A gas sensor, battery pack, energy storage system and new energy vehicle

Abstract

This application provides a gas sensor, a battery pack, an energy storage system, and a new energy vehicle. The gas sensor includes a heating layer, an insulating layer, an electrode layer, and a gas-sensitive layer stacked sequentially. The gas-sensitive layer is made of tin-doped iron oxide, with at least a portion of the tin atomically doped into the iron oxide lattice. This allows for better dispersion of tin within the iron oxide lattice, resulting in more active sites. These active sites facilitate interaction between the gas-sensitive layer material and hydrogen molecules, improving the sensitivity of hydrogen detection and enabling better monitoring of hydrogen concentration. This, in turn, enhances the performance of the gas sensor and prevents thermal runaway.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a gas sensor, a battery pack, an energy storage system, and a new energy vehicle. Background Technology

[0002] Due to the complex operating conditions of battery packs, thermal runaway may occur in one of the secondary batteries. Once thermal runaway occurs, it releases a large amount of smoke and can further trigger thermal runaway in other secondary batteries, ultimately leading to a fire or explosion. However, before thermal runaway occurs, other gases, including electrolyte volatiles, hydrogen, and carbon monoxide, are released. Therefore, monitoring the hydrogen concentration within the battery pack can provide early warning and prevent thermal runaway from occurring. Summary of the Invention

[0003] This application provides a gas sensor, a battery pack, an energy storage system, and a new energy vehicle for detecting the hydrogen concentration in the battery pack, thereby monitoring the hydrogen concentration and preventing thermal runaway.

[0004] In a first aspect, embodiments of this application provide a gas sensor, which may include: a heating layer, an insulating layer, an electrode layer, and a gas-sensitive layer stacked sequentially. The gas-sensitive layer is made of tin-doped iron oxide, with at least a portion of the tin atomically doped into the iron oxide lattice. This allows for better dispersion of tin within the iron oxide lattice, thereby generating more active sites. These active sites facilitate interaction between the gas-sensitive layer material and hydrogen molecules, improving the sensitivity of hydrogen detection and enabling better monitoring of hydrogen concentration. This, in turn, enhances the performance of the gas sensor and prevents thermal runaway.

[0005] Optionally, in the atomic radius R space diagram of tin-doped iron oxide, a Sn-O-Fe characteristic peak is observed in the range of 2 to 3 Å. The R space diagram is formed by performing a Fourier transform on the absorption spectrum obtained after measuring the K-edge absorption spectrum of tin-doped iron oxide. The appearance of the Sn-O-Fe characteristic peak indicates that Sn is atomically bonded to the O atoms in O-Fe, meaning that Sn has entered the iron oxide lattice in atomic form. In tin-doped iron oxide, it is possible that all Sn has entered the iron oxide lattice in atomic form, or it may be that only a portion of Sn has entered the iron oxide lattice in atomic form. However, regardless of how many Sn atoms have entered the iron oxide lattice in atomic form, the Sn-O-Fe characteristic peak will appear in the R space diagram.

[0006] Furthermore, the intensity of the Sn-O-Fe characteristic peak in the R space diagram is greater than or equal to 2.0, which indicates that the Sn-O-Fe characteristic peak has a relatively large intensity. This suggests that the Sn-O-Fe characteristic peak is not a spurious peak caused by interference. In other words, when the intensity of the characteristic peak in the R range of 2 to 3 Å is greater than or equal to 2.0, the characteristic peak appearing in this range can be considered as the Sn-O-Fe characteristic peak, thus avoiding the influence of spurious peaks on the detection results.

