Flexible hydrogen sensor and manufacturing method thereof

Abstract

The invention discloses a flexible hydrogen sensor and a manufacturing method thereof, and the flexible hydrogen sensor comprises a flexible substrate which is made of a polyimide material; the gas sensitive layer is printed on the flexible substrate, and the gas sensitive layer is a graphene layer loaded with palladium nanoparticles and silver nanoparticles; the electrode layer is deposited on the gas sensitive layer; and the protective layer is formed on one side, deviating from the flexible substrate, of the electrode layer and the gas sensitive layer. The flexible hydrogen sensor can be flexibly installed in a new energy power battery pack, and hydrogen generated when the battery fails is sensitively detected.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sensors, and in particular to a flexible hydrogen sensor and a manufacturing method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, the safety and reliability of new energy power batteries have attracted much attention. During the use of lithium-ion batteries, battery thermal runaway may occur due to various internal or external factors. In the early stages of battery thermal runaway, a variety of gases including hydrogen will be produced. Timely and accurate detection of hydrogen production is crucial to preventing battery thermal runaway, avoiding fires and even explosions and other serious accidents.

[0003] At present, there are various sensor technologies for detecting hydrogen, but they face many challenges when applied to new energy power battery packs. Traditional hydrogen sensors often adopt rigid structures, which are difficult to adapt to the complex space and shape requirements inside the battery pack and cannot be flexibly installed; moreover, these sensors usually have problems such as insufficient sensitivity, slow response speed, high operating temperature and high power consumption, which are difficult to meet the needs of real-time monitoring and early warning of new energy power batteries.

[0004] In addition, the gas-sensitive materials used in existing sensors need to be improved in terms of selectivity and stability. They are easily interfered by other gases, resulting in inaccurate detection results. In addition, the manufacturing process is often complex and costly, which is not conducive to large-scale production and practical application.

[0005] Therefore, developing a hydrogen gas sensor that can be flexibly installed, has high sensitivity and fast response characteristics, low power consumption and is easy to manufacture is of great significance to ensure the safe operation of new energy power batteries. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a flexible hydrogen sensor and a manufacturing method thereof, which can be flexibly installed in a new energy power battery pack and sensitively detect the hydrogen generated when the battery fails.

[0007] In order to achieve the above object, the present invention provides a flexible hydrogen sensor in a first aspect, which comprises:

[0008] A flexible substrate, wherein the flexible substrate is made of a polyimide material;

[0009] A gas-sensitive layer, wherein the gas-sensitive layer is printed on the flexible substrate, and the gas-sensitive layer is a graphene layer loaded with palladium nanoparticles and silver nanoparticles;

[0010] an electrode layer, wherein the electrode layer is deposited on the gas-sensitive layer;

[0011] A protective layer is formed on a side of the electrode layer and the gas-sensitive layer that is away from the flexible substrate.

[0012] A flexible hydrogen sensor according to the present invention selects PI with high flexibility and chemical stability as a substrate, thereby ensuring the reliability of the sensor in complex environments, being adaptable to complex shapes and spaces inside a battery pack, and being easy to install; the gas-sensitive layer uses graphene-loaded palladium nanoparticles and silver nanoparticles, thereby improving the detection performance of hydrogen, being able to detect extremely low concentrations of hydrogen, having high sensitivity and rapid response performance, achieving accurate early warning of battery failure, responding to changes in hydrogen concentration in a short time, and improving the real-time monitoring; and the substrate and protective layer materials can reduce the impact of the battery system on the sensor, thereby ensuring the normal operation of the sensor.

[0013] Optionally, the protective layer is a polyimide layer or a silicon dioxide layer.

[0014] Optionally, the gas-sensitive layer further includes an organic resin, and the organic resin is mixed with graphene loaded with palladium nanoparticles and silver nanoparticles to form a printable gas-sensitive ink.

[0015] Further, the preparation of the gas sensitive ink includes:

[0016] Depositing graphene thin films on copper substrates using chemical vapor deposition;

[0017] Pd nanoparticles and silver nanoparticles were loaded onto graphene using co-reduction;

[0018] The graphene loaded with palladium nanoparticles and silver nanoparticles is mixed with an organic resin to obtain the gas-sensitive ink.

[0019] Furthermore, the gas-sensitive ink is printed on the flexible substrate by inkjet printing or screen printing to form the gas-sensitive layer.

