Intelligent temperature control atmosphere switching crucible for thermal analysis

Abstract

The invention belongs to the field of material thermal analysis technology and precise instrument parts, and particularly relates to an intelligent temperature control atmosphere switching crucible for thermal analysis, and a preparation method of the intelligent temperature control atmosphere switching crucible comprises the following steps: S1, dissolving a polyimide precursor in a mixed solvent of N-methyl pyrrolidone and gamma-butyrolactone in a mass ratio of 7: 3; s2, cooling the mixed system to-20 DEG C, and adding a foaming agent and a cross-linking agent; s3, after the surface modified nanoparticles are added, homogenizing and circulating treatment is carried out for five times under 150 MPa, and the slurry is prepared into a wet film; s4, treating at 80 DEG C for 1 hour, then treating at 120 DEG C for 0.5 hour, and finally treating at 180-300 DEG C for 2 hours; s5, spraying an inorganic barrier coating on the cured PI film; and S6, cutting the composite membrane material to obtain the temperature-sensitive composite sealing cover. The method promotes the progress of a thermal analysis test normal form. According to the method, a traditional static atmosphere test is upgraded into a programmed dynamic atmosphere test, a new way is opened up for researching atmosphere dependent reaction, and the predictive ability and accuracy of a thermal analysis technology in material safety evaluation are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of material thermal analysis technology and precision instrument components, specifically relating to an intelligent temperature-controlled atmosphere switching crucible for thermal analysis. Background Technology

[0002] In the fields of materials research and safety assessment, simulating the dynamic changes in atmosphere that accompany materials during actual failure processes using thermal analysis techniques is crucial. For example, battery thermal runaway often involves a critical transition from gas generation in a closed environment to combustion and explosion in an exposed environment. Accurately reproducing this process is key to assessing the true thermal behavior and risks of materials. However, existing thermal analysis techniques have systematic shortcomings in simulating dynamic atmospheres, leading to test results that deviate from real-world scenarios and limiting their predictive value.

[0003] Traditional thermal analysis methods employ static crucibles, whose atmosphere is preset to be either "always sealed" or "always open," making it impossible to dynamically switch between "sealed and exposed" conditions in situ during a single test. This static simulation is severely disconnected from the complex dynamic processes of reality, making it difficult for the obtained thermal analysis data to accurately reflect the actual reaction characteristics of the material. To overcome this limitation, various schemes attempting to achieve dynamic atmosphere control have emerged during technological development.

[0004] One approach involves introducing an external mechanical device, under program control, to puncture the sealed lid with a puncture needle to achieve atmosphere switching. Taking CN38618573A as an example, the core of this approach is to use an external mechanical device (such as a puncture needle) to puncture the sealed crucible lid at a program-controlled moment to achieve switching from an inert atmosphere to a reactive atmosphere.

[0005] Another approach attempts to trigger the seal by utilizing the material's own physical phase change, such as using a low-melting-point alloy for sealing or a shape memory alloy for actuation. For example, DE102022003789A utilizes a specific alloy melting at a set temperature to achieve seal failure.

[0006] Furthermore, research on temperature-responsive polymers (such as PNIPAm hydrogels) in other fields has also provided insights for the design of smart materials. These explorations mark a technological evolution from static simulation to dynamic control.

