A power battery thermal runaway monitoring device

Abstract

The application relates to the technical field of battery thermal monitoring, and discloses a power battery thermal runaway monitoring device, a plurality of battery cells are arranged in a power battery, the device comprises a plurality of flexible pressure sensors, the plurality of flexible pressure sensors are connected in series, the flexible pressure sensors are arranged between two adjacent battery cells and are attached to the side walls of the battery cells, an elastic gasket is arranged between the pressure sensors and the side walls of the battery cells, and a monitoring module is connected with the pressure sensors through connecting lines. The flexible pressure sensor is a continuous circuit, can directly and accurately detect the overall deformation variable, and can buffer and conduct the deformation when the deformation amplitude of the battery cell is large in cooperation with the elastic gasket, so that the attached area of the flexible pressure sensor is ensured, the coverage rate of the flexible pressure sensor is improved, and the overall deformation variable of the battery cell can be quickly and accurately detected when the deformation amplitude is large.

Description

Technical Field

[0001] This application relates to the technical field of battery thermal monitoring, and in particular to a power battery thermal runaway monitoring device. Background Technology

[0002] During the charge-discharge cycle of a power battery, especially under extreme operating conditions, a large amount of heat can easily accumulate inside the battery. If this heat is not effectively dissipated, the battery temperature will rise sharply, inducing abnormal chemical reactions inside the cell, accompanied by gas generation, causing the cell volume to expand, and ultimately triggering the opening of the pressure relief valve to release pressure. Although the battery management system (BMS) continuously monitors the cell temperature, voltage, and the presence of smoke inside the battery pack to assess whether the cell is in a state of thermal runaway, this monitoring mechanism still has a certain lag in responding to emergencies.

[0003] Chinese patent application CN202411474880.6, published on February 7, 2025, discloses a battery module and a pressure testing method for the battery module, comprising: a pressure sensor, an integrated busbar, and a cell module. The cell module includes multiple stacked cells and an end plate disposed at the outermost cell. The pressure sensor is sandwiched between two adjacent cells and is electrically connected to the integrated busbar. The integrated busbar covers the side of the cell with the terminal post. The pressure sensor is an array-type thin-film pressure sensor or a single-point thin-film pressure sensor.

[0004] In implementing the above solution, the applicant discovered the following problems: Whether it is an array-type thin-film pressure sensor or a single-point thin-film pressure sensor, the sensor sensing unit is used to independently detect the local pressure on the sidewall of the battery cell, which is suitable for static pressure detection. In dynamic pressure detection when the battery cell deforms, the local pressure detection and its own limited flexibility are not conducive to detecting the overall deformation of the sidewall of the battery cell. Moreover, when the sensing units in the array-type thin-film pressure sensor are integrated at high density, signal crosstalk will also be generated, resulting in low pressure detection accuracy. This makes it impossible to determine in a timely and accurate manner whether the battery cell is in a thermal runaway state, and there is still a certain lag in responding to emergencies. Utility Model Content

[0005] 1. The problem to be solved

[0006] Therefore, it is necessary to provide a power battery thermal runaway monitoring device that can directly and accurately detect the overall deformation of the cell sidewall, addressing the aforementioned technical problems.

[0007] 2. Technical Solution

[0008] This application provides a power battery thermal runaway monitoring device. The power battery contains multiple cells. The device includes: multiple flexible pressure sensors connected in series, with the flexible pressure sensors disposed between two adjacent cells and attached to the side wall of the cell; an elastic gasket disposed between the pressure sensor and the side wall of the cell; and a monitoring module connected to the pressure sensor via a connecting wire.

[0009] The flexible pressure sensor is a continuous circuit that can directly and accurately detect the overall deformation. When used with an elastic pad, it can buffer and transmit deformation when the deformation of the battery cell is large, ensuring the contact area of ​​the flexible pressure sensor and improving its coverage. This helps to quickly and accurately detect the overall topographical changes of the battery cell when there is a large deformation.

[0010] In one embodiment, the flexible pressure sensor is made of liquid metal printed circuit. When the liquid metal is combined with a flexible substrate (such as PDMS or fabric), it can withstand large deformations and avoid circuit breakage or performance degradation due to bending.

[0011] In one embodiment, the liquid metal includes a gallium-indium alloy. The high conductivity of the gallium-indium alloy (3.40 × 10⁴ S·cm⁻¹) combined with the micron-scale electrode structure enables a detection limit as low as 1.84 Pa and a millisecond-level response, meeting the requirements for dynamic pressure monitoring.

[0012] In one embodiment, the flexible pressure sensor is less than 0.5 mm thick. Its ultra-thin design allows it to fit tightly against the surface of the battery cell sidewall and the surface of the elastic pad, measuring the overall deformation of the battery cell sidewall.

[0013] In one embodiment, the flexible pressure sensor has a coverage area greater than or equal to 80% of the cell sidewall, which enables accurate and sensitive detection of the overall deformation of the cell with a large coverage area.

