High-temperature-resistant multi-mode flexible sensing array based on rotating negative Poisson's ratio structure interposer, and preparation method and application of high-temperature-resistant multi-mode flexible sensing array

Abstract

The invention relates to a high-temperature-resistant multi-mode flexible sensing array based on a rotary negative Poisson's ratio structure interposer and a preparation method and application thereof, and the sensing array comprises a top packaging layer, a temperature sensing layer, a negative Poisson's ratio structure interposer, a piezoelectric sensing layer and a substrate packaging layer which are sequentially stacked from top to bottom. The negative Poisson's ratio structure intermediate layer is made of a high-modulus flexible composite material and comprises a plurality of rigid rotating units and flexible connecting areas, and a rotating square negative Poisson's ratio microstructure is formed. A thermal resistance type temperature sensing unit of the temperature sensing layer is arranged on the upper surface of the rigid rotating unit and comprises a graphene conductive network. The piezoelectric sensing layer comprises a three-dimensional interconnected leadless piezoelectric ceramic skeleton and an array stretchable electrode, is packaged in a flexible polymer matrix, and is used for sensing mechanical deformation. Compared with the prior art, the multi-mode flexible sensing array has the decoupling capability, and a flexible multi-mode sensor which can independently output temperature and mechanical deformation signals can be realized.

Description

Technical Field

[0001] The present invention relates to a multimodal flexible sensing array, in particular to a high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure intermediary layer, and a preparation method and application thereof. Background Art

[0002] With the rapid development of the Internet of Things (IoT), the demand for flexible sensors that can operate stably in complex environments is increasing. In recent years, researchers have developed a variety of flexible sensors based on the detection of various external stimuli such as mechanics, thermal and chemical, and they have been widely used in fields such as health monitoring, soft robotics, electronic skin and structural diagnosis. However, most sensors are still limited to a single signal mode. The main reason is that there is mutual interference between different sensing mechanisms, which makes it difficult to achieve effective fusion, seriously restricting the development of their multifunctional integration. In highly coupled systems such as lithium-ion batteries, temperature and mechanical strain are often intertwined and superimposed. Processes such as heat accumulation, gas release, and electrode expansion are unevenly distributed in space and affect each other. Therefore, accurate diagnosis of their operating status urgently requires a high-performance sensing platform with the ability to decouple strain and temperature signals.

[0003] However, most existing multimodal sensing solutions are only applicable to low-temperature environments such as electronic skin, and still face problems such as functional degradation and signal interference in high-temperature fields. It is crucial to develop highly sensitive and stable multimodal flexible sensors that can operate in environments above 100°C. In order to achieve reliable separation of multimodal signals, researchers have proposed a variety of decoupling strategies that rely on algorithm identification in recent years, such as using external circuits and neural network models to analyze the coupled signals of sensors. However, such methods usually rely on high-performance computing modules, and the system is complex, energy-intensive, and difficult to meet the equipment's requirements for miniaturization and real-time response. In contrast, the physical-level decoupling strategy based on the device structure itself has become an important development direction for multimodal fusion due to its compactness and high efficiency.

[0004] Common structural decoupling methods currently include leveraging the varying sensitivity of materials to temperature and strain for identification, or physically separating different sensing units in parallel or stacked within the device. The former, due to non-ideal coupling at the composite interface, makes it difficult to achieve completely orthogonal responses. While the latter avoids complex signal processing, mutual interference between sensing parameters can still affect the final decoupling accuracy.

[0005] CN114076564A proposes a strain sensor array based on a negative Poisson's ratio structure. While this sensor exhibits high sensitivity and high stretchability, it is limited to strain detection and cannot simultaneously sense temperature and mechanical deformation. Furthermore, the sensor's stability in high-temperature environments has not been fully verified, making it difficult to meet the demands of demanding applications such as lithium battery thermal runaway monitoring.

[0006] CN110426063A reports a dual-mode sensor combining piezoelectric layer and piezoresistive layer to realize pressure and strain detection. However, the design does not involve temperature sensing function, and the signals of the piezoelectric layer and the piezoresistive layer are easily interfered with each other, resulting in great difficulty in decoupling. When facing systems with high coupling of temperature and mechanical deformation (such as lithium ion batteries), the monitoring accuracy is limited.

[0007] Therefore, it is urgent to develop a flexible multi-modal sensor with decoupling capability and capable of realizing independent output of temperature and mechanical deformation signals. SUMMARY

[0008] The purpose of the present application is to overcome the defects of the prior art and provide a high-temperature-resistant multi-modal flexible sensing array based on a rotating negative Poisson's ratio structure interlayer and a preparation method and application thereof. A flexible multi-modal sensor with decoupling capability and capable of realizing independent output of temperature and mechanical deformation signals is mainly developed.

[0009] The purpose of the present application can be realized by the following technical solutions:

[0010] The present application provides a high-temperature-resistant multi-modal flexible sensing array based on a rotating negative Poisson's ratio structure interlayer, which comprises a top packaging layer, a temperature sensing layer, a negative Poisson's ratio structure interlayer, a piezoelectric sensing layer and a substrate packaging layer stacked from top to bottom.

[0011] The negative Poisson's ratio structure interlayer is composed of a high-modulus flexible composite material, and the negative Poisson's ratio structure interlayer has a rotating square negative Poisson's ratio microstructure comprising a plurality of rigid rotating units and a flexible connecting area.

[0012] The temperature sensing layer comprises a thermal resistance type temperature sensing unit arranged on the upper surface of the rigid rotating unit by means of dispensing, and the thermal resistance type temperature sensing unit is used for sensing the change of ambient temperature. The thermal resistance type temperature sensing unit comprises a graphene conductive network.

[0013] The piezoelectric sensing layer comprises a three-dimensional interconnected lead-free piezoelectric ceramic skeleton encapsulated in a flexible polymer matrix and an arrayed stretchable electrode attached to the surface of the three-dimensional interconnected lead-free piezoelectric ceramic skeleton, thereby forming an arrayed piezoelectric sensing unit. The piezoelectric sensing layer is used for sensing mechanical deformation.

[0014] The substrate packaging layer is composed of a thick layer of flexible polymer, and the thickness of the substrate packaging layer is configured so that the temperature sensing layer and the piezoelectric sensing layer are away from the neutral axis of the sensing array.

