Air tightness detection method, air tightness detection device, and battery cell manufacturing system

Abstract

The invention relates to an air tightness detection method, an air tightness detection device and a manufacturing system of a battery monomer. The air tightness detection method comprises the following steps: providing an initial battery; performing vacuum treatment on the initial battery, and filling inert gas into the initial battery to obtain a pre-detected battery; the pre-detected battery is placed in the sealing cavity, and the air pressure in the pre-detected battery is larger than that in the sealing cavity; collecting inert gas parameters in the sealed cavity; determining that the pre-detected battery is a qualified battery under the condition that the inert gas parameter meets the preset parameter; and moving the to-be-detected battery out of the sealed cavity, and extracting inert gas in the to-be-detected battery. According to the air tightness detection method, the air tightness detection precision can be remarkably improved.

Description

Technical Field

[0001] This application relates to the technical field of battery manufacturing, and particularly to a method for detecting airtightness, an airtightness detection device, and a manufacturing system for battery cells. Background Art

[0002] Batteries have the advantages of reliable working performance, no pollution, no memory effect, etc., and are thus widely used. For example, with the increasing attention to environmental protection issues and the growing popularity of new energy vehicles, the demand for batteries will show an explosive growth.

[0003] The airtightness of a battery has an important impact on the performance of the battery. Therefore, how to improve the accuracy of battery airtightness detection is an urgent problem in this field. Summary of the Invention

[0004] Embodiments of this application provide a method for detecting airtightness, an airtightness detection device, and a manufacturing system for battery cells. The method for detecting airtightness can significantly improve the accuracy of airtightness detection.

[0005] In a first aspect, embodiments of this application propose a method for detecting airtightness, which includes: providing an initial battery; subjecting the initial battery to vacuum treatment, filling the initial battery with an inert gas to obtain a pre-inspection battery; placing the pre-inspection battery in a sealed cavity, where the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity; collecting parameters of the inert gas in the sealed cavity; confirming the pre-inspection battery as a qualified battery when the parameters of the inert gas meet preset parameters; removing the pre-inspection battery out of the sealed cavity, and extracting the inert gas in the pre-inspection battery.

[0006] According to the method for detecting airtightness of the embodiments of this application, an inert gas is pre-filled into the initial battery to obtain a pre-inspection battery, and then the pre-inspection battery is placed in a sealed cavity, and a pressure difference is set between the inside of the pre-inspection battery and the sealed cavity. When the pre-inspection battery has a defect, the inert gas in the pre-inspection battery has a tendency to diffuse into the sealed cavity, so that there is a certain concentration of inert gas in the sealed cavity; then, by detecting the parameters of the inert gas in the sealed cavity, it is determined whether there is inert gas leakage, so as to determine whether the pre-inspection battery meets the production requirements; the interference of the process of filling the inert gas on the airtightness detection is reduced, and the accuracy of the airtightness detection is improved; after collecting the parameters of the inert gas, the pre-inspection battery is removed from the sealed cavity and the inert gas in the pre-inspection battery is extracted, further reducing the interference of the process of extracting the inert gas on the airtightness detection, and further improving the accuracy of the airtightness detection.

[0007] In some embodiments, the step of placing the pre-inspection battery in a sealed cavity and having the air pressure in the pre-inspection battery greater than the air pressure in the sealed cavity includes: placing the pre-inspection battery in the sealed cavity, wherein the air pressure in the pre-inspection battery meets a first battery air pressure value; subjecting the sealed cavity to vacuum treatment so that the air pressure in the sealed cavity meets a first cavity air pressure value, and the first cavity air pressure value is less than the first battery air pressure value. By subjecting the sealed cavity to vacuum treatment, a pressure difference is created between the sealed cavity and the pre-inspection battery, which is beneficial for detecting the parameters of the inert gas in the sealed cavity.

[0008] In some embodiments, the first battery air pressure value is from 100 Kpa to 140 Kpa.

[0009] In some embodiments, the first cavity air pressure value is from 10 Pa to 100 Pa.

[0010] In some embodiments, after the step of collecting the parameters of the inert gas in the sealed cavity, the method further includes: confirming that the pre-inspection battery is an abnormal battery when the parameters of the inert gas do not meet the preset parameters.

[0011] In some embodiments, the step of placing the pre-inspection battery in a sealed cavity and having the air pressure in the pre-inspection battery greater than the air pressure in the sealed cavity includes: placing the pre-inspection battery in the sealed cavity, wherein the number of pre-inspection batteries is at least two, and the air pressure of each pre-inspection battery is greater than the air pressure in the sealed cavity. The embodiments of the present application can further improve the efficiency of airtightness detection.

[0012] In some embodiments, after the step of collecting the parameters of the inert gas in the sealed cavity, the method includes: confirming that at least two pre-inspection batteries are abnormal batteries when the parameters of the inert gas do not meet the preset parameters; removing at least two pre-inspection batteries out of the sealed cavity respectively, and filling inert gas into each pre-inspection battery respectively; placing each pre-inspection battery in the corresponding sealed cavity of each pre-inspection battery respectively, wherein the air pressure in each pre-inspection battery is greater than the air pressure in the corresponding sealed cavity of each pre-inspection battery respectively; and collecting the parameters of the inert gas in each sealed cavity respectively.

[0013] Thus, when the embodiments of the present application detect that the parameters of the inert gas do not meet the preset parameters, it is determined that there is at least one abnormal battery in the sealed cavity, and all the batteries in the sealed cavity are further detected to screen out the abnormal batteries, thereby improving the accuracy of airtightness detection.

[0014] In some embodiments, before the step of removing the pre-inspection battery out of the sealed cavity and extracting the inert gas in the pre-inspection battery, the method further includes: injecting a first gas into the sealed cavity so that the air pressure in the sealed cavity meets a second cavity air pressure value. Optionally, the second cavity air pressure value is from 90 KPa to 110 KPa.

[0015] Therefore, in the embodiments of the present application, the steps of filling or extracting inert gas into / from the battery are all performed outside the sealed cavity, which can achieve single-station load reduction, shorten the time required for a single station, improve the overall equipment utilization rate, improve production efficiency, and reduce the manufacturing cost of the battery body.