[0007] Despite these shortcomings, existing and related technical solutions all have significant drawbacks and cannot meet the testing requirements for high precision and high reliability. Firstly, there are bottlenecks in core performance. Mechanical puncture methods rely on complex peripherals, are not self-triggered, and their operation introduces mechanical vibration and interference, affecting the stability of the heat flow signal. Furthermore, the response speed and opening consistency are limited by mechanical precision. Methods based on material phase changes, such as low-melting-point alloys or shape memory alloys, rely on slow changes in the material state or macroscopic shape for triggering, resulting in slow response speed, low trigger temperature accuracy, and a limited and discrete range of selectable temperature points. Secondly, there is a lack of flexibility and versatility in function and design. The triggering conditions of the above solutions are mostly determined by the fixed physical properties of the materials used, making it difficult to flexibly adjust and program them according to different testing requirements. Thirdly, there is a fundamental contradiction in material integration and processing. If attempts are made to integrate thermosensitive active components such as chemical foaming agents into high-performance polymer matrices such as polyimide to achieve self-triggered functionality, a conflict with the processing temperature window will arise: the high-temperature curing process that ensures polymer performance will prematurely destroy the thermosensitive components, leading to functional failure. Finally, directly borrowing temperature-sensitive material solutions from other fields (such as temperature-sensitive hydrogels) is also not feasible, as they generally suffer from insufficient chemical stability, potential sample contamination, slow volume change rate, unstable performance under thermal analysis testing environments, and difficulty in achieving high-precision mechanical seals.

[0008] In summary, there is an urgent need in the current technological field for a new thermal analysis testing device and method that can achieve rapid, accurate, in-situ, programmable atmosphere switching and is feasible in terms of both materials and processes.

[0009] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0010] This invention belongs to the field of material thermal analysis technology and precision instrument components, specifically relating to an intelligent temperature-controlled atmosphere switching crucible for thermal analysis.

[0011] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing an intelligent temperature-controlled atmosphere switching crucible for thermal analysis, comprising the following steps: S1 polyimide precursor or PES resin is dissolved in a mixed solvent of N-methylpyrrolidone and γ-butyrolactone in a mass ratio of 7:3, wherein the mass ratio of polyimide precursor or PES resin to mixed solvent is 7.5:2.5-3.5. S2 Cool the mixture to -20°C, and add the foaming agent and crosslinking agent under continuous stirring and ultrasonic assistance; After adding 1.0 wt%-4.0 wt% of surface-modified nanoparticles to S3, the slurry was homogenized and cyclically treated 5 times at 150 MPa to prepare a wet film with a thickness of 200±20 μm. S4 is treated at 75-85℃ for 1-1.5 hours to evaporate the solvent, then treated at 115-125℃ for 0.4-0.6 hours to induce initial cyclization of the molecular chains, and finally treated at 180-300℃ for 2 hours to completely imidize the material. The S5 cured PI film is then sprayed with an inorganic barrier coating. The S6 composite membrane is cut to match the size of the crucible body, resulting in a temperature-sensitive composite cap that is detachably sealed to the opening of the crucible body.

[0012] Preferably, the mass ratio of polyimide precursor or PES resin to mixed solvent is 7.5:2.5. Alternatively, the mass ratio of polyimide precursor or PES resin to mixed solvent is 6.5:3.5.

[0013] According to a preferred embodiment, in step S3, 4.0 wt% of surface-modified nanoparticles are added.

[0014] According to a preferred embodiment, in S4, the material is treated at 80°C for 1 hour to evaporate the solvent, then treated at 120°C for 0.5 hours to initially cyclize the molecular chains, and finally treated at 180-300°C for 2 hours to completely imidize the material.

[0015] According to a preferred embodiment, in S4, the processing temperature for fully imidizing the material is 180°C, 185°C, 190°C, 200°C, or 300°C.

[0016] According to a preferred embodiment, the polymer resin is selected from polyimide, biphenyl-type polyimide (BPDA-PI), or polyethersulfone (PES).

[0017] According to a preferred embodiment, the thickness of the inorganic barrier coating is 35-150 nm.

[0018] According to a preferred embodiment, the inorganic barrier coating is an Al2O3 or SiO2 thin film.

[0019] According to a preferred embodiment, the sputtering method is magnetron sputtering deposition.

[0020] According to a preferred embodiment, the surface-modified nanoparticles are surface-vinylened CeO2@SiO2 core-shell nanoparticles.

[0021] One of the objectives of this invention is to provide an intelligent temperature-controlled atmosphere switching crucible for thermal analysis based on the above-described preparation method, which includes a crucible body and a temperature-sensitive composite cap that matches the crucible body and is detachably sealed to the opening of the crucible body.