[0015] The working temperature range of the multi-modal flexible sensing array is 25℃ to 130℃.

[0016] Furthermore, the material of the three-dimensional interconnected lead-free piezoelectric ceramic skeleton is potassium sodium niobate, the microstructure is a three-dimensional porous network, and the crystal phase is a perovskite orthorhombic phase. The three-dimensional interconnected lead-free piezoelectric ceramic skeleton is prepared on a polymer foam template by a template-assisted sol-gel method and formed by sintering.

[0017] Furthermore, the rigid rotation unit in the rotating square negative Poisson's ratio microstructure has a size of 1.5 mm × 1.5 mm, a rotation angle of 30°–45°, and a width of the flexible connection area of ​​0.2–0.5 mm;

[0018] The top corners of the rigid rotating unit are completely covered by the flexible connection area, forming a topologically continuous non-orthogonal hinged structure;

[0019] The center point of the rigid rotating unit coincides with the center point of the piezoelectric sensing unit.

[0020] Furthermore, the arrayed stretchable electrodes are coated on the surface of the three-dimensional interconnected lead-free piezoelectric ceramic skeleton through a template printing process, and the electrode material is a stretchable conductive silver paste.

[0021] Furthermore, the flexible polymer matrices of the top packaging layer, the base packaging layer, and the piezoelectric sensing layer are all made of polydimethylsiloxane.

[0022] A second aspect of the present invention provides a method for preparing a high-temperature resistant multimodal flexible sensing array based on a rotated negative Poisson's ratio structure interposer as described above, comprising the following steps:

[0023] S1: Preparation of piezoelectric sensing layer

[0024] A three-dimensional interconnected lead-free piezoelectric ceramic skeleton is prepared by a template-assisted sol-gel method, specifically comprising: dissolving an alkali metal acetate and niobium ethoxide in an organic solvent at a predetermined ratio, adding a sintering compensator, stirring and aging the mixture to form a precursor sol, uniformly coating the precursor sol on the surface of a porous polymer template, and sintering the mixture to form a three-dimensional interconnected lead-free piezoelectric ceramic skeleton;

[0025] Cutting the three-dimensional interconnected lead-free piezoelectric ceramic skeleton, polarizing it, and casting a flexible polymer package, and then printing a stretchable electrode array on the surface;

[0026] S2: Integration of temperature sensing layer and negative Poisson's ratio structure intermediary layer

[0027] Laser processing of rotating square negative Poisson's ratio microstructures on high modulus composite films enables the flexible connection area to completely cover the top corners of the rigid units to form non-orthogonal hinges;

[0028] A conductive paste with a negative temperature coefficient response is applied to the upper surface of the rigid unit and solidified to form a thermal resistance temperature sensing unit;

[0029] S3: Full device assembly

[0030] spin coating the adhesive onto a thick layer of flexible polymer substrate;

[0031] The piezoelectric sensing layer, the negative Poisson's ratio intermediary layer, and the temperature sensing layer are stacked in sequence, and the positioning and matching are performed so that the temperature sensing unit corresponds to the piezoelectric sensing unit in space;

[0032] The flexible polymer encapsulation layer is covered and cured to obtain a high-temperature resistant multimodal flexible sensing array.

[0033] Furthermore, in S1, the specific steps of preparing the piezoelectric sensing layer include: dissolving potassium acetate and sodium acetate in a molar ratio of 0.48:0.52 in ethylene glycol methyl ether, adding 3-10 mol% of acetate to compensate for sintering loss, dissolving niobium ethoxide in 2-methoxyethanol, and adding acetylacetone to regulate the hydrolysis rate, then combining the two solutions and stirring for 6 hours, and aging at room temperature for 24 hours to obtain a precursor sol with a concentration of 0.5M;

[0034] A polyurethane foam template with a thickness of 3 mm and a pore density of 40 ppi was fixed on the base of an ultrasonic spraying machine, and the precursor sol was sprayed using ultrasonic spraying technology. The spraying parameters were: frequency 80 kHz, air pressure 0.5 MPa, nozzle speed 20-50 mm / s, liquid flow rate 6-15 μL / s, spray width 8 mm, and 15 sprayings on both sides.

[0035] Anneal the sprayed template at 1000°C for 40-90 minutes to form a three-dimensional interconnected lead-free piezoelectric ceramic skeleton;

[0036] The three-dimensional interconnected lead-free piezoelectric ceramic skeleton was cut into 6 cm × 6 cm size and subjected to corona poling treatment for 40 min;

[0037] Subsequently, PDMS packaging is cast to form a piezoelectric sensing layer. After the PDMS is solidified, plasma treatment is performed on its surface, and a stretchable silver paste is printed using a template to form an arrayed electrode pattern.

[0038] Furthermore, in S2, the specific steps of integrating the temperature sensing layer with the negative Poisson's ratio structure intermediary layer include:

[0039] PEDOT:PSS, sodium carboxymethyl cellulose, graphene and deionized water were mixed in a mass ratio of 9:3:1:60 to prepare a conductive suspension. The suspension was ultrasonically treated for 12-24 hours and stirred for 24 hours to ensure uniform dispersion.

[0040] A 500 μm thick glass fiber-PDMS composite membrane was processed into a rotating square negative Poisson's ratio structure using a CO2 laser platform and then plasma treated.

[0041] 3-8 μL of conductive suspension is dropped onto the rigid area of ​​the rotating grid negative Poisson's ratio structure using a dispensing method and cured at 80°C-140°C to form a temperature sensing unit;

[0042] The temperature sensing unit is connected to the external circuit by wire bonding to ensure stable signal transmission. The PDMS layer is then encapsulated on the temperature sensor to obtain a composite structure integrating the temperature sensing layer and the negative Poisson's ratio structure intermediary layer.

[0043] Furthermore, in S3, the process of full device assembly includes:

[0044] spin coating the adhesive onto a thick layer of flexible polymer substrate;

[0045] The piezoelectric sensing layer, the negative Poisson's ratio structure intermediary layer, and the temperature sensing layer are stacked in sequence, and the thermal resistance temperature sensing units of the temperature sensing layer and the piezoelectric sensing units of the piezoelectric sensing layer are spatially aligned through positioning matching;

[0046] Cover the top encapsulation layer and apply uniform pressure to make each functional layer tightly bonded;

[0047] The material is cured to form a high-temperature resistant multimodal flexible sensing array.

