Battery pack air tightness monitoring method and device and computer storage medium

Abstract

The invention provides a battery pack air tightness monitoring method, a battery pack air tightness monitoring device and a computer storage medium. The battery pack air tightness monitoring method is applied to a vehicle battery pack after leaving a factory. The battery pack air tightness monitoring method comprises the following steps: acquiring first air pressure data in the battery pack; acquiring second air pressure data outside the battery pack; acquiring air pressure change information based on the first air pressure data and the second air pressure data; based on the air pressure change information, determining the time delay duration inside and outside the battery pack; and determining the air tightness of the battery pack according to the time delay duration. According to the battery pack air tightness monitoring method, time hysteresis analysis ingeniously judges whether a new leakage point appears except the ventilation effect of the original explosion-proof valve, namely the air tightness of the battery pack fails, the air tightness of the battery pack can be continuously monitored after the battery pack leaves a factory, and the air tightness failure of the battery pack can be found in time to avoid greater safety risks.

Description

Technical Field

[0001] The present application relates to the technical field of air tightness detection, and in particular to a battery pack air tightness monitoring method, a battery pack air tightness monitoring device and a computer storage medium. Background Art

[0002] At present, the existing battery pack air tightness test is to test the battery pack before the electric vehicle leaves the factory. Since the explosion-proof valve on the battery pack has a ventilating function to achieve the function of balancing the air pressure, that is, the explosion-proof valve has a waterproof and breathable membrane with a micron-level aperture built in, the battery pack air tightness test usually adopts the method of sealing the explosion-proof valve first to prevent it from being ventilated, and then inflating the battery pack to test the air tightness. After the test is completed, the venting function of the explosion-proof valve is restored.

[0003] After electric vehicles are delivered to users, the battery pack may be damaged and lose its air tightness during long-term use due to foreign objects on the road, etc. At this time, unless obvious problems have occurred and the vehicle is returned to the factory, it is obviously impossible to detect the air tightness of the battery pack through an inflation test. In addition, due to the ventilation function of the explosion-proof valve, the conventional idea of ​​using an air pressure sensor to detect air tightness is also difficult to achieve. Summary of the invention

[0004] In order to solve the above technical problems, the present application proposes a battery pack air tightness monitoring method, a battery pack air tightness monitoring device and a computer storage medium.

[0005] In order to solve the above technical problems, the present application proposes a battery pack air tightness monitoring method, which is applied to a vehicle battery pack after leaving the factory. The battery pack air tightness monitoring method includes:

[0006] Acquiring first air pressure data inside the battery pack;

[0007] Acquiring second air pressure data outside the battery pack;

[0008] acquiring air pressure change information based on the first air pressure data and the second air pressure data;

[0009] Determining a time lag duration inside and outside the battery pack based on the air pressure change information;

[0010] The air tightness of the battery pack is determined according to the time lag duration.

[0011] The air pressure sensor for collecting the first air pressure data and the air pressure sensor for collecting the second air pressure data are respectively arranged on both sides of the explosion-proof valve of the battery pack.

[0012] Wherein, the battery pack air tightness monitoring method further includes:

[0013] Acquiring first temperature data inside the battery pack;

[0014] Acquiring second temperature data outside the battery pack;

[0015] Based on the first temperature data and the second temperature data, obtaining an internal and external temperature difference;

[0016] Obtaining a duration period during which the internal and external temperature difference is lower than a thermal balance threshold;

[0017] The battery pack air tightness monitoring program is started within the duration period.

[0018] The step of obtaining the duration of the period during which the internal and external temperature difference is lower than the thermal balance threshold comprises:

[0019] Obtain a duration during which the internal and external temperature difference is lower than a thermal balance threshold and the vehicle where the battery pack is located is in a stationary state.

