Battery cell and battery pack capable of being tested in situ, system, and battery monitoring method

Abstract

The present invention relates to the technical field of battery safety. Disclosed are a battery cell and battery pack capable of being tested in situ, a system, and a battery monitoring method. The battery cell comprises a protective casing and an internal assembly provided inside the protective casing. The internal assembly comprises a battery winding pin, an ultrasonic sensor module adhered to the surface of the battery winding pin in a winding mode, and a battery winding tape layer adhered to the surface of the ultrasonic sensor module in a winding mode, wherein the ultrasonic sensor module is used for transmitting an ultrasonic transmission signal, receiving an ultrasonic reflection echo to perform ultrasonic testing, and performing real-time in-situ testing on the battery cell by means of the ultrasonic testing. On the basis of the technical solution provided by the present application, the ultrasonic sensor module inside the battery cell is used for performing the ultrasonic testing technology, so that real-time in-situ testing can be performed on the battery cell in service, thereby avoiding the risk caused by self-explosion of a battery.

Description

In-situ detectable battery cell, battery pack, system and battery monitoring method Technical Field

[0001] The present invention relates to the field of battery safety technology, and in particular to a battery cell, a battery pack, a system and a battery monitoring method capable of in-situ detection. Background Art

[0002] Power batteries are widely used components, particularly in new energy vehicles and large-scale energy storage, where they have become a core component. As power battery applications become more widespread, their safety has also drawn considerable attention.

[0003] Power batteries are prone to spontaneous combustion, a major factor affecting their safety. Spontaneous combustion is generally caused by a diaphragm breakdown, resulting in a short circuit in the battery, which generates a large amount of heat in a short period of time and causes combustion. While improving battery safety design standards can reduce the probability of spontaneous combustion, it remains difficult to fundamentally prevent it.

[0004] Therefore, there is an urgent need to provide a technical solution that can monitor the working status of the power battery in real time and improve the safety of the power battery.

[0005] Summary of the Invention

[0006] The object of the present invention is to provide a battery cell, a battery pack, a system and a battery monitoring method capable of in-situ detection, which can perform real-time in-situ detection on the battery cell.

[0007] In order to achieve the above-mentioned object of the invention, the present invention proposes the following technical solutions:

[0008] In one aspect, an in-situ detectable battery cell is provided, the battery cell comprising a protective shell and internal components disposed within the protective shell, the internal components comprising:

[0009] Battery winding needle;

[0010] An ultrasonic sensor module is adhered to the surface of the battery winding needle by winding;

[0011] A battery tape layer is adhered to the surface of the ultrasonic sensor module by winding;

[0012] The ultrasonic sensor module is used to transmit ultrasonic transmission signals and receive ultrasonic reflection echoes to perform ultrasonic detection, and to perform real-time in-situ detection of the battery cell through ultrasonic detection.

[0013] In a possible implementation, the ultrasonic sensor module includes a plurality of ultrasonic sensors, and the plurality of ultrasonic sensors form a multi-channel array structure.

[0014] In a possible implementation, the array structure includes: a linear array structure or a planar array structure.

[0015] In a possible implementation, the ultrasonic sensor module includes a single ultrasonic sensor.

[0016] In one possible implementation, the ultrasonic sensor includes the following layers connected sequentially from bottom to top:

[0017] A base layer, adapted to be attached to the surface of the battery winding needle and to support the piezoelectric material layer;

[0018] A piezoelectric material layer, configured to radiate the ultrasonic transmission signal outward and receive the ultrasonic reflection echo;

[0019] an acoustic matching layer, configured to reduce the acoustic impedance difference between the piezoelectric material and the battery tape layer;

[0020] The sealing layer is used to encapsulate and protect the ultrasonic sensor.

[0021] In a possible implementation, the thickness of the piezoelectric material layer is 1 um-1000 um, so that the frequency of the ultrasonic emission signal is designed to be 0.5 MHz-50 MHz.

[0022] In one possible implementation, a flexible circuit board connected to the ultrasonic sensor module is led out from one end of the battery winding needle, and a smart chip is mounted on the flexible circuit board. The smart chip is powered by the battery unit and is used as the driving and imaging unit of the ultrasonic sensor module.

[0023] In a possible implementation, the smart chip includes:

[0024] A front-end transceiver module is used to stimulate the ultrasonic sensor module to transmit the ultrasonic transmission signal, and to receive and process the ultrasonic reflection echo;

[0025] a beam control module, configured to perform delay control and form a grayscale matrix from the ultrasonic reflection echo;

[0026] an image processing module, configured to perform image processing according to the grayscale matrix to identify abnormal information in the battery cell;

[0027] A main control module, used for performing logical control on the smart chip;

[0028] A communication module, used to manage the communication interface of the smart chip;

[0029] Power management module, used for voltage management.

[0030] In a possible implementation, the winding configuration corresponding to the winding includes:

[0031] cylindrical;

[0032] or, cube;

[0033] Or, oval.

[0034] On the other hand, an in-situ detectable battery pack is provided, which includes a plurality of battery cells as described in the above aspects, and the smart chip of each battery cell is connected via a communication bus.