[0048] A third aspect of the present invention provides an application of the high-temperature-resistant multimodal flexible sensing array based on the above-mentioned rotated negative Poisson's ratio structure interposer. The multimodal flexible sensing array is attached to the surface of a lithium-ion battery to simultaneously detect the surface temperature and mechanical deformation of the battery to identify abnormal conditions such as overheating and swelling of the battery. The specific method includes:

[0049] A multimodal flexible sensing array is attached to the surface of the battery outer packaging;

[0050] The heat accumulation process inside the battery is simulated by heating, and gas is injected into the battery to simulate the swelling phenomenon;

[0051] Monitor the resistance change of the temperature sensing unit and the voltage output of the piezoelectric sensing unit;

[0052] Based on the characteristic curves of temperature and voltage changes, determine whether the battery is in an abnormal state of overheating or swelling.

[0053] This paper conceives a novel multimodal sensing decoupling strategy. By utilizing a high-modulus rotating lattice negative Poisson's ratio structure, it achieves physical independence and functional decoupling of the two sensing mechanisms, temperature and mechanical deformation. This strategy is suitable for real-time monitoring of complex thermo-mechanical coupling states in high-temperature environments exceeding 100°C. Specifically, a negative Poisson's ratio structure with rotating units was constructed within a glass fiber-reinforced PDMS composite film (GFF-PDMS) using laser cutting technology. A lead-free KNN–PDMS piezoelectric sensing layer, prepared via a template-assisted sol-gel method, was integrated onto its lower surface. Simultaneously, a thermal resistive temperature sensing unit based on a small polaron hopping mechanism was assembled onto the rigid region of the structure's upper surface via dispensing. During stretching, this composite structure exhibits the geometric characteristics of rigid unit rotation and flexible connection region expansion. This effectively shields the temperature sensor from mechanical strain interference and transforms the uniaxial stretching of the piezoelectric layer into enhanced in-plane multidirectional deformation, significantly improving the piezoelectric element's sensitivity in the d31 mode. Through functional partitioning and physical decoupling at the structural level, independent perception of temperature and deformation signals in the same device is achieved. Experimental results show that the temperature sensing unit exhibits a stable negative temperature coefficient (NTC) response in the range of 25–130°C, with a maximum resistance change rate of up to –65%, and is not affected by tensile deformation; the piezoelectric sensor can sensitively detect subtle surface protrusion changes as small as 5μm, without being affected by temperature. After the sensor array is installed on the surface of a soft-pack lithium battery, it can effectively identify early failure modes such as overheating and swelling, verifying the good applicability and development potential of the invention in engineering applications such as structural health monitoring in high-temperature environments.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) A new temperature-strain decoupling strategy is proposed. By introducing a high modulus negative Poisson's ratio structure, piezoelectric and thermal resistance sensors can work independently on the same platform without interfering with each other. At the same time, this structural design also provides a deformation gain effect, which effectively improves the piezoelectric response sensitivity.

[0056] (2) A flexible 3-3 composite piezoelectric material based on lead-free KNN was successfully prepared, and its intrinsic performance deficiencies were compensated through structural design, achieving real-time detection of surface protrusions as small as 5μm.

[0057] (3) The device has good high-temperature stability. The temperature sensor maintains a stable NTC response in the range of 25–130°C (maximum resistance change –65%). It is suitable for multimodal information acquisition in high-temperature environments, especially in engineering safety monitoring scenarios such as lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1This is a flow chart of the preparation of the multimodal sensor array in the embodiment

[0059] Figure 2 The morphology comparison between the KNN piezoelectric skeleton and the template in the embodiment

[0060] Figure 3 This is a transmission electron microscope image of the KNN piezoelectric skeleton in the embodiment

[0061] Figure 4 The X-ray diffraction pattern and piezoelectric force microscopy characterization of the KNN skeleton prepared in the embodiment

[0062] Figure 5 The voltage output of the piezoelectric sensor prepared in the embodiment under 5-20 μm protrusion deformation

[0063] Figure 6 The temperature change curve of the temperature sensor prepared in the embodiment

[0064] Figure 7 The output of the piezoelectric sensor prepared in the embodiment is affected by temperature

[0065] Figure 8 The temperature sensor prepared in the embodiment is affected by pressure and bending deformation

[0066] Figure 9 This is the phase transition temperature test diagram of the KNN skeleton prepared in the embodiment

[0067] Figure 10 The strain characteristics of the multimodal sensor in the embodiment are studied by comosol

[0068] Figure 11 It is the output of the multimodal sensor array to monitor battery overheating and expansion DETAILED DESCRIPTION

[0069] Overall, this invention provides the design and fabrication of a multimodal flexible sensor array capable of sensing both temperature and mechanical deformation. This invention proposes a novel decoupled sensing strategy: a high-modulus, rotated square negative Poisson's ratio (NPR) structure film is laminated and integrated with a low-modulus, 3-3 composite, lead-free piezoelectric composite film based on a continuous KNN framework. The temperature sensing element (PG sensor) is attached to the rigid regions of the NPR structure. During bending, these rigid regions rotate solely, effectively isolating the effects of tensile strain on its resistance. Furthermore, the NPR geometry converts uniaxial deformation in the piezoelectric layer into multidirectional in-plane deformation, significantly improving the piezoelectric output performance in the d31 mode. The fabricated piezoelectric layer exhibits 100% stretchability and can independently detect surface deformations as small as 5μm at temperatures up to 130°C. The temperature sensor exhibits a stable negative temperature coefficient (NTC) response (based on a small polaron hopping conduction mechanism) over the temperature range of 25 to 130°C, with a maximum resistance change of up to –65%, while remaining insensitive to pressure and bending. When the sensor array is applied to the surface of soft-pack batteries, it successfully identifies abnormal conditions such as battery overheating and bulging, demonstrating its great potential for structural health monitoring in harsh engineering environments.

