Two-way response anti-interference gas detection method and lithium battery thermal runaway early warning device
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN UNIV
- Filing Date
- 2026-03-27
- Publication Date
- 2026-06-12
Smart Images
Figure CN122193316A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of gas sensors, specifically relating to a bidirectional response anti-interference gas detection method and a lithium battery thermal runaway early warning device. Background Technology
[0002] Thermal runaway is the most serious form of safety accident in lithium-ion batteries. Its early stages are often accompanied by the release of specific characteristic gases, mainly including carbon monoxide, ethylene, and hydrogen. Therefore, monitoring the composition and concentration of these characteristic gases to achieve early warning of thermal runaway is of great significance for protecting life and property.
[0003] However, existing gas detection technologies face severe challenges of "cross-interference" in practical applications. Traditional semiconductor gas sensors (such as metal-oxide-semiconductor (MOS) sensors and conventional two-dimensional material sensors) are typically broad-spectrum response devices. This means that a single sensor often responds to multiple reducing gases. For example, a sensor designed to detect CO will usually also produce significant electrical signal changes in response to ethylene, hydrogen, and other gases.
[0004] More critically, existing sensor array (electronic nose) designs face a mathematical "ill-conditioned solution" dilemma. Most traditional gas-sensitive materials exhibit a single polarity in their electrical signal changes (e.g., a decrease in resistance or work function) when exposed to reducing gases. That is, all sensors show a "unidirectional response" to all target gases (e.g., all coefficients are positive). When constructing sensor arrays to calculate mixed gas concentrations, this single polarity leads to extremely strong linear correlations between the row vectors in the response matrix, resulting in a very large condition number—a typical ill-conditioned matrix. In this situation, minute measurement noise is amplified into huge computational errors, making it impossible for the system to accurately distinguish between "high-concentration weak-response gases" and "low-concentration strong-response gases," easily leading to false alarms or missed alarms, and failing to meet the high reliability requirements of battery safety warnings.
[0005] Although theoretical studies have calculated the gas-sensitive properties of transition metal-doped black phosphorus (BP) materials based on density functional theory (DFT), revealing that certain doped materials have special adsorption energies and charge transfer characteristics for different gases, existing technologies have not fully utilized these physical properties at the system algorithm level to solve the aforementioned "ill-conditioned matrix" problem. There is a lack of a system-level technical solution that can transform the microscopic physical mechanism of materials into macroscopic anti-interference capabilities. Summary of the Invention
[0006] To overcome the shortcomings of existing gas sensor arrays in processing mixed gases, such as severe cross-interference and ill-conditioned solution matrices, this invention provides a bidirectional response anti-interference gas detection method and a lithium battery thermal runaway early warning device. By introducing a physical layer of "positive and negative" response characteristics, a low condition number differential response matrix is constructed. The matrix structure can effectively suppress small disturbances in the input signal, thereby solving the problem of solution divergence caused by cross-interference in mixed gas detection without the need for complex physical preprocessing.
[0007] According to one aspect of the present invention, a bidirectional response anti-interference gas detection method is provided, comprising: Acquire the real-time response signal of the gas sensor array in the environment under test; the gas sensor array includes at least one first sensing unit and one second sensing unit, wherein the first sensing unit and the second sensing unit have different gas-sensitive response polarities for the first type of target gas and the second type of target gas, wherein the gas-sensitive response polarity refers to the direction of the resistance value change of the sensing unit after contacting the target gas. Based on a pre-defined response characteristic model, the response matrix is constructed using the polarity difference between positive and negative electrical responses and the real-time response signal. Perform inverse operations and / or pattern matching on the response matrix to output the target gas composition and concentration information in the environment under test.
[0008] As a further technical solution, the first sensing unit uses a gas-sensitive material with different response polarities to the first type of target gas and the second type of target gas; the second sensing unit uses a gas-sensitive material with the same response polarity to the first type of target gas and the second type of target gas.
[0009] As a further technical solution, the first sensing unit uses black phosphorus material doped with transition metal as the sensing element, which generates a positive electrical response to the first type of target gas and a negative electrical response to the second type of target gas.