[0035] On the other hand, an early warning system is provided, which is connected to the battery pack as described in the above aspects. The early warning system supports prompting of risky battery cells in the battery pack. The risky battery cells are battery cells with abnormal information detected in real time in situ by ultrasonic detection.

[0036] In another aspect, a battery monitoring method is provided, which is applied to the battery cell according to the above aspect, and includes:

[0037] Transmitting an ultrasonic transmission signal through the ultrasonic sensor module to scan the interior of the battery cell;

[0038] receiving the ultrasonic reflection echo generated after scanning by the ultrasonic sensor module;

[0039] The ultrasonic sensor module transmits the ultrasonic reflected echo to the smart chip corresponding to the ultrasonic sensor module;

[0040] The intelligent chip analyzes the ultrasonic reflected echo to identify abnormal information in the battery cell.

[0041] In one possible implementation, the abnormal information includes:

[0042] the height of the abnormal point in the battery cell;

[0043] and / or, the location of the abnormal point in the battery cell.

[0044] In a possible implementation, the smart chip corresponds to a displacement address code;

[0045] The method further comprises:

[0046] The ultrasonic scanning identification result is reported by the smart chip, and the ultrasonic scanning identification result carries the displacement address code and the abnormal information in the battery unit.

[0047] In one possible implementation, the battery cell has a battery risk level;

[0048] The reporting of the ultrasonic scanning recognition result by the smart chip includes:

[0049] The ultrasonic scanning identification result is reported through the smart chip according to the information reporting frequency corresponding to the current battery risk level.

[0050] In one possible implementation, the battery risk level is determined based on at least one of the following information:

[0051] the current number of abnormal points in the battery cell;

[0052] the current size of the abnormal point in the battery cell;

[0053] a change trend of the number of abnormal points in the battery cell;

[0054] The size variation trend of the abnormal points in the battery cell.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] By winding the ultrasonic sensor on the surface of the battery winding needle and the battery tape layer on the surface of the ultrasonic sensor, the ultrasonic sensor module and the battery can be packaged and used together. Since ultrasound has the characteristics of non-destructive penetration detection, high resolution, low cost and long life, the ultrasonic sensor module inside the battery cell is used to perform ultrasonic detection technology, which can achieve real-time in-situ detection of battery cells in service and avoid the risk of battery self-explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] FIG1 is a schematic structural diagram of a battery unit provided in an embodiment of the present application;

[0058] FIG2 is a schematic structural diagram of a battery cell provided in an embodiment of the present application;

[0059] FIG3 is a schematic structural diagram of a battery unit provided in an embodiment of the present application;

[0060] FIG4 is a schematic structural diagram of a battery unit provided in an embodiment of the present application;

[0061] FIG5 is a schematic diagram of an ultrasonic reflection echo provided in an embodiment of the present application;

[0062] FIG6 is a schematic diagram of an ultrasonic reflection echo provided in an embodiment of the present application;

[0063] FIG7 is a schematic diagram of an ultrasonic reflection echo provided in an embodiment of the present application;

[0064] FIG8 is a schematic structural diagram of an ultrasonic sensor module with a linear array structure provided in an embodiment of the present application;

[0065] FIG9 is a schematic diagram of a winding of an ultrasonic sensor module of a linear array structure provided in an embodiment of the present application;

[0066] FIG10 is a schematic structural diagram of an ultrasonic sensor module with a planar array structure provided in an embodiment of the present application;

[0067] FIG11 is a schematic diagram of a winding ultrasonic sensor module of a planar array structure provided in an embodiment of the present application;

[0068] FIG12 is a schematic structural diagram of an ultrasonic sensor provided in an embodiment of the present application;

[0069] FIG13 is a schematic structural diagram of a battery unit provided in an embodiment of the present application;

[0070] FIG14 is a schematic diagram of signal propagation in a battery cell provided in an embodiment of the present application;

[0071] FIG15 is a schematic diagram of a battery unit connected to a smart chip provided in an embodiment of the present application;

[0072] FIG16 is a schematic diagram of a battery unit connected to a smart chip provided in an embodiment of the present application;

[0073] FIG17 is a schematic diagram of the structure of a smart chip provided in an embodiment of the present application;

[0074] FIG18 is a schematic structural diagram of a battery pack provided in an embodiment of the present application;

[0075] FIG19 is a schematic diagram of an early warning system connected to a battery unit provided in an embodiment of the present application;

[0076] FIG20 is a schematic diagram of a warning system for displaying prompts provided in an embodiment of the present application;

[0077] FIG21 is a flow chart of a battery monitoring method provided in an embodiment of the present application;

[0078] FIG22 is a schematic diagram of the sound field of an ultrasonic transducer module provided in an embodiment of the present application;

[0079] FIG23 is a schematic diagram of ultrasonic scanning results of a battery cell provided in an embodiment of the present application;

[0080] FIG24 is a schematic diagram of ultrasonic scanning results of a battery cell provided in an embodiment of the present application;

[0081] FIG25 is a schematic diagram of ultrasonic scanning results of a battery cell provided in an embodiment of the present application;