[0007] Furthermore, in the R-space diagram, there is a Sn-O characteristic peak in the range of 1 to 2 Å. The Sn-O characteristic peak indicates that Sn atoms are bonded to O in iron oxide, and the corresponding substance may be tin oxide. This indicates that Sn atoms have captured O from iron oxide to form tin oxide, which is likely in a physically mixed state with iron oxide. Therefore, Sn is not doped into the lattice of iron oxide. The intensity ratio of the Sn-O characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 5.0, indicating that the intensity of the Sn-O-Fe characteristic peak is not low compared to the intensity of the Sn-O characteristic peak. From this perspective, if the intensity ratio of the Sn-O characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 5.0, it can also be considered that the characteristic peak appearing in the range of 2 to 3 Å is not a spurious peak but a Sn-O-Fe characteristic peak, thus avoiding the influence of spurious peaks on the detection results.

[0008] In the R-space diagram, a Sn-O-Sn characteristic peak is present in the range of 3.5 Å to 4 Å. This Sn-O-Sn characteristic peak indicates that multiple Sn atoms are bonded to O atoms. The corresponding substance may be aggregated tin oxide or tin oxide particles. Aggregated tin oxide or tin oxide particles are likely in a physically mixed state with iron oxide, so Sn atoms are not doped into the iron oxide lattice. The intensity ratio of the Sn-O-Sn characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 0.1, indicating that the Sn-O-Fe characteristic peak has a higher intensity than the Sn-O-Sn characteristic peak. From this perspective, if the intensity ratio of the Sn-O-Sn characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 0.1, the characteristic peak appearing in the range of 2 Å to 3 Å can also be considered not as a heterogeneous peak but as a Sn-O-Fe characteristic peak, thus avoiding the influence of heterogeneous peaks on the detection results.

[0009] Optionally, a heating layer provides heat to the gas-sensitive layer, an insulating layer isolates the heating layer from the electrode layer, and the electrode layer detects the resistance of the gas-sensitive layer. Thus, the heating layer heats the gas-sensitive material in the gas-sensitive layer to its operating temperature. When the gas-sensitive material at its operating temperature comes into contact with a gas such as hydrogen, if the gas concentration reaches a certain level, the resistance of the gas-sensitive layer will change. The electrode layer then detects this resistance, allowing the gas concentration to be determined based on the resistance value, thereby realizing the gas detection function of the gas sensor.

[0010] Optionally, the insulating layer has a planar structure. Alternatively, the insulating layer has a tubular structure, with the heating layer located on the inner wall of the tubular structure and the electrode layer and gas-sensitive layer located on the outer wall of the tubular structure. The gas sensor also includes heating terminals and electrode terminals, with the heating terminals connected to the heating layer and the electrode terminals connected to the test electrodes within the electrode layer. The heating terminals are located at both ends of the tubular structure, and the electrode terminals are wound around the outer wall of the tubular structure. Alternatively, the gas sensor can be a MEMS chip. This allows for various structural forms of the gas sensor, enabling the selection of the appropriate structure according to actual needs to meet the requirements of different application scenarios and broaden the application range.

[0011] Secondly, embodiments of this application also provide a battery pack, which may include: a housing, a secondary battery, and a gas sensor as described in the first aspect and any embodiment thereof, wherein the secondary battery and the gas sensor are disposed within the housing; the gas sensor is used to detect the hydrogen concentration within the housing. This improves the safety and reliability of the battery pack.

[0012] It should be understood that since the principle by which this battery pack solves the problem is similar to that of the aforementioned gas sensor, the implementation and technical effects of this battery pack can be found in the implementation and technical effects of the aforementioned gas sensor, and the repetition will not be repeated.

[0013] Thirdly, embodiments of this application also provide an energy storage system, which includes a battery pack and a power converter as described in the second aspect above. The power converter is used to convert AC power output from an external AC power source into DC power for output to the battery pack, and / or, the power converter is used to convert DC power output from the battery pack into AC power for output to a load or the power grid. Thus, while improving the safety and reliability of the battery pack, the safety and reliability of the energy storage system are also enhanced.

[0014] It should be understood that since the principle of this energy storage system in solving the problem is similar to that of the aforementioned battery pack, the implementation and technical effects of this energy storage system can be found in the implementation and technical effects of the aforementioned battery pack, and the repetition will not be repeated.

