Flexible temperature-pressure dual-mode sensor for battery expansion force detection

Abstract

The utility model provides a flexible temperature-pressure dual-mode sensor for battery expansion force detection. The flexible temperature-pressure dual-mode sensor comprises an upper-layer substrate, a pressure sensitive layer, an upper temperature sensitive layer, an electrode layer, a middle-layer substrate, a lower temperature sensitive layer and a lower-layer substrate which are sequentially arranged from top to bottom, the electrode layer comprises a pressure sensing electrode layer and a temperature sensing electrode layer; the pressure spacing layer is connected with the upper-layer substrate and the middle-layer substrate so as to form a space between the upper-layer substrate and the middle-layer substrate, the pressure sensing electrode layer is arranged on the middle-layer substrate, and the pressure sensitive layer and the pressure sensing electrode layer are separated from each other; the upper temperature sensitive layer and the lower temperature sensitive layer are connected in series through the temperature sensing electrode layer. By applying the technical scheme, the flexible temperature-pressure dual-mode sensor for detecting the expansion force of the battery can be provided, the temperature and pressure changes during expansion of the battery can be accurately measured, the process complexity is reduced, and the practical application range is widened.

Description

Technical Field

[0001] The utility model relates to the field of flexible sensors, in particular to a flexible temperature-pressure dual-mode sensor for detecting battery expansion force. Background Art

[0002] With the continuous advancement of technology and the expansion of its application areas, flexible sensor technology is rapidly developing, gradually becoming more diversified, integrated, and miniaturized, and demonstrating its importance and potential in multiple fields. In today's new energy battery sector, in particular, flexible sensors provide important support for safe, efficient, and intelligent battery management. For example, by monitoring the stress on the battery edge, it is possible to understand the battery's expansion during charging and analyze its safety accordingly.

[0003] The rapid development of the new energy battery field has also put forward higher requirements on the performance of flexible sensors. Flexible sensors with a single parameter are difficult to meet market demand, and the demand for sensors that can simultaneously detect multiple physical quantities (such as temperature and pressure) is increasing. In order to better monitor the expansion force on the outer surface and inside of the battery and provide a real-time data basis for battery design optimization, improvement and safety monitoring, current research is gradually developing from single-parameter sensing to multi-modal integrated sensing, such as dual-modal flexible sensors that can simultaneously sense temperature and pressure. This type of sensor can provide richer environmental perception information, monitor the status of the battery in real time, and prevent safety problems caused by overheating or excessive expansion.

[0004] Most of the existing common battery expansion force detection sensors do not have temperature measurement and compensation, making it difficult to achieve accurate expansion pressure evolution. There are limitations in achieving accurate decoupling of pressure and temperature dual moduli under complex temperature gradient distribution interference conditions, which restricts their widespread use in practice.

[0005] In summary, in order to accurately measure the temperature and pressure changes during battery expansion, reduce process complexity, and increase the scope of practical application, it is necessary to design and develop a flexible temperature-pressure dual-mode sensor for battery expansion force detection. Utility Model Content

[0006] The purpose of the present utility model is to overcome the deficiencies in the above-mentioned prior art and provide a flexible temperature-pressure dual-mode sensor for detecting battery expansion force, which accurately measures the temperature and pressure changes during battery expansion, reduces process complexity, and increases the scope of practical application.

[0007] In order to solve the above technical problems, the utility model provides a flexible temperature-pressure dual-mode sensor for detecting battery expansion force, comprising an upper substrate, a pressure-sensitive layer, an upper temperature-sensitive layer, an electrode layer, an intermediate substrate, a lower temperature-sensitive layer, and a lower substrate, arranged in order from top to bottom; the electrode layer includes a pressure sensing electrode layer and a temperature sensing electrode layer;

[0008] a pressure spacer layer connecting the upper substrate and the middle substrate to form a certain space between the upper substrate and the middle substrate, wherein the pressure sensitive layer and the pressure sensing electrode layer are arranged in the space, the pressure sensitive layer is arranged on the upper substrate, the pressure sensing electrode layer is arranged on the middle substrate, and the pressure sensitive layer is spaced apart from the pressure sensing electrode layer;

[0009] The upper temperature sensitive layer and the lower temperature sensitive layer have the same structure and are symmetrically arranged on the upper and lower sides of the intermediate layer substrate. The upper temperature sensitive layer and the lower temperature sensitive layer are connected in series through the temperature sensing electrode layer.