[0082] FIG26 is a schematic diagram of ultrasonic scanning results of a battery cell provided in an embodiment of the present application;

[0083] FIG27 is a schematic diagram of ultrasonic scanning results of a battery cell provided in an embodiment of the present application;

[0084] FIG28 is a schematic diagram of a battery cell for locating risk provided in an embodiment of the present application;

[0085] Figure 29 is a schematic diagram of a battery risk level provided in an embodiment of the present application. DETAILED DESCRIPTION

[0086] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0087] In the description of the present invention, it should be understood that the orientations or positional relationships indicated by terms such as "vertical", "upper", "lower", "top", "side", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0088] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0089] According to statistics from the National Emergency Management Department, the spontaneous combustion rate of new energy vehicles nationwide is 0.7 per 10,000 vehicles, with an average of approximately eight new energy vehicles catching fire each day. As new energy vehicles become more common, the number of power battery spontaneous combustion incidents is expected to increase further. Therefore, preventing the life-threatening effects of battery spontaneous combustion has drawn considerable attention.

[0090] In order to avoid the above problems, in an embodiment of the present application, a technology is proposed that can monitor the working status of the power battery in real time. The technology uses the battery body for power supply, and uses ultrasonic sensors to make early judgments and warnings on the internal structure of the battery and spontaneous combustion conditions, prompting battery replacement or emergency escape.

[0091] An embodiment of the present application provides a battery cell (hereinafter referred to as a battery cell) that can be detected in situ. The battery cell includes a protective shell and internal components arranged inside the protective shell.

[0092] In an embodiment of the present application, as shown in Figure 1, the internal components include: a battery winding needle; an ultrasonic sensor module that is pasted to the surface of the battery winding needle by winding; and a battery tape layer that is pasted to the surface of the ultrasonic sensor module by winding; wherein the ultrasonic sensor module is used to transmit ultrasonic transmission signals, receive ultrasonic reflection echoes to perform ultrasonic detection, and perform real-time in-situ detection of battery cells through ultrasonic detection.

[0093] In the embodiments of the present application, an ultrasonic sensor module is packaged and used together with a battery. Because ultrasound has the characteristics of non-destructive penetrating detection, high resolution, low cost, and long life, the use of ultrasonic sensor modules to perform ultrasonic detection technology can achieve real-time in-situ detection of batteries in service, timely diagnosis and prediction of safety hazards, and avoid the threat to life posed by battery self-explosion. The battery cells in the embodiments of the present application can be electrolyte batteries or solid-state batteries. Compared with electrolyte batteries, solid-state batteries use solid ion transport instead of liquid electrolytes. Therefore, the ultrasonic sensor module can still be packaged inside the battery cell for real-time in-situ safety monitoring.

[0094] Specifically, as shown in Figures 2 and 3, an ultrasonic sensor module is positioned at the center of the entire battery cell and assembled with a battery winding needle. Through electrolyte / solid electrolyte coupling, ultrasonic signals are transmitted around the battery, and real-time imaging is achieved through ultrasonic reflection echoes from the battery winding layer. Because ultrasonic testing is less affected by temperature and operating conditions, it can not only monitor the internal density of battery cells during production, but a more important application area of ​​this invention is in-situ real-time testing and monitoring of battery cells throughout their service lifecycle.

[0095] Among them, the ultrasonic sensor module can adopt a flexible and bendable design to be folded onto the surface of the battery winding needle, and then wound into the interior of the battery cell together with the battery winding layer.

[0096] In a possible implementation, the winding shape corresponding to the winding includes: cylindrical; or, cubic; or, elliptical.

[0097] In this implementation, battery cells can have different winding configurations. In addition to cylindrical batteries, there are also cubic batteries, elliptical batteries, and polymer batteries, all of which can be used to perform real-time in-situ safety monitoring of batteries. For example, Figure 4 shows a cylindrically wound battery cell.

[0098] In one possible implementation, the ultrasonic sensor module includes a single ultrasonic sensor.

[0099] In this implementation, a single ultrasonic sensor receives an ultrasonic reflection echo, and the internal state of the battery cell is monitored by comparing the waveform of the current ultrasonic reflection echo with the waveform of the ultrasonic reflection echo in a normal state.

[0100] Among them, the principle of real-time monitoring by the ultrasonic sensor module is as follows: If bubbles and lithium metal dendrites appear inside the battery cell due to abnormal conditions such as overcharging, according to the propagation theory of ultrasound under acoustic impedance mismatch, a relatively strong ultrasonic reflection echo will be generated. After being transmitted to the ultrasonic sensor module, the status of bubbles and lithium metal dendrites can be monitored in real time. When the limit value is reached, a battery safety warning will be issued and a prompt will be given to replace the battery or perform battery maintenance.

[0101] For example, as shown in FIG5 , it shows the signal state of the ultrasonic reflection echo when the battery cell is in a normal state; as shown in FIG6 , it shows the signal state of the ultrasonic reflection echo when there are bubbles in the battery cell, and the echo has an obvious bubble reflection signal; as shown in FIG7 , it shows the signal state of the ultrasonic reflection echo when there are lithium metal dendrites in the battery cell, and the echo has an obvious lithium metal dendrite reflection signal. It can be understood that the signal waveforms in FIG5 to FIG7 are only examples, and the present application does not impose any limitation on this. For example, the reflection signal corresponding to the presence of bubbles / lithium metal dendrites in the battery cell can be a boundary reflection signal with an amplitude much larger than the conventional one, or a boundary reflection signal with an amplitude much smaller than the conventional one.

