A full-solid battery thermal runaway diagnosis method based on displacement detection

Abstract

This invention discloses a method for diagnosing thermal runaway in all-solid-state batteries based on displacement detection, belonging to the field of battery diagnostic technology. The method includes acquiring the structural configuration information of the all-solid-state battery cell, configuring a displacement sensor on the surface of the battery casing of the all-solid-state battery cell, monitoring the deformation of the battery casing in real time using the displacement sensor, collecting the displacement of the battery casing caused by the expansion of the thermal expansion material layer to obtain a displacement detection signal, performing signal conditioning processing on the displacement detection signal, and determining the location of the faulty battery cell that has experienced thermal runaway when the processed displacement signal value is greater than or equal to a preset displacement threshold. This solves the technical problem of slow diagnostic response caused by thermal runaway detection methods based on temperature or voltage sensors in the prior art due to delays in thermal conduction or lags in electrical changes.

Description

Technical Field

[0001] This invention belongs to the field of battery diagnostic technology, and particularly relates to a method for diagnosing thermal runaway in all-solid-state batteries based on displacement detection. Background Technology

[0002] All-solid-state batteries (ASSBs) offer advantages such as high energy density, good safety, and a wide operating temperature range due to their use of solid electrolytes instead of traditional liquid electrolytes, making them a key development direction for next-generation power batteries. In recent years, with the continuous growth in demand for high-performance batteries from fields such as electric vehicles and energy storage systems, the research and industrialization of all-solid-state batteries has been accelerating.

[0003] However, in the pursuit of high energy density, all-solid-state batteries still face the risk of thermal runaway. When a short circuit, overcharging, or other abnormal conditions occur inside the battery, abnormal heat will be generated in local areas. If the heat cannot be dissipated in time, the temperature will continue to rise, eventually leading to a thermal runaway accident.

[0004] While thermally responsive blocking materials provide a built-in safety protection mechanism for all-solid-state batteries, existing technologies still have significant shortcomings in the diagnosis of thermal runaway. Currently, battery management systems primarily rely on temperature sensors or voltage sensors to identify thermal runaway. Temperature sensors determine whether thermal runaway has occurred by monitoring temperature changes on the battery surface or inside, while voltage sensors identify fault states by detecting abnormal fluctuations in battery terminal voltage.

[0005] The aforementioned traditional detection methods inherently suffer from response delay issues. For temperature detection, it takes time for heat to conduct from the heat source inside the battery to the sensor location. This heat conduction process prevents the temperature sensor from detecting temperature anomalies immediately upon the occurrence of thermal runaway. Similarly, for voltage detection, changes in battery terminal voltage are electrical characteristics that only become apparent after thermal runaway has progressed to a certain stage, also resulting in a detection lag.

[0006] The direct consequence of delayed diagnosis is the untimely location and isolation of faulty batteries. In a battery module, multiple battery cells are typically connected in series or parallel. When a battery cell experiences thermal runaway, if it cannot be quickly isolated from the system, the heat generated by the faulty cell will spread to adjacent cells through thermal conduction, and electrical effects may also be transferred to other healthy cells through parallel circuits, potentially triggering a chain reaction of thermal runaway and leading to a safety accident for the entire battery module.

[0007] Therefore, in practical application environments, factors such as mechanical vibration and temperature changes may interfere with displacement detection, and accurately extracting thermal expansion trigger signals from complex backgrounds is an urgent problem to be solved. Summary of the Invention

[0008] To address the technical problems mentioned above, this invention discloses a method for diagnosing thermal runaway in all-solid-state batteries based on displacement detection, comprising the following steps: S1: Obtain the structural configuration information of the all-solid-state battery cell, which includes a solid electrolyte layer, an electrode layer, and a thermal expansion material layer disposed between the solid electrolyte layer and the electrode layer. The thermal expansion material layer expands in volume when a preset trigger temperature is reached. S2: A displacement sensor is disposed on the surface of the battery casing of the all-solid-state battery cell. The displacement sensor is mechanically coupled to the battery casing and is used to sense the deformation transmitted to the battery casing when the thermal expansion material layer expands. S3: The deformation of the battery casing is monitored in real time by the displacement sensor, and the displacement of the battery casing caused by the expansion of the thermal expansion material layer is collected to obtain a displacement detection signal; S4: Perform signal conditioning processing on the displacement detection signal, including filtering and amplification, to obtain the processed displacement signal value; S5: Compare the processed displacement signal value with a preset displacement threshold. When the processed displacement signal value is greater than or equal to the preset displacement threshold, generate a thermal runaway trigger signal. S6: The thermal runaway trigger signal and the identification information of the all-solid-state battery cell are transmitted to the battery management system, which then determines the location of the faulty battery cell that has experienced thermal runaway based on the identification information.

