Battery device and partial discharge monitoring method

Abstract

The invention discloses a battery device and a partial discharge monitoring method, the battery device comprises a single battery, and the surface of the single battery is provided with an insulating layer; the ultrasonic sensor is arranged on one side, far away from the single battery, of the insulating layer; the signal acquisition assembly and the ultrasonic sensor are separately arranged, and the signal acquisition assembly is coupled to the ultrasonic sensor; the detection assembly is coupled to the signal acquisition assembly; wherein the ultrasonic sensor is used for converting an ultrasonic signal generated by partial discharge of the single battery into a first voltage signal; the signal acquisition assembly is used for processing the first voltage signal and then outputting the processed first voltage signal to the detection assembly, and the detection assembly is used for carrying out operation processing on the processed first voltage signal to obtain a monitoring result representing partial discharge of the single battery. Therefore, online monitoring of partial discharge of the single battery can be realized, and the response speed is high, so that whether the insulation state of the battery is degraded or not can be pre-warned in real time.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery device and a method for monitoring partial discharge. Background Technology

[0002] With the rapid development of batteries, their applications have expanded beyond power batteries to include energy storage batteries, making battery system safety an increasingly important concern. Partial discharge is a crucial parameter reflecting battery insulation performance; it is a sign and manifestation of insulation degradation.

[0003] Currently, commonly used online partial discharge monitoring methods mainly include ultra-high frequency (UHF) and ultrasonic methods. However, the multi-layered metal casing of the battery module shields the UHF electromagnetic waves of internal partial discharge, especially under the complex electromagnetic wave and vibration conditions of the battery module, where the UHF sensor has poor anti-interference capability; while the ultrasonic sensor fixed externally has poor coupling effect, which is not conducive to the partial discharge monitoring of the battery. Summary of the Invention

[0004] This application proposes a battery device and a partial discharge monitoring method, which can not only monitor the partial discharge of individual cells, but also has a fast response speed and can provide real-time early warning of whether the battery insulation state has deteriorated.

[0005] The technical solution of this application is implemented as follows:

[0006] In a first aspect, embodiments of this application provide a battery device, including:

[0007] A single cell, with an insulating layer on its surface;

[0008] An ultrasonic sensor is positioned on the side of the insulating layer away from the individual battery cell.

[0009] The signal acquisition component is separately configured from the ultrasonic sensor and coupled to the ultrasonic sensor.

[0010] The detection component is coupled to the signal acquisition component;

[0011] The ultrasonic sensor is used to convert the ultrasonic signal generated by the partial discharge of a single cell into a first voltage signal; the signal acquisition component is used to process the first voltage signal and output it to the detection component; the detection component is used to perform calculations on the processed first voltage signal to obtain the monitoring results characterizing the partial discharge of the single cell.

[0012] Through the aforementioned technical means, since the ultrasonic sensor is placed on the insulating layer on the surface of the individual battery, the small distance between the ultrasonic sensor and the individual battery results in minimal signal attenuation caused by partial discharge, thus facilitating the monitoring of partial discharge in individual batteries. Then, a signal acquisition component, separately positioned from the ultrasonic sensor, processes the first voltage signal. This separate placement of the signal acquisition component and the ultrasonic sensor solves the space occupation problem, allowing the ultrasonic sensor to be placed inside the battery device without increasing its size, enabling the detection of partial discharge signals from individual batteries within the battery device. Furthermore, the detection component performs calculations on the processed first voltage signal, thereby enabling the monitoring of partial discharge in individual batteries. This not only achieves online monitoring of partial discharge in individual batteries but also, compared to insulation resistance monitoring, the ultrasonic sensor has a faster response speed, allowing for more timely prevention of insulation failure within individual batteries and providing real-time early warning of potential insulation degradation.

[0013] In some embodiments, the ultrasonic sensor includes a piezoelectric thin film structure, wherein the piezoelectric thin film structure includes a lower electrode sheet, a piezoelectric material layer, and an upper electrode sheet stacked sequentially.

[0014] Through the above-mentioned technical means, the ultrasonic sensor includes a piezoelectric thin film structure, which occupies little space when attached to a single cell, has a tight fit, and can match the outer contour of the single cell well. Based on the characteristics of high sensitivity, fast response speed, and good stability of the piezoelectric thin film structure, it is beneficial to realize the monitoring of partial discharge of single cells, thereby enabling real-time early warning of whether the insulation state of the battery has deteriorated.

[0015] In some embodiments, the piezoelectric thin film structure is a flexible structure.

[0016] Through the above-mentioned technical means, since the piezoelectric film structure is a flexible structure, it can be better attached to the single cell, occupying little space, with a tight bond, and can match the outer contour of the single cell well, which is conducive to realizing the partial discharge monitoring of the single cell.

[0017] In some embodiments, the ultrasonic sensor is disposed below the bottom R-corner region of the individual battery cell, and / or below the bottom planar region of the individual battery cell.

[0018] Through the above-mentioned technical means, since the vibration process of partial discharge can be transmitted, but the signal attenuation is relatively severe, and considering that the vibration direction is up and down, the ultrasonic sensor is placed below the bottom of the single cell (for example, below the bottom plane area and / or below the bottom R-corner area). At this time, the pressure generated by the partial discharge vibration is transmitted to the piezoelectric thin film structure in the ultrasonic sensor, making the piezoelectric thin film structure more susceptible to deformation, thus making it easier to detect vibration. This makes the measurement of the ultrasonic sensor more accurate. Moreover, based on the characteristics of piezoelectric thin film such as high sensitivity, fast response speed and good stability, it is beneficial to realize the monitoring of partial discharge of single cells.

[0019] In some embodiments, the number of individual battery cells is multiple, and the multiple individual battery cells are connected in series to form a battery module; the ultrasonic sensor is disposed in at least one of the following locations inside the battery module:

[0020] Below the bottom R-corner area of ​​the battery in the preset position inside the battery module;

[0021] Below the bottom plane area of ​​the battery in a preset position inside the battery module;

[0022] Below the bottom R-corner area of ​​the battery in a non-preset position inside the battery module;

[0023] Below the bottom plane area of ​​the battery in a non-preset position inside the battery module;

[0024] The preset position battery includes: the first-end single cell battery and / or the last-end single cell battery.

[0025] Using the above-mentioned technical means, considering that the vibration process of partial discharge can be transmitted and that the vibration direction is up and down, in order to avoid significant signal attenuation, the ultrasonic sensor is usually placed at the bottom of the individual battery inside the battery module. At this time, the pressure generated by the partial discharge vibration is transmitted to the ultrasonic sensor, making it easier for the ultrasonic sensor to sense the deformation and thus easier to detect the vibration, making the ultrasonic sensor measurement more accurate. Moreover, based on the characteristics of piezoelectric film such as high sensitivity, fast response speed and good stability, it is beneficial to realize the monitoring of partial discharge of individual batteries.

[0026] In some embodiments, the signal acquisition component is coupled to the ultrasonic sensor via a signal shielding channel.

[0027] By employing the aforementioned technical means, since the signals detected by the ultrasonic sensor are very weak (e.g., on the order of millivolts), they are easily subject to interference. In this case, a signal shielding channel is used to couple the signal acquisition component and the ultrasonic sensor, thereby enabling shielded signal transmission and improving anti-interference capabilities.

[0028] In some embodiments, the ultrasonic sensor is coupled to the signal acquisition component via a first acquisition line; wherein the battery device further includes a shielding element located around the first acquisition line.

[0029] Using the above-mentioned technical means, since the signal detected by the ultrasonic sensor is very weak (e.g., on the order of millivolts) and easily interfered with, the measure taken here is to add shielding elements, thereby achieving signal shielded transmission and improving anti-interference capability.

[0030] In some embodiments, the signal acquisition component includes a signal amplification circuit and an acquisition filtering circuit, wherein: the signal amplification circuit includes a first filtering circuit, a first operational amplifier circuit, and a second operational amplifier circuit, and the input terminal of the first filtering circuit is coupled to the ultrasonic sensor, the output terminal of the first filtering circuit is connected to the first operational amplifier circuit, the first operational amplifier circuit and the second operational amplifier circuit are cascaded, and are used to amplify and filter the first voltage signal to output a second voltage signal; the acquisition filtering circuit includes a signal acquisition circuit and a second filtering circuit, and the signal acquisition circuit is connected between the output terminal of the second operational amplifier circuit and the input terminal of the second filtering circuit, and is used to acquire and filter the second voltage signal to output the processed first voltage signal.

[0031] Through the aforementioned technical means, the signal amplification circuit can amplify and filter the first voltage signal. The signal filtering can remove low-frequency signals from the first voltage signal. Moreover, the signal amplification adopts a two-stage amplification circuit design, which can better achieve the preset amplification and enhancement of the signal, thereby ensuring the stability and reliability of the signal and reducing the probability of signal interference. Then, the acquisition and filtering circuit performs signal acquisition and filtering. It can first use analog-to-digital conversion to convert the continuous analog signal into a discrete digital signal, and then use signal filtering to remove high-frequency noise signals from the first voltage signal. This not only meets the sampling requirements of the cell partial discharge frequency band, but also obtains the final voltage signal used for partial discharge identification (i.e., the processed first voltage signal), which is beneficial for realizing the partial discharge monitoring of individual cells.

[0032] In some embodiments, the signal acquisition circuit employs a data acquisition element with a sampling rate of not less than 10 megabits per second.

[0033] Using the aforementioned technical means, and based on the Nyquist theorem, the signal sampling rate is typically required to be no less than 10 megahertz per second, according to the actual test results of the partial discharge frequency band of the battery cell, thereby meeting the sampling requirements of the partial discharge frequency band of the battery cell.

[0034] In some embodiments, the battery device further includes an alarm circuit, wherein the alarm circuit is connected to a detection component and is used to generate alarm information based on monitoring results, the alarm information being used to indicate the degree of partial discharge of a single cell.

[0035] Using the above-mentioned technical means, after obtaining the monitoring results characterizing the partial discharge of a single cell, the alarm component can be used to generate corresponding alarm information. Based on the alarm information, the degree of partial discharge of the single cell can be indicated, and the management personnel can be notified to repair the fault caused by partial discharge in a timely manner, thereby preventing insulation failure in a timely manner.

[0036] In some embodiments, the signal acquisition component is integrated into the battery detection device, and / or the detection component is integrated into the cluster-level battery management unit or the battery management system.

