Air tightness detection device and air tightness detection method

Abstract

The invention provides an air tightness detection device and an air tightness detection method, and relates to the technical field of sealing performance of batteries. The air tightness detection device comprises an outer cavity sleeve and an inner pressing shaft, the outer cavity sleeve is provided with a movable hole, and the inner pressing shaft penetrates through the movable hole and can move along the movable hole; the outer cavity sleeve is provided with a first sealing end, the first sealing end is configured to abut against the cover plate, so that a detection cavity is defined between the inner wall of the movable hole and the cover plate, and the sealing opening is located in the detection cavity; when air tightness detection is carried out, the detection cavity can be vacuumized and detection gas can be pressed into the detection cavity. The inner pressing shaft is provided with a second sealing end, and when the detection gas in the detection cavity is pumped away, the second sealing end abuts against the sealing opening. According to the system, vacuumizing, helium pressing and helium detection can be achieved at the same time through a single set of system, the structure is simple, cost is low, the sealing problem existing in the switching process can be avoided, detection gas in the detection cavity is prevented from being pumped away when a large leakage opening is formed, large leakage detection is achieved, false detection is avoided, and the detection precision is improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery sealing detection, and in particular to an airtightness detection device and an airtightness detection method. Background Art

[0002] The main function of the battery shell is to protect the materials inside the battery. The battery shell is generally formed by bending and welding aluminum plates. Due to the thin thickness of the aluminum plate, air leakage may occur at the weld. After the shell is welded, it needs to be tested for sealing.

[0003] In order to improve the detection efficiency and accuracy, helium is used to detect welds. In related technologies, helium detection mechanisms generally use a double-head back pressure method for helium detection (helium pressure head and helium detection head), with two independent pipeline systems. Specific operation process: First, the helium pressure head presses helium into the sealed cavity after welding, maintains the pressure for a period of time and then withdraws, and then the helium detection head presses down to vacuum and detect helium.

[0004] However, the above detection device has no large leak detection function, is costly, and requires complex maintenance. Moreover, if there is a large leak, helium will be directly extracted during vacuuming, which may easily lead to false detection and poor detection accuracy. Summary of the invention

[0005] In view of the above problems, the embodiments of the present application provide an airtightness detection device and an airtightness detection method, which can simultaneously realize vacuum extraction, helium compression and helium detection using a single system. It has a simple structure and low cost, and helps to avoid sealing problems in the switching process, thereby preventing the detection gas inside the detection chamber from being drawn away when a large leak occurs, thereby realizing the detection of large leaks, avoiding false detections, and improving detection accuracy.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A first aspect of an embodiment of the present application provides an airtightness detection device for detecting the airtightness of a cavity, wherein the cover plate of the cavity has a sealing port; the airtightness detection device comprises an outer cavity sleeve and an inner pressure shaft, wherein the outer cavity sleeve has a movable hole, and the inner pressure shaft is passed through the movable hole and can move along the movable hole; the outer cavity sleeve has a first sealing end, and the first sealing end is configured to abut against the cover plate, so that a detection cavity is formed between the inner wall of the movable hole and the cover plate, and the sealing port is located in the detection cavity; when performing an airtightness detection, the detection cavity can be evacuated and detection gas can be pressed into it; the inner pressure shaft has a second sealing end, and when the detection gas in the detection cavity is evacuated, the second sealing end abuts against the sealing port.

[0008] In a feasible implementation, the first sealing end is arranged around the axial end of the movable hole, and the first sealing end covers the sealing port in an area surrounded by the axial projection of the movable hole.

[0009] In a feasible implementation, a cavity is provided at one end of the inner pressure shaft facing the cover plate, and the second sealing end is arranged around the circumferential edge of the cavity; the contour shape of the second sealing end matches the contour shape of the sealing port.

[0010] In a feasible implementation, a side wall of the inner pressure shaft is provided with a connecting hole, and the connecting hole connects the cavity with the outer side of the inner pressure shaft.

[0011] In one feasible embodiment, the side wall of the outer cavity sleeve is connected to a ventilation joint, and the ventilation joint is connected to the detection cavity; the ventilation joint is configured to be connected to any one of a vacuum pump, an air filling tank, and a leak detector; the connecting hole is arranged opposite to the ventilation joint.