[0020] Wherein, after the battery pack air tightness monitoring program is started within the duration period, the battery pack air tightness monitoring method further includes:

[0021] Based on the second air pressure data, obtaining an ambient air pressure change rate;

[0022] Determine whether the ambient air pressure change rate is higher than a preset change rate threshold and the duration exceeds a preset time threshold;

[0023] If so, continue the battery pack air tightness monitoring procedure.

[0024] Wherein, determining the air tightness of the battery pack according to the time lag duration includes:

[0025] Determine whether the time delay exceeds a preset time threshold;

[0026] If not, it is determined that the airtightness of the battery pack fails;

[0027] Obtaining a difference between the time lag duration and the preset duration threshold;

[0028] The aperture diameter of the battery pack is determined based on the difference.

[0029] Wherein, determining the air tightness of the battery pack according to the time lag duration includes:

[0030] Determine whether the time delay exceeds a preset time threshold;

[0031] If not, it is determined that the airtightness of the battery pack fails;

[0032] Obtaining failure time thresholds corresponding to opening apertures of different sizes of the battery pack;

[0033] Obtaining the difference between the time lag duration and the failure duration thresholds of different sizes;

[0034] The aperture of the battery pack is determined according to the failure time threshold corresponding to the minimum difference.

[0035] Wherein, determining the time lag duration inside and outside the battery pack based on the air pressure change information includes:

[0036] Based on the air pressure change information, determining a time difference between the same air pressure values ​​in the first air pressure data and the second air pressure data;

[0037] The time difference is used to determine the time lag duration inside and outside the battery pack.

[0038] In order to solve the above-mentioned technical problems, the present application also proposes a battery pack air tightness monitoring device, which includes a memory and a processor coupled to the memory; wherein the memory is used to store program data, and the processor is used to execute the program data to implement the battery pack air tightness monitoring method as described above.

[0039] In order to solve the above technical problems, the present application also proposes a computer storage medium, which is used to store program data. When the program data is executed by a computer, it is used to implement the above-mentioned battery pack air tightness monitoring method.

[0040] Compared with the prior art, the beneficial effects of the present application are: the battery pack air tightness monitoring method is applied to a vehicle battery pack after leaving the factory, and the battery pack air tightness monitoring method includes: obtaining first air pressure data inside the battery pack; obtaining second air pressure data outside the battery pack; obtaining air pressure change information based on the first air pressure data and the second air pressure data; determining the time lag duration inside and outside the battery pack based on the air pressure change information; and determining the air tightness of the battery pack according to the time lag duration. Through the above-mentioned battery pack air tightness monitoring method, the time lag analysis cleverly determines whether there is a new leak point in addition to the ventilation effect of the original explosion-proof valve, that is, the battery pack air tightness fails, and can continue to monitor the air tightness of the battery pack after leaving the factory, and promptly detect the failure of the battery pack air tightness to avoid greater safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] in:

[0043] Figure 1 It is a flow chart of the first embodiment of the battery pack air tightness monitoring method provided by the present application;

[0044] Figure 2 This is a flow chart of a user operating a simulated device through a real device proxy provided by this application;

[0045] Figure 3 This is a comparison chart of the air flow rate of the explosion-proof valve provided in the present application, and the explosion-proof valve and 1mm hole being air-permeable at the same time;

[0046] Figure 4 It is a schematic diagram of an embodiment of an ambient air pressure change curve provided by the present application;

[0047] Figure 5 It is a schematic diagram of the change curve of the air pressure inside the battery pack and the ambient air pressure under the condition that only the explosion-proof valve is ventilated provided by the present application;

[0048] Figure 6 Zhongwei Figure 5 A partial enlarged view of the air pressure variation curve shown;

[0049] Figure 7 It is a schematic diagram of the change curve of the air pressure inside the battery pack and the ambient air pressure under the condition that the explosion-proof valve and the 1mm hole are both ventilated provided by the present application;

[0050] Figure 8 Zhongwei Figure 7 A partial enlarged view of the air pressure variation curve shown;

[0051] Fig. 9 It is a flow chart of the second embodiment of the battery pack air tightness monitoring method provided by the present application;