[0070] In view of this, the present invention aims to propose a new strategy to achieve decoupling of temperature and mechanical deformation signals. By using a high-modulus negative Poisson's ratio structure as an intermediary, the piezoelectric strain sensor and the thermal resistance temperature sensor can operate independently on the same platform, avoiding signal interference between different sensing mechanisms. This negative Poisson's ratio structure not only achieves physical decoupling, but also enhances the deformation response of the piezoelectric layer in the in-plane direction through the geometric amplification effect, thereby enhancing its output signal strength. In the present invention, a 3-3 type composite piezoelectric sensor based on lead-free KNN is prepared, which has excellent flexibility and up to 100% stretchability. The multimodal sensor can also operate at temperatures exceeding 100°C. When the multimodal sensing array is applied to the surface of soft-pack batteries, typical safety failure events such as overheating and swelling can be successfully identified, demonstrating excellent practicality and environmental adaptability. The present invention provides a new paradigm for the design of multimodal sensors to achieve dual-parameter physical decoupling, and has broad engineering application potential.

[0071] In a specific implementation, an anisotropic high-sensitivity flexible piezoelectric sensor includes the following steps:

[0072] (1) Preparation of KNN ceramic piezoelectric sensing layer:

[0073] The KNN skeleton structure was prepared by a template-assisted sol-gel method, which specifically includes:

[0074] Potassium acetate and sodium acetate were dissolved in ethylene glycol methyl ether with a molar ratio of 0.48:0.52, 3-10 mol% of acetate was added to compensate for sintering loss, niobium ethoxide was dissolved in 2-methoxyethanol in a glove box, and acetylacetone was added to control the hydrolysis rate, the two solutions were combined and stirred for 6 hours, and aged at room temperature for 24 hours to obtain a precursor sol with a concentration of 0.5M. A polyurethane foam template with a thickness of 3mm and a pore density of 40ppi was fixed on the substrate of an ultrasonic spraying machine, the KNN sol was sprayed by ultrasonic spraying technology, the spraying parameters were: frequency 80kHz, air pressure 0.5MPa, nozzle speed 20-50mm / s, liquid flow rate 6-15μL / s, spraying width 8mm, and each side was sprayed 15 times. The sprayed template was annealed at 1000°C to form a KNN ceramic skeleton.

[0075] (2) Piezoelectric layer polarization and electrode construction:

[0076] The KNN ceramic skeleton was cut into a size of 6cm×6cm and subjected to corona polarization treatment for 40min; then PDMS encapsulation was poured to form a piezoelectric sensing layer, after the PDMS was cured, the surface was subjected to plasma treatment, and a stretchable silver paste was used to form an arrayed electrode pattern using a template.

[0077] (3) Preparation of temperature sensing layer:

[0078] PEDOT:PSS, sodium carboxymethyl cellulose (CMC), graphene and deionized water were mixed in a mass ratio of 9:3:1:60 to prepare a conductive suspension, the suspension was ultrasonically treated for 12-24 hours and continuously stirred for 24 hours to ensure uniform dispersion, a 500μm thick glass fiber (GFF)-PDMS composite film was processed into a negative Poisson's ratio structure by a CO2 laser platform and subjected to plasma treatment, 3-8μL of conductive suspension was added to the stable rigid area in the structure by dispensing, and solidification was carried out at 80°C-140°C to form a temperature sensing unit. After electrical connection, a PDMS layer was encapsulated on the temperature sensor to protect the sensor from external environmental interference.

[0079] (4) Integration and assembly of multi-modal device:

[0080] A 4mm thick PDMS substrate was used as the bottom layer, a 3mm thick piezoelectric layer and a 500μm thick temperature sensing layer were bonded, spin-coated PDMS was used as an adhesive, the piezoelectric unit and the temperature unit maintained a 2×2 array unit one-to-one correspondence, and the PDMS substrate layer was used to make the sensing unit away from the neutral axis distribution, so as to enhance the mechanical response sensitivity and realize signal decoupling.

[0081] In specific implementation, the preparation method of the KNN sol in step 1) and the large-area preparation method assisted by the ultrasonic spraying machine include the following specific steps:

[0082] 1) Potassium acetate and sodium acetate are dissolved in ethylene glycol methyl ether at a molar ratio of 0.48:0.52, and 3-10 mol% of acetate is added to compensate for sintering losses;

[0083] 2) Dissolve niobium ethoxide in ethylene glycol methyl ether in a glove box, and add acetylacetone to control the hydrolysis rate;

[0084] 3) The two solutions were combined and stirred for 6 hours, and aged at room temperature for 24 hours to obtain a precursor sol with a concentration of 0.5 M;

[0085] 3) A polyurethane foam template with a thickness of 3 mm and a pore density of 40 ppi was fixed on the base of an ultrasonic sprayer, and the KNN sol was sprayed using ultrasonic spraying technology. The spraying parameters were: frequency 80 kHz, air pressure 0.5 MPa, nozzle speed 20-50 mm / s, liquid flow rate 6-15 μL / s, spray width 8 mm, and 15 sprayings on both sides.

[0086] In specific implementation, the KNN skeleton annealing temperature in step 1) is 1000° C., and the annealing time is 40-90 min.

[0087] In a specific implementation, the electrode pattern in step 1) is coated on the surface of the KNN skeleton by template printing, and the silver paste used is a stretchable conductive silver paste.

[0088] In a specific implementation, the negative Poisson's ratio structure of the temperature sensing layer in step 2) is a rotating grid structure.

[0089] In specific implementation, the steps of preparing the temperature sensing layer in step 2) include:

[0090] The conductive suspension contains PEDOT:PSS, sodium carboxymethyl cellulose (CMC), graphene and deionized water in a mass ratio of 9:3:1:60, which are uniformly mixed by ultrasonication and stirring.

[0091] The conductive suspension is coated on the negative Poisson's ratio template by dispensing.

[0092] The drying temperature of the conductive suspension is 80°C-140°C.

[0093] In a specific implementation, the piezoelectric sensing layer and the temperature sensing layer in step 4) are fully covered and bonded by spin coating with PDMS, with a spin coating speed of 700 rpm and a spin coating time of 30 seconds.

[0094] In specific implementation, the overall packaging material of the device in steps 1) to 4) is Sylgard 184 type PDMS, and the mass ratio of the base component to the curing agent is 10:1.

