body; 2. Lower housing; 3. Sealing plug; 4. Sealing cover; 11. Positive terminal; 12. Negative terminal; 13. Explosion-proof valve; 31. Patch; 100. Injection port; 101. First hole; 102. Second hole; 301. Rubber stopper body; 302. Overlapping edge; 303. Limiting part; 311. Main body; 312. Adhesive layer; 401. Cap body; 402. Buffer part; 403. Welding part; 10. Gas storage chamber; 20. Gas flow space. Detailed Implementation

[0026] 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.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] An embodiment of the first aspect of this application provides a cover plate assembly that, through structural optimization, can effectively detect the sealing effect between the sealing cap and the cover plate body.

[0033] In related technologies, lithium battery structures typically include an injection hole on the cover plate for injecting electrolyte. After electrolyte injection, formation, and possible replenishment, the injection hole is usually sealed using a sealing plug and a sealing cap. After the sealing plug is inserted into the injection hole, the sealing cap is assembled with the cover plate and laser-welded to achieve a sealed effect for the entire structure.

[0034] To test the welding effect of the sealing cap and the cover plate, a negative pressure helium test is usually used to check the sealing performance of the weld. However, due to the interference fit between the sealing plug and the injection hole, it may be impossible to effectively test the sealing effect between the sealing cap and the cover plate, thus affecting the accuracy of the test results.

[0035] In view of this, in order to overcome the shortcomings of the related technology, the battery cell assembly in this embodiment combines... Figures 1 to 9 As shown, the overall design includes a cover body 1 with an injection hole 100, a sealing cap 4, and a sealing plug 3.

[0036] The injection hole 100 has a first hole 101 and a second hole 102 connected along the injection direction. The diameter of the first hole 101 is larger than the diameter of the second hole 102, and a stepped surface is formed between the first hole 101 and the second hole 102. The sealing cap 4 is disposed in the first hole 101 and welded to the cover plate body 1, and a gas flow space 20 is formed between the sealing cap 4 and the sealing plug 3. The sealing plug 3 is interference-fitted into the second hole 102, and a gas storage chamber 10 for storing detection gas is provided at the end of the sealing plug 3 near the sealing cap 4. Under preset conditions, the gas storage chamber 10 can communicate with the gas flow space 20 to release the detection gas.

[0037] Therefore, by placing the sealing cap 4 in the first hole 101 of the injection hole 100 and the sealing plug 3 in the second hole 102 of the injection hole 100, the sealing cap 4 is welded to the cover plate body 1. The sealing plug 3 is provided with a gas storage chamber 10 for storing detection gas. At the same time, a gas flow space 20 is formed between the sealing cap 4 and the sealing plug 3. Under preset conditions, such as helium detection under negative pressure, the detection gas in the gas storage chamber 10 can be released into the gas flow space 20. When there are problems such as welding craters or missing welds between the sealing cap 4 and the cover plate, the detection gas is released into the gas flow chamber and flows out through the welding craters or missing welds. This can avoid the sealing problem between the sealing cap 4 and the cover plate being unable to be detected due to the sealing between the sealing plug 3 and the second hole 102. Thus, the welding quality of the sealing cap 4 and the cover plate body 1 can be effectively detected, and the accuracy of the sealing test at the welding position can be improved.

[0038] Based on the above overview, specifically, refer to Figures 1 to 4As shown, in the cell structure, a cover assembly is disposed on the lower housing 2 of the cell. The cover assembly includes a cover body 1 with an injection hole 100, a lower plastic component, a positive terminal 11 and a negative terminal 12, an explosion-proof valve 13, a sealing cap 4, and a sealing plug 3, etc., located on one side of the cover body 1. The lower plastic component mainly serves as electrical insulation. The positive terminal 11 and the negative terminal 12 are used for electrical connection with the corresponding positive and negative tabs in the electrode assembly inside the lower housing 2. The injection hole 100 is used to inject electrolyte into the lower housing 2.