[0015] Fourthly, this application also provides a new energy vehicle, which includes a motor and a battery pack as described in the second aspect above, the battery pack being used to provide driving power to the motor. Thus, by improving the safety and reliability of the battery pack, the safety and reliability of the new energy vehicle are also improved.

[0016] It should be understood that since the principle by which this new energy vehicle solves the problem is similar to that of the aforementioned battery pack, the implementation and technical effects of this new energy vehicle can be found in the implementation and technical effects of the aforementioned battery pack, and the repetitions will not be repeated. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the energy storage system provided in the embodiments of this application;

[0018] Figure 2 This is a schematic diagram of the structure of a new energy vehicle provided in an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of the structure of a gas sensor with a planar sensing component, as provided in an embodiment of this application.

[0020] Figure 4 R-space diagrams provided for embodiments of this application;

[0021] Figure 5 This is a schematic diagram of another gas sensor provided in an embodiment of this application;

[0022] Figure 6 A schematic diagram of the structure of the sensing component provided in the embodiments of this application when it is a tubular structure;

[0023] Figure 7 A schematic diagram of the structure of a MEMS chip provided in the embodiments of this application;

[0024] Figure 8 Morphology diagram of tin-doped iron oxide provided in the embodiments of this application;

[0025] Figure 9 This is a schematic diagram of the structure of a battery pack provided in an embodiment of this application;

[0026] Figure 10 The embodiments and comparative examples provided for the purposes of this application show the response of different concentrations of hydrogen gas.

[0027] Explanation of reference numerals in the attached figures:

[0028] 10-Heating layer, 11-Heating terminal, 10a-Heating wire, 20-Insulating layer, 30-Electrode layer, 31-Electrode terminal, 30a-Wire, 40-Gas-sensitive layer, 51-Substrate, 61-Base, 62-Sensing component, 63-Support column, 64-Heating transmission component, 65-Electrode transmission component, 101-Box, 102-Secondary battery, 103-Gas sensor. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0030] It should be noted that the same reference numerals in the accompanying drawings of this application denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms expressing position and direction described in this application are illustrative based on the accompanying drawings, but may be modified as needed, and all such modifications are included within the scope of protection of this application. The accompanying drawings of this application are for illustrating relative positional relationships only and do not represent actual scale.

[0031] It should be noted that, in this application, the words "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplarily" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of words such as "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner. In the embodiments of this application, the words "first," "second," etc., do not limit the number or order.

[0032] To facilitate understanding of the technical solutions provided in the embodiments of this application, the application scenarios will be explained first below.

[0033] The technical solutions provided in this application can be widely applied in energy storage systems. These energy storage systems can be used, but are not limited to, in scenarios such as residential energy storage, site energy, smart photovoltaics, and data center energy, for storing electrical energy and providing it externally. See also... Figure 1 The diagram shows the architecture of an energy storage system. The energy storage system may include: a battery cluster and a power converter 200. The battery cluster includes multiple battery packs 100 connected in series. Figure 1 The diagram shows only one battery pack 100 as an example. The power converter 200 can convert the AC power output from an external AC power source (such as the power grid 300) into DC power and output it to the battery pack 100 in the battery cluster to charge the battery pack 100. It can also convert the DC power output from the battery pack 100 in the battery cluster into AC power and output it to the load 400 or the power grid 300 to discharge the battery pack 100.

[0034] Of course, the technical solutions provided in this application can also be applied to other scenarios besides energy storage systems, such as, but not limited to, new energy vehicles, such as... Figure 2 As shown, a new energy vehicle may include a battery pack and a motor. The battery pack can provide driving power to the motor, thereby driving the new energy vehicle.

