Battery cell airtightness measurement method and system

Abstract

The present disclosure relates to a battery cell airtightness measurement method and system. The measurement method comprises: placing a battery cell to be tested in a first sealed environment, filling the first sealed environment with a reactive gas and a tracer gas, such that the battery cell is in a second sealed environment, and performing an immersion treatment; extracting an environmental medium from the second sealed environment, and measuring the mass content of a target substance in the environmental medium; and when the mass content of the target substance is less than a first preset threshold value, measuring the leakage rate of the tracer gas, wherein the airtightness of the battery cell is determined on the basis of the mass content of the target substance and the leakage rate of the tracer gas. The battery cell airtightness measurement method and system in the embodiments of the present disclosure can improve the efficiency of battery cell airtightness measurement.

Description

Methods and systems for testing the airtightness of individual battery cells Technical Field

[0001] This disclosure relates to the field of batteries, and in particular to a method and system for detecting the airtightness of a single battery cell. Background Technology

[0002] Battery cells are widely used in various electronic devices. During the battery cell manufacturing process, it is necessary to test the airtightness of the assembled battery cells to improve their stability during operation. Therefore, there is an urgent need for a method to test the airtightness of battery cells. Summary of the Invention

[0003] This disclosure provides a method and system for detecting the airtightness of a battery cell, which can improve the efficiency of detecting the airtightness of a battery cell.

[0004] In a first aspect, this disclosure provides a method for detecting the airtightness of a battery cell, comprising: placing the battery cell to be tested in a first sealed environment, filling the first sealed environment with a reactive gas and a tracer gas to place the battery cell in a second sealed environment, and subjecting it to an immersion treatment; extracting an environmental medium from the second sealed environment and detecting the mass content of a target substance in the environmental medium; detecting the leakage rate of the tracer gas when the mass content of the target substance is less than a first preset threshold; wherein the airtightness of the battery cell is determined based on the mass content of the target substance and the leakage rate of the tracer gas.

[0005] In this embodiment, the battery cell under test is placed in a first sealed environment, and a reactive gas and a tracer gas are filled into the first sealed environment to place the battery cell in a second sealed environment for immersion. An ambient medium is extracted from the second sealed environment, and the mass content of the target substance in the ambient medium is detected. If the mass content of the target substance is less than a first preset threshold, the leakage rate of the tracer gas is detected; the airtightness of the battery cell is determined based on the mass content of the target substance and the leakage rate of the tracer gas. By coupling the mass content of the target substance and the leakage rate of the tracer gas to detect the airtightness of the battery cell using the above method, the sensitivity of airtightness detection is improved, thereby improving the efficiency of battery cell airtightness detection.

[0006] In some embodiments, the pressure of the second closed environment is 50-600 kPa.

[0007] By adjusting the pressure of the second sealed environment within the aforementioned range, thorough immersion of the battery cells can be achieved. Even when the battery cells have leaks, the reactive and tracer gases can be introduced into the cells under pressure. Similarly, when the pressure of the second sealed environment is within the aforementioned range, and the battery cells do not have leaks, further damage to the battery cells can be reduced.

[0008] In some embodiments, the humidity of the second enclosed environment is 10%-90% RH.

[0009] By adjusting the humidity of the second sealed environment within the aforementioned range, even when the battery cell has leaks, the substances inside the battery cell can fully react with the reactive gas, thereby improving the accuracy of the battery cell's airtightness detection.

[0010] In some embodiments, the soaking time is 10-420 min.

[0011] This embodiment of the invention, by setting the immersion time within the aforementioned range, allows for thorough immersion of the battery cells. Even in the case of leaks in the battery cells, this allows tracer and reactive gases to enter the cell interior, improving both the accuracy and efficiency of the battery cell airtightness detection. Similarly, when the time in the second sealed environment is within the aforementioned range, further damage to the battery cells can be reduced if no leaks are found.