[0009] Preferably, the displacement sensor is a strain gauge, which is fixed to the surface of the battery casing by adhesive bonding, and the detection sensitivity of the strain gauge is determined according to the preset expansion range of the thermal expansion material layer.

[0010] Preferably, the displacement sensor is an optical fiber sensor, which is arranged along the surface of the battery casing, and the displacement detection signal is obtained by detecting the strain change of the optical fiber.

[0011] Preferably, the displacement sensor is disposed on the battery casing in a region corresponding to the thermal expansion material layer, so that the displacement sensor can directly sense the displacement change on the deformation transmission path caused by the expansion of the thermal expansion material layer.

[0012] Preferably, the preset displacement threshold is determined based on the following parameters: obtaining the expansion coefficient of the thermal expansion material layer; obtaining the stiffness parameter of the battery casing; calculating the theoretical displacement amount transmitted to the battery casing when the thermal expansion material layer expands at the preset trigger temperature based on the expansion coefficient and the stiffness parameter; and multiplying the theoretical displacement amount by a preset safety factor to obtain the preset displacement threshold.

[0013] Preferably, the signal conditioning process in step S4 further includes temperature compensation processing, specifically: obtaining the current temperature value of the environment where the displacement sensor is located; compensating and correcting the displacement detection signal according to the current temperature value and a preset temperature compensation coefficient; filtering and amplifying the compensated and corrected signal to obtain the processed displacement signal value.

[0014] Preferably, a plurality of displacement sensors are disposed on the surface of the battery casing, and each displacement sensor is distributed at a different position on the battery casing; in step S3, the displacement detection signals output by each displacement sensor are collected respectively; in step S5, when the processed displacement signal value corresponding to any displacement sensor is greater than or equal to the preset displacement threshold, a thermal runaway trigger signal is generated.

[0015] Preferably, step S5 further includes: performing a comprehensive analysis on the processed displacement signal values ​​corresponding to each displacement sensor; determining the location region where the thermal expansion material layer expands based on the distribution characteristics of each processed displacement signal value; and transmitting the location region and the thermal runaway trigger signal together to the battery management system.

[0016] Preferably, for a battery module containing multiple all-solid-state battery cells, a displacement sensor is configured on each of the all-solid-state battery cells, and each displacement sensor independently executes steps S3 to S5; the battery management system receives the thermal runaway action trigger signal corresponding to each of the all-solid-state battery cells, and determines the thermal runaway state of each of the all-solid-state battery cells according to the identification information.

[0017] Preferably, the method further includes a diagnostic confirmation step: after generating the thermal runaway trigger signal, continuously monitoring the change trend of the processed displacement signal value within a preset time window; when the processed displacement signal value remains above the preset displacement threshold within the preset time window, confirming that the thermal runaway trigger signal is valid; and transmitting the confirmed valid thermal runaway trigger signal to the battery management system.

[0018] This invention discloses a method for diagnosing thermal runaway in all-solid-state batteries based on displacement detection. By configuring a displacement sensor on the surface of the battery casing of the all-solid-state battery cell, the sensor is mechanically coupled to the battery casing. This allows for real-time monitoring of minute deformations transmitted to the battery casing as the thermal expansion material layer expands. The method collects and conditions the displacement signal, comparing the processed signal value with a preset displacement threshold. When the displacement signal value reaches the preset threshold, a thermal runaway trigger signal is generated. This trigger signal, along with the battery cell identification information, is transmitted to the battery management system to locate the faulty battery cell. This method solves the technical problem of slow diagnostic response caused by thermal runaway detection methods based on temperature or voltage sensors due to delays in thermal conduction or lags in electrical changes. The method offers the following advantages: 1. Since the displacement sensor directly detects the physical action of thermal expansion of the material layer itself, rather than the indirect characterization of the thermal runaway process, it can capture the displacement change signal at the first moment triggered by the thermal expansion of the material. Compared with the detection methods of traditional temperature sensors that need to wait for heat conduction and voltage sensors that need to wait for electrical characteristics to appear, the diagnostic response time is significantly shortened.

[0019] 2. The generation of displacement signals precedes the large-scale conduction of temperature and significant changes in voltage, enabling this method to issue early warnings at an earlier stage of thermal runaway development. This provides the battery management system with more response time, facilitating timely implementation of protective measures and achieving early warning of thermal runaway.