[0037] By using the above-mentioned technical means, the signal acquisition component and the ultrasonic sensor are set up separately, which solves the problem of component space occupation. This allows the ultrasonic sensor to be placed inside the battery device, while the signal acquisition component can be integrated with the existing battery detection device. The detection component can be integrated with the cluster-level battery management unit or battery management system, thereby reusing the existing control board, making reasonable use of resources, and reducing costs.

[0038] Secondly, embodiments of this application provide a partial discharge monitoring method, applied to a battery device as described in any one of the first aspects; the method includes:

[0039] The first voltage signal output by the ultrasonic sensor is obtained, wherein the first voltage signal is obtained by converting the ultrasonic signal generated by the ultrasonic sensor based on the partial discharge of a single battery cell;

[0040] The first voltage signal is processed by the signal acquisition component and then output to the detection component;

[0041] The first voltage signal after processing is processed by the detection component to obtain the monitoring results characterizing the partial discharge of a single cell.

[0042] Through the aforementioned technical means, since the ultrasonic sensor is placed on the insulating layer on the surface of the individual battery, the small distance between the ultrasonic sensor and the individual battery results in minimal signal attenuation caused by partial discharge, which is beneficial for monitoring the partial discharge of the individual battery. The separate arrangement of the signal acquisition component and the ultrasonic sensor not only solves the problem of component space occupation, but also allows the signal acquisition component to process the first voltage signal, such as through signal amplification, acquisition, and filtering, thereby improving the anti-interference capability during signal transmission and enhancing the signal-to-noise ratio. Furthermore, the detection component performs calculations on the processed first voltage signal to obtain the monitoring results characterizing the partial discharge of the individual battery. This not only enables online monitoring of the partial discharge of the individual battery, but also, compared to insulation resistance monitoring, the ultrasonic sensor has a faster response speed, enabling more timely prevention of insulation failure within the individual battery and providing real-time early warning of whether the battery insulation status has deteriorated.

[0043] In some embodiments, the detection component performs calculations on the processed first voltage signal to obtain a monitoring result characterizing the partial discharge of a single cell, including: extracting time-domain features from the processed first voltage signal to obtain a first time-domain feature; matching the first time-domain feature with a preset time-domain feature library to obtain a monitoring result characterizing the partial discharge of a single cell; wherein the preset time-domain feature library is used to store the correspondence between different time-domain features and monitoring results.

[0044] Using the above-mentioned technical means, after obtaining the time-domain signal (i.e., the "processed first voltage signal"), the first time-domain feature can be obtained by extracting time-domain features from the time-domain signal. The extracted first time-domain feature is then matched with a preset time-domain feature library to obtain the monitoring result characterizing the partial discharge of a single cell. Based on the extracted time-domain features, it can be determined whether the partial discharge exceeds the standard, thus enabling the monitoring of partial discharge of a single cell.

[0045] In some embodiments, the detection component performs computational processing on the processed first voltage signal to obtain a monitoring result characterizing the partial discharge of a single cell, including: performing a Fourier transform on the processed first voltage signal to determine the spectrum of the processed first voltage signal; extracting frequency domain features based on the spectrum of the processed first voltage signal to obtain a first frequency domain feature; and matching the first frequency domain feature with a preset frequency domain feature library to obtain a monitoring result characterizing the partial discharge of a single cell; wherein the preset frequency domain feature library is used to store the correspondence between different frequency domain features and monitoring results.

[0046] Using the above-mentioned technical means, after obtaining the time-domain signal (i.e., the "processed first voltage signal"), the time-domain signal can be transformed into the frequency domain by performing frequency domain transformation, such as wavelet transform, Fourier transform, or fast Fourier transform, in order to extract spectral components, such as the first frequency domain feature. The extracted first frequency domain feature is then matched with a preset frequency domain feature library to obtain the monitoring results characterizing the partial discharge of a single battery cell. Based on the extracted frequency domain features, it can be determined whether the partial discharge exceeds the standard, thus realizing the monitoring of partial discharge of a single battery cell.

[0047] In some embodiments, when the first time-domain feature is the average amplitude of the signal, the method further includes: when the average amplitude of the processed first voltage signal is less than a first threshold, the monitoring result indicates that there is no partial discharge in the single cell; when the average amplitude of the processed first voltage signal is greater than or equal to the first threshold, the monitoring result indicates that there is partial discharge in the single cell.

[0048] Using the above technical means, taking the first time domain feature as the average amplitude of the signal as an example, for the average amplitude of the processed first voltage signal, if the average amplitude of the signal is less than the first threshold, it indicates that the insulation is normal. At this time, the monitoring result indicates that there is no partial discharge in the single cell. If the average amplitude of the signal is greater than or equal to the first threshold, it indicates that the insulation is abnormal. At this time, the monitoring result indicates that there is partial discharge in the single cell. At this time, the alarm information can be further reported to notify the management personnel to repair the fault caused by the partial discharge in time, so as to prevent insulation failure in time.

[0049] In some embodiments, when the monitoring result indicates that a single cell has partial discharge, the method further includes: when the average amplitude of the processed first voltage signal is greater than or equal to a first threshold and less than a second threshold, the alarm component generates a first alarm message; when the average amplitude of the processed first voltage signal is greater than or equal to the second threshold and less than a third threshold, the alarm component generates a second alarm message; when the average amplitude of the processed first voltage signal is greater than or equal to the third threshold, the alarm component generates a third alarm message; wherein the first alarm message, the second alarm message, and the third alarm message are used to indicate different degrees of partial discharge in a single cell.

[0050] Using the aforementioned technical means, and taking the average amplitude of the signal as the first time-domain feature as an example, after obtaining the average amplitude of the processed first voltage signal, the degree of partial discharge in a single battery cell can be further determined based on the range of the average amplitude. Specifically, if the average amplitude is in the first range, a first alarm message is generated, indicating that the single battery cell has experienced mild partial discharge; if the average amplitude is in the second range, a second alarm message is generated, indicating that the single battery cell has experienced moderate partial discharge; if the average amplitude is in the third range, a third alarm message is generated, indicating that the single battery cell has experienced severe partial discharge, leading to insulation failure, and the fault point needs to be immediately disconnected. In this way, different alarm messages can indicate the different degrees of partial discharge in a single battery cell, and can also notify management personnel to repair faults caused by partial discharge in a timely manner, thereby preventing insulation failure in a timely manner.

[0051] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of this application. Attached Figure Description

[0052] Figure 1 A schematic diagram of the composition structure of a battery device provided in this application embodiment. Figure 1 ;

[0053] Figure 2 This is a schematic diagram illustrating an application scenario for the attachment position of an ultrasonic sensor, provided in an embodiment of this application.

[0054] Figure 3 This is a schematic diagram illustrating an application scenario of a piezoelectric thin film sensor provided in an embodiment of this application;

[0055] Figure 4 A schematic diagram of the composition structure of a battery device provided in this application embodiment. Figure 2 ;

[0056] Figure 5 A schematic diagram of the composition structure of a signal acquisition component provided in an embodiment of this application;

[0057] Figure 6 A schematic diagram of the composition structure of a signal amplification circuit provided in an embodiment of this application;

[0058] Figure 7 A schematic diagram of the composition structure of a battery device provided in this application embodiment. Figure 3 ;

[0059] Figure 8 This is a schematic diagram illustrating an application scenario of a battery device provided in an embodiment of this application;

[0060] Figure 9 A flowchart illustrating a partial discharge monitoring method provided in this application embodiment. Figure 1 ;

[0061] Figure 10 A flowchart illustrating a partial discharge monitoring method provided in this application embodiment. Figure 2 . Detailed Implementation

[0062] In order to gain a more detailed understanding of the features and technical content of the embodiments of this application, the implementation of the embodiments of this application will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of this application.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0064] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0065] It should also be noted that the terms "first, second, and third" used in the embodiments of this application are only used to distinguish similar objects and do not represent a specific order of objects. It is understood that "first, second, and third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0066] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0067] The following is a description of the relevant technologies used in this application.

[0068] Battery cells are an important component of batteries. New energy batteries are being used more and more widely in daily life and industry. For example, new energy vehicles equipped with batteries are already widely used. In addition, batteries are increasingly being used in the field of energy storage.

[0069] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0070] In this embodiment, the battery can be a single battery cell or a battery pack composed of multiple battery cells. A single battery cell is a basic unit capable of converting chemical energy into electrical energy, and can be used to manufacture battery modules or battery packs to supply power to electrical devices. A single battery cell can be a rechargeable battery, which is a battery cell that can be recharged after discharge to reactivate its active materials and continue to be used. A single battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and is not limited thereto.

[0071] In this embodiment, the battery may also be a single physical module comprising one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or mixed via a busbar.

[0072] With the widespread application of batteries in power batteries and energy storage, the replacement of gasoline-powered vehicles with new energy vehicles (such as electric vehicles) has become a trend in the automotive industry. In addition to focusing on the driving range of electric vehicles, consumers also attach great importance to the safety of their battery systems. Timely and effective detection of potential safety hazards in battery systems is a crucial measure to ensure consumer safety and the sustainable development of battery companies.

[0073] For example, taking high-voltage power equipment as an example, online monitoring of partial discharge mainly employs two methods: ultra-high frequency (UHF) and ultrasonic. The ultrasonic method (also known as "acoustic emission") uses a piezoelectric sensor mounted on the casing to monitor the ultrasonic signals generated when partial discharge occurs in the power equipment. It has no connection to the electrical circuit of the power equipment, is unaffected by electrical interference, and has strong anti-electromagnetic interference capabilities. The UHF method uses an antenna sensor to monitor the high-frequency electromagnetic wave signals generated by partial discharge, with the monitored electromagnetic wave frequency band mainly in the range of 300MHz to 3GHz. Since the interference electromagnetic pulse energy in the substation power field is mainly concentrated below 200MHz, the UHF method has strong anti-electromagnetic interference capabilities.

[0074] However, both ultra-high frequency (UHF) and ultrasonic methods require large monitoring devices, whose structural designs are unsuitable for deployment on battery modules. Furthermore, the multi-layered metal casing of the battery module shields against UHF electromagnetic waves from internal partial discharges, making the UHF sensor's anti-interference capability poor, especially under the complex electromagnetic wave and vibration conditions of the battery module. Conversely, externally mounted piezoelectric sensors have poor coupling, hindering online monitoring of battery partial discharges and preventing timely warnings of insulation degradation.