[0102] In a possible implementation, the ultrasonic sensor module includes a plurality of ultrasonic sensors, and the plurality of ultrasonic sensors form a multi-channel array structure.

[0103] In this implementation, since the ultrasonic sensor module is wound inside the battery unit, the ultrasonic sensor module can adopt a multi-channel array structure to realize the imaging function, and the interior of the ultrasonic unit can be monitored more clearly through the imaging function.

[0104] In a possible implementation, the array structure includes: a linear array structure or a planar array structure.

[0105] In this implementation, two different array arrangements of ultrasonic sensor modules are provided: a linear array structure as shown in Figures 8 and 9, and a planar array structure as shown in Figures 10 and 11. The linear array structure includes m rows of ultrasonic sensors, while the planar array structure includes m rows and n columns of ultrasonic sensors.

[0106] In one possible implementation, the structure of each ultrasonic sensor in the ultrasonic sensor module is as follows, including the following layers connected in sequence from bottom to top: a base layer, used to adhere to the surface of the battery winding needle and carry the piezoelectric material layer; a piezoelectric material layer, used to radiate ultrasonic transmission signals outward and receive ultrasonic reflection echoes; an acoustic matching layer, used to reduce the acoustic impedance difference between the piezoelectric material and the battery winding layer; and a sealing layer, used to encapsulate and protect the ultrasonic sensor.

[0107] In this implementation, as shown in FIG12 , the base layer, the piezoelectric material layer, the acoustic matching layer, and the sealing layer are combined to form an effective ultrasonic sensor element, which emits ultrasonic waves outward under high-voltage drive and can also receive reflected ultrasonic echoes, and use the ultrasonic reflection echoes to detect battery cells.

[0108] Specifically, the characteristics and functions of each functional layer of the ultrasonic sensor are as follows:

[0109] (1) Base layer: One side carries the piezoelectric material layer, and the other side adheres to the surface of the battery winding needle. At the same time, it needs to suppress the backscattered signal when the piezoelectric material is excited. Generally, flexible and high-temperature resistant polymer materials are used, such as high-temperature resistant PET (polyester) film, high-temperature PI (polyimide) film material, PEEK (polyetheretherketone) film, etc. Metal materials such as stainless steel can also be used. The ideal thickness is less than 0.2mm.

[0110] (2) Piezoelectric material layer: The piezoelectric material layer is the core layer of the ultrasonic sensor, which will radiate ultrasonic emission signals outward under the excitation of high-voltage pulses.

[0111] The frequency of the radiated ultrasonic emission signal is related to the material thickness. In the thickness vibration mode, the material thickness is about half of the wavelength of the ultrasonic signal, that is, f c =λ / 2, where f c λ represents the material thickness, and λ represents the wavelength. Therefore, the thinner the piezoelectric material, the higher the frequency of the generated ultrasonic signal, and the higher the resolution for detecting abnormalities. The design of the piezoelectric material must meet the specific requirements of the defect detection target. As shown in Figure 13, the ultrasonic signal must penetrate the multilayer composite material consisting of the positive electrode material layer, the current collector layer, and the separator negative electrode material layer. The composite material must also be immersed in the electrolyte.

[0112] In a possible implementation, the thickness of the piezoelectric material layer is 1 um-1000 um, so that the frequency of the ultrasonic emission signal is designed to be 0.5 MHz-50 MHz.

[0113] It is understood that in the embodiment of the present application, ultrasonic reflection echo is used for defect detection and battery in vivo imaging. According to the ultrasonic propagation theory, for vertically incident sound waves, the ultrasonic reflection echo is related to the difference in interface acoustic impedance, and its reflection coefficient is Z1 and Z2 are the acoustic impedance values ​​of the materials on both sides of the interface, and the acoustic impedance values ​​are related to the density and Young's modulus of the battery material. For example, for a 46800 battery, the thickness and acoustic impedance of each material are approximately: positive electrode material (~80um, ~5MRely), negative electrode material (~120um, ~5MRely), current collecting layer (~10um, ~15MRely), copper current collecting layer (~10um, ~32MRely), diaphragm (~30um, ~1.8MRely, after being soaked in electrolyte). According to the parameters of the above-mentioned materials, it can be seen that the maximum resolution of the ultrasonic sensor only needs to reach 10um to clearly distinguish the various structures inside the battery cell, and the frequency of the ultrasonic sensor needs to be designed to be above 100MHz. On the other hand, as shown in the exemplary ultrasonic transmission signal and ultrasonic receiving signal in Figure 14, high-frequency ultrasound will rapidly attenuate with the propagation distance, and the attenuation coefficient is positively correlated with the ultrasonic frequency. In order to take into account the detection depth, it is necessary to avoid designs with too high an ultrasonic frequency.

