Battery pack thermal runaway alarm fire extinguishing device and method based on laser monitoring infrared positioning

Abstract

The application relates to the technical field of battery safety monitoring and fire control, and discloses a battery pack thermal runaway alarm and fire extinguishing device and method based on laser monitoring and infrared positioning, which comprises a battery box, a laser monitoring mechanism, an infrared positioning and fire extinguishing mechanism, a multi-axis motion mechanism and an integrated control unit. A plurality of lithium battery monomers are distributed in the battery box. The laser monitoring mechanism comprises a plurality of reflectors, a signal processing unit, a laser emitter and a laser receiver. The laser emitter and the laser receiver are arranged in the battery box. The light beams emitted by the laser emitter pass through the plurality of reflectors to form a continuous light path that sequentially passes through the lithium battery monomers. The infrared positioning and fire extinguishing mechanism comprises a fire extinguisher and an infrared detector. The output end of the fire extinguisher and the infrared detector are arranged in the battery box above the lithium battery monomers through the multi-axis motion mechanism. The application realizes early warning and blind area-free monitoring of battery thermal runaway, and realizes accurate positioning and directional disposal of the fault battery.

Description

Technical Field

[0001] This invention relates to the field of battery safety monitoring and fire control technology, specifically to a battery pack thermal runaway alarm and extinguishing device and method based on laser monitoring and infrared positioning. Background Technology

[0002] With the rapid development of electric vehicles and large-scale energy storage power stations, lithium batteries have been widely used due to their high energy density and good cycle performance. However, lithium batteries are prone to thermal runaway under abnormal operating conditions such as overcharging, short circuits, or mechanical damage. Thermal runaway is typically characterized by single-point triggering and rapid propagation. If it is not detected and effectively handled in time, it can easily lead to fires or even explosions, causing serious casualties and economic losses. Therefore, early monitoring and effective handling of battery thermal runaway are of great significance.

[0003] In existing technologies, monitoring of battery thermal runaway typically employs a combination of discretely arranged point temperature sensors and gas sensors. In this approach, multiple temperature sensors are arranged at certain intervals inside the battery, while a small number of gas sensors are placed on the common gas ducts of the battery pack to monitor the battery's operating status.

[0004] However, the above monitoring methods still have the following shortcomings: First, because the sensors are discretely arranged, it is difficult to cover all individual cells in the battery pack, which can easily create monitoring blind spots; when a battery cell generates a small amount of heat or smoke in the early stage of thermal runaway, it takes a certain amount of time for the heat conduction or gas diffusion process to be detected by the sensor, resulting in a significant lag in system response and making it difficult to provide timely early warning; second, when a sensor triggers an alarm, it can only indicate that there is an anomaly in its vicinity, making it difficult to accurately locate the specific battery cell that has experienced thermal runaway.

[0005] Regarding fire extinguishing devices, existing systems mostly employ total flooding or fixed-zone spray structures. The nozzle installation positions and spray directions are typically fixed, making it difficult to adjust the extinguishing range according to the actual location of the fault. This approach not only results in significant consumption of extinguishing agents but may also cause secondary effects such as soaking, overcooling, or deterioration of insulation performance of batteries and related electrical equipment that are not currently malfunctioning. Furthermore, existing fire extinguishing systems generally lack real-time feedback and dynamic adjustment capabilities to changes in the fire situation, making it difficult to accurately address fault points.