[0052] Fig.10 It is a flow chart of the third embodiment of the battery pack air tightness monitoring method provided by the present application;

[0053] Fig.11 is a flow chart of a fourth embodiment of a battery pack air tightness monitoring method provided by the present application;

[0054] Fig.12 is a flow chart of a fifth embodiment of a battery pack air tightness monitoring method provided by the present application;

[0055] Fig.13 It is a structural schematic diagram of an embodiment of a battery pack air tightness monitoring device provided by the present application;

[0056] Fig.14 It is a structural diagram of an embodiment of a computer storage medium provided by the present application. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0059] The air tightness of the battery pack is important for the battery, and good air tightness can reduce the risk of short circuit and corrosion of the battery and other auxiliary structures. The technical problem to be solved by this application is how to achieve long-term monitoring of the air tightness of the battery pack after the electric vehicle is delivered to the user.

[0060] This application cleverly proposes a battery pack air tightness monitoring method: by arranging an air pressure sensor inside and outside the battery pack, the correlation of the air pressure change data collected simultaneously by the two air pressure sensors is used to determine whether the battery pack has airtightness failure.

[0061] Furthermore, two air pressure sensors may be integrated on the explosion-proof valve of the battery pack, the air pressure sensor on the inside of the explosion-proof valve is used to monitor the air pressure inside the battery pack, and the air pressure sensor on the outside of the explosion-proof valve is used to monitor the air pressure outside the battery pack.

[0062] The existing battery pack air tightness detection scheme is mainly used for battery pack air tightness testing before leaving the factory, and it is difficult to monitor the air tightness of the battery pack after the electric vehicle is delivered to the user. This application can timely detect air tightness failure caused by battery pack damage during the user's use of the vehicle, avoiding greater safety risks.

[0063] Please refer to Figure 1 and Figure 2 , Figure 1 is a flow chart of the first embodiment of the battery pack air tightness monitoring method provided by the present application, Figure 2 This is a flow chart of a user operating a simulated device through a real device agent provided by this application.

[0064] The battery pack air tightness monitoring method of the present application is applied to the battery pack air tightness monitoring device, wherein the battery pack air tightness monitoring device of the present application can be a server, a terminal device, or a system composed of a server and a terminal device. Accordingly, the various parts of the battery pack air tightness monitoring device, such as various units, sub-units, modules, and sub-modules, can all be set in the server, can all be set in the terminal device, or can be set in the server and the terminal device respectively.

[0065] Furthermore, the above-mentioned server can be hardware or software. When the server is hardware, it can be implemented as a distributed server cluster consisting of multiple servers, or it can be implemented as a single server. When the server is software, it can be implemented as multiple software or software modules, such as software or software modules used to provide distributed servers, or it can be implemented as a single software or software module, which is not specifically limited here.

[0066] like Figure 1 As shown, the specific steps are as follows:

[0067] Step S11: Acquire first air pressure data inside the battery pack.

[0068] Step S12: Acquire the second air pressure data outside the battery pack.

[0069] In the embodiment of the present application, the battery pack explosion-proof valve has a ventilation effect, but because the internal air permeable membrane is a porous medium with a single hole diameter of micrometer level, the battery pack air pressure balance function achieved by the explosion-proof valve will show a certain time lag. That is, when the external environmental air pressure changes, the air pressure in the battery pack will also change with a certain time lag.

[0070] When the battery pack loses its airtightness due to structural damage caused by foreign objects on the road or other reasons, for example, new pores may appear in the battery pack, and the pore size may be in the millimeter level. If the external ambient air pressure changes, not only the explosion-proof valve will be ventilated, but the new pores will also allow gas exchange within the battery pack. Therefore, the air pressure within the battery pack will better follow the external ambient air pressure, that is, the time lag will be reduced.

[0071] Therefore, the main idea of ​​this application is to detect the changes in air pressure inside and outside the battery pack, so as to determine the time lag inside and outside the battery pack.