[0114] In this implementation, since the current collecting layer with relatively low thickness in the battery cell has little impact on battery safety, in order to take into account both detection depth and resolution, the frequency of the ultrasonic transmission signal can be designed to be 0.5MHz-50MHz, and the thickness of the piezoelectric material can be designed according to the requirements of the detection frequency, and the thickness of the piezoelectric material can be designed to be 1um-1000um.

[0115] For example, for flexible PVDF-TrFE piezoelectric materials, their load capacity is relatively weak, and the corresponding suitable thickness range is 5um-300um; for PZT-type piezoelectric films or bulk piezoelectric materials, their suitable thickness is 1um-1000um, and other types of materials can be designed and selected according to the frequency constant of the material; if an ultrasonic sensor with a frequency of about 10MHz is designed to detect a battery, the optimized design thickness for PVDF-TrFE is about 12um, and for PZT film, the optimized thickness is about 100um.

[0116] (3) Acoustic matching layer: The function of the acoustic matching layer is to reduce the acoustic impedance difference between the piezoelectric material layer and the detection object, so that more energy can be transferred to the medium. Its thickness is generally half of the wavelength, and the materials that can be selected include DAF film.

[0117] (4) Sealing layer: The main function of the sealing layer is to encapsulate and protect the ultrasonic sensor, prevent the electrolyte from corroding the ultrasonic sensor, and play a role in waterproofing, moisture-proofing and sealing protection. The thickness needs to be less than 20um. Optional materials include PVDF film, Parylene film, etc.

[0118] In one possible implementation, one end of the battery winding needle leads to a flexible circuit board connected to the ultrasonic sensor module, and a smart chip is mounted on the flexible circuit board. The smart chip is powered by a battery unit and is used as the driving and imaging unit of the ultrasonic sensor module.

[0119] In this implementation, one end of the battery winding needle can use FPC (Flexible Printed Circuit) to lead out the array element signal of the ultrasonic transducer module, and together with it, the smart chip with image processing function (such as ASIC (Application Specific Integrated Circuit) chip) is mounted on the FPC. The design of the smart chip leaking to the outside of the battery cell can facilitate signal communication between battery cells, and the battery cell can also directly power the smart chip. For example, Figure 15 shows a schematic diagram of the connection between the battery cell using a linear array ultrasonic sensor and the smart chip, and Figure 16 shows a schematic diagram of the connection between the battery cell using a planar array ultrasonic sensor and the smart chip.

[0120] In one possible implementation, the smart chip includes: a front-end transceiver module for stimulating the ultrasonic sensor module to transmit ultrasonic transmission signals and receiving and processing ultrasonic reflection echoes; a beam control module for performing delay control and forming the ultrasonic reflection echoes into a grayscale matrix; an image processing module for performing image processing based on the grayscale matrix to identify abnormal information in the battery cell; a main control module for performing logical control of the smart chip; a communication module for managing the communication interface of the smart chip; and a power management module for performing voltage management.

[0121] In this implementation, the driving and imaging unit of the ultrasonic sensor is an intelligent chip (such as an ASIC chip) with small-scale ultrasonic imaging capabilities. As shown in Figure 17, the functions and characteristics of each module of the intelligent chip can be as follows:

[0122] (1) Front-end transceiver module: The front-end transceiver module mainly completes the excitation of the ultrasonic array elements and the reception of ultrasonic reflected echoes, and at the same time performs signal processing processes such as signal amplification, filtering and digital-to-analog conversion after signal reception.

[0123] (2) Beam control module: The beam control module mainly completes the delay control of the transmission or reception of the ultrasonic array module, realizes the phase control function, and forms the received echo signal into a grayscale matrix.

[0124] (3) Image processing module: The image processing module completes grayscale matrix coordinate conversion, pixel enhancement, image comparison, abnormal point standard and other functions, and ultimately identifies risky battery cells and further defect locations, and provides risk level assessment and prediction based on the image.

[0125] (4) Main control module: performs logical control and comprehensively manages the operation of each functional module.

[0126] (5) Communication module: manages various communication interfaces, as well as the communication protocols and interfaces between the internal modules of the smart chip.

[0127] (6) Power management module: manages the voltage collected from the battery cell, performs voltage stabilization and voltage conversion functions, and ensures that the entire chip has a stable operating voltage.

[0128] To sum up, the technical solution provided in the embodiment of the present application is to wind the ultrasonic sensor on the surface of the battery winding needle, and to wind the battery tape layer on the surface of the ultrasonic sensor, so that the ultrasonic sensor module and the battery can be packaged together for use. Since ultrasonic waves have the characteristics of non-destructive penetration detection, and have high resolution, low cost and long life, the ultrasonic detection technology is performed by using the ultrasonic sensor module inside the battery cell, which can perform real-time in-situ detection of battery cells in service, avoiding the risk of battery self-explosion.

[0129] An embodiment of the present application further provides an in-situ detectable battery pack, which includes a plurality of battery cells as described in the above embodiment, and the smart chip of each battery cell is connected via a communication bus.