[0012] In a feasible implementation, the first sealing end is provided with a first sealing member, and the first sealing member abuts between the outer cavity sleeve and the cover plate.

[0013] In an achievable implementation, the second sealing end is provided with a second sealing member, and the second sealing member abuts against a circumferential edge of the sealing port.

[0014] In a feasible implementation, the outer wall of the inner pressure shaft is provided with a sealing groove surrounding the circumference thereof, a sealing ring is provided in the sealing groove, and the sealing ring at least partially protrudes out of the sealing groove and abuts against the inner wall of the movable hole.

[0015] In a feasible embodiment, the airtightness detection device is configured to detect the airtightness of the battery pack cavity, the sealing port of the cover plate is welded and sealed to form an annular weld surrounding the sealing port; when the air is evacuated from the detection cavity and the detection gas is pressed into the detection cavity, the second sealing end is separated from the annular weld; when the detection gas is evacuated from the detection cavity, the second sealing end abuts against the annular weld.

[0016] The second aspect of the embodiment of the present application provides an airtightness detection method for use in an airtightness detection device; the method comprises: driving the outer cavity sleeve downward to abut against the surface of the cover plate so that the circumferential outer side of the sealing port of the cover plate is sealed, and the outer cavity sleeve and the cover plate are surrounded to form a detection cavity; connecting the vacuum pump with the detection cavity, and evacuating the detection cavity to a first preset pressure value; connecting the air filling tank with the detection cavity, and filling the detection cavity with detection gas to a second preset pressure value; after driving the inner pressure shaft downward to seal the sealing port, connecting the vacuum pump with the detection cavity, and evacuating the detection cavity to a third preset pressure value; driving the inner pressure shaft to reset, and connecting the leak detector with the detection cavity to detect the airtightness of the sealing port.

[0017] The embodiment of the present application provides an airtightness detection device and an airtightness detection method, including an outer cavity sleeve and an inner pressure shaft. On the one hand, a single system can be used to simultaneously realize vacuuming, helium compression and helium detection, which has a simple structure and reduces costs, and helps to avoid sealing problems in the switching process, thereby avoiding the detection gas inside the detection cavity from being drawn away when there is a large leak, realizing the detection of large leaks and avoiding false detections; on the other hand, the design of the inner pressure shaft helps to control the free state of helium during vacuuming, and the detection structure is more real and effective, and can simplify the entire detection logic and maximize the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the coordinated detection structure of the airtightness detection device and the battery provided in the embodiment of the present application;

[0019] Figure 2 A schematic diagram of the structure of an annular weld of a battery provided in an embodiment of the present application;

[0020] Figure 3 A schematic diagram of the structure of the airtightness detection device provided in an embodiment of the present application, in which the outer cavity sleeve is pressed down and the detection cavity is evacuated;

[0021] Figure 4 A schematic diagram of the structure of filling a detection gas into a detection cavity of an airtightness detection device provided in an embodiment of the present application;

[0022] Figure 5 A schematic diagram of the structure of the airtightness detection device provided in an embodiment of the present application, in which the inner pressure shaft is pressed down and the detection chamber is evacuated;

[0023] Figure 6 The structure of the schematic diagram of the structure of the inner pressure shaft reset of the airtightness detection device provided in the embodiment of the present application;

[0024] Figure 7 A schematic flow chart of the airtightness detection method provided in an embodiment of the present application.

[0025] Description of reference numerals:

[0026] 100- air tightness detection device;

[0027] 110-external cavity sleeve; 111-movable hole; 112-first sealing end;

[0028] 120-inner pressure shaft; 121-second sealing end; 122-cavity;

[0029] 123-communication hole; 124-sealing groove; 130-detection cavity;

[0030] 140 - venting joint; 150 - first sealing member; 160 - second sealing member;

[0031] 170-seal ring;

[0032] 200 - battery; 210 - cover plate; 220 - annular weld. DETAILED DESCRIPTION

[0033] In the related technology, the helium detection mechanism generally adopts the double-head back pressure method for helium detection (helium pressure head and helium detection head), which has two independent pipeline systems. The specific operation process is: first, the helium pressure head presses helium into the sealing cavity after welding, and then withdraws after maintaining the pressure for a period of time, and then the helium detection head presses down to vacuum and detect helium.