[0075] Based on this, this application provides a battery device and a partial discharge monitoring method. In this battery device, since the ultrasonic sensor is disposed on the insulating layer on the surface of the individual battery, the distance between the ultrasonic sensor and the individual battery is small. Moreover, based on the piezoelectric effect of the ultrasonic sensor, the signal attenuation caused by partial discharge is small, which is beneficial for monitoring the partial discharge of the individual battery. Then, the signal acquisition component and the ultrasonic sensor are separately disposed. The signal acquisition component processes the first voltage signal, which not only solves the problem of component space occupation, allowing the ultrasonic sensor to be placed inside the battery device without increasing the size of the battery device, but also detects the partial discharge signal of the individual battery inside the battery device. Furthermore, the processed first voltage signal has undergone signal amplification, acquisition, and filtering, which can also improve the anti-interference ability during signal transmission and improve the signal-to-noise ratio. Then, the detection component performs calculations on the processed first voltage signal, thereby enabling the monitoring of the partial discharge of the individual battery. This not only realizes online monitoring of the partial discharge of the individual battery, but also, compared with insulation resistance monitoring, the ultrasonic sensor has a faster response speed, which can prevent insulation failure inside the individual battery more promptly, and thus can provide real-time early warning of whether the battery insulation status has deteriorated.

[0076] The various embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0077] In one embodiment of this application, Figure 1 A schematic diagram of the composition structure of a battery device provided in this application embodiment. Figure 1 .like Figure 1 As shown, the battery device 10 may include:

[0078] A single cell 101, the surface of which is provided with an insulating layer;

[0079] An ultrasonic sensor 102 is disposed on the side of the insulating layer away from the individual battery cell.

[0080] The signal acquisition component 103 is separately configured from the ultrasonic sensor 102 and coupled to the ultrasonic sensor 102.

[0081] The detection component 104 is coupled to the signal acquisition component 103.

[0082] In this embodiment, the ultrasonic sensor 102 is used to convert the ultrasonic signal generated by the partial discharge of the single cell 101 into a first voltage signal; the signal acquisition component 103 is used to process the first voltage signal and output it to the detection component 104; the detection component 104 is used to perform calculation processing on the processed first voltage signal to obtain the monitoring result characterizing the partial discharge of the single cell 101.

[0083] In this application embodiment, the battery device 10 can be applied to medium- and high-voltage energy storage scenarios. For example, the battery device 10 can be applied to energy storage scenarios with a rated DC voltage ≥1000V.

[0084] In addition, in this embodiment, the battery device 10 mainly realizes online monitoring of partial discharge of the single cell 101. Partial discharge refers to discharge occurring only in a localized area of ​​a single cell, without penetrating the entire insulating layer on the surface of the cell under applied voltage. That is, the discharge occurs in or near a certain area of ​​an electrical device or insulating structure, and can be simply referred to as "partial discharge." Furthermore, partial discharge generally refers to the discharge or breakdown phenomenon within a localized area of ​​the insulating medium caused by uneven electric field distribution and excessively high local field strength in the insulating structure. It is a major cause of insulation degradation and an important sign and manifestation of degradation, closely related to the degradation and breakdown of insulating materials.

[0085] Based on different monitoring principles and methods, commonly used partial discharge monitoring methods include ultra-high frequency (UHF) and ultrasonic methods. However, both UHF and ultrasonic methods require large monitoring devices, whose structural designs are not suitable for deployment on individual battery cells. Especially for online partial discharge monitoring scenarios, existing monitoring methods require the deployment of many ultrasonic probes, which are easily affected by interference. Furthermore, the position and orientation of the probes need to be constantly adjusted during testing, which is not conducive to achieving online monitoring of battery partial discharge.

[0086] Thus, in this embodiment of the application, a battery device 10 is provided, which includes an ultrasonic sensor 102. The ultrasonic sensor 102 may be made of a piezoelectric thin film material, such as polyvinylidene fluoride (PVDF) piezoelectric thin film material.

[0087] In some embodiments, the ultrasonic sensor 102 may include a piezoelectric thin film structure, wherein the piezoelectric thin film structure includes a lower electrode sheet, a piezoelectric material layer and an upper electrode sheet stacked sequentially.

[0088] In this embodiment, the piezoelectric thin film structure can be attached to a single cell with minimal space occupation, achieve a tight bond, and perfectly match the outer contour of the single cell. Thus, based on the characteristics of the piezoelectric thin film, such as high sensitivity, fast response speed, and good stability, it is beneficial to realize partial discharge monitoring of the single cell 101, thereby enabling real-time early warning of whether the battery insulation state has deteriorated.

[0089] In some embodiments, the piezoelectric thin film structure can be a flexible structure. Because the piezoelectric thin film structure is flexible, it can be better attached to a single cell, occupying less space, achieving a tighter bond, and can well match the outer contour of the single cell, which is beneficial for monitoring partial discharge of the single cell.

[0090] In this embodiment, the ultrasonic sensor 102 can also be called a piezoelectric thin film sensor or simply a piezoelectric sensor. The ultrasonic sensor 102 may include a lower electrode sheet, a piezoelectric material layer, and an upper electrode sheet arranged in a stacked manner, primarily used to convert the generated ultrasonic signal into an electrical signal.

[0091] Understandably, in the embodiments of this application, when a piezoelectric PVDF polymer film (piezoelectric thin film) is stretched or bent, an electrical signal (charge or voltage) is generated between the upper and lower electrode surfaces of the film, and this signal is proportional to the deformation caused by stretching or bending. In other words, for a piezoelectric thin film, when a small force is applied in the longitudinal direction, a large stress is generated in the transverse direction, which is then converted into an electrical signal.

[0092] Furthermore, due to their high sensitivity, fast response speed, good stability, and wide bandwidth, piezoelectric thin films are often used to measure dynamic or high-frequency signals. For example, the fast response speed of piezoelectric thin films allows for real-time measurement of changes in the measured physical quantity, making them highly suitable for applications requiring real-time monitoring. The high measurement accuracy of piezoelectric thin films, reaching millimeter or micrometer levels, facilitates the monitoring of partial discharge in individual battery cells.

[0093] It is also understood that, in this embodiment of the application, the ultrasonic sensor 102 may further include a charge conversion circuit for converting the charge signal corresponding to the ultrasonic signal into a first voltage signal after obtaining the charge signal. The charge conversion circuit may be disposed on the electrode layer (e.g., the upper electrode sheet or the lower electrode sheet) of the ultrasonic sensor 102.

[0094] In one possible implementation, to prevent damage and contamination of the PVDF piezoelectric film during use, a protective film is added to the surface of the PVDF piezoelectric film. Furthermore, since the PVDF piezoelectric film is a polymer material and electrodes cannot be directly welded, electrodes are led out from the PVDF piezoelectric film using a riveting method. When the ultrasonic signal propagates within the single cell, it causes minute deformations on the surface of the single cell, generating mechanical stress on the PVDF piezoelectric film attached to the surface of the single cell 101. This stress is converted into a charge signal, which, after passing through a charge conversion circuit, yields a first voltage signal. This first voltage signal is then transmitted to a signal acquisition component for signal processing.

[0095] Furthermore, in this embodiment, the signal acquisition component 103 and the ultrasonic sensor 102 are separate structures and are not integrated into a single component; or, in other words, the signal acquisition component 103 and the ultrasonic sensor 102 are independently configured and housed in different components. For example, the ultrasonic sensor 102 and the single battery cell 101 can be housed in the battery module or electrical box that carries the single battery cell 101. However, considering the size and layout of the battery module or electrical box, the signal acquisition component 103 and / or the detection component 104 can be housed in a component outside the battery module or electrical box.

[0096] Thus, by placing the ultrasonic sensor 102 in the battery box, the signal attenuation caused by partial discharge is small because the ultrasonic sensor 102 is relatively close to the individual battery cells. At the same time, by placing the signal acquisition component 103 and the detection component 104 in components outside the battery module or battery box, the size of the battery module or battery box can be reduced, thereby reducing costs.

[0097] In one possible implementation, the signal acquisition component 103 can be integrated into the Cell Supervision Circuit (CSC), or in other words, the signal acquisition component 103 can be integrated with the CSC component. For the CSC component, the internal signal acquisition component 103 can be connected to the ultrasonic sensor 102 via a first acquisition line to acquire the first voltage signal generated by partial discharge. In addition, the CSC component can also be connected to the individual battery cell 101 via a second acquisition line for sampling and processing of voltage, current, temperature, etc., of the individual battery cell 101.

[0098] In one possible implementation, the detection component 104 can be integrated into a Slave Battery Management Unit (SBMU) or a Battery Management System (BMS). That is, the detection component 104 can be integrated with the SBMU or the BMS. For the SBMU or BMS, in addition to partial discharge identification via the detection component 104, it can also perform other battery state monitoring, such as sampling battery current, total battery voltage, and ambient temperature for individual cells, estimating remaining charge (SOC), and performing insulation detection.

[0099] In other words, in this embodiment, the signal acquisition component 103 and the ultrasonic sensor 102 are set separately, and the signal acquisition component 103 can be integrated with the existing battery detection device, and the detection component 104 can be integrated with the cluster-level battery management unit or the battery management system, thereby solving the problem of component space occupation, allowing the ultrasonic sensor to be placed inside the battery device, and the signal acquisition component and the detection component can reuse the existing control board without occupying additional space, and can make reasonable use of resources, thereby reducing costs.

[0100] In this case, the signal detected by the ultrasonic sensor 102 can be transmitted to the CSC component first, and then aggregated to the SBMU or BMS component. In this way, since the ultrasonic sensor 102 is disposed on the insulating layer on the surface of the single cell, the distance between the ultrasonic sensor 102 and the single cell 101 is small. Based on the piezoelectric effect of the ultrasonic sensor, the signal attenuation caused by partial discharge is small. Moreover, the piezoelectric film has the characteristics of high sensitivity, fast response speed and good stability, which is conducive to the monitoring of partial discharge of the single cell. The signal acquisition component 103 and the ultrasonic sensor 102 are set separately, which not only solves the problem of component space occupation, but also detects the partial discharge signal of the single cell inside the battery device without increasing the size of the battery device. Moreover, the signal acquisition component 103 processes the first voltage signal. At this time, the processed first voltage signal has undergone signal amplification, acquisition and filtering, which can also improve the anti-interference ability during signal transmission and improve the signal-to-noise ratio. Then, the detection component 104 performs calculation processing on the processed first voltage signal, thereby enabling the monitoring of partial discharge of the single cell. This not only realizes online monitoring of partial discharge of the single cell, but also the ultrasonic sensor has a faster response speed than insulation resistance monitoring, which can prevent insulation failure inside the single cell more timely, and thus can provide real-time warning of whether the battery insulation status has deteriorated.