[0022] One of the objectives of this invention is to provide an application of the intelligent temperature-controlled atmosphere switching crucible for thermal analysis obtained based on the above preparation method in thermal analysis technology simulation experiments.

[0023] According to a preferred embodiment, the thermal analysis simulation experiment is a thermal decomposition simulation experiment of a ternary cathode battery.

[0024] One of the objectives of this invention is to provide a thermal risk assessment method, which includes the following steps: Analyze the thermal decomposition initiation temperature of the material to be tested, and select or customize a crucible cap that matches the trigger temperature T (e.g., within ±5℃). Prepare the experimental materials, place them in the crucible, and cover with a temperature-sensitive composite cap to form an initial seal; The heat flow signal triggered by the temperature-sensitive composite cap opening is collected, and the integral heat release Q per unit mass of sample is calculated.

[0025] A smart temperature-controlled atmosphere switching crucible for thermal analysis, prepared by the above-mentioned method, comprises a crucible body and a temperature-sensitive composite cap that matches the crucible body and is detachably sealed to the opening of the crucible body. The temperature-sensitive composite cap consists of a trigger layer having an inorganic barrier coating, a functional layer having a polymer matrix layer, and a driving layer having a functional foaming layer sequentially arranged in the direction towards the crucible body.

[0026] The beneficial effects of this technical solution are: Firstly, this technical solution achieves a significant leap forward in direct technical performance. Based on the rapid decomposition mechanism of the chemical foaming agent, it achieves a sub-second ultrafast response, with a triggering speed significantly superior to existing solutions that rely on slow physical phase changes or mechanical actions. Simultaneously, through the synergistic design of materials and structure, the control precision of the triggering temperature is improved to within ±1-2℃, enabling more accurate capture of the starting point of the rapid reaction. Regarding sealing reliability, the unique "polymer matrix-dense coating" composite structure achieves an extremely high sealing level before triggering, while after triggering, it enables an instantaneous and substantial jump in leakage rate, thus clearly and reliably completing the atmospheric state switch from "absolute seal" to "fully connected."

[0027] Meanwhile, this technical solution has achieved a key breakthrough in core technology bottlenecks. For the first time, this invention employs a synergistic strategy of "foaming agent compounding - substrate adaptation - coating fine-tuning," enabling a single device to arbitrarily preset and precisely execute triggering within an ultra-wide temperature range, completely solving the problem of fixed and non-programmable trigger temperatures in existing technologies. More importantly, the proposed "function-oriented low-temperature curing process" successfully resolves the inherent contradiction between thermosensitive functional components and high-performance polymer matrices within the processing temperature window, achieving compatibility between function and performance.

[0028] Furthermore, the application value of this invention has been significantly expanded. The "self-triggered" mechanism of the materials used completely avoids external mechanical interference, and for the first time, it achieves dynamic in-situ atmosphere switching synchronized with temperature changes at the millisecond level in thermal analysis, making it possible to realistically simulate dynamic processes such as battery thermal runaway in the laboratory. At the same time, it transforms the complex thermal safety assessment of materials into a standardized and repeatable testing process based on quantitative exothermic criteria, constructing an efficient and objective intelligent platform for material screening and formulation optimization in fields such as solid-state batteries.

[0029] In summary, this invention advances the paradigm of thermal analysis testing. It upgrades traditional static atmosphere testing to programmed dynamic atmosphere testing, opening up new avenues for studying atmosphere-dependent reactions and significantly improving the predictive power and accuracy of thermal analysis technology in materials safety assessment. Attached Figure Description

[0030] Figure 1 This is an exploded structural diagram of the self-triggered crucible involved in the present invention; Figure 2 This is a schematic diagram of the triggering dynamics of the temperature-sensitive composite cap of the self-triggered crucible involved in this invention. Figures a, b, c, and d are schematic diagrams of the sequential changes of the temperature-sensitive composite cap after being triggered. Figure a is a schematic diagram of the principle of the self-triggered opening process of the cap, with the cap intact, without deformation or damage; Figure b is the heating and gas generation state, where the foaming agent decomposes and generates gas upon heating; Figure c is the expansion and pressurization state, where the bottom polymer substrate layer expands synchronously with the expansion, with its outline consistent with the overall arc shape, and the inorganic barrier layer bulges arc-shaped synchronously with the expansion of the substrate, with no cracks or damage on the surface; Figure d is the coating cracking and opening state, where the upper inorganic barrier layer cracks and opens.

