阅读说明：本技术 一种电阻式温度传感器及其制备方法和用途 (Resistance type temperature sensor and preparation method and application thereof ) 是由 谢琎 赵连企 于 2021-06-22 设计创作，主要内容包括：本发明提供一种电阻式温度传感器及其制备方法和用途。本发明提供一种柔性电极,所述柔性电极包括电极和电极基底,所述电极设于所述电极基底上,且具有微纳结构。本发明中申请人构建了一种微纳结构的电阻式温度传感器,用于原位测量电池局部温度及整体温度,具有灵敏度高、由于测量温度为电池电芯各处的温度,能够很好的对电池整体热稳定性进行评估。(The invention provides a resistance-type temperature sensor and a preparation method and application thereof. The invention provides a flexible electrode which comprises an electrode and an electrode substrate, wherein the electrode is arranged on the electrode substrate and has a micro-nano structure. The invention discloses a resistance type temperature sensor with a micro-nano structure, which is used for measuring the local temperature and the overall temperature of a battery in situ, has high sensitivity, and can well evaluate the thermal stability of the whole battery because the measured temperature is the temperature of each part of the battery core.)

1. A flexible electrode, comprising an electrode and an electrode substrate; the electrode is arranged on the electrode substrate and has a micro-nano structure.

2. The flexible electrode of claim 1, wherein the electrode substrate is a polyimide substrate.

3. The flexible electrode according to claim 1, wherein the electrode is a metal material, and the resistivity of the metal material linearly changes within 0-500 ℃.

4. The flexible electrode according to claim 1, wherein the size of the micro-nano structured electrode is not more than 100 μm.

5. The flexible electrode of claim 1, wherein the electrode base layer has a thickness of no more than 20 μ ι η.

6. A preparation method of the flexible electrode according to any one of claims 1 to 5, wherein a micro-nano processing technology is adopted, a micro-nano structure is engraved on photoresist through exposure and development, and then an electrode with the micro-nano structure is formed through a metal deposition process; and finally forming an electrode substrate for bearing the electrode.

7. A resistance-type temperature sensor is characterized by comprising the flexible electrode, a connecting lead and a display instrument.

8. The resistive temperature sensor of claim 7, wherein the resistance of the resistance temperature detector is 150-300 Ω.

9. Use of a resistive temperature sensor according to claim 7 or 8 for testing the temperature of a battery.

10. A battery, characterized in that, a plurality of the resistance temperature sensors of claim 7 or 8 are provided on the battery cell.

Technical Field

The invention relates to the field of energy devices, in particular to a resistance type temperature detector and a preparation method and application thereof.

Background

Safety is very important for lithium batteries, wherein thermal runaway caused by internal short circuits of the batteries is the most common, and on one hand, the internal short circuits of the batteries can cause local temperature rise, and on the other hand, the temperature rise can cause further thermal failure of the batteries, so that the detection of the internal temperature of the batteries is very important.

In the initial stage of thermal runaway of a battery, the short-circuit area inside the battery is extremely small, the influence on the whole body temperature is limited, and the detection cannot be carried out through a traditional macroscopic temperature sensor.

How to effectively detect the local temperature change of the battery in real time and how to evaluate the overall thermal stability of the battery is the key for solving the problem.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide a resistance temperature sensor, a preparation method and a use thereof, which are used for solving the problems that the safety of a battery cannot be effectively monitored and the evaluation of the overall thermal stability of the battery lacks an effective and accurate method in the prior art.

To achieve the above objects and other related objects, the present invention is achieved by the following technical solutions.

The invention provides a flexible electrode, which comprises an electrode and an electrode substrate; the electrode is arranged on the electrode substrate and is provided with a micro-nano structure.

Preferably, the electrode substrate is a polyimide substrate. The polyimide polymer is used as a substrate material and has the advantages of good thermal stability, bending resistance, high temperature resistance, light weight, thinness and the like. The polyimide material also has electrolyte resistance effect when used for testing the temperature of the lithium battery in the present application.