[0010] As a further technical solution, a positive electrical response refers to the increase in the work function of the gas-sensitive material caused by gas adsorption, while a negative electrical response refers to the decrease in the work function of the gas-sensitive material caused by gas adsorption.
[0011] As a further technical solution, the response matrix introduces coefficients with opposite signs, making it a non-singular matrix.
[0012] As a further technical solution, the mathematical form of the response matrix is as follows: ; in, , These are the response signals of the first and second sensing units, respectively; , These are the concentrations of the first and second type of target gases, respectively. This represents the response coefficient value of the first sensing unit to the first type of target gas. This represents the response coefficient value of the second sensing unit to the first type of target gas. For the introduced coefficients with opposite signs; This represents the response coefficient value of the first sensing unit to the second type of target gas. This represents the response coefficient value of the second sensing unit to the second type of target gas.
[0013] According to another aspect of this specification, a lithium-ion battery thermal runaway early warning device is provided, comprising: A gas sensor array comprising at least two sensing channels with different gas-sensitive response polarities; A signal conditioning circuit is used to acquire analog signals from the sensor array and convert them into digital signals; A processor, which stores a computer program, which, when executed by the processor, implements a bidirectional response anti-interference gas detection method based on the digital signal output by the signal conditioning circuit. The alarm module is used to trigger graded early warnings based on the gas composition and concentration information output by the processor.
[0014] As a further technical solution, the sensing channels with different gas-sensitive response polarities include at least one first sensing unit channel and one second sensing unit channel, wherein the first sensing unit and the second sensing unit have different gas-sensitive response polarities for the first type of target gas and the second type of target gas.
[0015] As a further technical solution, the gas sensor array includes at least one first sensing unit with strong adsorption properties for characteristic gases in the early stage of thermal runaway of lithium-ion batteries. The first sensing unit is designed as a disposable fusible probe to capture characteristic gas fingerprint signals in the early stage of thermal runaway of lithium-ion batteries.
[0016] As a further technical solution, the characteristic gases in the early stages of thermal runaway of lithium-ion batteries include, but are not limited to, carbon monoxide, ethylene, hydrogen and / or carbon dioxide.
[0017] Compared with existing technologies, the advantages of this invention are as follows: It significantly improves the algorithm's tolerance to interfering gases. This invention constructs a low-condition-number differential response matrix by introducing a physical "positive and negative" response characteristic. Compared with traditional methods, this matrix structure can effectively suppress small disturbances in the input signal. For weak background signals generated by non-target gases, the system treats them as tolerable measurement noise and mathematically suppresses them, thus solving the problem of solution divergence caused by cross-interference in mixed gas detection without complex physical preprocessing.
[0018] It achieves highly reliable "differential fingerprint" identification: by combining the rise and fall of signals ("one rise and one fall" and "both fall"), it can quickly and qualitatively distinguish between target gas and interfering gas, eliminating the risk of false alarms caused by signal ambiguity and superposition in traditional methods.
[0019] It specifically addresses the pain point of thermal runaway early warning: by utilizing the strong adsorption properties of the first gas-sensitive material for abnormal gases as an "electronic fuse," it ensures that the alarm signal is absolutely reliable and will not be lost at the critical moment when battery thermal runaway occurs. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 A flowchart illustrating a bidirectional response anti-interference gas detection method provided by the present invention; Figure 2 In this embodiment of the invention, the first sensing unit (Pt-BP) and the second sensing unit (Ag-BP) are sensitive to different gases (CO / The change in the work function of ) Comparison diagram; Figure 3 This is a simulation comparison of the solution error of the differential response matrix constructed in this invention and the traditional all-positive response matrix under different noise levels; Figure 4 In the embodiments of the present invention, CO and Schematic diagram of the microscopic competitive adsorption geometry on the Pt-BP surface; Figure 5 In the embodiments of the present invention, CO and Figure showing the average electrostatic potential distribution and work function calculation results of the co-adsorption system along the direction perpendicular to the surface; Figure 6 This is an average electrostatic potential distribution diagram of a clean Pt-BP surface in an embodiment of the present invention; Figure 7 This is a schematic diagram of the fast qualitative identification logic based on signal polarity features in an embodiment of the present invention; Figure 8 This is a schematic diagram of a lithium-ion battery thermal runaway early warning device provided by the present invention. Detailed Implementation
[0022] It should be noted that: The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0023] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.
