Vehicle battery pack airtightness detection method and device, vehicle and electronic equipment

Abstract

The invention relates to an air tightness detection method and device of a vehicle battery pack, a vehicle and electronic equipment, relates to the technical field of batteries, and aims to realize real-time detection of the air tightness of the vehicle battery pack. The method comprises the following steps: determining a parameter change rate of at least one environmental parameter based on at least one environmental parameter in the vehicle battery pack; the environmental parameters are air pressure, humidity, temperature or gas concentration. And under the condition that the parameter change rate of the at least one environmental parameter is greater than the preset parameter change rate, the air tightness of the battery pack is detected based on the respective time sequence parameter data of the at least one environmental parameter and the air tightness detection model, so that the air tightness of the whole life cycle of the vehicle battery pack can be detected in real time, and the safety of the battery pack is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a method, apparatus, vehicle, and electronic equipment for testing the airtightness of a vehicle battery pack. Background Technology

[0002] With the large-scale application of lithium batteries in key areas such as electric vehicles and energy storage systems, the safety performance of power battery packs, as core energy storage units, has become a key factor restricting the development of related industries. Among these factors, the internal airtightness of the battery pack is a crucial barrier to effectively isolate the battery pack from harsh external environments (such as humidity, dust, and corrosive gases), directly determining the battery pack's waterproof and dustproof rating and its long-term safe operational stability. Insufficient airtightness or failure to maintain airtightness can lead to the intrusion of moisture and dust into the battery, causing a series of serious safety accidents such as internal short circuits, cell bulging, localized overheating, and even thermal runaway.

[0003] Currently, the mainstream battery pack airtightness testing methods in the industry mostly adopt the offline testing mode, that is, a one-time inspection is carried out after production using the static pressure decay method or differential pressure method. Although this type of method ensures that the airtightness of the products leaving the factory meets the standards to a certain extent, it has significant technical limitations.

[0004] One related technology discloses an optimization of the airtightness testing process for battery packs, improving the efficiency and accuracy of airtightness testing and solving problems such as low efficiency and poor consistency of test results in traditional manual testing methods. However, this solution is essentially still a static testing method at the battery pack production line stage, which can only achieve a one-time airtightness qualification verification at the factory and cannot dynamically monitor the real-time air pressure status of the battery pack under complex operating conditions after it is packed into the vehicle.

[0005] Another related technology discloses a method for testing the airtightness of a battery pack by inflating it to a pressure greater than atmospheric pressure, acquiring the internal gas pressure after inflation, and determining the airtightness of the battery pack based on the change in gas pressure. This allows for the detection of battery pack airtightness throughout the vehicle's service life. However, this approach relies on active inflation and pressure sampling, and cannot achieve continuous, real-time monitoring of the battery pack's airtightness throughout its entire lifespan. Furthermore, this approach can only identify and trigger alarms after an airtightness failure occurs, lacking proactive protection against potential intrusion risks. Summary of the Invention

[0006] This application provides a method, apparatus, vehicle, and electronic equipment for testing the airtightness of a vehicle battery pack, which can perform real-time testing of the airtightness of the vehicle battery pack throughout its entire life cycle, thereby improving the safety of the battery pack.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows: According to a first aspect of this application, a method for testing the airtightness of a vehicle battery pack is provided. The method includes: determining the rate of change of at least one environmental parameter based on at least one environmental parameter inside the vehicle battery pack; the environmental parameter being air pressure, humidity, temperature, or gas concentration. If the rate of change of at least one environmental parameter is greater than a preset rate of change, the battery pack is tested for airtightness based on time-series parameter data of each of the at least one environmental parameter and an airtightness testing model.

[0008] Based on the aforementioned technical means, this application can monitor the rate of change of different environmental parameters inside the vehicle battery pack in real time, and quantify the intensity of parameter fluctuations through the rate of change of each environmental parameter, providing clear triggering conditions for subsequent testing and avoiding missed or false detections. Furthermore, when the rate of change of any environmental parameter exceeds its corresponding preset parameter rate of change, it is determined that the battery pack has a "potential airtightness anomaly," triggering subsequent precise airtightness testing. This involves calling an airtightness testing model to perform battery pack airtightness testing. By providing the model with time-series parameter data from multiple environmental dimensions, the dynamic process of airtightness changes within the battery pack can be fully covered, thereby improving the accuracy of battery airtightness testing.

[0009] Among them, the core manifestation of battery pack airtightness failure is the imbalance of air pressure inside and outside the battery pack (such as a drop in internal air pressure due to leakage). Air pressure parameters can directly reflect the degree of leakage. When external moisture enters through the leak point, the humidity inside the battery pack will increase significantly. By monitoring the humidity inside the battery pack in real time, it is possible to avoid missing "slow leakage" scenarios due to a single air pressure detection, reduce the risk of battery short circuits and corrosion caused by moisture intrusion, and enhance safety. Temperature changes will affect the baseline values ​​of air pressure and humidity. By monitoring the temperature inside the battery pack in real time, parameter fluctuations caused by non-leakage factors (such as air pressure changes caused by battery heating) can be eliminated, reducing the false detection rate. For characteristic gases inside the battery pack (such as hydrogen generated by electrolyte evaporation), the concentration change directly reflects the degree of sealing failure.