[0101] It is also understood that, in this embodiment of the application, for the single cell 101, the surface of the single cell 101 has a blue film (referred to as "blue film"), which is also called a separator film, anti-stick film, etc. It is the insulating layer described in the foregoing embodiments. As a protective film on the surface of the single cell, the mainstream material is polyethylene terephthalate (PET) film. As an insulating material between cells, it can play a good protective role and prevent the single cell from adversely affecting other single cell components due to various faults. Among them, the ultrasonic sensor 102 can be attached to the outer surface of the blue film of the single cell 101.

[0102] In other embodiments, the insulating layer may also include an adhesive layer, such as a polymer adhesive layer, on the surface of the individual battery cell.

[0103] In addition, in this embodiment, the ultrasonic sensor 102 should be disposed at a suitable location on the individual battery 101 so that the captured partial discharge signal can effectively reflect the insulation failure process of the battery. In some embodiments, the placement location of the ultrasonic sensor 102 on the individual battery 101 may include at least one of the following locations: the top of the individual battery 101, the bottom of the individual battery 101, the side of the individual battery 101, etc.; but it is not limited to these. Among them, the bottom (or "below") of the individual battery 101 may be, for example, located below the bottom R-corner region of the individual battery 101, or it may be located below the bottom planar region of the individual battery 101, etc.

[0104] In one possible implementation, the ultrasonic sensor 102 may be disposed below the bottom R-corner region of the single cell 101, and / or below the bottom planar region of the single cell 101.

[0105] Here, the R-angle region typically refers to the four corners at the bottom of the battery. The R-angle is a crucial parameter in lithium batteries, relating to the angle between the migration paths of lithium ions in the positive and negative electrode materials and those in the electrolyte. This angle is essential for describing the battery's internal structure and ion migration characteristics. The size of the R-angle determines the directness of the ion migration path, thus affecting the battery's internal resistance and performance. Specifically, a smaller R-angle indicates a more direct lithium ion migration path, lower internal resistance, and better performance. Therefore, in this embodiment, placing the ultrasonic sensor 102 below the bottom R-angle region of the single-cell battery 101 is more effective than placing it below the bottom planar region of the single-cell battery 101.

[0106] It should also be noted that, in this embodiment, since the vibration process of partial discharge can be transmitted, but the signal attenuation is significant, if the ultrasonic sensor 102 is placed at the bottom of the single cell 101, the distance between the ultrasonic sensor and the single cell is small. Due to the piezoelectric effect of the ultrasonic sensor 102, the signal attenuation caused by partial discharge is small. Furthermore, considering that the vibration direction is vertical, it is not recommended to place the ultrasonic sensor 102 on the side of the single cell, as the vibration direction is parallel to the placement direction of the piezoelectric film, making it impossible to accurately detect the vibration. It is also not recommended to place the ultrasonic sensor 102 on the top of the single cell, as the signal attenuation caused by partial discharge is large. In practical applications, it is generally recommended to place the ultrasonic sensor 102 below the bottom of the single cell 101 (e.g., below the bottom planar area and / or below the bottom R-corner area). In this case, the pressure generated by the partial discharge vibration is transmitted to the piezoelectric film structure, making it easier for the piezoelectric film structure to sense deformation and thus easier to detect vibration. This makes the measurement by the ultrasonic sensor 102 more accurate. Moreover, based on the characteristics of high sensitivity, fast response speed, and good stability of the piezoelectric film, it is beneficial for realizing the monitoring of partial discharge in single cells.

[0107] For example, Figure 2 This is a schematic diagram illustrating an application scenario for the attachment position of an ultrasonic sensor, as provided in an embodiment of this application. Figure 2 As shown, the ultrasonic sensor 102 uses a piezoelectric film as an example. A polyurethane (PU) adhesive 105 exists between the individual battery 101 and the metal base plate 106 to fix the bottom of the individual battery 101 to the metal base plate 106. The ultrasonic sensor 102 can be placed below the bottom of the individual battery 101. For example, the ultrasonic sensor 102 can be placed between the outer surface of the piezoelectric film of the individual battery 101 and the PU adhesive 105, or it can be placed between the PU adhesive 105 and the metal base plate 106.

[0108] In some embodiments, the number of individual battery cells 101 inside the battery device 10 can be one or more. When there are multiple individual battery cells 101, the multiple individual battery cells 101 are connected in series to form a battery module. In some embodiments, the ultrasonic sensor 102 is disposed in at least one of the following locations inside the battery module:

[0109] Below the bottom R-corner area of ​​the battery in the preset position inside the battery module;

[0110] Below the bottom plane area of ​​the battery in a preset position inside the battery module;

[0111] Below the bottom R-corner area of ​​the battery in a non-preset position inside the battery module;

[0112] Below the bottom plane area of ​​the battery in a non-preset position inside the battery module.

[0113] In this embodiment, the preset position battery may include: a first-end single cell and / or a last-end single cell. Furthermore, the preset position battery may also be a single cell located at a specific position within the battery module; no limitation is made here.

[0114] It should also be noted that, in this embodiment, the battery module can be placed inside an electrical box. Thus, based on common energy storage box and cell structures, the ultrasonic sensor 102 can be positioned in a suitable location, including but not limited to the following locations:

[0115] Location 1: Below the bottom R-corner area of ​​the first and last individual cells inside the battery module, the ultrasonic sensor 102 is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box.

[0116] Location 2: Below the bottom plane area of ​​the first and last individual cells inside the battery module, the ultrasonic sensor 102 is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box.

[0117] Location 3: Below the bottom R-corner area of ​​the non-first and last single cell inside the battery module, the ultrasonic sensor 102 is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box.

[0118] Location 4: Below the bottom plane area of ​​the non-first and last single cell inside the battery module, the ultrasonic sensor 102 is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box.

[0119] Location 5: The ultrasonic sensor 102 is attached to the inner side or outer surface of the battery module end plate;

[0120] Location 6: The ultrasonic sensor 102 inside the same battery module is attached to the surface of the heat insulation pad between the large surfaces of two adjacent single cells, or embedded in the heat insulation pad.

[0121] Here, the battery module end plate is positioned opposite the large surface of the individual battery cells. This end plate is a key component connecting the individual battery cells, and its main function is to provide electrical connection and mechanical fixation within the battery module. The ultrasonic sensor 102 can be positioned above the top of the individual battery cell, below the bottom of the individual battery cell, or between two adjacent individual batteries. Alternatively, it can be positioned inside or on the outer surface of the battery module end plate. Specifically, when the ultrasonic sensor 102 is positioned above the top of the individual battery cell, it can be attached to the outer surface of the blue film on the top of the individual battery cell, or it can be attached to the upper or lower surfaces of the top plate of the battery box. In this case, the ultrasonic sensor 102 is positioned above the top of the individual battery cell. Similarly, when the ultrasonic sensor 102 is positioned below the bottom of the individual battery cell, it can be attached to the outer surface of the blue film on the bottom of the individual battery cell (e.g., the outer surface of the blue film in the bottom R-corner area or the bottom flat area), or it can be attached to the upper or lower surfaces of the bottom plate of the battery box. In this case, the ultrasonic sensor 102 is positioned below the bottom of the individual battery cell. No limitations are imposed here.

[0122] It should also be noted that, in this embodiment, the placement of the ultrasonic sensor 102 can be directly related to the battery insulation failure mode, and the captured signal can accurately and effectively reflect the insulation failure process. Of the six positions provided above, positions 5 and 6 are the least effective, considering the vibration process and direction of partial discharge. That is, in this embodiment, considering that the vibration process of partial discharge can be transmitted and that the vibration direction is up and down, to avoid significant signal attenuation, the ultrasonic sensor 102 is typically placed at the bottom of the individual battery cell inside the battery module. In this case, the pressure generated by the partial discharge vibration is transmitted to the ultrasonic sensor 102, making it easier for the ultrasonic sensor 102 to sense deformation and thus more easily detect vibration, resulting in more accurate measurements. Furthermore, based on the high sensitivity, fast response speed, and good stability of the piezoelectric film, this facilitates the monitoring of partial discharge in individual batteries.

[0123] It should also be noted that, in this embodiment, the number of ultrasonic sensors 102 placed inside the battery module can be one or more. Ideally, the ultrasonic sensor 102 can be placed at the bottom of each individual cell. Considering cost factors, the ultrasonic sensor 102 can also be placed only at the bottom of the first and last individual cells, because these two individual cells include both cases of lowest and highest battery voltage, i.e., the placement position of the ultrasonic sensor 102 is generally recommended to be position 1 and position 2. In addition, considering that the R-corner region is crucial for describing the internal structure and ion migration characteristics of the battery, based on a comprehensive consideration of cost and monitoring effect, this embodiment can choose (position 1): below the bottom R-corner region of the first and last individual cells inside the battery module, the ultrasonic sensor 102 is attached to the outer surface of their respective blue film.

[0124] For example, taking the ultrasonic sensor 102 as a piezoelectric thin film sensor, the size of the piezoelectric thin film sensor can be 25mm × 13mm × 28μm. Furthermore, there are many types of parameter values ​​for piezoelectric thin film sensors; Table 1 provides an illustrative range of performance parameters for a piezoelectric thin film sensor.

[0125] Table 1

[0126] Performance parameters unit numerical values thickness μm 25～100 Highest frequency band MHz 100 piezoelectric constant (d33) pC / N >15 capacitance nF <0.3 elastic modulus <![CDATA[N / m 2 ]]> <![CDATA[>2×10 9 <!-- 11 -->]]> Bending resistance Second-rate No less than 1 million Maximum operating temperature ℃ >60 (BMS alarm threshold) Maximum working field strength kV / mm ≥40 (≥0.5 times the field strength of blue film initiation)

[0127] It is also understood that, in the embodiments of this application, for the piezoelectric thin film sensor, the piezoelectric thin film has no polarization direction in its initial state, and polarization only occurs under specific conditions. After applying pressure or an electric field, the positive and negative charges in the piezoelectric material will rearrange, resulting in different polarities at the top and bottom ends of the material. This process is called material polarization.