[0035] For example, the battery pack 100 may include a housing and multiple secondary batteries, each housed within the housing. These secondary batteries can be connected in series, in parallel, or a combination of both to give the battery pack 100 a high capacity and high voltage, making it suitable for various applications. The secondary batteries may include, but are not limited to, lithium-ion, sodium-ion, or potassium-ion batteries. Due to the complex operating conditions of the battery pack, thermal runaway may occur in one of the secondary batteries. Once thermal runaway occurs, it releases a large amount of smoke, which can further trigger thermal runaway in other secondary batteries, ultimately leading to a fire or explosion. However, before thermal runaway occurs, other gases, including electrolyte vapors, hydrogen, and carbon monoxide, are released. Therefore, monitoring and early warning can be provided by detecting the hydrogen concentration within the battery pack, thus preventing thermal runaway.

[0036] Based on this, embodiments of this application provide a gas sensor that can be used to detect the hydrogen concentration within a battery pack, thereby monitoring the hydrogen concentration and preventing thermal runaway. For example, as... Figure 3 As shown, the gas sensor provided in this application embodiment includes: a heating layer 10, an insulating layer 20, an electrode layer 30, and a gas-sensitive layer 40 stacked sequentially. The insulating layer 20 is used to isolate the heating layer 10 and the electrode layer 30. When the heating layer 10 is made of a material with certain conductivity, such as ruthenium oxide, the presence of the insulating layer 20 can prevent the heating layer 10 from short-circuiting with the electrode layer 30, thereby preventing the gas sensor from malfunctioning. The heating layer 10 is used to provide heat to the gas-sensitive layer 40 so that the gas-sensitive material in the gas-sensitive layer 40 is heated to the working temperature. When the gas-sensitive material at the working temperature comes into contact with a gas, such as hydrogen, if the gas concentration reaches a certain level, the resistance value of the gas-sensitive layer 40 will change. The electrode layer 30 is used to detect the resistance value of the gas-sensitive layer 40, thereby determining the gas concentration based on the resistance value, and realizing the gas detection function of the gas sensor. The gas-sensitive layer 40 is made of tin-doped iron oxide, with at least a portion of the tin (element symbol Sn) being atomically doped into the iron oxide lattice. This allows for better dispersion of tin within the iron oxide lattice, resulting in more active sites. These active sites facilitate the interaction between the gas-sensitive layer 40 and hydrogen molecules, enhancing the sensitivity of hydrogen detection and enabling better monitoring of hydrogen concentration. This, in turn, improves the performance of the gas sensor and prevents thermal runaway.

[0037] It should be understood that the gas sensor provided in this application embodiment is not limited to use in battery packs, nor is it limited to detecting hydrogen. The gas sensor can also be applied to other scenarios and detect other gases, and no specific limitations are made here.

[0038] To demonstrate that at least some tin is atomically doped into the lattice of iron oxide, K-edge absorption spectroscopy of tin-doped iron oxide can be performed. The resulting absorption spectra can then be Fourier transformed to form an R-space diagram, as shown below. Figure 4 As shown, Figure 4 Curve 1 represents tin in atomic form doped into the iron oxide lattice (abbreviated as SA-Sn-Fe2O3), curve 2 represents tin in non-atomic form doped into the iron oxide lattice (abbreviated as Sn-Fe2O3), and curve 3 represents tin oxide (abbreviated as SnO2). In curve 1, the characteristic Sn-O-Fe peak is present in the range of 2 to 3 Å for R. In curves 2 and 3, the characteristic Sn-O-Fe peak is not present in the range of 2 to 3 Å for R. O represents oxygen. Fe is the symbol for iron. The appearance of the Sn-O-Fe characteristic peak indicates that Sn forms bonds with O atoms in O-Fe in atomic form, meaning that Sn enters the iron oxide lattice in atomic form. In tin-doped iron oxide, all Sn may enter the iron oxide lattice in atomic form, or only some Sn may enter the iron oxide lattice in atomic form. Regardless of how much Sn enters the iron oxide lattice in atomic form, the Sn-O-Fe characteristic peak will appear in the R space diagram.