[0010] In one possible approach, based on at least one environmental parameter within the vehicle battery pack, the rate of change of each of the at least one environmental parameter is determined, including: correcting the air pressure based on the altitude of the battery pack and the external ambient temperature; and using the corrected air pressure to determine the rate of change of air pressure.

[0011] Based on the aforementioned technical methods, the changes in altitude and temperature of the battery pack significantly affect the internal air pressure, directly impacting the accuracy of airtightness testing and the reliability of the abnormal gas monitoring system. Therefore, this application utilizes the battery pack's altitude and ambient temperature to eliminate pressure benchmark differences caused by altitude and temperature, restoring the original air pressure state of the battery pack's seal and ensuring the accuracy of the pressure change rate.

[0012] In one possible approach, the air pressure is corrected based on the altitude of the battery pack and the ambient temperature, including: determining the temperature difference between the ambient temperature and a reference temperature; determining a first compensation coefficient by multiplying the temperature difference by a temperature compensation coefficient; determining the altitude difference between the altitude and a reference altitude; determining a second compensation coefficient by multiplying the altitude difference by an altitude compensation coefficient; and determining the corrected air pressure based on the first compensation coefficient, the second compensation coefficient, and the air pressure.

[0013] In one possible approach, the airtightness testing method for a vehicle battery pack further includes: in the event of an airtightness anomaly in the battery pack, determining the water wading risk level of the battery pack based on time-series parameter data of at least one environmental parameter and a water wading risk prediction model; and implementing water wading protection control for the battery pack based on the water wading risk level.

[0014] Based on the aforementioned technical methods, the time-series data of various environmental parameters (such as the trend of decreasing air pressure, the rate of increase in humidity, and the gas concentration change curve) can reflect the severity of airtightness anomalies (such as rapid leakage vs. slow leakage), providing a precise basis for the water immersion risk level of the battery pack. Furthermore, by predicting the water immersion risk of the battery pack in advance using a water immersion risk prediction model, serious failures such as battery short circuits and corrosion caused by water intrusion can be avoided in advance. In addition, matching corresponding water immersion protection measures as needed based on different water immersion risk levels can improve the effectiveness of water immersion protection.

[0015] In one possible approach, the gas concentrations include hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration. Based on this, the water hazard level of the battery pack is determined using time-series data of at least one environmental parameter and a water hazard risk prediction model. This includes determining the water hazard level of the battery pack based on time-series data of air pressure, humidity, temperature, hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration, and using the water hazard risk prediction model.

[0016] One possible approach involves implementing water immersion protection control for the battery pack based on the water immersion risk level, including: outputting a water immersion risk warning when the water immersion risk level is Level 1, wherein the water immersion risk warning is used to prompt maintenance of the battery pack.

[0017] Based on the above technical means, although the battery pack is less affected under the level 1 water immersion risk, there are still potential hazards that require maintenance of the output battery pack. This prompts users to identify potential problems in advance and ensure the stable and safe operation of the battery pack in the future.

[0018] One possible approach, based on the water wading risk level, includes water wading protection control of the battery pack, which further includes: in the case of a water wading risk level of level 2, sending an electrical signal to the shape memory polymer seal inside the battery pack to cause the shape memory polymer seal to change from a compressed state to an expanded state; and reducing the charging power of the battery pack.

[0019] Based on the aforementioned technical means, the battery pack, under normal circumstances, can maintain good performance and stability when charged according to its designed power. However, when the battery pack is in a humid environment with a level 2 water immersion risk, its internal structure and electrical performance may be potentially affected. Therefore, by reducing the charging power of the battery pack, the internal current can be reduced, thereby reducing the battery's heat generation and preventing a sharp decline in battery performance due to overheating and other problems. This effectively reduces the probability of battery pack short circuits, bulging, and other malfunctions, ensuring the safety of both the battery pack and the vehicle.

[0020] One possible approach, based on the water wading risk level, includes water wading protection control of the battery pack, which further includes: in the case of a water wading risk level of three, controlling the high-voltage relay of the vehicle to disconnect, thereby cutting off the high-voltage circuit between the battery pack and the load; and activating the emergency ventilation device to expel the gas inside the battery pack.

[0021] Based on the aforementioned technical measures, when the water wading risk level is Level III, it indicates that the battery pack is in an extremely dangerous situation. The vehicle must immediately activate a series of emergency protection measures to ensure the safety of personnel and the vehicle. By controlling the vehicle's high-voltage relay to disconnect, the high-voltage circuit between the battery pack and the load is severed, preventing abnormal current flow and avoiding a series of serious consequences caused by a short circuit. Furthermore, by activating the emergency ventilation system, utilizing efficient ventilation ducts and powerful fans to create a strong airflow, the gas inside the battery pack is rapidly extracted, keeping the gas inside the battery pack fresh and reducing the concentration of flammable, explosive, and harmful gases. This effectively reduces the risk of battery thermal runaway and protects the safety of the battery pack.

[0022] According to a second aspect of this application, an airtightness testing device for a vehicle battery pack is provided. The device includes a determining unit and a testing unit. The determining unit is configured to determine the rate of change of at least one environmental parameter based on at least one environmental parameter inside the vehicle battery pack; the environmental parameter is air pressure, humidity, temperature, or gas concentration. The testing unit is configured to perform airtightness testing on the battery pack based on time-series parameter data of each of the at least one environmental parameter and an airtightness testing model, when the rate of change of the at least one environmental parameter is greater than a preset rate of change.

