Air tightness detection method, device, equipment, storage medium and program product

Abstract

The invention relates to an air tightness detection method, device and equipment, a storage medium and a program product. The method comprises the following steps: acquiring an actual concentration curve of each detection position on a battery pack in a process of filling tracer gas into the battery pack; the actual concentration curve comprises time-varying data of the concentration of the tracer gas in the gas replacement process; determining an air tightness detection result of each detection position according to the reference concentration curve and the actual concentration curve of each detection position; the reference concentration curve comprises time-varying data of the concentration of the tracer gas calculated by adopting a flow field model in advance, and the gas tightness detection result is used for representing whether the tracer gas leaks at the detection position or not. According to the invention, the air tightness detection efficiency can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of airtightness detection, and in particular to an airtightness detection method, device, equipment, storage medium and program product. Background Art

[0002] With the development of new energy technology, battery packs have been applied to many fields. In order to improve the safety performance of battery packs, it is necessary to conduct multiple tests on battery packs, among which air tightness test is a relatively important test.

[0003] At present, air tightness testing usually involves filling the battery pack with tracer gas, replacing the air in the battery pack with the tracer gas, and then detecting whether there is tracer gas leakage at multiple locations on the battery pack body. Since it takes a long time for the tracer gas to replace the air, the air tightness testing efficiency is low. Summary of the invention

[0004] Based on the above problems, the present application provides an airtightness detection method, device, equipment, storage medium and program product, which can improve the efficiency of airtightness detection.

[0005] In a first aspect, the present application provides an airtightness detection method, the method comprising: in the process of charging a battery pack with tracer gas, obtaining an actual concentration curve at each detection position on the battery pack; the actual concentration curve includes data on the concentration variation of the tracer gas over time during the gas replacement process; determining the airtightness detection result of each detection position based on the reference concentration curve and the actual concentration curve of each detection position; the reference concentration curve includes data on the concentration variation of the tracer gas over time obtained by pre-calculating using a flow field model, and the airtightness detection result is used to characterize whether there is a tracer gas leakage at the detection position.

[0006] In the technical solution of the embodiment of the present application, a reference concentration curve is obtained by pre-simulation. Since the actual concentration curve and the reference concentration curve are both data on the concentration change of the tracer gas over time, they reflect the change in gas concentration at the detection position during the entire gas replacement process. Therefore, there is no need to wait for the tracer gas to replace the air in the battery pack and reach a equilibrium state before determining whether there is a tracer gas leakage. Therefore, the air-tightness detection time can be shortened, thereby improving the efficiency of the air-tightness detection.

[0007] In some embodiments, the air tightness test result of each detection position is determined according to the reference concentration curve and the actual concentration curve of each detection position, including: for each detection position, respectively determining the first gas concentration corresponding to the preset detection time in the actual concentration curve and the second gas concentration corresponding to the preset detection time in the reference concentration curve; when the first gas concentration is greater than the second gas concentration, determining that the air tightness test result indicates that there is a tracer gas leak at the detection position. In the technical solution of the embodiment of the present application, the reference concentration curve is used to perform air tightness testing in a non-equilibrium state of the gas replacement process, which can shorten the detection time and improve the detection efficiency.

[0008] In some embodiments, the method further includes: obtaining a structural model and simulation conditions of the battery pack respectively; simulating the gas flow state using the structural model, simulation conditions and flow field model to obtain a reference concentration curve for each detection position. In the technical solution of the embodiment of the present application, the reference concentration curve can be used to perform airtightness detection in a non-equilibrium state during the gas replacement process, which can shorten the detection time and improve the detection efficiency.

[0009] In some embodiments, the simulation conditions include multiple replacement modes, and the replacement modes include charging port information and exhaust port information; the gas flow state is simulated using the structural model, simulation conditions and flow field model to obtain a reference concentration curve for each detection position, including: under different replacement modes, the flow field model is used to simulate the gas flow state at each preset position on the structural model, and the reference concentration curve for each detection position under each replacement mode is obtained; wherein the preset position corresponds to the detection position one by one. In the technical solution of the embodiment of the present application, the reference concentration curve can be simulated for battery packs of different structures and different replacement modes, so that in actual detection, a suitable reference concentration curve can be selected according to the actual situation to determine whether there is a tracer gas leak.

[0010] In some embodiments, the method further includes: using a flow field model to simulate the flow state of gas in the structural model under different replacement modes, and obtaining the first concentration uniformity of the tracer gas in the battery pack and the first replacement time required for the gas replacement to reach an equilibrium state; determining the optimal replacement mode from multiple replacement modes according to the first concentration uniformity and the first replacement time; the optimal replacement mode is used to optimize the detection structure. In the technical solution of the embodiment of the present application, the flow field model is used for simulation to find a better replacement mode, thereby effectively improving the gas replacement effect and the accuracy of airtightness detection; and effectively improving the gas replacement efficiency and the efficiency of airtightness detection.

[0011] In some embodiments, the simulation conditions include multiple tracheal lengths; the gas flow state is simulated using the structural model, simulation conditions and flow field model to obtain a reference concentration curve for each detection position, including: under different tracheal lengths of the target replacement method, the flow field model is used to simulate the gas flow state at each preset position on the structural model to obtain a reference concentration curve for each detection position under each tracheal length; wherein the preset position corresponds to the detection position one by one. In the technical solution of the embodiment of the present application, a reference concentration curve can be simulated for various tracheal lengths, so that in actual detection, a suitable reference concentration curve can be selected according to the actual situation to determine whether there is a tracer gas leak.