[0006] Therefore, there is an urgent need for an early warning and handling technology solution that can achieve blind-spot-free monitoring, rapid response, and precise positioning of battery thermal runaway, as well as directional fire suppression and feedback control capabilities, so as to prevent the spread of thermal runaway at its source and improve the overall safety and reliability of the battery system. Summary of the Invention

[0007] To address the problems existing in the background technology, this invention proposes a battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning. The device includes a battery box, a laser monitoring mechanism, an infrared positioning and fire extinguishing mechanism, a multi-axis motion mechanism, and an integrated control unit. The battery box contains multiple lithium battery cells arranged in a rectangular array. The laser monitoring mechanism includes multiple reflectors, a signal processing unit, a laser emitter, and a laser receiver. The laser emitter and receiver are respectively located on opposite sides inside the battery box, above two diagonally positioned lithium battery cells. The laser receiver receives the laser beam emitted by the laser emitter through multiple reflectors, forming a continuous optical path that passes sequentially through each lithium battery cell. The infrared positioning and fire extinguishing mechanism includes a fire extinguisher and an infrared detector. The output end of the fire extinguisher and the infrared detector are movably mounted inside the battery box and above the lithium battery cells via the multi-axis motion mechanism. The integrated control unit is connected to the infrared detector, the signal processing unit, the multi-axis motion mechanism, and the fire extinguisher. The signal processing unit is connected to the laser receiver.

[0008] Preferably, the multi-axis motion mechanism includes two X-axis guide rails and one Y-axis guide rail. The two X-axis guide rails are respectively located on opposite sides inside the battery box. X-axis sliders are slidably mounted on the X-axis guide rails, and the two ends of the Y-axis guide rail are respectively connected to the two X-axis sliders.

[0009] Preferably, the fire extinguisher includes an extinguishing agent container and an extinguishing nozzle. The outlet of the extinguishing agent container is connected to the extinguishing nozzle via a telescopic pipe. A Y-axis slider is slidably mounted on the Y-axis guide rail. The extinguishing nozzle and an infrared detector are mounted on the Y-axis slider. A solenoid valve is provided at the outlet of the extinguishing agent container, and the solenoid valve is connected to an integrated control unit.

[0010] Preferably, the telescopic conduit is a corrugated pressure-resistant flexible hose.

[0011] Preferably, the fire extinguishing nozzle and the infrared detector are arranged side by side along the Y direction.

[0012] Preferably, the center distance between the fire extinguishing nozzle and the infrared detector is 40 mm, the X-guide rail is installed at a height of 300 mm from the bottom surface of the battery box, the laser receiver and laser emitter are installed at a height of 200 mm from the bottom surface of the battery box, the fire extinguishing agent container outlet is 350 mm from the bottom surface of the battery box, the reflector is an isosceles right triangle with a side length of 30 mm and a thickness of 20 mm, one side of the reflector is parallel to the side wall of the battery box to which it is connected, the installation height of the reflector is the same as that of the laser emitter, and the battery box wall thickness is 20 mm.

[0013] Preferably, the laser emitter is an infrared pulsed laser diode with a wavelength in the range of 850 nm to 1550 nm, and the laser emitter is located 20 mm above the lithium battery cell.

[0014] Preferably, the solenoid valve is a normally closed solenoid valve, and the injection duration after the solenoid valve is opened is 300 ms-800 ms.

[0015] A battery pack thermal runaway alarm and fire extinguishing method based on laser monitoring and infrared positioning includes the following steps:

[0016] S1. The integrated control unit controls the laser emitter to emit a monitoring beam, which is received by the laser receiver and outputs a signal. The light intensity signal I is collected in real time. The output signal of the laser receiver is recorded under the normal and stable state of the lithium battery pack, and the average intensity value of the signal is calibrated as the reference light intensity I0. S2. The integrated control unit controls the multi-axis motion mechanism to move, and the multi-axis motion mechanism drives the infrared detector to perform a full-coverage scan of the lithium battery array surface and records the temperature data T of the surface of each lithium battery cell. S3. When a battery experiences initial thermal runaway and gas production, the laser signal attenuates when the optical path above it scans to that location. When the laser receiver detects that the real-time light intensity signal I is lower than a preset threshold, the infrared detector scans and detects the location of the battery with a high temperature point, thereby determining the coordinates of the faulty battery. S4. The integrated control unit controls the multi-axis motion mechanism to move the fire extinguishing nozzle to the coordinates of the faulty battery, and then controls the solenoid valve to open. The fire extinguishing agent is continuously sprayed from the fire extinguishing nozzle for a certain period of time to cool and extinguish the target battery. S5. After handling, continue to monitor the infrared temperature. When the target battery temperature drops below the target temperature and does not rise again within a certain period of time, the system determines that the danger has been eliminated.