[0020] 3. By associating displacement sensors with battery cell identification information, the battery management system can accurately identify the specific battery cell that has failed when it receives a thermal runaway trigger signal, providing precise target location for subsequent fault isolation and maintenance, and improving the accuracy of faulty battery cell location. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the overall steps of a displacement-detection-based thermal runaway diagnosis method for all-solid-state batteries in an embodiment of the present invention. Figure 2 This is a flowchart illustrating the specific steps of step S5 in an embodiment of the present invention. Figure 3 This is a flowchart illustrating step S7 of another specific embodiment of the present invention. Figure 4 This is a flowchart illustrating the process judgment of a specific embodiment of step S7 in this invention. Detailed Implementation

[0022] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0023] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0024] like Figure 1 As shown, this embodiment provides a method for diagnosing thermal runaway in all-solid-state batteries based on displacement detection. This method utilizes displacement sensors configured on the all-solid-state battery cells to monitor in real-time the minute displacement changes generated by the expansion of the thermally expanding material layer, thereby achieving rapid diagnosis of thermal runaway states. Compared to traditional detection methods based on temperature or voltage sensors, this method directly captures the physical phenomena of the thermally expanding material's movement, significantly shortening the diagnostic response time and providing more timely fault warning signals for the battery management system.

[0025] Step S1: Obtain the structural configuration information of the all-solid-state battery cell. The all-solid-state battery cell includes a solid electrolyte layer, an electrode layer, and a thermal expansion material layer disposed between the solid electrolyte layer and the electrode layer. The thermal expansion material layer expands in volume when a preset trigger temperature is reached.

[0026] In this embodiment, it is first necessary to clarify the internal structural configuration of the all-solid-state battery cell. The all-solid-state battery cell adopts a stacked structure design, and its core components include a solid electrolyte layer and an electrode layer. The solid electrolyte layer, as the medium for lithium-ion conduction, undertakes the key function of transporting ions between the positive and negative electrodes. The electrode layer includes a positive electrode active material layer and a negative electrode active material layer, which are respectively disposed on both sides of the solid electrolyte layer.

[0027] In the technical solution of this invention, a thermally expanding material layer is disposed at the interface between the solid electrolyte layer and the electrode layer. This thermally expanding material layer has temperature response characteristics. When the local temperature inside the battery rises due to abnormal conditions (such as internal short circuit, overcharging, etc.) and reaches a preset trigger temperature, the thermally expanding particles in the thermally expanding material layer undergo a crystal structure transformation, causing significant volume expansion. This volume expansion generates mechanical stress on the adjacent solid electrolyte layer, thereby disrupting the ion conduction path and achieving active circuit breaking protection of the battery.

[0028] The specific process of obtaining structural configuration information includes: determining the specific location coordinates of the thermal expansion material layer within the battery cell, obtaining the thickness parameters of the thermal expansion material layer, and recording the relative positional relationship between the thermal expansion material layer, the solid electrolyte layer, and the electrode layer. This structural configuration information will provide a basis for selecting the placement location of the subsequent displacement sensor, ensuring that the sensor can effectively sense the deformation transmission generated when the thermal expansion material layer expands.

[0029] By clarifying the structural configuration information of the all-solid-state battery cell, the spatial distribution characteristics of the thermal expansion material layer can be accurately grasped, thereby allowing for the rational configuration of the displacement sensor installation position in subsequent steps, ensuring the effectiveness and sensitivity of displacement detection.

[0030] Step S2: A displacement sensor is disposed on the surface of the battery casing of the all-solid-state battery cell. The displacement sensor is mechanically coupled to the battery casing and is used to sense the deformation transmitted to the battery casing when the thermal expansion material layer expands.

[0031] After obtaining the structural configuration information of the all-solid-state battery cell, displacement sensors need to be installed at appropriate locations on the battery casing. The configuration of the displacement sensors is a key step in achieving rapid diagnosis of thermal runaway; their installation location and coupling method directly affect the sensitivity and reliability of the detection.

[0032] A robust mechanical coupling connection needs to be established between the displacement sensor and the battery casing. This mechanical coupling ensures that when the thermal expansion material layers inside the battery expand in volume, the resulting mechanical stress can be transmitted to the battery casing through the battery's internal layered structure, causing a minute deformation of the battery casing. The displacement sensor detects this minute deformation and converts the mechanical displacement into a measurable electrical signal.

[0033] In a preferred embodiment, the displacement sensor is a strain gauge, which is fixed to the surface of the battery casing by adhesive bonding. The detection sensitivity of the strain gauge is determined according to a preset expansion range of the thermal expansion material layer.