[0095] In a specific implementation, a high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer includes a top packaging layer, a temperature sensing layer, a negative Poisson's ratio structure interposer, a piezoelectric sensing layer, and a base packaging layer stacked in sequence from top to bottom, wherein:

[0096] The negative Poisson's ratio structural intermediary layer is composed of a high modulus flexible composite material, and the negative Poisson's ratio structural intermediary layer has a rotating grid negative Poisson's ratio microstructure comprising multiple rigid rotating units and flexible connection areas; the temperature sensing layer includes a thermal resistance temperature sensing unit arranged on the upper surface of the rigid rotating unit by dispensing, and the thermal resistance temperature sensing unit is used to sense changes in ambient temperature, and the thermal resistance temperature sensing unit includes a graphene conductive network; the piezoelectric sensing layer includes a three-dimensional interconnected lead-free piezoelectric ceramic skeleton encapsulated in a flexible polymer matrix and an arrayed stretchable electrode attached to the surface of the three-dimensional interconnected lead-free piezoelectric ceramic skeleton, thereby forming an arrayed piezoelectric sensing unit, and the piezoelectric sensing layer is used to sense mechanical deformation; the base packaging layer is composed of a thick layer of flexible polymer, and the thickness of the base packaging layer is configured to make the temperature sensing layer and the piezoelectric sensing layer away from the neutral axis of the sensing array; the operating temperature range of the multimodal flexible sensing array is 25°C to 130°C. The stability in this temperature range is due to the selection of materials and structural design of each layer, especially the high modulus flexible composite materials of the negative Poisson's ratio structural interposer and the base packaging layer, which can still maintain good mechanical and electrical properties at high temperatures.

[0097] In specific implementations, the negative Poisson's ratio interposer is constructed from a high-modulus flexible composite material featuring a rotating grid of negative Poisson's ratio microstructures consisting of multiple rigid rotating units and flexible connection regions. When subjected to tension, the rigid rotating units primarily rotate, while the flexible connection regions bear the tensile strain. The temperature sensing layer utilizes a dispensing method to apply thermal resistance temperature sensing elements to the upper surface of the rigid rotating units within the negative Poisson's ratio interposer. These thermal resistance temperature sensing elements comprise a graphene conductive network, which utilizes the temperature-dependent resistance of the network to achieve temperature sensing. Because the rigid rotating units primarily rotate during mechanical deformation, the temperature sensing elements are virtually unaffected by mechanical strain, effectively decoupling the temperature and mechanical deformation signals. The piezoelectric sensing layer utilizes a three-dimensional interconnected lead-free piezoelectric ceramic skeleton encapsulated in a flexible polymer matrix and attached with an array of stretchable electrodes. This design combines the high sensitivity of the piezoelectric material with the stretchability of the flexible matrix, enabling the piezoelectric sensing layer to effectively sense mechanical deformation. The base encapsulation layer utilizes a thick layer of flexible polymer, with an optimized thickness to keep the temperature and piezoelectric sensing layers away from the neutral axis of the sensor array. This increases the mechanical response sensitivity of the sensing layer, while further reducing the mutual interference between temperature and piezoelectric signals through physical distance isolation.

[0098] In specific implementation, the material of the three-dimensional interconnected lead-free piezoelectric ceramic framework is potassium sodium niobate, the microstructure is a three-dimensional porous network, and the crystal phase is a perovskite orthorhombic phase. The three-dimensional interconnected lead-free piezoelectric ceramic framework is prepared on a polymer foam template through a template-assisted sol-gel method and is formed after sintering. In the rotating square grid negative Poisson's ratio microstructure, the size of the rigid rotating unit is 1.5 mm x 1.5 mm, the rotating angle is 30°-45°, and the width of the flexible connection area is 0.2-0.5 mm.

[0099] In specific implementation, the top corner of the rigid rotating unit is completely covered by the flexible connection area to form a topologically continuous non-orthogonal hinge structure; and the center point of the rigid rotating unit coincides with that of the piezoelectric sensing unit. The top corner of the rigid rotating unit is completely covered by the flexible connection area to form a topologically continuous non-orthogonal hinge structure. This design enables the rigid unit to rotate around the contact point with the flexible connection area when subjected to external force, similar to the action of a hinge, but different from a traditional orthogonal hinge, which is more flexible in rotation direction and amplitude. This non-orthogonal hinge structure can effectively change the stress distribution. During mechanical deformation, the flexible connection area mainly bears tensile strain, while the rigid rotating unit mainly rotates, avoiding excessive tensile stress on the rigid unit, thereby protecting the temperature sensing unit on the rigid unit from interference signals caused by mechanical strain. The center point of the rigid rotating unit coincides with that of the piezoelectric sensing unit. This layout design enables the piezoelectric sensing unit to directly sense the local stress changes caused by the rotation of the rigid rotating unit during mechanical deformation, improving the sensitivity and accuracy of piezoelectric sensing. At the same time, this spatial correspondence also helps to accurately decouple temperature and mechanical deformation signals, as the temperature sensing unit is located at the top corner of the rigid rotating unit, and the piezoelectric sensing unit corresponds to the center of the rigid rotating unit. They are spatially related and independent, facilitating the collection and processing of different types of signals.

[0100] In specific implementation, the arrayed stretchable electrode is coated on the surface of the three-dimensional interconnected lead-free piezoelectric ceramic framework through a template printing process, and the electrode material is stretchable conductive silver paste. The arrayed stretchable electrode is coated on the surface of the three-dimensional interconnected lead-free piezoelectric ceramic framework through a template printing process. Template printing process is a high-precision and high-efficiency preparation method that can realize accurate patterning of electrode materials, ensuring good contact and electrical connection between the electrode and the piezoelectric ceramic framework. The electrode material is stretchable conductive silver paste. During mechanical deformation, the stretchable conductive silver paste can stretch or compress accordingly with the deformation of the piezoelectric ceramic framework and the flexible polymer matrix without breaking or falling off, ensuring stable electrical connection between the electrode and the piezoelectric ceramic framework.

[0101] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. Any features, such as preparation methods, materials, structures or composition ratios, connection structures, circuit structures, control methods, algorithms, etc., not explicitly described in this technical solution are considered to be common technical features disclosed in the prior art.

[0102] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0103] Before further describing the specific embodiments of the present invention, it should be understood that the scope of the present invention is not limited to the specific embodiments described below. It should also be understood that the terminology used in the examples is intended to describe specific embodiments and is not intended to limit the scope of the present invention. The experimental procedures in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0104] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the understanding of the prior art by those skilled in the art and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention may also be used to implement the present invention.

