Battery thermal runaway early warning device based on dual-optical-path detection

Abstract

The utility model relates to a battery thermal runaway early warning device based on double-light-path detection in the technical field of battery safety monitoring. The battery thermal runaway early warning device comprises a detection light path, a reference light path, a signal processing unit and a grading alarm module. The detection light path is composed of a low-intensity LED light source and a first photoelectric sensor, and the light path accurately penetrates through a battery thermal runaway sensitive area; the reference light path adopts the same light source and a second photoelectric sensor, avoids a sensitive area, is packaged in a light guide tube and is used for eliminating environmental noise. Two paths of light intensity signals are calculated through difference, air disturbance and gas / smoke generation are distinguished by combining a frequency analysis technology, and multi-stage early warning from the early stage to the middle stage of thermal runaway is achieved. The device adopts a reflecting mirror group for prolonging the optical path, a light guide pipe for anti-interference packaging and a grading alarm mechanism, has the advantages of low cost, high sensitivity, low false alarm rate and the like, can effectively solve the problems of delayed early warning, high false alarm rate of a gas sensor and the like in a traditional laser shielding method, and provides reliable safety guarantee for an energy storage battery system.

Description

Technical Field

[0001] This utility model belongs to the field of battery safety monitoring technology, and relates to a battery thermal runaway early warning device based on dual optical path detection. Background Technology

[0002] With the rapid development of the new energy industry, the scale of electrochemical energy storage power stations continues to expand, and their battery safety has attracted much attention. Thermal runaway is one of the main risks in the field of battery safety, and existing thermal runaway detection technologies have many shortcomings. The laser shielding method relies on the opening of the battery safety valve to trigger a warning, with an average delay of ≥60 seconds, making it impossible to detect problems in the early stages of thermal runaway; gas sensors are expensive, have complex signal processing, are sensitive to environmental vibrations and temperature drift, and have a high false alarm rate. Single signal monitoring can only detect temperature or gas, and cannot cover the entire thermal runaway cycle. These technical bottlenecks severely restrict the improvement of battery safety performance, and there is an urgent need for a low-cost, high-sensitivity, and interference-resistant thermal runaway early warning device. Utility Model Content

[0003] In view of the above situation, this utility model provides a battery thermal runaway early warning device based on dual optical path detection, which can effectively overcome the problems of early warning lag, high cost and poor anti-interference in the prior art, and provide reliable protection for the safe operation of batteries.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A battery thermal runaway early warning device based on dual-optical-path detection includes a detection optical path and a reference optical path arranged parallel to each other above the battery module from bottom to top, as well as a differential early warning system for receiving and processing the signals from the two optical paths and issuing graded alarms accordingly after calculation and analysis.

[0006] The detection optical path includes a first light source and a first photoelectric sensor; the reference optical path includes a second light source and a second photoelectric sensor; a reflector is provided opposite to the two sets of light sources and photoelectric sensors to reflect the light emitted by the two light sources back to the two photoelectric sensors and extend the optical path to twice the original path, and the detection sensitivity can reach 0.1% light intensity change; the two sets of light sources and photoelectric sensors are aligned on the same side of the battery module, the reflector is installed on the other side of the battery module, and the second light source and the second photoelectric sensor of the reference optical path are encapsulated in a light guide tube.

[0007] Furthermore, the detection optical path horizontally passes through the battery thermal runaway sensitive area 5mm±0.5mm above the battery safety valve, and the first light source preferably adopts a low-intensity LED light source with an emission wavelength of 400-900nm and a power of ≤10mW.

[0008] Furthermore, the reference optical path and the detection optical path are arranged parallel to each other, avoiding the sensitive area of ​​battery thermal runaway. The reference optical path is offset upwards by 2cm ± 0.5cm from its horizontal position, and the spacing between the optical paths helps to avoid signal cross-interference. The second light source and the second photoelectric sensor of the reference optical path are encapsulated within a light guide tube. The light guide tube is preferably a transparent quartz light guide tube, with a nano-anti-scattering coating on its outer wall. The distance between the second light source of the reference optical path and the inner wall of the light guide tube is fixed at 2cm ± 0.2cm.

[0009] Furthermore, the first light source and the first photoelectric sensor of the detection optical path are integrated and packaged within a housing one, which is mounted on the inner wall of the battery module via an elastic bracket. The second light source and the second photoelectric sensor of the reference optical path are integrated and packaged within a housing two, which is connected to and mounted above the housing one via a connecting pipe. The power and signal cables of the reference optical path pass through the connecting pipe and enter the housing one.