[0016] In some embodiments, the step of removing the pre-inspected battery outside the sealed cavity and extracting the inert gas in the pre-inspected battery includes: removing the pre-inspected battery outside the sealed cavity and extracting the inert gas in the pre-inspected battery until the air pressure in the pre-inspected battery meets the second battery air pressure value; filling the second gas into the pre-inspected battery so that the air pressure in the pre-inspected battery meets the third battery air pressure value, where the materials of the second gas and the inert gas are different; wherein, the second battery air pressure value is 2 KPa to 10 KPa; and / or the third battery air pressure value is 90 KPa to 101 KPa.

[0017] In some embodiments, the steps of vacuum-treating the initial battery and filling the initial battery with inert gas to obtain a pre-inspected battery include: vacuum-treating the initial battery until the air pressure in the initial battery meets the fourth battery air pressure value, where the fourth battery air pressure value is 30 KPa to 80 KPa; filling the initial battery with inert gas to obtain a pre-inspected battery.

[0018] Therefore, in the embodiments of the present application, vacuum-treating the initial battery makes the inside of the initial battery have a certain degree of vacuum, which is beneficial to filling the initial battery with inert gas.

[0019] In some embodiments, after the step of providing the initial battery, it further includes: providing a seal to the initial battery, where in the first state, the seal seals the initial battery; in the second state, the inside of the initial battery is connected to the external equipment. By providing the seal, it is beneficial to connect or disconnect the inside of the initial battery from the external equipment, facilitating vacuumizing or injecting gas into the initial battery.

[0020] In a second aspect, the embodiments of the present application propose an airtightness detection device, which includes a battery providing module, a first gas filling module, a first moving module, a collection module, a confirmation module, and a second moving module. The battery providing module is used to provide an initial battery; the first gas filling module is used to vacuum-treat the initial battery and fill the initial battery with inert gas to obtain a pre-inspected battery; the first moving module is used to place the pre-inspected battery in a sealed cavity, where the air pressure in the pre-inspected battery is greater than the air pressure in the sealed cavity; the collection module is used to collect the inert gas parameters in the sealed cavity; the confirmation module is used to confirm that the pre-inspected battery is a qualified battery when the inert gas parameters meet the preset parameters; the second moving module is used to remove the pre-inspected battery outside the sealed cavity and extract the inert gas in the pre-inspected battery.

[0021] In some embodiments, the airtightness detection device further includes a second inflation module configured to inject a first gas into the sealed cavity to make the air pressure inside the sealed cavity the same as the external air pressure.

[0022] In some embodiments, the airtightness detection device further includes a sealing provision module configured to provide a seal to the initial battery, wherein in a first state, the seal seals the initial battery; and in a second state, the interior of the initial battery communicates with an external device.

[0023] In a third aspect, the present application provides a manufacturing system for a battery cell, the manufacturing system including the airtightness detection device according to any one of the embodiments of the second aspect of the present application. Description of the Drawings

[0024] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the drawings.

[0025] Figure 1 is a schematic flowchart of an airtightness detection method provided by an embodiment of the present application;

[0026] Figure 2 is a schematic structural diagram of an initial battery provided by an embodiment of the present application;

[0027] Figure 3 is Figure 2 a disassembled schematic diagram of the initial battery shown;

[0028] Figure 4 is a schematic flowchart of step S300 in the airtightness detection method provided by an embodiment of the present application;

[0029] Figure 5 is a schematic flowchart of an airtightness detection method provided by another embodiment of the present application;

[0030] Figure 6 is a schematic flowchart of an airtightness detection method provided by still another embodiment of the present application;

[0031] Figure 7 is a schematic flowchart of an airtightness detection method provided by yet another embodiment of the present application;

[0032] Figure 8 is a schematic structural diagram of a state of a first seal and an initial battery in an embodiment of the present application;

[0033] Figure 9 is a schematic structural diagram of another state of a first seal and an initial battery in an embodiment of the present application;

[0034] Figure 10 is Figure 9 A partially enlarged schematic view of the first seal and the initial battery shown at I;

[0035] Figure 11 A schematic view of the state structure of the third seal and the initial battery in an embodiment of the present application;

[0036] Figure 12 Another schematic view of the state structure of the third seal and the initial battery in an embodiment of the present application;

[0037] Figure 13 is Figure 12 A partially enlarged schematic view of the third seal and the initial battery shown at II;

[0038] Figure 14 A schematic view of the structure of the airtightness detection device in an embodiment of the present application;

[0039] Figure 15 A schematic view of the structure of the airtightness detection device in another embodiment of the present application;

[0040] Figure 16 A schematic view of the structure of the airtightness detection device in still another embodiment of the present application;

[0041] Figure 17 A schematic view of the structure of the manufacturing system of the battery cell in an embodiment of the present application.

[0042] Explanation of the reference numerals is as follows:

[0043] 1, manufacturing system;

[0044] 10, airtightness detection device;

[0045] 11, battery supply module;

[0046] 12, first inflation module;

[0047] 13, first moving module;

[0048] 14, acquisition module;

[0049] 15, confirmation module;

[0050] 16, second moving module;

[0051] 17, second inflation module;

[0052] 18, seal supply module;

[0053] 2. Initial battery; 21. Electrode assembly; 22. Housing assembly; 221. End cap assembly; 2211. Electrode terminal; 222. Housing; 220. Liquid injection port;

[0054] 3. First seal; 31. First sealing portion; 32. First connecting portion;

[0055] 4. Third seal;

[0056] 5. Connecting member. Detailed implementation manners

[0057] Hereinafter, embodiments of the airtightness detection method, the airtightness detection device, and the manufacturing system of battery cells of the present application are specifically disclosed with appropriate reference to the drawings. However, there may be cases where unnecessary details are omitted. For example, there are cases where details of well-known matters are omitted and repeated descriptions of actually identical structures are omitted. This is to prevent the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter recited in the claims.