[0012] In some embodiments, the step of extracting an environmental medium from a second sealed environment and detecting the mass content of the target substance in the environmental medium further includes: determining that the airtightness of the battery cell does not meet the first standard if the mass content of the target substance is greater than or equal to a first preset threshold.

[0013] In some embodiments, the step of extracting an environmental medium from a second sealed environment and detecting the mass content of the target substance in the environmental medium further includes: determining that the airtightness of the battery cell meets a first standard when the mass content of the target substance is less than a first preset threshold.

[0014] In some embodiments, when the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: extracting the ambient medium into a third sealed environment, wherein the pressure of the third sealed environment is 1-120 Pa.

[0015] In some embodiments, when the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: when the leakage rate of the tracer gas is greater than or equal to a second preset threshold, determining that the battery cell does not meet the second standard.

[0016] In some embodiments, when the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: when the leakage rate of the tracer gas is less than a second preset threshold, determining that the battery cell meets the second standard.

[0017] In some embodiments, the pressure of the first sealed environment is 0.5-120 Pa. A pressure within this range can reduce the impact of impurities on the test results, thereby improving the accuracy of the battery cell airtightness test results.

[0018] In some embodiments, the mass content of the target substance in the first enclosed environment is less than 0.001 ppm. This reduces the impact of residual target substances on subsequent test results, thereby further improving the accuracy of the battery cell airtightness test results.

[0019] In some embodiments, the battery cell comprises a sulfide-based material.

[0020] In some embodiments, the reactive gas includes water vapor.

[0021] In some embodiments, the tracer gas includes one or more of helium, hydrogen, nitrogen, and argon.

[0022] Secondly, this disclosure provides a system for detecting the airtightness of a single battery cell, comprising:

[0023] Sealing device: The sealing device includes at least one sealing unit for accommodating the battery cell to be tested;

[0024] Evacuation device: Connected to the sealing device and used to evacuate the sealing device or extract the environmental medium inside the sealing device;

[0025] Gas delivery device: connected to the sealing device and used to inject reactive gas and tracer gas into the sealing device to form a gas mixture within the sealing device;

[0026] Detection device: connected to the sealing device and used to detect the mass content of the target substance and / or the leakage rate of the tracer gas; the detection device includes a target substance detector and a mass spectrometer detector, which are connected in parallel to the sealing device.

[0027] This embodiment of the disclosure couples a target substance detector and a mass spectrometer detector. The target substance detector can perform preliminary detection on the battery cells, while the mass spectrometer detector can perform further detection on the battery cells, thereby improving the detection sensitivity and thus improving the efficiency of battery cell airtightness detection.

[0028] In some embodiments, the air extraction device is connected to the sealing device via a first pipeline, and the first pipeline is provided with a first valve.

[0029] In some embodiments, the air extraction device is connected to the detection device via a second pipeline, and the second pipeline is equipped with a second valve.

[0030] In some embodiments, the gas delivery device is connected to the sealing device via a third pipeline, which is equipped with a third valve.

[0031] In some embodiments, the sealing device includes a first sealing unit, a second sealing unit, and a third sealing unit, which are connected in parallel via pipelines.

[0032] In some embodiments, the sealing unit includes an upper cavity, a lower cavity, and a clamping component located within the sealing unit; the clamping component is used to clamp the battery cell to be tested. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0034] Figure 1 is a flowchart illustrating a method for detecting the airtightness of a battery cell according to some embodiments of this disclosure.

[0035] Figure 2 is a schematic diagram of a battery cell airtightness detection system provided in some embodiments of this disclosure.

[0036] Figure 3 is a schematic diagram of a battery cell airtightness detection system provided in some other embodiments of this disclosure.

[0037] Figure 4 is a schematic diagram of a battery cell air tightness detection system provided in some embodiments of this disclosure.