[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.
[0025] like Figure 1 As shown, a bidirectional response anti-interference gas detection method includes: Step 1: Acquire the real-time response signal of the gas sensor array in the environment to be tested; the gas sensor array includes at least one first sensing unit and one second sensing unit, wherein the first sensing unit and the second sensing unit have different gas-sensing response polarities for the first type of target gas and the second type of target gas. Step 2: Based on the preset response characteristic model, utilize the polarity difference between the positive and negative electrical responses to construct a response matrix using the real-time response signal; Step 3: Perform inverse calculation and / or pattern matching on the response matrix to output the target gas composition and concentration information in the environment under test.
[0026] The gas-sensitive response polarity refers to the direction of the resistance change of the sensing unit after it comes into contact with the target gas. Specifically, this change in resistance is essentially caused by charge transfer in the gas-sensitive material due to gas adsorption, which in turn leads to an increase or decrease in the macroscopic work function.
[0027] In step 1, the first sensing unit uses a gas-sensitive material with different response polarities to the first type of target gas and the second type of target gas; the second sensing unit uses a gas-sensitive material with the same response polarity to the first type of target gas and the second type of target gas.
[0028] Furthermore, the first sensing unit uses black phosphorus material doped with transition metal as the sensing element, which generates a positive electrical response to the first type of target gas and a negative electrical response to the second type of target gas.
[0029] In this context, the positive electrical response refers to the increase in the work function of the gas-sensitive material due to gas adsorption, while the negative electrical response refers to the decrease in the work function of the gas-sensitive material due to gas adsorption.
[0030] Preferably, for lithium battery scenarios, the first type of target gas is carbon monoxide (CO), and the second type of target gas is ethylene (CO). In this case, the first sensing unit uses a platinum-doped black phosphorus (Pt-BP) sensor. According to theoretical calculations, Pt-BP exhibits an increase in work function (positive response) for CO adsorption and a decrease in work function (negative response) for ethylene adsorption. The second sensing unit uses a silver-doped black phosphorus (Ag-BP) sensor or a palladium-doped black phosphorus (Pd-BP) sensor.
[0031] As a specific implementation method, the present invention provides Embodiment 1: Construction of a sensor array.
[0032] Example 1: A sensor array specifically designed for the characteristic gases in the early stages of thermal runaway in lithium-ion batteries is constructed. The actual data for the work function of the relevant sensing elements are obtained from the paper [1]: Yanetal., Chemical Physics Letters, 2024. The sensor array contains two core sensing channels: Channel A (differential anchor channel, using the first sensing unit): Platinum-doped black phosphorus (Pt-BP) nanomaterials are used as the sensing element. According to density functional theory (DFT) calculations, this material exhibits unique bidirectional electrical response characteristics: when adsorbing carbon monoxide (CO) molecules, its work function... A significant increase (+0.019 eV) was observed, manifested as a positive electrical response (e.g., increased potential); when ethylene ( When the molecule is in the form of a molecule, its work function decreases (-0.136 eV), which manifests as a negative electrical response (such as a decrease in potential). Channel B (auxiliary reference channel, using a second sensing unit): Silver-doped black phosphorus (Ag-BP) nanomaterials are used as the sensing element. This material exhibits a decrease in work function for both carbon monoxide (-0.018 eV) and ethylene (-0.353 eV), meaning the response polarity is consistent and both are negative responses.
[0033] Figure 2 This visually demonstrates the difference in polarity of the responses of the two materials to the two gases. This combination of "one positive and one negative" and "all negative" forms the physical basis of the differential detection in this invention.