[0023] In one possible approach, the determining unit includes a correction subunit and a determining subunit. The correction subunit is used to correct the air pressure based on the altitude of the battery pack and the ambient temperature. The determining subunit is used to determine the rate of change of air pressure using the corrected air pressure.

[0024] In one possible approach, the correction subunit is specifically used to: determine the temperature difference between the external ambient temperature and the reference temperature; determine the product of the temperature difference and the temperature compensation coefficient as a first compensation coefficient; determine the altitude difference between the altitude and the reference altitude; determine the product of the altitude difference and the altitude compensation coefficient as a second compensation coefficient; and determine the corrected air pressure based on the first compensation coefficient, the second compensation coefficient, and the air pressure.

[0025] In one possible approach, the determining unit is further configured to, in the event of an airtightness anomaly in the battery pack, determine the water immersion risk level of the battery pack based on time-series parameter data of at least one environmental parameter and a water immersion risk prediction model; and, based on the water immersion risk level, implement water immersion protection control for the battery pack.

[0026] In one possible approach, the gas concentrations include hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration. Based on this, a unit is defined, specifically used to determine the water immersion risk level of the battery pack based on time-series data of gas pressure, humidity, temperature, hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration, and a water immersion risk prediction model.

[0027] In one possible embodiment, the detection unit includes a function to output a water wading risk warning when the water wading risk level is Level 1, wherein the water wading risk warning is used to prompt the battery pack to be inspected.

[0028] In one possible approach, the detection unit includes the ability to send an electrical signal to a shape memory polymer seal embedded in the battery pack when the water wading risk level is Level 2, causing the shape memory polymer seal to change from a compressed state to an expanded state; thereby reducing the charging power of the battery pack.

[0029] In one possible embodiment, the detection unit includes functions for controlling the high-voltage relay of the vehicle to disconnect in the event of a level 3 wading risk, thereby cutting off the high-voltage circuit between the battery pack and the load; and activating an emergency ventilation device to expel gas from the battery pack.

[0030] According to a third aspect provided in this application, a battery pack is provided, which is equipped with the airtightness detection device for the vehicle battery pack described in the second aspect above.

[0031] According to the fourth aspect provided in this application, a vehicle is provided which is equipped with the airtightness detection device for the vehicle battery pack described in the second aspect above, or the vehicle is equipped with the battery pack described in the third aspect above.

[0032] According to a fifth aspect of this application, an electronic device is provided, comprising: a processor; and a memory for storing processor-executable instructions. The processor is configured to execute instructions to implement the airtightness detection method for a vehicle battery pack according to the first aspect and any possible embodiment thereof.

[0033] According to a sixth aspect provided in this application, a computer-readable storage medium is provided that, when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform the airtightness detection method for a vehicle battery pack as described in the first aspect and any possible implementation thereof.

[0034] According to the seventh aspect provided in this application, a computer program product is provided, the computer program product including computer instructions, which, when executed on an electronic device, cause the electronic device to perform the airtightness detection method for a vehicle battery pack described in the first aspect and any possible implementation thereof.

[0035] It should be noted that the technical effects of any of the implementation methods in aspects two through seven can be found in the technical effects of the corresponding implementation methods in aspect one, and will not be repeated here.

[0036] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of a vehicle battery pack airtightness testing system provided in an embodiment of this application; Figure 2 A schematic diagram showing the installation positions of various sensors and shape memory polymer seals provided for embodiments of this application; Figure 3 A schematic flowchart illustrating a method for testing the airtightness of a vehicle battery pack, provided in an embodiment of this application; Figure 4 A schematic diagram of the structure of a vehicle battery pack airtightness testing device provided in an embodiment of this application; Figure 5 This is a block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0039] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0040] In the embodiments of this application, the words "exemplary," "for example," or "for instance" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the words "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a specific manner.

[0041] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0042] like Figure 1 As shown in the figure, an airtightness testing system for a vehicle battery pack provided in this application includes: a battery management system (BMS) 101, a battery pack 102, and a sensor 103 deployed in a vehicle 100. The BMS 101 communicates with the battery pack 102 and the sensor 103 via a serial peripheral interface (SPI) or an inter-integrated circuit (I²C) bus.

[0043] The sensor 103 may include a pressure sensor, a temperature and humidity sensor, a gas concentration sensor, and a water immersion sensor. The pressure sensor may include, but is not limited to: a piezoresistive pressure sensor (such as a MEMS pressure sensor), a capacitive pressure sensor, and a piezoelectric pressure sensor; the water immersion sensor may include, but is not limited to: a contact water immersion sensor and a capacitive water immersion sensor.