[0038] Explanation of reference numerals in the attached drawings: 10, sealing device; 20, gas delivery device; 30, gas extraction device; 40, detection device; 41, target substance detector; 42, mass spectrometer detector; 51, first pipeline; 52, second pipeline; 53, third pipeline; 61, first valve; 62, second valve; 63, third valve; 64, fourth valve; 65, fifth valve; 66, sixth valve; 67, seventh valve; 11, first sealing unit; 12, second sealing unit; 13, third sealing unit; 14, upper cavity; 15, lower cavity; 16, clamping component; 17, battery cell; 50, pipeline. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0040] Unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used in the specification of this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this disclosure are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this disclosure are used to distinguish different objects, and not to describe a particular order or hierarchy.

[0041] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0042] Unless otherwise specified, all steps in this disclosure may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0043] In this disclosure, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0044] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0045] In the embodiments of this disclosure, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this disclosure shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this disclosure.

[0046] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0047] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0048] The battery cells in this disclosure may include lithium-ion battery cells, lithium-sulfur battery cells, sodium-ion battery cells, or magnesium-ion battery cells, etc. The battery cells may be cylindrical, flat, cuboid, or other shapes. The packaging methods for the battery cells include, but are not limited to, cylindrical battery cells, prismatic battery cells, and pouch battery cells.

[0049] When solid-state battery cells adopt a pouch structure, it is difficult to use helium mass spectrometry for detection with prismatic or cylindrical structures. In addition, solid-state battery cells produce less gas and do not have gas bladders, making it difficult to test for airtightness.

[0050] In view of this, the present disclosure provides a method for detecting the airtightness of a battery cell. Figure 1 is a schematic flowchart of a method for detecting the airtightness of a battery cell according to some embodiments of the present disclosure. As shown in Figure 1, the detection method includes:

[0051] S10: Place the battery cell to be tested in a first sealed environment, fill the first sealed environment with reactive gas and tracer gas, so that the battery cell is in a second sealed environment and is immersed in it.

[0052] S20: Extract environmental media from the second closed environment and detect the mass content of the target substance in the environmental media;

[0053] S30: When the mass content of the target substance is less than a first preset threshold, the leakage rate of the tracer gas is detected; wherein, the airtightness of the battery cell is determined based on the mass content of the target substance and the leakage rate of the tracer gas.

[0054] The reactive gas and the tracer gas can be mixed and then filled into the first sealed environment, or they can be filled into the first sealed environment separately, as long as the conditions for constructing the second sealed environment can be achieved. For example, the reactive gas and the tracer gas can be mixed and then filled into the first sealed environment, or the reactive gas can be filled into the sealed environment first and then the tracer gas can be filled into the first sealed environment, or the tracer gas can be filled into the first sealed environment first and then the reactive gas can be filled into the first sealed environment.

[0055] It should be noted that, initially, the interior of the battery cell is in a vacuum environment. In the second sealed environment, if there are leaks in the battery cell, the reactive gas and tracer gas will enter the interior of the battery cell through the leaks due to the pressure difference between the inside and outside gases.

[0056] "Leakage rate" refers to the amount of dry gas flowing through a leak at a given temperature per unit time, given the pressure difference across the leak. Its unit is Pa·m³. 3 / s.

[0057] In this embodiment, the battery cell under test is placed in a first sealed environment, and a reactive gas and a tracer gas are filled into the first sealed environment to place the battery cell in a second sealed environment for immersion. An ambient medium is extracted from the second sealed environment, and the mass content of the target substance in the ambient medium is detected. If the mass content of the target substance is less than a first preset threshold, the leakage rate of the tracer gas is detected; the airtightness of the battery cell is determined based on the mass content of the target substance and the leakage rate of the tracer gas. By coupling the mass content of the target substance and the leakage rate of the tracer gas to detect the airtightness of the battery cell using the above method, the sensitivity of airtightness detection is improved, thereby improving the efficiency of battery cell airtightness detection.

[0058] In some embodiments, the pressure of the second enclosed environment can be 50-600 kPa, for example, 50 kPa, 100 kPa, 150 kPa, 200 kPa, 250 kPa, 300 kPa, 350 kPa, 400 kPa, 450 kPa, 500 kPa, 550 kPa, 600 kPa, or any range of two of the above values. It can be selected as 200-500 kPa.