[0012] In some embodiments, the method further includes: using a flow field model to simulate the flow state of gas in the structural model under different air tube lengths of the target replacement mode, and obtaining the second concentration uniformity of the tracer gas in the battery pack and the second replacement time required for the gas replacement to reach an equilibrium state; determining the optimal air tube length from multiple air tube lengths according to the second concentration uniformity and the second replacement time; the optimal air tube length is used to optimize the detection structure. In the technical solution of the embodiment of the present application, the flow field model is used for simulation to find a more optimal air tube length, thereby effectively improving the gas replacement efficiency and the efficiency of airtightness detection.

[0013] In a second aspect, the present application also provides an airtightness detection device, the device comprising:

[0014] An actual concentration acquisition module is used to obtain an actual concentration curve of each detection position on the battery pack during the process of charging the tracer gas into the battery pack; the actual concentration curve includes data on the concentration change of the tracer gas over time during the gas replacement process;

[0015] The airtightness detection module is used to determine the airtightness detection result of each detection position according to the reference concentration curve and the actual concentration curve of each detection position; the reference concentration curve includes the data of the concentration change of the tracer gas over time obtained by pre-simulating the flow field model, and the airtightness detection result is used to characterize whether there is a tracer gas leakage at the detection position.

[0016] In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the method of the first aspect when executing the computer program.

[0017] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method of the first aspect is implemented.

[0018] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which implements the method of the first aspect when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the optional embodiments below. The accompanying drawings are only used for the purpose of illustrating the optional embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0020] Figure 1 A schematic diagram of an application environment of an airtightness detection method according to an embodiment of the present application;

[0021] Figure 2 It is a flow chart of an airtightness detection method according to an embodiment of the present application;

[0022] Figure 3 is a concentration curve diagram of an embodiment of the present application;

[0023] Figure 4 It is a flow chart of the airtightness detection step of an embodiment of the present application;

[0024] Figure 5 It is a schematic flow chart of simulation steps using a flow field model according to an embodiment of the present application;

[0025] Figure 6a is a schematic diagram of a structural model of an embodiment of the present application;

[0026] Figure 6b It is a partial enlarged view of an embodiment of the present application;

[0027] Figure 6c is a schematic diagram of a replacement method of an embodiment of the present application;

[0028] Figure 7 It is a schematic flow chart of simulation steps using a flow field model according to an embodiment of the present application;

[0029] Figure 8 It is a schematic flow chart of simulation steps using a flow field model according to an embodiment of the present application;

[0030] Fig. 9 is a structural block diagram of an airtightness detection device according to an embodiment of the present application;

[0031] Fig.10 is a structural block diagram of an airtightness detection device according to an embodiment of the present application;

[0032] Fig.11 It is a diagram of the internal structure of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0035] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0036] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0038] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0039] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of 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 the present application can be understood according to the specific circumstances.

[0040] With the development of new energy technologies, battery packs have been applied to many fields. In order to improve the safety performance of battery packs, multiple tests need to be performed on the battery packs, among which air tightness test is a relatively important test. At present, air tightness test usually involves filling the battery pack with tracer gas, using the tracer gas to replace the air in the battery pack, and then detecting whether there is tracer gas leakage at multiple locations on the battery pack body. Normally, air tightness test is performed after the tracer gas has replaced the air inside the battery pack and reached a balanced state. However, since it takes a long time for the tracer gas to replace the air, the efficiency of air tightness test is low.

[0041] The embodiment of the present application provides an air tightness detection method, which uses a flow field model to simulate a reference concentration curve in advance, and then obtains the actual concentration curve of each detection position on the battery pack during the process of filling the tracer gas into the battery pack; and then determines the air tightness detection result of each detection position based on the reference concentration curve and the actual concentration curve of each detection position. Since the actual concentration curve and the reference concentration curve are both data on the concentration change of the tracer gas over time, reflecting the change of gas concentration at the detection position during the entire gas replacement process, there is no need to wait for the tracer gas to replace the air in the battery pack and reach a balanced state before judging whether there is a tracer gas leak, so the air tightness detection time can be shortened, thereby improving the efficiency of air tightness detection.

[0042] The airtightness detection method provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. The application environment may include a battery pack 101, a battery pack detection system 102 and a computer device 103, wherein the battery pack detection system 102 can communicate with the computer device 103 through a network. The above-mentioned battery pack can be used in electrical devices such as vehicles, ships or aircraft, but is not limited to it. The above-mentioned battery pack detection system 102 may include but is not limited to a gas transmission structure and a gas sensor, wherein the gas transmission structure can be fixedly connected to the battery pack 101, so as to fill the battery pack with tracer gas, and transmit the gas at the detection position of the battery pack to the gas sensor. For example, the gas transmission structure includes an inflation tube for inflating the battery pack, a cover box at the detection position and an exhaust pipe arranged on the cover box. It should be noted that the gas transmission structure is not limited to the above description and can be set according to actual conditions. The gas sensor can transmit the collected data to the computer device 103 through the network. The above-mentioned computer device may be, but is not limited to, various personal computers, laptops, smart phones and tablet computers.