[0044] In this embodiment, the aforementioned sensors are installed inside the battery pack 102 housing. Specifically, the battery pack 102 may include multiple battery modules, each battery module being equipped with at least one pressure sensor to monitor the pressure inside the battery pack 102; temperature and humidity sensors may be configured at the contact points between the battery pack 102 and the inner wall of the battery pack 102 cover, as well as at the interfaces of the battery pack 102 connectors, to monitor the temperature and humidity inside the battery pack 102; gas concentration sensors may be configured near the exhaust valve of the battery pack 102 and at the sealing edge of the battery pack 102 to monitor the types of abnormal gases (such as carbon dioxide (CO2), hydrogen (H2), etc.) inside the battery pack 102 and their corresponding gas concentrations; and water immersion sensors may be configured near the drain hole at the bottom of the battery pack 102 to detect whether water has entered the battery pack 102.

[0045] In one example, Figure 2 A schematic diagram showing the installation locations of each sensor is provided. Figure 2 As shown, battery pack 103 includes four battery modules. Battery modules 1, 3, and 4 are respectively equipped with pressure sensors 1, 4, and 5, while battery module 2 is equipped with pressure sensors 2 and 3. Additionally, a pressure sensor 6 is installed at the interface of the connector plug in battery pack 102.

[0046] Continue reading Figure 2 A temperature and humidity sensor is installed at the top of the center of the battery pack 102; a gas concentration sensor 1 and a gas concentration sensor 2 are installed in the battery pack 102, with the gas concentration sensor installed near the exhaust valve; a water immersion sensor is installed at the bottom of the battery pack 102.

[0047] Optionally, the number and parameter requirements of the aforementioned sensors can be determined based on the airtightness testing needs. For example, each battery module can be configured with at least one barometric pressure sensor, with a measurement range between 0 kPa and 50 kPa, a measurement range of ±5 kPa, and a measurement accuracy of ±1 Pa. As another example, the number of temperature and humidity sensors can be one or two, with a temperature measurement accuracy of ±0.5 degrees Celsius (°C) and a humidity measurement accuracy of ±2% relative humidity (RH).

[0048] In this embodiment, a shape memory polymer (SMP) seal is installed inside the battery pack 102. The core function of the SMP seal is to actively recover from a temporarily compressed transport state to a preset working state (such as an expanded state) under specific stimuli, thereby achieving efficient and reliable sealing or filling to prevent moisture from continuously seeping into the battery pack 102.

[0049] Specifically, when the SMP seal is powered on, the conductive network formed by its built-in conductive fillers such as carbon fiber and graphene generates a Joule heating effect, efficiently and uniformly converting electrical energy into heat energy. As heat energy accumulates, the temperature of the SMP seal rises above the glass transition temperature (Tg). At this point, the microstructure inside the SMP seal material undergoes a fundamental change: the polymer chains of the SMP seal change from a glassy state (hard and brittle, fixed and temporarily contracted) to a highly elastic state (soft and recoverable) where the chain segments can move freely. After entering the highly elastic state, the stress of the preset shape (such as the expanded sealing state) stored inside the SMP seal is released, driving the material to automatically recover to the designed expanded shape and complete the sealing action. After the shape recovery is completed, the power is disconnected, and the temperature of the SMP seal drops below Tg. Its polymer chain segment mobility decreases, and the SMP seal material re-solidifies and maintains the expanded sealing shape to prevent moisture from continuously penetrating into the battery pack 102. The above process is the electrothermal phase change process of the SMP seal.

[0050] The SMP seals can be placed in leak-prone areas of the battery pack 102, such as the joints between battery modules, the junctions of the casing, and the interfaces of connecting plugs. Due to the limited internal space of the battery pack 102, the SMP seals can be designed as thin sheets or strips embedded in the sealing grooves. For example... Figure 2 As shown, SMP seal 1, SMP seal 2, SMP seal 3 and SMP seal 4 are installed inside the battery pack 102.

[0051] Optionally, the Tg of the SMP seal can be set according to the operating environment of the battery pack 102 (generally between -40℃ and 85℃). For example, the Tg value can be between 45℃ and 60℃. This not only avoids the SMP seal from being accidentally triggered to return to its expanded state at low temperatures (such as when the battery is parked in winter), but also allows the SMP seal to quickly heat up to Tg after being powered on.

[0052] Optionally, SMP seals may include, but are not limited to: polyurethane-based SMP (containing carbon fiber), epoxy resin-based SMP (containing graphene), and silicone rubber-modified SMP. Polyurethane-based SMP is suitable for temperate environments, with a corresponding Tg range of 50℃-55℃ and a deformation range of 300%-400%; epoxy resin-based SMP is suitable for high-temperature and high-humidity environments, with a corresponding Tg range of 55℃-60℃ and a water swelling rate ≤3%; silicone rubber-modified SMP is suitable for cold environments, with a corresponding Tg range of 45℃-50℃.

[0053] In some embodiments, sensor 103 can collect environmental parameters (air pressure, humidity, temperature, and gas concentration) within battery pack 102 in real time and send these parameters to BMS 101. Accordingly, upon receiving the environmental parameters, BMS 101 can determine the rate of change of each of the at least one environmental parameter, and if the rate of change of any of the at least one environmental parameter is greater than its corresponding preset rate of change, perform airtightness testing on battery pack 102 based on the time-series parameter data of each of the at least one environmental parameter and an airtightness detection model.

[0054] In some embodiments, when an airtightness anomaly is detected in the battery pack 102, the BMS 101 can determine the water immersion risk level of the battery pack 102 based on time-series parameter data of at least one environmental parameter and a water immersion risk prediction model. Subsequently, the BMS 101 can implement water immersion protection control on the battery pack 102 based on the water immersion risk level.