[0020] Optionally, the electrode layer is deposited on the gas sensitive layer by vacuum evaporation, magnetron sputtering or electron beam evaporation.

[0021] In a second aspect, the present invention provides a method for manufacturing the above-mentioned flexible hydrogen sensor, which comprises the following steps:

[0022] S1. providing a flexible substrate made of polyimide;

[0023] S2, printing a gas-sensitive ink on one side of the flexible substrate to form a gas-sensitive layer, wherein the gas-sensitive layer is a graphene layer loaded with palladium nanoparticles and silver nanoparticles;

[0024] S3, depositing an electrode layer on a side of the gas-sensitive layer away from the flexible substrate;

[0025] S4. Coating a protective layer on the side of the electrode layer and the gas-sensitive layer facing away from the flexible substrate by spin coating or spray coating, and performing high-temperature curing.

[0026] According to the manufacturing method of the present invention, a highly flexible hydrogen sensor is made through simple steps, and advanced printed electronic technology and precise deposition methods are used to achieve efficient manufacturing and performance consistency of the sensor, which is conducive to large-scale production and promotion and application; the prepared sensor can be flexibly installed in a new energy power battery pack and sensitively detect the hydrogen generated when the battery fails.

[0027] Optionally, in step S2, the preparation of the gas sensitive ink includes:

[0028] Depositing graphene thin films on copper substrates using chemical vapor deposition;

[0029] Pd nanoparticles and silver nanoparticles were loaded onto graphene using co-reduction;

[0030] The graphene loaded with palladium nanoparticles and silver nanoparticles is mixed with an organic resin to obtain the gas-sensitive ink.

[0031] Further, the step of loading palladium nanoparticles and silver nanoparticles onto graphene by co-reduction includes:

[0032] Dispersing the graphene film in ultrapure water, and exfoliating the graphene oxide by ultrasonication to obtain a graphene oxide suspension;

[0033] dissolving palladium salts and silver salts in a solvent to form a mixed metal salt solution;

[0034] The mixed metal salt solution is mixed with the graphene oxide suspension, and urea is used as a reducing agent, and ethylene glycol is used to assist in the co-reduction to obtain graphene loaded with palladium nanoparticles and silver nanoparticles.

[0035] Further, the step of mixing the graphene loaded with palladium nanoparticles and silver nanoparticles with the organic resin comprises:

[0036] The graphene loaded with palladium nanoparticles and silver nanoparticles was mixed with the organic resin in a mass ratio of 3:1, a dispersant was added, and the mixture was stirred for 2 hours to obtain the gas-sensitive ink.

[0037] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic structural diagram of a flexible hydrogen sensor according to an embodiment of the present invention;

[0039] Figure 2 is an exploded schematic diagram of a flexible hydrogen sensor according to an embodiment of the present invention;

[0040] Figure 3 4 is a schematic diagram of the process of a flexible hydrogen sensor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0042] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0043] The materials of the present invention are all commercially available and used without further purification. All solvents used were of analytical grade.

[0044] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0045] Figure 1 FIG. 1 is a schematic diagram of a partial structure of a flexible hydrogen sensor provided by an embodiment of the present invention. Figure 1 and Figure 2 As shown, the flexible hydrogen sensor of this embodiment includes a flexible substrate 10, a gas-sensitive layer 20, an electrode layer 30 and a protective layer 40, wherein the flexible substrate 10 is made of a polyimide material; the gas-sensitive layer 20 is printed on the flexible substrate 10, and the gas-sensitive layer 20 is a graphene layer loaded with palladium nanoparticles and silver nanoparticles; the electrode layer 30 is deposited on the gas-sensitive layer 20; and the protective layer 40 is formed on the side of the electrode layer 30 and the gas-sensitive layer 20 away from the flexible substrate 10.