[0059] The pressure in the second enclosed environment refers to absolute pressure. Unless otherwise stated, all pressures mentioned in the embodiments of this disclosure refer to absolute pressure.

[0060] By adjusting the pressure of the second sealed environment within the aforementioned range, thorough immersion of the battery cells can be achieved. Even when the battery cells have leaks, the reactive and tracer gases can be introduced into the cells under pressure. Similarly, when the pressure of the second sealed environment is within the aforementioned range, and the battery cells do not have leaks, further damage to the battery cells can be reduced.

[0061] In some embodiments, the humidity of the second enclosed environment can be 10RH%-90RH%, for example, 10RH%, 20RH%, 30RH%, 40RH%, 50RH%, 60RH%, 70RH%, 80RH%, 90RH%, or any range of two of the above values. Optionally, it can be 45RH%-85RH%.

[0062] The humidity of the second sealed environment can provide an appropriate amount of reactive gas. By adjusting the humidity of the second sealed environment within the above range, even if the battery cell has leaks, the substances inside the battery cell can fully react with the reactive gas, thereby improving the accuracy of the battery cell airtightness test.

[0063] In some embodiments, the soaking time can be 10-420 min, for example, 10 min, 50 min, 100 min, 150 min, 200 min, 250 min, 300 min, 350 min, 400 min, 420 min, or any range of two of the above values. It can also be selected as 60-300 min.

[0064] This embodiment of the invention, by setting the immersion time within the aforementioned range, allows for thorough immersion of the battery cells. Even in the case of leaks in the battery cells, this allows tracer and reactive gases to enter the cell interior, improving both the accuracy and efficiency of the battery cell airtightness detection. Similarly, when the time in the second sealed environment is within the aforementioned range, further damage to the battery cells can be reduced if no leaks are found.

[0065] In some embodiments, the step of extracting an environmental medium from a second sealed environment and detecting the mass content of the target substance in the environmental medium further includes: determining that the airtightness of the battery cell does not meet the first standard if the mass content of the target substance is greater than or equal to a first preset threshold.

[0066] In this embodiment of the disclosure, if it is determined that a single battery cell does not meet the first standard, it is necessary to stop testing the single battery cell.

[0067] In some embodiments, the first preset threshold can be 0.05-0.5ppm, for example, it can be 0.05ppm, 0.1ppm, 0.2ppm, 0.3ppm, 0.4ppm, 0.5ppm, or a range consisting of any two of the above values.

[0068] The first preset threshold is set based on the size of the leak. This allows the mass content of the target material to more accurately reflect the size of the leak in the battery cell, further improving the accuracy of the battery cell airtightness test results.

[0069] The detection of target substances in the environmental medium of the second sealed environment can be a form of detection to check for large leaks in individual battery cells. For example, when a large leak exists in a battery cell, the equivalent diameter of the leak hole can be greater than or equal to 10 μm and less than 200 μm.

[0070] In the event of a large leak in a single battery cell, after immersion treatment, reactive and tracer gases will enter the cell through the leak. The reactive gases will react with substances within the cell to generate the target substance. The ambient medium is then extracted from the secondary sealed environment surrounding the battery cell, and the target substance is extracted from within the cell.

[0071] In some embodiments, the step of extracting an environmental medium from a second sealed environment and detecting the mass content of the target substance in the environmental medium further includes: determining that the airtightness of the battery cell meets a first standard when the mass content of the target substance is less than a first preset threshold.

[0072] In some embodiments, when the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: extracting the ambient medium into a third sealed environment, wherein the pressure of the third sealed environment can be 1-120 Pa, for example, 1 Pa, 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa, 60 Pa, 70 Pa, 80 Pa, 90 Pa, 100 Pa, 110 Pa, 120 Pa, or any range of two of the above values.

[0073] By setting the pressure of the third sealed environment within the aforementioned range, the conditions of the third sealed environment can meet the requirements for subsequent detection of the leakage rate of the tracer gas.