[0055] For example, if an airtightness abnormality is detected in the battery pack 102, the BMS 101 can activate its built-in low-voltage drive output module based on the water immersion risk level, instantly outputting an electrical signal. This signal can directly reach the conductive interface of the SMP seal through the vehicle's low-voltage wiring harness to trigger an electrothermal phase change in the SMP seal. Upon receiving the electrical signal, the SMP seal undergoes a polymer structure phase change through electrothermal conversion, achieving shape recovery (i.e., recovering from a fixed temporary contracted state to an expanded state), thereby sealing the gaps in the battery pack 102 and preventing continuous water infiltration into the battery pack 102.

[0056] The airtightness detection system for the vehicle battery pack provided in this application embodiment can be configured in a vehicle. A vehicle can also be referred to as a vehicle, mobile carrier, electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), fuel cell vehicle (FCV), autonomous vehicle, intelligent and connected vehicle (ICV), driverless vehicle, etc.

[0057] In this application, the vehicle can be a sedan, a sport utility vehicle (SUV), a truck, an electric vehicle, a motorcycle, a tricycle, a special vehicle (such as an ambulance, fire truck, police car, etc.), a driverless taxi, an intelligent connected bus, an autonomous logistics vehicle, an electric truck, etc. Furthermore, this method is also applicable to various special-purpose vehicles, such as agricultural vehicles, mining vehicles, forestry vehicles, airport vehicles, and port vehicles. This application does not impose specific limitations in this regard.

[0058] For ease of understanding, the airtightness testing method for the vehicle battery pack provided in this application will be described in detail below with reference to the accompanying drawings.

[0059] Figure 3 A schematic flowchart illustrating a method for testing the airtightness of a vehicle battery pack, provided in an embodiment of this application; S301. Based on at least one environmental parameter inside the vehicle battery pack, determine the rate of change of each of the at least one environmental parameter.

[0060] The environmental parameters can include: air pressure, humidity, temperature, and gas concentration. Air pressure can be obtained using an air pressure sensor, humidity and temperature can be obtained using a humidity and temperature sensor, and gas concentration can be obtained using a gas concentration sensor.

[0061] The gas concentration may include, but is not limited to: H2 concentration, CO2 concentration, carbon monoxide (CO) concentration, and concentrations of various hydrocarbon gases (such as methane (CH4), ethylene (C2H4), ethane (C2H6), etc.).

[0062] In some embodiments, the sensor can collect real-time data on air pressure, humidity, temperature, and gas concentration within the battery pack and transmit these data to the BMS. Accordingly, upon receiving the air pressure, humidity, temperature, and gas concentration data, the BMS can preprocess these parameters. Subsequently, the BMS can determine the rate of change of each parameter—namely, the rate of change of air pressure, humidity, temperature, and gas concentration.

[0063] The altitude and temperature variations of the battery pack significantly affect its internal air pressure, directly impacting the accuracy of airtightness testing and the reliability of the abnormal gas monitoring system. Therefore, the air pressure value needs to be corrected based on the battery pack's altitude and temperature to ensure the accuracy of the air pressure change rate calculation. Based on this, the BMS can use an air pressure compensation function to correct the pre-processed air pressure based on the battery pack's altitude and ambient temperature, and then use the corrected air pressure to determine the air pressure change rate.

[0064] Specifically, the BMS can determine the temperature difference between the ambient temperature and the reference temperature, and use the product of this temperature difference and a temperature compensation coefficient as the first compensation coefficient. Simultaneously, the BMS can determine the altitude difference between the altitude and the reference altitude, and use the product of this altitude difference and an altitude compensation coefficient as the second compensation coefficient. Finally, based on the first compensation coefficient, the second compensation coefficient, and the air pressure, the BMS can determine the corrected air pressure.

[0065] For example, the air pressure compensation function is shown in Formula 1 below.

[0066] (Formula 1) in, This indicates the corrected air pressure; Indicates the original air pressure; Indicates the external ambient temperature; This indicates the reference temperature (or standard temperature), which can be 25 degrees Celsius (°C). Indicates altitude; This indicates the baseline altitude (or reference altitude), which can be 0 meters (m). Indicates the temperature compensation coefficient; Indicates the altitude compensation coefficient; Indicates the first compensation coefficient; This represents the second compensation coefficient.

[0067] Optionally, preprocessing may include, but is not limited to, filtering and denoising, and outlier handling. Filtering and denoising can be performed using algorithms such as Kalman filtering and moving average filtering. For example, because air pressure is highly sensitive to changes in the airtightness of the battery pack and is easily affected by random disturbances, a Kalman filter can be used to filter air pressure, thereby dynamically eliminating noise while preserving the true trend of air pressure changes. As another example, temperature and humidity parameters typically exhibit slowly varying characteristics; therefore, a moving average filter can be used to filter temperature and humidity, thereby smoothing data fluctuations while preserving their patterns of change.

[0068] Optionally, the sampling frequency of the sensors for acquiring various environmental parameters can be determined according to actual needs. For example, the sampling frequency can be 1 Hz, 3 Hz, or 5 Hz, etc., without limitation.