[0017] Preferably, step S3 specifically involves the following steps: the preset threshold is 0.75 I0; when the infrared detector scans and detects that the temperature at a battery location reaches 85 ℃ and the temperature of the surrounding batteries is 40 ℃, the point with a temperature of 85 ℃ is determined to be the coordinate of the faulty battery. Specifically, step S4 involves continuously spraying the extinguishing agent for 500 ms. Specifically, step S5 involves determining that the danger has been averted when the target battery temperature drops below 50°C and remains below 50°C for 30 seconds after the incident.

[0018] The beneficial effects of this invention are as follows: 1. This invention employs a non-contact laser scanning monitoring method. By detecting the light intensity attenuation caused by smoke particles and thermally induced changes in the air refractive index during laser propagation, it achieves highly sensitive sensing of the initial characteristics of battery thermal runaway. Compared to contact temperature sensors that rely on heat conduction, this method eliminates the need for heat transfer, enabling early warning at an early stage before the battery temperature significantly increases, thus significantly shortening the response time. Furthermore, by constructing a continuous reflective optical path covering the battery array, a single laser beam sequentially passes through the corresponding area of ​​each battery cell, achieving overall coverage monitoring of the battery pack. This avoids the monitoring blind spots caused by traditional discrete sensor arrangements, improving the completeness and reliability of the system monitoring, and realizing early warning and blind-spot-free monitoring of battery thermal runaway.

[0019] 2. This invention combines laser early warning with infrared thermometry. After the laser monitoring system issues an early warning signal, the infrared thermometry unit scans the warning area. By acquiring the temperature distribution and identifying abnormal temperature peaks, it achieves precise location of the battery cell experiencing thermal runaway. Based on the location result, a multi-axis motion mechanism is driven to move the fire extinguishing nozzle to the target location and perform targeted spraying on the faulty battery, thereby achieving a shift from "area response" to "cell-level response." This method effectively reduces the amount of extinguishing agent used and minimizes the impact on surrounding normal batteries and electrical equipment, improving the accuracy and safety of the response, and achieving precise location and targeted disposal of faulty batteries. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a front view of the overall structure of the present invention; Figure 3 This is a side view of the overall structure of the present invention; Figure 4 This is a top view of the beam path of the present invention; Figure 5 This is a schematic diagram of the nozzle of the present invention performing point spraying. Figure 1 ; Figure 6 This is a schematic diagram of the nozzle of the present invention performing point spraying. Figure 2 ; Figure 7 This is a partial enlarged view of the infrared detector and fire extinguishing nozzle of the present invention; Figure 8 This is a flowchart of the method of the present invention.

[0021] The following are the labels in the diagram: 1. Battery box; 2. Laser emitter; 3. Laser receiver; 4. Reflector; 5. Lithium battery; 6. Terminal; 7. Infrared detector; 8. Telescopic pipe; 9. Extinguishing agent container; 10. Solenoid valve; 11. First X-axis guide rail; 12. Second X-axis guide rail; 13. Y-axis guide rail; 14. First X-axis slider; 15. Second X-axis slider; 16. Y-axis slider; 17. Extinguishing nozzle. Detailed Implementation

[0022] To make the present invention clearer and more understandable, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the given embodiments are only one or more of the implementation methods and do not represent all embodiments.

[0023] In this article, terms such as "inner," "outer," "upper," and "lower" are established based on the positional relationships shown in the attached drawings. Depending on the attached drawings, the corresponding positional relationships may also change. Therefore, they should not be interpreted as an absolute limitation on the scope of protection.