[0043] According to some embodiments of the present application, referring to Figure 2 , provides an airtightness detection method, which is applied to Figure 1 Taking the computer device in the example as an example, the following steps may be included:

[0044] Step 201 : in the process of charging the battery pack with tracer gas, obtaining the actual concentration curve of each detection position on the battery pack.

[0045] The tracer gas may include hydrogen or a mixture of hydrogen and nitrogen. The actual concentration curve includes data on the concentration of the tracer gas changing with time during the gas replacement process.

[0046] In the process of charging the battery pack with tracer gas, multiple gas sensors of the battery pack detection system collect data on the gas concentration at each detection position on the battery pack, and transmit the collected concentration data to the computer device in real time. The computer device receives the concentration data transmitted in real time by multiple gas sensors, and plots the concentration data collected by each gas sensor into a curve in chronological order to obtain the actual concentration curve of each detection position on the battery pack.

[0047] Step 202: Determine the air tightness test result of each test position according to the reference concentration curve and the actual concentration curve of each test position.

[0048] The reference concentration curve includes the data of the concentration change of the tracer gas over time obtained by pre-simulating the flow field model. The flow field model is a model established based on fluid mechanics and used to simulate the flow state of the gas. The flow field model may include a turbulence model, an eddy flow model, etc. The airtightness test result is used to characterize whether there is a tracer gas leak at the test location.

[0049] The computer equipment can use the flow field model to simulate the flow state of the tracer gas in advance. For example, the flow field model is used to simulate the tracer gas entering from the inflation port of the battery pack, flowing inside the battery pack, and finally being discharged from the exhaust port of the battery pack. It can be understood that during the replacement process, the concentration of the tracer gas at each detection position on the battery pack will change over time. In addition, since the gas concentration at the inflation port is higher and the gas concentration at the exhaust port is lower at the initial stage of gas replacement, the gas concentration at different detection positions is different at the same detection moment. As time goes by, the tracer gas gradually replaces the air inside the battery pack. After the gas replacement reaches a state of equilibrium, the gas concentration at the inflation port is close to the gas concentration at the exhaust port. Therefore, the gas concentrations at different detection positions are also relatively close.

[0050] After simulation using the flow field model, the concentration data of the tracer gas at multiple detection times at each detection position can be obtained. The concentration data can be plotted into a curve in chronological order to obtain a reference concentration curve for each detection position.

[0051] In the actual detection process, for each detection position, the actual concentration curve of the detection position is first obtained, and then the actual concentration curve is compared with the reference concentration curve obtained by pre-simulation to obtain the air tightness detection result of whether there is tracer gas leakage at the detection position. Figure 3 , the horizontal axis is time, the vertical axis is the concentration of the tracer gas, the solid line is the reference concentration curve, and the dotted line is the actual concentration curve. In the figure, if the actual concentration curve is higher than the reference concentration curve, the air tightness test result indicating that there is a tracer gas leak at the test location is obtained; if the actual concentration curve is lower than the reference concentration curve, the air tightness test result indicating that there is no tracer gas leak at the test location is obtained.

[0052] In the above embodiment, in the process of charging the battery pack with tracer gas, the actual concentration curve of each detection position on the battery pack is obtained; according to the reference concentration curve and the actual concentration curve of each detection position, the air tightness test result of each detection position is determined. In the technical solution of the embodiment of the present application, the reference concentration curve is simulated in advance. Since the actual concentration curve and the reference concentration curve are both data of the concentration change of the tracer gas over time, reflecting the change of gas concentration at the detection position during the entire gas replacement process, there is no need to wait for the tracer gas to replace the air in the battery pack and reach a balanced state before judging whether there is a tracer gas leak. Therefore, the air tightness test time can be shortened, thereby improving the efficiency of the air tightness test.

[0053] According to some embodiments of the present application, referring to Figure 4 After the actual concentration curve is obtained, the process of determining the airtightness test result of each test position according to the reference concentration curve and the actual concentration curve of each test position may include the following steps:

[0054] Step 301 : for each detection position, respectively determine the first gas concentration corresponding to the preset detection time in the actual concentration curve and the second gas concentration corresponding to the preset detection time in the reference concentration curve.

[0055] For each detection position, the gas concentration corresponding to the same preset detection time is determined in the actual concentration curve and the reference concentration curve, respectively, to obtain a first gas concentration in the actual concentration curve and a second gas concentration in the reference concentration curve.

[0056] by Figure 3 For example, the first gas concentration corresponding to the preset detection time of 30s in the actual concentration curve 1 is 0.0006, the first gas concentration corresponding to the preset detection time of 30s in the actual concentration curve 2 is 0.0004, and the second gas concentration corresponding to the preset detection time of 30s in the reference concentration curve is 0.0005.

[0057] Step 302 : when the first gas concentration is greater than the second gas concentration, determine that the air tightness test result indicates that there is a tracer gas leak at the test location.

[0058] If the first gas concentration curve is greater than the second gas concentration curve, it indicates that there is more tracer gas at the detection position, so it can be determined that there is a tracer gas leak at the detection position.