Preferably, the electrode is a metal material, and the resistivity of the metal material linearly changes within 0-500 ℃.

Preferably, the size of the micro-nano structured electrode is not more than 100 μm. Preferably not more than 50 μm. The smaller the electrode size, the higher the spatial resolution which can be provided by the temperature sensor during measurement, and the smaller the electrode size, the higher the requirement on the photoetching process, the 3 μm line width is selected to control the size of the sensor electrode within 50 μm, so that the higher detection precision can be ensured, and the process processing is convenient.

Preferably, the electrode base layer has a thickness of not more than 20 μm.

The invention also provides a preparation method of the flexible electrode, which comprises the steps of adopting a micro-nano processing technology, etching a micro-nano structure on the photoresist by exposure and development, and then forming the electrode with the micro-nano structure by a metal deposition process; and finally forming an electrode substrate for bearing the electrode.

The invention provides a resistance-type temperature sensor which comprises the flexible electrode, a connecting wire and a display instrument. The flexible electrode, the connecting lead and the display instrument form an electric loop.

The main principle of the resistance temperature sensor is as follows: the resistance of the sensor changes with changes in temperature. More preferably, the metal material is one or more selected from gold, silver, platinum, copper and nickel. More preferably, the metal material is one selected from gold, silver, platinum, copper and nickel. Most preferably, the metal material is gold or platinum.

Preferably, the resistance of the resistance temperature detector is 150-300 omega. If the resistance is large, high driving voltage of the resistance temperature detector is needed, and the high driving voltage of the resistance temperature detector may generate crosstalk with a battery circuit; if the resistance of the resistance temperature detector is too small, the rest part of the amplifying circuit is interfered, and the temperature detection precision is influenced.

The invention also discloses the application of the resistance temperature sensor for testing the temperature of the battery.

The invention also provides a battery, wherein a plurality of resistance type temperature sensors are arranged on the battery cell. Such as on the outer surface of the positive current collector, the outer surface of the negative current collector, or inside the cell outer package of a battery cell. The outer surface of the positive current collector and the outer surface of the negative current collector are surfaces which are not contacted with the electrolyte.

The technical scheme of the invention has the following beneficial effects:

the invention discloses a resistance type temperature sensor with a micro-nano structure, which is used for measuring the local temperature and the overall temperature of a battery in situ, has high sensitivity, and can well evaluate the thermal stability of the whole battery because the measured temperature is the temperature of each part of the battery core.

Drawings

FIG. 1 shows a lithographic pattern in an embodiment of the invention.

FIG. 2 is a schematic view of a glass plate loaded with a resistance temperature sensor according to an embodiment.

FIG. 3 is a second schematic structural view of the glass plate loaded with the resistance temperature sensor in the embodiment.

Fig. 4 shows the copper cathode of the composite resistance temperature sensor in the example.

Fig. 5 shows the resistance R as a function of the temperature t in the example.

FIG. 6 is a schematic diagram of an embodiment of making a micro-hole at a corresponding electrode position.

Fig. 7 shows the packaged battery in the example.

FIG. 8 is a graph showing the temperature and voltage of the micro-region of the battery in accordance with the embodiment with time.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

Before the present embodiments are further described, it is to be understood that the scope of the invention is not limited to the particular embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.

When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, and materials used in the examples, any methods, devices, and materials similar or equivalent to those described in the examples may be used in the practice of the invention in addition to the specific methods, devices, and materials used in the examples, in keeping with the knowledge of one skilled in the art and with the description of the invention.

In the application, the applicant constructs a flexible electrode with a micro-nano structure, and then forms one or more resistance type temperature sensors which are arranged on a battery cell and used for measuring the local temperature and the overall temperature distribution condition of the battery in situ. The resistance-type temperature sensor formed by the technical scheme can effectively feed back one or more local temperature distribution conditions of the battery cell in real time, and has high sensitivity and high accuracy. By adopting the technical concept in the application, the temperature conditions of different materials in the battery or the temperature conditions of all positions of the same material can be compared under the condition of short circuit, so that the overall thermal stability of the battery is evaluated.