[0039] Furthermore, when the molar percentage of tin in tin and iron is greater than 0 and less than or equal to 8%, Sn can enter the lattice of iron oxide in atomic form. As the molar percentage of tin gradually increases, the intensity of the Sn-O-Fe characteristic peak gradually increases, indicating that the added tin gradually aggregates to form the tin oxide phase. Therefore, by adjusting the molar percentage of tin, the physical form of tin can be controlled.

[0040] The intensity of the Sn-O-Fe characteristic peak in the R space diagram is greater than or equal to 2.0. This indicates that the Sn-O-Fe characteristic peak has a relatively large intensity, and therefore indicates that the Sn-O-Fe characteristic peak is not a spurious peak caused by interference. In other words, when the intensity of the characteristic peak in the R range of 2 to 3 Å is greater than or equal to 2.0, the characteristic peak appearing in this range can be considered as the Sn-O-Fe characteristic peak, thus avoiding the influence of spurious peaks on the detection results.

[0041] exist Figure 4In the R-space diagram shown, curves 1, 2, and 3 all exhibit Sn-O characteristic peaks in the range of 1 to 2 Å within the R region. These Sn-O peaks indicate that Sn atoms are bonded to O atoms in iron oxide, potentially representing tin oxide. This suggests that Sn atoms have captured O from the iron oxide to form tin oxide, which is likely physically mixed with the iron oxide, meaning Sn is not actually incorporated into the iron oxide lattice. Furthermore, when Sn does not enter the iron oxide lattice atomically, almost all of it will likely bond with O to form tin oxide, resulting in a relatively large amount of tin oxide. Therefore, the intensities of the Sn-O characteristic peaks in curves 2 and 3 are quite similar. When some Sn enters the iron oxide lattice atomically, the remaining Sn will bond with O to form tin oxide, resulting in a relatively small amount of tin oxide. Therefore, the intensity of the Sn-O characteristic peak in curve 1 is lower than that in curve 2. Furthermore, the intensity ratio of the Sn-O characteristic peak to the Sn-O-Fe characteristic peak in curve 1 is less than or equal to 5.0, indicating that the intensity of the Sn-O-Fe characteristic peak is not lower than that of the Sn-O characteristic peak. From this perspective, if the intensity ratio of the Sn-O characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 5.0, it can also be considered that the characteristic peak appearing in the range of 2 to 3 angstroms is not a spurious peak but a Sn-O-Fe characteristic peak, thus avoiding the influence of spurious peaks on the detection results.

[0042] Furthermore, in curves 1, 2, and 3, a Sn-O-Sn characteristic peak exists in the range of 3.5 Å to 4 Å for R. This Sn-O-Sn characteristic peak indicates that multiple Sn atoms are bonded to O atoms. The corresponding substance may be agglomerated tin oxide or tin oxide particles. Agglomerated tin oxide or tin oxide particles are likely in a physically mixed state with iron oxide, so Sn atoms are not doped into the iron oxide lattice. Moreover, when Sn does not enter the iron oxide lattice in atomic form, almost all Sn will likely bond with O to form tin oxide, resulting in a relatively large amount of tin oxide. Consequently, this tin oxide is more likely to agglomerate and form particles, hence the relatively large and similar intensities of the Sn-O-Sn characteristic peaks in curves 2 and 3. When Sn enters the iron oxide lattice in atomic form, the likelihood of agglomeration is low due to the smaller amount of tin oxide formed, so the intensity of the Sn-O-Sn characteristic peak in curve 1 is low or even negligible. Furthermore, if the intensity ratio of the Sn-O-Sn characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 0.1, it indicates that the Sn-O-Fe characteristic peak has a higher intensity than the Sn-O-Sn characteristic peak. From this perspective, if the intensity ratio of the Sn-O-Sn characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 0.1, it can also be considered that the characteristic peak appearing in the range of 2 to 3 angstroms is not a spurious peak but a Sn-O-Fe characteristic peak, thus avoiding the influence of spurious peaks on the detection results.