[0034] Specifically, a strain gauge is a precision sensor based on the resistance strain effect. When the surface of the object being measured deforms, the internal sensing grid of the strain gauge undergoes corresponding tensile or compressive deformation, resulting in a change in resistance. By measuring the change in resistance, the strain value and displacement of the measured surface can be calculated.

[0035] The strain gauges are installed using a specialized strain adhesive for bonding. Before bonding, the battery casing surface needs to be cleaned and sanded to remove oxide layers and contaminants, ensuring a tight bond between the strain gauge and the casing surface. After bonding, the strain gauge and battery casing form an integrated mechanical coupling structure, enabling synchronous sensing of minute deformations on the casing surface.

[0036] The detection sensitivity of the strain gauge needs to be selected based on the preset expansion range of the thermal expansion material layer. Since the expansion of the thermal expansion material layer at the trigger temperature is usually in the micrometer range, a highly sensitive strain gauge is required to ensure accurate capture of such minute displacement changes.

[0037] In another preferred embodiment, the displacement sensor is an optical fiber sensor, which is arranged along the surface of the battery casing, and the displacement detection signal is obtained by detecting the strain change of the optical fiber.

[0038] Fiber optic sensors are another alternative displacement detection solution. They utilize the wavelength shift characteristic of fiber Bragg gratings to sense strain changes. When the fiber deforms along with the battery casing, the period of the fiber Bragg grating changes accordingly, causing a wavelength shift in the reflected light. By detecting the amount of wavelength shift, the strain value on the casing surface can be calculated. Fiber optic sensors offer advantages such as strong resistance to electromagnetic interference and the ability to perform distributed measurements, making them suitable for applications with high electromagnetic compatibility requirements.

[0039] Furthermore, the displacement sensor is disposed on the battery casing in the region corresponding to the thermal expansion material layer, so that the displacement sensor can directly sense the displacement change on the deformation transmission path caused by the expansion of the thermal expansion material layer.

[0040] The selection of the installation location for the displacement sensor is crucial. Based on the structural configuration information obtained in step S1, the displacement sensor is positioned on the battery casing in the area corresponding to the location of the thermal expansion material layer. Since the mechanical stress generated by the expansion of the thermal expansion material layer is mainly transmitted along a direction perpendicular to the layer, placing the sensor directly above the deformation transmission path maximizes the detection of casing deformation caused by expansion and improves detection sensitivity.

[0041] By rationally configuring displacement sensors on the surface of the battery casing and establishing effective mechanical coupling connections, the internal physical phenomenon of volume expansion of the thermal expansion material layer can be transformed into a displacement signal that can be detected externally, laying the foundation for subsequent signal acquisition and processing.

[0042] Step S3: The deformation of the battery casing is monitored in real time by the displacement sensor, and the displacement of the battery casing caused by the expansion of the thermal expansion material layer is collected to obtain a displacement detection signal.

[0043] After the displacement sensor is configured, the real-time monitoring phase begins. The displacement sensor continuously monitors the deformation state of the battery casing. When the thermal expansion material layer expands in volume due to increased temperature, the mechanical stress generated by the expansion is transmitted outward through the internal layered structure of the battery, ultimately causing minute deformations on the surface of the battery casing. The displacement sensor senses this deformation in real time and converts it into a corresponding electrical signal output.

[0044] In the implementation using a strain gauge as a displacement sensor, the strain gauge's sensing grid deforms synchronously with the deformation of the battery casing surface, causing a change in the grid's resistance. This resistance change is detected using a Wheatstone bridge circuit, converting the minute change in resistance into a measurable voltage signal. This voltage signal is the original form of the displacement detection signal, and its amplitude corresponds to the deformation of the battery casing.

[0045] In implementations using fiber optic sensors, the fiber optic demodulator continuously monitors the reflected light wavelength of the fiber Bragg grating. When deformation of the battery casing causes strain in the fiber, the reflected light wavelength shifts accordingly. The fiber optic demodulator converts this wavelength shift into a digital signal output as a displacement detection signal.

[0046] The acquisition of displacement detection signals requires a sufficiently high sampling frequency to ensure timely capture of the rapidly changing physical process of thermal expansion of the material layer. The sampling frequency setting needs to comprehensively consider the response speed characteristics of the thermally expanding material and the real-time requirements of the system.

[0047] In a preferred embodiment, a plurality of displacement sensors are disposed on the surface of the battery casing, and each displacement sensor is distributed at a different position on the battery casing; in step S3, the displacement detection signal output by each displacement sensor is collected respectively.