In particular, the present application provides a flexible electrode comprising an electrode and an electrode substrate; the electrode is arranged on the electrode substrate and has a micro-nano structure.

In a preferred embodiment, the electrode substrate is a polyimide substrate. The polyimide polymer is used as a substrate material and has the advantages of good thermal stability, bending resistance, high temperature resistance, light weight, thinness and the like. When the flexible electrode constructed in the application is used for forming the resistance type temperature sensor to test the temperature of the lithium battery, the polyimide material is arranged near the battery electric core, and the polyimide material also has a good electrolyte resistance effect. The flexible electrode substrate layer can be used as a protective layer to isolate a battery circuit and a resistance-type temperature sensor circuit, isolate electrolyte and the like; secondly, the flexible polymer substrate layer is easy to form, the thickness is very easy to control, and the influence on the accuracy and the effectiveness of temperature sensing caused by the excessively thick thickness of the electrode substrate layer is avoided; moreover, the flexible electrode substrate layer can be well attached and assembled on the surface of the battery cell, and has the characteristic of easy assembly, so that the resistance type temperature sensor can measure the temperature of the battery cell in real time.

The electrode is made of a metal material, and the resistivity of the metal material linearly changes within 0-500 ℃. The linear change trend in the temperature range can meet the requirement of thermal stability evaluation of the battery.

The electrode in the present application is an electrode with a micro-nano structure, and in a preferred embodiment, the size of the electrode with a micro-nano structure is not more than 100 μm. Preferably not more than 50 μm, such as 30 to 50 μm. The smaller the electrode size, the higher the spatial resolution which can be provided by the temperature sensor in measurement, and the smaller the electrode size has higher requirements on the photoetching process, and the sensor electrode size can be controlled within 50 μm by selecting the line width of 3 μm, so that the higher detection precision can be ensured, and the process processing is facilitated.

In a preferred embodiment, the electrode base layer has a thickness of not more than 20 μm. In a more preferred embodiment, the thickness of the electrode base layer is 1 to 9 μm.

In the embodiment of the invention, the preparation method of the flexible electrode is further specifically provided, the micro-nano structure is engraved on the photoresist by exposure and development by adopting a micro-nano processing technology, and then the electrode with the micro-nano structure is formed by a metal deposition process; and finally forming an electrode substrate for bearing the electrode. The micro-nano processing technology can refer to the technology and means in the field of semiconductors. In a preferred embodiment, the process of depositing metal may be magnetron sputter deposition. In a more preferred embodiment, to enhance the robustness of the electrode adhesion, some titanium or titanium alloy may be first deposited by magnetron sputtering.

The invention also provides a specific resistance-type temperature sensor which comprises the flexible electrode, a connecting lead and a display instrument. In the resistance-type temperature sensor, the flexible electrode is used for detecting real-time change of the temperature near the battery cell, and the resistance of the flexible electrode is increased along with the increase of the temperature of the accessory of the battery cell, so that the current or the voltage in the resistance-type temperature sensor is obviously changed and is reflected on a display instrument.

In this application, the main principle of the resistance temperature sensor is: the resistance of the electrodes in the sensor changes with changes in temperature. In a more preferred embodiment, the metal material is one or more selected from gold, silver, platinum, copper and nickel. In a more preferred embodiment, the metal material is one selected from gold, silver, platinum, copper and nickel. In a most preferred embodiment, the metal material is gold or platinum, and the dominant dependence of the resistance of the electrode formed from these two metals on temperature is most pronounced.