[0024] Combined with appendix Figure 1 - Appendix Figure 7 A battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning includes a battery box 1, a laser monitoring mechanism, an infrared positioning and fire extinguishing mechanism, a multi-axis motion mechanism, and an integrated control unit. The battery box 1 contains multiple lithium battery cells 5 arranged in a rectangular array. The laser monitoring mechanism includes multiple reflectors 4, a signal processing unit, a laser emitter 2, and a laser receiver 3. The laser emitter 2 and laser receiver 3 are respectively located on opposite sides inside the battery box 1, above two diagonally positioned lithium battery cells 5. The laser receiver 3 receives the laser beam emitted by the laser emitter 2 through multiple reflectors 4. The laser beam emitted by the laser emitter 2 forms a continuous optical path that passes sequentially through each lithium battery cell 5 through multiple reflectors 4. The infrared positioning and fire extinguishing mechanism includes a fire extinguisher and an infrared detector 7. The output end of the fire extinguisher and the infrared detector 7 are movably mounted inside the battery box 1 and above the lithium battery cells 5 via the multi-axis motion mechanism. The integrated control unit is connected to the infrared detector 7, the signal processing unit, the multi-axis motion mechanism, and the fire extinguisher. The signal processing unit is connected to the laser receiver 3.

[0025] Specifically, the reflector 4 includes a first reflector, a second reflector, and multiple third reflectors. A first reflector is located on the inner wall of the battery box 1 opposite to the laser emitter 2, and its position corresponds to the laser emitter 2. A second reflector is located on the inner wall of the battery box 1 opposite to the laser receiver 3, and its position corresponds to the laser receiver 3. A third reflector is located above each row of lithium batteries 5 between the first reflector and the laser receiver 3, and also above each row of lithium batteries 5 between the second reflector and the laser emitter 2. The two reflectors 4 located above the same row of lithium batteries 5 are positioned correspondingly. The beam emitted by the laser emitter 2 passes through the multiple reflectors 4 to form a serpentine continuous optical path that sequentially passes through each individual lithium battery 5.

[0026] The infrared detector 7 is an uncooled infrared detector 7.

[0027] Specifically, the multi-axis motion mechanism includes two X-axis guide rails and one Y-axis guide rail 13. The two X-axis guide rails are respectively located on opposite sides inside the battery box 1. X-axis sliders are slidably mounted on the X-axis guide rails. The two ends of the Y-axis guide rail 13 are respectively connected to the two X-axis sliders.

[0028] The fire extinguisher includes an extinguishing agent container 9 and an extinguishing nozzle 17. The outlet of the extinguishing agent container 9 is connected to the extinguishing nozzle 17 via a telescopic pipe 8. A Y-axis slider 16 is slidably mounted on the Y-axis guide rail 13. The extinguishing nozzle 17 and an infrared detector 7 are mounted on the Y-axis slider 16. A solenoid valve 10 is provided at the outlet of the extinguishing agent container 9. The solenoid valve 10 is connected to an integrated control unit. The opening or closing of the solenoid valve 10 controls the opening or closing of the extinguishing agent release.

[0029] More specifically, the two X-axis guide rails are a first X-axis guide rail 11 and a second X-axis guide rail 12, and the two X-axis sliders are a first X-axis slider 14 and a second X-axis slider 15. A first screw is rotatably mounted on the first X-axis guide rail 11, and the first X-axis slider 14 on the first X-axis guide rail 11 is threadedly connected to the first screw. The first screw is driven to rotate by a first drive motor. A sliding rod is fixed on the second X-axis guide rail 12, and the second X-axis slider 15 on the second X-axis guide rail 12 is slidably connected to the sliding rod. A second screw is rotatably mounted on the Y-axis guide rail 13, and the Y-axis slider 16 is threadedly connected to the second screw. The second screw is driven by a second drive motor. The integrated control unit is connected to the first drive motor and the second drive motor respectively. When the drive motors are activated, the X-axis slider moves along the X-axis, and the Y-axis slider 16 moves along the Y-axis, forming a two-dimensional motion platform.