[0048] To improve the reliability and coverage of detection, displacement sensors can be configured at multiple locations on the surface of the battery casing. This distributed arrangement of multiple sensors allows for the detection of the battery casing's deformation from different angles. Even if one sensor experiences signal abnormalities due to installation misalignment or localized interference, other sensors can still provide effective detection signals, thereby improving system redundancy and reliability.

[0049] In a multi-sensor configuration, each sensor independently detects displacement and outputs its own displacement detection signal. The signal acquisition module synchronously acquires the output signals from each sensor, forming multi-channel displacement detection data.

[0050] By monitoring and acquiring displacement detection signals in real time, the physical phenomenon of thermal expansion of the material layer inside the battery can be converted into an analyzable electrical signal in a timely manner. Compared with traditional temperature detection methods, this method of directly detecting physical actions has a shorter response delay and can issue early warnings at a more early stage of thermal runaway development.

[0051] Step S4: Perform signal conditioning processing on the displacement detection signal, including filtering and amplification, to obtain the processed displacement signal value.

[0052] The raw displacement detection signal output by a displacement sensor typically contains various noise and interference components, and the signal amplitude is relatively small. Therefore, signal conditioning processing is required to extract effective displacement information. Signal conditioning processing mainly includes two stages: filtering and amplification.

[0053] The purpose of filtering is to remove noise components from the displacement detection signal. In practical applications, the displacement detection signal may be affected by various factors such as power supply ripple, electromagnetic interference, and mechanical vibration. These interferences can introduce high-frequency noise or low-frequency drift into the signal. A bandpass filter is used to filter the original signal, retaining the signal components that match the expansion response frequency of the thermally expanding material layer, while suppressing noise interference outside this frequency band. The cutoff frequency of the filter is set according to the response characteristics of the thermally expanding material and the actual noise spectrum distribution.

[0054] The purpose of amplification is to amplify the weak displacement detection signal to an amplitude range suitable for subsequent processing. Since the deformation of the battery casing caused by the expansion of the thermal expansion material layer is typically on the order of micrometers, the original signal amplitude output by the displacement sensor is relatively small. By amplifying the filtered signal through a signal amplification circuit, the signal amplitude is increased to the optimal input range of the analog-to-digital converter (ADC), thus fully utilizing the ADC's resolution and improving the signal quantization accuracy.

[0055] Furthermore, in this embodiment of the application, the signal conditioning process in step S4 further includes temperature compensation processing, specifically: obtaining the current temperature value of the environment where the displacement sensor is located; compensating and correcting the displacement detection signal according to the current temperature value and a preset temperature compensation coefficient; filtering and amplifying the compensated and corrected signal to obtain the processed displacement signal value.

[0056] In practical applications, the output characteristics of displacement sensors (especially strain gauges) are affected by changes in ambient temperature. When the ambient temperature changes, the sensitive grid material of the strain gauge will generate additional resistance changes due to thermal expansion and contraction. This temperature-induced resistance change is superimposed on the resistance change caused by the measured deformation, leading to measurement errors.

[0057] To eliminate the influence of ambient temperature changes on the measurement results, temperature compensation is introduced during signal conditioning. First, the current ambient temperature is acquired using a temperature sensing element positioned near the sensor. Then, based on a pre-calibrated temperature compensation coefficient, the temperature drift of the strain gauge at the current temperature is calculated, and this drift is subtracted from the original displacement detection signal to obtain the compensated signal. The temperature compensation coefficient is determined through sensor temperature characteristic calibration experiments and reflects the output signal drift caused by a unit temperature change.

[0058] After filtering, amplification, and temperature compensation, the processed displacement signal value is obtained. This signal value accurately reflects the actual displacement of the battery casing caused by the expansion of the thermal expansion material layer, providing a reliable data basis for subsequent threshold determination.

[0059] By performing systematic signal conditioning on the displacement detection signal, useful signals can be effectively extracted, noise interference can be suppressed, and the effects of temperature drift can be eliminated, thereby improving the accuracy and stability of displacement detection and reducing the risk of false alarms and missed alarms.

[0060] Step S5: Compare the processed displacement signal value with a preset displacement threshold. When the processed displacement signal value is greater than or equal to the preset displacement threshold, generate a thermal runaway trigger signal.

[0061] After obtaining the processed displacement signal value, a threshold judgment needs to be performed to determine whether the thermal expansion material layer has expanded. The processed displacement signal value is compared with a preset displacement threshold in real time. When the displacement signal value reaches or exceeds the preset displacement threshold, it is determined that the thermal expansion material layer has expanded and the battery cell has entered a thermal runaway state. At this time, a thermal runaway trigger signal is generated.