[0034] However, the helium detection mechanism in the related technology, including the helium pressure head and the helium detection head, needs to be equipped with two sets of gas circuit systems, the equipment is relatively complex, and the cost is high; in addition, the detection method of the related technology is to perform vacuum detection after compressing helium, that is, after compressing helium, the helium pressure head is transferred, and the helium detection head is pressed down for vacuum detection. However, during the vacuuming process, the helium in the product cavity is in an uncontrolled state. If the weld leak is large, the helium will be directly extracted during vacuuming, resulting in incorrect judgment and inability to correctly judge whether the product is qualified, and the detection accuracy is poor.

[0035] In response to the above technical problems, the embodiment of the present application provides an airtightness detection device and an airtightness detection method, including an outer cavity sleeve and an inner pressure shaft. On the one hand, a single system can be used to simultaneously realize vacuuming, helium compression and helium detection, which has a simple structure and reduces costs, and helps to avoid sealing problems in the switching process, thereby avoiding the detection gas inside the detection cavity from being drawn away when there is a large leak, realizing the detection of large leaks and avoiding false detections; on the other hand, the design of the inner pressure shaft helps to control the free state of helium during vacuuming, making the detection structure more realistic and effective, and can simplify the entire detection logic and maximize the detection accuracy.

[0036] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below in conjunction with the drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0037] Reference Figure 1 As shown, an embodiment of the present application provides an airtightness detection device 100 for detecting the airtightness of a cavity, wherein a cover plate of the cavity has a sealing opening.

[0038] In this embodiment, there is no limitation on the detection object of the airtightness detection device 100. For example, the airtightness detection device 100 can be used to detect the airtightness of a battery cavity; or, the airtightness detection device 100 can be used to detect the airtightness of other cavities.

[0039] In this embodiment, refer to Figure 1 and Figure 2 As shown, the airtightness detection device 100 is mainly used to detect the airtightness of the cavity of the battery 200 as an example for description. Specifically, after the sealing opening of the battery cover 210 is welded and sealed, an annular weld 220 surrounding the sealing opening is formed. The airtightness detection device 100 mainly detects the airtightness of the cavity of the battery 200 by detecting the airtightness of the annular weld 220.

[0040] Among them, the airtightness detection device 100 of this embodiment can detect empty cavities, and is not limited to cavities after the welding process. As long as it can detect whether the sealing level of the cover area has been reached, it belongs to the protection scope of this application.

[0041] In the present application, refer to Figures 3 to 6 As shown, the air tightness detection device 100 may include an outer cavity sleeve 110 and an inner pressure shaft 120, wherein the outer cavity sleeve 110 has a movable hole 111, and the inner pressure shaft 120 is penetrated through the movable hole 111 and can move along the movable hole 111. It can be understood that the movable hole 111 is a through hole that penetrates the outer cavity sleeve 110 along the length direction of the outer cavity sleeve 110.

[0042] In the embodiment of the present application, the inner pressure shaft 120 moves along the movable hole 111. It should be noted that the moving direction of the inner pressure shaft 120 is not limited. Exemplarily, in the present embodiment, the inner pressure shaft 120 can move up and down along the movable hole 111. In this way, the outer cavity sleeve 110 and the inner pressure shaft 120 form a single system, which can simultaneously realize vacuuming, helium compression and helium detection, with a simple structure and reduced costs; at the same time, the present application only needs to be equipped with a set of gas circuit system, which has higher grafting and helps to improve user experience.

[0043] In the present application, refer to Figures 3 to 6 As shown, the outer cavity sleeve 110 has a first sealing end 112 , which is configured to abut against the cover plate 210 , so that a detection cavity 130 is formed between the inner wall of the movable hole 111 and the cover plate 210 , and the sealing port is located in the detection cavity 130 .

[0044] In this way, when performing air tightness testing, the testing chamber 130 can be evacuated and testing gas can be pressed in; the inner pressure shaft 120 has a second sealing end 121, and when the testing gas in the testing chamber 130 is extracted, the second sealing end 121 abuts against the sealing port.