[0058] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a specific range. The range defined in this way can include the end values or not include the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, ranges of 60 to 110 and 80 to 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 to 5" have been fully listed herein, and "0 to 5" is only an abbreviated representation of these numerical combinations. In addition, when it is stated that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0059] If there is no special instruction, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0060] If there is no special instruction, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0061] Unless otherwise specified, all steps S of this application can be carried out sequentially or randomly, and preferably sequentially. For example, if the method includes steps S(a) and (b), it means that the method may include steps S(a) and (b) carried out sequentially, or may also include steps S(b) and (a) carried out sequentially. For example, if it is mentioned that the method may further include step S(c), it means that step S(c) can be added to the method in any order. For example, the method may include steps S(a), (b) and (c), or may also include steps S(a), (c) and (b), or may include steps S(c), (a) and (b), etc.

[0062] In the description of the embodiments of this application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of this application and simplifying the description, rather than indicating or implying 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 construed as a limitation on the embodiments of this application.

[0063] In addition, technical terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0064] In the description of the embodiments of this application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific situations.

[0065] In the embodiments of this application, the terms "a plurality" and "a variety" refer to two or more than two.

[0066] In the embodiments of the present application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, etc., and the embodiments of the present application are not limited thereto. The battery cell may be in a cylindrical shape, a flat shape, a cuboid shape or other shapes, and the embodiments of the present application are not limited thereto either. Generally, the battery cells are divided into three types according to the encapsulation method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application are not limited thereto.

[0067] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack, etc. Generally, the battery includes a box body for encapsulating one or more battery cells. The box body can prevent liquids or other foreign matters from affecting the charging or discharging of the battery cells.

[0068] The battery cell includes a housing assembly, an electrode assembly and an electrolyte, and the electrode assembly includes a positive electrode plate, a negative electrode plate and a separator. The battery cell mainly works by the movement of metal ions through the electrolyte between the positive electrode plate and the negative electrode plate.

[0069] The manufacturing process of the battery cell includes an electrode manufacturing process, an assembly process and a post-injection process. Since the battery cell has high requirements for the strength, waterproofness and insulation of the housing assembly, during the manufacturing process of the battery cell, it is necessary to perform a sealing test (i.e., airtightness test) on the battery cell.

[0070] In the related art, usually the battery cell to be tested is placed in a sealed cavity, the battery cell and the sealed cavity are evacuated synchronously, and after evacuation, helium is injected into the battery cell. The helium detector is connected to the sealed cavity. If there are packaging defects in the battery cell, there is a certain concentration of helium in the sealed cavity, and the helium detector can detect the helium concentration value in the sealed cavity; after the detection is completed, the helium in the battery cell is pumped out, and then the vacuum in the battery cell and the sealed cavity is released to restore to the atmospheric pressure state; then the battery cell is removed from the sealed cavity and enters the next process.

[0071] The above detection method has a risk of overkill. Overkill means misdetecting a battery cell that meets the requirements as a battery cell that does not meet the requirements; the reason for overkill is that if there is helium leakage during the helium filling process of the battery cell, the helium detector cannot distinguish, so that this part of the battery cells is regarded as battery cells that do not meet the requirements, resulting in poor accuracy of the airtightness detection.

[0072] In view of the above problems, in the embodiments of the present application, the helium filling and helium pumping processes are carried out outside the sealed cavity to reduce the interference risk caused by helium leakage to the airtightness detection and improve the accuracy of the airtightness detection.

[0073] An embodiment of the present application provides a method for airtightness detection.

[0074] As Figure 1 shown, the airtightness detection method includes:

[0075] Step S100: Provide an initial battery.

[0076] Step S200: Vacuum-treat the initial battery and fill the initial battery with an inert gas to obtain a pre-inspection battery.

[0077] Step S300: Place the pre-inspection battery in a sealed cavity, where the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity.

[0078] Step S400: Collect the parameters of the inert gas in the sealed cavity.

[0079] Step S500: Confirm that the pre-inspection battery is a qualified battery when the parameters of the inert gas meet the preset parameters.

[0080] Step S600: Remove the pre-inspection battery from the sealed cavity and extract the inert gas in the pre-inspection battery.

[0081] According to the airtightness detection method of the embodiment of the present application, an inert gas is pre-filled into the initial battery as a pre-inspection battery, and then the pre-inspection battery is placed in a sealed cavity, and a pressure difference is set between the inside of the pre-inspection battery and the sealed cavity, so that when the pre-inspection battery has a defect, the inert gas in the pre-inspection battery has a tendency to diffuse into the sealed cavity, so that there is a certain concentration of inert gas in the sealed cavity; furthermore, by detecting the parameters of the inert gas in the sealed cavity, it is judged whether there is inert gas leakage, so as to judge whether the pre-inspection battery meets the production requirements; the interference of the process of filling the inert gas to the airtightness detection is reduced, and the accuracy of the airtightness detection is improved; after collecting the parameters of the inert gas, the pre-inspection battery is removed from the sealed cavity and the inert gas in the pre-inspection battery is extracted, further reducing the interference of the process of extracting the inert gas to the airtightness detection and further improving the accuracy of the airtightness detection.

[0082] [Step S100]

[0083] Provide an initial battery.

[0084] In the embodiment of the present application, the initial battery, the pre-inspection battery, etc. are different states of the battery cell. For example, the initial battery is a battery cell sample to be detected for airtightness, and the pre-inspection battery is a battery cell filled with an inert gas; although the states of the initial battery and the pre-inspection battery are different, the mechanical structures of the initial battery and the pre-inspection battery are the same. Taking the initial battery as an example, its mechanical structure is described.

[0085] As Figure 2 and Figure 3As shown, in some embodiments, the initial battery 2 includes an electrode assembly 21 and a housing assembly 22. The electrode assembly 21 is located within the housing assembly 22. The electrode assembly 21 includes a positive electrode plate, a negative electrode plate, and a separator. The separator is located between the positive electrode plate and the negative electrode plate to isolate them from each other.