[0072] Specifically, the battery pack air tightness monitoring device collects first air pressure data inside the battery pack and second air pressure data outside the battery pack through air pressure sensors arranged on both sides of the battery pack explosion-proof valve.

[0073] Please refer to Figure 3 , Figure 3 This is a comparison chart of the air flow rate of the explosion-proof valve and the explosion-proof valve and 1mm hole in two cases. This application provides an electric vehicle battery pack with a free volume of 200L and an explosion-proof valve. The experimental test results of the air permeability curve of the explosion-proof valve air permeability function can be found in Figure 3 If the battery pack fails to be airtight and a new pore with a diameter of 1 mm appears, the air permeability curve corresponding to the pore with a diameter of 1 mm is calculated based on the Bernoulli equation as follows: Figure 3 shown.

[0074] Step S13: Acquire air pressure change information based on the first air pressure data and the second air pressure data.

[0075] In an embodiment of the present application, the battery pack air tightness monitoring device transforms the first air pressure data and the second air pressure data inside and outside the battery pack into the same coordinate system to facilitate analysis of the time lag inside and outside the battery pack in the current state.

[0076] Step S14: Determine the time lag duration inside and outside the battery pack based on the air pressure change information.

[0077] In the embodiment of the present application, the battery pack air tightness monitoring device analyzes the time difference between the two air pressure curves at the same air pressure value in the same coordinate system. For example, the battery pack air tightness monitoring device obtains the first time of the fixed air pressure value in the first air pressure data, the second time of the fixed air pressure value in the second air pressure data, and obtains the time difference between the first time and the second time.

[0078] The battery pack air tightness monitoring device uses the time difference as the time lag inside and outside the battery pack.

[0079] Furthermore, the battery pack air tightness monitoring device can analyze the time difference of several fixed air pressure values, and use the maximum value, minimum value, average value or mode of the several time differences as the time lag duration inside and outside the battery pack.

[0080] Step S15: Determine the air tightness of the battery pack according to the time lag duration.

[0081] In the embodiment of the present application, the battery pack air tightness monitoring device determines the air tightness state of the battery pack according to the time lag duration calculated in step S14. For example, the battery pack air tightness monitoring device obtains the time lag threshold when the air tightness of the battery pack has not failed. When the time lag duration of the battery pack of the vehicle after leaving the factory is less than the time lag threshold, the battery pack air tightness monitoring device determines that the air tightness of the battery pack has failed; when the time lag duration of the battery pack of the vehicle after leaving the factory is greater than or equal to the time lag threshold, the battery pack air tightness monitoring device determines that the air tightness of the battery pack has not failed.

[0082] For example, considering the error, Figure 2 As shown, the battery pack airtightness monitoring device can also regard the battery pack airtightness as failed if the hysteresis time obtained under the monitoring conditions is less than half of the original hysteresis time.

[0083] Furthermore, if Figure 2 As shown, the original lag time of the battery pack, that is, the time lag threshold, is mainly determined by calibrating the characteristic parameters of the battery pack air pressure lag time before leaving the factory, and is saved in a storage medium or uploaded to cloud storage.

[0084] Regarding the calibration of the characteristic parameters of the battery pack air pressure hysteresis time, the simulation calculation is mainly carried out to show the changes in the air pressure in the battery pack after the external environmental air pressure changes in two cases: only the explosion-proof valve is ventilated and the explosion-proof valve and the 1mm hole are ventilated at the same time.

[0085] In a specific embodiment, the atmospheric pressure of the environment will naturally fluctuate within 24 hours a day. Usually, the difference between the maximum and minimum atmospheric pressure is within 0.5 kPa. When simulating, a typical scenario in which the ambient atmospheric pressure drops by 0.2 kPa within two hours is used as an example. Figure 4 As shown, Figure 4 It is a schematic diagram of an embodiment of an ambient air pressure variation curve provided by the present application.

