Thermal runaway pressure sensor for flexible lithium battery

Abstract

The invention provides a thermal runaway pressure sensor for a flexible lithium battery, and relates to the technical field of pressure sensors. The pressure sensor comprises a packaging layer, a first electrode layer, an interval supporting layer, a friction layer, a second electrode layer and a substrate layer which are sequentially stacked from top to bottom, the friction layer comprises a micro-structure array protruding towards the first electrode layer, the interval supporting layer and the micro-structure array are arranged in a spaced mode, and the interval supporting layer is arranged on the peripheral side of the micro-structure array in a surrounding mode. The height of the microstructure array is any value from 2 mm to 4 mm, the height difference between the interval supporting layer and the microstructure array is any value from 0 mm to 1.2 mm, and the Young modulus of the interval supporting layer is higher than that of the microstructure array. According to the pressure sensor, by regulating and controlling the height difference between the interval supporting layer and the friction layer and the Young modulus of the interval supporting layer, the pre-compression tolerance of the pressure sensor is improved, and meanwhile the high sensitivity and the wide detection interval of the pressure sensor are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensors, and particularly to a thermal runaway pressure sensor for flexible lithium batteries. Background Art

[0002] As a key energy component in the fields of new energy vehicles, energy storage systems, consumer electronics, etc., the safety of lithium batteries has attracted much attention. Thermal runaway is one of the most serious safety hazards of lithium batteries, usually caused by internal short circuits, overcharging, overheating or mechanical damage, resulting in a sharp increase in the internal temperature and pressure of the battery, and ultimately may lead to combustion or explosion, endangering life and property safety. During the thermal runaway process, the pressure change inside the battery is an important indicator reflecting its safety state. Therefore, real-time monitoring of the pressure change inside the lithium battery is of great significance for early warning of thermal runaway and improving battery safety.

[0003] However, in the prior art, the research on the internal pressure monitoring of lithium batteries mainly focuses on traditional pressure sensors and fiber optic sensors. Due to their large volume and high rigidity, traditional sensors are difficult to be embedded inside the battery, and are prone to cause stress concentration, affecting the battery performance. Although fiber optic sensors have the advantage of anti-electromagnetic interference, their high cost and complex installation make them difficult to be widely applied. There are also problems in the prior art that use thin film sensors and piezoresistive sensors to monitor and warn the pressure of lithium batteries, such as insufficient range or increased volume and reduced working efficiency due to the need for an external power supply. Summary of the Invention

[0004] An object of the present invention is to provide a thermal runaway pressure sensor for flexible lithium batteries, so as to solve the technical problem that the pressure sensors applicable to the thermal runaway monitoring of lithium batteries in the prior art cannot take into account high pressure resistance, high sensitivity and a wide detection range.

[0005] Another object of the present invention is to further widen the detection range of the pressure sensor.

[0006] According to the object of the present invention, the present invention provides a thermal runaway pressure sensor for flexible lithium batteries, which includes a packaging layer, a first electrode layer, a spacer support layer, a friction layer, a second electrode layer and a base layer that are sequentially stacked from top to bottom. The friction layer includes a microstructure array protruding towards the first electrode layer. The spacer support layer is arranged at an interval with the microstructure array and surrounds the periphery of the microstructure array. Among them,

[0007] the height of the microstructure array is any value from 2 mm to 4 mm, the material of the microstructure array is a porous flexible resin, the height difference between the spacer support layer and the microstructure array is any value from 0 to 1.2 mm, and the Young's modulus of the spacer support layer is higher than that of the microstructure array.

[0008] Optionally, the Young's modulus of the spacer support layer is any value in the range of 1900 kPa - 2500 kPa.

[0009] Optionally, the material of the spacer support layer is a mixture of an elastomeric material and a curing agent, and the mass ratio of the elastomeric material to the curing agent is any value in the range of 10:1 - 10:3.

[0010] Optionally, the elastomeric material is any one of polydimethylsiloxane, polyurethane, or acrylate.

[0011] Optionally, the porous flexible resin is a platinum-catalyzed silicone resin, and the microstructural array is obtained by a template method.

[0012] Optionally, the platinum-catalyzed silicone resin includes a platinum-catalyzed silicone resin component A and a platinum-catalyzed silicone resin component B, and the weight ratio of the platinum-catalyzed silicone resin component A to the platinum-catalyzed silicone resin component B is any value in the range of 0.8 - 1.2:1.