[0010] In a more preferred embodiment, the upper substrate includes an upper hollow hole corresponding to the shape and position of the upper temperature-sensitive layer; and the lower substrate includes a lower hollow hole corresponding to the shape and position of the lower temperature-sensitive layer.

[0011] In a more preferred embodiment, it also includes an upper temperature-sensitive layer protective layer and a lower temperature-sensitive layer protective layer, wherein the upper temperature-sensitive layer protective layer is arranged on the upper side of the intermediate layer substrate and completely covers the upper temperature-sensitive layer, and the lower temperature-sensitive layer protective layer is arranged on the lower side of the intermediate layer substrate and completely covers the lower temperature-sensitive layer.

[0012] In a more preferred embodiment, the area of ​​the upper temperature-sensitive layer protective layer is larger than that of the upper temperature-sensitive layer; the area of ​​the lower temperature-sensitive layer protective layer is larger than that of the lower temperature-sensitive layer.

[0013] In a more preferred embodiment, the upper temperature-sensitive layer protection layer and the lower temperature-sensitive layer protection layer are made of silicon dioxide, boron nitride, boron oxide, and aluminum oxide.

[0014] In a more preferred embodiment, the upper temperature-sensitive layer, the lower temperature-sensitive layer, the upper temperature-sensitive layer protection layer, and the lower temperature-sensitive layer protection layer are all made by magnetron sputtering.

[0015] In a more preferred embodiment, the upper temperature sensitive layer is arranged radially outside the pressure sensitive layer.

[0016] In a more preferred embodiment, it further comprises an upper adhesive layer, wherein the upper adhesive layer is adhesively connected to the upper substrate and the middle substrate.

[0017] In a more preferred embodiment, the upper substrate, the middle substrate and the lower substrate are made of polyimide, polyethylene terephthalate, polyetherimide or polyamide-imide; the electrode layer is made of copper, gold, liquid metal or silver nanowires; the electrodes are made by screen printing, magnetron sputtering or laser etching; the pressure sensitive layer is made of thermoplastic polyurethane or polydimethylsiloxane mixed with any one of graphene, carbon nanotubes and carbon black; and the pressure spacer layer is made of green oil paint or boron nitride.

[0018] Compared with the existing technology, the technical solution of the utility model has the following beneficial effects:

[0019] The flexible temperature-pressure dual-mode sensor provided by the present invention consists of two components: a temperature sensor and a pressure sensor. First, the sensor is made entirely of flexible materials, enhancing its flexibility and toughness. Second, compared to existing battery expansion force sensors, the sensor provided by the present invention expands the analysis of temperature parameters to achieve dual-mode detection, reducing temperature interference during battery expansion force detection, improving analysis efficiency, expanding the linear range of detection, and enhancing accuracy and application flexibility. Third, the sensor provided by the present invention, from material to structural design, takes into account the impact of harsh application environments during battery testing, improving the sensor's overall resistance to stress and providing guidance for practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the flexible temperature-pressure dual-mode sensor described in the present utility model;

[0021] Figure 2 This is a schematic diagram of the dimensions of each part of the sensor described in the present utility model;

[0022] Figure 3 This is a schematic structural diagram of the pressure sensor of the present utility model;

[0023] Figure 4 This is the measurement principle diagram of the pressure sensor of the present utility model;

[0024] Figure 5 This is a schematic diagram of the structure of the temperature sensor of the present utility model;

[0025] Figure 6 This is a schematic diagram of the anti-interference implementation principle of the temperature sensor of the present utility model;

[0026] Figure 7 This is a schematic diagram of the sensor application described in the present utility model. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] Certain directional terms used in the following description of the drawings, such as "inner," "outer," "above," "below," and other directional terms, should be understood to have their normal meanings and refer to those directions when the drawings are normally viewed. Unless otherwise indicated, the directional terms used in this specification are generally in accordance with conventional directions understood by those skilled in the art.

[0029] The terms "first", "first", "second", "second" and similar terms used in this utility model do not indicate any order, quantity or importance, but are used to distinguish one component from other components.

[0030] The purpose of the present invention is to provide a flexible temperature-pressure dual-mode sensor for detecting battery expansion force, so as to achieve the goal of accurately measuring the temperature and pressure changes during battery expansion and improve the practical application range.