[0086] The change curve of the air pressure inside the battery pack and the ambient air pressure under the condition of only the explosion-proof valve being ventilated is calculated as follows: Figure 5 and Figure 6 As shown, Figure 6 Zhongwei Figure 5 The partial enlarged view of the air pressure change curve shown, this time period corresponds to Figure 4 The corresponding ambient pressure change rate is >1.2Pa / min. Figure 6 The enlarged view shows that the lag time is about 150s.

[0087] The calculated curve of the change of the air pressure inside the battery pack and the ambient air pressure under the condition of both the explosion-proof valve and the 1mm hole being ventilated is as follows: Figure 7 and Figure 8 As shown, Figure 8 Zhongwei Figure 7 The partial enlarged view of the air pressure change curve shows a lag time of about 60s. This shows that when the air tightness of the battery pack fails, the lag time of the air pressure inside the battery pack following the change of the ambient air pressure will indeed change significantly, and the lag time will be shortened. Therefore, this can be used as a basis to judge whether the air tightness of the battery pack has failed, that is, to achieve air tightness monitoring of the battery pack.

[0088] It should be noted that if the aperture of the opening is more than 1 mm, the hysteresis time will become shorter. The hysteresis time can be calibrated through preliminary experiments or simulations, and in actual applications, it can be regarded as a characteristic parameter for logical judgment.

[0089] In the present application, the battery pack air tightness monitoring device obtains the first air pressure data inside the battery pack; obtains the second air pressure data outside the battery pack; obtains the air pressure change information based on the first air pressure data and the second air pressure data; determines the time lag duration inside and outside the battery pack based on the air pressure change information; and determines the air tightness of the battery pack according to the time lag duration. Through the above-mentioned battery pack air tightness monitoring method, the time lag analysis cleverly determines whether there is a new leak point in addition to the ventilation effect of the original explosion-proof valve, that is, the battery pack air tightness fails. It can continue to monitor the air tightness of the battery pack after it leaves the factory, and promptly detect the failure of the battery pack air tightness to avoid greater safety risks.

[0090] Please continue to combine Figure 2 See also Fig. 9 , Fig. 9 It is a flow chart of the second embodiment of the battery pack air tightness monitoring method provided in the present application.

[0091] like Fig. 9 As shown, the specific steps are as follows:

[0092] Step S21: Acquire first temperature data inside the battery pack.

[0093] Step S22: Acquire second temperature data outside the battery pack.

[0094] Before performing battery pack air tightness monitoring, the battery pack air tightness monitoring device needs to first determine that the state of the battery pack meets the air tightness monitoring conditions, that is, the battery pack is in a static state and thermal equilibrium state.

[0095] Therefore, the battery pack air tightness monitoring device needs to collect temperature data inside and outside the battery pack, that is, to obtain first temperature data and second temperature data.

[0096] Step S23: Based on the first temperature data and the second temperature data, obtain the internal and external temperature difference.

[0097] In the embodiment of the present application, the battery pack air tightness monitoring device determines whether the inside and outside of the battery pack are in a thermal equilibrium state based on the first temperature data and the second temperature data.

[0098] Step S24: Obtain the duration of the period during which the internal and external temperature difference is lower than the thermal balance threshold.

[0099] In the embodiment of the present application, the battery pack air tightness monitoring device determines the state in which the temperature difference between the inside and outside of the battery pack is lower than the thermal equilibrium threshold as a thermal equilibrium state, and further obtains the duration of the thermal equilibrium state.

[0100] Furthermore, when obtaining the duration period, in addition to satisfying the thermal equilibrium state condition, it is also necessary to ensure that the electric vehicle in which the battery pack is located is in a stationary state to ensure the accuracy of the battery pack air tightness monitoring.

[0101] Step S25: Start the battery pack air tightness monitoring program within the duration period.

[0102] In the embodiment of the present application, the battery pack air tightness monitoring device performs the following operations within a duration period that meets the air tightness monitoring conditions: Figure 1 The battery pack air tightness monitoring procedure shown.