[0043] See also Figure 3 As shown, the gas sensor may further include: two heating terminals 11 and two electrode terminals 31, the heating terminals 11 being connected to the heating layer 10, and the electrode terminals 31 being connected to the test electrodes within the electrode layer 30. Figure 3 (Not shown in the diagram) Connection; wherein, both the heating terminal 11 and the electrode terminal 31 can be made of conductive materials. The heating layer can be made of, but is not limited to, ruthenium oxide, chromium, or other materials with similar functions. The test electrode can be made of, but is not limited to, gold, platinum, silver, palladium, or other conductive materials. The test electrode can be, but is not limited to, planar electrodes or interdigitated electrodes, etc., and can be set according to actual needs, without specific limitations here. In this way, the heating terminal 11 can supply power to the heating layer 10, causing the heating layer to heat up. The heat generated is transferred to the gas-sensitive layer 40, heating the material of the gas-sensitive layer 40 to the working temperature. The resistance value of the gas-sensitive layer 40 is related to the characteristics of the gas substance it contacts, and can be used to detect the composition and concentration of a specific gas. Therefore, when the material in the gas-sensitive layer 40 at the working temperature contacts a specific gas, if the gas concentration reaches a certain level, the resistance value of the gas-sensitive layer 40 will change. The resistance value of the gas-sensitive layer 40 can be detected by the test electrode and output through the electrode terminal 31, thereby realizing the detection of a specific gas.

[0044] like Figure 5 As shown, the gas sensor may also include a base 61 and a sensing component 62. The sensing component 62 includes: a heating layer 10, an insulating layer 20, an electrode layer 30, a gas-sensitive layer 40, a heating terminal 11, and an electrode terminal 31. Figure 5 The heating layer 10, insulating layer 20, electrode layer 30, gas-sensitive layer 40, heating terminal 11, and electrode terminal 31 are not shown. The sensing component 62 is fixed to the base 61 by a support column 63. The heating transmission component 64 and the electrode transmission component 65 can be rod-shaped and fixed at intervals in the base 61. The rod-shaped heating transmission component 64 and the electrode transmission component 65 can surround the support column 63. The heating transmission component 64 can be connected to the heating terminal in the sensing component 62 via a connecting wire 66. Figure 7 (Not shown in the image) can be connected, and the electrode transmission element 65 can be connected to the electrode terminals in the sensing element 62 via the connecting wire 66. Figure 7 (Not shown in the image) This connection shortens the length of the connecting line 66 between the sensing element 62 and the heating transmission element 64, as well as the length of the connecting line 66 between the sensing element 62 and the electrode transmission element 65. Thus, the sensing element 62 is supported by the support column 63 and moved away from the base 61, which facilitates better contact between the sensing element 62 and the surrounding gas, thereby improving the detection performance of the gas sensor.

[0045] Of course, the structure of a gas sensor is not limited to Figure 5 As shown, the gas sensor may not include the base 61. In this case, the sensing component 62 is placed directly on the surface of a structure as a gas sensor. Alternatively, the gas sensor may be other structures. Any structure that can realize the function of a gas sensor is within the protection scope of the embodiments of this application.

[0046] For example, the structure of the sensing component 62 can be constructed in several ways:

[0047] Method 1: The sensing component 62 has a planar structure, such as... Figure 3 As shown, the insulating layer 20 is a planar structure, and the heating layer 10, electrode layer 30 and gas-sensitive layer 40 are also planar structures. For example, the insulating layer 20 can be, but is not limited to, a planar ceramic sheet. The heating layer 10 is disposed on one side of the planar ceramic sheet, and the electrode layer 30 and gas-sensitive layer 40 are disposed on the other side of the planar ceramic sheet. The heating terminal 11 can be disposed at the edge of the heating layer 11, and the electrode terminal 31 is disposed at the edge of the electrode layer 30. The heating terminal 11 and the electrode terminal 31 are insulated from each other, which facilitates the connection of leads between the heating terminal 11 and the electrode terminal 31.