[0105] Example 1

[0106] This embodiment provides a method for preparing a multimodal sensor array, which includes the following steps:

[0107] (1) Preparation of KNN ceramic piezoelectric sensing layer: The KNN skeleton structure was prepared by a template-assisted sol-gel method, specifically including:

[0108] Potassium acetate and sodium acetate were dissolved in ethylene glycol methyl ether at a molar ratio of 0.48:0.52. Acetate was added at 3-10 mol% to compensate for sintering losses. Niobium ethoxide was dissolved in 2-methoxyethanol in a glove box, and acetylacetone was added to control the hydrolysis rate. The two solutions were combined and stirred for 6 hours and aged at room temperature for 24 hours to obtain a precursor sol with a concentration of 0.5 M. A polyurethane foam template with a thickness of 3 mm and a pore density of 40 ppi was fixed to the base of an ultrasonic sprayer and the KNN sol was applied using ultrasonic spraying technology. The spraying parameters were: frequency 80 kHz, air pressure 0.5 MPa, nozzle speed 20-50 mm / s, liquid flow rate 6-15 μL / s, spray width 8 mm, and 15 spraying passes on each side. The sprayed template was annealed at 1000°C to form the KNN ceramic skeleton.

[0109] (2) Piezoelectric layer polarization and electrode construction:

[0110] The KNN ceramic skeleton was cut into 6cm×6cm size and corona polarization treatment was performed for 40 minutes. PDMS was then cast to form a piezoelectric sensing layer. After the PDMS solidified, its surface was plasma treated, and a stretchable silver paste was template-printed to form an arrayed electrode pattern.

[0111] (3) Preparation of temperature sensing layer:

[0112] A conductive suspension was prepared by mixing PEDOT:PSS, sodium carboxymethyl cellulose (CMC), and graphene with deionized water in a mass ratio of 9:3:1:60. The suspension was ultrasonically treated for 12-24 hours and stirred for another 24 hours to ensure uniform dispersion. A 500μm-thick glass fiber (GFF)–PDMS composite membrane was processed into a negative Poisson's ratio structure using a CO2 laser platform and then plasma-treated. 3-8μL of the conductive suspension was drop-dispensed onto the stable, rigid regions of the structure and cured at 80°C-140°C to form the temperature sensing element. After electrical connections were established, a PDMS layer was encapsulated over the temperature sensor to protect it from external environmental interference.

[0113] (4) Integrated assembly of multimodal devices:

[0114] A 4mm thick PDMS substrate is used as the bottom layer, and a 3mm thick piezoelectric layer and a 500μm thick temperature sensing layer are bonded. Spin-coated PDMS is used as an adhesive. The piezoelectric unit and the temperature unit maintain a one-to-one correspondence in a 2×2 array unit. The PDMS base layer is used to distribute the sensing units away from the neutral axis to enhance the mechanical response sensitivity and achieve signal decoupling.

[0115] Figure 2Figures ab show the structural evolution of the KNN ceramic skeleton prepared from a PU foam template, characterized by optical microscopy. After sintering, the KNN ceramic successfully inherits the three-dimensional porous structure characteristics of the polymer foam template, retaining both the macroscopic interconnected skeleton structure and the microscale pore details. Notably, despite the high-temperature treatment, the resulting ceramic skeleton experiences minimal volume shrinkage, and the overall porous network structure remains intact. This dimensional stability is primarily attributed to the interconnected porous structure of the PU foam itself, which effectively alleviates the stress concentration problem commonly encountered during sintering.

[0116] Figure 3 ab are scanning electron microscope images of the KNN ceramic skeleton. Thanks to the precisely controlled sintering procedure, the obtained KNN skeleton presents a dense ceramic morphology with an average grain size of about 1 μm.

[0117] Figure 4 Figures ab are the X-ray diffraction patterns (XRD) and piezoelectric force microscopy test results of KNN ceramics. The XRD analysis was performed in the range of 20°–60° (2θ). The results showed that the sample presented a pure perovskite phase structure and no secondary phase diffraction peaks were found. The (220) and (002) diffraction peak intensity ratios at about 45° are 1 220 / I 002 ≈2:1, further confirming that the KNN ceramic is a single orthorhombic phase (O-phase) at room temperature. The piezoelectric behavior of the KNN skeleton was further characterized by piezoresponse force microscopy (PFM). Figure 4 As shown in Figure 2b, its phase-voltage curve exhibits clear polarization reversal behavior, with a phase change of nearly 180°, indicating that the material has switchable spontaneous polarization properties under the action of an applied electric field. The corresponding amplitude-voltage curve exhibits a typical "butterfly-shaped" response, indicating that the material has good electromechanical coupling and a significant polarization-dependent piezoelectric coefficient.

[0118] Figure 5 This is the output voltage of the piezoelectric device at the center of the device with a height of 5-20μm. It can be seen that when the distance from the top increases from 5 microns to 20 microns, the piezoelectric output increases from 6.74mV to 14.12mV.

[0119] Verification Example 1

[0120] The piezoelectric-piezoresistive multimodal sensing unit is fixed on all sides, and a small deformation is applied to the center of the sensor using the tip of a linear motor to observe the output performance of the sensor under different deformation sizes.

[0121] Figure 6 ab is the temperature curve of the temperature sensor, the logarithm of the normalized resistance ln(R / T 2) and the inverse of temperature (1 / T) show a clear linear relationship over a wide temperature range of 25°C to 130°C, strongly suggesting that its primary conduction mechanism conforms to the Small Polaron Hopping (SPH) model. The temperature sensor exhibited highly consistent resistance-temperature response characteristics over three heating cycles. As the temperature increased from 25°C to 130°C, the maximum resistance change rate reached approximately -65% (see Figure 4 a), thanks to the excellent heat resistance of the composite film.

[0122] Figure 7 The temperature-dependent output voltage response of the KNN-based piezoelectric sensing layer is demonstrated under a fixed applied force of 5 N. As the temperature rises to 110°C, the output voltage only slightly increases from 3.03 V to 3.14 V, consistent with the phase transition behavior observed in DSC analysis, indicating that the device's piezoelectric performance is stable within this temperature range.