[0086] In the initial battery 2, the housing assembly 22 includes an end - cap assembly 221 and a housing 222. The electrode assembly 21 is located inside the housing 222. The end - cap assembly 221 is connected to the housing 222 to enclose the electrode assembly 21. The end - cap assembly 221 includes an end - cap and functional components such as electrode terminals 2211 provided on the end - cap. The electrode terminals 2211 can be used to electrically connect to the electrode assembly 21 for outputting or inputting electrical energy of the battery cell. The material of the end - cap can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The embodiments of the present application do not impose special restrictions on this. A liquid injection port 220 can be provided on the end - cap assembly 221 for communicating the inside of the initial battery 2 with external devices. Optionally, the liquid injection port 220 can cooperate with a seal to seal the liquid injection port 220, so that the inside of the initial battery 2 is isolated from the external environment, reducing the influence of the external environment on the inside of the initial battery 2. For example, in the sealed case, the air pressure inside the initial battery 2 is basically not affected by the external environment.

[0087] [Step S200]

[0088] Vacuum - process the initial battery and fill the initial battery with an inert gas to obtain a pre - inspected battery.

[0089] To detect the airtightness of the initial battery, an inert gas is pre - filled into the initial battery. Before filling the inert gas, first reduce the air pressure inside the initial battery, that is, vacuum - process the initial battery.

[0090] Specifically, in some embodiments, step S200 may include:

[0091] Step S210, vacuum - process the initial battery until the air pressure in the initial battery meets a fourth battery air - pressure value, where the fourth battery air - pressure value is from 30 KPa to 80 KPa.

[0092] Vacuum - processing the initial battery makes the inside of the initial battery have a certain degree of vacuum, which is conducive to filling the initial battery with an inert gas. The air pressure inside the initial battery meets the fourth battery air - pressure value. The fourth battery air - pressure value can be 30 KPa, 40 KPa, 50 KPa, 60 KPa, 70 KPa, 80 KPa or a range composed of any two of the above values.

[0093] Step S220, fill the initial battery with an inert gas to obtain a pre - inspected battery.

[0094] The inert gas may include helium, argon, etc., and helium is optionally selected. The above-mentioned inert gas basically does not undergo side reactions with the components inside the initial battery and is basically not affected by environmental factors such as temperature and humidity, which can reduce the interference of external environmental factors on the airtightness detection. Helium has a relatively small molecular weight and can pass through relatively small pores. When there are small pores in the outer shell assembly of the initial battery, helium molecules can diffuse into the sealed cavity through the small pores, thereby improving the airtightness detection accuracy.

[0095] Optionally, the air pressure value in the pre-inspection battery can meet the first battery air pressure value. The first battery air pressure value is 100 Kpa to 140 Kpa, optionally greater than 101 KPa and less than or equal to 140 KPa, presenting a positive pressure state, which is beneficial to forming a pressure difference with the sealed cavity. For example, the first battery air pressure value is 100 KPa, 110 KPa, 120 KPa, 130 KPa, 140 KPa or the range composed of any two of the above values.

[0096] [Step S300]

[0097] Place the pre-inspection battery in the sealed cavity, where the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity.

[0098] By setting the pressure difference between the pre-inspection battery and the sealed cavity, the inert gas in the pre-inspection battery has the driving force to diffuse into the sealed cavity; when there are packaging defects in the pre-inspection battery, such as pores in the outer shell assembly, the inert gas can diffuse into the sealed cavity through the pores, so as to judge the airtightness of the pre-inspection battery by detecting the parameters of the inert gas in the sealed cavity. Of course, when there are basically no packaging defects in the pre-inspection battery, the inert gas is encapsulated inside the pre-inspection battery and basically does not leak.

[0099] As Figure 4 shown, in some embodiments, step S300 may include:

[0100] Step S310, place the pre-inspection battery in the sealed cavity, where the air pressure in the pre-inspection battery meets the first battery air pressure value.

[0101] Optionally, the first battery air pressure value is 100 Kpa to 140 Kpa, optionally greater than 101 KPa and less than or equal to 140 KPa.

[0102] In the embodiments of the present application, at least one pre-inspection battery can be detected simultaneously, such as one, two, three, five, or ten pre-inspection batteries, etc. Taking the case where there are at least two pre-inspection batteries as an example, after filling at least two pre-inspection batteries with helium, the at least two pre-inspection batteries are placed in the same sealed cavity; and the air pressure of each pre-inspection battery is greater than the air pressure in the sealed cavity, so that there is a pressure difference between the inside of each pre-inspection battery and the sealed cavity. When multiple pre-inspection batteries are placed in the sealed cavity at the same time, the airtightness detection efficiency can be further improved. For example, if it is detected that the parameters of the inert gas in the sealed cavity meet the preset parameters, all the pre-inspection batteries in the sealed cavity are qualified batteries.

[0103] Step S320, vacuum-treat the sealed cavity so that the air pressure in the sealed cavity meets the first cavity air pressure value, and the first cavity air pressure value is less than the first battery air pressure value.

[0104] By extracting the gas in the sealed cavity, a certain degree of vacuum is created in the sealed cavity, thereby forming a pressure difference between the sealed cavity and the pre-inspection battery.

[0105] Optionally, the first cavity air pressure value is 10 Pa to 100 Pa. Exemplarily, the first cavity air pressure value can be 10 Pa, 20 Pa, 30 Pa, 50 Pa, 60 Pa, 70 Pa, 80 Pa, 100 Pa or the range composed of any two of the above values.

[0106] [Step S400]

[0107] Collect the parameters of the inert gas in the sealed cavity. The parameters of the inert gas can be the mass concentration or volume concentration of the inert gas, etc.

[0108] As Figure 5 shown, after collecting the parameters of the inert gas in the sealed cavity, it is necessary to determine whether the parameters of the inert gas meet the preset parameters. There are two judgment results. One is that the preset parameters are met, and the other is that the preset parameters are not met. After collecting the parameters of the inert gas, the pre-inspection battery needs to be removed from the sealed cavity.