[0013] Optionally, the thickness of the first electrode layer and the second electrode layer is any value in the range of 40 μm - 60 μm.

[0014] Optionally, the materials of the first electrode layer and the second electrode layer are aluminum foils.

[0015] Optionally, the microstructural array includes a plurality of microstructures arranged at intervals, and the structure of the microstructures is any one of a pyramid shape, a conical shape, or a dome shape.

[0016] In the present invention, by arranging a spacer support layer on the periphery of the microstructural array of the friction layer, setting the height of the spacer support layer to be higher than the microstructural array by any value in the range of 0 - 1.2 mm, the Young's modulus of the spacer support layer being greater than that of the microstructural array, and setting the material of the microstructural array of the friction layer to be a porous flexible resin, while improving the pressure resistance of the spacer support layer, ensuring the pressure sensitivity of the microstructural array of the friction layer, optimizing the force distribution of the microstructural array during the operation of the pressure sensor and the mechanical properties of the overall pressure sensor, enabling it to have good pressure resistance and stability while having high sensitivity and a relatively wide detection range, being able to accurately identify pressure changes when a relatively large pressure has been applied, increasing the detection range of the pressure sensor, and precisely and quickly sending out warning information in the case of a sudden increase in pressure before the lithium battery reaches thermal runaway, preventing the lithium battery from undergoing thermal runaway and causing an explosion.

[0017] Furthermore, by setting the Young's modulus of the spacer support layer within the above range, the present invention can provide sufficient structural rigidity to prevent excessive deformation or collapse under pressure. That is, within the above Young's modulus range, the spacer support layer can provide a certain amount of support force without being overly rigid, thus allowing the microstructure array to generate sufficient deformation under external pressure, enabling the pressure sensor to have good sensitivity in both low-pressure and high-pressure ranges, accurately sensing the pressure changes when the lithium battery is approaching thermal runaway, and at the same time precisely controlling the deformation amplitude of the microstructure array in the friction layer to ensure the linearity of signal changes and improve the measurement range of the pressure sensor.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it in accordance with the content of the specification, the following takes the preferred embodiments of the present invention and describes them in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Some specific embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings in an exemplary but not restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0020] Figure 1 is a schematic structural diagram of a pressure sensor according to an embodiment of the present invention;

[0021] Figure 2 is a schematic installation diagram of the spacer support layer and the friction layer of a pressure sensor according to an embodiment of the present invention;

[0022] Figure 3 is an optical microscope image of a single microstructure according to an embodiment of the present invention;

[0023] Figure 4 is a graph of pressure vs. voltage of a pressure sensor with different spacer support layer heights according to an embodiment of the present invention;

[0024] Figure 5 is a graph of the stress-strain relationship of a pressure sensor being compressed multiple times according to an embodiment of the present invention;

[0025] Figure 6 is a graph of stress vs. strain of the spacer support layer according to an embodiment of the present invention.

[0026] Reference Numerals:

[0027] 100 - Pressure sensor, 10 - Encapsulation layer, 20 - First electrode layer, 30 - Spacer support layer, 40 - Friction layer, 50 - Second electrode layer, 60 - Substrate layer, 41 - Microstructure array, 42 - Substrate layer. Detailed implementation manners

[0028] The following will further describe in detail the specific implementation manners of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0029] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will make a detailed description of the specific implementation manners of the present application in conjunction with the accompanying drawings. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limiting the present application. Additionally, it should be noted that for the sake of convenience of description, only the parts related to the present application rather than all the structures are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present application.

[0030] The terms "including" and "having" in the present application and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0031] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears at various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0032] Figure 1 is a schematic structural diagram of a pressure sensor according to an embodiment of the present invention, Figure 2 is a schematic installation diagram of a spacer support layer and a friction layer of a pressure sensor according to an embodiment of the present invention, Figure 3 is an optical microscope image of a single microstructure according to an embodiment of the present invention.

[0033] As Figure 1 shown, the present invention provides a thermal runaway pressure sensor 100 for a flexible lithium battery. The pressure sensor 100 is suitable for being disposed inside the lithium battery or distributed among lithium battery packs to perform real-time pressure monitoring on the state of the lithium battery.

