Method for detecting thermal runaway of lithium battery based on infrared thermal imager

Abstract

The invention discloses a method for detecting thermal runaway of a lithium battery based on an infrared thermal imager, which is characterized by comprising the following steps: (1) detecting an infrared ray specific wave band signal of thermal radiation of an object by using a photoelectric technology through the infrared thermal imager, and converting the signal into an image and a graph which can be visually distinguished by human beings; (2) carrying out graph preprocessing on the images, carrying out denoising by utilizing a median filtering method, and framing a candidate region; and (3) carrying out non-maximum suppression (NMS) processing on the candidate area to obtain a motion area with the highest temperature, calculating the highest temperature of the motion area, and judging whether the highest temperature exceeds a preset threshold value or not so as to judge whether to give an alarm or not. The invention has the following beneficial effects: (1) the alarm time is shortened; (2) an alarm area can be visually observed, and time is won for rescue; and (3) the invention can adapt to different lithium battery transportation and storage environments by adjusting the set alarm threshold value, and the fire monitoring efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of thermal runaway detection of lithium batteries, in particular to a method for detecting thermal runaway of lithium batteries based on an infrared thermal imager. Background technique [0002] With the gradual growth of the market size of new energy vehicles and the expansion of demand for energy storage batteries, the output of lithium batteries in my country will continue to increase from 2015 to 2020. In 2020, my country's lithium-ion battery output will reach 18.845 billion, an increase of 19.87% compared with 2019. With the increase in the total shipment of lithium batteries year by year, the transportation volume of lithium batteries in my country has also increased exponentially. According to the survey, lithium batteries account for more than 75% of the total transportation of all dangerous goods every year. As we all know, once the thermal runaway of a lithium battery occurs, it has the character...

AI Technical Summary

Problems solved by technology

Ionization smoke detectors are made based on the principle that smoke generated during a fire can change the conductivity of the air. However, because ionization smoke detectors are greatly affected by factors such as temperature, humidity, and dust, it is easy to induce The phenomenon of false alarms and false alarms, the alarm is not suitable for places with a large amount of dust, steam, smoke, oil mist, water mist, etc., because once the interfering particles change the ionization of the air in the detection room, the detector will feedback false signal

At the same time, there are radioactive substances in the detector, which will pose a threat to personal safety and the ecological environment.

Photoelectric smoke detectors are typical smoke detectors, which are developed by using the basic property that smoke can change the propagation characteristics of light, but because photoelectric smoke detectors are essentially particle detectors and are less sensitive to black smoke Low, false signals are often generated, and the transport cabin is easy to produce interference particles. Once these interference particles float into the detection room, when the infrared light of the detector produces enough reflection and scattering, it will lead to an increase in the photocurrent in the photocell, resulting in false signals. fire alarm

Since the detector can only detect particles with a particle size larger than 0.4 μm, and cannot distinguish the properties of the material entering the sensor detection chamber, the typical difference between normal conditions and fire conditions is only 0.09%, and the small signal changes It will make the detector very susceptible to interference factors, and this type of fire alarm cannot detect the presence of combustible gases such as carbon monoxide, resulting in frequent false alarms

[0005] In addition, when the cargo hold space is large enough, the smoke detector will not alarm until the smoke particles enter the detector detection room, which will cause the alarm time to be too long and miss the best time to extinguish the fire

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