[0109] [Step S500]

[0110] Confirm that the pre-inspection battery is a qualified battery when the parameters of the inert gas meet the preset parameters.

[0111] The preset parameters can be the numerical range of the mass concentration of the inert gas or the volume concentration range, etc. For example, the preset parameter is that the volume concentration of the inert gas ≤ 1×10 -5 , of course, the preset parameter can also be other numerical ranges such as the volume concentration ≤ 5×10 -5etc. When the parameters of the inert gas collected meet the above ranges, it indicates that there is basically no leakage of the inert gas in the pre-inspection battery; it can be determined that the airtightness of the pre-inspection battery is excellent, and it is used as a qualified battery.

[0112] [Step S401]

[0113] When the parameters of the inert gas do not meet the preset parameters, confirm that the pre-inspection battery is an abnormal battery.

[0114] When the parameters of the inert gas collected are greater than 1×10 -5 , it indicates that there is a certain concentration of inert gas in the sealed cavity, and there is leakage of the inert gas in the pre-inspection battery. It can be judged that the airtightness of the pre-inspection battery is poor, and it is used as an abnormal battery to distinguish it from the qualified battery.

[0115] In some embodiments, when there are multiple pre-inspection batteries in the sealed cavity, after step S400, it may further include:

[0116] Step S410, when the parameters of the inert gas do not meet the preset parameters, confirm that at least two pre-inspection batteries are abnormal batteries;

[0117] When there are multiple pre-inspection batteries in the sealed cavity and at least one of the multiple pre-inspection batteries has a leakage problem, there will be inert gas in the sealed cavity, resulting in the parameters of the collected inert gas not meeting the preset parameters. In this case, it is impossible to determine which battery in the multiple pre-inspection batteries specifically has an airtightness problem, and it is necessary to re-detect the multiple pre-inspection batteries to exclude the batteries with airtightness problems.

[0118] Step S420, remove at least two pre-inspection batteries out of the sealed cavity respectively, and fill each pre-inspection battery with inert gas;

[0119] After all the pre-inspection batteries in the sealed cavity are removed from the sealed cavity, since at least one of the multiple pre-inspection batteries may have a leakage, inert gas is re-filled into each pre-inspection battery so that the air pressure in each pre-inspection battery meets the first battery air pressure value. Of course, it is also possible to re-vacuum the multiple pre-inspection batteries, and then inject inert gas after the vacuum treatment so that the air pressure in each pre-inspection battery meets the first battery air pressure value.

[0120] Step S430, place each pre-inspection battery in the corresponding sealed cavity of each pre-inspection battery, where the air pressure in each pre-inspection battery is greater than the air pressure in the corresponding sealed cavity of each pre-inspection battery.

[0121] Place the pre-inspection batteries in different sealed cavities respectively, with one pre-inspection battery placed in each sealed cavity, and conduct targeted detection on each pre-inspection battery.

[0122] Step S440: Collect the inert gas parameters in each sealed cavity respectively.

[0123] Collect the inert gas parameters for each sealed cavity respectively, and judge and analyze the collected parameters respectively. If the inert gas parameters meet the preset parameters, confirm that the pre-inspected battery is a qualified battery; if the inert gas parameters do not meet the preset parameters, confirm that the pre-inspected battery is an abnormal battery, so as to identify the abnormal battery.

[0124] Thus, when the implementation mode of the present application detects that the inert gas parameters do not meet the preset parameters, it is determined that there is at least one abnormal battery in the sealed cavity, and all the batteries in the sealed cavity are further detected to screen out the abnormal battery, thereby improving the accuracy of airtightness detection.

[0125] [Step S600]

[0126] Remove the pre-inspected battery out of the sealed cavity and extract the inert gas in the pre-inspected battery.

[0127] The sealed cavity is mainly used for inert gas leakage detection. The steps of filling inert gas into the battery or extracting inert gas are all carried out outside the sealed cavity, which can achieve single-station load reduction, shorten the time required for a single station, improve the overall equipment utilization rate, improve production efficiency, and reduce the manufacturing cost of a single battery.

[0128] Furthermore, after extracting the inert gas, a second gas is filled into the pre-inspected battery, wherein the second gas is different in material from the inert gas. The second gas can be air, argon, etc., and air is optionally selected. By filling the second gas into the pre-inspected battery, the pressure inside the pre-inspected battery is basically balanced with the external pressure, or slightly less than the external pressure, presenting a slightly negative pressure state.

[0129] In some implementation modes, Step S600 may include:

[0130] Step S610: Remove the pre-inspected battery out of the sealed cavity and extract the inert gas in the pre-inspected battery until the air pressure in the pre-inspected battery meets the second battery air pressure value;

[0131] Step S620: Fill the pre-inspected battery with a second gas so that the air pressure in the pre-inspected battery meets the third battery air pressure value.

[0132] After extracting the inert gas in the pre-inspected battery, there is a certain degree of vacuum inside the pre-inspected battery. For example, the air pressure value inside the pre-inspected battery meets the second battery air pressure value, and the second battery air pressure value is 2 KPa to 10 KPa; when the air pressure value inside the pre-inspected battery is the above value, it is beneficial to fill the second gas into the pre-inspected battery. Exemplarily, the second battery air pressure value can be 2 Pa, 3 Pa, 5 Pa, 6 Pa, 7 Pa, 8 Pa, 10 Pa or the range composed of any two of the above values.

[0133] After filling the pre-inspection battery with the second gas, the pressure inside the pre-inspection battery increases. The air pressure inside the pre-inspection battery meets the third battery air pressure value, and the third battery air pressure value is from 90 KPa to 101 KPa, and can be selected from 90 KPa to 100 KPa. For example, the third battery air pressure value can be 90 KPa, 91 KPa, 92 KPa, 93 KPa, 94 KPa, 95 KPa, 96 KPa, 97 KPa, 98 KPa, 99 KPa, 100 KPa, 101 KPa or a range composed of any two of the above values.