[0010] Furthermore, the differential warning system is also integrated and packaged within the housing. The first light source and the first photoelectric sensor of the detection optical path, as well as the second light source and the second photoelectric sensor of the reference optical path, are all connected to the differential warning system. Power and signal cables are externally connected to the bottom of the housing.

[0011] Furthermore, the differential early warning system includes a signal processing unit for receiving and calculating the light intensity difference between the two optical paths in real time and analyzing the frequency of the light intensity signal, as well as a graded alarm module for triggering graded alarms and sending remote notifications based on the differential calculation of the light intensity signal drop. Differential calculation eliminates common-mode noise (such as LED aging and environmental temperature drift), increasing the signal-to-noise ratio to 5 times that of traditional single-path detection.

[0012] Furthermore, the signal processing unit extracts the frequency domain features of the light intensity signal through Fourier transform, analyzes and distinguishes high-frequency air disturbance signals (>10Hz) from low-frequency gas / smoke signals (<1Hz), thereby achieving accurate identification of different stages of battery thermal runaway.

[0013] Frequency domain hierarchical early warning; the signal processing unit performs Fast Fourier Transform (FFT) on the differential signal to extract high-frequency signals above 10Hz (air disturbance) and low-frequency signals below 1Hz (gas production / smoke); combined with the light intensity decrease (30%±2% for Level 1 warning and 50%±3% for Level 2 warning) and duration (2 seconds±0.5 seconds), multi-stage accurate alarm is achieved.

[0014] The signal processing unit acquires the light intensity signals of the detection optical path and the reference optical path in real time at a sampling rate of not less than 100Hz. After eliminating common-mode noise through differential operation, it performs a Fast Fourier Transform (FFT) on the differential signals to extract the frequency domain features of the light intensity signals. Signals with frequencies higher than 10Hz are identified as air disturbances, and signals with frequencies lower than 1Hz are identified as gas or smoke generation. Based on the magnitude and duration of the light intensity decrease, the graded alarm module triggers different levels of alarms: when the light intensity decreases by 30%±2% and lasts for more than 2 seconds, it is determined as a Level 1 warning (air disturbance stage); when the light intensity decreases by 50%±3% and lasts for more than 2 seconds, it is determined as a Level 2 warning (gas or smoke generation stage), and outputs corresponding control signals or remote notifications respectively.

[0015] This utility model also includes other components that enable its normal use, all of which are conventional means in the field. In addition, devices or components not limited in this utility model, such as battery modules, battery safety valves, photoelectric sensors, reflectors, elastic brackets, quartz light guides and nano anti-scattering coatings, all adopt existing technologies in the field.

[0016] The beneficial effects of this utility model are as follows:

[0017] 1. Early warning capability: By capturing air disturbance signals in the early stages of thermal runaway, the warning time is more than 50% earlier than traditional methods;

[0018] 2. High sensitivity and anti-interference: The dual-optical-path differential design effectively eliminates environmental noise, and combined with the reflector group to extend the optical path, the detection sensitivity is increased by 3 times;

[0019] 3. Low-cost deployment: It adopts a low-intensity LED light source and a compact light guide tube package, and the cost is only 1 / 5 of that of a gas sensor;

[0020] 4. Multi-stage monitoring: It can simultaneously identify early (air disturbance) and mid-stage (gas production / smoke) signals of thermal runaway, filling a technological gap;

[0021] 5. Tiered alarm mechanism: Different levels of early warning are triggered based on the magnitude and duration of signal changes, guiding maintenance personnel to take targeted measures. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the installation of the battery thermal runaway early warning device in this utility model.

[0023] Figure 2 for Figure 1 A schematic diagram of the overall structure of the battery thermal runaway early warning device.

[0024] In the diagram: 1. Sealing strip; 2. Reflector; 3. Light guide tube; 4. Second light source; 5. First light source; 6. First photoelectric sensor; 7. Power supply and signal cable; 8. Connecting pipe; 9. Second photoelectric sensor; 10. Battery cell; 11. Housing 1; 12. Housing 2. Detailed Implementation

[0025] The technical solution of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0026] Example

[0027] like Figure 1-2 As shown, a battery thermal runaway early warning device based on dual-optical-path detection includes a detection optical path and a reference optical path arranged parallel to each other above the battery module from bottom to top, as well as a differential early warning system for receiving and processing the signals from the two optical paths and issuing graded alarms accordingly after calculation and analysis.