In consideration of practical application, in a preferred embodiment, the resistance of the resistance temperature detector is 150-300 Ω. The resistance is obtained by testing under the conditions of normal temperature and normal pressure, and the resistance of the resistance temperature detector is basically determined by the flexible electrode. If the resistance is large, high driving voltage of the resistance temperature detector is needed, and the high driving voltage of the resistance temperature detector may generate crosstalk with a battery circuit; if the resistance of the resistance temperature detector is too small, the rest part of the amplifying circuit is interfered, and the temperature detection precision is influenced.

In the specific implementation mode of the invention, the application of the resistance temperature sensor for testing the temperature of the battery is also disclosed.

The invention also provides a specific battery, and a plurality of resistance type temperature sensors are arranged on the battery cell. Such as on the outer surface of the positive current collector of a battery cell, the outer surface of the negative current collector, or inside the cell overwrap. The outer surface of the positive current collector and the outer surface of the negative current collector are surfaces which are not contacted with the electrolyte.

In order to further explain the technical scheme and the technical effects achieved by the technical scheme, the applicant of the present application specifically provides the following embodiments and test effects.

In this embodiment, a specific method for manufacturing a battery with a resistance temperature sensor is provided as follows:

1. selecting a glass plate as a bearing layer, wherein the size of the glass plate is 50 x 50m, and the thickness of the glass plate is 1.5 mm; soaking in piranha (concentrated sulfuric acid: hydrogen peroxide: 9: 1 wt%) for 10min, cleaning with ultrapure water, and blow-drying to remove impurities and keep it clean.

2. Spin-coating photoresist on the surface of the cleaned glass plate: the spin coating step of the photoresist with the model AZ5214 comprises the following steps: spin coating at 600rpm for 10s and spin coating at 6000rpm for 1 min; then, the paste was dried at 110 ℃ for 90 seconds to a paste thickness of about 1 μm.

3. Photoetching a designed photoetching pattern by using a photoetching machine, wherein the pattern is shown in figure 1, and the light source intensity of the photoetching machine is 160mJ cm^-2And developing for 30 s. Transverse and longitudinal directions of photoetching patternThe width of the glass plate is 46mm and is slightly smaller than 50mm of the glass plate. The temperature sensor is essentially a section of S-shaped metal filament, and since the resistance value of the metal in the range of 0-30 ℃ is linearly increased along with the temperature change, the real-time temperature can be obtained by measuring the resistance value of the metal. The s-shaped filament on the right in fig. 1 is the body of the temperature sensor RTD, and the large area pattern on the left in fig. 1 provides only electrical connections for the RTD. The photoetching pattern is divided into two layers due to the difference of precision requirements, the dark gray layer is an RTD main body, the photoetching precision is 0.6 mu m, the light gray layer is only used as a lead of the RTD main body, and the photoetching precision is 5 mu m. Since high lithography accuracy requires more lithography time, the split-level lithography can effectively reduce the lithography time. A repeated area exists between the two layers, as noted on the right of FIG. 1, and the width is 120 μm and the length is 100 μm. The reason is that the two layers have different precisions, photoetching can be carried out in sequence according to the layers, certain offset can be caused between the patterns of the two layers in the process, and the repeated area can provide buffer for the offset, so that the connection of the two patterns is ensured. The two diametrically opposed S-shaped filaments in FIG. 1 are shown in the outline outlined by a dashed outline having a width of 3 μm, a transverse length of 45 μm, a spacing of 3 μm adjacent to each other and a total length of 315 μm. This is designed for two reasons, one is to minimize the size of the RTD to obtain the centermost temperature of the short circuit area; and secondly, the resistance of the core S-shaped lead of the RTD is controlled, too high resistance can cause the requirement of too high driving voltage and can interfere with a battery circuit, and too low resistance can cause the resistance of the RTD not to be concentrated in a central area, so that the measured resistance can be influenced by other circuit connecting parts, and the temperature measurement precision is reduced. The distance between the two S-shaped wires was 400 μm in order to obtain both a short-circuit point and a temperature at 400 μm distance. The width of the large-area light gray pattern in the left picture of fig. 1 is 4.5mm, the transverse distance between adjacent patterns is 0.5mm, and the longitudinal distance from top to bottom is 0.3mm, 0.5mm, 0.7mm, 0.5mm and 0.3mm in sequence. The reason is to design the RTD measurement region to be (0, 0) (10, 10) (10, -10) (-10, 10) (-10 ) units in mm with respect to the center position of the battery, respectively.