[0031] Figure Labels 1: Crucible body; 2: Temperature-sensitive composite cap; 21: Functional foaming layer; 22: Polymer base layer; 23: Inorganic barrier layer. Detailed Implementation

[0032] In the description of this invention, terminology is used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0033] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials, reagents or instruments used, unless otherwise specified by the manufacturer, are all commercially available reagents and materials; the conditions not specified in the examples are all carried out according to conventional conditions or conditions recommended by the manufacturer. At the same time, the present invention does not limit the source of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all commercially available products in this technical field.

[0034] The temperature-sensitive composite cap 2 is composed of three layers of thin films with different functions, arranged from top to bottom (or from outside to inside, with the inside being the side facing the crucible body 1), together achieving the intelligent behavior of "low-temperature sealing and high-temperature self-starting".

[0035] Table 1

[0036] The synergistic triggering principle of the temperature-sensitive composite cap 2 described below is based on the triggering temperature setting. The setting of the triggering temperature (T) is the result of the synergistic effect of the thermodynamics of the foaming agent, the polymer kinetics, and the structural mechanics of the coating.

[0037] Temperature below T (sealed state): The coating provides an ultimate seal (helium leak rate ≤ 1 × 10⁻⁶). -9 Pa·m 3 / s), foaming agent is stable.

[0038] When the temperature is greater than T (trigger opening), such as Figure 2 As shown, the dynamic changes of the temperature-sensitive composite cap 2 are as follows: like Figure 2 a (gas production): When a specific foaming agent reaches its decomposition temperature, it rapidly produces a large amount of gas. like Figure 2 b (Pressure and Deformation): The gas accumulates pressure within the rigid polymer network, driving the matrix to undergo macroscopic volume expansion of ≥35%; like Figure 2 c (Cracking): The stress generated by expansion exceeds the strength limit of the brittle coating, causing it to develop controllable microcracks, achieving "opening" (helium leakage rate jumps to ≥1×10). -4 Pa·m 3 / s). The entire process response time is ≤1 second.

[0039] When designing the temperature-sensitive composite seal 2 for triggering hole opening at different temperatures, a standardized thermal risk assessment of the temperature-sensitive composite seal 2 can be carried out based on the intelligent screening process of the thermal safety of the application method materials of the present invention.

[0040] The evaluation method is as follows: 1. Preliminary matching Analyze the initial decomposition temperature of the material to be tested (such as ternary cathode NCM with different nickel contents).

[0041] According to this temperature, select or customize a temperature-sensitive composite seal 2 with a triggering temperature T matching it (such as within ±5 °C) from the foaming agent library and the matrix-plating matching scheme.

[0042] 2. Standardized test process Sample preparation: In an inert atmosphere glove box, dry mix the cathode material and the sulfide solid electrolyte at a mass ratio of 1:1.

[0043] Sample loading: Accurately weigh 10.0 ± 0.5 mg of the mixture and place it in a crucible, cover it with the matching temperature-sensitive composite seal 2 to form an initial seal.

[0044] Testing: Place the crucible in a DSC, and under a flowing inert atmosphere (such as argon Ar, 50 mL / min), program the temperature from room temperature to 350 °C at a rate of 10 °C / min.

[0045] Data acquisition: The DSC records the heat flow signal in real time. Pay attention to the exothermic peak generated when the sample contacts the atmosphere after the temperature-sensitive composite seal 2 triggers the hole opening at the preset T point (usually accompanied by a small endothermic step).