[0045] In actual operation, when air is extracted from the detection chamber 130 and detection gas is pressed into the detection chamber 130 , the second sealing end 121 is separated from the annular weld 220 ; when detection gas is extracted from the detection chamber 130 , the second sealing end 121 is in contact with the annular weld 220 .

[0046] It should be noted that the step of evacuating the air is performed before the detection gas is pressed in, because the evacuation is to remove the air in the detection chamber 130 and ensure that there is no interference from other gases in the detection environment, thereby reducing the background signal and improving the sensitivity of the detection. In specific operations, evacuating the air first can ensure that there is no interference from other gases in the detection chamber 130, and then by injecting helium and performing detection, it can be more accurately determined whether there is a leak in the detection chamber 130.

[0047] In this embodiment, the outer cavity sleeve 110 has a first sealing end 112, which helps to ensure the sealing of the detection cavity 130 during the detection process, thereby ensuring the detection accuracy; the inner pressure shaft 120 has a second sealing end 121, so that after the helium is injected, the second sealing end 121 is used to seal and press the weld, which helps to prevent helium from overflowing, so that when the helium in the detection cavity 130 is vacuumed to remove, the helium inside the weld will not be extracted.

[0048] In the embodiments of the present application, there is no limitation on the detection gas. For example, the detection gas may be, but is not limited to, helium, nitrogen, hydrogen, etc. In the present embodiment, the detection gas is mainly described as helium. In this way, helium has a small molecular mass and can easily pass through tiny leak holes. Compared with other gases, helium has a higher leakage rate; in addition, helium, as an inert gas, will not chemically react with the surface of the detection object, ensuring the safety of the detection process.

[0049] Therefore, the airtightness detection device 100 provided in this embodiment can simultaneously realize vacuum extraction, helium compression and helium detection using a single system. It has a simple structure and low cost, which helps to avoid sealing problems in the switching process, thereby preventing the detection gas inside the detection chamber 130 from being drawn away when a large leak occurs, thereby realizing the detection of large leaks, avoiding false detections, and improving detection accuracy.

[0050] In a feasible implementation, the first sealing end 112 is disposed around the axial end of the movable hole 111 , and the area enclosed by the axial projection of the first sealing end 112 in the movable hole 111 covers the sealing opening.

[0051] In the embodiment of the present application, the shapes of the first sealing end 112 and the sealing opening are not limited. Exemplarily, the sealing opening can be an annular opening such as a circle or a square, etc., which is not limited in the present embodiment. The shape of the first sealing end 112 can be adapted to the shape of the sealing opening. In this way, it helps to ensure the sealing of the detection cavity 130 during the detection process to the greatest extent, thereby ensuring the detection accuracy.

[0052] In one possible implementation, referring to Figures 3 to 6 As shown, a cavity 122 is provided at one end of the inner pressure shaft 120 facing the cover plate 210, and a second sealing end 121 is arranged around the circumferential edge of the cavity 122. The function of defining the cavity 122 is to allow a space to be provided between the end of the inner pressure shaft 120 and the end of the outer cavity sleeve 110, so as to facilitate the movement of the inner pressure shaft 120 inside the outer cavity sleeve 110. It should be noted that the size of the cavity 122 is not limited and can be set according to actual needs.

[0053] In order to improve the sealing performance and prevent helium from leaking out, in the embodiment of the present application, the contour shape of the second sealing end 121 can match the contour shape of the sealing port. In this way, it helps to ensure the sealing performance of the detection cavity 130 during the detection process to the greatest extent, thereby helping to prevent helium from leaking out during the vacuuming process.

[0054] In one possible implementation, referring to Figures 3 to 6As shown, the side wall of the inner pressure shaft 120 may be provided with a connecting hole 123, and the connecting hole 123 connects the cavity 122 with the outside of the inner pressure shaft 120. In this way, when the detection gas is extracted, it is possible to avoid the detection gas remaining in the cavity 122 at the end of the inner pressure shaft 120. Among them, the shape, size, and opening position of the connecting hole 123 are not limited, and can be specifically set according to actual needs.