[0134] As Figure 6 shown, in some embodiments, before step S600, the airtightness detection method may further include:

[0135] Step S700, injecting the first gas into the sealed cavity so that the air pressure in the sealed cavity meets the second cavity air pressure value. Optionally, the second cavity air pressure value is from 90 KPa to 110 KPa, and can be selected from 102 KPa to 110 KPa. For example, the second cavity air pressure value can be 90 KPa, 91 KPa, 92 KPa, 93 KPa, 94 KPa, 95 KPa, 96 KPa, 97 KPa, 98 KPa, 99 KPa, 100 KPa, 101 KPa, 102 KPa, 103 KPa, 104 KPa, 105 KPa, 106 KPa, 107 KPa, 108 KPa, 109 KPa, 110 KPa or a range composed of any two of the above values.

[0136] Before removing the pre-inspection battery from the airtight cavity, inject the first gas into the sealed cavity so that the air pressure in the sealed cavity is basically balanced with the external air pressure and even presents a slightly positive pressure state. The first gas can be air or the like. In the embodiments of the present application, the external air pressure may refer to the air pressure of the environment where the sealed cavity is located.

[0137] As Figure 7 shown, in some embodiments, after step S100, the airtightness detection method may further include:

[0138] Step S800, providing a seal to the initial battery, wherein in the first state, the seal seals the initial battery; in the second state, the inside of the initial battery is communicated with the external device. By setting the seal, it is beneficial to connect or disconnect the inside of the initial battery from the external device, facilitating evacuation or gas injection of the initial battery.

[0139] Optionally, the initial battery includes a liquid injection port, through which the inside of the initial battery can be communicated with the external environment for extracting the gas inside the initial battery or injecting gas. The initial battery can be sealed with a seal, for example, by sealing the liquid injection port of the initial battery with a seal.

[0140] The structure of the seal has various forms. Through the function of the seal, the initial battery can include a first state and a second state. In the first state, the seal seals the initial battery, disconnecting the interior of the initial battery from the external environment; in the second state, the interior of the initial battery is connected to external devices for extracting or injecting gas.

[0141] The seal can achieve the connection or disconnection between the interior and the external environment of the initial battery with the help of an external force. In the case of connection, operations such as vacuum pumping and gas injection can be achieved. In this case, the seal can be a first seal or a second seal.

[0142] As Figures 8 to 10 shown, for example, when the first seal 3 is subjected to an external force such as lifting, it connects the interior and the external environment of the initial battery 2; when subjected to an external force such as pressing down or without an external force, it disconnects the interior and the external environment of the initial battery 2, isolating the interior of the initial battery 2 from the external environment.

[0143] Exemplarily, the first seal 3 includes a first sealing portion 31 and a first connecting portion 32. The first sealing portion 31 is connected to the first connecting portion 32. The first sealing portion 31 is used to be disposed at the liquid injection port 220 to seal the liquid injection port 220. The first connecting portion 32 is located outside the initial battery 2, and the cross-section of the first connecting portion 32 is larger than the cross-section of the liquid injection port 220. Matching the above structural form of the first seal 3, the structure of the initial battery 2 is designed accordingly. For example, a liquid injection port 220 can be provided on the end cap, and the first sealing portion 31 is provided inside the liquid injection port 220. The liquid injection port 220 can be set in a form with a gradually changing cross-sectional area. For example, in the direction from the end cap to the electrode assembly, the cross-sectional size of the liquid injection port 220 gradually decreases, and the cross-section of the liquid injection port 220 is perpendicular to the direction from the end cap to the electrode assembly. The structural form of the first sealing portion 31 can be adapted to the form of the liquid injection port 220. For example, the first sealing portion 31 can also be set in a form with a gradually changing cross-sectional area.

[0144] In this case, applying a force F to the first seal 3, for example, lifting the first seal 3 upward, the first connecting portion 32 drives the first sealing portion 31 to move in a direction away from the electrode assembly. There is a gap between the first sealing portion 31 and the cavity wall of the liquid injection port 220, enabling the interior of the initial battery 2 to communicate with the external environment, which can be used for gas injection or vacuum extraction and other treatments. When it is necessary to seal the initial battery 2, applying a force to the first seal 3, for example, pressing down the first seal 3, the first sealing portion 31 seals the liquid injection port 220; of course, when it is necessary to seal the initial battery 2, it is also possible not to apply a force to the first seal 3, allowing the first seal 3 to move downward under its own gravity to make the first sealing portion 31 seal the liquid injection port 220.

[0145] For another example, the seal can also be a second seal. When it is necessary to connect the interior and exterior environments of the initial battery, a force can be applied, such as pressing down on the second seal; when it is necessary to seal the initial battery, a force can be applied, such as lifting the second seal, or it can be achieved through the elastic deformation ability of the second seal itself; the second seal can adopt any sealing structure in the art that can achieve this function, and the structure of the second seal is not further limited in this application.

[0146] For yet another example, the seal can utilize an external component to connect or disconnect the interior and exterior environments of the initial battery. In the connected state, operations such as evacuating and injecting gas can be carried out. In this case, the seal can be a third seal or the like.

[0147] As Figures 11 to 12 shown, by way of example, the third seal 4 can be an elastic member such as a rubber sealing nail. The third seal 4 has a through-hole that can connect the interior and exterior environments of the initial battery 2. However, since the third seal 4 is an elastic member, when the third seal 4 is disposed at the liquid injection port 220, the through-hole in the third seal 4 may be blocked by extrusion; when it is necessary to connect the interior and exterior environments of the initial battery 2, the connecting member 5 can be inserted into the through-hole of the third seal 4. The connecting member 5 can be a rigid member, and the interior of the connecting member 5 is a hollow structure. The connecting member 5 can connect the interior and exterior environments of the initial battery 2. When it is necessary to seal the initial battery 2, the connecting member 5 is removed, and the through-hole is blocked by the elastic deformation ability of the third seal 4 itself, so that the interior and exterior environments of the initial battery 2 are isolated.