[0034] In step 2, the response matrix introduces coefficients with opposite signs, making it a non-singular matrix, with the following mathematical form: ; in, , These are the response signals of the first and second sensing units, respectively; , These are the concentrations of the first and second type of target gases, respectively. This represents the response coefficient value of the first sensing unit to the first type of target gas. This represents the response coefficient value of the second sensing unit to the first type of target gas. For the introduced coefficients with opposite signs; This represents the response coefficient value of the first sensing unit to the second type of target gas. This represents the response coefficient value of the second sensing unit to the second type of target gas.
[0035] The pre-defined response characteristic model utilizes the polarity difference between positive and negative electrical responses, introducing coefficients of opposite signs into the response matrix to construct a non-singular response matrix; this is expressed in the above equation as follows: by introducing negative terms... This significantly increases the linear independence between the row vectors of the response matrix, reduces the condition number of the matrix, and thus suppresses the influence of measurement noise on concentration calculation.
[0036] As a specific implementation method, the present invention provides Embodiment 2: a solution method based on the difference response matrix.
[0037] Example 2 details how to construct a non-singular matrix using the aforementioned physical properties to solve ill-conditioned computation problems, and verifies the effectiveness of the method through multi-dimensional simulations, including: 1. Construction of the theoretical model: It is assumed that CO (concentration) exists in the environment to be tested. ) and ethylene (concentration) The linear response model of the sensor array can be expressed as:
[0038] in, The sensor response value. This represents the response value of the first sensing unit. This is the response value of the second sensing unit; , , and For the corresponding , , , The response coefficient.
[0039] In traditional techniques, because the response direction of materials to reducing gases is usually the same (e.g., all negative), the response coefficients are all of the same sign. In this case, if the selectivity of two sensors to the gas is not significantly different (i.e.,...),... If the determinant of the coefficient matrix approaches zero, the matrix becomes ill-conditioned, and the solution becomes extremely unstable.
[0040] In this invention, a sign difference in the physical layer is introduced: (Pt versus CO) is positive (+), let its absolute value be... ; (Pt versus ethylene) is negative (-), let its absolute value be... ; (Ag versus CO) is negative (-), let its absolute value be... ; (Ag versus ethylene) is a negative value (-), let its absolute value be... Substituting into the system of equations, the resulting response matrix is:
[0041] Calculate the determinant of the matrix. :
[0042] Therefore, the absolute value of a determinant is formed by the sum of two positive numbers, which makes... Significantly far from zero, ensuring the non-singularity of the matrix.
[0043] This nonsingular matrix, constructed based on positive and negative bidirectional responses, exhibits extremely strong robustness when dealing with interference from non-target gases (such as hydrogen).
[0044] In actual testing, interfering gases such as hydrogen may generate weak additional signals on the sensor. In traditional co-response matrices, due to the extremely large matrix condition number, tiny... This will be significantly amplified during the inverse operation, resulting in a huge deviation in the calculated concentration value.
[0045] In the response matrix constructed in this embodiment, due to the introduction of coefficients with opposite signs ( For positive, (Negative), the row vectors of the matrix exhibit a significant orthogonal trend, and the condition number is greatly reduced. This means that the system has extremely high "fault tolerance": even if the sensor signal is superimposed with background interference caused by hydrogen gas. This "additive noise" does not significantly alter the solution space of the equation system. Therefore, this method does not require the design of additional physical filtration devices for hydrogen; it can suppress the influence of hydrogen interference on concentration calculation at the mathematical level solely through matrix operations, achieving algorithm-level anti-interference.
[0046] The robustness of the model will be verified through mathematical simulation, and the effectiveness of the simulation will be verified through physical simulation.
[0047] 2. Mathematical simulation verification of algorithm robustness: In order to quantitatively verify the solution stability of the above difference response matrix under strong noise and interference environment, Monte Carlo numerical simulation was performed using MATLAB.