[0039] In this embodiment, the injection hole 100 has a first hole 101 and a second hole 102 connected together. Along the injection direction, the diameter of the first hole 101 is larger than the diameter of the second hole 102. A sealing cap 4 is disposed in the first hole 101, and its material is preferably the same as that of the cover plate body 1, such as aluminum or aluminum alloy. The sealing cap 4 is welded to the cover plate body 1. A sealing plug 3 is interference-fitted into the second hole 102. The distance between the sealing cap 4 and the sealing plug 3 is set to form a gas flow space 20.

[0040] In this embodiment, the sealing plug 3 is made of elastic material, and the end of the sealing plug 3 near the sealing cover 4 is provided with a gas storage chamber 10 for storing detection gas. Under preset conditions, the gas storage chamber 10 can be connected to the gas flow space 20. At this time, the detection gas in the gas storage chamber 10 is released and flows out through the flow space and the welding explosion point or the missing weld position.

[0041] Continue to combine Figures 4 to 7 As shown, in some exemplary embodiments, a groove recessed into the sealing plug 3 is formed at the end of the sealing plug 3, and a patch 31 is provided at the opening of the groove to seal the groove, thereby forming a gas storage cavity 10 by the groove and the patch 31. In this structure, by using a groove provided at the end of the sealing plug 3 to cooperate with the patch 31 sealing the opening of the groove to form a gas storage cavity 10, the gas storage cavity 10 is facilitated in its fabrication, and under preset conditions, the detection gas can be released by the failure of the seal between the patch 31 and the groove opening.

[0042] It should be noted that the detection gas mentioned above is an inert gas, such as helium or nitrogen, with helium being preferred. The preset conditions mentioned above specifically refer to the condition where, during helium testing, the welding area between the sealing cap 4 and the cover plate body 1 is under negative pressure, and the seal between the patch 31 and the groove edge fails. The helium testing pressure can be set according to the actual product process requirements. Under this pressure, when there is a leak between the sealing cap 4 and the cover plate body 1, the patch 31 can be reliably peeled off from the groove edge, allowing the gas storage chamber 10 to connect with the gas flow space 20. The detection gas in the gas storage chamber 10 is released and escapes from the leak location through the gas flow space 20. This determines that the weld between the sealing cap 4 and the cover plate body 1 is faulty.

[0043] Reference Figure 7 As shown, in some exemplary embodiments, the patch 31 includes, for example, a main body 311 and an adhesive layer 312 disposed on one side of the main body 311. The adhesive layer 312 is arranged in a ring around the circumference of the groove, and the patch 31 is bonded to the edge of the groove through the adhesive layer 312. This allows the patch 31 to be bonded to the edge of the groove using the adhesive layer 312, achieving an adhesive connection between the patch 31 and the edge of the groove, thereby facilitating the fabrication of the gas storage cavity 10 and ensuring the airtightness of the gas storage cavity 10.

[0044] In some exemplary embodiments, the main body 311 is made of, for example, PC, PET, or PE. This material gives the patch 31 excellent mechanical properties, making it less prone to tearing and providing good chemical resistance. Furthermore, the adhesive layer 312 is made of, for example, pressure-sensitive adhesive, ensuring good adhesion while also facilitating reliable peeling under predetermined conditions. It is worth noting that the peel strength of the adhesive layer 312 can be, for example, between 15 N / in and 20 N / in, thus ensuring both the adhesion between the patch 31 and the main body 311 and reliable peeling under negative pressure helium detection.

[0045] Continue to refer to Figure 7 As shown, in some exemplary embodiments, the thickness D1 of the main body 311 is, for example, between 0.1 mm and 0.3 mm. In specific implementations, the thickness D1 of the main body 311 can be set to, for example, 0.1 mm, 0.2 mm, 0.3 mm, etc. Limiting the thickness of the main body 311 here not only avoids affecting the sealing of the groove due to excessive thickness, but also avoids affecting the peeling effect due to excessive thickness causing a large weight of the patch 31, thus achieving better compatibility between the sealing of the groove and the peeling effect.

[0046] Furthermore, in some exemplary embodiments, the thickness D2 of the adhesive layer 312 is, for example, between 0.05 and 0.2 mm. In specific implementations, the thickness D2 of the adhesive layer 312 can be set to, for example, 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.18 mm, or 0.2 mm. Limiting the thickness of the adhesive layer 312 here allows for a balance between the reliability of the bonding of the main body 311 and the effectiveness of peeling off the main body 311.