[0059] Still Figure 3 For example, if the first gas concentration corresponding to the preset detection time of 30s in the actual concentration curve 1 is greater than the second gas concentration corresponding to the preset detection time of 30s in the reference concentration curve, it can be determined that there is a tracer gas leak at the detection position corresponding to the actual concentration curve 1. If the first gas concentration corresponding to the preset detection time of 30s in the actual concentration curve 2 is less than the second gas concentration corresponding to the preset detection time of 30s in the reference concentration curve, it can be determined that there is no tracer gas leak at the detection position corresponding to the actual concentration curve 2.

[0060] In the above embodiment, for each detection position, the first gas concentration corresponding to the preset detection time in the actual concentration curve and the second gas concentration corresponding to the preset detection time in the reference concentration curve are determined respectively; when the first gas concentration is greater than the second gas concentration, it is determined that the air tightness detection result indicates that there is a tracer gas leak at the detection position. In the technical solution of the embodiment of the present application, the reference concentration curve is used to perform air tightness detection in a non-equilibrium state of the gas replacement process, which can shorten the detection time and improve the detection efficiency.

[0061] Before conducting air tightness testing, the flow field model is used to simulate and determine the reference concentration curve for each test position. Figure 5 The simulation process of the embodiment of the present application may include the following steps:

[0062] Step 401, respectively obtain the structural model and simulation conditions of the battery pack.

[0063] The structural model may include structural information of the battery pack, which may include size information such as length, width, height, etc. of the battery pack and spatial division information inside the battery pack. The structural model may also include information such as Figure 6a In the model diagram shown, 11 is an air filling pipe, and 12 is an exhaust pipe; Figure 6b for Figure 6a The enlarged view of the part in the dotted circle, 13 is the air intake pipe, and 14 is the leak on the surface of the battery pack. The simulation conditions may include the type of tracer gas, the charging and exhausting method of the tracer gas, etc. For example, the simulation conditions include that the filling gas is a mixture of 5% hydrogen and 95% nitrogen by volume. It should be noted that the simulation conditions include but are not limited to the above description and can be set according to actual conditions.

[0064] In one embodiment, the tester first uses structural drawing software to establish a structural model of the battery pack and makes corresponding annotations in the structural model; then the drawn structural model is imported into a computer device to be simulated, and the computer device can obtain the structural model of the battery pack. In another embodiment, the tester inputs the structural information of the battery pack into the computer device, and the computer device determines the structural model of the battery pack based on the structural information.

[0065] Likewise, the tester can input simulation conditions such as gas composition into the computer device, and the computer device can obtain the simulation conditions.

[0066] Step 402, using the structural model, simulation conditions and flow field model to simulate the gas flow state, and obtain the reference concentration curve of each detection position.

[0067] After obtaining the structural model and simulation conditions, the space where the gas flows and the detection position where the gas leakage may occur can be determined based on the structural model; then, the flow field model is used to simulate the flow state of the gas in the space and the state of the gas leakage from the detection position. During the simulation process, the simulation conditions obtained previously are used as boundary conditions.

[0068] For example, the length, width, and height of the gas flow space are first determined based on the structural model, and the partition positions within the space and the positions where gas leakage may occur are determined. Then, a mixture of 5% hydrogen and 95% nitrogen with a volume fraction of 5% is simulated to be filled into the battery pack, and the flow state of the mixture in the above space is calculated by the flow field model, and the concentration of the mixture at the detection position is calculated. Finally, the concentrations at each detection position are plotted into a reference concentration curve in chronological order.

[0069] In the above embodiment, the structural model and simulation conditions of the battery pack are obtained respectively; the gas flow state is simulated using the structural model, simulation conditions and flow field model to obtain the reference concentration curve at each detection position. In the technical solution of the embodiment of the present application, the structural model and simulation conditions are used as the boundary conditions for the flow field simulation, which can make the simulation closer to the actual situation, thereby making the reference concentration curve more referenceable.

[0070] According to some embodiments of the present application, the above-mentioned simulation conditions include multiple replacement modes, and the replacement modes include inflation port information and exhaust port information. The inflation port information may include the layout of the inflation port, such as the number and position of the inflation port, and may also include the pressure of the inflation port. The exhaust port information may include the layout of the exhaust port, such as the number and position of the exhaust port, and may also include the pressure of the exhaust port. It can be understood that different layout modes of inflation ports and exhaust ports, as well as different pressures, can constitute different replacement modes. The above-mentioned process of simulating the gas flow state using the structural model, simulation conditions and flow field model to obtain the reference concentration curve of each detection position may include: under different replacement modes, using the flow field model to simulate the flow state of the gas at each preset position on the structural model, and obtaining the reference concentration curve of each detection position under each replacement mode.

[0071] The above-mentioned preset positions are positions where the tracer gas leakage is likely to occur in the battery pack, such as the fixing bolts of the battery pack and the connection points of the battery pack shell. Since these positions are prone to tracer gas leakage, in the actual detection process, the preset positions correspond to the detection positions one by one.

[0072] In each displacement mode, the flow field model is used to simulate the flow state of the gas to obtain the concentration data of the tracer gas at each preset position. Then, the concentration data of each preset position is plotted into a curve in chronological order to obtain the reference concentration curve of each detection position.