[0048] Simulation settings: Set the response matrix of this invention. :
[0049] (in The first row is numerically a Pt-BP pair and The values of the work function, the second row shows the values of Ag-BP pairs respectively. and The condition number of the work function is approximately 4.8 (well-behaved). Simultaneously construct a traditional same-direction response matrix As a control, its condition number exceeds 85 (ill-conditioned):
[0050] (in The first row of values represents Ag-BP pairs. and The first line shows the value of the work function; the second line shows the simulation values that are highly similar to the Ag-BP response to the two gases, given by the simulation of the real situation using the traditional unidirectional response matrix. This is intended to reproduce the strong collinearity problem common in traditional sensor arrays, thereby demonstrating the advantage of the algorithm of this invention in solving such ill-conditioned problems. The second line is the corresponding condition number, which exceeds 85 (ill-conditioned).
[0051] Simulation process: Multiple measurement noise levels were set within the range of 0% to 10%. The "noise" set here has a dual physical meaning: first, the thermal noise of the sensor's own circuitry; second, based on the above physical simulation conclusions, the slight signal deviation (<1%) caused by the co-adsorption of non-target gases such as hydrogen. Random noise conforming to a standard normal distribution was superimposed on the theoretical signal to simulate the above mixed interference environment, and the gas concentration was inverted using matrix inverse operations.
[0052] Verification results: such as Figure 4 As shown, with increasing noise levels, the solution error of the control group increases exponentially (see Comparative Example 1), exceeding 25% at 1% noise. In contrast, the solution error of this invention increases extremely slowly, remaining below 8% even under 10% strong noise interference. This result strongly demonstrates the superiority of the differential algorithm: thanks to the well-conditioned matrix structure, this method can effectively suppress signal deviations generated by interfering gases such as hydrogen as ordinary measurement noise, thereby avoiding the "interference amplification" effect caused by the ill-conditioned matrix of traditional co-directional response arrays.
[0053] 3. Physical simulation verification of the microscopic anti-interference mechanism: Another core assumption of this method is Although non-target gases may have physical contact, their generated electrical signal responses are weak and can be considered background noise that is filtered out by the algorithm. To verify the rigor of this assumption, this embodiment uses a first-principles calculation method based on density functional theory (DFT) to perform atomic-scale competitive adsorption simulation.
[0054] 1) Model building and parameter setting: A Pt-modified black phosphorus (Pt-BP) monolayer surface model was constructed, and a target gas (CO) and a disruptive gas (CO) were simultaneously introduced above the Pt active sites. This study simulates the mixed competitive adsorption environment in the early stages of thermal runaway. The GGA-PBE functional was used for calculations, employing the DNP4.4 dual numerical basis set. DSPP half-nuclear pseudopotentials and DFT-D dispersion correction were introduced to ensure computational accuracy.
[0055] 2) Geometric structure verification (see the instruction manual appendix) Figure 5 , 6 ): Geometric optimization results show that Pt atoms exhibit dual adsorption characteristics for both gases in this microscopic co-adsorption system. Specifically, CO molecules are adsorbed vertically at their C-termini, forming a C-Pt chemical bond with a bond length of approximately 1.85 Å. Although the molecule also undergoes adsorption (H-Pt bond length is about 1.76 Å), its spatial configuration shows weak lateral adsorption.
[0056] 3) Work function and electronic property analysis (see appendix of the instruction manual) Figure 5 (Introducing target gas and interfering gas). Figure 6 (Clean surface) Despite the geometric structure showing Adsorption is present, but electronic property analysis indicates that the changes in the sensor's electrical signal are primarily driven by the more polar CO molecules. Specific calculation data are as follows: Reference value: The calculated work function of a clean Pt-BP surface is 5.279 eV.
[0057] Theoretical signal value: Based on the strong polarity of CO, the work function of Pt-BP adsorbing CO alone is estimated to be approximately 4.821 eV (corresponding to the change in effective signal). ).
[0058] Actual interference value: in CO and In the coexisting mixed system, the absolute work function calculated using first-principles calculations is 4.816 eV. The total change relative to the clean surface is... It is approximately -0.463 eV.