[0047] Still refer to Figure 7 As shown, in some exemplary embodiments, in the longitudinal section of the second hole 102, the width D of the adhesive layer 312 is greater than the overlap distance L between the adhesive layer 312 and the groove edge. This avoids the inability of a portion of the main body 311 to bond well with the groove edge due to assembly errors, thereby ensuring the reliability of the bonding between the main body 311 and the groove edge.

[0048] Combination Figure 4 and Figure 8 As shown, in some exemplary embodiments, the sealing cap 4 has a cap body 401 covering the sealing plug 3, a buffer portion 402 circumferentially disposed on the cap body 401, and a weld portion 403 circumferentially disposed on the buffer portion 402. The weld portion 403 is interference-fitted with the sidewall of the first hole 101.

[0049] In terms of specific structure, the cover body 401 is a flat plate shape, and the buffer part 402 includes a buffer groove formed on the circumference of the cover body 401, which is located on one side of the cover body 401. The side wall of the first hole 101 is inclined, and the welding part 403 is disposed on the circumference of the buffer part 402, that is, on the outer circumferential surface of the buffer groove. The welding part 403 is interference-fitted into the first hole 101, and the outer side surface of the cover body 401 is flush with the outer side surface of the cover plate body 1 as much as possible to ensure the overall appearance quality of the battery cell.

[0050] In the above structure, the sealing cover 4 has a cover body 401, a buffer part 402, and a welding part 403, and the welding part 403 is interference-fitted with the side wall of the first hole 101. This not only makes the contact between the sealing cover 4 and the cover plate body 1 tighter by utilizing the interference fit between the welding part 403 and the side wall of the first hole 101, but also helps to ensure the assembly position and welding quality of the sealing cover 4. At the same time, the buffer part 402 can also prevent the weld from cracking due to thermal expansion and contraction when the sealing cover 4 is welded to the cover plate body 1.

[0051] See Figures 4 to 7As shown, in some exemplary embodiments, the sealing plug 3 includes, for example, a rubber plug body 301 and an overlapping edge 302 located at the end of the rubber plug body 301. The rubber plug body 301 is interference-fitted into the second hole 102, meaning the periphery of the rubber plug body 301 is interference-fitted with the inner wall of the second hole 102. The overlapping edge 302 specifically overlaps the stepped surface, and this overlapping edge 302 can limit the installation of the sealing plug 3, ensuring the installation position of the sealing plug 3. The aforementioned air storage cavity 10 is located on the rubber plug body 301. Specifically, a groove is formed at the end of the rubber plug body 301 near the sealing cap 4, and a patch 31 is adhered to the rubber plug body 301, sealing the opening of the groove.

[0052] Reference Figure 9 As shown, in some exemplary embodiments, a limiting portion 303 is provided at one end of the rubber stopper body 301 away from the overlapping edge 302. This limiting portion 303 can abut against one side of the cover plate body 1 and is used to limit the position of the rubber stopper body 301 in the second hole 102. At this time, by using the limiting portion 303, the installation position of the rubber stopper body 301 in the second hole 102 can be further guaranteed, and when the internal pressure of the battery cell is too high, the rubber stopper body 301 can be effectively prevented from coming out of the cover plate body 1 along the second hole 102.

[0053] It is worth noting that a helium-absorbing material can also be incorporated into the sealing plug 3 to give it a strong helium adsorption capacity. For example, the helium-absorbing material can be incorporated into the matrix of the sealing plug 3. The matrix may include at least one of polyphenylene sulfide, polyethylene terephthalate, acrylonitrile-butadiene-styrene, polycarbonate, polyamide, polybutylene terephthalate, polyoxymethylene, and polyphenylene ether. Therefore, the sealing component has better performance, is easy to process, uses widely available materials, and has a lower cost.