[0034] As Figure 1As shown, in this embodiment, the pressure sensor 100 includes a packaging layer 10, a first electrode layer 20, a spacing support layer 30, a friction layer 40, a second electrode layer 50 and a base layer 60 which are stacked from top to bottom, the friction layer 40 includes a microstructure array 41 protruding toward the first electrode layer 20, and the spacing support layer 30 is spaced apart from the microstructure array 41 and is arranged around the periphery of the microstructure array 41 (refer to Figure 2 ), wherein the height of the microstructure array 41 is any value in the range of 2 mm to 4 mm, the material of the microstructure array 41 is a porous flexible resin, the material of the microstructure array 41 is a porous flexible resin, the height difference between the spacing support layer 30 and the microstructure array 41 is any value in the range of 0 to 1.2 mm, and the Young's modulus of the spacing support layer 30 is higher than that of the microstructure array 41. Here, the height of the spacing support layer 30 is greater than the height of the microstructure array 41, and the height of the spacing support layer 30 is any value in the range of 2 mm to 5.2 mm, that is, the height of the spacing support layer 30 can be 2 mm, 2.1 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm or 5.2 mm, the height of the microstructure array 41 can be 2 mm, 2.5 mm, 3 mm, 3.5 mm or 4 mm, or any value in the range of 2 mm to 4 mm, and the friction layer 40 further includes a substrate layer 42, and the substrate layer 42 is disposed between the microstructure array 41 and the second electrode layer 50.

[0035] In this embodiment, by arranging a spacing support layer 30 on the peripheral side of the microstructure array 41 of the friction layer 40, the height of the spacing support layer 30 is set to be higher than any value of the microstructure array 410-1.2mm, the Young's modulus of the spacing support layer 30 is greater than the Young's modulus of the microstructure array 41, and the material of the microstructure array 41 of the friction layer 40 is set to a porous flexible resin, so as to improve the pressure resistance of the spacing support layer 30 while ensuring the pressure sensitivity of the microstructure array 41 of the friction layer 40, optimize the force distribution of the microstructure array 41 during the operation of the pressure sensor 100 and the overall mechanical properties of the pressure sensor 100, so that it has good pressure resistance and stability while having high sensitivity and a wide detection range, and can accurately identify pressure changes when a large pressure has been applied, thereby increasing the detection range of the pressure sensor 100, so as to accurately and quickly issue early warning information when the pressure suddenly increases before the lithium battery reaches thermal runaway, thereby preventing the lithium battery from exploding due to thermal runaway.

[0036] In this embodiment, the spacing support layer 30 with a high Young's modulus can provide uniform support when subjected to force, so that the microstructure array 41 can deform evenly when under pressure, avoiding measurement errors caused by excessive deformation in local areas or uneven force, improving the overall performance of the pressure sensor 100, and preventing the microstructure array 41 from excessive deformation or collapse, thereby ensuring that the sensor maintains stable working performance under different pressure conditions.

[0037] In this embodiment, when the height of the spacer support layer 30 is higher than the height of the micro-structure array 41, the pressure sensor 100 is subjected to a small pre-stress such that when the pressure sensor 100 is compressed, the first friction layer 40 first contacts the spacer support layer 30, so as to maintain the initial form of the micro-structure array 41 when the pressure sensor 100 is not subjected to significant external forces, avoid false triggering caused by environmental vibration or slight extrusion, and improve the accuracy and reliability of the pressure sensor 100. When a large pre-stress is detected, the degree of compression of the spacer support layer 30 under force is significantly increased, and since the material of the micro-structure array 41 is a multi-structure flexible resin, the micro-structure array 41 undergoes a large deformation, thereby improving the detection sensitivity of the pressure sensor 100 under high-pressure conditions and further improving the pressure resistance of the pressure sensor 100.

[0038] In this embodiment, when the height of the spacer support layer 30 is equal to the height of the micro-structure array 41, when the pressure sensor 100 is under force, the first friction layer 40 contacts both the spacer support layer 30 and the micro-structure array 41 of the friction layer 40. Since the Young's modulus of the spacer support layer 30 is greater than that of the micro-structure array 41, the spacer support layer 30 can provide uniform support when under force, so that the micro-structure array 41 can deform uniformly when compressed and has a high detection sensitivity under high-stress conditions.

[0039] In this embodiment, preparing the lithium battery thermal runaway pressure sensor 100 based on the triboelectric nanogenerator mechanism can reduce the power dependence and simplify the circuit system. That is, the triboelectric nanogenerator based on the triboelectrification and electrostatic induction mechanisms can directly convert mechanical force into electrical signals, avoiding the additional power circuit from increasing the complexity of the monitoring system.