[0059] 4) Data Comparison Conclusion: Comparing the above data, it was found that even with the introduction of interfering gases... The work function of the mixed system deviates from that of the pure target gas system by only 0.005 eV (relative deviation rate <0.2%). This tiny deviation confirms the microscopic mechanism of this invention: the significant dipole moment of CO molecules induces a large transfer of surface charge, establishing the potential reference of the system; while As a nonpolar molecule, even if chemisorption occurs, its impact on the surface Fermi level is negligible. This physical characteristic of "signal insensitivity" provides a solid physical basis for simplifying hydrogen interference into "filterable additive low-amplitude noise" in the above mathematical simulation.
[0060] Comparative Example 1: Comparison of the solution performance of a traditional in-direction response array. To further verify the advantages of this invention, a traditional sensor array was constructed as a control group (corresponding to...). Figure 3 (The data is represented by dashed lines). This control group array contains: 1. Sensor A': Silver-doped black phosphorus (Ag-BP); 2. Sensor B': A simulated gas-sensitive material with unidirectional response characteristics. (Since other materials mentioned in the paper [1], such as Pd-BP, actually have excellent positive and negative bidirectional response characteristics, which do not conform to the disadvantage of "traditional unidirectional response", sensor B' is constructed using numerical simulation. Its parameters simulate a traditional material that produces negative responses to both CO and ethylene, and whose response ratio is highly similar to Ag-BP, aiming to reproduce extreme cross-interference conditions). The constructed response matrix The format is as follows: (Consistent with the control group data in Example 2) Because all coefficients have the same sign, and the adsorption selectivity of different materials for the two reducing gases varies only slightly, the two row vectors of the matrix are highly linearly correlated. Calculations show that the condition number of this control group matrix is over 85, classifying it as a severely ill-conditioned matrix.
[0061] Substitute the same concentration data into the solution, and add 0%-10% random measurement noise. The simulation results are as follows. Figure 3 As shown by the dashed line, the solution error of the control group (traditional all-positive / all-negative matrix) increases exponentially with increasing noise levels. Even with only 1% noise, the relative error in concentration calculation exceeds 25%, rendering it completely useless. This indicates that traditional co-directional response arrays suffer catastrophic solution failure when faced with weak interference in real-world environments.
[0062] In contrast, the embodiments of the present invention ( Figure 3 (Solid line) By introducing positive and negative coefficients, the matrix condition number is reduced to below 10. Under strong noise interference of 10%, the solution error is still controlled at around 8%, which proves the significant advantage of the "differential fingerprint" design paradigm in anti-interference.
[0063] As a supplementary explanation, the introduction of the opposite-sign coefficient is not a purely mathematical assumption; it is feasible at the physical level and is based on a direct reflection of the microscopic physical properties of the material. This is discussed in the aforementioned embodiments and physical simulation sections (…). Figure 2 , Figure 5 Evidence already exists supporting the conclusion that the work function of Pt-BP significantly increases (corresponding to a positive coefficient) during CO adsorption, while adsorption... The work function decreases (corresponding to a negative coefficient). The coefficients with opposite signs in the matrix are the mathematical expression of this macroscopic electrical signal "rise and fall" physical phenomenon. That is, the coefficients with opposite signs are determined by the physical difference in the direction of charge transfer on the material surface caused by the target gas.
[0064] Preferably, the method further includes a rapid qualitative identification logic: When the signal of the first sensing unit rises and the signal of the second sensing unit falls, it is determined that the first type of target gas mainly exists in the environment under test. When a decrease in the signal of the first sensing unit and a decrease in the signal of the second sensing unit are detected, it is determined that the second type of target gas mainly exists in the environment under test.
[0065] As a specific implementation method, the present invention provides Embodiment 3: Fast identification logic based on polarity features: For embedded early warning terminals with limited computing resources, this invention also provides a fast qualitative identification method that does not require complex matrix operations, the logic of which is as follows: Figure 7 As shown: Real-time acquisition of response signal from channel A (first sensing unit channel) ) and Channel B (response information of the second sensing unit channel) The signal change trend.