[0130] In this embodiment, as shown in Figure 18, for a battery pack containing multiple battery cells, the ultrasonic sensor modules in each battery cell can be connected via a communication bus interface on the smart chip, thereby transmitting the in-situ detection results of each ultrasonic sensor module to a host computer. This application does not impose any restrictions on the number of battery cells in the battery pack or the arrangement of the battery cells.

[0131] In summary, the battery pack in this embodiment can ensure the overall safety of the battery pack by providing battery units with a real-time in-situ detection function.

[0132] An embodiment of the present application also provides an early warning system, which is connected to the battery pack as described in the above embodiment. The early warning system supports prompting of risky battery cells in the battery pack. Risky battery cells are battery cells that have abnormal information detected in real time in situ through ultrasonic detection.

[0133] In this embodiment, the ultrasonic sensor module in each battery cell in the battery pack is connected to the smart chip through an FPC, and the smart chip outside each battery cell can upload the detection data directly to the early warning system through a communication bus (such as a CAN (Controller Area Network) communication bus), or as shown in Figure 19, first upload it to the main control system of a terminal such as a car or an energy storage station. The main control system performs comprehensive processing and judgment on the reported detection data of each battery cell. After the main control system comprehensively processes the data, it can pass the results to the early warning system, and the early warning system outputs the detection results and issues early warnings, forming a distributed real-time battery monitoring and early warning system.

[0134] Among them, the warning system can use one or more of a variety of perception methods such as voice, vision, touch, etc. to issue warnings, and this application does not limit this.

[0135] For example, Figure 20 shows a schematic diagram of displaying warning system prompts on the central control screen of an electric vehicle. Just like other important electric vehicle operating information such as battery power, the safety status of the battery cells in an electric vehicle (such as battery risk level and abnormal information) can also be obtained through battery ultrasonic testing and notified to the driver in real time, making it easier for the driver to use and maintain the battery cells and understand the safety status, and buying time for escape in an emergency.

[0136] To sum up, the early warning system in this embodiment is connected to the battery pack, and a battery cell with real-time in-situ detection function is provided in the battery pack. The early warning system can prompt the risky battery cells detected in the battery pack to help users understand the safety status of the battery pack.

[0137] The present application also provides a battery monitoring method, which is applied to the battery cell described in the above embodiment. As shown in FIG21 , the method may include the following steps:

[0138] Step 2110: The ultrasonic sensor module transmits an ultrasonic transmission signal to scan the interior of the battery cell.

[0139] In this embodiment, an ultrasonic sensor module is encapsulated inside the battery cell. Driven by the smart chip corresponding to the ultrasonic sensor module, the ultrasonic sensor module supports transmitting ultrasonic transmission signals to scan the interior of the battery cell, such as the battery tape layer.

[0140] Step 2120: Receive the ultrasonic reflection echo generated after scanning through the ultrasonic sensor module.

[0141] In this embodiment, the ultrasonic transmission signal emitted by the ultrasonic sensor may generate an ultrasonic reflection echo.

[0142] Step 2130: The ultrasonic reflected echo is transmitted to the smart chip corresponding to the ultrasonic sensor module through the ultrasonic sensor module.

[0143] In this embodiment, after the ultrasonic sensor module receives the ultrasonic reflected echo, it transmits the ultrasonic reflected echo to the corresponding smart chip.

[0144] Step 2140: Analyze the ultrasonic reflection echo through the smart chip to identify abnormal information in the battery cell.

[0145] In this embodiment, the smart chip has an ultrasonic imaging function, which can analyze the ultrasonic reflection echo and identify abnormal information in the battery cell.

[0146] Among them, for the linear array ultrasonic transducer module, the sound field it forms is an annular sound field, which can detect and image the cross section of the battery cell, as shown in Figure 22. Similarly, the planar array ultrasonic transducer module can also form an annular sound field, and the annular sound field can be further subdivided into fan-shaped areas in different directions, achieving the effect of 3D scanning of the battery cell and forming a 3D image.

[0147] In a possible implementation, the abnormality information includes: the height of the abnormal point in the battery cell; and / or the position of the abnormal point in the battery cell.

[0148] In this implementation, the smart chip uses ultrasonic analysis to identify abnormal points in the battery cell and specifically identify the height and / or orientation of the abnormal points. The abnormal points are locations where abnormalities occur in the battery cell, such as bubble points, lithium metal dendrites, and so on.

[0149] For example, bubbles are in a low acoustic impedance area inside the battery cell. Because its acoustic impedance is about 0.04 MRaly, the ultrasonic signal will have the strongest reflection signal at the interface. When lithium is deposited from the anode material, lithium dendrites will be generated. The acoustic impedance of metallic lithium is 2.6 MRaly, which is mismatched with the acoustic impedance of the positive electrode material and will also produce a certain amount of ultrasonic reflection echo. After the lithium battery tape is soaked in electrolyte, the electrolyte can act as an acoustic coupling agent, which is more conducive to the propagation efficiency of the ultrasonic signal and improves the detection accuracy. The ultrasonic detection results of battery cells are divided into the following common situations:

[0150] (1) As shown in FIG23 , the linear array ultrasonic detection results show that the ultrasonic transmission signal is transmitted to scan the interior of the battery cell, and no abnormal acoustic reflection area or impedance mismatch area is found.