[0028] The detection optical path includes a first light source 5 and a first photoelectric sensor 6; the reference optical path includes a second light source 4 and a second photoelectric sensor 9; a reflector 2 is provided opposite to the two sets of light sources and photoelectric sensors, and the two sets of optical paths share the same reflector, which is used to reflect the light emitted by the two light sources back to the two photoelectric sensors and extend the optical path to twice the original path (i.e., the width of the battery module). The battery module is assembled from several battery cells 10. The detection sensitivity can reach 0.1% light intensity change, which can capture the micro-airflow disturbance signal in the early stage of battery thermal runaway, and the warning time is at least 50 seconds earlier than the traditional method.

[0029] Two sets of light sources and photoelectric sensors are aligned and set on the left side of the battery module, and a reflector is installed on the right side of the battery module. The second light source and the second photoelectric sensor for the reference optical path are encapsulated in the light guide tube 3.

[0030] Both the first light source of the detection optical path and the second light source of the reference optical path use low-intensity LED light sources with the same emission wavelength of 470nm. The detection optical path passes horizontally through the battery thermal runaway sensitive area 5mm above the battery safety valve.

[0031] The reference optical path and the detection optical path are arranged in parallel to avoid the sensitive area of ​​battery thermal runaway, and the detection optical path is offset upward by 2cm at the horizontal height position.

[0032] The light guide tube is preferably a transparent quartz light guide tube, and its outer wall is coated with a nano anti-scattering coating. The distance between the second light source of the reference light path and the inner wall of the transparent light guide tube is fixed at 2cm ± 0.2cm.

[0033] The second light source and the second sensor of the reference optical path are sealed in a cylindrical light guide tube. The light guide tube is located between the second light source and the second sensor of the reference optical path and the reflector. The two ends of the light guide tube are fitted with sealing strips 1, and the stray light suppression rate is >90%. The light guide tube is fixed to the non-hot area of ​​the edge of the battery module and the vibration is buffered by the elastic bracket to ensure the stability of the reference signal (fluctuation <0.5%).

[0034] The first light source and the first photoelectric sensor of the detection optical path are integrated and packaged in housing 11. Housing 1 is mounted on the inner wall of the battery module via an elastic bracket. The second light source and the second photoelectric sensor of the reference optical path are integrated and packaged in housing 12. Housing 12 is connected to and mounted above housing 1 via a connecting pipe 8. The power supply and signal lines of the reference optical path pass through the connecting pipe and enter housing 1.

[0035] The differential warning system is also integrated and packaged in the housing. The first light source and the first photoelectric sensor of the detection optical path, as well as the second light source and the second photoelectric sensor of the reference optical path, are all connected to the differential warning system. Power supply and signal cables 7 are externally connected to the bottom of the housing.

[0036] The differential early warning system includes a signal processing unit for receiving and calculating the light intensity difference between two optical paths in real time and analyzing the frequency of the light intensity signal, as well as a graded alarm module for triggering graded alarms and sending remote notifications based on the differential calculation of the light intensity signal drop.

[0037] The signal processing unit acquires two light intensity signals at a sampling rate of 100Hz, calculates the real-time difference, extracts the frequency domain features of the light intensity signals through Fourier transform, analyzes and distinguishes high-frequency air disturbance signals (>10Hz) and low-frequency gas / smoke signals (<1Hz), thereby achieving accurate identification of different stages of battery thermal runaway.

[0038] When the detection optical path signal drops by 30% for 2 seconds, it is determined to be a Level 1 warning (air disturbance stage), and the fan cooling is activated; if the difference increases to 50%, it is determined to be a Level 2 warning (gas generation stage), and the fire extinguishing system is triggered and maintenance personnel are notified.

[0039] Interference tests have verified that the device exhibits a reference optical path signal fluctuation of <0.3% and a detection optical path sensitivity of 0.15% in a -40℃ low-temperature environment; under vibration testing (5Hz~200Hz), the false alarm rate is <1.8%.

