Lithium ion battery state monitoring device and method based on composite element

Abstract

The invention relates to the technical field of energy storage system safety monitoring, and particularly provides a lithium ion battery state monitoring device and method based on a composite element, and the device comprises an infrared laser transmitter which is arranged in a lithium ion battery core and is used for irradiating electrolyte in the lithium ion battery core and generating a reflected light signal; the composite fluorescent optical fiber is arranged in the battery core and is used for collecting a radiation light signal generated by an abnormal power generation reaction in the lithium ion battery core and a reflection light signal generated by temperature change caused by an abnormal chemical reaction; the composite optical fiber penetrating device is arranged in the lithium ion battery core, and the composite fluorescent optical fiber is connected with the first end of the composite optical fiber penetrating device and used for transmitting a radiation light signal and a reflection light signal collected by the composite fluorescent optical fiber in the lithium ion battery core to the outside of the lithium ion battery core. The state of the lithium ion battery can be monitored in real time.

Description

Technical Field

[0001] The present invention belongs to the technical field of safety monitoring of energy storage systems, and particularly relates to a lithium-ion battery state monitoring device and method based on a composite element. Background Art

[0002] With the growth of global energy demand, lithium-ion batteries have become an important part of energy storage power stations due to their high energy density, long life, and high efficiency. However, when lithium-ion batteries operate under high-capacity and high-voltage conditions, there are safety hazards.

[0003] Currently, the electrical signal monitoring technologies commonly used in energy storage power stations, such as voltage, current, and resistance detection, can only monitor the external operating state of the battery and cannot obtain the internal state information of the battery in real time. In addition, the response speed of these monitoring methods is relatively slow, and usually, an alarm can only be issued after a fire has occurred or spread, missing the best response time. This monitoring delay makes it difficult to provide early warning of fires, further increasing the accident risk. At the same time, after the battery undergoes thermal runaway, its residual heat combined with the battery characteristics is likely to cause re-ignition, exacerbating the complexity of accident handling.

[0004] To solve the above problems, it has become an inevitable trend to develop technologies that can monitor the internal state of the battery in real time. As an emerging non-electrical signal, optical signals have great potential in battery state monitoring due to their pure and stable characteristics. However, currently, the monitoring methods based on fluorescent optical fibers are mainly divided into temperature measurement methods and light measurement methods. The temperature measurement method is for the change in battery temperature, and the light measurement method is used to capture the optical signals generated by abnormal discharge or chemical reactions. However, these methods usually can only monitor a certain state separately and cannot comprehensively reflect the operating conditions of the battery. Summary of the Invention

[0005] Aiming at the problems of the existing technology that the response speed is relatively slow when using electrical signals for detection, usually an alarm can only be issued after a fire has occurred or spread, showing hysteresis, but when using optical signals for detection, only a certain state can be monitored separately and the operating conditions of the battery cannot be comprehensively reflected, the present invention provides a lithium-ion battery state monitoring device and method based on a composite element to solve the above technical problems.

[0006] In a first aspect, the present invention provides a lithium-ion battery state monitoring device based on a composite element, including: An infrared laser emitter, which is arranged inside the lithium-ion battery core and is used for irradiating the electrolyte inside the lithium-ion battery core to generate a reflected optical signal; A composite fluorescent optical fiber, which is arranged inside the battery core and is used for collecting the radiation optical signal generated by abnormal power generation reactions inside the lithium-ion battery core and the reflected optical signal generated by the temperature change caused by abnormal chemical reactions; A composite optical fiber penetrator, the composite optical fiber penetrator is disposed inside a lithium-ion battery core, and the composite fluorescent optical fiber is connected to a first end of the composite optical fiber penetrator for transmitting radiation optical signals and reflected optical signals collected by the composite fluorescent optical fiber inside the lithium-ion battery core to the outside of the lithium-ion battery core; A composite quartz optical fiber, the composite quartz optical fiber is disposed outside the lithium-ion battery core, and a first end of the composite quartz optical fiber is connected to a second end of the composite optical fiber penetrator for transmitting optical signals; A composite optical fiber collimator, the composite optical fiber collimator is connected to a second end of the composite quartz optical fiber for converting the optical signals in the composite quartz optical fiber into two parallel optical signals with uniform distribution; A composite photodiode, the composite optical fiber collimator is connected to the composite photodiode for detecting the collimated optical signals.

[0007] Further, the composite fluorescent optical fiber sequentially includes a fluorescent outer cladding, a first fluorescent optical fiber, a fluorescent isolation layer, and a second fluorescent optical fiber from outside to inside; The fluorescent outer cladding includes a transparent anti-corrosion material, the fluorescent outer cladding includes an outer side and an inner side of the fluorescent outer cladding, and the laser generated by the infrared laser emitter can only enter the inner side of the fluorescent outer cladding from the outer side of the fluorescent outer cladding; The first fluorescent optical fiber is used for collecting radiation optical signals generated by abnormal power generation reactions or abnormal chemical reactions inside the lithium-ion battery core; The second fluorescent optical fiber of the composite fluorescent optical fiber is used for collecting reflected optical signals generated by temperature changes caused by abnormal chemical reactions inside the lithium-ion battery core; The fluorescent isolation layer includes an outer side and an inner side of the fluorescent isolation layer, and both the outer side and the inner side of the fluorescent isolation layer are covered with or made of a high-reflection material for isolating the radiation optical signals in the first fluorescent optical fiber from the reflected optical signals in the second fluorescent optical fiber, so that the radiation optical signals in the first fluorescent optical fiber are reflected back to the first fluorescent optical fiber, and the reflected optical signals in the second fluorescent optical fiber are reflected back to the second fluorescent optical fiber.

[0008] Further, the composite optical fiber penetrator includes a first optical fiber interface, a second optical fiber interface, a penetrator body, and a central lens. The central lens is embedded in the center of the penetrator body, and the central lens includes an outer embedding layer, an outer lens layer, an isolation layer, and an inner lens layer; The first optical fiber interface is connected to the composite fluorescent optical fiber, the second optical fiber interface is connected to the composite quartz optical fiber, and the first optical fiber interface and the second optical fiber interface are ST interfaces and are both provided with sealing devices; The outer embedding layer is used for tightly embedding with the composite optical fiber penetrator and protecting the outer lens layer; The outer lens layer is used to transmit the radiation optical signal collected by the first fluorescent optical fiber of the composite fluorescent optical fiber to the first quartz optical fiber; The isolation layer is used to isolate the radiation optical signal collected by the first fluorescent optical fiber of the composite fluorescent optical fiber and the reflected optical signal collected by the second fluorescent optical fiber of the composite fluorescent optical fiber, preventing the mixing of the radiation optical signal and the reflected optical signal; The inner lens layer is used to transmit the reflected optical signal collected by the second fluorescent optical fiber of the composite fluorescent optical fiber to the second quartz optical fiber.