[0055] In one possible implementation, referring to Figure 1 , Figures 3 to 6 As shown, the side wall of the outer cavity sleeve 110 may be connected to a ventilation connector 140 , and the ventilation connector 140 is in communication with the detection cavity 130 .

[0056] In the embodiment of the present application, the connecting hole 123 and the vent connector 140 can be arranged relative to each other, so that the vent connector 140 is opposite to the connecting hole 123, which can conveniently realize the circulation and regulation of the detection gas, thereby ensuring the smooth flow of gas during vacuum or pressurization.

[0057] Among them, the main function of the ventilation connector 140 is connection and sealing. It is suitable for various application scenarios that require ventilation and sealing. The ventilation connector 140 is generally composed of components such as a connector, a protective tube, a rubber sealing plug and a waterproof breathable valve. These components together ensure the reliability and sealing of the connection, and have a simple structure and are easy to use.

[0058] In the embodiment of the present application, the vent connector 140 is configured to be connected to any one of a vacuum pump, an air filling tank, and a leak detector. In this way, when vacuuming is required, the vent connector 140 can be connected to the vacuum pump; when nitrogen pressure is required, the vent connector 140 can be connected to the air filling tank; when leak detection is required, the vent connector 140 can be connected to the leak detector. Therefore, the device of this embodiment does not need to switch equipment when vacuuming, nitrogen pressure or leak detection, which helps to avoid sealing problems in the switching process.

[0059] In one possible implementation, referring to Figure 3 , Figure 5 as well as Figure 6 As shown, the first sealing end 112 is provided with a first sealing member 150 , and the first sealing member 150 abuts between the outer cavity sleeve 110 and the cover plate 210 .

[0060] In the embodiment of the present application, there is no limitation on the structure of the first sealing member 150. For example, the first sealing member 150 may be a sealing ring, a sealing tape, a gasket, etc., which is not limited in the present embodiment. In addition, there is no limitation on the material of the first sealing member 150. For example, the material of the first sealing member 150 may include but is not limited to rubber material, silicone material, etc.

[0061] In this way, the first seal 150 abuts between the outer cavity sleeve 110 and the cover plate 210, providing an effective and reliable seal between the two mating surfaces of the outer cavity sleeve 110 and the cover plate 210, preventing gas from escaping under pressure, and helping to prevent contaminants from entering between the outer cavity sleeve 110 and the cover plate 210.

[0062] In a feasible implementation, the second sealing end 121 may be provided with a second sealing member 160 , and the second sealing member 160 abuts against the circumferential edge of the sealing port.

[0063] In the embodiment of the present application, the structure of the second sealing member 160 is not limited. For example, the second sealing member 160 can be a sealing ring, a sealing tape, a gasket, etc., which is not limited in the present embodiment. In addition, the material of the second sealing member 160 is not limited either. For example, the material of the second sealing member 160 can be a rubber material, a silicone material, etc.

[0064] In this way, after the inner pressure shaft 120 is pressed down, the second sealing member 160 abuts against the circumferential edge of the sealing port, which helps to maximize the sealing of the detection chamber 130 during the detection process, thereby helping to prevent helium from leaking out during the vacuuming process.

[0065] In one possible implementation, referring to Figures 3 to 6 As shown, the outer wall of the inner pressure shaft 120 may be provided with a sealing groove 124 surrounding the circumference thereof, and a sealing ring 170 is provided in the sealing groove 124 . The sealing ring 170 at least partially protrudes out of the sealing groove 124 and abuts against the inner wall of the movable hole 111 .

[0066] In the embodiment of the present application, there is no limitation on the number, shape and position of the sealing grooves 124, which can be set according to actual needs. Correspondingly, the number and shape of the sealing rings 170 can be matched with the sealing grooves 124, which helps to improve the sealing performance.

[0067] In the embodiment of the present application, the sealing ring 170 abuts against the inner wall of the movable hole 111, so that the inner wall of the movable hole 111 is in a sealed state, thereby helping to prevent the detection gas from overflowing from the movable hole 111 and further ensuring the sealing performance during the detection process.