[0046] That is to say, the hydrogen sensor is supported by a flexible PI substrate, on which are sequentially a gas-sensitive layer 20, an electrode layer 30 and a protective layer 40 synthesized from graphene and palladium and silver nanometal particles; the flexible substrate 10 is made of PI material to provide flexible support for the entire sensor. The gas-sensitive layer 20 is a composite of graphene and palladium and silver nanometal particles, which has a porous microstructure and can accelerate the diffusion of gas in the sensing layer, and the components of the composite can adsorb gas molecules and promote the conductivity change of the sensing layer. The electrode is used to transmit electrical signals, and the protective layer is used to protect the internal structure of the sensor and improve the stability and service life of the sensor. This layered structure makes the functions of each part clear and works in coordination to ensure the performance and stability of the sensor. When the sensor is used for hydrogen detection, the conductivity of graphene will change after the graphene adsorbs the target gas. By determining the relationship between the conductivity change and the hydrogen concentration, the concentration of hydrogen can be measured by measuring the conductivity change of graphene.

[0047] Therefore, according to a flexible hydrogen sensor of an embodiment of the present invention, the sensor selects PI with high flexibility and chemical stability as a substrate, which ensures the reliability of the sensor in complex environments, can adapt to the complex shapes and spaces inside the battery pack, and is easy to install; the gas-sensitive layer 20 uses graphene-loaded palladium nanoparticles and silver nanoparticles to improve the detection performance of hydrogen, and can detect extremely low concentrations of hydrogen. It has high sensitivity and rapid response performance, realizes accurate early warning of battery failure, responds to changes in hydrogen concentration in a short time, improves the real-time monitoring, and the substrate and protective layer materials can reduce the impact of the battery system on the sensor, ensuring the normal operation of the sensor.

[0048] In some specific embodiments, the gas-sensitive layer 20 further includes an organic resin, which is mixed with graphene loaded with palladium nanoparticles and silver nanoparticles to form a printable gas-sensitive ink. In this way, the gas-sensitive ink can be accurately printed on the flexible substrate 10 using advanced printing technology to ensure the thickness and uniformity of the gas-sensitive layer 20. The shape of the gas-sensitive layer 20 can be designed according to requirements, for example Figure 2 In the process, a gas sensitive layer 20 with a thickness of about 60 microns is printed.

[0049] More specifically, the gas-sensitive ink is printed on the flexible substrate 10 by inkjet printing or screen printing to form the gas-sensitive layer 20. The inkjet printing or screen printing adopts the existing printing technology, which will not be described in detail here.

[0050] In some specific embodiments, the protective layer 40 is a polyimide layer or a silicon dioxide layer. Using a polyimide layer or a silicon dioxide layer that is resistant to chemical corrosion and high temperature can enhance the stability and durability of the sensor, reduce the impact of the battery system on the sensor, and ensure the normal operation of the sensor.

[0051] In some specific embodiments, the electrode layer 30 may be made of a metal material with good conductivity, such as gold, silver, etc. More specifically, the electrode layer 30 may be a gold interdigital electrode, and the electrode layer 30 is used to input a measurement voltage and measure changes in an output current.

[0052] Figure 3 FIG. 1 is a flow chart of a method for manufacturing a flexible hydrogen sensor according to an embodiment of the present invention. Figure 3 As shown, the method comprises the following steps:

[0053] S1. providing a flexible substrate made of polyimide;

[0054] S2, printing a gas-sensitive ink on one side of the flexible substrate to form a gas-sensitive layer, wherein the gas-sensitive layer is a graphene layer loaded with palladium nanoparticles and silver nanoparticles;

[0055] S3, depositing an electrode layer on a side of the gas-sensitive layer away from the flexible substrate;

[0056] S4. Coating a protective layer on the side of the electrode layer and the gas-sensitive layer facing away from the flexible substrate by spin coating or spray coating, and performing high-temperature curing.

[0057] It can be seen that in this embodiment, a highly flexible hydrogen sensor is made through simple steps, and advanced printed electronics technology and precise deposition methods are used to achieve efficient manufacturing and performance consistency of the sensor, which is conducive to large-scale production and popularization and application; the prepared sensor can be flexibly installed in a new energy power battery pack and sensitively detect the hydrogen generated when the battery fails.

[0058] In some specific embodiments, in step S1, a PI substrate of suitable thickness and size is selected and subjected to strict cleaning treatment to remove pollutants and impurities on the surface.

[0059] In some specific embodiments, step S2, preparing the gas sensitive ink includes the following sub-steps:

[0060] Depositing graphene thin films on copper substrates using chemical vapor deposition;

[0061] Pd nanoparticles and silver nanoparticles were loaded onto graphene using co-reduction;

[0062] The graphene loaded with palladium nanoparticles and silver nanoparticles is mixed with an organic resin to obtain the gas-sensitive ink.