[0066] Perform logical judgment: If It shows a significant upward trend (+), and If the trend shows a downward trend (-), the system determines that the main gas is carbon monoxide (CO) and triggers the corresponding level of warning; if It shows a significant downward trend (-), and The system shows a downward trend (-), and determines that the current main gas is ethylene ( This usually corresponds to the SEI film decomposition stage of the battery, triggering an early warning; if the changes in the two signals are small or the directions do not conform to the above physical laws, the system judges it as background noise or interference and does not issue an alarm.
[0067] Based on the same technical concept as the foregoing embodiments, the present invention provides a lithium-ion battery thermal runaway early warning device, such as... Figure 8 As shown, it includes: A gas sensor array comprising at least two sensing channels with different gas-sensitive response polarities; A signal conditioning circuit is used to acquire analog signals from the sensor array and convert them into digital signals; A processor, which stores a computer program, which, when executed by the processor, implements a bidirectional response anti-interference gas detection method based on the digital signal output by the signal conditioning circuit. The alarm module is used to trigger graded early warnings based on the gas composition and concentration information output by the processor.
[0068] Furthermore, the sensing channels with different gas-sensitive response polarities include at least one first sensing unit channel and one second sensing unit channel, wherein the first sensing unit and the second sensing unit have different gas-sensitive response polarities for the first type of target gas and the second type of target gas.
[0069] Preferably, the gas sensor array includes at least one first sensing unit that has strong adsorption properties for characteristic gases in the early stages of thermal runaway of lithium-ion batteries. The first sensing unit is designed as a disposable fusible probe to capture characteristic gas fingerprint signals in the early stages of thermal runaway of lithium-ion batteries.
[0070] Specifically, the characteristic gases in the early stages of thermal runaway in lithium-ion batteries mainly originate from the decomposition of components such as the solid electrolyte interphase (SEI) film inside the battery during the initial stage of thermal runaway, and the types include, but are not limited to, carbon monoxide, ethylene, hydrogen and / or carbon dioxide.
[0071] As a specific implementation method, this application provides Example 4: Engineering design for strong adsorption properties: According to theoretical calculations, the adsorption energy of Pt-BP material for CO is... Extremely high ( (eV), which means that once CO molecules are adsorbed at room temperature, they are difficult to desorb naturally, leading to sensor "poisoning" or saturation.
[0072] To address this characteristic, this embodiment configures the Pt-BP material sensing unit as a "one-time fuse" or "lock-off" alarm probe. During monitoring, the Ag-BP channel (with moderate adsorption energy and good reversibility) is responsible for daily low-concentration trend monitoring; once the Pt-BP channel detects a characteristic positive signal jump, the system locks into a "thermal runaway level one alarm" state. This state does not depend on the subsequent recovery of the sensor until manual intervention confirms or the probe is replaced. This design utilizes the material's "irreversible" characteristic, transforming it into a "signal lock-in" advantage in safety monitoring, ensuring alarm reliability under extremely dangerous conditions.
[0073] The alarm probe is a targeted hardware supplement. Because Pt-BP has extremely strong CO adsorption (adsorption energy -1.89 eV, which is irreversible adsorption), the sensor itself would be "poisoned" at room temperature. Therefore, it was designed as a disposable fuse-type probe, specifically for capturing deterministic signals in extremely dangerous conditions such as thermal runaway. Once triggered, it physically locks the sensor and does not rely on subsequent algorithms for reset. Routine low-concentration reversible monitoring is handled by the Ag-BP channel.
[0074] In summary, this invention discloses a bidirectional response anti-interference gas detection method and a lithium-ion battery thermal runaway early warning device, belonging to the field of gas sensor technology. Addressing the severe cross-interference and ill-conditioned response matrix problems faced by existing sensor arrays when calculating mixed gases, this invention constructs an array comprising a first sensing unit with bidirectional positive and negative electrical response characteristics and a second sensing unit with unidirectional response. By utilizing the difference in response polarity at the physical level, a non-singular response matrix containing coefficients of opposite signs is constructed, significantly reducing the matrix condition number and transforming ill-conditioned solutions into well-conditioned solutions. This method achieves accurate calculation and rapid identification of thermal runaway characteristic gases such as carbon monoxide and ethylene in high-noise environments, effectively solving the problems of false alarms and missed alarms in early warning systems.