[0103] The specific method is illustrated as follows. In addition, it should be noted that when the battery pack airtightness monitoring method of the present application is applied to electric vehicles, in order to avoid interference from factors such as vehicle movement and battery pack heating, it is selected after the electric vehicle is parked and the battery pack and the environment achieve thermal equilibrium, that is, the temperature is equalized. For example, the vehicle is parked overnight in a parking space. At this time, the judgment of vehicle stopping can come from the on-board signal, and the judgment of thermal equilibrium can be based on the temperature difference of the temperature sensors inside and outside the battery pack being less than 1°C, and then the air pressure changes in the natural environment are used to perform airtightness judgment.

[0104] Please continue to combine Figure 2 See also Fig.10 , Fig.10 It is a flow chart of the third embodiment of the battery pack air tightness monitoring method provided in the present application.

[0105] like Fig.10 As shown, the specific steps are as follows:

[0106] Step S31: based on the second air pressure data, obtaining the ambient air pressure change rate.

[0107] Step S32: Determine whether the ambient air pressure change rate is higher than a preset change rate threshold and the duration exceeds a preset time threshold.

[0108] Step S33: Continue the battery pack air tightness monitoring procedure.

[0109] In the embodiments of the present application, Figure 2 As shown, before calculating the time lag duration of the battery pack, the battery pack air tightness monitoring device needs to monitor whether the current ambient air pressure change rate is higher than the preset change rate threshold and the duration exceeds the preset time threshold, so as to determine whether the change in ambient air pressure is sufficient to obviously reflect the time lag duration of the air pressure change inside and outside the battery pack, and to quantify the air tightness with a clear numerical value.

[0110] Furthermore, in addition to being able to determine the airtightness status of the battery pack, the battery pack airtightness monitoring method of the present application can also predict the aperture of the opening of the battery pack when the airtightness fails.

[0111] Please continue to read Fig.11 , Fig.11 It is a flow chart of the fourth embodiment of the battery pack air tightness monitoring method provided in the present application.

[0112] like Fig.11 As shown, the specific steps are as follows:

[0113] Step S41: Determine whether the time delay duration exceeds a preset duration threshold.

[0114] Step S42: Determine that the airtightness of the battery pack fails.

[0115] In the embodiments of the present application, Figure 1 As shown in the embodiment of the invention, the battery pack airtightness monitoring device determines that the battery pack has failed to be airtight when the time lag of the battery pack does not exceed the preset time threshold. Furthermore, the battery pack airtightness monitoring device continues to predict the aperture of the opening of the battery pack.

[0116] Step S43: Obtain the difference between the time delay duration and a preset duration threshold.

[0117] Step S44: determining the aperture of the battery pack based on the difference.

[0118] In the embodiment of the present application, the battery pack air tightness monitoring device mainly predicts the aperture of the battery pack through the difference between the time lag duration and the preset time threshold. Figures 5 to 8For example, the preset time threshold of the battery pack is 150s, and the time lag of the 1mm opening aperture is 60s, so the difference corresponding to the 1mm opening aperture is 90s. If the difference between the current time lag and the preset time threshold is close to 90s, it can be predicted that the opening aperture of the battery pack is 1mm. Therefore, the battery pack airtightness monitoring device can determine and store the difference corresponding to the opening apertures of various sizes through simulation.

[0119] Please continue to read Fig.12 , Fig.12 It is a flow chart of the fifth embodiment of the battery pack air tightness monitoring method provided in the present application.

[0120] like Fig.12 As shown, the specific steps are as follows:

[0121] Step S51: Determine whether the time delay duration exceeds a preset duration threshold.

[0122] Step S52: Determine whether the airtightness of the battery pack fails.

[0123] In the embodiments of the present application, Figure 1 As shown in the embodiment of the invention, the battery pack airtightness monitoring device determines that the battery pack has failed to be airtight when the time lag of the battery pack does not exceed the preset time threshold. Furthermore, the battery pack airtightness monitoring device continues to predict the aperture of the opening of the battery pack.