[0069] S302. When the rate of change of at least one environmental parameter is greater than the preset rate of change of the parameter, the battery pack is subjected to air tightness testing based on the time-series parameter data of each of the at least one environmental parameter and the air tightness testing model.

[0070] In some embodiments, if the rate of change of any parameter among the rate of change of air pressure, rate of change of humidity, rate of change of temperature, and rate of change of gas concentration corresponding to each abnormal gas is greater than the rate of change of its corresponding preset parameter, the BMS can input the time series parameters of air pressure, humidity, temperature, and gas concentration into the air tightness detection model to obtain the air tightness score of the battery pack output by the air tightness detection model, and determine whether there is an air tightness abnormality in the battery pack based on the air tightness score.

[0071] Optionally, the time-series parameter data of the above-mentioned environmental parameters can be parameter data within 10 seconds (s), parameter data within 20 seconds, or parameter data within 30 seconds. This application does not limit this.

[0072] Optionally, the preset parameter change rate corresponding to each of the above environmental parameters can be determined according to the actual situation. For example, the preset parameter change rate corresponding to the air pressure change rate can be 50 Pa / min, 100 Pa / min or 200 Pa / min, etc., and the preset parameter change rate corresponding to the humidity change rate can be 15RH / s, 20RH / s or 30RH / s, etc., and this application does not limit it in this way.

[0073] Optionally, the airtightness detection model can be a convolutional neural network (CNN) model, a long short-term memory network (LSTM) model, a temporal convolutional network (TCN) model, or a hybrid CNN and LSTM network model, etc., and this application does not limit it.

[0074] For example, assume the preset parameter change rate corresponding to the air pressure change rate is 200 Pa / min. Based on this, if the air pressure change rate is 210 Pa / min, the BMS can input the time-series air pressure, humidity, and temperature parameters, as well as the gas concentration time-series parameters corresponding to each abnormal gas, within 20 seconds into the airtightness detection model to obtain the airtightness score of the battery pack output by the model. If the airtightness score is 0, it indicates that the battery pack has an airtightness abnormality; if the airtightness score is 1, it indicates that the battery pack is internally normal and there is no airtightness failure.

[0075] In some embodiments, when the air tightness score of the battery pack indicates an air tightness abnormality, the sensor can switch to a high-speed sampling mode (e.g., switch from a sampling frequency of 1 Hz to a sampling frequency of 10 Hz) and send air pressure, temperature, humidity and gas concentration to the BMS in real time.

[0076] Based on the above technical solution, this application can monitor the rate of change of different environmental parameters inside the vehicle battery pack in real time, and quantify the intensity of parameter fluctuations through the rate of change of each environmental parameter, providing clear triggering conditions for subsequent detection and avoiding missed or false detections. Furthermore, when the rate of change of any environmental parameter exceeds its corresponding preset parameter rate of change, it is determined that the battery pack has a "potential airtightness anomaly," triggering subsequent precise airtightness detection. This involves calling an airtightness detection model to perform battery pack airtightness detection. By providing the model with time-series parameter data from multiple environmental dimensions, the dynamic process of airtightness changes within the battery pack can be fully covered, thereby improving the accuracy of battery airtightness detection.

[0077] In one optional implementation, when the BMS detects an airtightness anomaly in the battery pack, it can determine the water erosion risk level of the battery pack based on time-series parameter data of at least one environmental parameter and a water erosion risk prediction model. Then, the BMS can implement water erosion protection control for the battery pack based on the water erosion risk level.

[0078] In some embodiments, when the airtightness score of the battery pack indicates an airtightness anomaly, the BMS can input time-series data of air pressure, humidity, and temperature, as well as the gas concentrations corresponding to each abnormal gas (such as time-series data of hydrogen, carbon dioxide, and carbon monoxide), into the water wading risk prediction model to obtain the water wading risk level of the battery pack output by the model. Subsequently, the BMS can perform water wading protection control on the battery pack based on the water wading risk level.

[0079] The water risk levels can be categorized into Level 1, Level 2, and Level 3. The water risk level is positively correlated with the severity of water damage to the battery pack; Level 2 water risk is more severe than Level 1, and Level 3 water risk is more severe than Level 2.

[0080] For example, when the water risk level is Level 1, the BMS can output a water risk warning, which is used to prompt the battery pack to be inspected.

[0081] For example, in the event of a Level 2 flood risk, the BMS can reduce the battery pack's charging power (e.g., reduce the charging power to 30%) to disable fast charging; the BMS can also output voice prompts. These voice prompts are used to alert the user to an abnormal battery pack status and suggest stopping the vehicle for inspection.

[0082] In addition, the BMS can activate its built-in low-voltage drive output module to instantly output an electrical signal. This signal can be directly transmitted to the conductive interface of the SMP seal via the vehicle's low-voltage wiring harness to trigger an electrothermal phase change in the SMP seal. Upon receiving the signal, the SMP seal undergoes an electrothermal phase change, restoring its shape (from a fixed temporary contracted state to an expanded state) to seal the gaps in the battery pack and prevent moisture from continuously seeping into it. After sealing, if the rate of change in air pressure is less than or equal to the corresponding preset parameter rate of change, the protection and control of the battery pack is effective. If the rate of change in air pressure is greater than the corresponding preset parameter rate of change, the BMS can trigger an audible and visual alarm to prompt the user to immediately move the vehicle away from the flooded area. Simultaneously, the vehicle controller can disconnect the high-voltage circuit and perform maintenance.