[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.
Claims
1. A bidirectional response anti-interference gas detection method, characterized in that, include: Acquire the real-time response signal of the gas sensor array in the environment under test; The gas sensor array includes at least one first sensing unit and one second sensing unit, wherein the first sensing unit and the second sensing unit have different gas-sensitive response polarities for the first type of target gas and the second type of target gas, wherein the gas-sensitive response polarity refers to the direction of the change in resistance value of the sensing unit after contact with the target gas. Based on a pre-defined response characteristic model, the response matrix is constructed using the polarity difference between positive and negative electrical responses and the real-time response signal. Perform inverse operations and / or pattern matching on the response matrix to output the target gas composition and concentration information in the environment under test.
2. The bidirectional response anti-interference gas detection method according to claim 1, characterized in that, The first sensing unit uses a gas-sensitive material with different response polarities to the first type of target gas and the second type of target gas; the second sensing unit uses a gas-sensitive material with the same response polarity to the first type of target gas and the second type of target gas.
3. The bidirectional response anti-interference gas detection method according to claim 2, characterized in that, The first sensing unit uses black phosphorus material doped with transition metal as the sensing element, which generates a positive electrical response to the first type of target gas and a negative electrical response to the second type of target gas.
4. The gas detection method according to claim 3, characterized in that, The positive electrical response refers to the increase in the work function of the gas-sensitive material caused by gas adsorption, while the negative electrical response refers to the decrease in the work function of the gas-sensitive material caused by gas adsorption.
5. The bidirectional response anti-interference gas detection method according to claim 1, characterized in that, The response matrix incorporates coefficients with opposite signs, making it a non-singular matrix.
6. The bidirectional response anti-interference gas detection method according to claim 5, characterized in that, The mathematical form of the response matrix is as follows: ; in, , These are the response signals of the first and second sensing units, respectively; , These are the concentrations of the first and second type of target gases, respectively. This represents the response coefficient value of the first sensing unit to the first type of target gas. This represents the response coefficient value of the second sensing unit to the first type of target gas. For the introduced coefficients with opposite signs; This represents the response coefficient value of the first sensing unit to the second type of target gas. This represents the response coefficient value of the second sensing unit to the second type of target gas.
7. A lithium-ion battery thermal runaway early warning device, characterized in that, include: A gas sensor array comprising at least two sensing channels with different gas-sensitive response polarities; A signal conditioning circuit is used to acquire analog signals from the sensor array and convert them into digital signals; A processor, wherein a computer program is stored, and when the computer program is executed by the processor, it implements a bidirectional response anti-interference gas detection method as described in any one of claims 1-6 based on the digital signal output by the signal conditioning circuit. The alarm module is used to trigger graded early warnings based on the gas composition and concentration information output by the processor.
8. The lithium-ion battery thermal runaway early warning device according to claim 7, characterized in that, The sensing channels with different gas-sensitive response polarities include at least one first sensing unit channel and one second sensing unit channel, wherein the first sensing unit and the second sensing unit have different gas-sensitive response polarities for the first type of target gas and the second type of target gas.
9. The lithium-ion battery thermal runaway early warning device according to claim 7, characterized in that, The gas sensor array includes at least one first sensing unit that has strong adsorption properties for characteristic gases in the early stages of thermal runaway of lithium-ion batteries. The first sensing unit is designed as a disposable fusible probe to capture characteristic gas fingerprint signals in the early stages of thermal runaway of lithium-ion batteries.
10. The lithium-ion battery thermal runaway early warning device according to claim 9, characterized in that, The characteristic gases in the early stages of thermal runaway of a lithium-ion battery include, but are not limited to, carbon monoxide, ethylene, hydrogen, and / or carbon dioxide.