[0074] In the absence of large leaks in individual battery cells, the leakage rate of the tracer gas is detected to determine whether micro-leaks exist in the individual cells. For example, when micro-leaks exist in individual battery cells, the equivalent diameter of the leak can be greater than or equal to 0.5 μm and less than 10 μm.

[0075] Continue extracting the ambient medium until the pressure of the third environment reaches 1-120 Pa. The tracer gas outside the battery cell will be extracted before any tracer gas that may be inside the battery cell. In the case of micro-leakage in the battery cell, the mass content of the tracer gas outside the battery cell is much lower than that inside. Continue evacuating the cavity; the tracer gas inside the battery cell will be extracted as the vacuum level continues to decrease.

[0076] In some embodiments, when the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: when the leakage rate of the tracer gas is greater than or equal to a second preset threshold, determining that the battery cell does not meet the second standard.

[0077] In some embodiments, when the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: when the leakage rate of the tracer gas is less than a second preset threshold, determining that the battery cell meets the second standard.

[0078] For example, the second preset threshold can be 0.5 × 10⁻⁶. -6 -2.0×10 -6 Pa·m 3 / s, for example, can be 0.5×10 -6 Pa·m 3 / s, 1.0×10 -6 Pa·m 3 / s, 1.5×10 -6 Pa·m 3 / s, 2.0×10 -6 Pa·m 3 / s, or a range consisting of any two of the above values.

[0079] The second standard is used to determine whether there are smaller leaks in the battery cells. That is, the leakage rate of the tracer gas can reflect whether there are micro-leaks in the battery cells.

[0080] In some embodiments, the pressure of the first sealed environment can be 0.5-120 Pa, for example, 0.5 Pa, 1 Pa, 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa, 60 Pa, 70 Pa, 80 Pa, 90 Pa, 100 Pa, 110 Pa, 120 Pa, or any range of two of the above values. When the pressure of the first sealed environment is within the above range, the influence of impurities on the test results can be reduced, thereby improving the accuracy of the battery cell airtightness test results.

[0081] In some embodiments, the mass content of the target substance in the first enclosed environment is less than 0.001 ppm.

[0082] When the mass content of the target substance in the first closed environment is within the above range, the impact of residual target substances on subsequent test results can be reduced, thereby further improving the accuracy of the battery cell airtightness test results.

[0083] In some embodiments, the battery cell may include a sulfide-based material.

[0084] The sulfide-based material can be one or more of the following: sulfide-based solid electrolyte, sulfide-polymer blend, sulfide-based active material in or on the electrode, or sulfide-based cathode electrolyte or anolyte in or on the electrode composite material.

[0085] In some embodiments, the reactive gas may include water vapor.

[0086] In a battery cell, sulfide-based materials react chemically with reactive gases. For example, sulfide-based materials react with water vapor to generate hydrogen sulfide gas, and the target substance in this case is hydrogen sulfide gas.

[0087] In some embodiments, the tracer gas may include one or more of helium, hydrogen, nitrogen, and argon.

[0088] In some embodiments, the tracer gas may include one or more of the following: a mixture of helium and nitrogen, a mixture of hydrogen and nitrogen, and a mixture of argon and nitrogen.

[0089] In some embodiments, the nitrogen volume fraction in the tracer gas is 90%-95%.

[0090] [Battery Cell Airtightness Testing System]

[0091] Figure 2 is a schematic diagram of a battery cell airtightness detection system provided in some embodiments of this disclosure.

[0092] As shown in Figure 2, the battery cell airtightness detection system includes:

[0093] Sealing device 10: Sealing device 10 includes at least one sealing unit for accommodating the battery cell to be tested;

[0094] Evacuation device 30: connected to the sealing device 10 and used to evacuate the sealing device 10 or extract the environmental medium inside the sealing device 10;

[0095] Gas delivery device 20: connected to the sealing device 10 and used to inject reactive gas and tracer gas into the sealing device 10 to form a gas mixture within the sealing device 10;

[0096] Detection device 40: connected to the sealing device 10 and used to detect the mass content of the target substance and / or the leakage rate of the tracer gas; the detection device 40 includes a target substance detector 41 and a mass spectrometer detector 42, which are connected in parallel to the sealing device 10.