[0083] For example, in the event of a Level 3 water wading risk, the BMS can send a warning message to the vehicle controller. Correspondingly, the vehicle controller can disconnect the vehicle's high-voltage relay to cut off the high-voltage circuit between the battery pack and the load; simultaneously, the BMS can activate the emergency ventilation system to expel gas from the battery pack; the vehicle controller can also upload the vehicle's location information, battery pack airtightness information, and water wading information to the cloud via a telematics box (T-BOX) to support after-sales big data analysis and false alarm optimization.

[0084] Based on the above technical solutions, the time-series parameter data of various environmental parameters in this application (such as the trend of air pressure decrease, the rate of increase of humidity, and the gas concentration change curve) can reflect the severity of airtightness anomalies (such as rapid leakage vs. slow leakage), and can provide an accurate basis for the water immersion risk level of the battery pack. In addition, by predicting the water immersion risk of the battery pack in advance through the water immersion risk prediction model, serious failures such as battery short circuits and corrosion caused by water intrusion can be avoided in advance.

[0085] like Figure 4 As shown in the figure, an airtightness testing device for a vehicle battery pack provided in this application embodiment includes: The determining unit 401 is used to determine the parameter change rate of at least one environmental parameter based on at least one environmental parameter inside the vehicle battery pack; the environmental parameter is air pressure, humidity, temperature or gas concentration.

[0086] The detection unit 402 is used to perform airtightness detection on the battery pack based on the time-series parameter data of each of the at least one environmental parameter and the airtightness detection model when the parameter change rate of at least one environmental parameter is greater than the preset parameter change rate.

[0087] In one possible embodiment, the determining unit 401 includes a correction subunit and a determining subunit. The correction subunit is used to correct the air pressure based on the altitude of the battery pack and the ambient temperature. The determining subunit is used to determine the rate of change of air pressure using the corrected air pressure.

[0088] In one possible approach, the correction subunit is specifically used to: determine the temperature difference between the external ambient temperature and the reference temperature; determine the product of the temperature difference and the temperature compensation coefficient as a first compensation coefficient; determine the altitude difference between the altitude and the reference altitude; determine the product of the altitude difference and the altitude compensation coefficient as a second compensation coefficient; and determine the corrected air pressure based on the first compensation coefficient, the second compensation coefficient, and the air pressure.

[0089] In one possible approach, the determining unit 401 is further configured to determine the water immersion risk level of the battery pack based on time-series parameter data of at least one environmental parameter and a water immersion risk prediction model when the battery pack has an airtightness anomaly; and to perform water immersion protection control on the battery pack based on the water immersion risk level.

[0090] In one possible approach, the gas concentrations include hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration. Based on this, unit 401 is specifically used to determine the water immersion risk level of the battery pack based on time-series data of gas pressure, humidity, temperature, hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration, and a water immersion risk prediction model.

[0091] In one possible embodiment, the detection unit 402 is further configured to output a water wading risk warning when the water wading risk level is Level 1, wherein the water wading risk warning is used to prompt the battery pack to be inspected.

[0092] In one possible approach, the detection unit includes the ability to send an electrical signal to a shape memory polymer seal embedded in the battery pack when the water wading risk level is Level 2, causing the shape memory polymer seal to change from a compressed state to an expanded state; and to reduce the charging power of the battery pack; wherein the water wading severity of Level 2 water wading risk is higher than that of Level 1 water wading risk.

[0093] In one possible embodiment, the detection unit 402 includes the following: in the event of a level 3 wading risk, controlling the high-voltage relay of the vehicle to disconnect, thereby cutting off the high-voltage circuit between the battery pack and the load; activating the emergency ventilation device to expel the gas inside the battery pack; wherein the severity of wading risk at level 3 is higher than that at level 2.

[0094] like Figure 5As shown in the embodiments of this application, an electronic device includes, but is not limited to, a processor 501 and a memory 502.

[0095] The memory 502 described above is used to store the executable instructions of the processor 501. It is understood that the processor 501 is configured to execute instructions to implement the airtightness detection method for the vehicle battery pack in the above embodiment.

[0096] It should be noted that those skilled in the art will understand that Figure 5 The electronic device structure shown does not constitute a limitation on the electronic device; the electronic device may include, but is not limited to, other electronic devices. Figure 5 This may indicate more or fewer components, or combinations of certain components, or different component arrangements.

[0097] Processor 501 is the control center of the electronic device. It connects various parts of the electronic device via various interfaces and lines. By running or executing software programs and / or modules stored in memory 502, and by calling data stored in memory 502, it performs various functions and processes data, thereby providing overall monitoring of the electronic device. Processor 501 may include one or more processing units. Optionally, processor 501 may integrate an application processor and a modem processor. The application processor mainly handles the operating system, user interface, and applications, while the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into processor 501.

[0098] The memory 502 can be used to store software programs and various data. The memory 502 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, application programs required by at least one functional module (such as a determination unit, processing unit, etc.), etc. Furthermore, the memory 502 may include high-speed random access memory and may also include non-volatile memory. For example, non-volatile memory may include at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0099] In an exemplary embodiment, a computer-readable storage medium including instructions is also provided, such as a memory 502 including instructions, which can be executed by a processor 501 of an electronic device to implement the methods in the above embodiments.