[0068] Reference Figure 7 As shown, an embodiment of the present application provides an airtightness detection method, which is used in an airtightness detection device. The method may include:

[0069] S100: driving the outer cavity sleeve to press down and abut against the surface of the cover plate, so that the circumferential outer side of the sealing opening of the cover plate is sealed, and the outer cavity sleeve and the cover plate are surrounded to form a detection cavity.

[0070] In this embodiment, the structure for driving the outer cavity sleeve 110 to be pressed down is not further limited. For example, the outer cavity sleeve 110 can be driven to be pressed down by the first cylinder. In this way, the first cylinder can convert the pressure energy of the compressed air into mechanical energy to drive the outer cavity sleeve 110 to perform linear reciprocating motion, which helps to ensure that the pressing position of the outer cavity sleeve 110 is accurate.

[0071] in, Figure 3 A schematic diagram of the structure for driving the outer cavity sleeve to press downward.

[0072] S200: Connect the vacuum pump to the detection chamber, and evacuate the detection chamber to a first preset pressure value.

[0073] Exemplarily, the vacuum pump and the detection chamber 130 may be connected via a vent connector 140 .

[0074] It should be noted that the first preset pressure value is not limited and can be set according to actual conditions. For example, the first preset pressure value in this embodiment can be pumped to 20 Pa.

[0075] in, Figure 3 FIG. 1 is a schematic diagram of a structure for evacuating a detection chamber. Figure 3 Evacuate in the direction of the arrow.

[0076] S300: connecting the gas filling tank to the detection chamber, and filling the detection chamber with detection gas to a second preset pressure value.

[0077] Exemplarily, the gas filling tank and the detection chamber 130 may be connected via a venting joint 140. Exemplarily, the detection gas may be helium.

[0078] It should be noted that the second preset pressure value is not limited and can be set according to actual conditions. For example, the second preset pressure value in this embodiment can be charged to 0.2 Pa.

[0079] in, Figure 4 Schematic diagram of the structure of filling the detection chamber with detection gas. Figure 4 Fill the test gas in the direction of the arrow.

[0080] S400: After driving the inner pressure shaft downward to seal the sealing port, the vacuum pump is connected to the detection chamber, and the detection chamber is evacuated to a third preset pressure value.

[0081] In this embodiment, the structure for driving the inner pressure shaft 120 to press down is not further limited. For example, the inner pressure shaft 120 can be driven downward by a second cylinder. For example, the third preset pressure value can be pumped to 20 Pa.

[0082] It can be understood that the inner pressure shaft 120 is pressed down to the annular weld 220, and the second seal 160 at the end of the inner pressure shaft 120 presses and seals the annular weld 220. At the same time, the vacuum pump evacuates and draws away the helium in the detection chamber 130 until the vacuum value of the detection chamber 130 reaches 20 Pa.

[0083] in, Figure 5 FIG. 1 is a schematic diagram of a structure in which the inner pressure shaft presses down and evacuates the detection cavity. Specifically, Figure 5 Evacuate in the direction of the arrow.

[0084] S500: driving the inner pressure shaft to reset, and connecting the leak detector with the detection chamber to detect the air tightness of the sealing port.

[0085] Exemplarily, the inner pressure shaft 120 can be driven to reset by the second cylinder, and the leak detector and the detection chamber 130 can be communicated through the vent joint 140. It can be understood that driving the inner pressure shaft 120 to reset means: driving the inner pressure shaft 120 to rise to the initial position.

[0086] in, Figure 6 Schematic diagram of the structure of the internal pressure shaft reset. Specifically, the detection direction of the leak detector can be along Figure 6 Carry out helium inspection in the direction of the middle arrow.

[0087] The embodiment of the present application provides an airtightness detection device and an airtightness detection method, including an outer cavity sleeve and an inner pressure shaft. On the one hand, a single system can be used to simultaneously realize vacuuming, helium compression and helium detection, which has a simple structure and reduces costs, and helps to avoid sealing problems in the switching process, thereby avoiding the detection gas inside the detection cavity from being drawn away when there is a large leak, realizing the detection of large leaks and avoiding false detections; on the other hand, the design of the inner pressure shaft helps to control the free state of helium during vacuuming, and the detection structure is more real and effective, and can simplify the entire detection logic and maximize the detection accuracy.

[0088] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0089] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the 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.