[0054] The helium-absorbing material can include at least one of activated carbon powder, alumina powder, and silica powder. This results in superior helium absorption performance, good compatibility with the matrix, and a wide availability and low cost. Therefore, even if the helium gas encapsulated within the sealing plug 3 fails or leaks, the sealing plug 3 can still absorb helium, allowing for detection during backpressure helium testing and thus improving the accuracy of the seal test.

[0055] In this embodiment, it is worth noting that the detection gas, such as helium, needs to be pre-encapsulated in the gas storage chamber 10. During helium encapsulation, for example in a vacuum environment, helium is injected into the groove, and then the helium is encapsulated in the groove using the patch 31, thereby forming a helium-encapsulated sealing plug 3. Then, the helium-encapsulated sealing plug 3 is press-fitted into the second hole 102, and the sealing cap 4 is assembled into the first hole 101. Next, the sealing cap 4 is welded to the cover plate body 1, completing the assembly of the cover plate assembly.

[0056] During helium testing, a helium detector is attached to the injection hole 100, covering the welded area, and then a vacuum is applied to test the sealing performance between the sealing cap 4 and the cover plate body 1. When the weld between the sealing cap 4 and the cover plate body 1 is poor, with weld spalls or leaks, negative pressure will enter the battery through the weld spalls or leaks. The negative pressure will adsorb and peel off the patch 31, causing the adhesion between the patch 31 and the sealing plug 3 to fail. Helium gas in the groove at the end of the sealing plug 3 will be released and flow out through the gas flow space 20 and the defective locations such as weld spalls, thus detecting welding quality problems.

[0057] It is worth noting that, regarding the cover plate assembly of this embodiment, based on the above exemplary embodiments, in specific implementation, as a preferred embodiment, it is still composed of... Figures 1 to 9 As shown, it includes a cover plate body 1, a sealing cap 4 and a sealing plug 3. The cover plate body 1 has an injection hole 100. The injection hole 100 has a first hole 101 and a second hole 102 connected together. Along the injection direction, the diameter of the first hole 101 is larger than the diameter of the second hole 102, and a stepped surface is formed between the first hole 101 and the second hole 102.

[0058] A sealing cap 4 is disposed in the first hole 101 and welded to the cover plate body 1. A gap is provided between the sealing cap 4 and the sealing plug 3, forming a gas flow space 20. The sealing plug 3 is interference-fitted into the second hole 102, and a gas storage chamber 10 for storing detection gas is provided at the end of the sealing plug 3 near the sealing cap 4. Under preset conditions, the gas storage chamber 10 can communicate with the gas flow space 20 to release detection gas for testing the sealing performance of the weld between the sealing cap 4 and the cover plate body 1.

[0059] The sealing plug 3 has a groove at its end that is recessed into the interior of the sealing plug 3, and a patch 31 is provided at the opening of the groove to seal the opening. The groove and the patch 31 together form a gas storage cavity 10.

[0060] The sealing cap 4 has a cap body 401 covering the sealing plug 3, a buffer portion 402 circumferentially disposed on the cap body 401, and a welding portion 403 circumferentially disposed on the buffer portion 402. The welding portion 403 is interference-fitted with the side wall of the first hole 101.

[0061] The sealing plug 3 includes a rubber plug body 301 and an overlapping edge 302 disposed at the end of the rubber plug body 301. The rubber plug body 301 is interference-fitted in the second hole 102, and the overlapping edge 302 overlaps on the stepped surface. The air storage cavity 10 is disposed on the rubber plug body 301.

[0062] A limiting part 303 may also be provided at one end of the rubber stopper body 301 away from the overlapping edge 302. The limiting part 303 can abut against one side of the cover plate body 1 and is used to limit the position of the rubber stopper body 301 in the second hole 102.

[0063] In the above preferred embodiments, the structure, material, and thickness of each part of the patch 31, as well as the specific setting and arrangement of the sealing plug 3 and the sealing cap 4, can still be referred to the descriptions in the above exemplary embodiments. Furthermore, in this preferred embodiment, the beneficial effects brought about by the design of the patch 31, material, and thickness of each part, as well as the sealing plug 3 and the sealing cap 4, can also be referred to the descriptions in the above exemplary embodiments.