4. Reactive ion etching system (abbreviated as RIE) O₂Etching for 1min at 200w to remove incomplete residual photoresist, and etching the photoresist to a thickness of 100-120 nm.

5. And performing magnetron sputtering deposition on the photoetched pattern to obtain 10nm titanium and 50nm gold, and soaking the pattern overnight by using a reagent Remover PG.

6. And (4) carrying out proper ultrasonic treatment for about 10s to remove residual metal, washing with isopropanol for three times, washing with ultrapure water and drying. A glass plate carrying a resistance temperature sensor was obtained as shown in fig. 2 and 3.

7. A polyamic acid (abbreviated as PAA) solution was spin-coated on the glass surface. The PAA solution is viscous and this step should ensure that the PAA is spread evenly on the glass plate before starting the spin and avoid the formation of bubbles.

8. Immediately placing the glass plate coated with the PAA solution on a hot plate, drying for 30min at 70 ℃, and then converting the PAA into polyimide PI through dehydration crosslinking at 80-300 ℃, wherein the process is completed in a vacuum or anhydrous environment. The flexible electrode is formed so far.

9. Sequentially growing 10nm titanium and 100nm copper on the surface of the PI on the glass by magnetron sputtering; magnetron sputtering titanium was used to form the adhesion layer.

10. And removing the PI layer partially covered with the Cu by using a knife to expose connecting wire pins of the photoetching pattern and simultaneously avoid scratching metal gold below the PI.

11. And respectively welding 20 pins corresponding to the ten flexible electrodes of the photoetching pattern with a copper enameled wire. The copper cathode of the composite resistance temperature sensor is obtained, as shown in fig. 4.

12. The 10 temperature thermistors are subjected to temperature correction, the constant temperature box is respectively kept at 30 ℃, 50 ℃, 70 ℃ and 90 ℃ for 2h, the I-V curve of each resistor at the temperature is measured, the open-circuit voltage is from 0V → 50mV → 0mV, the sweep rate is 10mV/s, and the change curve of the resistor R along with the temperature t is drawn. As shown in fig. 5, R is 176.953+ T0.201 (0.1866) Ω, and the theoretical slope of the resistance of gold metal in parentheses with temperature changes substantially matches.

13. A 40 x 40mm separator was cut and circular holes of about 150 microns in diameter were made at their corresponding electrode locations and aligned with the electrodes and then secured as shown in fig. 6.

14. The copper surface is soldered to a wire at any corner of the selected glass plate.

15. Square battery diaphragm 40 x 40mm, positive electrode 30 x 30mm, 5 x 35mm glass plate were placed upwards in sequence.

16. The 20 lead wires connected to the RTD and the positive and negative electrodes of the battery were led out, and the battery was sealed with an aluminum plastic film, as shown in fig. 7.

17. In the operation process of the battery, a constant voltage of 40mV is applied to the RTD, the current value of the RTD is recorded, the resistance of the current RTD can be obtained, and the temperature change of the RTD, namely the temperature of the battery at the micro-region, can be obtained by means of a resistance-temperature curve.

18. Fig. 8 shows the temperature and voltage of battery micro-regions as a function of time for a pouch cell containing artificial localized temperature hot spots as measured by RTD. The short circuit area is No. 5 area, the star marks on the upper part of the short circuit area, the temperature of No. 5 RTD area is obviously higher than that of other areas, the temperature can reach up to 300 ℃, and the temperature of No. 6 RTD which is 400um away from the short circuit area is slightly increased. The temperature of the other zones was kept at 25 ℃ at all times, and the curves coincided with each other in the figure.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.