[0090] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein.

[0091] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An airtightness detection device, characterized in that: Used to detect the air tightness of a cavity, the cover plate (210) of the cavity having a sealing opening; the air tightness detection device comprises an outer cavity sleeve (110) and an inner pressure shaft (120), the outer cavity sleeve (110) having a movable hole (111), and the inner pressure shaft (120) is inserted through the movable hole (111) and can move along the movable hole (111); The outer cavity sleeve (110) has a first sealing end (112), and the first sealing end (112) is configured to abut against the cover plate (210), so that a detection cavity (130) is formed between the inner wall of the movable hole (111) and the cover plate (210), and the sealing port is located in the detection cavity (130); when performing airtightness testing, the detection cavity (130) can be evacuated and a detection gas can be pressed into it; The inner pressure shaft (120) has a second sealing end (121), and when the detection gas in the detection chamber (130) is drawn away, the second sealing end (121) abuts against the sealing port.

2. The airtightness detection device according to claim 1, characterized in that: The first sealing end (112) is arranged around the axial end of the movable hole (111), and the first sealing end (112) covers the sealing port in an area surrounded by an axial projection of the movable hole (111).

3. The airtightness detection device according to claim 1, characterized in that: A cavity (122) is provided at one end of the inner pressure shaft (120) facing the cover plate (210), and the second sealing end (121) is arranged around the circumferential edge of the cavity (122); the contour shape of the second sealing end (121) matches the contour shape of the sealing port.

4. The airtightness detection device according to claim 3, characterized in that: A communicating hole (123) is provided on the side wall of the inner pressure shaft (120), and the communicating hole (123) connects the cavity (122) with the outside of the inner pressure shaft (120).

5. The airtightness detection device according to claim 4, characterized in that: The side wall of the outer cavity sleeve (110) is connected to a ventilation joint (140), and the ventilation joint (140) is connected to the detection cavity (130); the ventilation joint (140) is configured to be connected to any one of a vacuum pump, an air filling tank, and a leak detector; the connecting hole (123) is arranged opposite to the ventilation joint (140).

6. The airtightness detection device according to any one of claims 1 to 5, characterized in that: The first sealing end (112) is provided with a first sealing member (150), and the first sealing member (150) is abutted between the outer cavity sleeve (110) and the cover plate (210).

7. The airtightness detection device according to any one of claims 1 to 5, characterized in that: The second sealing end (121) is provided with a second sealing member (160), and the second sealing member (160) abuts against the circumferential edge of the sealing port.

8. The airtightness detection device according to any one of claims 1 to 5, characterized in that: The outer wall of the inner pressure shaft (120) is provided with a sealing groove (124) surrounding the circumference thereof, and a sealing ring (170) is provided in the sealing groove (124). The sealing ring (170) at least partially protrudes out of the sealing groove (124) and abuts against the inner wall of the movable hole (111).

9. The airtightness detection device according to any one of claims 1 to 5, characterized in that: The airtightness detection device is configured to detect the airtightness of the cavity of the battery (200), and the sealing opening of the cover plate (210) is welded and sealed to form an annular weld surrounding the sealing opening; When the detection chamber (130) extracts air and presses detection gas, the second sealing end (121) is separated from the annular weld; when the detection chamber (130) extracts detection gas, the second sealing end (121) abuts against the annular weld.

10. A method for detecting air tightness, characterized in that: Used in the airtightness detection device according to any one of claims 1 to 9; the method comprises: The outer cavity sleeve is driven to be pressed downward to abut against the surface of the cover plate, so that the circumferential outer side of the sealing opening of the cover plate is sealed, and the outer cavity sleeve and the cover plate are surrounded to form a detection cavity; Connecting a vacuum pump to the detection chamber and evacuating the detection chamber to a first preset pressure value; Connecting the gas filling tank to the detection chamber, and filling the detection chamber with detection gas to a second preset pressure value; After driving the inner pressure shaft downward to seal the sealing port, connecting the vacuum pump with the detection chamber, and evacuating the detection chamber to a third preset pressure value; The inner pressure shaft is driven to reset, and a leak detector is connected to the detection chamber to detect the air tightness of the sealing port.

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