Thermoelectric temperature sensor insensitive to tensile strain

Abstract

According to the tensile strain insensitive thermoelectric temperature sensor provided by the invention, the snakelike lines on the two sides balance the tensile stress through a symmetrical structure, so that the deformation influence caused by stretching is remarkably reduced, the sensor keeps stable temperature sensing performance in various dynamic environments, the application range is wide, and the effect is remarkable; that is to say, the thermoelectric temperature sensor has good stretchable performance, the performance of the thermoelectric temperature sensor is basically kept unchanged before and after stretching, the structural design is reasonable, and the problems that an existing thermoelectric temperature sensor does not have the stretchable performance, and the sensing performance is prone to being affected by strain can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuits, and particularly relates to a stretch-strain-insensitive thermoelectric temperature sensor. Background Art

[0002] Stretchable and flexible temperature sensors can detect the temperature of human skin in real time, which provides the possibility for monitoring human health conditions in daily life. Thermoelectric power generation is an attractive technology that directly converts heat into voltage, and the voltage intensity is directly related to the change in temperature difference, enabling thermoelectric devices to achieve temperature sensing by monitoring the change in voltage signals. Therefore, thermoelectric temperature sensors have gradually attracted people's attention. With the development of wearable technology, the research on thermoelectric temperature sensors mainly focuses on being able to maintain stable temperature sensing performance while undergoing appropriate bending deformation, but not stretching. For example, Ma et al. studied a thin-film thermoelectric temperature sensor based on Ag2Se, and evaluated the flexibility of the sensor by performing bending tests at different angles. Although recent research has developed stretchable thermoelectric temperature sensors using material and structural innovations to adapt to mechanical stretching deformation, these sensors have certain problems, such as complex structures, high costs, and poor stability of temperature sensing performance under stretching conditions, which pose certain challenges for practical applications.

[0003] Existing thermoelectric temperature sensors can be bent, but do not have good stretchability, and have a greater impact on temperature sensing characteristics after stretching. Summary of the Invention

[0004] To solve the above problems, the present invention provides a stretch-strain-insensitive thermoelectric temperature sensor, which balances the tensile stress through a symmetric structure, effectively reduces the deformation caused by stretching to the sensor, enables the thermoelectric temperature sensor to still maintain the same temperature sensing performance as before stretching after stretching, and ensures that the voltage output is almost unchanged under the same temperature difference and is not affected by stretching.

[0005] A stretch-strain-insensitive thermoelectric temperature sensor is composed of a substrate and serpentine line structures symmetrically arranged on two sides of the substrate. Among them, the serpentine line structure includes alternately arranged P-type thermoelectric materials and N-type thermoelectric materials, and the P-type thermoelectric materials and N-type thermoelectric materials are connected through Cu electrodes.

[0006] Further, the P-type thermoelectric materials and N-type thermoelectric materials adopt a serpentine line structure, and the Cu electrodes are of a linear structure.

[0007] Further, the P-type thermoelectric material is Bi 0.5 Sb 1.5 Te3.

[0008] Further, the N-type thermoelectric material is Bi2Te 2.7 Se 0.3 .

[0009] Further, the material of the substrate is PDMS.

[0010] Further, the Cu electrodes on the same side are used as the cold end of the thermoelectric temperature sensor, and the Cu electrodes on the other same side are used as the hot end of the thermoelectric temperature sensor;

[0011] By applying different temperatures at the cold end and the hot end, the voltage difference ΔV and the temperature difference ΔT between the cold end and the hot end are obtained, and the ratio between the voltage difference ΔV and the temperature difference ΔT is used as the Seebeck coefficient S corresponding to the thermoelectric temperature sensor;

[0012] Keep the temperature of the cold end unchanged, and measure the voltage applied across both ends of the serpentine line structure. The temperature Ts of the hot end is obtained in real time through the Seebeck coefficient S, where Ts = T0 + ΔV / S, T0 is the temperature of the cold end, and Ts is the temperature of the hot end.

[0013] Beneficial effects:

[0014] The present invention provides a thermoelectric temperature sensor insensitive to tensile strain. The bilateral serpentine lines balance the tensile stress through a symmetric structure, significantly reducing the deformation influence caused by stretching, enabling the sensor to maintain stable temperature sensing performance in various dynamic environments, with a wide range of applications and remarkable effects; that is to say, the thermoelectric temperature sensor of the present invention has good stretchability, and the performance of the thermoelectric temperature sensor remains basically unchanged before and after stretching. The structural design is reasonable, and it can solve the problems that existing thermoelectric temperature sensors do not have stretchable characteristics and the sensing performance is easily affected by strain, etc. Description of the drawings

[0015] Figure 1 is a three-dimensional simulation model of the bilateral serpentine line sensor provided by the present invention;

[0016] Figure 2 is a top view of the three-dimensional simulation model of the bilateral serpentine line sensor provided by the present invention;

[0017] Figure 3 is a sectional view AA' of the three-dimensional simulation model of the bilateral serpentine line sensor provided by the present invention;