[0124] Step S53: Obtain failure time thresholds corresponding to opening apertures of different sizes in the battery pack.

[0125] Step S54: Obtain the difference between the time lag duration and the failure duration thresholds of different sizes.

[0126] Step S55: Determine the aperture of the battery pack according to the failure duration threshold corresponding to the minimum difference.

[0127] In the embodiment of the present application, the battery pack air tightness monitoring device mainly predicts the aperture of the battery pack through the difference between the time lag duration and the preset time threshold. Figures 5 to 8For example, the preset time threshold of the battery pack is 150s, and the time lag time of the opening aperture of 1mm is 60s, so the failure time threshold corresponding to the opening aperture of 1mm is 60s. For another example, the failure time threshold corresponding to the opening aperture of 2mm is 20s. If the current time lag time is 50s, the difference between the current time lag time and the failure time threshold corresponding to the opening aperture of 1mm is 10s, and the difference between the current time lag time and the failure time threshold corresponding to the opening aperture of 2mm is 30s, then it can be predicted that the opening aperture of the battery pack is 1mm. Therefore, the battery pack airtightness monitoring device can determine and store the failure time thresholds corresponding to the opening apertures of various sizes through simulation.

[0128] Furthermore, the battery pack airtightness monitoring device can also predict the opening area on the battery pack according to the time lag duration of the current battery pack when determining that the battery pack's airtightness has failed. Its prediction logic is basically the same as the above-mentioned logic for predicting the opening aperture, and will not be repeated here.

[0129] It should be noted that the above-mentioned opening area is the total area of ​​at least one opening, that is, there is no need to predict the aperture or area of ​​each opening, only the total area needs to be predicted.

[0130] Furthermore, for the failure time threshold used in the above prediction scheme, the battery pack airtightness monitoring device may have multiple consecutive thresholds, corresponding to multiple consecutive aperture simulation values ​​or area simulation values. During the prediction process, the battery pack airtightness monitoring device only needs to compare multiple consecutive aperture simulation values ​​or area simulation values ​​one by one to complete the prediction scheme.

[0131] The battery pack air tightness monitoring method of the present application can continue to monitor the air tightness of the battery pack after it leaves the factory, and promptly detect the failure of the battery pack air tightness to avoid greater safety risks.

[0132] The battery pack air tightness monitoring method of the present application is low-cost and easy to implement. In terms of hardware, only two air pressure sensors are needed, and in terms of software, only calibration and judgment logic need to be done according to actual conditions.

[0133] The battery pack air tightness monitoring method of the present application has good adaptability and is not limited to electric vehicles. The battery packs used in other scenarios such as energy storage can also be used to monitor the air tightness of the battery packs.

[0134] Those skilled in the art will appreciate that, in the above method of specific implementation, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of the steps should be determined by their functions and possible internal logic.

[0135] In order to implement the above-mentioned battery pack air tightness monitoring method, the present application also proposes a battery pack air tightness monitoring device, please refer to Fig.13 , Fig.13 It is a structural schematic diagram of an embodiment of a battery pack air tightness monitoring device provided in the present application.

[0136] The battery pack airtightness monitoring device 700 of this embodiment includes a processor 71 , a memory 72 , an input / output device 73 , and a bus 74 .

[0137] The processor 71 , the memory 72 , and the input / output device 73 are respectively connected to the bus 74 . The memory 72 stores program data, and the processor 71 is used to execute the program data to implement the battery pack air tightness monitoring method described in the above embodiment.

[0138] In the embodiment of the present application, the processor 71 may also be referred to as a CPU (Central Processing Unit). The processor 71 may be an integrated circuit chip having the ability to process signals. The processor 71 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, or discrete hardware components. A general-purpose processor may be a microprocessor or the processor 71 may also be any conventional processor, etc.