[0063] In this way, palladium nanoparticles and silver nanoparticles can be loaded on graphene by a simple co-reduction method to improve the sensitivity of the gas-sensitive layer 20 to hydrogen detection.

[0064] More specifically, the steps of loading palladium nanoparticles and silver nanoparticles onto graphene by co-reduction include:

[0065] Dispersing the graphene film in ultrapure water, and exfoliating the graphene oxide by ultrasonication to obtain a graphene oxide suspension;

[0066] dissolving palladium salts and silver salts in a solvent to form a mixed metal salt solution;

[0067] The mixed metal salt solution is mixed with the graphene oxide suspension, and urea is used as a reducing agent, and ethylene glycol is used to assist in the co-reduction to obtain graphene loaded with palladium nanoparticles and silver nanoparticles.

[0068] More specifically, the step of mixing the graphene loaded with palladium nanoparticles and silver nanoparticles with the organic resin comprises:

[0069] The graphene loaded with palladium nanoparticles and silver nanoparticles was mixed with the organic resin in a mass ratio of 3:1, a dispersant was added, and the mixture was stirred for 2 hours to obtain the gas-sensitive ink.

[0070] In the embodiment, the method for manufacturing the flexible hydrogen sensor may specifically include the following steps:

[0071] First, a flexible PI substrate with a thickness of 80 microns is selected, ultrasonically cleaned with acetone and deionized water for 15 minutes, and dried at 80° C. to perform step S1 to provide a flexible substrate 10 made of polyimide.

[0072] Next, a graphene film was deposited on a copper substrate using chemical vapor deposition, and palladium nanoparticles and silver nanoparticles were loaded onto the graphene using co-reduction. The resulting composite material was mixed with an organic resin at a mass ratio of 3:1, and an appropriate amount of dispersant was added and stirred for 2 hours to prepare a gas-sensitive ink.

[0073] Specifically, a copper film is selected as a catalyst and substrate for graphene growth; the substrate material is placed in a CVD device, such as a tube furnace or a radio frequency chemical vapor deposition device; methane CH is introduced under a high temperature and high vacuum environment. 4As a carbon source, hydrogen is used as a reducing gas at the same time; the transition metal film is dissociated by a gas phase dissociation method, so that graphene sheets are gradually formed on the surface of the transition metal film; after a certain period of growth, the reaction gas is turned off, the substrate is cooled, and the graphene film is taken out. The chemical vapor deposition method adopts existing technology, and its specific operation is not described in detail. Then, the graphene film is dispersed in ultrapure water, and ultrasonicated for 1 hour to peel off the graphene oxide to obtain a graphene oxide suspension; then, palladium chloride and silver nitrate are dissolved to form a mixed metal salt solution; the graphene oxide suspension is then mixed with the mixed metal salt solution, and urea is used as a reducing agent. With the assistance of ethylene glycol, palladium and silver ions are simultaneously reduced to metal nanoparticles and loaded on graphene, and then the prepared graphene loaded with palladium nanoparticles and silver nanoparticles is washed, centrifuged, dried and other post-processing steps. The co-reduction method adopts existing technology, and its specific operation is not described in detail. Finally, the graphene loaded with palladium nanoparticles and silver nanoparticles is mixed with an organic resin in a mass ratio of 3:1, and ethanol is added as a dispersant, and stirred in a stirrer for 2 hours to obtain a gas-sensitive ink; after the gas-sensitive ink is prepared, the ink is printed on a flexible substrate 10 using screen printing technology at a printing speed of 10 mm / s to form a gas-sensitive layer 20 with a thickness of about 60 μm to perform step S2.

[0074] Subsequently, a gold electrode layer 30 with a width of 100 micrometers and a pitch of 200 micrometers is deposited on the gas sensing layer 20 by vacuum evaporation to perform step S3.

[0075] Finally, a polyimide protective layer with a thickness of 15 μm was coated by spin coating and cured at 150° C. for 2 hours to perform step S4 .

[0076] Thus, the flexible hydrogen sensor of this embodiment is manufactured.

[0077] Performance Test:

[0078] The flexible hydrogen sensor of the above embodiment was placed in an environment with a hydrogen concentration ranging from 0.05% to 2% and tested at 25°C.