[0097] This embodiment of the disclosure couples a target substance detector and a mass spectrometer detector. The target substance detector can perform preliminary detection on the battery cells, while the mass spectrometer detector can perform further detection on the battery cells, thereby improving the detection sensitivity and thus improving the efficiency of battery cell airtightness detection.

[0098] The target substance detector 41 can be used to detect the mass content of the target substance, and the mass spectrometer detector 42 can be used to detect the leakage rate of the tracer gas. A seventh valve 67 is provided between the target substance detector 41 and the mass spectrometer detector 42. The opening and closing of the seventh valve 67 is used to realize the separate detection of the target substance and the tracer gas in the environmental medium.

[0099] The leak rate of the tracer gas was determined using a mass spectrometer detector, and it satisfied the condition shown in equation (1):

[0100] In equation (1), R is the magnetic deflection radius, U is the accelerating voltage, B is the magnetic induction intensity, and m / q is the mass-to-charge ratio of the tracer gas. According to the above equation, the detection of different tracer gases can be achieved by adjusting the accelerating voltage.

[0101] In some embodiments, the pumping device may be a vacuum pump.

[0102] Figure 3 is a schematic diagram of a battery cell airtightness detection system provided in some other embodiments of this disclosure.

[0103] As shown in Figure 3, in some embodiments, the air extraction device 30 can be connected to the sealing device 10 through the first pipeline 51, and the first pipeline 51 is provided with a first valve 61.

[0104] In some embodiments, the air extraction device 30 can be connected to the detection device 40 via a second pipe 52, and the second pipe 52 is provided with a second valve 62.

[0105] In some embodiments, the gas delivery device 20 can be connected to the sealing device 10 via a third pipeline 53, which is provided with a third valve 63.

[0106] The first valve, second valve, and third valve described above are used to control the opening and closing of the first pipeline, the second pipeline, and the third pipeline, respectively. For example, the first valve, second valve, and third valve can be solenoid valves.

[0107] The sealing device can provide a stable sealing environment for the battery cell under test.

[0108] Please continue to refer to Figure 3. In some embodiments, the sealing device 10 may include a first sealing unit 11, a second sealing unit 12, and a third sealing unit 13, which are connected in parallel via pipelines.

[0109] The above-mentioned sealing units are connected in parallel, which can realize the simultaneous vacuuming of multiple sealing units, thereby improving the efficiency of battery cell airtightness testing.

[0110] In some embodiments, multiple sealing units are connected to the first pipeline 51 via branch pipes, and multiple sealing units are connected to the third pipeline 53 via branch pipes. There can be multiple branch pipes, each corresponding to one of the multiple sealing units. For example, each branch pipe is equipped with a fourth valve 64, a fifth valve 65, and a sixth valve 66. Each sealing unit may also be equipped with a pressure gauge and a hygrometer (not shown) to detect the pressure and humidity of each sealing unit.

[0111] Figure 4 is a schematic diagram of a battery cell air tightness detection system provided in some embodiments of this disclosure.

[0112] Please refer to Figure 4. In some embodiments, the sealing unit may include an upper cavity 14, a lower cavity 15, and a clamping member 16 located within the sealing unit. The upper cavity 14 and the lower cavity 15 together constitute a sealed cavity. Each cavity is connected to the target substance detector 41 and the mass spectrometer detector 42 via conduits 50, and each cavity is also connected to the gas delivery device 20 via conduits 50.

[0113] In some embodiments, the clamping member 16 is disposed in the lower cavity 15 and is used to clamp the battery cell 17. Exemplarily, the clamping member 16 may be a clamp.