[0151] (2) As shown in the linear array ultrasonic detection results in Figure 24, a single abnormal point appears somewhere in the battery cell. After identification by the smart chip, it indicates that an abnormality occurs at a certain height of the battery cell.

[0152] (3) As shown in the array ultrasonic detection results in Figure 25, a single abnormal point appears somewhere in the battery cell. After identification by the smart chip, it is prompted that an abnormality occurs at a certain height and direction of the battery cell.

[0153] (4) As shown in the array ultrasonic detection results in Figure 26, multiple abnormal points appear at a certain height of the battery cell. After identification by the smart chip, it is indicated that abnormalities occur in multiple directions at a certain height of the battery.

[0154] (5) As shown in the area array ultrasonic detection results in Figure 27, abnormal points appear at certain heights of the battery. After identification by the smart chip, it is indicated that the orientation of certain heights of the battery is abnormal.

[0155] In a possible implementation, the smart chip corresponds to a displacement address code; and after step 2140, the method further includes: reporting an ultrasonic scanning recognition result through the smart chip, wherein the ultrasonic scanning recognition result carries the displacement address code and abnormal information in the battery cell.

[0156] In this implementation, the smart chip on each battery cell has a displacement address code, which can be used to locate the corresponding battery cell based on the address. When an ultrasonic scan detects an abnormality in a battery cell, the ultrasonic scan identification result, which carries the displacement address code and the abnormality information in the battery cell, is reported to the early warning system. The early warning system can then locate the specific battery cell based on the displacement address code. For example, as shown in Figure 28, the risk battery cell BAT (2, 2, 3) can be located to the specific abnormal point through real-time internal scanning of the risk battery cell.

[0157] In a possible implementation, the battery unit has a battery risk level; and reporting the ultrasonic scanning identification result through the smart chip includes: reporting the ultrasonic scanning identification result through the smart chip according to the information reporting frequency corresponding to the current battery risk level.

[0158] In this implementation, each battery cell has a battery risk level determined in real time. The battery risk level is used to indicate the risk level of this battery cell. The information reporting frequency of the ultrasonic scanning identification results detected by each battery cell is determined according to the battery risk level. Specifically, the higher the risk level, the higher the information reporting frequency, and the lower the risk level, the lower the information reporting frequency, so as to reasonably set the information reporting frequency of the ultrasonic scanning identification results.

[0159] The battery risk level can be determined based on at least one of the following information: the current number of abnormal points in the battery cell; the current size of the abnormal points in the battery cell; the trend of changes in the number of abnormal points in the battery cell; and the trend of changes in the size of the abnormal points in the battery cell. For example, the greater the current number of abnormal points in the battery cell, the larger the current size of the abnormal points, the more rapidly the number of abnormal points increases, and the more rapidly the size of the abnormal points increases, the higher the risk level indicated by the battery risk level. The fewer the current number of abnormal points in the battery cell, the smaller the current size of the abnormal points, the more rapidly the number of abnormal points decreases, and the more rapidly the size of the abnormal points decreases, the lower the risk level indicated by the battery risk level.

[0160] For example, the reporting and presentation of the ultrasonic scanning identification results of the battery cell can be reported at different frequencies according to the battery risk level. Figure 29 shows a comprehensive reporting method: due to the low power consumption of ultrasonic detection, the smart chip can scan a random part of the battery cell at the second level. If the battery cell is detected to be safe and normal for a long time, the data can be reported at the day level, as shown in the L0 level battery risk level in Figure 28; when a battery cell abnormality is found through routine scanning and is in the early stages of development and will not pose a threat to safety in a short time, the data can be reported at the day level to improve the battery The risk level is L1. As the battery cell is used, the abnormal point will gradually grow larger during repeated charging and discharging, threatening the safety of the battery. If the size of the abnormal point becomes large enough to increase the probability of battery cell explosion, the smart chip will automatically increase the scanning and detection frequency of the battery cell and the information reporting frequency, and increase the battery risk level to L2. If the size of the abnormal point reaches the preset proportion range of the battery cell self-explosion size (such as 30%-80%), the detection frequency will be increased to the second level, the battery risk level will reach L3, and the user will be informed to stop using the battery and stay away from the risky battery cell in time to protect personal safety.

[0161] It is understood that the above-described battery monitoring method and corresponding early warning system can be widely applied in critical power battery safety scenarios, such as electric vehicles, energy storage power stations, and outdoor high-power mobile power supplies. Each battery cell in the battery pack connected to this early warning system uses an ultrasonic sensor encapsulated within the battery cell. Each battery cell uses a sonar-like scanning method to detect internal defects, promptly reporting the defect level and providing emergency escape warnings.

[0162] To summarize, the battery monitoring method in this embodiment transmits an ultrasonic transmission signal through the ultrasonic sensor module to scan the inside of the battery cell; receives the ultrasonic reflection echo generated after the scanning through the ultrasonic sensor module; transmits the ultrasonic reflection echo to the smart chip corresponding to the ultrasonic sensor module through the ultrasonic sensor module; analyzes the ultrasonic reflection echo through the smart chip to identify abnormal information in the battery cell; thereby performing real-time in-situ detection of the battery cell, monitoring the working status of the battery cell in real time, and improving safety.