[0031] Figure 1 This is a schematic diagram of the structure of the flexible temperature-pressure dual-mode sensor described in the present invention, as shown in FIG. Figure 1 As shown, the sensor is arranged from top to bottom in the following order: upper substrate 1, upper adhesive layer 2, pressure sensitive layer 3, pressure spacer layer 4, upper temperature sensitive layer protective layer 5, upper temperature sensitive layer 6, electrode layer 7, intermediate substrate 8, lower temperature sensitive layer 9, lower temperature sensitive layer protective layer 10, and lower substrate 11. The electrode layer 7 includes a pressure sensing electrode layer and a temperature sensing electrode layer.

[0032] Optionally, the material of the upper substrate 1, the middle substrate 8, and the lower substrate 11 can be any one of polyimide (PI), polyethylene terephthalate (PET), polyetherimide (PEI), and polyamide-imide (PAI). These materials need to have good flexibility, high tensile strength, corrosion resistance, good electrical insulation properties, and chemical stability, and be easy to process to meet the design requirements of various sensors.

[0033] Optionally, the material of the electrode layer 7 can be any one of copper (Cu), gold (Au), liquid metal and silver nanowires (AgNWs). The pressure sensing electrode is an interdigitated electrode and needs to have excellent electrical conductivity.

[0034] Alternatively, the electrode layer 7 can be prepared by screen printing, magnetron sputtering, or laser etching. However, the process to be selected depends on the type of electrode. For liquid metal and silver nanowires, screen printing can be used for electrode preparation; for metal materials such as gold or copper, either magnetron sputtering or laser etching can be used for preparation.

[0035] Figure 2 This is a schematic diagram of the dimensions of each part of the sensor described in this utility model, as shown in Figure 2 As shown, the dimensions, from small to large, are: electrode layer 7, pressure spacer layer 4, pressure sensitive layer 3, upper temperature sensitive layer 6 or lower temperature sensitive layer 9, upper temperature sensitive protective layer 5 or lower temperature sensitive protective layer 10, upper adhesive layer 2, upper substrate 1 or lower substrate 11, and intermediate substrate 8. The dimensions of the layers do not need to be strictly aligned; a certain spacing tolerance is required for ease of operation.

[0036] Figure 3 FIG. 1 is a schematic structural diagram of the pressure sensing portion of the flexible temperature-pressure dual-mode sensor of the present invention; FIG. Figure 3 As shown, the pressure sensing part includes the upper substrate 1, the pressure sensitive layer 3, the pressure spacer layer 4, the pressure sensing electrode layer of the electrode layer 7 and the intermediate substrate 8, which are arranged in sequence from top to bottom, wherein the thickness of the pressure spacer layer 4 needs to be greater than the pressure sensitive layer to ensure that there is a certain distance between the pressure sensitive layer 3 and the pressure sensing electrode layer.

[0037] The pressure sensing electrode layer, including the lead-out wires, is disposed on the upper surface of the intermediate substrate 8, aiming to improve the overall integration of the sensor. The upper substrate 1 and the lower substrate 11 cannot completely cover the temperature-sensitive area, particularly the electrodes in the temperature-sensitive layer, which would reduce the sensitivity of the temperature sensor. Therefore, the upper and lower substrates 1 and 11 need to be hollowed out at the locations corresponding to the temperature-sensitive electrodes to form upper and lower hollow holes, respectively. The upper and lower substrates 1 and 11 can be cut using a laser etching process to obtain the desired substrate shape.

[0038] The material of the upper adhesive layer 2 can be any one of a self-adhesive adhesive and an epoxy resin adhesive. It needs to have a certain viscosity and flexibility so that the upper substrate 1 and the middle substrate 8 can be better fixed together.

[0039] The pressure-sensitive layer 3 can be made of any material such as thermoplastic polyurethane (TPU) or polydimethylsiloxane (PDMS) mixed with graphene (GR), carbon nanotubes (CNT), or carbon black (CB). It must have a certain degree of conductivity and, after curing, a certain resistance value can be measured.

[0040] The pressure spacer layer 4 can be made of either green oil paint or boron nitride (BN). It must be non-sticky after solidifying at room temperature and possess a certain degree of toughness. Its primary function is to separate the pressure-sensitive layers 6 and 9 from the intermediate substrate 8. Its purpose is to improve the sensitivity of the pressure sensor.

[0041] The upper adhesive layer 2, the pressure sensitive layer 3 and the pressure spacer layer 4 are prepared by screen printing.