[0030] The fire extinguishing nozzle 17 and the infrared detector 7 are installed below the Y-guide rail 13, and the spray center line of the fire extinguishing nozzle 17 is perpendicular to the upper surface of the lithium battery 5; a clearance groove is opened in the middle of the Y-guide rail 13 along its Y direction, and the telescopic pipe 8 passes through the clearance groove and connects to the fire extinguishing nozzle 17.

[0031] The extinguishing agent container 9 is fixed to the outside of the battery box 1. A through hole is provided on one side of the battery box 1, and the telescopic pipe 8 passes through the through hole and is sealed to the outlet of the extinguishing agent container 9. The side wall of the battery box 1 is also provided with a through hole for the terminal 6 of the lithium battery 5 to pass through.

[0032] Specifically, the telescopic pipe 8 is a corrugated pressure-resistant flexible hose. Its telescopic stroke matches the range of motion of the multi-axis motion mechanism.

[0033] Specifically, the fire extinguishing nozzle 17 and the infrared detector 7 are arranged side by side along the Y direction. The optical axis of the infrared detector 7 is parallel to the spray center line of the fire extinguishing nozzle 17. When the fire extinguishing nozzle 17 moves along the Y direction, the center of the field of view of the infrared detector 7 at the surface of the lithium battery cell 5 coincides with the spray coverage center of the fire extinguishing nozzle 17, ensuring the accuracy of the spray position.

[0034] Specifically, the center distance between the fire extinguishing nozzle 17 and the infrared detector 7 is 40 mm; the X-guide rail is installed 300 mm above the bottom surface of the battery box 1; the laser receiver 3 and laser emitter 2 are installed 200 mm above the bottom surface of the battery box 1; the outlet of the fire extinguishing agent container 9 is 350 mm above the bottom surface of the battery box 1; the reflector 4 is an isosceles right triangle with a side length of 30 mm and a thickness of 20 mm, one side of which is parallel to the side wall of the battery box 1 to which it is connected; the installation height of the reflector 4 is the same as that of the laser emitter 2; and the wall thickness of the battery box 1 is 20 mm. More specifically, the reflector 4 is a plane reflector 4 with a high-reflectivity coating on its surface.

[0035] Specifically, the laser emitter 2 is an infrared pulsed laser diode with a wavelength in the range of 850 nm to 1550 nm, and the laser emitter 2 is located 20 mm above the lithium battery cell 5.

[0036] Specifically, the solenoid valve 10 is a normally closed solenoid valve 10, and the injection duration after the solenoid valve 10 is opened is 300 ms-800 ms.

[0037] Combined with appendix Figure 8 A battery pack thermal runaway alarm and fire extinguishing method based on laser monitoring and infrared positioning includes the following steps: S1. The integrated control unit controls the laser emitter 2 to emit a monitoring beam, which is received by the laser receiver 3 and outputs a signal to collect the light intensity signal I in real time; the output signal of the laser receiver 3 under the normal and stable state of the lithium battery pack 5 is recorded, and the average intensity value of the signal is calibrated as the reference light intensity I0. S2. The integrated control unit controls the multi-axis motion mechanism to perform a full-coverage scan of the surface of the lithium battery array 5 by the infrared detector 7, and records the temperature data T of each lithium battery cell surface. At the same time, a reference temperature distribution map can be generated and stored based on the recorded temperature data, which is convenient for staff to observe or analyze the temperature data.