[0073] For example, under displacement mode 1, the flow field model is used to simulate the flow state of the tracer gas entering the battery pack from the charging port, flowing inside the battery pack, and finally flowing out from the exhaust port, such as flow direction and flow rate. According to the simulation situation, the reference concentration curve of each detection position under displacement mode 1 is obtained. Similarly, the flow field model is used to simulate under other displacements in turn to obtain the reference concentration curve under each displacement mode.

[0074] It can be understood that for battery packs of different structures and different replacement methods, reference concentration curves can be simulated so that in actual detection, a suitable reference concentration curve can be selected according to actual conditions to determine whether there is a tracer gas leakage.

[0075] Based on the above embodiments, Figure 7 , the embodiment of the present application may also include:

[0076] Step 501 , under different replacement modes, a flow field model is used to simulate the flow state of gas in the structural model, and a first concentration uniformity of the tracer gas in the battery pack and a first replacement time required for the gas replacement to reach an equilibrium state are obtained.

[0077] Among them, concentration uniformity can characterize the average gas concentration in the battery pack. After the gas replacement reaches a balanced state, the change in gas concentration inside the battery pack is within a small range. In the non-equilibrium state before reaching a balanced state, the gas concentration inside the battery pack will gradually increase.

[0078] During the simulation process, the displacement mode can be subjected to a pull-off experiment, that is, under each displacement mode, the flow state of the tracer gas in the structural model is simulated by using a flow field model to obtain the flow state of the tracer gas inside the battery pack. The average gas concentration and / or the minimum gas concentration of the tracer gas in the battery pack can be determined based on the flow state, and the first concentration uniformity can be determined based on the average gas concentration and / or the minimum gas concentration. According to the flow state, the first displacement time from the start of inflation to the gas displacement reaching a balanced state can also be determined.

[0079] In an optional manner, a plurality of concentration intervals may be set, and after determining the average gas concentration of the tracer gas in the battery pack, the concentration interval in which the average gas concentration is located is determined to obtain a first concentration uniformity.

[0080] The data obtained by simulating with the flow field model can be shown in Table 1. Not marked in the table, the pressure at the inflation port is 3.5 kPa, and the pressure at the exhaust port is standard atmospheric pressure.

[0081] Table 1

[0082]

[0083] In Table 1, the specific gas replacement methods in the battery pack are as follows: Replacement method 1 includes 1 inlet and 1 exhaust port, the inlet and exhaust ports are arranged along the length direction (vertical axis) of the battery pack, and the pressure is standard atmospheric pressure; Replacement method 2 includes 1 inlet and 1 exhaust port, the inlet and exhaust ports are arranged along the width direction (horizontal axis) of the battery pack, and the pressure is standard atmospheric pressure; Replacement method 3 includes 1 inlet and 1 exhaust port, the inlet and exhaust ports are arranged along the diagonal direction of the battery pack, and the pressure is standard atmospheric pressure. The pressure is all standard atmospheric pressure; replacement method 4 is that the number of inflatable ports is 1 and the number of exhaust ports is 2, the inflatable ports and the exhaust ports are symmetrically distributed, and the pressure is all standard atmospheric pressure; replacement method 5 is that the number of inflatable ports is 1 and the number of exhaust ports is 4, the inflatable ports and the exhaust ports are symmetrically distributed, and the pressure is all standard atmospheric pressure; replacement method 6 is that the number of inflatable ports is 2 and the number of exhaust ports is 4, the inflatable ports and the exhaust ports are symmetrically distributed, and the pressure is all standard atmospheric pressure; replacement method 7 is that the number of inflatable ports is 2 and the number of exhaust ports is 4, the inflatable ports and the exhaust ports are symmetrically distributed, refer to Figure 6c , and the pressure at the inflation port is higher than the standard atmospheric pressure, and the pressure at the exhaust port is lower than the standard atmospheric pressure; replacement method 8 is that the number of inflation ports is 4, the number of exhaust ports is 2, the inflation ports and the exhaust ports are symmetrically distributed, and the pressures are both standard atmospheric pressure; replacement method 9 is that the number of inflation ports is 4, the number of exhaust ports is 2, the inflation ports and the exhaust ports are symmetrically distributed, and the pressure at the inflation port is higher than the standard atmospheric pressure, and the pressure at the exhaust port is lower than the standard atmospheric pressure.

[0084] It should be noted that the inflation port information, exhaust port information and replacement method include but are not limited to the above description, and can also be set according to actual conditions.

[0085] Step 502, determining an optimal replacement method from multiple replacement methods according to the first concentration uniformity and the first replacement time; wherein the optimal replacement method is used to optimize the detection structure.

[0086] Under different replacement modes, the simulated first concentration uniformity and first replacement time are different. By comparing the first concentration uniformity and first replacement time of multiple replacement modes, a replacement mode with good concentration uniformity and short replacement time can be selected, and the selected replacement mode is determined as the optimal replacement mode.

[0087] Referring to Table 1, the concentration uniformity corresponding to replacement method 9 is very good, and the replacement time is the shortest, that is, the gas replacement effect of replacement method 9 is good and the replacement efficiency is high. Therefore, replacement method 9 can be determined as the optimal replacement method in Table 1.

[0088] After determining the optimal replacement method, in the actual detection process, the replacement method 9 can be used to optimize the detection structure, that is, the detection structure adopts a 4-in 2-out structure. At the same time, in order to increase the air replacement speed of the battery pack, the inflation port uses positive pressure to accelerate inflation, and the exhaust port uses negative pressure to accelerate exhaust. It can be understood that the effect of gas replacement is good, which can improve the accuracy of air tightness detection; the high efficiency of gas replacement can improve the efficiency of air tightness detection.