[0018] Figure 4 is a sectional view BB' of the three-dimensional simulation model of the bilateral serpentine line sensor provided by the present invention;

[0019] Figure 5 is a sectional view CC' of the three-dimensional simulation model of the bilateral serpentine line sensor provided by the present invention;

[0020] Figure 6The local enlarged view of the turning of the serpentine line of the three-dimensional simulation model of the bilateral serpentine line sensor provided by the present invention;

[0021] Figure 7 The three-dimensional simulation model of the unilateral serpentine line sensor provided by the present invention;

[0022] Figure 8 The displacement distribution diagram of the unilateral serpentine line sensor provided by the present invention stretched by 50%;

[0023] Figure 9 The displacement distribution diagram of the bilateral serpentine line sensor provided by the present invention stretched by 50%;

[0024] Figure 10 The original electric potential distribution diagram of the bilateral serpentine line sensor provided by the present invention under a temperature difference of 10K;

[0025] Figure 11 The electric potential distribution of the bilateral serpentine line sensor provided by the present invention stretched by 50% under a temperature difference of 10K;

[0026] Figure 12 The voltage response of the bilateral serpentine line sensor provided by the present invention at different strains under different temperature differences. Detailed implementation manners

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0028] A thermoelectric temperature sensor insensitive to tensile strain, as Figure 1 shown, is composed of a substrate and serpentine line structures symmetrically arranged on two sides of the substrate. Among them, as Figures 2 to 5 shown, the serpentine line structure includes alternately arranged P-type thermoelectric materials and N-type thermoelectric materials, and the P-type thermoelectric materials and the N-type thermoelectric materials are connected by Cu electrodes; among them, as Figure 6 shown, the P-type thermoelectric materials and the N-type thermoelectric materials adopt a serpentine line structure, and the Cu electrodes are in a linear structure.

[0029] It should be noted that for the three-dimensional structure, the present invention adopts a multi-physical field numerical simulation based on the finite element method to establish a three-dimensional model of the sensor, as Figure 7 shown; define the P-type thermoelectric material (Bi 0.5 Sb 1.5 Te3), the N-type thermoelectric material (Bi2Te 2.7 Se 0.3), parameters such as the Seebeck coefficient and conductivity of the electrode material (Cu) and the substrate material (PDMS), where the thermoelectric material adopts a serpentine structure and is only on one side of the substrate; determine the mesh precision division model and set the solver parameters; then perform finite element simulation; in the design of using a stretchable structure of serpentine on one side, although it is stretchable, its stretching effect is not good. As Figure 8 shown in the displacement distribution diagram of the one-sided serpentine sensor stretched by 50%, it can be clearly seen that it cannot meet the actual application.

[0030] It should be further noted that in the multi-physics field numerical simulation, consider the coupling simulation of multi-physics fields such as thermoelectric and structure, select the steady-state study, and establish a three-dimensional model of the sensor; in the solid heat transfer module, set the temperatures of the hot and cold ends; in the solid mechanics module, set the fixed constraints and specified displacements to achieve the uniaxial stretching of the sensor; set the Seebeck coefficient, conductivity and other parameters of Bi 0.5 Sb 1.5 Te3, Bi2Te 2.7 Se 0.3 , Cu and PDMS; then determine the mesh precision, refine it until the result has no obvious change and the use of time resources is less, and perform mesh division; then conduct research calculations, and draw images of the obtained results to obtain the voltage distribution, displacement distribution, etc.

[0031] That is to say, when the substrate is stretched along the length direction, the stretching causes deformation, and at the same time, small strains also occur in the bending parts of the serpentine line, resulting in deformation of the thermoelectric material. Although the structure of the one-sided serpentine line can be stretched, its stretching effect cannot reach the application level. In order to avoid the longitudinal deformation of the sensor during the stretching process, the structure of the sensor is changed to a double-sided serpentine line, as Figure 1 shown, its top view is as Figure 2 shown, and the cross-sectional view is as Figures 2 to 5 shown, so as to ensure that the stretching strain of the sensor is insensitive. Set the material, boundary conditions, mesh division, and then perform finite element simulation to obtain the displacement distribution diagram of the double-sided serpentine sensor stretched by 50%, the original electric potential distribution diagram at a temperature difference of 10K, the electric potential distribution diagram stretched by 50%, and the voltage response at different strains under different temperature differences, as Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 shown. It can be seen from this that under the determined temperature difference, the voltage difference of the thermoelectric temperature sensor provided by the present invention does not change with the change of strain, thus indicating the insensitivity of the thermoelectric temperature sensor of the present invention to stretching strain.

[0032] It should be noted that the working principle of the temperature sensor based on thermoelectric materials is based on the potential difference generated under different temperature gradients, that is, the Seebeck effect, and the voltage is directly related to the change in temperature difference.

[0033] In the Seebeck effect, the Seebeck coefficient is the key parameter connecting the temperature difference and the voltage. The Seebeck coefficient is defined as the ratio of the voltage to the temperature difference:

[0034] S = ΔV / ΔT

[0035] where ΔV and ΔT are the voltage difference and the temperature difference between the cold end and the hot end respectively. Since the magnitude of the voltage difference is proportional to the temperature difference, the temperature can be obtained from the voltage. If one end of the sensor maintains a constant temperature (T0), the real-time temperature (Ts) of the other end can be accurately deduced using Ts = T0 + ΔV / S.