[0038] S3. When a battery experiences initial thermal runaway and gas production, the laser signal attenuates when the optical path above it scans to that position. When the laser receiver 3 detects that the real-time light intensity I is lower than the preset threshold (e.g., from I0 to 0.72 I0), a first-level warning is triggered. The infrared detector 7 scans and detects the battery position with the high temperature point, thereby determining the coordinates (X, Y) of the faulty battery. S4. The integrated control unit controls the multi-axis motion mechanism to move the fire extinguishing nozzle 17 to the coordinates of the faulty battery, and then controls the solenoid valve 10 to open. The fire extinguishing agent is continuously sprayed from the fire extinguishing nozzle 17 for a certain period of time to cool and extinguish the target battery. The target battery is the faulty battery that is generating high temperature. S5. After handling the situation, continue monitoring the infrared temperature T', using temperature as the criterion for determining whether the thermal runaway hazard has been resolved: when the target battery temperature drops below the target temperature and does not rise again within a certain period of time, the system determines that the hazard has been resolved. After the hazard has been resolved, the operator opens the battery box 1 under safe conditions, completes maintenance work such as replacing the faulty battery cell, cleaning the surface of the reflector 4, calibrating the optical path, and replenishing the fire extinguishing agent, and then re-executes step S1 to calibrate the reference light intensity I0, and the system resumes the dual monitoring mode of light intensity and temperature.

[0039] Specifically, step S3 is as follows: the preset threshold is 0.75 I0; when the infrared detector 7 scans and detects that the temperature of a battery location reaches 85 ℃ and the temperature of the surrounding batteries is 40 ℃, the point with a temperature of 85 ℃ is determined to be the coordinate of the faulty battery. Specifically, step S4 involves continuously spraying the extinguishing agent for 500 ms. Specifically, step S5 involves determining that the danger has been averted when the target battery temperature drops below 50°C and remains below 50°C for 30 seconds after the incident.

[0040] Although embodiments of the invention have been shown and described, those skilled in the art will be able to make various changes, modifications, substitutions and alterations to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning, characterized in that: The system includes a battery box (1), a laser monitoring mechanism, an infrared positioning and fire extinguishing mechanism, a multi-axis motion mechanism, and an integrated control unit. The battery box (1) contains multiple lithium battery cells (5) arranged in a rectangular array. The laser monitoring mechanism includes multiple reflectors (4), a signal processing unit, a laser emitter (2), and a laser receiver (3). The laser emitter (2) and laser receiver (3) are respectively located on opposite sides inside the battery box (1). The laser emitter (2) and laser receiver (3) are positioned above two diagonally opposite lithium battery cells (5). The laser receiver (3) transmits signals through multiple... Each reflector (4) receives the light beam emitted by the laser emitter (2). The light beam emitted by the laser emitter (2) forms a continuous optical path that passes through each lithium battery (5) cell in sequence through multiple reflectors (4). The infrared positioning and fire extinguishing mechanism includes a fire extinguisher and an infrared detector (7). The output end of the fire extinguisher and the infrared detector (7) are movably disposed inside the battery box (1) and located above the lithium battery (5) cell through a multi-axis motion mechanism. The integrated control unit is connected to the infrared detector (7), the signal processing unit, the multi-axis motion mechanism and the fire extinguisher respectively. The signal processing unit is connected to the laser receiver (3).

2. The battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning according to claim 1, characterized in that: The multi-axis motion mechanism includes two X-axis guide rails and one Y-axis guide rail (13). The two X-axis guide rails are respectively located on opposite sides inside the battery box (1). X-axis sliders are slidably mounted on the X-axis guide rails. The two ends of the Y-axis guide rail (13) are respectively connected to the two X-axis sliders.

3. The battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning according to claim 2, characterized in that: The fire extinguisher includes an extinguishing agent container (9) and an extinguishing nozzle (17). The outlet of the extinguishing agent container (9) is connected to the extinguishing nozzle (17) through a telescopic pipe (8). A Y-axis slider (16) is slidably provided on the Y-axis guide rail (13). The extinguishing nozzle (17) and an infrared detector (7) are located on the Y-axis slider (16). A solenoid valve (10) is provided at the outlet of the extinguishing agent container (9). The solenoid valve (10) is connected to an integrated control unit.