[0009] Further, the composite quartz optical fiber sequentially includes a quartz outer cladding, a first quartz optical fiber, a quartz isolation layer, and a second quartz optical fiber from outside to inside; The quartz outer cladding is an insulating material. The outside of the quartz outer cladding is used to prevent the interference optical signal in the environment from entering the first quartz optical fiber, and the inside of the quartz outer cladding is used to reflect the radiation optical signal in the first quartz optical fiber back into the first quartz optical fiber; The first quartz optical fiber of the composite quartz optical fiber is used to transmit the radiation optical signal collected by the first fluorescent optical fiber of the composite fluorescent optical fiber; The quartz isolation layer of the composite quartz optical fiber is made of a high-reflection material or covered with a high-reflection coating, which is used to reflect the radiation optical signal in the first quartz optical fiber back into the first quartz optical fiber, reflect the reflected optical signal in the second quartz optical fiber back into the second quartz optical fiber, and isolate the optical signals in the first quartz optical fiber and the second quartz optical fiber, preventing the mixing of the radiation optical signal and the reflected optical signal; The second quartz optical fiber of the composite quartz optical fiber is used to transmit the reflected optical signal collected by the second fluorescent optical fiber of the composite fluorescent optical fiber.

[0010] Further, the composite fiber collimator includes a collimation outer layer and a collimation inner layer; The collimation outer layer and the collimation inner layer are respectively used to convert the radiation optical signal of the first quartz optical fiber of the composite quartz optical fiber and the reflected optical signal of the second quartz optical fiber of the composite quartz optical fiber from a chaotic optical signal into a uniformly distributed parallel optical signal.

[0011] Further, the composite photodiode includes a collimation outer layer photosensitive area and a collimation inner layer photosensitive area; The collimation outer layer photosensitive area is used to detect the collimated radiation optical signal; The collimation inner layer photosensitive area is used to detect the collimated reflected optical signal.

[0012] Further, the wavelength band of the radiation optical signal includes 200 - 1000 nm; The wavelength band of the reflected optical signal includes 1000 - 2500 nm.

[0013] In a second aspect, the present invention provides a method for monitoring the state of a lithium-ion battery based on a composite component, including: The first fluorescent optical fiber and the second fluorescent optical fiber based on the composite fluorescent optical fiber respectively collect the radiation optical signal and the reflected optical signal inside the lithium-ion battery cell; The radiation optical signal and the reflected optical signal respectively pass through the outer lens layer and the inner lens layer of the composite optical fiber penetrator and are respectively transmitted from inside the lithium-ion battery cell to the first quartz optical fiber and the second quartz optical fiber of the composite quartz optical fiber; The radiation optical signal in the first quartz optical fiber and the reflected optical signal in the second quartz optical fiber are respectively converted into uniformly distributed parallel light through the collimation outer layer and the collimation inner layer of the composite optical fiber collimator; The parallel radiation optical signal is projected onto the collimation outer layer photosensitive area of the composite photodiode and converted into a first electrical signal, and the parallel reflected optical signal is projected onto the collimation inner layer photosensitive area of the composite photodiode and converted into a second electrical signal; Use an analog-to-digital converter to convert the first electrical signal into a first digital signal, convert the second electrical signal into a second digital signal, and access a computer through a signal transmission bus; Input the first digital signal and the second digital signal into a pre-established lithium-ion battery fault handling model to determine whether there is an abnormality in the current operating state of the lithium-ion battery. If there is an abnormality, an alarm is given.

[0014] Further, inputting the first digital signal and the second digital signal into a pre-established lithium-ion battery fault handling model to determine whether there is an abnormality in the current operating state of the lithium-ion battery includes: Obtain the operating data of the lithium-ion battery from normal operation to the average value of the critical temperature of thermal runaway in the first preset temperature range, and form a first data set; Import the first data set into a pre-established lithium-ion battery thermal runaway simulation model, and through the lithium-ion battery thermal runaway simulation model, obtain the radiation optical and reflected optical data of the average value of the critical temperature of thermal runaway in the second preset temperature range, and form a second data set; Collect the first data set and the second data set, and obtain the radiation optical and reflected optical data of the lithium-ion battery in the full temperature operating range in the first data set and the second data set, and form a third data set; Perform feature extraction on the third data set, and obtain the maximum pulse amplitude of the radiation optical signal, the radiation optical pulse repetition rate, the temperature corresponding to the reflected optical signal, the temperature rise rate corresponding to the reflected optical signal, the waveform similarity and the mutual information coefficient between the reflected optical signal and the radiation optical signal at the same time, and form a first sample set; Intercept the data samples in the first sample set where the temperature is less than the average value of the critical temperature of thermal runaway, and form a second sample set; Perform clustering processing on the second sample set, divide the second sample set into five sets and label them, which are respectively denoted as the third sample set, the fourth sample set, the fifth sample set, the sixth sample set, and the seventh sample set; Based on the third sample set, the fourth sample set, the fifth sample set, the sixth sample set, and the seventh sample set, train the pre-established lithium-ion battery operating state monitoring model to obtain a lithium-ion battery fault handling model.

[0015] Furthermore, if there is an abnormality, an alarm is issued, including: Issuing a warning and an alarm sound, starting the self-protection mechanism of the lithium-ion battery, disconnecting the connection between the lithium-ion battery and the outside, and automatically starting the fire-fighting cooling means if the temperature of the lithium-ion battery still shows an upward trend within 10 s.

[0016] The beneficial effects of the present invention are that the lithium-ion battery state monitoring device and method based on a composite element provided by the present invention collect the radiation light signal and the reflected light signal inside the lithium-ion battery core simultaneously through a composite fluorescent optical fiber, and transmit the radiation light signal and the reflected light signal to the outside of the lithium-ion battery core through a composite optical fiber penetrator and a composite quartz optical fiber in separate channels, which can ensure that the signals do not interfere with each other and are transmitted efficiently, and use a composite fiber collimator to collimate the radiation light signal and the reflected light signal, and convert the radiation light signal and the reflected light signal into electrical signals respectively through a composite photodiode, so as to realize the independence, integrity, and real-time nature of the lithium-ion battery state monitoring. In addition, the design principle of the present invention is reliable, the structure is simple, and it has a very wide application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a composite fluorescent optical fiber according to an embodiment of the present invention.