[0014] In one embodiment, the elastic gasket is a silicone gasket with a Shore hardness of 35±5, a compression set of <10% (ASTM D395 standard), and maintains elastic modulus stability (change rate <15%) within the operating range of -40℃ to 150℃.

[0015] In one embodiment, the surface of the silicone pad is provided with a bump array, which can ensure a large effective contact area when the battery cell deforms, thereby improving the accuracy and sensitivity of the detection.

[0016] In one embodiment, the surface of the connecting wire is provided with a multi-layer composite protective sleeve to insulate against heat and ensure that the connecting wire is not damaged by heat.

[0017] In one embodiment, the device further includes a constant power module connected to the monitoring module for continuously supplying power to the monitoring module independently.

[0018] In one embodiment, the device further includes: a battery management system connected to the monitoring module; and other electronic control units connected to the monitoring module.

[0019] 3. Beneficial effects

[0020] The method described above, employed in this application, has the following beneficial technical effects:

[0021] 1. The elastic pad can buffer and transmit deformation when the cell deformation is large, ensuring the contact area of ​​the flexible pressure sensor and improving the coverage of the flexible pressure sensor, thus helping to quickly and accurately detect the overall topographic variables of the cell when there is a large deformation.

[0022] 2. During the daily operation of the battery cell, the small deformations generated by charging and discharging are absorbed by the flexible pressure sensor; when the battery cell undergoes thermal expansion deformation, the deformation amplitude is larger, and it is buffered and transmitted by the elastic pad; when the pressure sensor detects an abnormality, that is, when the deformation exceeds the set value, it indicates that an abnormality has occurred, triggering emergency braking and alarm, thus forming a graded early warning mechanism based on the deformation.

[0023] 3. By setting a bump array on the surface of the elastic gasket, the coverage area of ​​the flexible pressure sensor can be effectively guaranteed when the battery cell undergoes large deformation, thereby improving the overall detection accuracy.

[0024] 4. A constant power module is provided to ensure that the monitoring module is continuously powered by the vehicle under any condition, enabling uninterrupted monitoring of the battery cells. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of a power battery thermal runaway monitoring device in one embodiment;

[0026] Figure 2 This is a structural diagram illustrating the positional relationship between the battery cell, flexible pressure sensor, and elastic gasket in one embodiment.

[0027] Figure 3 This is a schematic diagram of the system environment of a power battery thermal runaway monitoring device in one embodiment.

[0028] Reference numerals: 1. Battery cell; 2. Connecting wire; 3. Flexible pressure sensor; 4. Constant power module; 5. Elastic gasket; 6. Monitoring module; 7. Battery management system; 8. Other electronic control units. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0030] Reference Figure 1 and Figure 2 This application provides a power battery thermal runaway monitoring device. The power battery contains multiple cells 1. The device includes: multiple flexible pressure sensors 3 connected in series, with each flexible pressure sensor 3 disposed between two adjacent cells 1 and attached to the side wall of the cell 1; an elastic gasket 5 disposed between the pressure sensor and the side wall of the cell 1; and a monitoring module 6 connected to the pressure sensor via a connecting line 2.

[0031] The elastic pad 5 can buffer and transmit deformation when the deformation of the battery cell 1 is large, ensuring the contact area of ​​the flexible pressure sensor 3 and improving the coverage of the flexible pressure sensor 3, thereby helping to quickly and accurately detect the overall terrain variables of the battery cell 1.

[0032] The flexible pressure sensor 3 is a continuous circuit that can directly and accurately detect overall deformation. By attaching the flexible pressure sensor 3 to the sidewall of a battery cell 1, such as between two battery cells 1, seamless monitoring of the battery cell 1's status can be achieved. Furthermore, because the pressure sensors are connected in series, even if only a very small number of battery cells 1 experience anomalies, changes in the volume of the battery cell 1 can be quickly detected, and a clear abnormality signal can be output to the monitoring module 6, triggering a chain reaction.

[0033] During the daily operation of the battery cell 1, the small deformations generated by the charging and discharging of the battery cell 1 are absorbed by the flexible pressure sensor 3; when the battery cell 1 undergoes thermal expansion deformation, the deformation amplitude is larger, and it is buffered and conducted by the elastic pad 5; when the pressure sensor detects an abnormality, that is, when the deformation exceeds the set value, it indicates that an abnormality has occurred, triggering emergency braking and alarm, thereby forming a graded early warning mechanism based on the deformation.

[0034] In one embodiment, the flexible pressure sensor 3 is made of liquid metal printed circuit. After the liquid metal is combined with a flexible substrate (such as PDMS or fabric), it can withstand large deformations and avoid circuit breakage or performance degradation due to bending.

[0035] In one embodiment, the liquid metal includes a gallium-indium alloy. The high conductivity of the gallium-indium alloy (3.40 × 10⁴ S·cm⁻¹) combined with the micron-scale electrode structure enables a detection limit as low as 1.84 Pa and a millisecond-level response, meeting the requirements for dynamic pressure monitoring.