[0089] In the above embodiment, under different replacement modes, the flow field model is used to simulate the flow state of the gas in the structural model, and the first concentration uniformity of the tracer gas in the battery pack and the first replacement time required for the gas replacement to reach an equilibrium state are obtained; according to the first concentration uniformity and the first replacement time, the optimal replacement mode is determined from multiple replacement modes. In the technical solution of the embodiment of the present application, the flow field model is used for simulation to find a better replacement mode, thereby effectively improving the gas replacement effect and the accuracy of the airtightness detection; and the gas replacement efficiency is effectively improved, and the efficiency of the airtightness detection is improved.

[0090] According to some embodiments of the present application, the simulation conditions include multiple air tube lengths. The length of the inflation tube and the length of the exhaust tube will affect the flow state of the gas. Therefore, different air tube lengths will have different effects and efficiencies of gas replacement. During the simulation process, multiple air tube lengths such as 1m, 100mm, and 6mm can be selected.

[0091] The above process of using the structural model, simulation conditions and flow field model to simulate the gas flow state and obtain the reference concentration curve of each detection position may include: under different airway lengths of the target replacement method, using the flow field model to simulate the flow state of the gas at each preset position on the structural model, and obtaining the reference concentration curve of each detection position under each airway length; wherein the preset position corresponds to the detection position one by one.

[0092] During the simulation, the trachea length deviation test can be performed for each replacement method, or the trachea length deviation test can be performed only for the target replacement method. It can be understood that the trachea length deviation can be performed only for the target replacement method to improve the simulation efficiency.

[0093] In an optional embodiment, the tracheal length is first fixed, and simulations are performed under various replacement modes to obtain simulation results corresponding to each replacement mode; then, the target replacement mode is determined based on the simulation results, and then under the target replacement mode, simulations are performed using different tracheal lengths to obtain reference concentration curves for each detection position under each tracheal length.

[0094] For example, the trachea length is first fixed to 6 mm, and then the simulation is performed in substitution modes 1-9 in turn to obtain the first concentration uniformity and the first substitution duration corresponding to each substitution mode. According to the first concentration uniformity and the first substitution duration, substitution mode 8 is determined as the target substitution mode. Then, under substitution mode 8, the trachea length is set to 6 mm, and the flow field model is used to simulate the flow state of the gas at each preset position on the structural model to obtain the reference concentration curve of each detection position when the trachea length is 6 mm. Afterwards, under substitution mode 8, the trachea length can be set to 100 mm and simulated, and the trachea length can be set to 1 m and simulated.

[0095] It can be understood that for various air pipe lengths, a reference concentration curve can be simulated so that in actual detection, a suitable reference concentration curve can be selected according to actual conditions to determine whether there is a tracer gas leak.

[0096] Based on the above embodiments, Figure 8 , the embodiment of the present application may also include:

[0097] Step 601, under different air pipe lengths of the target replacement mode, a flow field model is used to simulate the flow state of the gas in the structural model to obtain a second concentration uniformity of the tracer gas in the battery pack and a second replacement time required for the gas replacement to reach an equilibrium state.

[0098] Referring to the above simulation method, the air tube length is pulled off under the target replacement mode, that is, the flow field model is used to simulate the flow state of the tracer gas entering from the inflation port, flowing in the battery pack, and flowing out from the exhaust port, such as flow direction and flow rate, under various air tube lengths. The average gas concentration of the tracer gas in the battery pack can be determined based on the flow state, and the second concentration uniformity can be determined based on the average gas concentration. According to the flow state, the second replacement time from the start of inflation to the gas replacement reaching a balanced state can also be determined.

[0099] The data obtained by simulating with the flow field model can be shown in Table 2. Not marked in the table, the pressure at the inflation port is 3.5 kPa, and the pressure at the exhaust port is standard atmospheric pressure.

[0100] Table 2

[0101]

[0102]

[0103] Step 602, determining an optimal tracheal length from a plurality of tracheal lengths according to the second concentration uniformity and the second replacement time; the optimal tracheal length is used to optimize the detection structure.

[0104] Under different tracheal lengths, the simulated second concentration uniformity and second replacement time are different. By comparing the second concentration uniformity and second replacement time of multiple tracheal lengths, a tracheal length with good concentration uniformity and shortest replacement time can be selected, and the selected tracheal length is determined as the optimal tracheal length.

[0105] Referring to Table 2, the concentration uniformity corresponding to the tracheal length of 6 mm is very good, and the replacement time is the shortest, that is, the gas replacement effect of the tracheal length of 6 mm is good and the replacement efficiency is high. Therefore, the tracheal length of 6 mm can be determined as the optimal tracheal length in Table 2.

[0106] After determining the optimal replacement method, in the actual detection process, the replacement method 8 and the air tube length 6 can be used to optimize the detection structure, that is, the detection structure adopts a 4-in 2-out structure, and the air tube lengths of the inflation tube and the exhaust tube are both 6 mm. It can be understood that the good effect of gas replacement can improve the accuracy of air tightness detection; the high efficiency of gas replacement can improve the efficiency of air tightness detection.