[0019] Figure 2 It is a schematic structural diagram of a composite fluorescent optical fiber according to another embodiment of the present invention.

[0020] Figure 3 It is a schematic structural diagram of a composite optical fiber penetrator according to an embodiment of the present invention.

[0021] Figure 4 It is a schematic structural diagram of a central lens according to an embodiment of the present invention.

[0022] Figure 5It is a schematic structural diagram of a composite quartz optical fiber according to an embodiment of the present invention.

[0023] Figure 6 It is a schematic structural diagram of a composite fiber collimator according to an embodiment of the present invention.

[0024] Figure 7 It is a schematic diagram of a composite photodiode according to an embodiment of the present invention.

[0025] Figure 8 It is a schematic flowchart of a method according to an embodiment of the present invention.

[0026] Figure 9 It is a schematic diagram of the temperature rise process of a lithium-ion battery according to an embodiment of the present invention.

[0027] Figure 10 It is a schematic diagram of the radiation light before and in the initial stage of a lithium-ion battery failure according to an embodiment of the present invention.

[0028] Figure 11 It is a schematic diagram of the radiation light in the middle and late stages of a lithium-ion battery failure according to an embodiment of the present invention.

[0029] In the figure: 100, composite fluorescent optical fiber; 101, fluorescent outer cladding; 102, first fluorescent optical fiber; 103, fluorescent isolation layer; 104, second fluorescent optical fiber; 201, first optical fiber interface; 202, second optical fiber interface; 203, penetrator body; 204, central lens; 2041, outer embedded layer; 2042, outer lens layer; 2043, isolation layer; 2044, inner lens layer; 300, composite quartz optical fiber; 301, quartz outer cladding; 302, first quartz optical fiber; 303, quartz isolation layer; 304, second quartz optical fiber; 400, composite fiber collimator; 401, collimation outer layer; 402, collimation inner layer; 501, collimation outer layer photosensitive area; 502, collimation inner layer photosensitive area; 600, cell outer wall. Detailed implementation manners

[0030] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0032] The present invention provides a lithium-ion battery state monitoring device based on a composite element, comprising: An infrared laser emitter, which is arranged inside the lithium-ion battery core and is used to irradiate the electrolyte inside the lithium-ion battery core to generate a reflected optical signal. A composite fluorescent optical fiber 100, which is arranged inside the battery core and is used to collect the radiation optical signal generated by an abnormal power generation reaction inside the lithium-ion battery core and the reflected optical signal generated by a temperature change caused by an abnormal chemical reaction. A composite optical fiber penetrator, which is arranged inside the lithium-ion battery core, and the composite fluorescent optical fiber 100 is connected to the first end of the composite optical fiber penetrator and is used to transmit the radiation optical signal and the reflected optical signal collected by the composite fluorescent optical fiber 100 inside the lithium-ion battery core to the outside of the lithium-ion battery core. A composite quartz optical fiber 300, which is arranged outside the lithium-ion battery core, and the first end of the composite quartz optical fiber 300 is connected to the second end of the composite optical fiber penetrator and is used to transmit the optical signal. A composite optical fiber collimator 400, which is connected to the second end of the composite quartz optical fiber 300 and is used to convert the optical signal in the composite quartz optical fiber 300 into two parallel optical signals with uniform distribution. A composite photodiode, which is connected to the composite optical fiber collimator 400 and is used to detect the collimated optical signal.

[0033] In an implementable embodiment, as Figure 1As shown in the figure, the composite fluorescent optical fiber 100 includes, from outside to inside, a fluorescent outer cladding 101, a first fluorescent optical fiber 102, a fluorescent isolation layer, and a second fluorescent optical fiber 103. The fluorescent outer cladding 101 is made of a transparent anti-corrosion material. The fluorescent outer cladding 101 includes an outer side and an inner side of the fluorescent outer cladding 101. The laser generated by the infrared laser emitter can only enter the inner side of the fluorescent outer cladding 101 from the outer side of the fluorescent outer cladding 101. The first fluorescent optical fiber 102 is used to collect the radiation optical signals generated inside the lithium-ion battery core due to abnormal power generation reactions or abnormal chemical reactions. The second fluorescent optical fiber 103 of the composite fluorescent optical fiber 100 is used to collect the reflected optical signals generated by the temperature change inside the lithium-ion battery core due to abnormal chemical reactions. The fluorescent isolation layer includes an outer side and an inner side of the fluorescent isolation layer. Both the outer side and the inner side of the fluorescent isolation layer are covered with a high-reflection material or made of a high-reflection material, and are used to isolate the radiation optical signals in the first fluorescent optical fiber 102 from the reflected optical signals in the second fluorescent optical fiber 103, so that the radiation optical signals in the first fluorescent optical fiber 102 are reflected back to the first fluorescent optical fiber 102, and the reflected optical signals in the second fluorescent optical fiber 103 are reflected back to the second fluorescent optical fiber 103.

[0034] Specifically, the composite fluorescent optical fiber 100 is composed of four parts as a whole: Outer cladding: The outer cladding is made of a transparent anti-corrosion material. On the one hand, it can adapt to the acidic and alkaline environments inside the lithium-ion battery; on the other hand, it is convenient for the radiation optical signals of abnormal chemical reactions or abnormal discharges inside the lithium-ion battery to enter the first fluorescent optical fiber 102 through the outer cladding. At the same time, the inner side of the outer cladding is specially treated to only allow light to enter from the outer side to the inner side, and can reflect the optical signals on the inner side as much as possible.

[0035] First fluorescent optical fiber 102 area: The first fluorescent optical fiber 102 is mainly used to collect the photons radiated by abnormal discharges or abnormal chemical reactions inside the lithium-ion battery. The first fluorescent optical fiber 102 is doped with a fluorescent material in the wavelength range of 200 - 1000 nm, can effectively collect optical signals in the ultraviolet to near-infrared wavelength range, and amplifies and converts the optical signals in this wavelength range to a wavelength range matching the subsequent optoelectronic conversion device through the side-light input method.