[0114] In some embodiments, a plurality of clamping members 16 may be provided in the sealing unit, the plurality of clamping members 16 being spaced apart, and each clamping member 16 being used to clamp a single battery cell.

[0115] By fixing multiple battery cells one by one with multiple clamping components, the stability of the system can be improved when performing airtightness testing on battery cells.

[0116] The shape and size of the clamping component match the shape and size of the battery cell. For example, the clamping component can be a cuboid, cube, or cylinder, and the corresponding upper and lower cavities are also cuboids, cubes, or cylinders of matching size. One or more battery cells can be placed in the cavity.

[0117] In some embodiments, a battery cell may include a sulfide solid-state battery cell, and exemplarily, a sulfide solid-state battery cell may be a pouch sulfide solid-state battery cell.

[0118] Sulfur in sulfide solid-state battery cells can be present in the solid electrolyte, or in the positive or negative electrode materials.

[0119] In some embodiments, sulfur may be present in the solid electrolyte. The sulfide solid electrolyte is not limited to a specific component and may include one or more of crystalline solid electrolytes, amorphous solid electrolytes (glassy solid electrolytes), or glass-ceramic solid electrolytes.

[0120] In some embodiments, the sulfide solid electrolyte may include sulfide-germanium sulfide, binary sulfide, and ternary sulfide.

[0121] In some embodiments, sulfide of the silver-germanium type may include sulfides with the chemical formula Li 6±s P 1-j A j S 5±s- t B t X 1±sThe material has the following properties: 0≤j<1, 0≤t<1, 0≤s<1, A includes one or more elements from Ge, Si, Sn and Sb, B includes one or more elements from O, Se and Te, and X includes one or more elements from Cl, Br, I and F.

[0122] The solid-state battery cells mentioned in the embodiments of this disclosure can independently perform the functions of charging and discharging.

[0123] It should be noted that the airtightness testing method and system provided in this disclosure can be used not only to test the airtightness of individual battery cells, but also to test the airtightness of battery packs, battery modules, etc.

[0124] The technical solutions of this disclosure are described below through some specific embodiments.

[0125] After placing the soft-pack sulfide solid-state battery cell in the clamp of the lower cavity, it is lifted upwards and sealed with the upper cavity. The cavities of the first sealing unit, the second sealing unit, and the third sealing unit are evacuated to a first sealed environment, so that the absolute pressure in each cavity is 20Pa and the background value of hydrogen sulfide in the cavity is 0.0005ppm, in order to reduce the influence of residual gas in the cavity.

[0126] After vacuuming, tracer gas helium and nitrogen mixture with a volume ratio of 1:9 and reactive gas water vapor are injected into each chamber to place the soft-pack sulfide solid-state battery cell in a second sealed environment and immerse it. The humidity of the second sealed environment is 85% RH, the pressure of the second sealed environment is 500 kPa, and the immersion time is 60 min.

[0127] After the soaking treatment is completed, the environmental medium is extracted and the mass content of the target substance H2S is detected simultaneously. If the mass content of H2S is ≥0.1pmm, the soft-pack sulfide solid-state battery cell is determined to be a defective product with a large leak. At this time, the soft-pack sulfide solid-state battery cell is removed and the testing is stopped.

[0128] When the H2S mass content is <0.1 pmm, continue sampling the ambient medium until the pressure inside the chamber reaches 10 Pa. Then, use helium mass spectrometry to quantitatively detect the tracer gas leak rate. If the tracer gas leak rate is ≥1.0 × 10⁻⁶, the leak rate is considered within the specified range. -6 Pa·m 3 If the leakage rate is within a certain range (e.g., / s), the sulfide solid-state battery is determined to be a defective product with slight leakage; otherwise, it is considered a good product. The soft-pack sulfide solid-state battery cells within the first, second, and third sealing units are then tested sequentially using the method described above.