[0107] In the above embodiment, under different air pipe lengths of the target replacement mode, the flow field model is used to simulate the flow state of the gas in the structural model to obtain the second concentration uniformity of the tracer gas in the battery pack and the second replacement time required for the gas replacement to reach an equilibrium state; according to the second concentration uniformity and the second replacement time, the optimal air pipe length is determined from multiple air pipe lengths. In the technical solution of the embodiment of the present application, the flow field model is used for simulation to find a more optimal air pipe length, thereby effectively improving the gas replacement efficiency and the efficiency of airtightness detection.

[0108] According to some embodiments of the present application, a method for detecting airtightness is provided. Figure 1 Taking the computer device in the example as an example, the following steps may be included:

[0109] Step 1, respectively obtaining the structural model and simulation conditions of the battery pack;

[0110] Step 2: Under different displacement modes, a flow field model is used to simulate the flow state of gas at each preset position in the structural model to obtain a reference concentration curve at each detection position under each displacement mode.

[0111] In the above simulation process, the first concentration uniformity of the tracer gas in the battery pack and the first replacement time required for the gas replacement to reach an equilibrium state can also be obtained; based on the first concentration uniformity and the first replacement time, the optimal replacement method is determined from multiple replacement methods.

[0112] Step 3, under different airway lengths of the target replacement mode, the flow field model is used to simulate the flow state of the gas at each preset position in the structural model to obtain the reference concentration curve of each detection position under each airway length.

[0113] In the above simulation process, the second concentration uniformity of the tracer gas in the battery pack and the second replacement time required for the gas replacement to reach an equilibrium state can also be obtained; based on the second concentration uniformity and the second replacement time, the optimal air pipe length is determined from multiple air pipe lengths.

[0114] Step 4: in the process of charging the battery pack with tracer gas, obtain the actual concentration curve of each detection position on the battery pack.

[0115] Step 5, for each detection position, respectively determine the first gas concentration corresponding to the preset detection time in the actual concentration curve and the second gas concentration corresponding to the preset detection time in the reference concentration curve;

[0116] Step 6: When the first gas concentration is greater than the second gas concentration, determine that the air tightness test result indicates that there is a tracer gas leak at the test location.

[0117] In the above embodiment, a reference concentration curve is obtained by pre-simulation. Since both the actual concentration curve and the reference concentration curve are data on the change in concentration of the tracer gas over time, they reflect the change in gas concentration at the detection position during the entire gas replacement process. Therefore, there is no need to wait for the tracer gas to completely replace the air in the battery pack and reach a balanced state before determining whether there is a tracer gas leakage. Therefore, the air-tightness detection time can be shortened, thereby improving the efficiency of the air-tightness detection.

[0118] It should be understood that, although the various steps in the above flowchart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the above flowchart may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0119] Based on the same inventive concept, the embodiment of the present application also provides an over-airtightness detection device for implementing the over-airtightness detection method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more over-airtightness detection device embodiments provided below can refer to the limitations of the over-airtightness detection method above, and will not be repeated here.

[0120] According to some embodiments of the present application, referring to Fig. 9 , provides an airtightness detection device, the device comprising:

[0121] The actual concentration acquisition module 701 is used to acquire the actual concentration curve of each detection position on the battery pack during the process of charging the tracer gas into the battery pack; the actual concentration curve includes the data of the concentration change of the tracer gas over time during the gas replacement process;

[0122] The airtightness detection module 702 is used to determine the airtightness detection result of each detection position based on the reference concentration curve and the actual concentration curve of each detection position; the reference concentration curve includes the data of the concentration change of the tracer gas over time obtained by pre-calculating using the flow field model, and the airtightness detection result is used to characterize whether there is a tracer gas leakage at the detection position.

[0123] In some embodiments, the airtightness detection module 702 is specifically used to determine, for each detection position, a first gas concentration corresponding to a preset detection time in an actual concentration curve and a second gas concentration corresponding to a preset detection time in a reference concentration curve; when the first gas concentration is greater than the second gas concentration, it is determined that the airtightness detection result indicates that there is a tracer gas leakage at the detection position.

[0124] In some embodiments, reference Fig.10 , the device further comprises:

[0125] The condition acquisition module 703 is used to respectively acquire the structural model and simulation conditions of the battery pack;

[0126] The simulation module 704 is used to simulate the gas flow state by using the structural model, simulation conditions and flow field model to obtain the reference concentration curve of each detection position.

[0127] In some embodiments, the simulation conditions include multiple replacement modes, and the replacement modes include inflation port information and exhaust port information; the simulation module 704 is specifically used to use a flow field model to simulate the flow state of gas at each preset position on the structural model under different replacement modes, and obtain a reference concentration curve for each detection position under each replacement mode; wherein the preset position corresponds one-to-one to the detection position.

[0128] In some embodiments, the simulation module 704 is also used to simulate the flow state of gas in the structural model under different replacement modes by using a flow field model, so as to obtain a first concentration uniformity of the tracer gas in the battery pack and a first replacement time required for the gas replacement to reach an equilibrium state; according to the first concentration uniformity and the first replacement time, an optimal replacement mode is determined from multiple replacement modes; and the optimal replacement mode is used to optimize the detection structure.