[0100] Optionally, the computer-readable storage medium may be a non-transitory computer-readable storage medium, such as a read-only memory (ROM), random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device.

[0101] In an exemplary embodiment, this application also provides a computer program product including one or more instructions, which can be executed by a processor 501 of an electronic device to perform the methods described above.

[0102] It should be noted that when one or more instructions in the computer-readable storage medium or computer program product are executed by the processor of an electronic device, they implement the various processes of the above method embodiments and achieve the same technical effect as the above method. To avoid repetition, they will not be described again here.

[0103] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0104] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0105] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0106] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0107] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0108] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for testing the airtightness of a vehicle battery pack, characterized in that, The airtightness testing method for the vehicle battery pack includes: Based on at least one environmental parameter inside the vehicle battery pack, determine the rate of change of at least one of the environmental parameters, wherein the environmental parameter is air pressure, humidity, temperature or gas concentration; If the rate of change of at least one of the environmental parameters is greater than the preset rate of change of the parameter, the battery pack is subjected to air tightness testing based on the time-series parameter data of at least one of the environmental parameters and the air tightness testing model.

2. The method for testing the airtightness of a vehicle battery pack according to claim 1, characterized in that, Determining the rate of change of each of the at least one environmental parameter based on at least one environmental parameter within the vehicle battery pack includes: The air pressure is adjusted based on the altitude of the battery pack and the ambient temperature. The rate of change of air pressure is determined using the corrected air pressure.

3. The method for testing the airtightness of a vehicle battery pack according to claim 2, characterized in that, The step of correcting the air pressure based on the altitude and ambient temperature of the battery pack includes: Determine the temperature difference between the external ambient temperature and the reference temperature; The product of the temperature difference and the temperature compensation coefficient is determined as the first compensation coefficient. Determine the altitude difference between the stated altitude and the reference altitude; The product of the altitude difference and the altitude compensation coefficient is determined as the second compensation coefficient. The corrected air pressure is determined based on the first compensation coefficient, the second compensation coefficient, and the air pressure.

4. The method for testing the airtightness of a vehicle battery pack according to claim 1, characterized in that, The airtightness testing method for the vehicle battery pack further includes: In the event of an airtightness anomaly in the battery pack, the water immersion risk level of the battery pack is determined based on the time-series parameter data of each of the at least one environmental parameter and the water immersion risk prediction model. Based on the aforementioned water immersion risk level, water immersion protection control is implemented for the battery pack.

5. The method for testing the airtightness of a vehicle battery pack according to claim 4, characterized in that, The gas concentrations include hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration; The determination of the water hazard level of the battery pack based on the time-series parameter data of each of the at least one environmental parameter and the water hazard prediction model includes: Based on time-series data of air pressure, humidity, temperature, hydrogen concentration, carbon dioxide concentration, and carbon monoxide concentration, and the water immersion risk prediction model, the water immersion risk level of the battery pack is determined.

6. The method for testing the airtightness of a vehicle battery pack according to claim 4, characterized in that, The water immersion protection control of the battery pack based on the water immersion risk level includes: When the water risk level is Level 1, a water risk warning is issued, which is used to prompt the battery pack to be inspected and repaired.

7. The method for testing the airtightness of a vehicle battery pack according to claim 4, characterized in that, The water immersion protection control of the battery pack based on the water immersion risk level further includes: When the water risk level is Level 2, an electrical signal is sent to the shape memory polymer seal inside the battery pack to cause the shape memory polymer seal to change from a compressed state to an expanded state. Reduce the charging power of the battery pack.

8. The method for testing the airtightness of a vehicle battery pack according to claim 4, characterized in that, The water immersion protection control of the battery pack based on the water immersion risk level further includes: When the water wading risk level is level three, the high-voltage relay of the vehicle is disconnected to cut off the high-voltage circuit between the battery pack and the load. Activate the emergency ventilation device to expel the gas inside the battery pack.

9. A device for detecting the airtightness of a vehicle battery pack, characterized in that, The airtightness testing device for the vehicle battery pack includes: The determining unit is configured to determine the rate of change of at least one environmental parameter based on at least one environmental parameter inside the vehicle battery pack, wherein the environmental parameter is air pressure, humidity, temperature or gas concentration; The detection unit is used to perform airtightness detection on the battery pack based on the time-series parameter data of each of the at least one environmental parameter and the airtightness detection model when the parameter change rate of at least one of the environmental parameters is greater than the preset parameter change rate.

10. The airtightness testing device for a vehicle battery pack according to claim 9, characterized in that, The determining unit includes: a correction subunit and a determining subunit; The correction subunit is used to correct the air pressure based on the altitude of the battery pack and the external ambient temperature. The determining subunit is used to determine the rate of change of air pressure using the corrected air pressure.

11. A battery pack, characterized in that, The battery pack is equipped with the airtightness detection device for the vehicle battery pack as described in claim 9 or 10.

12. A vehicle, characterized in that, The vehicle is equipped with the airtightness detection device for the vehicle battery pack as described in claim 10, or the vehicle is equipped with the battery pack as described in claim 11.

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