[0036] In one embodiment, the flexible pressure sensor 3 is less than 0.5 mm thick. Its ultra-thin design allows it to fit tightly against the sidewall surface of the battery cell 1 and the surface of the elastic pad 5, measuring the overall deformation of the sidewall of the battery cell 1.

[0037] In one embodiment, the flexible pressure sensor 3 has a coverage area greater than or equal to 80% of the sidewall of the battery cell 1. With a large coverage area, it can accurately and sensitively detect the overall deformation of the battery cell 1.

[0038] In one embodiment, the elastic gasket 5 is a silicone gasket with a Shore hardness of 35±5, and its compression set is <10% (ASTM D395 standard), maintaining elastic modulus stability (change rate <15%) within the working range of -40℃ to 150℃.

[0039] In one embodiment, the surface of the silicone pad is provided with an array of bumps.

[0040] Specifically, the diameter of the protrusions is 0.2 mm, the height is 0.1 mm, and the spacing between the protrusions is 0.5 mm. This allows for an effective contact area of ​​>85% under a 3N preload, thereby improving the accuracy and sensitivity of the detection.

[0041] In one embodiment, the combination design of the elastic pad 5 and the flexible patch of the above specifications enables the sensor network to have a three-level deformation compensation capability: ① 0.1-0.5mm of daily charging and discharging deformation is absorbed by the pressure sensor (liquid metal circuit); ② 0.5-2mm of thermal expansion deformation is buffered and conducted through the elastic pad 5; ③ >2mm of abnormal deformation triggers emergency braking, forming a graded early warning mechanism.

[0042] In one embodiment, the surface of the connecting wire 2 is provided with a multi-layer composite protective sleeve to insulate heat and ensure that the connecting wire 2 is not damaged by heat.

[0043] Specifically, the inner layer of the multi-layer composite protective sleeve is a high-temperature resistant polyimide insulating layer (withstanding 200℃ / 500h), the middle layer is an aluminum-magnesium alloy electromagnetic shielding layer, and the outer layer is a fluororubber anti-corrosion coating layer. The bending radius of the protective sleeve can reach 5mm, adapting to the complex wiring requirements inside the battery pack.

[0044] Reference Figure 3 In one embodiment, the device further includes a constant power module 4, connected to the monitoring module 6, for continuously supplying power to the monitoring module 6 independently.

[0045] As a unique power supply unit, the constant power module 4 ensures continuous power supply to the vehicle in any state (whether it is running, stationary, or in hibernation). The all-weather power supply characteristic of the constant power module 4 enables the monitoring module 6 to continuously monitor the thermal runaway of the power battery even when the battery management system 7 is in hibernation or the vehicle is stopped.

[0046] Reference Figure 3 In one embodiment, the device further includes: a battery management system 7 connected to the monitoring module 6; and other electronic control units 8 connected to the monitoring module 6.

[0047] The monitoring module 6 is not only tightly integrated with the battery management system 7, but also realizes data transmission with one or more key electronic control units pre-designated in the vehicle through wiring harness, thereby building an information-sharing monitoring network and enhancing the comprehensiveness and accuracy of overall monitoring and control.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A power battery thermal runaway monitoring device, wherein the power battery contains multiple cells, characterized in that, The device includes: Multiple flexible pressure sensors are connected in series, and the flexible pressure sensors are placed between two adjacent cells and attached to the side wall of the cell. An elastic gasket is placed between the pressure sensor and the side wall of the battery cell; The monitoring module is connected to the pressure sensor via a connecting cable.

2. The power battery thermal runaway monitoring device according to claim 1, characterized in that, The flexible pressure sensor is made of liquid metal printed circuitry.

3. The power battery thermal runaway monitoring device according to claim 2, characterized in that, Liquid metals include gallium-indium alloys.

4. The power battery thermal runaway monitoring device according to claim 1, characterized in that, The thickness of the flexible pressure sensor is less than 0.5 mm.

5. The power battery thermal runaway monitoring device according to claim 1, characterized in that, The coverage area of ​​the flexible pressure sensor is greater than or equal to 80% of the cell sidewall.

6. The power battery thermal runaway monitoring device according to claim 1, characterized in that, The elastic gasket is a silicone gasket with a Shore hardness of 35±5.

7. The power battery thermal runaway monitoring device according to claim 1, characterized in that, The surface of the silicone pad has an array of bumps.

8. The power battery thermal runaway monitoring device according to claim 1, characterized in that, The surface of the connecting cable is covered with a multi-layer composite protective sleeve.

9. The power battery thermal runaway monitoring device according to claim 1, characterized in that, Also includes: The constant power module is connected to the monitoring module and is used to provide continuous power to the monitoring module independently.

10. The power battery thermal runaway monitoring device according to claim 1, characterized in that, Also includes: Battery management system, connected to the monitoring module; Other electronic control units are connected to the monitoring module.

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