[0046] 3. Quantitative evaluation and criteria Data processing: Integrate the exothermic peak after the hole opening, and calculate the integral heat release Q (mJ / mg) per unit mass of the sample. Q is the integral area of the curve obtained from the DSC test and the horizontal axis.

[0047] Risk level determination: Establish criteria based on the correlation of a large number of experimental and battery performance data: Q ≥ 270 mJ / mg: Determined as a "high-risk" combination, indicating poor cycle stability of the full battery and high thermal runaway risk.

[0048] 200 mJ / mg < Q < 270 mJ / mg: Determined as a "medium-risk" combination, which needs further verification.

[0049] Q ≤ 200 mJ / mg: Determined as a "low-risk" combination, with good interfacial compatibility.

[0050] Example 1: 185 °C low-temperature sensitive triggering The purpose of preparing the temperature-sensitive composite cap 2 involved in this embodiment is to achieve rapid, low-threshold triggering close to the lower limit of the temperature range.

[0051] Foaming agent: 1.8 wt% dicumyl peroxide (DCP) is used to achieve sensitive start-up by utilizing its concentration close to the decomposition point.

[0052] Matrix: Flexible polyimide with only 0.2 wt% divinylbenzene (DVB) added to maintain a loose network and reduce the binding of foaming agent molecules.

[0053] Coating: A 35 nm ultrathin Al2O3 coating is deposited, significantly reducing the pressure required for cracking. The low-temperature environment of S2 maximizes the suppression of pre-decomposition of the foaming agent.

[0054] The specific preparation process is as follows: The flexible polyimide was dissolved in a mixed solvent of N-methylpyrrolidone (NMP) and γ-butyrolactone (GBL) (mass ratio 7:3); Cool the mixture to -20°C, and slowly add 1.8 wt% DCP and 0.2 wt% DVB while continuously stirring (300 rpm) and with ultrasonic assistance (ultrasonic cell disruptor, power 400W, frequency 20kHz, pulse mode). After adding 2.0 wt% of surface-vinylened CeO2@SiO2 core-shell nanoparticles, the mixture was cyclically treated 5 times at 150 MPa using a high-pressure microfluidic homogenizer to ensure uniform nanoscale dispersion. Temperature treatment: Solvent evaporation section: 80℃ / 1 hour (for slow removal of most of the solvent) - 120℃ / 0.5 hours (for initial imidization of molecular chains) - 180℃ / 2 hours (for complete imidization). The cured PI film was ultrasonically cleaned with anhydrous ethanol for 5 minutes, then dried in a vacuum oven at 80°C for 2 hours, and then placed in the vacuum chamber of a magnetron sputtering instrument. Using high-purity aluminum as the target material, reactive sputtering was performed in an argon / oxygen mixed atmosphere at a power of 90 W to deposit a dense Al2O3 coating with a thickness of 50±10 nm and moderate internal stress on the film surface. Finally, the composite membrane is cut to a predetermined size to obtain the temperature-sensitive composite cap 2.

[0055] Key process: The final curing temperature is strictly controlled at 180℃.

[0056] The porous substrate and ultra-thin coating enable the system to respond rapidly when the blowing agent (DCP) begins to decompose, triggering the temperature to shift towards the theoretical lower limit.

[0057] Example 2: 200℃ Basic Standard Trigger The purpose of preparing the temperature-sensitive composite cap 2 involved in this embodiment is to establish the most classic and balanced technical solution benchmark.

[0058] Foaming agent: 1.7 wt% DCP, which is the standard content.

[0059] Matrix: Standard polyimide, 0.4 wt% DVB, forming a moderately cross-linked network.

[0060] Coating: 50 nm standard thickness Al2O3 coating.