[0036] Isolation layer: The function of the isolation layer is to isolate the first fluorescent optical fiber 102 area and the second fluorescent optical fiber 103 area. Its thickness requirement is relatively low, but both sides are made of a material with a high reflectivity or covered with a coating of a high-reflection material, so that the optical signals in the first fluorescent optical fiber 102 area can be reflected back to the first fluorescent optical fiber 102 area, and the optical signals in the second fluorescent optical fiber 103 area can be reflected back to the second fluorescent optical fiber 103 area, while realizing area isolation.

[0037] Second Fluorescent Optical Fiber 103 Region: The second fluorescent optical fiber 103 is mainly used to collect the reflected infrared signals that change due to temperature changes inside the lithium-ion battery. The source of the infrared signals is the light source module placed inside the battery cell, such as devices like lasers or fiber gratings. The currently popular fluorescent optical fiber temperature measurement method is the end-light input mode. Therefore, the composite fluorescent optical fiber 100 can also adopt Figure 2 forms such as the side-light input type composite fluorescent optical fiber 100 shown. The second fluorescent optical fiber 103 is doped with a fluorescent material sensitive to the infrared band of 1000 - 2500 nm, and can effectively collect the optical signals in the infrared band.

[0038] In an implementable embodiment, as Figure 3 shown, the composite optical fiber penetrator includes a first optical fiber interface 201, a second optical fiber interface 202, a penetrator body 203, and a central lens 204. The central lens 204 is embedded in the center of the penetrator body 203. The central lens 204 includes an outer embedded layer 2041, an outer lens layer 2042, an isolation layer, and an inner lens layer 2044. The first optical fiber interface 201 is connected to the composite fluorescent optical fiber 100, the second optical fiber interface 202 is connected to the composite quartz optical fiber 300, and the first optical fiber interface 201 and the second optical fiber interface 202 are ST interfaces and are both provided with sealing devices. The outer embedded layer 2041 is used to tightly fit with the composite optical fiber penetrator and protect the outer lens layer 2042. The outer lens layer 2042 is used to transmit the radiation optical signal collected by the first fluorescent optical fiber 102 of the composite fluorescent optical fiber 100 from inside the lithium-ion battery cell to the first quartz optical fiber 302. The isolation layer is used to isolate the radiation optical signal collected by the first fluorescent optical fiber 102 of the composite fluorescent optical fiber 100 and the reflected optical signal collected by the second fluorescent optical fiber 103 of the composite fluorescent optical fiber 100, preventing the mixing of the radiation optical signal and the reflected optical signal. The inner lens layer 2044 is used to transmit the reflected optical signal collected by the second fluorescent optical fiber 103 of the composite fluorescent optical fiber 100 from inside the lithium-ion battery cell to the second quartz optical fiber 304.

[0039] Specifically, in order to transmit the optical signals captured and converted by the composite fluorescent optical fiber 100 to the outside of the lithium-ion battery cell, a special composite optical fiber penetrator is also required. The appearance structure of the composite optical fiber penetrator is the same as that of an ordinary penetrator, and it is mainly composed of optical fiber interfaces on both sides, a penetrator body 203, and a central lens. The optical fiber interfaces of the penetrator can adopt ST interfaces, and both the inner and outer interfaces are designed with seals on both sides (such as sealing rings, etc.). It is required that the internal and external seals are good, and the penetrator is fixed to the outer wall 600 of the battery cell through threads.

[0040] Different from an ordinary penetrator, the central lens 204 of the composite penetrator is a layered lens, mainly composed of four parts, as Figure 4 shown: Outer embedding layer 2041: The main function of the outer embedding layer 2041 is to firmly embed the composite quartz lens in the center of the penetrator and provide a certain buffer space to protect the lens.

[0041] Outer lens layer 2042: The main function of the outer lens layer 2042 is to transmit the radiation optical signal captured by the first fluorescence optical fiber 102 region for measuring the abnormal optical signal in the composite fluorescence optical fiber 100 to the outside of the lithium-ion battery cell.

[0042] Isolation layer: The main function of the isolation layer is to isolate the optical signal in the first fluorescence optical fiber 102 region from the optical signal in the second fluorescence optical fiber 103 region, lock the optical signal in the first fluorescence optical fiber 102 region in the outer circle of the optical fiber and transmit it out of the lithium-ion battery cell, lock the optical signal in the second fluorescence optical fiber 103 region in the inner circle of the optical fiber and transmit it out of the lithium-ion battery cell, and prevent the quartz lens of the ordinary penetrator from mixing the optical signals in the two regions.

[0043] Inner lens layer 2044: The main function of the inner lens layer 2044 is to transmit the reflected optical signal captured by the second fluorescence optical fiber 103 region for measuring temperature in the composite fluorescence optical fiber 100 to the outside of the lithium-ion battery cell.

[0044] In an implementable embodiment, as Figure 5 shown, the composite quartz optical fiber 300 includes a quartz outer cladding 301, a first quartz optical fiber 302, a second quartz optical fiber 303, and a second quartz optical fiber 304. The quartz outer cladding 301 is an insulating material. The outside of the quartz outer cladding 301 is used to prevent the interference optical signal in the environment from entering the first quartz optical fiber 302, and the inside of the quartz outer cladding 301 is used to reflect the radiation optical signal in the first quartz optical fiber 302 back into the first quartz optical fiber 302. The first quartz optical fiber 302 of the composite quartz optical fiber 300 is used to transmit the radiation optical signal collected by the first fluorescence optical fiber 102 collected by the composite fluorescence optical fiber 100. The second quartz optical fiber 303 of the composite quartz optical fiber 300 is made of a high-reflection material or covered with a high-reflection coating, and is used to reflect the radiation optical signal in the first quartz optical fiber 302 back into the first quartz optical fiber 302, reflect the reflected optical signal in the second quartz optical fiber 304 back into the second quartz optical fiber 304, and isolate the optical signals in the first quartz optical fiber 302 and the second quartz optical fiber to prevent the mixing of the radiation optical signal and the reflected optical signal. The second quartz optical fiber 304 of the composite quartz optical fiber 300 is used to transmit the reflected optical signal collected by the second fluorescence optical fiber 103 collected by the composite fluorescence optical fiber 100.

[0045] Specifically, for the isolated transmission of the optical signal in the first fluorescence optical fiber 102 region and the optical signal in the second fluorescence optical fiber 103 region, the composite quartz optical fiber 300 mainly consists of the following four parts.