[0040] In this embodiment, the height of the micro-structure array 41 is controllable, so that the response range of the pressure sensor 100 can be optimized through design to adapt to different pressure detection requirements.

[0041] In a further embodiment, the Young's modulus of the spacer support layer 30 is any value within 1900 kPa - 2500 kPa, that is, the height of the spacer support layer 30 can be 1900 kPa, 2000 kPa, 2100 kPa, 2300 kPa, or 2500 kPa, or also any value within 1900 kPa - 2500 kPa. By setting the Young's modulus of the spacer support layer 30 within the above range, sufficient structural rigidity can be provided so that it will not undergo excessive deformation or collapse under pressure. That is, within the above Young's modulus range, the spacer support layer 30 can provide a certain supporting force and is not overly rigid, thus allowing the microstructure array 41 to generate sufficient deformation under external pressure, enabling the pressure sensor 100 to have good sensitivity in both low-pressure and high-pressure ranges, accurately sensing the pressure changes when the lithium battery is approaching thermal runaway, and at the same time, precisely controlling the deformation amplitude of the microstructure array 41 in the friction layer 40, ensuring the linearity of signal changes, and increasing the measurement range of the pressure sensor 100.

[0042] In this embodiment, the material of the spacer support layer 30 with a Young's modulus within the above range is both flexible to a certain extent and durable enough to withstand multiple pressure cycles without experiencing structural fatigue or failure, and can maintain stable performance during long-term use, extending the service life, and is suitable for the scenario of long-term monitoring of lithium battery thermal runaway. Moreover, in the flexible battery structure, the rigidity within this range will neither damage the flexible characteristics of the battery nor ensure the effective support of the sensor, thereby enhancing its applicability and compatibility.

[0043] In a further embodiment, the material of the spacer support layer 30 is a mixture of an elastomeric material and a curing agent, and the mass ratio of the elastomeric material to the curing agent is any value within 10:1 - 10:3, that is, the mass ratio of the elastomeric material to the curing agent can be 10:1, 10:1.5, 10:2, 10:2.5, or 10:3, or also any value within 10:1 - 10:3. In this embodiment, a spacer support layer 30 with a Young's modulus of any value within 1900 kPa - 2500 kPa can be prepared when the mass ratio of the elastomeric material to the curing agent is within the above range. That is, by adjusting the mass ratio of the elastomeric material to the curing agent, the Young's modulus of the spacer support layer 30 can be regulated, thereby adjusting the stiffness of the spacer support layer 30 to prepare a spacer support layer 30 that meets the requirements of the prestress of the lithium battery and the detection sensitivity and detection range, enabling the preparation of the pressure sensor 100 to adapt to different environments and improving the reliability and applicability of the pressure sensor 100. Here, the volume ratio of the elastomeric material to the curing agent can be any value within 10:1 - 10:3, that is, the volume ratio of the elastomeric material to the curing agent can be 10:1, 10:1.5, 10:2, 10:2.5, or 10:3, or also any value within 10:1 - 10:3.

[0044] In a further embodiment, the elastomeric material is any one of polydimethylsiloxane, polyurethane or acrylate. In this embodiment, polydimethylsiloxane has excellent flexibility, and polyurethane can adjust its hardness and elasticity through different cross-linking degrees and ratios to meet the needs of the pressure sensor 100 in high sensitivity or high durability scenarios, and has higher impact resistance, which is suitable for scenarios with frequent pressure changes, such as high dynamic pressure monitoring. Acrylate has strong rigidity and can provide better support to prevent excessive deformation of the microstructure array 41 and improve signal stability. In a preferred embodiment, the elastomeric material is polydimethylsiloxane to prepare a pressure sensor 100 with high sensitivity and flexibility.

[0045] In a further embodiment, the porous flexible resin is a platinum-catalyzed silicone resin, and the microstructure array 41 is prepared according to the template method. In this embodiment, platinum-catalyzed silicone resin is used as a raw material, and the microstructure array 41 is prepared by the template method. Since the prepared microstructure array 41 has a porous structure, it has a low Young's modulus and high compressibility, and can produce a large deformation under the action of external pressure, thereby improving the sensitivity of the pressure sensor 100, so that it can detect small pressure changes. In addition, the platinum-catalyzed silicone resin has a high degree of cross-linking and good recovery, which can reduce deformation hysteresis and improve the stability and service life of the sensor. In addition, since the cross-linked network structure of the platinum-catalyzed silicone resin is more uniform, the prepared microstructure array 41 can maintain a high structural consistency, ensuring that the pressure sensor 100 can still maintain consistent mechanical properties when manufactured in different batches, thereby improving the repeatability and reliability of the pressure sensor 100.