[0062] Setting the preset displacement threshold is a key parameter for balancing detection sensitivity and false alarm resistance. If the threshold is set too low, minor vibrations or noises under normal operating conditions may be misinterpreted as thermal runaway signals, resulting in false alarms; if the threshold is set too high, it may delay the response to real thermal runaway events, reducing the timeliness of protection.

[0063] In a preferred embodiment, the preset displacement threshold is determined based on the following parameters: obtaining the expansion coefficient of the thermal expansion material layer; obtaining the stiffness parameter of the battery casing; calculating the theoretical displacement amount transmitted to the battery casing when the thermal expansion material layer expands at the preset trigger temperature based on the expansion coefficient and the stiffness parameter; and multiplying the theoretical displacement amount by a preset safety factor to obtain the preset displacement threshold.

[0064] The process for determining the preset displacement threshold is as follows: First, obtain the expansion coefficient of the thermal expansion material layer, which characterizes the proportion of volume expansion of the thermal expansion material when it reaches the trigger temperature. Second, obtain the stiffness parameter of the battery casing, which reflects the battery casing's ability to resist deformation; the greater the stiffness, the smaller the deformation of the casing caused by the same internal expansion force.

[0065] Based on the above parameters, the theoretical displacement transmitted to the battery casing when the thermal expansion material layer expands at a preset trigger temperature can be calculated. The calculation of the theoretical displacement needs to consider factors such as the thickness of the thermal expansion material layer, its expansion coefficient, the mechanical transmission characteristics of each layer inside the battery, and the stiffness of the battery casing. Through finite element analysis or a simplified mechanical model, a mapping relationship between the internal expansion and the surface displacement of the casing can be established.

[0066] To ensure the reliability of the detection and to allow for a certain safety margin, the theoretical displacement is multiplied by a preset safety factor to obtain the final preset displacement threshold. The preset safety factor is less than 1, so that the actual trigger threshold is lower than the theoretical displacement, thus triggering an early warning before the thermal expansion material layer has fully expanded, improving the timeliness of protection.

[0067] In the case of configuring multiple displacement sensors, in step S5, when the processed displacement signal value corresponding to any one of the displacement sensors is greater than or equal to the preset displacement threshold, the thermal runaway action trigger signal is generated.

[0068] In the multi-sensor configuration, each sensor independently determines the threshold. An OR logic is used for comprehensive judgment; that is, if the displacement signal value of any one sensor reaches a preset threshold, a thermal runaway trigger signal is generated. This judgment logic ensures that even if the expansion of the thermal expansion material layer occurs in a localized area, it can be detected promptly by sensors near that area.

[0069] Furthermore, in the embodiments of this application, such as Figure 2 As shown, step S5 further includes: performing a comprehensive analysis on the processed displacement signal values ​​corresponding to each displacement sensor; determining the location region where the thermal expansion material layer expands based on the distribution characteristics of each processed displacement signal value; and transmitting the location region information and the thermal runaway trigger signal together to the battery management system.

[0070] Besides determining whether thermal runaway has occurred, the signal distribution characteristics of multiple sensors can be used to analyze the location of the expansion. Since the sensors are distributed at different locations on the battery casing, sensors closer to the expansion area will detect larger displacement signals, while sensors farther away will detect relatively smaller displacement signals. By analyzing the relative magnitude and distribution patterns of the sensor signal values, the approximate location of the thermal expansion material layer can be inferred.

[0071] Outputting the expansion location information along with the thermal runaway trigger signal can provide the battery management system with richer diagnostic information, which is helpful for subsequent fault analysis and maintenance decisions.

[0072] By comparing displacement thresholds, continuously changing displacement signal values ​​can be transformed into clear thermal runaway state determination results, providing a trigger basis for the subsequent response of the battery management system.

[0073] Step S6: The thermal runaway trigger signal and the identification information of the all-solid-state battery cell are transmitted to the battery management system, which then determines the location of the faulty battery cell that has experienced thermal runaway based on the identification information.

[0074] Once a thermal runaway trigger signal is generated, the signal and related information must be promptly transmitted to the battery management system (BMS) so that the BMS can take appropriate protective measures. The transmitted information includes the thermal runaway trigger signal itself and the identification information of the all-solid-state battery cell that generated the signal.

[0075] The identification information for an all-solid-state battery cell is a unique identifier pre-assigned to each cell, used to distinguish different cells within a battery module or pack. This identification information may include the cell's number, its location coordinates within the module, and the series or parallel branch it belongs to.