[0046] Outer cladding: Different from the outer cladding of the composite fluorescent optical fiber 100, the outer cladding of the composite quartz optical fiber 300 does not use special anti-corrosion and highly transparent materials. However, the outer cladding of the composite fluorescent optical fiber 100 needs to ensure a certain degree of protection and insulation, while isolating the external optical signal from entering the optical fiber. The inner side of its outer cladding is also specially treated to reflect the inner optical signal as much as possible.

[0047] First quartz optical fiber 302: Due to the wide transmission wavelength and low signal transmission attenuation of quartz optical fibers, they can transmit optical signals in the wide wavelength band of 200 - 2500 nm with low attenuation. At the same time, they have excellent light transmission performance and high-temperature stability, thus maintaining high-precision conduction of optical signals and effectively improving the transmission efficiency and reliability of optical signals. Therefore, the present invention uses high-purity quartz optical fibers as the signal transmission channels outside the lithium-ion battery to better transmit the signals to the optoelectronic conversion device. The first quartz optical fiber 302 region mainly transmits the radiation optical signals generated by abnormal chemical reactions or abnormal discharges captured by the fluorescent optical fiber region 1.

[0048] Isolation layer: The function of the isolation layer of the composite fluorescent optical fiber 100 is similar to that of the isolation layer of the composite fluorescent optical fiber 100. It is used to isolate the first quartz optical fiber 302 region and the second quartz optical fiber 304 region. Its thickness requirement is relatively low, but both sides are made of materials with high reflectivity or covered with a coating of high-reflective materials, so that the radiation optical signals in the first quartz optical fiber 302 region can be reflected back to the first quartz optical fiber 302 region, and the reflected optical signals in the second quartz optical fiber 304 region can be reflected back to the second quartz optical fiber 304 region, while achieving regional isolation.

[0049] Second quartz optical fiber 304: The quartz optical fiber material in the second quartz optical fiber 304 region is the same as that in the first quartz optical fiber 302 region. The only difference is that the optical signal transmitted in the second quartz optical fiber 304 region is the reflected optical signal captured by the second fluorescent optical fiber 103 region.

[0050] In an implementable embodiment, as Figure 6 shown, the composite fiber collimator 400 includes a collimation outer layer 401 and a collimation inner layer 402. The collimation outer layer 401 is used to convert the radiation optical signals of the first quartz optical fiber 302 of the composite quartz optical fiber 300 from chaotic optical signals into uniformly distributed parallel optical signals. The collimation inner layer 402 is used to convert the reflected optical signals of the second quartz optical fiber 304 of the composite quartz optical fiber 300 from chaotic optical signals into uniformly distributed parallel optical signals.

[0051] Specifically, the composite fiber collimator contains a collimating lens group composed of a plurality of collimating lenses. Different from ordinary collimators, the lenses in the collimating lens group of the composite fiber collimator are all independent inner and outer double-layer structures that are isolated from each other. The inner collimating layer is used to collimate reflected optical signals, and the outer collimating layer is used to collimate radiation optical signals. The two do not interfere with each other and perform parallel collimation. After the composite isolation optical signal is transmitted through the quartz fiber, the fiber collimator is also required to change the originally crossed or even chaotic optical signals into uniformly distributed parallel light, and finally send it to the photodiode. The advantage of doing this is to avoid the over-concentration or scattering of signal light rays, evenly distribute the signal energy of the optical signal, thereby improving the overall utilization rate of the photosensitive area of the photoelectric converter, avoiding the problem that a small part of the photoelectric converter is saturated while most of it is hardly utilized, and is conducive to the selection and optimization of the photoelectric converter.

[0052] In this application, the fiber collimator adopts a composite structure. The composite fiber collimator is similar to the quartz lens structure of the penetrator, and is divided into an inner collimating layer 402 and the outer side, and collimates the optical signals of the composite quartz fiber 300 in different regions to obtain inner and outer isolated composite parallel light.

[0053] In an implementable embodiment, the outer photosensitive area 501 of the composite photodiode is used to detect the collimated radiation optical signal. The inner photosensitive area 502 of the composite photodiode is used to detect the collimated reflected optical signal.

[0054] Specifically, after the optical signal becomes uniform parallel light through the collimator, it will be projected onto the Figure 7 shown composite photodiode, convert the optical signal into an electrical signal and perform subsequent signal transmission and processing. Different from ordinary photodiodes, the composite photodiode of the present invention has two different photosensitive areas, which respectively detect optical signals of different wavelengths and output two independent electrical signals. Among them, the photosensitive area inside the composite photodiode mainly targets the infrared band reflected optical signal in the area of the second fluorescent fiber 103, and the photosensitive area outside mainly targets the radiation optical signal in the area of the first fluorescent fiber 102.

[0055] The method for monitoring the state of a lithium-ion battery based on composite components provided by the embodiments of the present invention is executed by a computer device. Correspondingly, the system for monitoring the state of a lithium-ion battery based on composite components runs in the computer device.

[0056] For the convenience of understanding the present invention, the principle of the method for monitoring the state of a lithium-ion battery based on composite components of the present invention is used to further describe the method for monitoring the state of a lithium-ion battery based on composite components provided by the present invention.

[0057] Specifically, as Figure 8 shown, the method for monitoring the state of a lithium-ion battery based on composite components includes: S1. The first fluorescent optical fiber and the second fluorescent optical fiber based on the composite fluorescent optical fiber respectively collect the radiation optical signal and the reflected optical signal inside the lithium-ion battery cell.

[0058] S2. The radiation optical signal and the reflected optical signal are respectively transmitted from inside the lithium-ion battery cell to the first quartz optical fiber and the second quartz optical fiber of the composite quartz optical fiber through the outer lens layer and the inner lens layer of the composite optical fiber penetrator.

[0059] S3. The radiation optical signal in the first quartz optical fiber and the reflected optical signal in the second quartz optical fiber are respectively converted into uniformly distributed parallel light through the collimation outer layer and the collimation inner layer of the composite optical fiber collimator.

[0060] S4. The parallel radiation optical signal is projected onto the collimation outer layer photosensitive area of the composite photodiode and converted into a first electrical signal, and the parallel reflected optical signal is projected onto the collimation inner layer photosensitive area of the composite photodiode and converted into a second electrical signal.

[0061] S5. An analog-to-digital converter is used to convert the first electrical signal into a first digital signal and the second electrical signal into a second digital signal, and they are connected to a computer through a signal transmission bus.