[0046] In this embodiment, the template method can be used to prepare a microstructure array 41 with a specific morphology, which can accurately control the microstructure morphology and improve the response characteristics of the pressure sensor 100, so that the microstructure array 41 can produce uniform deformation when under pressure, thereby improving the signal consistency and reliability of the pressure sensor 100. Microstructures of different geometric shapes can also be prepared to optimize the deformation mode of the microstructure array 41 when under pressure, thereby adjusting the sensitivity, linearity and response range of the pressure sensor 100 to make it more suitable for different application scenarios.

[0047] In a further embodiment, the platinum-catalyzed silicone resin comprises a platinum-catalyzed silicone resin A component and a platinum-catalyzed silicone resin B component. The weight ratio of the platinum-catalyzed silicone resin A component to the platinum-catalyzed silicone resin B component is any value in the range of 0.8 - 1.2:1, that is, the weight ratio of the platinum-catalyzed silicone resin A component to the platinum-catalyzed silicone resin B component can be 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1, or can also be any value in the range of 0.8 - 1.2:1. In this embodiment, the A component usually contains a vinyl siloxane prepolymer and a platinum catalyst, and the B component usually contains a silicon hydride compound and an inhibitor. By adjusting the weight ratio of the A component to the B component within the above range, the crosslinking degree, mechanical properties, microstructure morphology and the performance of the pressure sensor 100 of the silicone resin can be changed, so that the prepared microstructure array 41 simultaneously has a large deformation response force and an elastic deformation recovery ability. That is, as the proportion of the vinyl siloxane prepolymer in the A component increases, the crosslinking density of the silicone resin decreases, and the prepared microstructure array 41 is more flexible and easier to deform, so that a large deformation can be generated under low pressure, improving the low-pressure response ability of pressure detection. As the relative amount of the silicon hydride compound in the B component increases, the internal crosslinking structure of the silicone resin becomes more compact, making the material harder, with less deformation and a faster recovery speed, improving the support ability of the microstructure array 41, preventing the accumulation or collapse of deformation of the microstructure array 41 after long-term use, and enhancing the service life of the pressure sensor 100.

[0048] In this embodiment, when the content of the A component is relatively large, the microstructure array 41 is more likely to deform when pressed, but the recovery time is longer, which may cause a certain hysteresis effect, and it is suitable for low-pressure detection and long-term pressure monitoring. When the B component is relatively large, the microstructure array 41 is more resistant to deformation and can quickly return to the initial state after being stressed, improving the response speed and long-term stability of the sensor, and it is suitable for high-dynamic pressure detection. Here, the mass ratio of the A component and the B component of the platinum-catalyzed silicone resin can be adjusted according to the detection sensitivity requirement and the support force requirement. Regarding the mass ratio of the A component and the B component, no limitation is made here.

[0049] In a further embodiment, the thicknesses of the first electrode layer 20 and the second electrode layer 50 are any value in the range of 40 μm - 60 μm, that is, the thicknesses of the first electrode layer 20 and the second electrode layer 50 can be 40 μm, 45 μm, 50 μm, 55 μm, or 60 μm, or any value in the range of 40 μm - 60 μm. By setting the thicknesses of the first electrode layer 20 and the second electrode layer 50 within the above range, the deformation ability of the pressure sensor 100 can be enhanced, the micro-pressure sensing performance can be improved, the conductivity can be optimized, the stability of signal transmission can be ensured, and the noise interference can be reduced. In this embodiment, when the thicknesses of the first electrode layer 20 and the second electrode layer 50 increase, the resistance decreases, the conductivity is better, which helps to reduce signal loss and improve the detection accuracy. When the thicknesses of the first electrode layer 20 and the second electrode layer 50 decrease, the flexibility is better, which can adapt to minute pressure changes and improve the low-pressure detection sensitivity. Here, there are no restrictions on the thicknesses of the first electrode layer 20 and the second electrode layer 50, and they can be selected according to the detection accuracy requirements.