[0042] The core of the pressure spacer layer 4 in improving the pressure sensing sensitivity is that it reduces the initial contact area between the pressure sensitive layer 3 and the pressure sensing electrode layer, but has no effect on the contact area after it is pressurized. Since the resistance of the piezoresistive pressure sensor decreases after being pressurized, it is tentatively determined that R0 = ΔR + ΔR'. Regardless of whether there is a spacer layer or not, ΔR' remains almost unchanged when a certain pressure is applied. However, after adding the pressure spacer layer 4, both R0 and ΔR will increase. According to the sensitivity formula

[0043] S=ΔR / (R0·ΔP)=(1-ΔR′ / R0) / ΔP

[0044] It can be seen that adding the pressure spacer layer 4 increases the sensitivity (S).

[0045] Figure 4 The diagram is a measurement principle diagram of the pressure sensing portion of the flexible temperature-pressure dual-mode sensor of the present invention; Figure 4 As shown, after the battery cell expands, the distance between the pressure sensitive layer 3 and the electrode layer 7 becomes smaller and contact occurs, resulting in a smaller resistance between the electrodes. The greater the expansion pressure, the larger the contact area and the smaller the output resistance. The expansion pressure of the battery cell is detected by detecting its resistance change. In particular, the output resistance of the pressure sensing part is linearly related to the pressure and shows a negative growth trend, that is, the greater the pressure, the smaller the output resistance. In the actual implementation process, the actual pressure value can be obtained by detecting the resistance at both ends of the pressure sensing electrode layer and then inverting the pressure based on the relationship between the sensor resistance and pressure.

[0046] Figure 5 Schematic diagram of the temperature sensing portion of the flexible temperature-pressure dual-mode sensor of the present invention; Figure 5As shown, the temperature sensing part includes the upper temperature sensitive layer protective layer 5, the upper temperature sensitive layer 6, the intermediate layer substrate 8, the lower temperature sensitive layer 9 and the lower temperature sensitive layer protective layer 10, which are arranged in sequence from top to bottom. The upper temperature sensitive layer 6 and the lower temperature sensitive layer 9 are symmetrically arranged on the upper and lower sides of the intermediate layer substrate, and the upper temperature sensitive layer protective layer 5 and the lower temperature sensitive layer protective layer 10 are symmetrically arranged on the upper and lower sides of the intermediate layer substrate. In particular, the output resistance of the temperature sensing part is linearly related to the temperature and shows a positive growth trend, that is, the higher the temperature, the greater the output resistance value. However, it should be noted that due to the flexible substrate, the measured temperature cannot be too high (generally not more than 300°C), otherwise the sensor substrate will be damaged. In the actual implementation process, the actual temperature value can be obtained by detecting the resistance at both ends of the temperature sensing part and then inverting the temperature based on the relationship between the sensor resistance and temperature.

[0047] Figure 6 This is a schematic diagram of the anti-interference implementation principle of the temperature sensor of the present invention; Figure 6 As shown, a single temperature-sensitive layer's resistance decreases when subjected to compression and increases when subjected to tension. To address this issue, this application proposes a "bilaterally symmetrical" temperature-sensitive structure. In this structure, the upper temperature-sensitive layer 6 and the lower temperature-sensitive layer 9 are connected in series, achieving complementary resistance under interference such as bending and torsion, thereby improving the temperature sensor's anti-interference capability.

[0048] Optionally, the upper temperature sensitive layer 6 and the lower temperature sensitive layer 9 are both made of silver (Ag), platinum (Pt) or carbon nanotubes (CNT) or other materials with good electrical conductivity and temperature sensitivity.

[0049] Optionally, the upper temperature-sensitive layer protective layer 5 and the lower temperature-sensitive layer protective layer 10 may be made of non-metallic materials such as silicon dioxide (SiO2), boron nitride (BN), boron oxide (B2O3), and aluminum oxide (Al2O3). These materials must possess high melting points, high mechanical strength, corrosion resistance, good electrical insulation, chemical stability, and thermal stability to protect the temperature-sensitive layers 6 and 9 from interference from harsh external working environments and improve their anti-interference capabilities.