[0128] In this embodiment, the piezoelectric thin-film sensor may include a piezoelectric material layer and an electrode layer stacked in a stacked manner. The electrode layer includes an upper electrode sheet and a lower electrode sheet, which are respectively disposed on the upper and lower surfaces of the piezoelectric material layer. In one possible implementation, assuming that the piezoelectric material layer is subjected to downward pressure, then according to the piezoelectric effect, the positive and negative charges inside the electrode layer will redistribute, with positive charges concentrating upward and negative charges concentrating downward, thereby forming an upward polarization direction. In the application of the piezoelectric thin-film sensor, when external pressure or tension is applied, the polarization direction of the electrode layer will change accordingly, thereby generating a charge output signal for monitoring the partial discharge of a single battery cell.

[0129] For example, Figure 3 This is a schematic diagram illustrating an application scenario of a piezoelectric thin-film sensor provided in an embodiment of this application. For example... Figure 3As shown, the piezoelectric thin-film sensor may include a lower electrode 302, a piezoelectric material layer 301, and an upper electrode 303 stacked together, with a signal line 304 led out from the upper electrode 303. When partial discharge occurs inside the single cell 101, an ultrasonic signal 305 is generated, causing the piezoelectric material layer 301 to deform. This causes a corresponding change in the polarization direction of the lower electrode 302 and the upper electrode 303. The generated charge is then converted into a first voltage signal and led out via the signal line 304 for transmission to the signal acquisition component 103.

[0130] It is also understood that, in the embodiments of this application, the signal acquisition component 103 can be coupled to the ultrasonic sensor 102 through a signal shielding channel.

[0131] The signal shielding channel can be a wired channel or a wireless channel. For example, a wired channel can include metal lines on a flexible substrate, with the metal lines covering a shielding layer; or it can utilize a data acquisition line, with shielding elements disposed around the data acquisition line.

[0132] In this embodiment, since the signal detected by the ultrasonic sensor is very weak (e.g., on the order of millivolts), it is easily interfered with. In this case, the signal acquisition component and the ultrasonic sensor are coupled through a signal shielding channel, thereby enabling signal shielded transmission and improving anti-interference capability.

[0133] In one possible implementation, the ultrasonic sensor 102 can be coupled to the signal acquisition component 103 via a first acquisition line. Figure 1 Based on the battery device 10 shown, see... Figure 4 The battery device 10 may also include a shielding element 107, and the shielding element 107 is located around the first acquisition line.

[0134] It should be noted that, due to the capacitive nature of piezoelectric thin-film sensors, their resistance to electromagnetic interference is weak, and can be disregarded when the output signal is very high or the data accuracy requirements are not high. However, in this embodiment, because the signal detected by the ultrasonic sensor 102 is very weak (e.g., on the order of millivolts), it is easily affected by interference, so measures need to be taken to shield against electromagnetic interference. The measure taken here is to add a shielding element 107. In addition, a coaxial cable can also be used for the first acquisition line, thereby achieving shielded signal transmission and improving the anti-interference capability.

[0135] It should also be noted that, in this embodiment, considering the extremely small thickness and high flexibility of the piezoelectric thin film sensor, and the thin surface electrodes, conventional welding methods are not suitable for the piezoelectric thin film. In this embodiment, to prevent problems with the piezoelectric thin film sensor due to the influence of the lead wire connections, the signal lines of the piezoelectric thin film sensor are led out in the same direction and on the same plane. This facilitates the connection between the signal lines and the first acquisition line, thereby ensuring that the signal enters the signal acquisition component 103 with minimal interference. The connection method can be either crimping with crimp terminals or riveting with hollow rivets, but no limitation is imposed.

[0136] In some embodiments, see Figure 5 The signal acquisition component 103 may include a signal amplification circuit 501 and an acquisition filter circuit 502, wherein:

[0137] The signal amplification circuit 501 may include a first filter circuit 5011, a first operational amplifier circuit 5012, and a second operational amplifier circuit 5013. The input terminal of the first filter circuit 5011 is coupled to the ultrasonic sensor 102, and the output terminal of the first filter circuit 5011 is connected to the first operational amplifier circuit 5012. The first operational amplifier circuit 5012 and the second operational amplifier circuit 5013 are cascaded to amplify and filter the first voltage signal and output a second voltage signal.

[0138] The acquisition and filtering circuit 502 may include a signal acquisition circuit 5021 and a second filtering circuit 5022. The signal acquisition circuit 5021 is connected between the output terminal of the second operational amplifier circuit 5013 and the input terminal of the second filtering circuit 5022, and is used to acquire and filter the second voltage signal and output the processed first voltage signal.

[0139] In one possible implementation, for the signal amplifier circuit 501, see [link to relevant documentation]. Figure 6The first filter circuit 5011 may include a fifth resistor R5 and a first capacitor C1. The first operational amplifier circuit 5012 may include a first operational amplifier element U1, a first resistor R1, a third resistor R3, a sixth resistor R6, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4. The second operational amplifier circuit 5013 may include a second operational amplifier element U2, a second resistor R2, a seventh resistor R7, an eighth resistor R8, and a fifth capacitor C5. The power supply VCC is connected to the positive input terminal of the first operational amplifier element U1 through the first resistor R1. The first filter circuit 5011 is connected to the negative input terminal of the first operational amplifier element U1. The output terminal of the first operational amplifier element U1 is connected to the positive input terminal of the second operational amplifier element U2. Furthermore, the power supply VCC also supplies power to the first and second operational amplifier elements U1 and U2. The third capacitor C3 has a filtering function, making the voltage of the power supply VCC smoother and more stable. For details on the connections between the components, please refer to [link to details]. Figure 6 .

[0140] In this embodiment, the fifth resistor R5 is connected in series with the first capacitor C1, which can filter the low-frequency signal in the first voltage signal, retaining only the high-frequency signal. Specifically, the cutoff frequency can be designed by properly selecting the RC parameters, thereby filtering out the low-frequency signal.

[0141] In this embodiment, the first operational amplifier circuit 5012 and the second operational amplifier circuit 5013 are cascaded to achieve a two-stage amplifier circuit design for better signal amplification. The selection of operational amplifier components is flexible; both the first operational amplifier component U1 and the second operational amplifier component U2 can be selected based on cost, such as LF412, TL072, or LF356. For the second operational amplifier circuit 5013, the amplification factor can be adjusted from 1 to 100 times using the adjustable resistor R2.

[0142] In one possible implementation, for Figure 6 The component parameters are as follows: the resistance of the fifth resistor R5 can be set to 5kΩ, the capacitance of the first capacitor C1 can be set to 0.01uF, the resistance of the first resistor R1 can be set to 100kΩ, the resistance of the third resistor R3 can be set to 100kΩ, the resistance of the sixth resistor R6 can be set to 10MΩ, the capacitance of the second capacitor C2 can be set to 1uF, the capacitance of the third capacitor C3 can be set to 1uF, the capacitance of the fourth capacitor C4 can be set to 100pF, the resistance of the second resistor R2 can be set to 100kΩ and is adjustable, the resistance of the seventh resistor R7 can be set to 1kΩ, the resistance of the eighth resistor R8 can be set to 100kΩ, and the capacitance of the fifth capacitor C5 can be set to 0.01uF, but no specific limitation is made.

[0143] In another possible implementation, for the acquisition and filtering circuit 502, the signal acquisition circuit 5021 should select a synchronous signal acquisition card with high sampling rate, low resolution and short response time, such as PXI-8512B, etc. After converting the continuous analog voltage signal into a discrete digital signal using analog-to-digital conversion, it is sent to the second filtering circuit 5022 for processing to filter out high-frequency noise signals.

[0144] In some embodiments, the signal acquisition circuit 5021 employs a data acquisition element with a sampling rate of not less than 10 megahertz per second (MS / s). Exemplarily, the data acquisition element can be a high-sampling-rate synchronous signal acquisition card, such as the PXI-8512B.

[0145] Thus, in this embodiment of the application, according to the Nyquist theorem, based on the actual tested partial discharge frequency band of the battery cell, the signal sampling rate is generally required to be no less than 10 megahertz per second, thereby meeting the sampling requirements of the partial discharge frequency band of the battery cell.

[0146] In other words, in this embodiment, the signal amplification circuit 501 can amplify and filter the first voltage signal. The signal filtering can remove low-frequency signals in the first voltage signal. Moreover, the signal amplification adopts a two-stage amplification circuit design, which can better achieve the preset amplification and enhancement of the signal, amplify the signal from the smallest receivable range to the perceptible range, and increase the signal strength, thereby ensuring the stability and reliability of the signal and reducing the probability of signal interference. Then, the acquisition and filtering circuit 502 performs signal acquisition and filtering. It can first use analog-to-digital conversion to convert the continuous analog signal into a discrete digital signal, and then use signal filtering to remove high-frequency noise signals in the first voltage signal. This not only meets the sampling requirements of the cell partial discharge frequency band, but also obtains a voltage signal for partial discharge identification (i.e., the processed first voltage signal), which is beneficial for realizing the partial discharge monitoring of individual cells.

[0147] It is also understood that, in the embodiments of this application, after the detection component 104 receives the processed first voltage signal, it can perform calculation processing on the processed first voltage signal to obtain the monitoring result characterizing the partial discharge of the single cell 101.

[0148] In one possible implementation, the detection component 104 can perform partial discharge identification based on time-domain features. In some embodiments, the detection component 104 can be used to extract time-domain features from the processed first voltage signal to obtain first time-domain features; match the first time-domain features with a preset time-domain feature library to obtain a monitoring result characterizing the partial discharge of a single cell; wherein, the preset time-domain feature library is used to store the correspondence between different time-domain features and monitoring results.

[0149] In this embodiment, the time-domain features may include, but are not limited to, the peak signal repetition rate (times / minute) and the average signal amplitude corresponding to the partial discharge allowable level threshold. Furthermore, the preset time-domain feature library may be constructed based on experimental results and simulation calculations from a large number of partial discharge tests.