[0050] In a further embodiment, the materials of the first electrode layer 20 and the second electrode layer 50 are aluminum foils. By setting the materials of the first electrode layer 20 and the second electrode layer 50 as aluminum foils, the internal resistance of the pressure sensor 100 can be effectively reduced, signal loss can be decreased, the sensitivity and stability of pressure detection can be improved, the detection accuracy of the sensor can be enhanced, and minute pressure changes can be accurately sensed. In addition, aluminum foils have high tensile strength and tear resistance. Even in a thin-layer structure, they can provide sufficient mechanical support, prevent the pressure sensor 100 from being damaged during long-term use, improve the fatigue resistance and durability, extend the service life of the pressure sensor 100, and are suitable for long-term monitoring scenarios.

[0051] As Figure 3 shown, in a further embodiment, the microstructure array 41 includes a plurality of microstructures arranged at intervals, and the structure of the microstructures is any one of a pyramid shape, a conical shape, or a dome shape. By arranging a plurality of microstructures in an array, the force uniformity of the friction layer 40 can be improved, thereby ensuring signal stability. Microstructures with different structures have different pressure sensing sensitivities and compressive abilities, and the microstructures with corresponding structures can be selected according to the detection requirements.

[0052] In this embodiment, the height value of the spacer support layer 30 is determined based on simulation design and the deformation characteristics of the microstructure array 41 of the friction layer 40. Since the microstructure array 41 will deform under pressure, if the height of the spacer support layer 30 is too high, its regulation effect may not match the deformation behavior of the microstructure array 41. Therefore, the height selection needs to match the deformation degree of the microstructure array 41 to optimize the detection sensitivity and detection range of the pressure sensor 100. Within the above height range, the spacer support layer 30 can effectively regulate the deformation behavior of the microstructure array 41. By comprehensively simulating the simulation results and material properties, the height combination is finally determined to achieve the best performance of the pressure sensor 100.

[0053] In this embodiment, the specific applicable scenarios of the pressure sensor 100 are extensive. It can be set inside a single lithium battery or between lithium battery packs. In actual application scenarios, the pressure sensor 100 in this embodiment can provide accurate and stable real-time pressure monitoring of lithium battery thermal runaway for large-scale energy storage devices such as new energy vehicles, energy storage systems, and large unmanned devices.

[0054] In this embodiment, the pressure sensor 100 is used to monitor the pressure change during the thermal runaway of the battery in real time. To achieve effective monitoring and data analysis, an additional circuit processing system is required. The system includes a signal conditioning circuit, an analog-to-digital conversion module, a microcontroller (MCU) or a digital signal processor (DSP), a display module, and a communication module. The signal conditioning circuit processes the analog signal output by the sensor through amplification and filtering. The analog-to-digital conversion module converts the analog signal into a digital signal. The MCU / DSP analyzes and processes the digital signal to determine whether the battery is in a thermal runaway state, and the display module displays the pressure state and health state of the battery in real time. The communication module can transmit the pressure data and battery status to the cloud or monitoring center in real time, generate a visual battery status report, and trigger an alarm mechanism when an abnormality is detected. This circuit processing system can provide an important guarantee for the safe operation of the battery and is applicable to fields such as electric vehicles and energy storage systems.

[0055] The present application will be further described in detail below with reference to specific embodiments.

[0056] Embodiment 1

[0057] The thermal runaway pressure sensor 100 for flexible lithium batteries includes a packaging layer 10, a first electrode layer 20, a spacer support layer 30, a friction layer 40, a second electrode layer 50, and a base layer 60 that are stacked in sequence from top to bottom. The friction layer 40 includes a microstructure array 41 that protrudes toward the first electrode layer 20. The spacer support layer 30 is disposed at an interval from the microstructure array 41 and surrounds the periphery of the microstructure array 41. Among them, the height of the microstructure array 41 is 3 mm, the height of the spacer support layer 30 is 4 mm, and the Young's modulus of the spacer support layer 30 is 2000 kPa.

[0058] Example Two

[0059] The difference between Example Two and Example One is only that the height of the spacer support layer 30 is 3 mm.

[0060] Comparative Example One

[0061] The difference between Comparative Example One and Example One is only that the height of the spacer support layer 30 is 0 mm.

[0062] The pressure sensors 100 obtained by preparing the above Example One, Example Two, and Comparative Example One are tested for sensitivity and detection range.

[0063] Figure 4 It is a graph of pressure vs. voltage of the pressure sensor 100 with different heights of the spacer support layer 30 according to an embodiment of the present invention.