[0163] All of the above optional technical solutions can be combined in any way to form optional embodiments of the present invention, that is, any multiple embodiments can be combined to meet the needs of different application scenarios. They are all within the scope of protection of this application and will not be described in detail here.

[0164] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An in-situ detectable battery cell, characterized in that, the battery cell includes a protective case and internal components disposed inside the protective case, and the internal components include: a battery winding pin; an ultrasonic sensor module pasted to the surface of the battery winding pin by winding; a battery winding tape layer pasted to the surface of the ultrasonic sensor module by winding; wherein, the ultrasonic sensor module is used to emit ultrasonic emission signals, receive ultrasonic reflected echoes to perform ultrasonic detection, and perform real-time in-situ detection on the battery cell through ultrasonic detection.

2. The battery cell according to claim 1, characterized in that, the ultrasonic sensor module includes a plurality of ultrasonic sensors, and the plurality of ultrasonic sensors form a multi-channel array structure.

3. The battery cell according to claim 2, characterized in that, the array structure includes: a linear array structure or a planar array structure.

4. The battery cell according to claim 1, characterized in that, the ultrasonic sensor module includes a single ultrasonic sensor.

5. The battery cell according to claim 2 or 4, characterized in that, the ultrasonic sensor includes the following layers connected in sequence from bottom to top: a base layer, which is used to fit to the surface of the battery winding pin and carry a piezoelectric material layer; a piezoelectric material layer, which is used to radiate the ultrasonic emission signal outward and receive the ultrasonic reflected echo; an acoustic matching layer, which is used to reduce the acoustic impedance difference between the piezoelectric material and the battery winding tape layer; a sealing layer, which is used to encapsulate and protect the ultrasonic sensor.

6. The battery cell according to claim 5, characterized in that, the thickness of the piezoelectric material layer is 1um - 1000um, so that the frequency of the ultrasonic emission signal is designed to be 0.5MHz - 50MHz.

7. The battery cell according to claim 1, characterized in that, a flexible circuit board connected to the ultrasonic sensor module is led out from one end of the battery winding pin, an intelligent chip is mounted on the flexible circuit board, the intelligent chip is powered by the battery cell, and the intelligent chip is used as the driving and imaging unit of the ultrasonic sensor module.

8. The battery cell according to claim 7, characterized in that, the intelligent chip includes: a front-end transceiver module, which is used to excite the ultrasonic sensor module to emit the ultrasonic emission signal, and receive and process the ultrasonic reflected echo; a beam control module, which is used to perform delay control and form a grayscale matrix of the ultrasonic reflected echo; an image processing module, which is used to perform image processing according to the grayscale matrix and identify abnormal information in the battery cell; a main control module, which is used to perform logical control on the intelligent chip; a communication module, which is used to manage the communication interface of the intelligent chip; a power management module, which is used to perform voltage management.

9. The battery cell according to claim 1, characterized in that, the corresponding winding forms of winding include: cylindrical; or, cubic; or, elliptical.

10. An in-situ detectable battery pack, characterized in that, The battery pack includes a plurality of battery cells as described in any one of claims 1 to 9, and the intelligent chips of each battery cell are connected through a communication bus.

11. An early warning system, characterized in that, the early warning system is connected to the battery pack as described in claim 10, and the early warning system supports prompting for risk battery cells in the battery pack, and the risk battery cells are battery cells in which abnormal information is detected in real time in situ through ultrasonic detection.

12. A battery monitoring method, characterized in that, the method is applied to the battery cells as described in any one of claims 1 to 9, and the method includes: emitting an ultrasonic emission signal through the ultrasonic sensor module to scan the inside of the battery cell; receiving the ultrasonic reflected echo generated after scanning through the ultrasonic sensor module; transferring the ultrasonic reflected echo to the intelligent chip corresponding to the ultrasonic sensor module through the ultrasonic sensor module; analyzing the ultrasonic reflected echo through the intelligent chip to identify abnormal information in the battery cell.

13. The method according to claim 12, characterized in that, the abnormal information includes: the height of the abnormal point in the battery cell; and / or, the azimuth of the abnormal point in the battery cell.

14. The method according to claim 12, characterized in that, the intelligent chip corresponds to a displacement address code; the method further includes: reporting the ultrasonic scan recognition result through the intelligent chip, and the ultrasonic scan recognition result carries the displacement address code and the abnormal information in the battery cell.

15. The method according to claim 14, characterized in that, the battery cell has a battery risk level; the reporting the ultrasonic scan recognition result through the intelligent chip includes: reporting the ultrasonic scan recognition result through the intelligent chip according to the information reporting frequency corresponding to the current battery risk level.

16. The method according to claim 15, characterized in that, the battery risk level is determined based on at least one of the following information: the current number of abnormal points in the battery cell; the current size of the abnormal points in the battery cell; the change trend of the number of abnormal points in the battery cell; the change trend of the size of the abnormal points in the battery cell.

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