[0129] In some embodiments, the simulation conditions include multiple tracheal lengths; the simulation module 704 is specifically used to use a flow field model to simulate the flow state of gas at each preset position on the structural model under different tracheal lengths of the target replacement method, and obtain a reference concentration curve for each detection position under each tracheal length; wherein the preset position corresponds to the detection position one by one.

[0130] In some embodiments, the simulation module 704 is also used to simulate the flow state of gas in the structural model using a flow field model under different air tube lengths of the target replacement method, and obtain the second concentration uniformity of the tracer gas in the battery pack and the second replacement time required for the gas replacement to reach an equilibrium state; determine the optimal air tube length from multiple air tube lengths based on the second concentration uniformity and the second replacement time; the optimal air tube length is used to optimize the detection structure.

[0131] Each module in the above-mentioned airtightness detection device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in an electronic device in the form of hardware, or can be stored in a memory in the electronic device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0132] According to some embodiments of the present application, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Fig.11As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface, the display unit and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for detecting airtightness is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0133] Those skilled in the art will understand that Fig.11 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0134] According to some embodiments of the present application, there is also provided a non-transitory computer-readable storage medium including instructions, such as a memory including instructions, and the instructions can be executed by a processor of an electronic device to complete the above method. For example, the non-transitory computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0135] According to some embodiments of the present application, a computer program product is also provided, and when the computer program is executed by a processor, the above method can be implemented. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, part or all of the above method can be implemented in whole or in part according to the process or function described in the embodiment of the present application.

[0136] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0137] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solutions of the present application in detail, but cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the protection scope of the attached claims described in the present application. Therefore, the protection scope of the patent of this application shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. A method for detecting air tightness, characterized in that: The method comprises: In the process of charging the battery pack with tracer gas, obtaining an actual concentration curve at each detection position on the battery pack; the actual concentration curve includes data on the concentration change of the tracer gas over time during the gas replacement process; The airtightness test result of each detection position is determined according to the reference concentration curve and the actual concentration curve of each detection position; the reference concentration curve includes data of the concentration change of the tracer gas over time obtained by pre-calculating using a flow field model, and the airtightness test result is used to characterize whether there is a tracer gas leakage at the detection position.

2. The method according to claim 1, characterized in that Determining the airtightness detection result of each detection position according to the reference concentration curve and the actual concentration curve of each detection position includes: For each of the detection positions, respectively determining a first gas concentration corresponding to a preset detection time in the actual concentration curve and a second gas concentration corresponding to the preset detection time in the reference concentration curve; In a case where the first gas concentration is greater than the second gas concentration, determining that the airtightness detection result indicates that there is a tracer gas leakage at the detection position.

3. The method according to any one of claims 1 to 2, characterized in that: The method further comprises: Respectively obtaining a structural model and simulation conditions of the battery pack; The gas flow state is simulated using the structural model, the simulation conditions and the flow field model to obtain a reference concentration curve at each of the detection positions.

4. The method according to claim 3, characterized in that The simulation conditions include a plurality of replacement modes, and the replacement modes include information of the gas filling port and information of the gas exhaust port; the gas flow state is simulated by using the structural model, the simulation conditions and the flow field model to obtain a reference concentration curve at each detection position, including: Under different displacement modes, the flow field model is used to simulate the flow state of gas at each preset position on the structural model to obtain a reference concentration curve of each detection position under each displacement mode; wherein the preset position corresponds to the detection position one by one.

5. The method according to claim 4, characterized in that The method further comprises: Under different replacement modes, the flow field model is used to simulate the flow state of the gas in the structural model to obtain a first concentration uniformity of the tracer gas in the battery pack and a first replacement time required for the gas replacement to reach a balanced state; According to the first concentration uniformity and the first replacement time, an optimal replacement method is determined from the multiple replacement methods; the optimal replacement method is used to optimize the detection structure.

6. The method according to claim 4, characterized in that The simulation conditions include multiple airway lengths; the use of the structural model, the simulation conditions and the flow field model to simulate the gas flow state to obtain the reference concentration curve of each detection position includes: Under different tracheal lengths of the target replacement method, the flow field model is used to simulate the flow state of gas at each preset position on the structural model, and a reference concentration curve of each detection position under each tracheal length is obtained; wherein the preset position corresponds to the detection position one by one.

7. The method according to claim 6, characterized in that The method further comprises: Under different air pipe lengths of the target replacement mode, the flow field model is used to simulate the flow state of the gas in the structural model to obtain a second concentration uniformity of the tracer gas in the battery pack and a second replacement time required for the gas replacement to reach a balanced state; According to the second concentration uniformity and the second replacement time, an optimal tracheal length is determined from the multiple tracheal lengths; the optimal tracheal length is used to optimize the detection structure.

8. An airtightness detection device, characterized in that: The device comprises: An actual concentration acquisition module, used to acquire an actual concentration curve of each detection position on the battery pack during the process of charging the tracer gas into the battery pack; the actual concentration curve includes data on the concentration of the tracer gas changing with time during the gas replacement process; The airtightness detection module is used to determine the airtightness detection result of each detection position according to the reference concentration curve and the actual concentration curve of each detection position; the reference concentration curve includes the data of the concentration change of the tracer gas over time obtained by pre-simulating the flow field model, and the airtightness detection result is used to characterize whether there is a tracer gas leakage at the detection position.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

11. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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