[0076] Signal transmission can be implemented using wired or wireless methods. In wired transmission, the displacement detection circuit of each battery cell is connected to the battery management system via a communication bus, exchanging data using a standard communication protocol. In wireless transmission, each battery cell is equipped with a wireless communication module, which wirelessly transmits trigger signals and identification information to the receiving end of the battery management system.

[0077] Upon receiving a thermal runaway trigger signal, the battery management system (BMS) queries its maintained battery cell mapping table based on the accompanying identification information to determine the specific location of the faulty battery cell within the entire battery system. Location information includes the module number where the faulty cell resides, its position within the module, and its connection relationship in the electrical topology.

[0078] For a battery module containing multiple all-solid-state battery cells, a displacement sensor is configured on each all-solid-state battery cell, and each displacement sensor independently executes steps S3 to S5; the battery management system receives the thermal runaway action trigger signal corresponding to each all-solid-state battery cell, and determines the thermal runaway state of each all-solid-state battery cell according to the identification information.

[0079] In practical applications, battery modules are typically composed of multiple all-solid-state battery cells connected in series or parallel. To achieve comprehensive monitoring of the entire battery module, a displacement sensor is configured on each battery cell, and each sensor independently completes the acquisition, processing, and threshold determination of displacement signals. The battery management system aggregates and receives the monitoring results from each battery cell, tracks the status of each battery cell according to its identification information, and realizes distributed monitoring and centralized management of the entire battery module.

[0080] The advantages of this distributed monitoring architecture are: the monitoring of each battery cell is independent of each other, and the sensor failure of one cell will not affect the monitoring function of other cells; the battery management system can accurately locate the specific cell where thermal runaway occurs, providing accurate target information for subsequent isolation protection and fault handling.

[0081] By transmitting trigger signals and identification information to the battery management system, and then having the battery management system locate the faulty unit, information transmission from unit-level monitoring to system-level management is realized, laying an information foundation for the safety protection of the battery system.

[0082] Furthermore, in a preferred embodiment, such as Figure 3 As shown, the method further includes step S7: Step S701: After generating the thermal runaway trigger signal, continuously monitor the change trend of the processed displacement signal value within a preset time window; Step S702: When the processed displacement signal value remains above the preset displacement threshold within the preset time window, the thermal runaway trigger signal is confirmed to be valid. Step S703: Transmit the confirmed valid thermal runaway trigger signal to the battery management system.

[0083] To further improve diagnostic accuracy and avoid false triggering due to transient interference, a diagnostic confirmation mechanism is introduced after generating the thermal runaway trigger signal. This mechanism performs secondary confirmation of the trigger signal's validity by continuously monitoring the changing trend of the displacement signal value within a preset time window.

[0084] like Figure 4As shown, specifically, when the displacement signal value first reaches the preset displacement threshold, the system initially generates a thermal runaway trigger signal and simultaneously initiates a diagnostic confirmation procedure. Within the subsequent preset time window, the system continuously monitors changes in the displacement signal value. If the displacement signal value remains above the preset displacement threshold throughout the entire time window, it indicates that the thermal expansion material layer has indeed undergone continuous expansion. At this point, the thermal runaway trigger signal is confirmed as valid and transmitted to the battery management system.

[0085] Conversely, if the displacement signal value falls below the preset displacement threshold within the time window, it indicates that the initial trigger may be a false trigger caused by transient vibration or noise pulse. In this case, the trigger signal is canceled and not sent to the battery management system.

[0086] The length of the preset time window needs to comprehensively consider the response characteristics of the thermally expanding material and the system's response time requirements. A time window that is too short may fail to effectively distinguish between a real trigger and a transient disturbance; a time window that is too long will delay the response to a real thermal runaway event. Based on the time characteristics of the thermally expanding material layer's expansion process, a reasonable time window length should be set to ensure both diagnostic accuracy and timely response.

[0087] By introducing a diagnostic confirmation mechanism, false triggers caused by transient interference can be effectively filtered out, improving the reliability of thermal runaway diagnosis, reducing unnecessary system protection actions, and ensuring timely response to real thermal runaway events.

[0088] The displacement detection-based thermal runaway diagnosis method for all-solid-state batteries provided in this embodiment directly detects the minute displacement changes generated during the expansion of the thermally expanding material layer. Compared with traditional detection methods based on temperature or voltage, this method enables a faster diagnostic response. Since displacement detection directly captures the physical phenomenon of the thermally expanding material's movement, rather than indirect characteristics of the thermal runaway development process such as temperature increases or voltage anomalies, it can issue early warnings at a more advanced stage of thermal runaway development. This provides the battery management system with more response time, thereby more effectively preventing the expansion and spread of thermal runaway accidents.