[0040] This device achieves multi-stage accurate early warning of battery thermal runaway through a specially designed optical detection scheme. It employs a reflector array to extend the optical path, a light guide tube for anti-interference encapsulation, and a tiered alarm mechanism, offering advantages such as low cost (only 1 / 5 of traditional gas sensor solutions), high sensitivity (detecting light intensity changes ≥0.1%), low false alarm rate (false alarm rate <2%), and environmental adaptability (-40℃~85℃). By differentially calculating two light intensity signals and combining frequency analysis technology to distinguish between air disturbances (high-frequency signals) and gas / smoke generation (low-frequency signals), it achieves multi-stage early warning from the early to mid-stages of thermal runaway. By detecting air disturbance signals in the early stages of thermal runaway, the warning delay is ≤10 seconds. It covers the early to mid-stages of thermal runaway, supports tiered emergency response, and overcomes the problems of delayed warnings, high costs, and poor anti-interference in existing technologies. Through dual-optical-path detection, it achieves early monitoring of battery thermal runaway, providing reliable protection for the safe operation of batteries, and is particularly suitable for scenarios with high battery safety requirements, such as energy storage power stations.

[0041] The technical solution of this utility model is not limited to the specific embodiments described above. Without departing from the scope and spirit of the described embodiments, many modifications and changes will be obvious to those skilled in the art. Any technical modifications made within the spirit and principles of this utility model shall fall within the protection scope of this utility model.

Claims

1. A battery thermal runaway early warning device based on double optical path detection, characterized by: It includes a detection optical path and a reference optical path arranged in parallel above the battery module from bottom to top, as well as a differential early warning system for receiving and processing the signals from the two optical paths and issuing graded alarms after calculation and analysis. The detection optical path includes a first light source and a first photoelectric sensor; the reference optical path includes a second light source and a second photoelectric sensor; a reflector is provided opposite to the two sets of light sources and photoelectric sensors to reflect the light emitted by the two light sources back to the two photoelectric sensors and extend the optical path to twice the original path; the two sets of light sources and photoelectric sensors are aligned on the same side of the battery module, the reflector is installed on the other side of the battery module, and the second light source and the second photoelectric sensor of the reference optical path are encapsulated in a light guide tube. 2.The battery thermal runaway early warning device based on dual optical path detection of claim 1, wherein: The detection optical path passes horizontally through the battery thermal runaway sensitive area 5mm±0.5mm above the battery safety valve, and the first light source is a low-intensity LED light source with an emission wavelength of 400-900nm. 3.The battery thermal runaway pre-warning device based on dual optical path detection of claim 2, wherein: The reference optical path avoids the sensitive area of ​​battery thermal runaway and is located at a horizontal height of 2cm ± 0.5cm directly above the detection optical path.

4. The battery thermal runaway pre-warning device based on double optical path detection according to claim 1, characterized in that: The light guide tube is a transparent quartz light guide tube with an anti-scattering coating on its outer wall, and the distance between the second light source of the reference light path and the inner wall of the light guide tube is 2cm ± 0.2cm.

5. The battery thermal runaway pre-warning device based on dual optical path detection according to claim 1, characterized in that: The first light source and the first photoelectric sensor of the detection optical path are integrated and packaged in a housing, which is mounted on the side wall of the battery module by an elastic bracket. 6.The battery thermal runaway pre-warning device based on dual optical path detection of claim 5, wherein: The second light source and the second photoelectric sensor of the reference optical path are integrated and packaged in the second housing. The second housing is connected to and installed above the first housing via a connecting pipe.

7. The battery thermal runaway pre-warning device based on dual optical path detection according to claim 6, characterized in that: The differential warning system is also integrated and packaged in the housing. The first light source and the first photoelectric sensor of the detection optical path, as well as the second light source and the second photoelectric sensor of the reference optical path, are all connected to the differential warning system. Power and signal cables are connected to the bottom of the housing. 8.The battery thermal runaway pre-warning device based on dual optical path detection of claim 1, wherein: The differential early warning system includes a signal processing unit for receiving and calculating the light intensity difference between two optical paths in real time and analyzing the frequency of the light intensity signal, as well as a graded alarm module for triggering graded alarms and sending remote notifications based on the magnitude of the decrease in light intensity signal. 9.The battery thermal runaway pre-warning device based on dual optical path detection of claim 8, wherein: The signal processing unit extracts the frequency domain features of the light intensity signal through Fourier transform, analyzes and distinguishes high-frequency air disturbance signals from low-frequency gas / smoke signals, thereby achieving accurate identification of different stages of battery thermal runaway.

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