[0150] In this way, after obtaining the processed first voltage signal (i.e., the "time domain signal"), the first time domain feature can be obtained by extracting the time domain feature from the processed first voltage signal; the extracted first time domain feature is matched with the preset time domain feature library to obtain the monitoring result characterizing the partial discharge of a single cell. Thus, based on the extracted time domain feature, it can be determined whether the partial discharge exceeds the standard, thereby realizing the monitoring of partial discharge of a single cell.

[0151] In another possible implementation, the detection component 104 can perform partial discharge identification based on frequency domain features. In some embodiments, the detection component 104 can be used to perform a Fourier transform on the processed first voltage signal to determine the spectrum of the processed first voltage signal; extract frequency domain features based on the spectrum of the processed first voltage signal to obtain a first frequency domain feature; and match the first frequency domain feature with a preset frequency domain feature library to obtain a monitoring result characterizing the partial discharge of a single cell; wherein the preset frequency domain feature library is used to store the correspondence between different frequency domain features and monitoring results.

[0152] In this embodiment, the frequency domain features may include, but are not limited to: maximum spectral amplitude (or "characteristic frequency band peak"), mean square frequency (MSF), centroid frequency (FC), spectral variance (VF), and root variance frequency (RVF). Furthermore, the preset frequency domain feature library may also be constructed based on experimental results and simulation calculations from a large number of partial discharge tests, used to characterize the correspondence between different frequency domain features and monitoring results.

[0153] In this way, after obtaining the processed first voltage signal (i.e., the "time domain signal"), the processed first voltage signal can be transformed into the frequency domain by performing frequency domain transformation, such as wavelet transform, Fourier transform (FT), or Fast Fourier transform (FFT), so as to extract spectral components, such as the first frequency domain feature. The extracted first frequency domain feature is then matched with a preset frequency domain feature library to obtain the monitoring result characterizing the partial discharge of a single battery cell. Based on the extracted frequency domain features, it can be determined whether the partial discharge exceeds the standard, thus realizing the monitoring of partial discharge of a single battery cell.

[0154] In some embodiments, Figure 1 Based on the battery device 10 shown, see... Figure 7 The battery device 10 may also include an alarm component 108, wherein:

[0155] The alarm component 108 is connected to the detection component 104 and is used to generate alarm information based on the monitoring results. The alarm information is used to indicate the degree of partial discharge of the single cell 101.

[0156] In this embodiment of the application, after obtaining the monitoring results of the partial discharge of a single cell, the alarm component 108 can generate alarm information based on the monitoring results. The alarm information is used to indicate the degree of partial discharge of the single cell 101.

[0157] In this embodiment of the application, the alarm information can be divided into a first alarm information, a second alarm information, and a third alarm information according to the degree of partial discharge of the single cell 101. These alarm information are used to indicate different degrees of partial discharge in the single cell. For example, the first alarm information indicates mild partial discharge, the second alarm information indicates moderate partial discharge, and the third alarm information indicates severe partial discharge (i.e., a serious fault occurs).

[0158] In this embodiment, the alarm component 108 may include a voice announcer, indicator lights, etc., and is also used to issue alarm information to management personnel. For example, taking an indicator light as an example, if the indicator light is yellow, it indicates that the individual battery 101 has experienced mild partial discharge, at which point the insulation resistance needs to be checked; if the indicator light is orange, it indicates that the individual battery 101 has experienced moderate partial discharge, at which point partial discharge continues; if it does not decrease after 30 minutes, a request is made to disconnect the fault point; if the indicator light is red, it indicates that the individual battery 101 has experienced a serious fault, at which point the insulation has failed, and the fault point should be disconnected immediately. In addition, if the indicator light is green, or the indicator light is off, it indicates that the individual battery 101 does not have partial discharge, at which point the insulation is normal.

[0159] In other words, in this embodiment of the application, after obtaining the monitoring results characterizing the partial discharge of the single cell 101, the alarm component 108 can be used to generate corresponding alarm information. The alarm information can indicate the degree of partial discharge of the single cell 101 and can also notify the management personnel to repair the fault caused by the partial discharge in time, thereby preventing insulation failure in a timely manner.

[0160] For example, Figure 8 This is a schematic diagram illustrating an application scenario of a battery device provided in an embodiment of this application. For example... Figure 8 As shown, this includes an SBMU component 803, two electrical boxes, and corresponding CSC components for each of the two electrical boxes. The two electrical boxes may include a first electrical box 801-1 and a second electrical box 801-2, and the two CSC components may include a first CSC component 802-1 and a second CSC component 802-2. The first electrical box 801-1 includes a first battery module B1, and ultrasonic sensors 1 are respectively arranged on the outer surface of the blue film in the bottom R-corner region of the first and last individual battery cells inside the first battery module B1. The second electrical box 801-2 includes a second battery module B2, and ultrasonic sensors 2 are respectively arranged on the outer surface of the blue film in the bottom R-corner region of the first and last individual battery cells inside the second battery module B2. The first CSC component 802-1 includes a first signal acquisition component 103-1 and a first communication module D1. The first signal acquisition component 103-1 is coupled to an ultrasonic sensor 1 in the first electrical box 801-1. The ultrasonic sensor 1 converts the ultrasonic signal generated by the partial discharge of the first battery module B1 into a first voltage signal. Then, the first signal acquisition component 103-1 processes the first voltage signal and transmits it to the third communication module D3 in the SBMU component 803 via the communication link between the first communication module D1 and the third communication module D3. The second CSC component 802-2 includes a second signal acquisition component 103-2 and a second communication module D2. The second signal acquisition component 103-2 is coupled to an ultrasonic sensor 2 in the second electrical box 801-2. The ultrasonic sensor 2 converts the ultrasonic signal generated by the partial discharge of the second battery module B2 into a first voltage signal. Then, the second signal acquisition component 103-2 processes the first voltage signal and transmits it to the third communication module D3 in the SBMU component 803 via the communication link between the first communication module D1 and the third communication module D3. Finally, in SBMU component 803, the third communication module D3 outputs the processed first voltage signal to the detection component 104 for processing the processed first voltage signal to obtain the monitoring result characterizing the partial discharge of a single cell.

[0161] In other words, in this embodiment, the ultrasonic sensor can be installed in each battery compartment containing the individual cells, the signal acquisition component is installed in the CSC component, and the detection component is installed in the SBMU component. The signal detected by the ultrasonic sensor is first input to the CSC component and then aggregated in the SBMU component. Finally, the detection component 104 performs time-domain feature extraction / frequency-domain feature extraction, and monitors whether partial discharge exceeds the limit based on the extracted features.

[0162] This application provides a battery device 10, in which an ultrasonic sensor is disposed on the insulating layer on the surface of a single battery cell. The small distance between the ultrasonic sensor and the single battery cell results in minimal signal attenuation caused by partial discharge, thus facilitating partial discharge monitoring of the single battery cell. The separate arrangement of the signal acquisition component and the ultrasonic sensor solves the space occupation problem, allowing the ultrasonic sensor to be placed inside the battery device. Furthermore, after converting the ultrasonic signal generated by partial discharge into a first voltage signal, and processing it through signal amplification, acquisition, and filtering, the processed first voltage signal has already undergone signal amplification, acquisition, and filtering, thereby improving the anti-interference capability during signal transmission and enhancing the signal-to-noise ratio. After the detection component processes the processed first voltage signal, the monitoring result determines whether the partial discharge of the single battery cell exceeds the standard. This not only achieves online monitoring of partial discharge in the single battery cell, but also, compared to insulation resistance monitoring, the ultrasonic sensor has a faster response speed, enabling more timely prevention of insulation failure within the single battery cell and providing real-time early warning of whether the battery insulation state has deteriorated.

[0163] In another embodiment of this application, Figure 9 A flowchart illustrating a partial discharge monitoring method provided in this application embodiment. Figure 1 .like Figure 9 As shown, the method includes:

[0164] S901, acquire the first voltage signal output by the ultrasonic sensor, wherein the first voltage signal is obtained by converting the ultrasonic signal generated by the partial discharge of a single cell by the ultrasonic sensor.

[0165] S902 uses the signal acquisition component to process the first voltage signal and output it to the detection component.

[0166] S903 uses a detection component to process the processed first voltage signal to obtain monitoring results characterizing the partial discharge of a single cell.

[0167] In this embodiment, the method can be applied to the battery device described in the foregoing embodiments to achieve online monitoring of partial discharge in a single battery cell. The battery device includes a single battery cell, an ultrasonic sensor, a signal acquisition component, and a detection component. The surface of the single battery cell is provided with an insulating layer, and the ultrasonic sensor is disposed on the side of the insulating layer away from the single battery cell. The signal acquisition component is separately disposed from and coupled to the ultrasonic sensor, and the detection component is coupled to the signal acquisition component.

[0168] In this embodiment, the signal acquisition component and the ultrasonic sensor are separate structures, not integrated into a single component; or, more specifically, the signal acquisition component and the ultrasonic sensor are independently configured, housed in different components. For example, the ultrasonic sensor and the individual battery can be housed in an electrical box housing the battery. Considering the size and layout of the electrical box, the signal acquisition component and the detection component can be located in a component outside the electrical box. For instance, the signal acquisition component can be housed in the CSC component, and the detection component can be housed in the SBMU component, or the detection component can also be housed in the BMS component. In this way, the signal detected by the ultrasonic sensor can first be transmitted to the CSC component and then aggregated to the SBMU component.

[0169] In other words, in this embodiment, since the ultrasonic sensor is disposed on the insulating layer on the surface of the individual battery, the distance between the ultrasonic sensor and the individual battery is small, resulting in less signal attenuation caused by partial discharge, which is beneficial for monitoring the partial discharge of the individual battery. The separate arrangement of the signal acquisition component and the ultrasonic sensor not only solves the problem of component space occupation, but also enables the detection of partial discharge signals of individual batteries inside the battery device without increasing the size of the battery device. Moreover, the signal acquisition component processes the first voltage signal, such as performing signal amplification, acquisition, and filtering, thereby improving the anti-interference capability during signal transmission and improving the signal-to-noise ratio. Then, based on the calculation and processing of the processed first voltage signal by the detection component, the monitoring result characterizing the partial discharge of the individual battery is obtained. Thus, not only is online monitoring of partial discharge of individual batteries realized, but the ultrasonic sensor also has a faster response speed than insulation resistance monitoring, which can prevent insulation failure inside the individual battery more promptly, and thus can provide real-time early warning of whether the battery insulation status has deteriorated.