[0089] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0090] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0091] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0092] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0093] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for diagnosing thermal runaway in all-solid-state batteries based on displacement detection, characterized in that, Includes the following steps: S1: Obtain the structural configuration information of the all-solid-state battery cell, which includes a solid electrolyte layer, an electrode layer, and a thermal expansion material layer disposed between the solid electrolyte layer and the electrode layer. The thermal expansion material layer expands in volume when a preset trigger temperature is reached. S2: A displacement sensor is disposed on the surface of the battery casing of the all-solid-state battery cell. The displacement sensor is mechanically coupled to the battery casing and is used to sense the deformation transmitted to the battery casing when the thermal expansion material layer expands. S3: The deformation of the battery casing is monitored in real time by the displacement sensor, and the displacement of the battery casing caused by the expansion of the thermal expansion material layer is collected to obtain a displacement detection signal; S4: Perform signal conditioning processing on the displacement detection signal, including filtering and amplification, to obtain the processed displacement signal value; S5: Compare the processed displacement signal value with a preset displacement threshold. When the processed displacement signal value is greater than or equal to the preset displacement threshold, generate a thermal runaway trigger signal. S6: The thermal runaway trigger signal and the identification information of the all-solid-state battery cell are transmitted to the battery management system, which then determines the location of the faulty battery cell that has experienced thermal runaway based on the identification information.

2. The method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 1, characterized in that, The displacement sensor is a strain gauge, which is fixed to the surface of the battery casing by adhesive bonding. The detection sensitivity of the strain gauge is determined according to the preset expansion range of the thermal expansion material layer.

3. The method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 1, characterized in that, The displacement sensor is an optical fiber sensor, which is arranged along the surface of the battery casing. The displacement detection signal is obtained by detecting the strain change of the optical fiber.

4. A method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 2 or 3, characterized in that, The displacement sensor is disposed on the battery casing in the area corresponding to the thermal expansion material layer, so that the displacement sensor can directly sense the displacement change on the deformation transmission path caused by the expansion of the thermal expansion material layer.

5. The method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 1, characterized in that, The preset displacement threshold is determined based on the following parameters: obtaining the expansion coefficient of the thermal expansion material layer; obtaining the stiffness parameter of the battery casing; and calculating the theoretical displacement transmitted to the battery casing when the thermal expansion material layer expands at the preset trigger temperature based on the expansion coefficient and the stiffness parameter. The theoretical displacement is multiplied by a preset safety factor to obtain the preset displacement threshold.

6. The method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 1, characterized in that, The signal conditioning process in step S4 also includes temperature compensation processing, specifically: obtaining the current temperature value of the environment where the displacement sensor is located; compensating and correcting the displacement detection signal according to the current temperature value and a preset temperature compensation coefficient; filtering and amplifying the compensated and corrected signal to obtain the processed displacement signal value.

7. The method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 1, characterized in that, Multiple displacement sensors are configured on the surface of the battery casing, and each displacement sensor is distributed at a different position on the battery casing; in step S3, the displacement detection signals output by each displacement sensor are collected respectively; in step S5, when the processed displacement signal value corresponding to any displacement sensor is greater than or equal to the preset displacement threshold, a thermal runaway trigger signal is generated.

8. The method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 7, characterized in that, Step S5 further includes: performing a comprehensive analysis on the processed displacement signal values ​​corresponding to each displacement sensor; determining the location region where the thermal expansion material layer expands based on the distribution characteristics of each processed displacement signal value; and transmitting the location region and the thermal runaway trigger signal together to the battery management system.

9. The method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 1, characterized in that, For a battery module containing multiple all-solid-state battery cells, a displacement sensor is configured on each all-solid-state battery cell, and each displacement sensor independently executes steps S3 to S5; the battery management system receives the thermal runaway action trigger signal corresponding to each all-solid-state battery cell, and determines the thermal runaway state of each all-solid-state battery cell according to the identification information.

10. A method for diagnosing thermal runaway of an all-solid-state battery based on displacement detection according to claim 9, characterized in that, It also includes a diagnostic confirmation step: after generating the thermal runaway trigger signal, continuously monitor the change trend of the processed displacement signal value within a preset time window; when the processed displacement signal value remains above the preset displacement threshold within the preset time window, confirm that the thermal runaway trigger signal is valid; and transmit the confirmed valid thermal runaway trigger signal to the battery management system.

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