[0129] The battery cell airtightness detection method and system of the present disclosure can realize quantitative detection of battery cell airtightness, reduce the probability of over-detection in battery cell airtightness detection (the probability of over-detection is less than 0.5%), and achieve zero missed detection in battery cell airtightness detection, thereby improving the efficiency of battery cell airtightness detection.

[0130] Although this disclosure has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this disclosure. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This disclosure is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for detecting the airtightness of a single battery cell, characterized in that, include: The battery cell to be tested is placed in a first sealed environment, and a reactive gas and a tracer gas are filled into the first sealed environment to place the battery cell in a second sealed environment for immersion treatment. An environmental medium is extracted from the second sealed environment, and the mass content of the target substance in the environmental medium is detected. When the mass content of the target substance is less than a first preset threshold, the leakage rate of the tracer gas is detected; wherein, the airtightness of the battery cell is determined based on the mass content of the target substance and the leakage rate of the tracer gas.

2. The detection method according to claim 1, characterized in that, The pressure of the second sealed environment is 50-600 kPa; and / or, The humidity of the second enclosed environment is 10%-90% RH.

3. The detection method according to claim 1 or 2, characterized in that, The soaking time is 10-420 min.

4. The detection method according to any one of claims 1-3, characterized in that, The step of extracting environmental media from the second sealed environment and detecting the mass content of the target substance in the environmental media further includes: If the mass content of the target substance is greater than or equal to a first preset threshold, the airtightness of the battery cell is determined to not meet the first standard; and / or, If the mass content of the target substance is less than a first preset threshold, the airtightness of the battery cell is determined to meet the first standard.

5. The detection method according to any one of claims 1-4, characterized in that, When the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: The environmental medium is extracted into a third sealed environment, the pressure of which is 1-120 Pa.

6. The detection method according to any one of claims 1-5, characterized in that, When the mass content of the target substance is less than a first preset threshold, the step of detecting the leakage rate of the tracer gas further includes: If the leakage rate of the tracer gas is greater than or equal to a second preset threshold, the battery cell is determined to not meet the second criterion; and / or, If the leakage rate of the tracer gas is less than a second preset threshold, the battery cell is determined to meet the second standard.

7. The detection method according to any one of claims 1-6, characterized in that, The pressure of the first sealed environment is 0.5-120 Pa; and / or, The mass content of the target substance in the first closed environment is less than 0.001 ppm.

8. The detection method according to any one of claims 1-7, characterized in that, The battery cell comprises a sulfide-based material.

9. The detection method according to any one of claims 1-8, characterized in that, The reactive gas includes water vapor; and / or, The tracer gas includes one or more of helium, hydrogen, nitrogen, and argon.

10. A system for detecting the airtightness of a single battery cell, characterized in that, include: Sealing device: The sealing device includes at least one sealing unit for accommodating the battery cell to be tested; Vacuum extraction device: connected to the sealing device and used to evacuate the sealing device or extract the environmental medium inside the sealing device; Gas delivery device: connected to the sealing device and used to inject reactive gas and tracer gas into the sealing device to form a gas mixture within the sealing device; Detection device: connected to the sealing device and used to detect the mass content of the target substance and / or the leakage rate of the tracer gas; the detection device includes a target substance detector and a mass spectrometer detector, which are connected in parallel to the sealing device.

11. The detection system according to claim 10, characterized in that, The air extraction device is connected to the sealing device via a first pipeline, and the first pipeline is equipped with a first valve; and / or The air extraction device is connected to the detection device through a second pipeline, and the second pipeline is equipped with a second valve.

12. The detection system according to claim 10 or 11, characterized in that, The gas delivery device is connected to the sealing device via a third pipeline, and the third pipeline is equipped with a third valve.

13. The detection system according to any one of claims 10-12, characterized in that, The sealing device includes a first sealing unit, a second sealing unit, and a third sealing unit, which are connected in parallel via pipelines.

14. The detection system according to any one of claims 10-13, characterized in that, The sealing unit includes an upper cavity, a lower cavity, and a clamping component located within the sealing unit; The clamping component is used to clamp the battery cell to be tested.

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