[0148] When the seal is the first seal or the second seal, the airtightness detection method can include the following steps:

[0149] Step S100, provide an initial battery;

[0150] Step S801, provide a seal to the initial battery;

[0151] Step S201, apply a force to the seal to connect the interior of the initial battery and an external vacuum device, and vacuum-treat the initial battery; after vacuum-treating the initial battery, apply a force to the seal to disconnect the interior and exterior environments of the initial battery;

[0152] Step S202, apply a force to the seal to connect the interior of the initial battery and an external vacuum device, and fill the initial battery with an inert gas; after filling with the inert gas, apply a force to the seal to disconnect the interior and exterior environments of the initial battery to obtain a pre-inspection battery;

[0153] Step S300, place the pre-inspection battery in a sealed cavity, where the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity;

[0154] Step S400, collect the parameters of the inert gas in the sealed cavity;

[0155] Step S500, confirm that the pre-inspected battery is a qualified battery when the inert gas parameters meet the preset parameters;

[0156] Step S601, move the pre-inspected battery out of the sealed cavity, apply a force to the seal to connect the inside and outside of the initial battery to the vacuum device, extract the inert gas in the pre-inspected battery, after the extraction process of the initial battery, apply a force to the seal to disconnect the inside and outside of the initial battery from the environment;

[0157] Step S602, apply a force to the seal to connect the inside and outside of the initial battery to the vacuum device, fill the pre-inspected battery with a second gas, after filling with the second gas, apply a force to the seal to disconnect the inside and outside of the initial battery from the environment.

[0158] In the case where the seal is a third seal, the airtightness detection method may include the following steps:

[0159] Step S100, provide an initial battery;

[0160] Step S802, provide a seal to the initial battery;

[0161] Step S203, provide a connecting member to the seal to connect the inside and outside of the initial battery to the vacuum device, vacuum process the initial battery; after the vacuum process of the initial battery, remove the connecting member to disconnect the inside and outside of the initial battery from the environment;

[0162] Step S204, provide a connecting member to the seal to connect the inside and outside of the initial battery to the vacuum device, fill the initial battery with an inert gas; after filling with the inert gas, remove the connecting member to disconnect the inside and outside of the initial battery from the environment to obtain a pre-inspected battery;

[0163] Step S300, place the pre-inspected battery in the sealed cavity, wherein the air pressure in the pre-inspected battery is greater than the air pressure in the sealed cavity;

[0164] Step S400, collect the parameters of the inert gas in the sealed cavity;

[0165] Step S500, confirm that the pre-inspected battery is a qualified battery when the inert gas parameters meet the preset parameters;

[0166] Step S603, move the pre-inspected battery out of the sealed cavity, provide a connecting member to the seal to connect the inside and outside of the initial battery to the vacuum device, extract the inert gas in the pre-inspected battery, after the extraction process of the initial battery, remove the connecting member to disconnect the inside and outside of the initial battery from the environment;

[0167] Step S604: Provide a connecting component to the sealing component to connect the inside of the initial battery and the external vacuum device, fill the pre-inspection battery with a second gas, and after filling the second gas, remove the connecting component to disconnect the inside of the initial battery from the external environment.

[0168] An embodiment of the present application also provides an airtightness detection device, which can be used to implement the airtightness detection method of any of the above embodiments of the present application.

[0169] As Figure 14 shown, the airtightness detection device 10 includes a battery providing module 11, a first gas filling module 12, a first moving module 13, a collection module 14, a confirmation module 15, and a second moving module 16. The battery providing module 11 is used to provide an initial battery; the first gas filling module 12 is used to vacuum process the initial battery and fill the initial battery with an inert gas to obtain a pre-inspection battery; the first moving module 13 is used to place the pre-inspection battery in a sealed cavity, wherein the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity; the collection module 14 is used to collect the inert gas parameters in the sealed cavity; the confirmation module 15 is used to confirm that the pre-inspection battery is a qualified battery when the inert gas parameters meet the preset parameters; the second moving module 16 is used to move the pre-inspection battery out of the sealed cavity and extract the inert gas in the pre-inspection battery.

[0170] Optionally, the confirmation module 15 is further used to confirm that the pre-inspection battery is an abnormal battery when the inert gas parameters do not meet the preset parameters.

[0171] Optionally, the first moving module 13 is used to place the pre-inspection battery in the sealed cavity, wherein the air pressure in the pre-inspection battery meets a first battery air pressure value; and is used to vacuum process the sealed cavity to make the air pressure in the sealed cavity meet a first cavity air pressure value, and the first cavity air pressure value is less than the first battery air pressure value.

[0172] Optionally, the first gas filling module 12 is used to vacuum process the initial battery until the air pressure in the initial battery meets a fourth battery air pressure value; and is used to fill the initial battery with an inert gas to obtain a pre-inspection battery.

[0173] As Figure 15 shown, in some embodiments, the airtightness detection device 10 further includes a second gas filling module 17, which is used to inject a first gas into the sealed cavity to make the air pressure in the sealed cavity meet a second cavity air pressure value.

[0174] As Figure 16 shown, in some embodiments, the airtightness detection device 10 further includes a sealing providing module 18, which is used to provide a sealing component to the initial battery, wherein in the first state, the sealing component seals the initial battery; in the second state, the inside and outside of the initial battery are connected.

[0175] Each of the above modules can adopt devices well-known in the art, and their specific structural forms will not be elaborated herein.

[0176] The embodiment of the present application also provides a manufacturing system for a battery cell.

[0177] As Figure 17 shown, the manufacturing system 1 of the battery cell includes the airtightness detection device 10 of any one of the above embodiments of the present application, and the airtightness detection device 10 is configured to perform airtightness detection on the battery cell.

[0178] In some embodiments, the manufacturing system 1 may further include a pole piece manufacturing device, and the pole piece manufacturing device is used to manufacture a positive pole piece, a negative pole piece, etc.

[0179] In some embodiments, the manufacturing system 1 may further include an electrode assembly manufacturing device, and the electrode assembly manufacturing device is used to wind or stack the positive pole piece, the separator and the negative pole piece into an electrode assembly.

[0180] In some embodiments, the manufacturing system 1 may further include a casing device, and the casing device is used to assemble the electrode assembly into the casing.