[0062] S6. The first digital signal and the second digital signal are input into a pre-established lithium-ion battery fault processing model to determine whether there is an abnormality in the current operating state of the lithium-ion battery. If there is an abnormality, an alarm is issued: Obtain the operating data of the lithium-ion battery from normal operation to the average value of the critical temperature of thermal runaway in the first preset temperature range, and form a first data set. Import the first data set into a pre-established lithium-ion battery thermal runaway simulation model. Through the lithium-ion battery thermal runaway simulation model, obtain the radiation optical and reflected optical data of the average value of the critical temperature of thermal runaway in the second preset temperature range, and form a second data set. Combine the first data set and the second data set, and obtain the radiation optical and reflected optical data of the lithium-ion battery in the full temperature operating range in the first data set and the second data set, and form a third data set. Extract the features of the third data set, and obtain the maximum pulse amplitude of the radiation optical signal, the radiation optical pulse repetition rate, the temperature corresponding to the reflected optical signal, the temperature rise rate corresponding to the reflected optical signal, the waveform similarity and the mutual information coefficient between the reflected optical signal and the radiation optical signal at the same time, and form a first sample set. Intercept the data samples in the first sample set where the temperature is less than the average value of the critical temperature of thermal runaway, and form a second sample set. Perform clustering processing on the second sample set, divide the second sample set into five sets and mark them, and record them as the third sample set, the fourth sample set, the fifth sample set, the sixth sample set and the seventh sample set respectively. Based on the third sample set, the fourth sample set, the fifth sample set, the sixth sample set and the seventh sample set, train a pre-established lithium-ion battery operating state monitoring model to obtain a lithium-ion battery fault processing model.

[0063] If an abnormality exists, an alarm will be given, including: issuing a warning and an alarm sound, activating the self - protection mechanism of the lithium - ion battery, disconnecting the connection between the lithium - ion battery and the outside, and activating the fire - fighting and cooling means.

[0064] Specifically, under normal circumstances, the received radiation light signal by the system remains at a stable 0 level (or due to the overlap of the excitation wavelength bands of the fluorescent optical fiber, the radiation light signal also remains at a certain fixed value); while the electrical signal converted from the reflected light signal fluctuates within the operating range of the lithium - ion battery (typical values such as 0 - 40 °C. For the convenience of description, the temperature rise process will be directly described as follows) Figure 9 The amplitude and rate of the fluctuation are also relatively low, indicating that the lithium - ion battery pack is in a normal operating state at this time, corresponding to Figure 9 the T1 time period.

[0065] When a fault occurs before and during the initial stage of development, the recombination of positive and negative ions inside the battery core will generate radiation and release a certain number of photons of the light - emitting signal. At this time, the electrical signal corresponding to the radiation light will show an impact signal as shown in Figure 10 The amplitudes and periodic repetition rates of these impact signals are usually relatively low, but their reliability and sensitivity are relatively high, and the distinction from the stable electrical signal under normal operating conditions is very obvious, which is sufficient to indicate potential risks.

[0066] And at this time, the temperature corresponding to the reflected light signal gradually rises, and the rising rate is also increasing, as shown in the Figure 9 T2 part.

[0067] At this time, the joint diagnostic system can give an early warning based on the abnormal changes of the light and heat signals, indicating the possible faults. Once the amplitude or repetition rate of any one signal exceeds the preset threshold, the system will automatically activate the protection mechanism, cut off the corresponding battery core or battery compartment, so as to prevent the further deterioration of the accident.

[0068] As shown in Figure 11 When the middle and late stages of the fault occur, the impact amplitude, occurrence frequency and repetition rate of the electrical signal corresponding to the radiation light will all increase sharply. At this time, obvious abnormal chemical reactions or even short - circuit discharges have occurred inside the battery core, causing a certain degree of irreversible damage to the lithium - ion battery.

[0069] And the temperature corresponding to the reflected light rises sharply, as shown in the Figure 9 T3 part. At this time, a thermal runaway phenomenon has occurred, and it is necessary to activate the relay protection and cooling equipment, cut off the power supply of the lithium - ion battery and quickly execute an emergency cooling action.

[0070] Table 1 shows the comparison of typical values of key parameters before and after the fault. Among them, there is often a single pulse with a very large amplitude before and after the fault, and its typical amplitude can reach 1 - 4V.

[0071] Table 1

[0072] Meanwhile, there is a certain correlation between the photothermal signals inside the lithium-ion battery. For example, the occurrence of arc light will bring heat at the same time, causing the temperature of the electrolyte of the lithium-ion battery to rise; and the increase in temperature makes the ion energy increase, making abnormal discharge more likely to occur. The two are mutually causal and have a strong correlation. Therefore, compared with the traditional method of using single reflected light or radiation light as the criterion for judging the operating state of lithium-ion batteries.

[0073] Based on the above battery state monitoring device, a lithium-ion battery fault handling model is established.

[0074] Specifically, it includes steps Q1-Q7: Q1: Pre-collect or obtain through experiments the operating data of the lithium-ion battery in the temperature range from normal operation to the average critical temperature of thermal runaway Tsk - 5°C to form the first data set.

[0075] Q2: Combine the data in the first data set and the average critical temperature of thermal runaway Tsk, and through simulation means or destructive tests, obtain the radiation light and reflected light data in the temperature range after Tsk - 10°C, that is, the second preset temperature range, to form the second data set.

[0076] Q3: Collect the first data set and the second data set, and obtain the radiation light and reflected light data of the lithium-ion battery in the full temperature operating range in the first data set and the second data set to form the third data set.

[0077] Q4: Extract features from the third data set to obtain key state parameters such as the maximum pulse amplitude of radiation light, the pulse repetition rate of radiation light, the temperature corresponding to reflected light, the temperature rise rate corresponding to reflected light, the waveform similarity and mutual information coefficient between reflected light and radiation light signals at the same time to form the first sample set. The sample is denoted as a vector, and the form is as follows: Sample = , , …, where is the i-th key parameter or feature, with a total of N.

[0078] Q5: Intercept the data samples in the first sample set where the temperature is less than the average critical temperature of thermal runaway Tsk to form the second sample set.

[0079] Q6: Perform clustering processing on the second sample set, and divide the second sample set into 5 sets for marking, which are respectively denoted as the third sample set, the fourth sample set, the fifth sample set, the sixth sample set, and the seventh sample set.

[0080] ​The evolved forms after marking are as follows: NewSample = , ,…, K] where K is the mark number, one of the integers from 1 to 5, corresponding to the third to seventh sample sets.