[0064] The cover plate assembly of this embodiment adopts the above design. By setting a sealing plug 3 containing detection gas and a gas flow space 20 formed between the sealing cover 4 and the sealing plug 3, when detecting the weld seal between the sealing cover 4 and the cover plate, if there are defects such as weld spatters or incomplete welds, the detection gas in the gas storage chamber 10 is released into the gas flow space 20 and flows out through the weld spatters or incomplete welds. This avoids the inability to detect the seal problem between the sealing cover 4 and the cover plate due to the seal between the sealing plug 3 and the second hole 102, thereby effectively detecting the welding quality of the sealing cover 4 and the cover plate body 1 and improving the accuracy of the detection.

[0065] An embodiment of the second aspect of this application provides a battery cell, such as Figure 1 and Figure 2 As shown, the battery cell has a cover plate assembly as described above.

[0066] In this embodiment, the battery cell, by adopting the cover plate assembly as described above, can release the detection gas in the gas storage chamber 10 into the gas flow space 20 when there are problems such as welding craters or missing welds between the sealing cover 4 and the cover plate, and flow out through the welding craters or missing welds. This can avoid the inability to detect the sealing problem between the sealing cover 4 and the cover plate due to the sealing between the sealing plug 3 and the second hole 102, thereby effectively detecting the welding quality between the sealing cover 4 and the cover plate body 1, which is conducive to improving the yield of battery cell manufacturing.

[0067] 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 cover plate assembly, characterized in that: Includes a cover body with an injection hole, as well as a sealing cap and a sealing plug; The injection hole has a first hole and a second hole that are connected along the injection direction. The diameter of the first hole is larger than the diameter of the second hole, and a stepped surface is formed between the first hole and the second hole. The sealing cap is disposed in the first hole and welded to the cover plate body, and a gas flow space is formed between the sealing cap and the sealing plug; The sealing plug is interference-fitted into the second hole. One end of the sealing plug near the sealing cap is provided with a gas storage chamber for storing the detection gas. Under preset conditions, the gas storage chamber can communicate with the gas flow space to release the detection gas.

2. The cover plate assembly according to claim 1, characterized in that: The end of the sealing plug has a groove that is recessed into the interior of the sealing plug, and a patch is provided at the opening of the groove to seal the opening. The groove and the patch together form the gas storage cavity.

3. The cover plate assembly according to claim 2, characterized in that: The patch includes a main body and an adhesive layer disposed on one side of the main body; The adhesive layer is arranged in a ring around the circumference of the groove, and the patch is bonded to the edge of the groove through the adhesive layer.

4. The cover plate assembly according to claim 3, characterized in that: The main body is made of PC, PET or PE; and / or the adhesive layer is made of pressure-sensitive adhesive.

5. The cover plate assembly according to claim 3, characterized in that: The thickness D1 of the main body is between 0.1 mm and 0.3 mm; and / or the thickness D2 of the adhesive layer is between 0.05 mm and 0.2 mm.

6. The cover plate assembly according to claim 3, characterized in that: In the longitudinal section of the second hole, the width D of the adhesive layer is greater than the overlap distance L between the adhesive layer and the edge of the groove.

7. The cover plate assembly according to claim 1, characterized in that: The sealing cap has a cap body covering the sealing plug, a buffer portion circumferentially disposed on the cap body, and a weld portion circumferentially disposed on the buffer portion; The welded part is interference-fitted with the sidewall of the first hole.

8. The cover plate assembly according to any one of claims 1 to 7, characterized in that: The sealing plug includes a rubber plug body and an overlapping edge disposed at the end of the rubber plug body; The rubber stopper body is interference-fitted into the second hole, the overlapping edge overlaps the stepped surface, and the air storage cavity is located on the rubber stopper body.

9. The cover plate assembly according to claim 8, characterized in that: The end of the rubber stopper body away from the overlapping edge is provided with a limiting part; The limiting part can abut against one side of the cover plate body and is used to limit the position of the rubber stopper body in the second hole.

10. A battery cell, characterized in that: The battery cell is provided with a cover plate assembly as described in any one of claims 1 to 9.

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