[0079] The resistance change of the flexible hydrogen sensor was measured using a high-precision resistance meter. The results showed that the flexible hydrogen sensor had an obvious response when the hydrogen concentration was 0.05%, the response time was about 2 seconds, the recovery time was about 5 seconds, and the resistance change had a good linear relationship with the hydrogen concentration.

[0080] Application in power battery pack:

[0081] In the new energy power battery pack, a flexible hydrogen sensor of this embodiment is installed every 10 cm between the battery cells and fixed with high temperature resistant glue.

[0082] The flexible hydrogen sensor is connected to the battery management system via a wire, and the data transmission frequency is once per second.

[0083] When the battery experiences thermal runaway and the hydrogen concentration reaches 0.1%, the flexible hydrogen sensor quickly detects it and transmits the signal to the system, which then issues an alarm and takes corresponding measures.

[0084] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0085] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A flexible hydrogen sensor, characterized in that: include: A flexible substrate, wherein the flexible substrate is made of a polyimide material; A gas-sensitive layer, wherein the gas-sensitive layer is printed on the flexible substrate, and the gas-sensitive layer is a graphene layer loaded with palladium nanoparticles and silver nanoparticles; an electrode layer, wherein the electrode layer is deposited on the gas-sensitive layer; A protective layer is formed on a side of the electrode layer and the gas-sensitive layer that is away from the flexible substrate.

2. The flexible hydrogen sensor according to claim 1, characterized in that: The protective layer is a polyimide layer or a silicon dioxide layer.

3. The flexible hydrogen sensor according to claim 1, characterized in that: The gas-sensitive layer further comprises an organic resin, which is mixed with graphene loaded with palladium nanoparticles and silver nanoparticles to form a printable gas-sensitive ink.

4. The flexible hydrogen sensor according to claim 3, characterized in that: The preparation of the gas sensitive ink comprises: Depositing graphene thin films on copper substrates using chemical vapor deposition; Pd nanoparticles and silver nanoparticles were loaded onto graphene using co-reduction; The graphene loaded with palladium nanoparticles and silver nanoparticles is mixed with an organic resin to obtain the gas-sensitive ink.

5. The flexible hydrogen sensor according to claim 3, characterized in that: The gas-sensitive ink is printed on the flexible substrate by inkjet printing or screen printing to form the gas-sensitive layer.

6. The flexible hydrogen sensor according to claim 1, characterized in that: The electrode layer is deposited on the gas sensitive layer by vacuum evaporation, magnetron sputtering or electron beam evaporation.

7. The method for manufacturing a flexible hydrogen sensor according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. providing a flexible substrate made of polyimide; S2, printing a gas-sensitive ink on one side of the flexible substrate to form a gas-sensitive layer, wherein the gas-sensitive layer is a graphene layer loaded with palladium nanoparticles and silver nanoparticles; S3, depositing an electrode layer on a side of the gas-sensitive layer away from the flexible substrate; S4. Coating a protective layer on the side of the electrode layer and the gas-sensitive layer facing away from the flexible substrate by spin coating or spray coating, and performing high-temperature curing.

8. The method according to claim 7, characterized in that: In step S2, the preparation of the gas sensitive ink includes: Depositing graphene thin films on copper substrates using chemical vapor deposition; Pd nanoparticles and silver nanoparticles were loaded onto graphene using co-reduction; The graphene loaded with palladium nanoparticles and silver nanoparticles is mixed with an organic resin to obtain the gas-sensitive ink.

9. The method of claim 8, wherein: The steps of loading palladium nanoparticles and silver nanoparticles onto graphene by co-reduction include: Dispersing the graphene film in ultrapure water, and exfoliating the graphene oxide by ultrasonication to obtain a graphene oxide suspension; dissolving palladium salts and silver salts in a solvent to form a mixed metal salt solution; The mixed metal salt solution is mixed with the graphene oxide suspension, and urea is used as a reducing agent, and ethylene glycol is used to assist in the co-reduction to obtain graphene loaded with palladium nanoparticles and silver nanoparticles.

10. The manufacturing method according to claim 9, characterized in that: The step of mixing the graphene loaded with palladium nanoparticles and silver nanoparticles with the organic resin comprises: The graphene loaded with palladium nanoparticles and silver nanoparticles was mixed with the organic resin in a mass ratio of 3:1, a dispersant was added, and the mixture was stirred for 2 hours to obtain the gas-sensitive ink.

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