[0081] Q7: Based on the above division of the sample sets, the training of the lithium-ion battery operating state monitoring model is carried out. Among them, the third to seventh sample sets correspond to a total of 5 stages: normal operation stage 1, normal operation stage 2, fault development stage 1, fault development stage 2, and pre-runaway stage. For example, the main characteristics of each stage are as follows: Normal operation stage 1: The temperature of the lithium-ion battery is normal, and there is no obvious discharge phenomenon.

[0082] Normal operation stage 2: The temperature of the lithium-ion battery is normal, and there are occasional local discharge phenomena.

[0083] Fault development stage 1: The temperature of the lithium-ion battery is slightly higher than the normal value, and obvious discharge phenomena occur.

[0084] Fault development stage 2: The temperature of the lithium-ion battery is higher than the normal value, the temperature rise rate is abnormal, and the discharge phenomenon is obvious.

[0085] Pre-runaway stage: The temperature of the lithium-ion battery is close to the thermal runaway temperature, and the internal discharge is intense.

[0086] Specifically, in actual use, the above stages can also be further divided according to the fault situation.

[0087] Q8: For the above 5 stages, corresponding measures are set respectively: Normal operation stage 1: No action.

[0088] Normal operation stage 2: Increase the preset heat exchange value, increase the air intake or increase the coolant circulation rate of the liquid cooling plate.

[0089] Fault development stage 1: Send a prompt signal to indicate that there may be a fault inside the lithium-ion battery, and adjust the air intake and the coolant circulation rate of the liquid cooling plate to the maximum.

[0090] Fault development stage 2: Send a warning, reduce the output current of the lithium-ion battery, and start the auxiliary cooling measures (if any).

[0091] Pre-runaway stage: Send a warning and an alarm sound, start the self-protection mechanism of the lithium-ion battery, disconnect the connection between the lithium-ion battery and the outside; if the temperature of the lithium-ion battery still shows an upward trend within 10s, automatically start the fire-fighting cooling means.

[0092] Therefore, through the composite fluorescent optical fiber, the present invention simultaneously collects the radiation optical signal and the reflected optical signal inside the lithium-ion battery core, and transmits the radiation optical signal and the reflected optical signal to the outside of the lithium-ion battery core through different channels by means of the composite optical fiber penetrator and the composite quartz optical fiber, which can ensure that the signals do not interfere with each other and are transmitted efficiently. The composite optical fiber collimator is used to collimate the radiation optical signal and the reflected optical signal, and the composite photodiode is used to convert the radiation optical signal and the reflected optical signal into electrical signals respectively, so as to realize the independence, integrity and real-time monitoring of the state of the lithium-ion battery. The technical effects that can be achieved in this embodiment can be referred to the description above and will not be elaborated here.

[0093] Those skilled in the art can clearly understand that the technology in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solutions in the embodiments of the present invention, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disc, etc., which can store program codes, including several instructions for causing a computer terminal (which can be a personal computer, a server, or a second terminal, a network terminal, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0094] For the same or similar parts among the various embodiments in this specification, reference can be made to each other. In particular, for the terminal embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description in the method embodiments.

[0095] In several embodiments provided by the present invention, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are only illustrative. For example, the division of the modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of the systems or modules can be in an electrical, mechanical or other forms.

[0096] The module described as a separation component may or may not be physically separated. The component shown as a module may or may not be a physical module, that is, it may be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0097] In addition, in each embodiment of the present invention, the functional modules can be integrated in a processing module, or each module can exist physically alone, or two or more modules can be integrated in one module.

[0098] Although the present invention has been described in detail by referring to the drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should be within the scope of the present invention. / Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A lithium-ion battery status monitoring device based on a composite element, characterized in that: include: An infrared laser transmitter, which is disposed inside the lithium-ion battery cell and is used to irradiate the electrolyte inside the lithium-ion battery cell to generate a reflected light signal; A composite fluorescent optical fiber, which is arranged inside the battery core and is used to collect radiation light signals generated by abnormal power generation reactions inside the lithium-ion battery core and reflected light signals generated by temperature changes caused by abnormal chemical reactions; A composite optical fiber penetrator, the composite optical fiber penetrator is arranged inside the lithium-ion battery core, the composite fluorescent optical fiber is connected to a first end of the composite optical fiber penetrator, and is used to transmit the radiation light signal and the reflection light signal collected by the composite fluorescent optical fiber inside the lithium-ion battery core to the outside of the lithium-ion battery core; A composite quartz optical fiber, wherein the composite quartz optical fiber is arranged outside the lithium-ion battery core, and a first end of the composite quartz optical fiber is connected to a second end of the composite optical fiber through-hole for transmitting an optical signal; A composite optical fiber collimator, which is connected to the second end of the composite quartz optical fiber and is used to convert the optical signal in the composite quartz optical fiber into two parallel optical signals with uniform distribution; The composite photodiode is connected to the composite optical fiber collimator and is used to detect the collimated optical signal.

2. The device according to claim 1, characterized in that The composite fluorescent optical fiber includes, from outside to inside, a fluorescent outer cladding layer, a first fluorescent optical fiber, a fluorescent isolation layer, and a second fluorescent optical fiber; The fluorescent outer cladding layer comprises a transparent anti-corrosion material, the fluorescent outer cladding layer comprises an outer side of the fluorescent outer cladding layer and an inner side of the fluorescent outer cladding layer, and the laser light generated by the infrared laser emitter can only enter the inner side of the fluorescent outer cladding layer from the outer side of the fluorescent outer cladding layer; The first fluorescent optical fiber is used to collect the radiation light signal generated by the abnormal power generation reaction inside the lithium-ion battery core; The second fluorescent optical fiber of the composite fluorescent optical fiber is used to collect the reflected light signal generated by the temperature change caused by the abnormal chemical reaction inside the lithium-ion battery core; The fluorescent isolation layer includes an outer side of the fluorescent isolation layer and an inner side of the fluorescent isolation layer, both of which are covered with or made of high-reflective material, and are used to isolate the radiation light signal in the first fluorescent optical fiber from the reflection light signal in the second fluorescent optical fiber, so that the radiation light signal in the first fluorescent optical fiber is reflected back to the first fluorescent optical fiber, and the reflection light signal in the second fluorescent optical fiber is reflected back to the second fluorescent optical fiber.