[0123] Figure 9 The differential scanning calorimetry (DSC) curve of a KNN ceramic shows two distinct endothermic peaks at approximately 187°C and 397°C, corresponding to the orthorhombic to tetragonal (O–T) and tetragonal to cubic (T–C) phase transitions, respectively. Theoretically, near the O–T phase transition, piezoelectric performance improves slightly due to enhanced domain wall activity. However, after the T–C phase transition, the material transitions to a paraelectric state, leading to a sharp drop in piezoelectric performance. Therefore, to ensure thermal stability and functional reliability, KNN-based piezoelectric devices are designed to operate below 130°C.

[0124] Figure 8 Figures ab show the resistance change rate of the temperature sensor under different mechanical disturbance conditions (bending radius of 8.3–25.72 mm, applied pressure of 0.2–16 N). The results show that the resistance change rate is less than 0.1% under all conditions, indicating that mechanical disturbance has minimal impact on temperature sensing accuracy. This high resistance stability is mainly due to the negative Poisson's ratio structural design, which concentrates strain in the stretchable area and avoids stress on the rigid area. In addition, due to its small size (approximately 2 mm) and micron-level thickness, the PEDOT:PSS / CMC / graphene composite film has strong deformation resistance in both the lateral and thickness directions, further improving its stability in the thermal-mechanical decoupling sensing process.

[0125] Figure 9 The temperature-dependent output voltage response of the KNN-based piezoelectric sensing layer is demonstrated under a fixed applied force of 5 N. As the temperature rises to 110°C, the output voltage only slightly increases from 3.03 V to 3.14 V, consistent with the phase transition behavior observed in DSC analysis, indicating that the device's piezoelectric performance is stable within this temperature range.

[0126] Figure 10Figures ab and b are 3D finite element simulation models of the actual sample geometry, used to analyze the strain distribution during deformation. This model was constructed using COMSOL, and its geometry is consistent with the actual device. Figure 10 a shows that during bending, the strain is mainly distributed in the stretchable pore structure, while there is almost no strain distribution in the rigid square area. Figure 10 Figure b shows the displacement distribution of the piezoelectric layer in the Y direction when a bending displacement is applied along the –X edge of the structure in the –Z direction. The results show a positive displacement on the +Y side and a negative displacement on the –Y side, resulting in an overall lateral expansion characteristic along the Y axis. This lateral expansion is induced by the embedded negative Poisson's ratio structure and effectively transferred to the piezoelectric layer, generating in-plane tensile strain and effectively improving the electromechanical coupling efficiency of the piezoelectric film.

[0127] The deformation behavior in COMSOL uses a simplified cantilever beam configuration: one end is fixed, and the other end is subjected to vertical displacement. Compared to the complex natural bending situation, where the two ends and the middle move in an arched manner and the force direction changes continuously, this design is more conducive to the quantitative analysis of strain distribution.

[0128] Verification Example 2

[0129] Since artificially triggering a battery explosion in an experimental environment is highly dangerous, this verification example built a simulation platform to simulate the heat-induced deformation behavior of lithium-ion batteries during thermal runaway. The platform uses aluminum-plastic film soft package material (commonly used for battery packaging) to simulate the battery structure, simulates the heating process inside the battery through a heating plate, and injects air into the soft package with a syringe to reproduce the volume expansion phenomenon when the battery swells. Multimodal sensors are attached to the surface of the soft package to achieve simultaneous monitoring of temperature and deformation. First, the soft package is heated to 90°C to simulate the heat accumulation process, and then 3mL of air is injected to simulate the structural expansion caused by overheating, and the output of the multimodal sensor is observed.

[0130] Figure 11 The temperature sensors of the four units in ac show different resistance change trends during the heating process, but eventually they all stabilize at a fixed value (see Figure 11 c). The maximum resistance drops are –38.47%, –42.45%, –48.79% and –53.93%, corresponding to temperatures of 61.18°C, 66.69°C, 78.77°C and 89.71°C, respectively. The difference in response time and amplitude is mainly due to the spatial temperature difference caused by uneven heat conduction inside the soft package. During the temperature change period, the piezoelectric signal remains basically unchanged. When the soft package volume expands, the four units all experience a voltage increase of about 0.19V, corresponding to a strain of about 0.6% (see Figure 11 b), which is highly consistent with the actual deformation during the bulging process.

[0131] The foregoing description of the embodiments has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the application be limited not with this detailed description, but rather by the claims appended hereto.

Claims

1. A high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer, characterized in that: It includes a top packaging layer, a temperature sensing layer, a negative Poisson's ratio structure intermediary layer, a piezoelectric sensing layer, and a base packaging layer stacked in sequence from top to bottom, wherein: The negative Poisson's ratio structural intermediary layer is made of a high modulus flexible composite material, and the negative Poisson's ratio structural intermediary layer has a rotating square negative Poisson's ratio microstructure comprising a plurality of rigid rotating units and a flexible connection area; The temperature sensing layer includes a thermal resistance temperature sensing unit provided on the upper surface of the rigid rotating unit by dispensing, the thermal resistance temperature sensing unit is used to sense changes in ambient temperature, and the thermal resistance temperature sensing unit includes a graphene conductive network; The piezoelectric sensing layer includes a three-dimensional interconnected lead-free piezoelectric ceramic skeleton encapsulated in a flexible polymer matrix and an array of stretchable electrodes attached to the surface of the three-dimensional interconnected lead-free piezoelectric ceramic skeleton, thereby forming an array of piezoelectric sensing units. The piezoelectric sensing layer is used to sense mechanical deformation. The base packaging layer is composed of a thick layer of flexible polymer, and the thickness of the base packaging layer is configured to make the temperature sensing layer and the piezoelectric sensing layer away from the neutral axis of the sensing array; The operating temperature range of the multimodal flexible sensing array is 25°C to 130°C.

2. The high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer according to claim 1, characterized in that: The material of the three-dimensional interconnected lead-free piezoelectric ceramic skeleton is potassium sodium niobate, the microstructure is a three-dimensional porous network, and the crystal phase is a perovskite orthorhombic phase. The three-dimensional interconnected lead-free piezoelectric ceramic skeleton is prepared on a polymer foam template by a template-assisted sol-gel method and formed by sintering.