4. The battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning according to claim 3, characterized in that: The telescopic pipe (8) is a corrugated pressure-resistant hose.

5. The battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning according to claim 3, characterized in that: The fire extinguishing nozzle (17) and the infrared detector (7) are arranged side by side along the Y direction.

6. The battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning according to claim 5, characterized in that: The center distance between the fire extinguishing nozzle (17) and the infrared detector (7) is 40 mm. The X-guide rail is installed at a height 300 mm from the bottom of the battery box (1). The laser receiver (3) and the laser emitter (2) are installed at a height 200 mm from the bottom of the battery box (1). The outlet of the fire extinguishing agent container (9) is 350 mm from the bottom of the battery box (1). The reflector (4) is an isosceles right triangle with a side length of 30 mm and a thickness of 20 mm. One side of the reflector (4) is parallel to the side wall of the battery box (1) to which it is connected. The installation height of the reflector (4) is the same as that of the laser emitter (2). The wall thickness of the battery box (1) is 20 mm.

7. The battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning according to claim 6, characterized in that: The laser emitter (2) is an infrared pulsed laser diode with a wavelength in the range of 850 nm to 1550 nm, and the laser emitter (2) is located 20 mm above the lithium battery (5) cell.

8. The battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning according to claim 6, characterized in that: The solenoid valve (10) is a normally closed solenoid valve (10), and the injection time after the solenoid valve (10) is opened is 300 ms-800 ms.

9. A battery pack thermal runaway alarm and fire extinguishing method based on laser monitoring and infrared positioning, implemented based on the battery pack thermal runaway alarm and fire extinguishing device based on laser monitoring and infrared positioning as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. The integrated control unit controls the laser emitter (2) to emit a monitoring beam, which is received by the laser receiver (3) and outputs a signal. The light intensity signal I is collected in real time. The output signal of the laser receiver (3) under the normal and stable state of the lithium battery (5) is recorded, and the average intensity value of the signal is calibrated as the reference light intensity I0. S2. The integrated control unit controls the multi-axis motion mechanism to move, and the multi-axis motion mechanism drives the infrared detector (7) to perform a full-coverage scan on the surface of the lithium battery (5) array and record the temperature data T of each lithium battery (5) cell surface. S3. When a battery experiences initial thermal runaway and gas production, the laser signal attenuates when the optical path above it scans to that position. When the laser receiver (3) detects that the real-time light intensity signal I is lower than the preset threshold, the infrared detector (7) scans and detects the battery position with a high temperature point, thereby determining the coordinates of the faulty battery. S4. The integrated control unit controls the multi-axis motion mechanism to move the fire extinguishing nozzle (17) to the coordinates of the faulty battery, and then controls the solenoid valve (10) to open. The fire extinguishing agent is continuously sprayed from the fire extinguishing nozzle (17) for a certain period of time to cool and extinguish the target battery. S5. After handling, continue to monitor the infrared temperature. When the target battery temperature drops below the target temperature and does not rise again within a certain period of time, the system determines that the danger has been eliminated.

10. A battery pack thermal runaway alarm and fire extinguishing method based on laser monitoring and infrared positioning according to claim 9, characterized in that: The specific step S3 is as follows: the preset threshold is 0.75 I0; when the infrared detector (7) scans and detects that the temperature of a battery location reaches 85 ℃ and the temperature of the surrounding batteries is 40 ℃, the point with a temperature of 85 ℃ is determined to be the coordinate of the faulty battery. Specifically, step S4 involves continuously spraying the extinguishing agent for 500 ms. Specifically, step S5 involves determining that the danger has been averted when the target battery temperature drops below 50°C and remains below 50°C for 30 seconds after the incident.

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