3. The device according to claim 1, characterized in that The composite optical fiber through-hole comprises a first optical fiber interface, a second optical fiber interface, a through-hole body and a central lens, wherein the central lens is embedded in the center of the through-hole body, and the central lens comprises an outer embedding layer, an outer lens layer, an isolation layer and an inner lens layer; The first optical fiber interface is connected to a composite fluorescent optical fiber, the second optical fiber interface is connected to a composite quartz optical fiber, the first optical fiber interface and the second optical fiber interface are ST interfaces and are both provided with sealing devices; The outer embedding layer is used to be tightly embedded with the composite optical fiber through-hole and protect the outer lens layer; The outer lens layer is used to transmit the radiation light signal collected by the first fluorescent optical fiber of the composite fluorescent optical fiber to the first quartz optical fiber; The isolation layer is used to isolate the radiation light signal collected by the first fluorescent optical fiber of the composite fluorescent optical fiber and the reflected light signal collected by the second fluorescent optical fiber of the composite fluorescent optical fiber, so as to prevent the radiation light signal and the reflected light signal from mixing; The inner lens layer is used to transmit the reflected light signal collected by the second fluorescent optical fiber of the composite fluorescent optical fiber to the second quartz optical fiber.

4. The device according to claim 1, characterized in that The composite quartz optical fiber includes, from outside to inside, a quartz outer cladding, a first quartz optical fiber, a quartz isolation layer and a second quartz optical fiber; The quartz outer cladding is an insulating material, the outer side of the quartz outer cladding is used to prevent interference light signals in the environment from entering the first quartz optical fiber, and the inner side of the quartz outer cladding is used to reflect the radiation light signal in the first quartz optical fiber back to the first quartz optical fiber; The first quartz optical fiber of the composite quartz optical fiber is used to transmit the radiation light signal collected by the first fluorescent optical fiber collected by the composite fluorescent optical fiber; The quartz isolation layer of the composite quartz optical fiber is made of a high-reflection material or covered by a high-reflection coating, and is used to reflect the radiated light signal in the first quartz optical fiber back to the first quartz optical fiber, reflect the reflected light signal in the second quartz optical fiber back to the second quartz optical fiber, and isolate the light signals in the first quartz optical fiber and the second quartz optical fiber to prevent the mixing of the radiated light signal and the reflected light signal; The second quartz optical fiber of the composite quartz optical fiber is used to transmit the reflected light signal collected by the second fluorescent optical fiber collected by the composite fluorescent optical fiber.

5. The device according to claim 1, characterized in that The composite optical fiber collimator comprises a collimating outer layer and a collimating inner layer; The collimating outer layer is used to convert the radiation light signal of the first quartz optical fiber of the composite quartz optical fiber into a uniformly distributed radiation light signal; The collimating inner layer is used to convert the reflected light signal of the second quartz optical fiber of the composite quartz optical fiber into a reflected light signal with uniform distribution.

6. The device according to claim 1, characterized in that The composite photodiode comprises a collimated outer photosensitive region and a collimated inner photosensitive region; The collimated outer photosensitive area is used to detect the collimated radiation light signal; The collimated inner layer photosensitive area is used to detect the collimated reflected light signal.

7. The device according to any one of claims 2 to 6, characterized in that: The wavelength band of the radiated light signal includes 200-1000nm; The wavelength band of the reflected light signal includes 1000-2500nm.

8. A lithium-ion battery state monitoring method based on a composite element, characterized in that: include: The first fluorescent optical fiber and the second fluorescent optical fiber based on the composite fluorescent optical fiber respectively collect the radiation light signal and the reflection light signal inside the lithium-ion battery cell; The radiation light signal and the reflection light signal are transmitted from the inside of the lithium-ion battery cell to the first quartz optical fiber and the second quartz optical fiber of the composite quartz optical fiber through the outer lens layer and the inner lens layer of the composite optical fiber through the inside of the lithium-ion battery cell; The radiation light signal in the first quartz optical fiber and the reflected light signal in the second quartz optical fiber are respectively converted into uniformly distributed parallel light through the collimation outer layer and the collimation inner layer of the composite optical fiber collimator; Projecting the parallel radiation light signal to the collimated outer photosensitive area of ​​the composite photodiode and converting it into a first electrical signal, and projecting the parallel reflection light signal to the collimated inner photosensitive area of ​​the composite photodiode and converting it into a second electrical signal; Using an analog-to-digital converter to convert the first electrical signal into a first digital signal, and convert the second electrical signal into a second digital signal, and connecting the signals to a computer via a signal transmission bus; The first digital signal and the second digital signal are input into a pre-established lithium-ion battery fault processing model to determine whether there is an abnormality in the current lithium-ion battery operating state. If there is an abnormality, an alarm is issued.

9. The method according to claim 8, characterized in that Inputting the first digital signal and the second digital signal into a pre-established lithium-ion battery fault processing model to determine whether the current lithium-ion battery operating state is abnormal includes: Acquire operation data of the lithium-ion battery from normal operation to an average value of a critical temperature of thermal runaway in a first preset temperature range to form a first data set; Importing the first data set into a pre-established lithium-ion battery thermal runaway simulation model, and obtaining radiated light and reflected light data of the average value of the thermal runaway critical temperature within a second preset temperature range through the lithium-ion battery thermal runaway simulation model to form a second data set; The first data set and the second data set are collected, and the radiated light and reflected light data of the lithium-ion battery in the full temperature operation range are obtained from the first data set and the second data set to form a third data set; Performing feature extraction on the third data set to obtain the maximum pulse amplitude of the radiated light, the pulse repetition rate of the radiated light, the temperature corresponding to the reflected light, the temperature rise rate corresponding to the reflected light, the waveform similarity of the reflected light and the radiated light signal, and the mutual information coefficient at the same time to form a first sample set; Intercept data samples in the first sample set whose temperature is less than the average value of the critical temperature of thermal runaway to form a second sample set; Performing clustering processing on the second sample set, dividing the second sample set into 5 sets and marking them, which are respectively recorded as the third sample set, the fourth sample set, the fifth sample set, the sixth sample set and the seventh sample set; Based on the third sample set, the fourth sample set, the fifth sample set, the sixth sample set and the seventh sample set, a pre-established lithium-ion battery operation status monitoring model is trained to obtain a lithium-ion battery fault processing model.

10. The method according to claim 8, characterized in that If there is an abnormality, an alarm will be issued, including: A warning and alarm sound is issued, the self-protection mechanism of the lithium-ion battery is activated, the connection between the lithium-ion battery and the outside is disconnected, and the fire-fighting cooling means are activated.

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