[0036] Based on this, in the present invention, the Cu electrodes on the same side are used as the cold end of the thermoelectric temperature sensor, and the Cu electrodes on the other same side are used as the hot end of the thermoelectric temperature sensor; by applying different temperatures to the cold end and the hot end, the voltage difference ΔV and the temperature difference ΔT between the cold end and the hot end are obtained, and the ratio between the voltage difference ΔV and the temperature difference ΔT is used as the Seebeck coefficient S corresponding to the thermoelectric temperature sensor; keeping the cold end temperature unchanged and measuring the voltage applied across both ends of the serpentine line structure, the temperature Ts of the hot end is obtained in real time through the Seebeck coefficient S, where Ts = T0 + ΔV / S, T0 is the cold end temperature, and Ts is the hot end temperature.

[0037] The reasons why the thermoelectric temperature sensor provided by the present invention is insensitive to tensile strain are as follows:

[0038] As described above, the unilateral serpentine line structure is asymmetric. Due to this asymmetry, when the substrate is stretched, the thermoelectric material will produce out-of-plane warping on one side; the Seebeck coefficient is defined as the ratio of the voltage difference to the temperature difference: S = ΔV / ΔT; after stretching, the Seebeck coefficient of the thermoelectric temperature sensor provided by the present invention remains unchanged because the structural design of the bilateral serpentine line can produce large deformations. Its large deformations are not achieved by changing the thermoelectric material, but based on the symmetric structure of the bilateral serpentine line. Through the local small strain at the turning part of the serpentine line, the sensor undergoes tensile deformation along the length direction, and at the same time, the local small strain at the turning part of the serpentine line cancels each other out in the vertical direction along the substrate, that is, the out-of-plane warping generated on both sides cancels each other out. Therefore, the symmetric structure can effectively eliminate the out-of-plane deformation of the thermoelectric material caused by stretching of the sensor substrate while ensuring stretching. Due to this principle, there is almost no impact on the material itself, especially the thermoelectric material part; at the same time, the temperature difference remains unchanged. According to the formula of the Seebeck coefficient, the voltage difference generated by it will not change either. The sensor generates the same voltage difference under the same temperature difference, that is, the sensing performance of the sensor is not greatly affected by the tensile strain at both ends. This is the reason why the thermoelectric temperature sensor provided by the present invention is insensitive to tensile strain.

[0039] In summary, the present invention provides a thermoelectric temperature sensor that is insensitive to tensile strain. Compared with the unilateral serpentine line design, the bilateral serpentine line effectively eliminates the out-of-plane deformation caused by stretching of the sensor through a symmetric structure, ensuring the structural stability of the sensor and maintaining stable temperature sensing performance after stretching. Under the same temperature difference, the output voltage at both ends of the sensor hardly changes, making the application of the sensor hardly affected by the deformation caused by stretching.

[0040] Of course, the present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can certainly make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the appended claims of the present invention.

Claims

1. A thermoelectric temperature sensor insensitive to tensile strain, characterized in that, It consists of a substrate and serpentine line structures symmetrically arranged on two sides of the substrate. Among them, the serpentine line structure includes alternately arranged P-type thermoelectric materials and N-type thermoelectric materials, and the P-type thermoelectric materials and N-type thermoelectric materials are connected by Cu electrodes.

2. The stretch strain-insensitive thermoelectric temperature sensor according to claim 1, characterized in that, The P-type thermoelectric materials and N-type thermoelectric materials adopt a serpentine line structure, and the Cu electrodes are of a linear structure.

3. The stretch-strain insensitive thermoelectric temperature sensor according to claim 1, characterized in that, The P-type thermoelectric material is Bi 0.5 Sb 1.5 Te3.

4. A thermoelectric temperature sensor insensitive to tensile strain according to claim 1, characterized in that, The N-type thermoelectric material is Bi2Te 2.7 Se 0.3 .

5. The stretch strain-insensitive thermoelectric temperature sensor according to claim 1, characterized in that, The material of the substrate is PDMS.

6. The stretch-strain insensitive thermoelectric temperature sensor according to claim 1, characterized in that, The Cu electrodes belonging to the same side are used as the cold end of the thermoelectric temperature sensor, and the Cu electrodes belonging to the other side are used as the hot end of the thermoelectric temperature sensor; By applying different temperatures at the cold end and the hot end, the voltage difference ΔV and temperature difference ΔT between the cold end and the hot end are obtained, and the ratio between the voltage difference ΔV and the temperature difference ΔT is taken as the Seebeck coefficient S corresponding to the thermoelectric temperature sensor; Keep the cold end temperature unchanged, and measure the voltage applied across the serpentine line structure. The temperature Ts of the hot end is obtained in real time through the Seebeck coefficient S as Ts = T0 + ΔV / S, where T0 is the cold end temperature and Ts is the hot end temperature.

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