[0050] The upper temperature-sensitive layer 6 and the lower temperature-sensitive layer 9 are not independently provided, but are connected in series via wires provided on the temperature sensing electrode layer. This is intended to improve the temperature sensor's ability to resist interference, primarily bending interference. A single temperature-sensitive layer is very sensitive to bending interference and behaves in a very regular manner: its resistance increases when it is stretched and decreases when it is compressed. Connecting the upper temperature-sensitive layer 6 and the lower temperature-sensitive layer 9 in series ensures that when the upper substrate 1 and the lower substrate 11 are bent, one of the two temperature-sensitive layers is always compressed and the other is always stretched. Furthermore, since the two layers are positioned perfectly and experience the same degree of stretching and compression, their overall resistance remains virtually unchanged when connected in series. This makes the temperature-sensitive layer insensitive to bending interference and improves its ability to resist interference.

[0051] The temperature sensitive layers 6 and 9 and the temperature sensitive layer protection layers 5 and 10 are all prepared by magnetron sputtering; the temperature sensitive layer protection layers 5 and 10 are slightly larger than the temperature sensitive layers 6 and 9 and completely cover them.

[0052] Figure 7 The figure is a schematic diagram of the sensor application described in the present invention. This sensor can be used to detect the expansion force of single-cell or module batteries, such as soft-pack batteries and lithium-ion power batteries. To measure the expansion force of a module, the sensor can be placed directly between two batteries and clamped securely. However, it should be noted that the sensor pins need to be left exposed to facilitate lead testing. To measure the expansion force of a single battery cell, the sensor can be placed directly on one side of the cell. After securing the sensor, the cell needs to be clamped securely before conducting lead testing.

[0053] The above is only a preferred specific implementation method of the present invention, but the design concept of the present invention is not limited to this. Any technician familiar with the technical field who uses this concept to make non-substantial changes to the present invention within the technical scope disclosed by the present invention shall be deemed to infringe the protection scope of the present invention.

Claims

1. A flexible temperature-pressure dual-mode sensor for detecting battery expansion force, characterized in that: It includes an upper substrate, a pressure sensitive layer, an upper temperature sensitive layer, an electrode layer, an intermediate substrate, a lower temperature sensitive layer and a lower substrate arranged in order from top to bottom; the electrode layer includes a pressure sensing electrode layer and a temperature sensing electrode layer; a pressure spacer layer connecting the upper substrate and the middle substrate to form a certain space between the upper substrate and the middle substrate, wherein the pressure sensitive layer and the pressure sensing electrode layer are arranged in the space, the pressure sensitive layer is arranged on the upper substrate, the pressure sensing electrode layer is arranged on the middle substrate, and the pressure sensitive layer is spaced apart from the pressure sensing electrode layer; The upper temperature sensitive layer and the lower temperature sensitive layer have the same structure and are symmetrically arranged on the upper and lower sides of the intermediate layer substrate. The upper temperature sensitive layer and the lower temperature sensitive layer are connected in series through the temperature sensing electrode layer.

2. The flexible temperature-pressure dual-mode sensor for detecting battery expansion force according to claim 1, characterized in that: The upper substrate includes an upper hollow hole corresponding to the shape and position of the upper temperature-sensitive layer; the lower substrate includes a lower hollow hole corresponding to the shape and position of the lower temperature-sensitive layer.

3. The flexible temperature-pressure dual-mode sensor for detecting battery expansion force according to claim 1, characterized in that: The upper temperature-sensitive layer protective layer is arranged on the upper side of the intermediate layer substrate and completely covers the upper temperature-sensitive layer, and the lower temperature-sensitive layer protective layer is arranged on the lower side of the intermediate layer substrate and completely covers the lower temperature-sensitive layer.

4. The flexible temperature-pressure dual-mode sensor for detecting battery expansion force according to claim 3, characterized in that: The area of ​​the upper temperature-sensitive layer protective layer is larger than that of the upper temperature-sensitive layer; the area of ​​the lower temperature-sensitive layer protective layer is larger than that of the lower temperature-sensitive layer.

5. The flexible temperature-pressure dual-mode sensor for detecting battery expansion force according to claim 1, characterized in that: The upper temperature-sensitive layer, the lower temperature-sensitive layer, the upper temperature-sensitive layer protective layer and the lower temperature-sensitive layer protective layer are all made by magnetron sputtering.

6. The flexible temperature-pressure dual-mode sensor for detecting battery expansion force according to claim 1, characterized in that: The upper temperature sensitive layer is disposed radially outside the pressure sensitive layer.

7. The flexible temperature-pressure dual-mode sensor for detecting battery expansion force according to claim 1, characterized in that: The invention also includes an upper adhesive layer, wherein the upper adhesive layer is adhesively connected to the upper substrate and the middle substrate.

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