[0139] This application also provides a computer storage medium, please continue to refer to Fig.14 , Fig.14 It is a structural diagram of an embodiment of a computer storage medium provided in the present application. The computer storage medium 600 stores a computer program 61. When the computer program 61 is executed by the processor, it is used to implement the battery pack air tightness monitoring method of the above embodiment.

[0140] When the embodiments of the present application are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk.

[0141] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for monitoring the air tightness of a battery pack, characterized in that: The battery pack air tightness monitoring method is applied to a vehicle battery pack after leaving the factory, and the battery pack air tightness monitoring method includes: Acquiring first air pressure data inside the battery pack; Acquiring second air pressure data outside the battery pack; acquiring air pressure change information based on the first air pressure data and the second air pressure data; Determining a time lag duration inside and outside the battery pack based on the air pressure change information; The air tightness of the battery pack is determined according to the time lag duration.

2. The battery pack air tightness monitoring method according to claim 1, characterized in that: The air pressure sensor for collecting the first air pressure data and the air pressure sensor for collecting the second air pressure data are respectively arranged on both sides of the explosion-proof valve of the battery pack.

3. The battery pack air tightness monitoring method according to claim 1, characterized in that: The battery pack air tightness monitoring method further includes: Acquiring first temperature data inside the battery pack; Acquiring second temperature data outside the battery pack; Based on the first temperature data and the second temperature data, obtaining an internal and external temperature difference; Obtaining a duration period during which the internal and external temperature difference is lower than a thermal balance threshold; The battery pack air tightness monitoring program is started within the duration period.

4. The method for monitoring the air tightness of a battery pack according to claim 3, characterized in that: The step of obtaining the duration of the period during which the internal and external temperature difference is lower than the thermal balance threshold comprises: Obtain a duration during which the internal and external temperature difference is lower than a thermal balance threshold and the vehicle where the battery pack is located is in a stationary state.

5. The method for monitoring the air tightness of a battery pack according to claim 3, characterized in that: After the battery pack air tightness monitoring program is started within the duration period, the battery pack air tightness monitoring method further includes: Based on the second air pressure data, obtaining an ambient air pressure change rate; Determine whether the ambient air pressure change rate is higher than a preset change rate threshold and the duration exceeds a preset time threshold; If so, continue the battery pack air tightness monitoring procedure.

6. The method for monitoring the air tightness of a battery pack according to claim 1, characterized in that: The step of determining the air tightness of the battery pack according to the time lag duration includes: Determine whether the time delay exceeds a preset time threshold; If not, it is determined that the airtightness of the battery pack fails; Obtaining a difference between the time lag duration and the preset duration threshold; The aperture diameter of the battery pack is determined based on the difference.

7. The method for monitoring the air tightness of a battery pack according to claim 1, characterized in that: The step of determining the air tightness of the battery pack according to the time lag duration includes: Determine whether the time delay exceeds a preset time threshold; If not, it is determined that the airtightness of the battery pack fails; Obtaining failure time thresholds corresponding to opening apertures of different sizes of the battery pack; Obtaining the difference between the time lag duration and the failure duration thresholds of different sizes; The aperture of the battery pack is determined according to the failure time threshold corresponding to the minimum difference.

8. The method for monitoring the air tightness of a battery pack according to claim 1, characterized in that: The determining, based on the air pressure change information, the time lag duration inside and outside the battery pack includes: Based on the air pressure change information, determining a time difference between the same air pressure values ​​in the first air pressure data and the second air pressure data; The time difference is used to determine the time lag duration inside and outside the battery pack.

9. A battery pack air tightness monitoring device, characterized in that: The battery pack air tightness monitoring device includes a memory and a processor coupled to the memory; Wherein, the memory is used to store program data, and the processor is used to execute the program data to implement the battery pack air tightness monitoring method as described in any one of claims 1 to 8.

10. A computer storage medium, characterized in that: The computer storage medium is used to store program data, and when the program data is executed by a computer, it is used to implement the battery pack air tightness monitoring method as described in any one of claims 1 to 8.

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