[0064] As Figure 4 shown, the pressure sensor 100 obtained by preparing Example Two is divided into two regions within the measured pressure range: a low sensing sensitivity region with a pressure range of 0 - 800 kPa, and a high sensing sensitivity region with a pressure range of 800 kPa - 1000 kPa and above. The linearity of the signals in both detection regions remains at a performance of R > 0.99. In addition, it can be seen that after being subjected to a pressure of 800 kPa, the sensing sensitivity shows an upward trend, which indicates that when the height difference and deformation behavior between the spacer support layer 30 and the microstructure array 41 in Example Two match, the regulation effect takes effect, and the pressure sensor 100 has high sensing performance. And in this case, the pressure sensor 100 has high adaptability to sensing under large pre - pressures, meeting the high - prestress environment requirements when assembled inside a lithium battery or arranged between lithium battery packs. Compared with Comparative Example One without the spacer support layer 30, both Example One and Example Two have a higher detection range and detection sensitivity under high - prestress conditions.

[0065] Figure 5 It is a graph of the stress - strain relationship of the pressure sensor 100 being compressed multiple times according to an embodiment of the present invention.

[0066] As Figure 5As shown, the pressure sensor 100 obtained in Embodiment 1 of the present invention can be compressed to 80% of its initial thickness, and after undergoing five compression and rebound cycles, its stress-strain curve shows no obvious change. The behavior of the slight change in the stress-strain curve indicates that the pressure sensor 100 of this embodiment has excellent stability and durability, can maintain its structural integrity under multiple external stimuli, and will not affect its performance stability due to repeated operation, and is suitable for application scenarios that require long-term stable monitoring.

[0067] Figure 6 is a graph of the stress and strain of the spacer support layer 30 according to an embodiment of the present invention.

[0068] As Figure 6 shown, the Young's modulus of the material for preparing the friction layer 40 in Embodiment 1 is 88 kPa, and the Young's modulus of the spacer support layer 30 is 1912 kPa, which is greater than that of the material for preparing the friction layer 40. The difference in Young's modulus between the two will affect the regulation effect of the spacer support layer 30, thereby affecting the optimal height combination in the implementation.

[0069] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0070] The above-described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A thermal runaway pressure sensor for a flexible lithium battery, characterized in that It includes a packaging layer, a first electrode layer, a spacer support layer, a friction layer, a second electrode layer, and a base layer that are stacked in sequence from top to bottom. The friction layer includes a microstructure array that protrudes toward the first electrode layer. The spacer support layer is spaced from the microstructure array and surrounds the periphery of the microstructure array. Among them, the height of the microstructure array is any value between 2 mm and 4 mm, the material of the microstructure array is a porous flexible resin, the height difference between the spacer support layer and the microstructure array is any value between 0 and 1.2 mm, and the Young's modulus of the spacer support layer is higher than that of the microstructure array.

2. The pressure sensor according to claim 1, wherein the Young's modulus of the spacer support layer is any value between 1900 kPa and 2500 kPa.

3. The pressure sensor according to claim 2, wherein the material of the spacer support layer is a mixture of an elastomeric material and a curing agent, and the mass ratio of the elastomeric material to the curing agent is any value between 10:1 and 10:

3.

4. The pressure sensor according to claim 3, wherein the elastomeric material is any one of polydimethylsiloxane, polyurethane, or acrylate.

5. The pressure sensor according to claim 4, wherein the porous flexible resin is a platinum-catalyzed silicone resin, and the microstructure array is obtained by preparation according to the template method.

6. The pressure sensor according to claim 5, wherein the platinum-catalyzed silicone resin includes a platinum-catalyzed silicone resin A component and a platinum-catalyzed silicone resin B component, and the weight ratio of the platinum-catalyzed silicone resin A component to the platinum-catalyzed silicone resin B component is any value between 0.8 and 1.2:

1.

7. The pressure sensor according to any one of claims 1-6, wherein the thickness of the first electrode layer and the second electrode layer is any value between 40 μm and 60 μm.

8. The pressure sensor according to claim 7, wherein the materials of the first electrode layer and the second electrode layer are aluminum foils.

9. The pressure sensor according to claim 8, characterized in that, The microstructure array includes a plurality of spaced microstructures, and the structure of the microstructures is any one of a pyramid shape, a conical shape, or a dome shape.

Images