[0061] The specific preparation process is as follows: The standard polyimide was dissolved in a mixed solvent of N-methylpyrrolidone (NMP) and γ-butyrolactone (GBL) (mass ratio 7:3); Cool the mixture to -20°C, and slowly add 1.7 wt% DCP and 0.4 wt% DVB while continuously stirring (300 rpm) and with ultrasonic assistance (ultrasonic cell disruptor, power 400W, frequency 20kHz, pulse mode). After adding 2.0 wt% of surface-vinylened CeO2@SiO2 core-shell nanoparticles, the mixture was cyclically treated 5 times at 150 MPa using a high-pressure microfluidic homogenizer to ensure uniform nanoscale dispersion. Temperature treatment: Solvent evaporation section: 80℃ / 1 hour (for slow removal of most of the solvent) - 120℃ / 0.5 hours (for initial imidization of molecular chains) - 185℃ / 2 hours (for complete imidization). The cured PI film was ultrasonically cleaned with anhydrous ethanol for 5 minutes, then dried in a vacuum oven at 80°C for 2 hours, and then placed in the vacuum chamber of a magnetron sputtering instrument. Using high-purity aluminum as the target material, reactive sputtering was performed in an argon / oxygen mixed atmosphere at a power of 90 W to deposit a 50 nm thick, dense Al2O3 coating with moderate internal stress on the film surface. Finally, the composite membrane is cut to a predetermined size to obtain the temperature-sensitive composite cap 2.

[0062] Key process: Final curing temperature 185℃.

[0063] 3. Expected results and mechanism: The balanced matching of all parameters ensures that the trigger temperature accurately corresponds to the 1-minute half-life temperature of the DCP, demonstrating the reliability of the basic scheme.

[0064] Example 3: Triggering of medium-temperature compounding at 250℃ The purpose of preparing the temperature-sensitive composite cap 2 involved in this embodiment is to cross the temperature range of a single foaming agent through compounding technology.

[0065] Foaming agent: 4,4'-oxobis(benzenesulfonyl hydrazine) (OBSH) (1.5 wt%) and DCP (0.3 wt%) are compounded. DCP decomposes first as an "ignition agent", and its heat generation and active environment promote the subsequent decomposition of OBSH at a slightly lower temperature.

[0066] Matrix: Biphenyl-type rigid PI was selected, and DVB was increased to 1.0 wt% to improve network rigidity.

[0067] Coating: Thickened to 100 nm.

[0068] The specific preparation process is as follows: Biphenyl polyimide (BPDA-PI) was dissolved in a mixed solvent of N-methylpyrrolidone (NMP) and γ-butyrolactone (GBL) (mass ratio 7:3); Cool the mixture to -20°C, and slowly add 1.5 wt% OBSH, 0.3 wt% DCP and 1.0 wt% DVB while continuously stirring (300 rpm) and with ultrasonic assistance (ultrasonic cell disruptor, power 400W, frequency 20kHz, pulse mode). After adding 2.0 wt% of surface-vinylened CeO2@SiO2 core-shell nanoparticles, the mixture was cyclically treated 5 times at 150 MPa using a high-pressure microfluidic homogenizer to ensure uniform nanoscale dispersion. Temperature treatment: Solvent evaporation section: 80℃ / 1 hour (for slow removal of most of the solvent) - 120℃ / 0.5 hours (for initial imidization of molecular chains) - 190℃ / 2 hours (for complete imidization). The cured PI film was ultrasonically cleaned with anhydrous ethanol for 5 minutes, then dried in a vacuum oven at 80°C for 2 hours, and then placed in the vacuum chamber of a magnetron sputtering instrument. Using high-purity aluminum as the target material, reactive sputtering was performed in an argon / oxygen mixed atmosphere at a power of 90 W to deposit a 100 nm thick, dense Al2O3 coating with moderate internal stress on the film surface. Finally, the composite membrane is cut to a predetermined size to obtain the temperature-sensitive composite cap 2.

[0069] Key process: Curing temperature 190℃ (still below the point where DCP decomposes significantly).

[0070] The synergistic effect of the compound, together with the enhanced matrix and coating, stabilizes the trigger point to the main decomposition range of OBSH.