3. The high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer according to claim 1, characterized in that: The rigid rotation unit in the rotating square negative Poisson's ratio microstructure has a size of 1.5 mm × 1.5 mm, a rotation angle of 30°–45°, and a width of the flexible connection area of ​​0.2–0.5 mm; The top corners of the rigid rotating unit are completely covered by the flexible connection area, forming a topologically continuous non-orthogonal hinged structure; The center point of the rigid rotating unit coincides with the center point of the piezoelectric sensing unit.

4. The high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer according to claim 1, characterized in that: The arrayed stretchable electrodes are coated on the surface of the three-dimensional interconnected lead-free piezoelectric ceramic skeleton through a template printing process, and the electrode material is a stretchable conductive silver paste.

5. The high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer according to claim 1, characterized in that: The flexible polymer matrices of the top packaging layer, the base packaging layer, and the piezoelectric sensing layer are all made of polydimethylsiloxane.

6. A method for preparing a high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Preparation of piezoelectric sensing layer A three-dimensional interconnected lead-free piezoelectric ceramic skeleton is prepared by a template-assisted sol-gel method, specifically comprising: dissolving an alkali metal acetate and niobium ethoxide in an organic solvent at a predetermined ratio, adding a sintering compensator, stirring and aging the mixture to form a precursor sol, uniformly coating the precursor sol on the surface of a porous polymer template, and sintering the mixture to form a three-dimensional interconnected lead-free piezoelectric ceramic skeleton; Cutting the three-dimensional interconnected lead-free piezoelectric ceramic skeleton, polarizing it, and casting a flexible polymer package, and then printing a stretchable electrode array on the surface; S2: Integration of temperature sensing layer and negative Poisson's ratio structure intermediary layer Laser processing of rotating square negative Poisson's ratio microstructures on high modulus composite films enables the flexible connection area to completely cover the top corners of the rigid units to form non-orthogonal hinges; A conductive paste with a negative temperature coefficient response is applied to the upper surface of the rigid unit and solidified to form a thermal resistance temperature sensing unit; S3: Full device assembly spin coating the adhesive onto a thick layer of flexible polymer substrate; The piezoelectric sensing layer, the negative Poisson's ratio intermediary layer, and the temperature sensing layer are stacked in sequence, and the positioning and matching are performed so that the temperature sensing unit corresponds to the piezoelectric sensing unit in space; The flexible polymer encapsulation layer is covered and cured to obtain a high-temperature resistant multimodal flexible sensing array.

7. The high temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer according to claim 6, characterized in that: In S1, the specific steps of preparing the piezoelectric sensing layer include: dissolving potassium acetate and sodium acetate in a molar ratio of 0.48:0.52 in ethylene glycol methyl ether, adding 3-10 mol% of acetate to compensate for sintering losses, dissolving niobium ethoxide in 2-methoxyethanol, and adding acetylacetone to control the hydrolysis rate. Thereafter, the two solutions are combined and stirred for 6 hours, and aged at room temperature for 24 hours to obtain a precursor sol with a concentration of 0.5M; A polyurethane foam template with a thickness of 3 mm and a pore density of 40 ppi was fixed on the base of an ultrasonic spraying machine, and the precursor sol was sprayed using ultrasonic spraying technology. The spraying parameters were: frequency 80 kHz, air pressure 0.5 MPa, nozzle speed 20-50 mm / s, liquid flow rate 6-15 μL / s, spray width 8 mm, and 15 sprayings on both sides. Anneal the sprayed template at 1000°C for 40-90 minutes to form a three-dimensional interconnected lead-free piezoelectric ceramic skeleton; The three-dimensional interconnected lead-free piezoelectric ceramic skeleton was cut into 6 cm × 6 cm size and subjected to corona poling treatment for 40 min; Subsequently, PDMS packaging is cast to form a piezoelectric sensing layer. After the PDMS is solidified, plasma treatment is performed on its surface, and a stretchable silver paste is printed using a template to form an arrayed electrode pattern.

8. The high-temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer according to claim 6, characterized in that: In S2, the specific steps of integrating the temperature sensing layer with the negative Poisson's ratio structure intermediary layer include: PEDOT:PSS, sodium carboxymethyl cellulose, graphene and deionized water were mixed in a mass ratio of 9:3:1:60 to prepare a conductive suspension. The suspension was ultrasonically treated for 12-24 hours and stirred for 24 hours to ensure uniform dispersion. A 500 μm thick glass fiber-PDMS composite membrane was processed into a rotating square negative Poisson's ratio structure using a CO2 laser platform and then plasma treated. 3-8 μL of conductive suspension is dropped onto the rigid area of ​​the rotating grid negative Poisson's ratio structure using a dispensing method and cured at 80°C-140°C to form a temperature sensing unit; The temperature sensing unit is connected to the external circuit by wire bonding to ensure stable signal transmission. The PDMS layer is then encapsulated on the temperature sensor to obtain a composite structure integrating the temperature sensing layer and the negative Poisson's ratio structure intermediary layer.

9. The high temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer according to claim 6, characterized in that: In S3, the process of full device assembly includes: spin coating the adhesive onto a thick layer of flexible polymer substrate; The piezoelectric sensing layer, the negative Poisson's ratio structure intermediary layer, and the temperature sensing layer are stacked in sequence, and the thermal resistance temperature sensing units of the temperature sensing layer and the piezoelectric sensing units of the piezoelectric sensing layer are spatially aligned through positioning matching; Cover the top encapsulation layer and apply uniform pressure to make each functional layer tightly bonded; The material is cured to form a high-temperature resistant multimodal flexible sensing array.

10. An application of a high temperature resistant multimodal flexible sensing array based on a rotating negative Poisson's ratio structure interposer as claimed in any one of claims 1 to 5, characterized in that: The multimodal flexible sensing array is attached to the surface of a lithium-ion battery to simultaneously detect the surface temperature and mechanical deformation of the battery to identify abnormal conditions such as overheating and swelling of the battery. The specific method includes: A multimodal flexible sensing array is attached to the surface of the battery outer packaging; The heat accumulation process inside the battery is simulated by heating, and gas is injected into the battery to simulate the swelling phenomenon; Monitor the resistance change of the temperature sensing unit and the voltage output of the piezoelectric sensing unit; Based on the characteristic curves of temperature and voltage changes, determine whether the battery is in an abnormal state of overheating or swelling.

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