[0170] In some embodiments, the processing of the processed first voltage signal using a detection component to obtain monitoring results characterizing the partial discharge of a single cell may include:

[0171] The first time-domain feature is obtained by extracting time-domain features from the processed first voltage signal;

[0172] The first time-domain feature is matched with a preset time-domain feature library to obtain the monitoring results characterizing the partial discharge of a single cell; wherein, the preset time-domain feature library is used to store the correspondence between different time-domain features and monitoring results.

[0173] In this embodiment, the time-domain features may include, but are not limited to, the peak signal repetition rate (times / minute) and the average signal amplitude corresponding to the partial discharge allowable level threshold. Furthermore, the preset time-domain feature library may be constructed based on experimental results and simulation calculations from a large number of partial discharge tests.

[0174] In this way, after obtaining the processed first voltage signal (i.e., the "time domain signal"), the first time domain feature can be obtained by extracting the time domain feature from the processed first voltage signal; the extracted first time domain feature is matched with the preset time domain feature library to obtain the monitoring result characterizing the partial discharge of a single cell. Thus, based on the extracted time domain feature, it can be determined whether the partial discharge exceeds the standard, thereby realizing the monitoring of partial discharge of a single cell.

[0175] In some embodiments, the processing of the processed first voltage signal using a detection component to obtain monitoring results characterizing the partial discharge of a single cell may include:

[0176] Perform a Fourier transform on the processed first voltage signal to determine the spectrum of the processed first voltage signal;

[0177] Frequency domain features are extracted based on the spectrum of the processed first voltage signal to obtain the first frequency domain features;

[0178] The first frequency domain feature is matched with a preset frequency domain feature library to obtain the monitoring results characterizing the partial discharge of a single cell; wherein, the preset frequency domain feature library is used to store the correspondence between different frequency domain features and monitoring results.

[0179] In this embodiment, the frequency domain features may include, but are not limited to: maximum spectral amplitude (or "characteristic frequency band peak"), mean square frequency, centroid frequency, spectral variance, and spectral standard deviation. Furthermore, the preset frequency domain feature library may be constructed based on experimental results and simulation calculations from numerous partial discharge tests, used to characterize the correspondence between different frequency domain features and monitoring results.

[0180] In this way, after obtaining the processed first voltage signal (i.e., the "time domain signal"), the time domain signal can be transformed into the frequency domain by performing frequency domain transformation on the processed first voltage signal, such as using wavelet transform, Fourier transform, fast Fourier transform, etc., so as to extract spectral components, such as the first frequency domain feature. The extracted first frequency domain feature is matched with a preset frequency domain feature library to obtain the monitoring result characterizing the partial discharge of a single cell. Thus, based on the extracted frequency domain features, it can be determined whether the partial discharge exceeds the standard, thereby realizing the monitoring of partial discharge of a single cell.

[0181] In some embodiments, when the first time-domain feature is the average amplitude of the signal, the method further includes:

[0182] When the average amplitude of the processed first voltage signal is less than the first threshold, the monitoring result indicates that there is no partial discharge in the individual battery cell.

[0183] When the average amplitude of the processed first voltage signal is greater than or equal to the first threshold, the monitoring results indicate that there is partial discharge in the individual battery cell.

[0184] In this embodiment, the first threshold is a criterion used to determine whether a single battery cell has partial discharge. For example, the first threshold can be set to 5V, but it can be adjusted adaptively according to actual conditions; no limitation is made here.

[0185] In other words, in this embodiment of the application, taking the first time-domain feature as the average amplitude of the signal as an example, the average amplitude of the processed first voltage signal, i.e., the "average amplitude of the voltage signal," can be represented by U. If the average amplitude of the signal is less than the first threshold, for example, U < 5V, it indicates that the insulation is normal, and the monitoring result indicates that there is no partial discharge in the single cell. If the average amplitude of the signal is greater than or equal to the first threshold, for example, U ≥ 5V, it indicates that the insulation is abnormal, and the monitoring result indicates that there is partial discharge in the single cell. At this time, an alarm message can be further reported to notify the management personnel to repair the fault caused by the partial discharge in a timely manner, thereby preventing insulation failure in a timely manner.

[0186] In some embodiments, when the monitoring results indicate that a single cell has partial discharge, the method may further include:

[0187] When the average amplitude of the processed first voltage signal is greater than or equal to the first threshold and less than the second threshold, the alarm component generates the first alarm information.

[0188] When the average amplitude of the processed first voltage signal is greater than or equal to the second threshold and less than the third threshold, the alarm component generates a second alarm message.

[0189] When the average amplitude of the processed first voltage signal is greater than or equal to the third threshold, the alarm component generates a third alarm message.

[0190] In the embodiments of this application, the first alarm information, the second alarm information, and the third alarm information can be used to indicate different degrees of partial discharge in a single battery cell. For example, the first alarm information indicates mild partial discharge, the second alarm information indicates moderate partial discharge, and the third alarm information indicates severe partial discharge (i.e., a serious fault).

[0191] In this embodiment, the second threshold and the third threshold are indicators used to measure the severity of partial discharge in a single battery cell. For example, the second threshold can be set to 10V and the third threshold can be set to 15V, but these can also be adjusted adaptively according to actual conditions; no limitations are imposed here.

[0192] In one possible implementation, based on extensive experimental and simulation experience, taking a first threshold of 5V, a second threshold of 10V, and a third threshold of 15V as an example... Figure 2 An example of a monitoring state where a single cell exhibits partial discharge is shown.

[0193] Table 2

[0194]

[0195] In this embodiment, the alarm component may include a voice announcer, indicator lights, etc., and is also used to issue alarm information to management personnel. For example, taking an indicator light: if the indicator light is yellow, it indicates that a single cell has experienced mild partial discharge, at which point the insulation resistance needs to be checked; if the indicator light is orange, it indicates that a single cell has experienced moderate partial discharge, at which point partial discharge continues; if it does not decrease after 30 minutes, a request is made to disconnect the fault point; if the indicator light is red, it indicates that a single cell has experienced a serious fault, at which point the insulation has failed, and the fault point should be disconnected immediately. In addition, if the indicator light is green, or the indicator light is off, it indicates that there is no partial discharge in the single cell, and the insulation is normal.

[0196] In other words, in this embodiment of the application, taking the average amplitude of the signal as the first time-domain feature as an example, after obtaining the average amplitude of the processed first voltage signal, the degree of partial discharge of a single battery cell can be further determined based on the range of the average amplitude. Specifically, if the average amplitude is in the first range, for example, 5V≤U<10V, a first alarm message is generated, indicating that the single battery cell has experienced mild partial discharge; if the average amplitude is in the second range, for example, 10V≤U<15V, a second alarm message is generated, indicating that the single battery cell has experienced moderate partial discharge; if the average amplitude is in the third range, for example, U≥15V, a third alarm message is generated, indicating that the single battery cell has experienced severe partial discharge, leading to insulation failure, and the fault point needs to be immediately disconnected. In this way, different alarm messages can indicate the different degrees of partial discharge of a single battery cell, and can also notify management personnel to repair the fault caused by partial discharge in a timely manner, thereby preventing insulation failure in a timely manner.

[0197] In another embodiment of this application, an apparatus and method for online monitoring of partial discharge in a battery are provided. The battery can be a lithium battery, lead-acid battery, or other energy storage battery. To achieve online monitoring of partial discharge in the energy storage battery and provide real-time early warning of whether insulation degradation has occurred, in this embodiment, a PVDF flexible patch-type piezoelectric sensor (i.e., the aforementioned "ultrasonic sensor") can be arranged at a suitable location on the energy storage battery to convert the ultrasonic signal generated by partial discharge into a voltage signal. This signal is then amplified and filtered before being sent to the detection component.

[0198] In one possible implementation, the detection component can use FFT transformation to obtain the spectrum of partial discharge, filter out low-frequency interference, and extract the spectrum information that is strongly correlated with the partial discharge characteristics of the insulating layer on the surface of the single cell (i.e., the aforementioned "first frequency domain feature"); based on the extracted first frequency domain feature, it can determine whether the partial discharge exceeds the standard and issue an alarm message, thereby preventing insulation failure in a timely manner.

[0199] In the embodiments of this application, Figure 10 A flowchart illustrating a partial discharge monitoring method provided in this application embodiment. Figure 2 .like Figure 10 As shown, the method may include:

[0200] S1001, the ultrasonic signal generated by partial discharge is converted into the first voltage signal.

[0201] S1002, the first voltage signal is transmitted in a shielded manner.

[0202] S1003 is a signal amplification circuit that performs signal amplification and filtering.

[0203] S1004 is a signal acquisition and filtering circuit that performs signal acquisition and filtering.

[0204] S1005 performs spectrum conversion and frequency domain feature extraction.

[0205] S1006, an alarm message is issued.

[0206] It should be noted that if the detection component is not set in the BMS component, alarm information can still be sent to the BMS component to prevent insulation failure in a timely manner.

[0207] It should also be noted that, taking piezoelectric thin-film sensors as an example, they can be placed in suitable locations. Based on common energy storage box and cell structures, these locations include, but are not limited to, the following:

[0208] Location 1: Below the bottom R-corner area of ​​the first and last individual cells inside the battery module, the piezoelectric film sensor is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box;

[0209] Location 2: Below the bottom plane area of ​​the first and last individual cells inside the battery module, the piezoelectric film sensor is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box;

[0210] Location 3: Below the bottom R-corner area of ​​the non-first and last single cell inside the battery module, the piezoelectric film sensor is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box;

[0211] Location 4: Below the bottom plane area of ​​the non-first and last individual cells inside the battery module, the piezoelectric film sensor is attached to the outer surface of the blue film, or to the upper and lower surfaces of the bottom plate of the battery box;

[0212] Location 5: The piezoelectric thin film sensor is attached to the inner side or outer surface of the battery module end plate;

[0213] Location 6: The piezoelectric thin film sensor inside the same battery module is attached to the surface of the heat insulation pad between the large surfaces of two adjacent individual cells, or embedded in the heat insulation pad.

[0214] It should also be noted that the parameter setting requirements for piezoelectric thin film sensors can be found in Table 1 above.