[0071] Example 4: High-temperature catalytic triggering at 280℃ The purpose of preparing the temperature-sensitive composite cap 2 involved in this embodiment is to use a catalyst to challenge higher trigger temperatures.

[0072] Foaming agent: High-temperature foaming agent trihydrazine triazine (THT) (1.8 wt%) is used, and 0.5 wt% of nano iron oxide is added as a decomposition catalyst to reduce its apparent decomposition activation energy.

[0073] Matrix: Highly cross-linked rigid PI (DVB 1.5 wt%).

[0074] Coating: 130 nm ultra-thick coating.

[0075] The specific preparation process is as follows: High-rigidity polyimide was dissolved in a mixed solvent of N-methylpyrrolidone (NMP) and γ-butyrolactone (GBL) (mass ratio 7:3); Cool the mixture to -20°C, and slowly add 1.8 wt% THT, 0.5 wt% nano Fe2O3 and 1.5 wt% DVB while continuously stirring (300 rpm) and with ultrasonic assistance (ultrasonic cell disruptor, power 400W, frequency 20kHz, pulse mode). After adding 2.0 wt% of surface-vinylened CeO2@SiO2 core-shell nanoparticles, the mixture was cyclically treated 5 times at 150 MPa using a high-pressure microfluidic homogenizer to ensure uniform nanoscale dispersion. Temperature treatment: Solvent evaporation section: 80℃ / 1 hour (for slow removal of most of the solvent) - 120℃ / 0.5 hours (for initial imidization of molecular chains) - 200℃ / 2 hours (for complete imidization). The cured PI film was ultrasonically cleaned with anhydrous ethanol for 5 minutes, then dried in a vacuum oven at 80°C for 2 hours, and then placed in the vacuum chamber of a magnetron sputtering instrument. Using high-purity aluminum as the target material, reactive sputtering was performed in an argon / oxygen mixed atmosphere at a power of 90 W to deposit a dense Al2O3 coating with a thickness of 130 nm and moderate internal stress on the film surface. Finally, the composite membrane is cut to a predetermined size to obtain the temperature-sensitive composite cap 2.

[0076] Key process: The curing temperature can be slightly increased to 200℃ (THT is stable at this temperature).

[0077] The catalyst solves the problem of insufficient decomposition kinetics of high-temperature foaming agents, and together with a high-strength substrate and coating, it achieves reliable triggering at high temperatures.

[0078] Example 5: 300℃ Limiting Polymer Replacement Trigger The purpose of preparing the temperature-sensitive composite cap 2 involved in this embodiment is to explore the upper limit of the temperature range and prove the platformization capability by replacing the matrix material.

[0079] Foaming agent: THT (2.0 wt%) with a higher content of catalyst (0.8 wt%).

[0080] Matrix: The polymer is replaced with polyethersulfone (PES). PES itself has excellent high-temperature dimensional stability, and its molding temperature (e.g., 220°C) is compatible with the active protection temperature of THT.

[0081] Coating: 150 nm maximum thickness.

[0082] The specific preparation process is as follows: Polyethersulfone (PES) resin was dissolved in N-methylpyrrolidone (NMP); Under continuous stirring (300 rpm) and ultrasonic assistance (ultrasonic cell disruptor, power 400W, frequency 20kHz, pulse mode), 2.0 wt% THT and 0.8 wt% nano Fe2O3 were slowly added to the mixture. After adding 2.0 wt% of surface-vinylened CeO2@SiO2 core-shell nanoparticles, the mixture was cyclically treated 5 times at 150 MPa using a high-pressure microfluidic homogenizer to ensure uniform nanoscale dispersion. Temperature treatment: The formed film is treated at 220℃ for 2 hours to allow the PES resin to fully cure. The cured PES film was ultrasonically cleaned with anhydrous ethanol for 5 minutes, then dried in a vacuum oven at 80°C for 2 hours, and then placed in the vacuum chamber of a magnetron sputtering instrument. Using high-purity aluminum as the target material, reactive sputtering was performed in an argon / oxygen mixed atmosphere at a power of 90 W to deposit a dense Al2O3 coating with a thickness of 150 nm and moderate internal stress on the film surface. Finally, the composite membrane is cut to a predetermined size to obtain the temperature-sensitive composite cap 2.