[0181] In some embodiments, the manufacturing system 1 may further include a sealing device, and the sealing device is used to seal the casing.

[0182] In some embodiments, the manufacturing system 1 may further include a liquid injection device, and the liquid injection device is used to inject electrolyte into the battery cell.

[0183] In some embodiments, the manufacturing system 1 may further include a formation device, and the formation device is used to perform formation operation on the battery cell to activate the active substances in the electrode assembly, etc.

[0184] Of course, the manufacturing system 1 may further include devices that are well-known in the art and essential for manufacturing the battery cell in addition to the above-listed devices, which will not be elaborated herein.

[0185] Although the illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments cannot be construed as a limitation of the present application, and the embodiments can be changed, substituted and modified without departing from the spirit, principle and scope of the present application.

Claims

1. An airtightness detection method, characterized in that, Including: Providing an initial battery; Vacuum-treating the initial battery and filling the initial battery with an inert gas to obtain a pre-inspection battery; Placing the pre-inspection battery in a sealed cavity, wherein the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity; Collecting the inert gas parameters in the sealed cavity; Confirming that the pre-inspection battery is a qualified battery when the inert gas parameters meet the preset parameters; Removing the pre-inspection battery out of the sealed cavity and extracting the inert gas in the pre-inspection battery.

2. The airtightness detection method according to claim 1, wherein The step of placing the pre-inspection battery in a sealed cavity, wherein the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity, includes: Placing the pre-inspection battery in a sealed cavity, wherein the air pressure in the pre-inspection battery meets a first battery air pressure value; Vacuum-treating the sealed cavity so that the air pressure in the sealed cavity meets a first cavity air pressure value, and the first cavity air pressure value is less than the first battery air pressure value.

3. The airtightness detection method according to claim 2, wherein The first battery air pressure value is 100 Kpa to 140 Kpa; and / or the first cavity air pressure value is 10 Pa to 100 Pa.

4. The airtightness detection method according to any one of claims 1 to 3, characterized in that, After the step of collecting the inert gas parameters in the sealed cavity, it further includes: Confirming that the pre-inspection battery is an abnormal battery when the inert gas parameters do not meet the preset parameters.

5. The airtightness detection method according to any one of claims 1 to 4, characterized in that, The step of placing the pre-inspection battery in a sealed cavity, wherein the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity, includes: Placing the pre-inspection battery in a sealed cavity, wherein the number of the pre-inspection batteries is at least two, and the air pressure of each pre-inspection battery is greater than the air pressure in the sealed cavity.

6. The airtightness detection method according to claim 5, characterized in that, After the step of collecting the inert gas parameters in the sealed cavity, it further includes: Confirming that the at least two pre-inspection batteries are abnormal batteries when the inert gas parameters do not meet the preset parameters; Removing at least two pre-inspection batteries out of the sealed cavity respectively and filling each pre-inspection battery with an inert gas; Placing each pre-inspection battery in the corresponding sealed cavity of each pre-inspection battery, wherein the air pressure in each pre-inspection battery is greater than the air pressure in the corresponding sealed cavity of each pre-inspection battery; Collecting the inert gas parameters in each sealed cavity respectively.

7. The airtightness detection method according to any one of claims 1 to 6, characterized in that, Before the step of removing the pre-inspection battery out of the sealed cavity and extracting the inert gas in the pre-inspection battery, it further includes: Injecting a first gas into the sealed cavity so that the air pressure in the sealed cavity meets a second cavity air pressure value.

8. The airtightness detection method according to any one of claims 1 to 7, characterized in that, The step of removing the pre-inspection battery out of the sealed cavity and extracting the inert gas in the pre-inspection battery includes: Removing the pre-inspection battery out of the sealed cavity and extracting the inert gas in the pre-inspection battery until the air pressure in the pre-inspection battery meets a second battery air pressure value; Filling the pre-inspection battery with a second gas so that the air pressure in the pre-inspection battery meets a third battery air pressure value, wherein the second gas and the inert gas are different in material; Wherein, The second battery air pressure value is 2 KPa to 10 KPa; and / or the third battery air pressure value is 90 KPa to 101 KPa.

9. The airtightness detection method according to any one of claims 1 to 8, characterized in that The step of subjecting the initial battery to vacuum treatment and filling the initial battery with an inert gas to obtain a pre-inspection battery includes: Subjecting the initial battery to vacuum treatment until the air pressure in the initial battery meets a fourth battery air pressure value, where the fourth battery air pressure value is 30 KPa to 80 KPa; Filling the initial battery with an inert gas to obtain a pre-inspection battery.

10. The airtightness detection method according to any one of claims 1 to 9, characterized in that, After the step of providing the initial battery, it further includes: Providing a seal to the initial battery, where in the first state, the seal seals the initial battery; in the second state, the inside of the initial battery is in communication with external equipment.

11. An airtightness detection device, characterized in that, It includes: A battery providing module for providing an initial battery; A first gas filling module for subjecting the initial battery to vacuum treatment and filling the initial battery with an inert gas to obtain a pre-inspection battery; A first moving module for placing the pre-inspection battery in a sealed cavity, where the air pressure in the pre-inspection battery is greater than the air pressure in the sealed cavity; A collection module for collecting the parameters of the inert gas in the sealed cavity; A confirmation module for confirming that the pre-inspection battery is a qualified battery when the inert gas parameters meet the preset parameters; and A second moving module for moving the pre-inspection battery out of the sealed cavity and extracting the inert gas in the pre-inspection battery.

12. The airtightness detection device according to claim 11, characterized in that, The airtightness detection device further includes a second gas filling module for injecting a first gas into the sealed cavity to make the air pressure in the sealed cavity meet a second cavity air pressure value.

13. The airtightness detection device according to claim 11 or 12, characterized in that, The airtightness detection device further includes a seal providing module for providing a seal to the initial battery, where in the first state, the seal seals the initial battery; in the second state, the inside of the initial battery is in communication with external equipment.

14. A manufacturing system for a battery cell, characterized in that, It includes the airtightness detection device according to any one of claims 11 to 13.

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