[0215] In one possible implementation, the specific structure of the signal amplification circuit is as described above. Figure 6 As shown in the diagram. Here, the signal amplification circuit can be designed as a two-stage amplifier. After converting the charge signal into a voltage signal, a high cutoff frequency design can be achieved by properly selecting the RC parameters. The subsequent stage can achieve an adjustable amplification factor of 1 to 100 times through the adjustability of the second resistor R2.

[0216] Furthermore, the selection of operational amplifier components is quite flexible, with options such as LF412, TL072, and LF356 available based on cost. Figure 6 The preamplifier section (i.e., the first op-amp circuit 5012) may include circuit elements that connect the input and output terminals of the first op-amp element. Figure 6 The post-amplification section (i.e., the second op-amp circuit 5013) may include circuit elements that connect the input and output terminals of the second op-amp element.

[0217] In one possible implementation, the signal acquisition circuit should use a synchronous signal acquisition card with a high sampling rate, low resolution, and short response time, such as the PXI-8512B. It should then use analog-to-digital conversion to convert the continuous analog signal into a discrete digital signal before sending it to the second filtering circuit for processing. For example, the second filtering circuit can also be located within the BMS component.

[0218] In this embodiment of the application, according to the Nyquist theorem, based on the actual tested partial discharge frequency band of the battery cell, the signal sampling rate is required to be no less than 10MS / s.

[0219] In one possible implementation, after extracting the time-domain signal, a Fast Fourier Transform (FFT) can be performed to further extract spectral components and determine whether partial discharge has occurred. The frequency-domain features here include, but are not limited to, the maximum amplitude of the spectrum, the centroid frequency, and the spectral variance. Alternatively, time-domain features can be extracted for identification, including, but not limited to, the peak signal repetition rate (times / minute) and the average signal amplitude corresponding to exceeding the permissible partial discharge level threshold.

[0220] For example, this embodiment can be executed according to the steps of the above technical solution. The process includes:

[0221] The dimensions of the selected piezoelectric thin film sensor are 25mm×13mm×28μm, and the performance parameters meet the relevant requirements listed in Table 1 above.

[0222] The piezoelectric thin film sensor can be positioned below the bottom R-corner area of ​​the first and last individual cells inside the battery module. Specifically, the piezoelectric thin film sensor is attached to the outer surface of the blue film of the individual cell.

[0223] use Figure 6 The signal amplification circuit shown adjusts the amplification factor according to the electromagnetic noise conditions at the site.

[0224] The voltage signal output by the piezoelectric thin film sensor is acquired in real time at a sampling frequency of 10MHz. Partial discharge is identified based on the time-domain features extracted from the time-domain signal to obtain monitoring results characterizing the partial discharge of a single cell. Alarm information can also be generated and issued.

[0225] In the embodiments of this application, after signal calibration and combined with a large amount of experimental and simulation calculation experience, the monitoring threshold for battery partial discharge as shown in Table 2 above can be formulated.

[0226] This application provides a partial discharge monitoring method. The specific implementation of the aforementioned embodiments has been described in detail through the above embodiments. It can be seen that, according to the technical solutions of the aforementioned embodiments, on the one hand, for online monitoring of partial discharge indicators, it can prevent insulation failure more timely than insulation resistance monitoring, and will not affect voltage fluctuations; on the other hand, compared with the RC charging and discharging process (second-level) of insulation resistance monitoring, the response speed of this technical solution is faster (millisecond-level); furthermore, the arrangement position of the piezoelectric thin film sensor is directly related to the insulation failure mode of the cell, and the captured signal can truly and effectively reflect the insulation failure process; moreover, combined with signal amplification, acquisition and filtering, the anti-interference ability in the signal transmission process can be improved, thereby improving the signal-to-noise ratio; thus, it not only solves the component space occupation problem, but also realizes online monitoring of partial discharge of individual cells. Moreover, the ultrasonic sensor has a faster response speed than insulation resistance monitoring, which can prevent insulation failure inside the individual cell more timely, and thus can provide real-time early warning of whether the battery insulation state has deteriorated.

[0227] In another embodiment of this application, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed, can implement the partial discharge monitoring method described in the foregoing embodiments.

[0228] This application also provides a computer program product, including a computer program or instructions, which, when executed, can implement the partial discharge monitoring method as described in the foregoing embodiments.

[0229] It should be noted that the embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware aspects. Moreover, this application can take the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage and optical storage) containing computer-usable program code.

[0230] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0231] It should also be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0232] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0233] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0234] The features disclosed in the several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0235] The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0236] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology 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 battery device, characterized by, The battery device comprises: a single battery, a surface of which is provided with an insulation layer; an ultrasonic sensor, which is arranged on a side of the insulation layer away from the single battery; a signal acquisition assembly, which is arranged separately from the ultrasonic sensor and coupled to the ultrasonic sensor; a detection assembly, which is coupled to the signal acquisition assembly; wherein the ultrasonic sensor is configured to convert an ultrasonic signal generated by local discharge of the single battery into a first voltage signal; the signal acquisition assembly is configured to output the first voltage signal after processing to the detection assembly, and the detection assembly is configured to perform operation processing on the processed first voltage signal to obtain a monitoring result representing the local discharge of the single battery.

2. The battery device according to claim 1, characterized by The ultrasonic sensor comprises a piezoelectric film structure, wherein the piezoelectric film structure comprises a lower electrode sheet, a piezoelectric material layer and an upper electrode sheet arranged in sequence.

3. The battery device of claim 2, wherein The piezoelectric film structure is a flexible structure.

4. The battery device of claim 1, wherein The ultrasonic sensor is arranged below a bottom R-angle region of the single battery and / or below a bottom planar region of the single battery.

5. The battery device of claim 4, wherein, The number of the single batteries is multiple, and the multiple single batteries are connected in series to form a battery module. The ultrasonic sensor is arranged at at least one of the following positions inside the battery module: below a bottom R-angle region of a battery at a preset position inside the battery module; below a bottom planar region of the battery at the preset position inside the battery module; below a bottom R-angle region of a battery at a non-pre-set position inside the battery module; below a bottom planar region of the battery at the non-pre-set position inside the battery module; wherein the battery at the preset position comprises a first single battery and / or a last single battery.

6. The battery device of claim 1, wherein The signal acquisition assembly is coupled to the ultrasonic sensor through a signal shielding channel.

7. The battery device of claim 6, wherein The ultrasonic sensor is coupled to the signal acquisition assembly through a first acquisition line; wherein: The battery device further comprises a shielding element, and the shielding element is located around the first acquisition line.

8. The battery device of claim 1, wherein The signal acquisition assembly comprises a signal amplification circuit and an acquisition filtering circuit, wherein: The signal amplification circuit comprises a first filtering circuit, a first operational amplifier circuit and a second operational amplifier circuit, and an input end of the first filtering circuit is coupled to the ultrasonic sensor, an output end of the first filtering circuit is connected to the first operational amplifier circuit, the first operational amplifier circuit is cascaded with the second operational amplifier circuit, and is configured to perform signal amplification and filtering processing on the first voltage signal to output a second voltage signal; The acquisition filtering circuit comprises a signal acquisition circuit and a second filtering circuit, and the signal acquisition circuit is connected between an output end of the second operational amplifier circuit and an input end of the second filtering circuit, and is configured to perform signal acquisition and filtering processing on the second voltage signal to output the processed first voltage signal.

9. The battery device of claim 8, wherein, The signal acquisition circuit adopts a data acquisition element with a sampling rate of no less than 10 million times per second.

10. The battery device according to any one of claims 1 to 9, characterized by, The battery device further comprises an alarm circuit, wherein: The alarm circuit is connected with the detection component, and is configured to generate alarm information according to the monitoring result, the alarm information being used to indicate the local discharge degree of the single battery.

11. The battery device according to any one of claims 1 to 9, characterized by, The signal collection component is integrated in a battery detection device, and / or the detection component is integrated in a cluster-level battery management unit or a battery management system.

12. A partial discharge monitoring method applied to the battery device according to any one of claims 1 to 11; characterized by, The method comprises: acquiring a first voltage signal output by an ultrasonic sensor, wherein the first voltage signal is converted from an ultrasonic signal generated by the ultrasonic sensor based on the local discharge of the single battery; processing the first voltage signal by using a signal collection component and outputting the processed first voltage signal to a detection component; performing operation processing on the processed first voltage signal by using the detection component to obtain a monitoring result representing the local discharge of the single battery.

13. The method of claim 12, wherein, The operation processing on the processed first voltage signal by using the detection component to obtain the monitoring result representing the local discharge of the single battery comprises: performing time-domain feature extraction on the processed first voltage signal to obtain a first time-domain feature; matching the first time-domain feature with a preset time-domain feature library to obtain the monitoring result representing the local discharge of the single battery, wherein the preset time-domain feature library is used to store a corresponding relationship between different time-domain features and monitoring results.

14. The method of claim 12, wherein, The operation processing on the processed first voltage signal by using the detection component to obtain the monitoring result representing the local discharge of the single battery comprises: performing Fourier transform on the processed first voltage signal to determine a frequency spectrum of the processed first voltage signal; performing frequency-domain feature extraction according to the frequency spectrum of the processed first voltage signal to obtain a first frequency-domain feature; matching the first frequency-domain feature with a preset frequency-domain feature library to obtain the monitoring result representing the local discharge of the single battery, wherein the preset frequency-domain feature library is used to store a corresponding relationship between different frequency-domain features and monitoring results.

15. The method of claim 13, wherein, When the first time-domain feature is a signal average amplitude, the method further comprises: when the signal average amplitude of the processed first voltage signal is less than a first threshold, the monitoring result indicates that the single battery does not have local discharge; when the signal average amplitude of the processed first voltage signal is greater than or equal to the first threshold, the monitoring result indicates that the single battery has local discharge.

16. The method of claim 15, wherein, When the monitoring result indicates that the single battery has local discharge, the method further comprises: when the signal average amplitude of the processed first voltage signal is greater than or equal to the first threshold and less than a second threshold, an alarm component generates first alarm information; when the signal average amplitude of the processed first voltage signal is greater than or equal to the second threshold and less than a third threshold, the alarm component generates second alarm information; when the signal average amplitude of the processed first voltage signal is greater than or equal to the third threshold, the alarm component generates third alarm information; wherein the first alarm information, the second alarm information and the third alarm information are used to indicate different degrees of local discharge of the single battery.

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