[0083] Key process: Uses a molding and curing temperature of 220℃ corresponding to PES.

[0084] The successful replacement of the polymer matrix proves that the technical concept of this invention is not limited to PI, but is a platform solution that can be adapted to multiple systems, greatly expanding the scope of protection.

[0085] It should be noted that the specific embodiments described above are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention. These solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A method for preparing an intelligent temperature-controlled atmosphere switching crucible for thermal analysis, characterized in that, Includes the following steps: S1 polyimide precursor or PES resin is dissolved in a mixed solvent of N-methylpyrrolidone and γ-butyrolactone in a mass ratio of 7:3; S2. Cool the mixture to -20°C, and add the foaming agent and crosslinking agent under continuous stirring and ultrasonic assistance; After adding 1.0 wt% to 4.0 wt% of surface-modified nanoparticles to S3, the slurry was homogenized and cyclically treated 5 times at 150 MPa to prepare a wet film with a thickness of 200±20 μm. S4 is treated at 75-85℃ for 1-1.5 hours to evaporate the solvent, then treated at 115-125℃ for 0.4-0.6 hours to induce initial cyclization of the molecular chains, and finally treated at 180-300℃ for 2 hours to completely imidize the material. The S5 cured PI film is sprayed with an inorganic barrier coating (23); The S6 composite membrane is cut to match the size of the crucible body (1) to obtain a temperature-sensitive composite cap (2) that is detachably sealed to the opening of the crucible body (1).

2. The method for preparing the intelligent temperature-controlled atmosphere switching crucible for thermal analysis according to claim 1, characterized in that, In S4, the processing temperature for fully imidizing the material is 180°C, 185°C, 190°C, 200°C, or 300°C.

3. The method for preparing the intelligent temperature-controlled atmosphere switching crucible for thermal analysis according to claim 1, characterized in that, The polyimide precursor is polyimide, biphenyl-type BPDA-PI, or polyethersulfone.

4. The method for preparing the intelligent temperature-controlled atmosphere switching crucible for thermal analysis according to claim 1, characterized in that, The inorganic barrier coating (23) has a thickness of 35-150 nm.

5. The method for preparing the intelligent temperature-controlled atmosphere switching crucible for thermal analysis according to claim 1, characterized in that, The inorganic barrier coating (23) is an Al2O3 or SiO2 thin film.

6. The method for preparing the intelligent temperature-controlled atmosphere switching crucible for thermal analysis according to claim 1, characterized in that, The spraying method is magnetron sputtering deposition.

7. A smart temperature-controlled atmosphere switching crucible for thermal analysis, obtained based on the preparation method described in claims 1-6, characterized in that, It includes a crucible body (1) and a temperature-sensitive composite cap (2) that matches the crucible body (1) and is detachably sealed over the opening of the crucible body (1).

8. The application of the intelligent temperature-controlled atmosphere switching crucible for thermal analysis obtained by the preparation method according to claims 1-6 in the simulation experiment of thermal analysis technology.

9. The application according to claim 8, characterized in that, The thermal analysis simulation experiment is a thermal decomposition simulation experiment of a ternary cathode battery.

10. A method for thermal risk assessment, characterized in that, Includes the following steps: Analyze the thermal decomposition initiation temperature of the material to be tested, and select or customize a crucible cap that matches the trigger temperature T. Prepare the experimental materials, place them in the crucible, and cover them with a temperature-sensitive composite cap (2) to form an initial seal; Collect the heat flow signal triggered by the temperature-sensitive composite cap (2) to open the hole, and calculate the integral heat release Q per unit mass of sample.

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