[0048] Method 2: The sensing component 62 has a tubular structure, such as... Figure 6 As shown, Figure 6(a) in the figure is a three-dimensional structural schematic diagram of the sensing component 62. To avoid making the figure too complicated, Figure 6 In (a) of the diagram, the gas-sensitive layer 40 and the heating wire 10a are not shown. Figure 6 (b) is a cross-sectional view of the sensing component 62 perpendicular to the extension direction of the tubular structure. At this time, the insulating layer 20 is a tubular structure, and the heating wire 10a can be used as a heating component and is located on the inner wall of the tubular structure. At this time, the heating wire 10a acts as a heating layer. The wire 30a is wound around the outer wall surface of the tubular structure as a test electrode in the electrode layer. A gas-sensitive layer 40 is formed on the surface of the test electrode. The end of the heating wire 10a can be used as a heating terminal 11 located at both ends of the tubular structure, and the end of the wire 30a (not shown in the figure) can be used as an electrode terminal. This facilitates the connection of the heating terminal and the electrode terminal with leads.

[0049] Method 3: The sensing component 62 is a MEMS chip. In this case, the sensing component 62 can also be referred to as a sensing chip, such as... Figure 7 As shown, Figure 7 In diagram (a), the explosion structure of each membrane layer is shown, and Figure 7 Substrate 51 is not shown in (a) of the image. Figure 7 Image (b) is a top view showing the stacked film layers. In this view, the heating layer 10, insulating layer 20, electrode layer 30, gas-sensitive layer 40, heating terminal 11, and electrode terminal 31 are all disposed on the substrate 51. The substrate 51 can be, but is not limited to, a silicon substrate. The heating layer 10, insulating layer 20, electrode layer 30, gas-sensitive layer 40, heating terminal 11, and electrode terminal 31 are all fabricated using MEMS technology. The heating terminal 11 and electrode terminal 31 are located at the corners of the substrate 51 to facilitate lead connection. The heating layer 10, electrode layer 30, and gas-sensitive layer 40... The heating layer 10, electrode layer 30, and gas-sensitive layer 40 are positioned at the center of the substrate 51, and their projections onto the surface of the substrate 51 completely overlap. This allows the heat generated by the heating layer 10 to be more effectively applied to the gas-sensitive layer 40, and the electrode layer 30 to effectively monitor the resistance value of the gas-sensitive layer 40, thereby improving the accuracy of gas detection. The insulating layer 20 can cover the entire substrate 51 or a portion of it. Regardless of the coverage area of ​​the insulating layer 20, it is sufficient as long as it can isolate the heating layer 10 and the electrode layer 30; the specific coverage area is not limited here. This allows the sensing component 62 to have the characteristics of small size, low power consumption, and high reliability. If this sensing component 62 is directly applied as a gas sensor in a battery pack, interference with other structures within the battery pack can be avoided. Of course, the specific structure of the sensing chip is not limited to this. Figure 7 As shown, Figure 7 The example shown is just one type of sensor chip. The sensor chip can also be designed with other structures. Any structure that can be fabricated using MEMS technology is within the protection scope of this application.

[0050] Based on the above, this application also provides a method for preparing tin-doped iron oxide. This method may include: mixing a tin-containing raw material, an iron-containing raw material, an organic raw material, and a surfactant, followed by a hydrothermal reaction to obtain an intermediate. This intermediate is a substance with an MOF (Metal-Organic Frameworks) structure and containing tin and iron; and heat-treating the intermediate to obtain... Figure 8 The tin-doped iron oxide shown is formed by at least a portion of the tin being doped into the lattice of the iron oxide in atomic form, thereby achieving atomic-level doping of tin in the iron oxide.

[0051] The tin-containing raw materials can be, but are not limited to, tin chloride, etc.; the iron-containing raw materials can be, but are not limited to, ferric chloride, etc.; the organic raw materials can be, but are not limited to, 2-aminoterephthalic acid, etc.; and the surfactants can be, but are not limited to, F-127, etc. It should be understood that F-127 is one type of polyoxyethylene-polyoxypropylene copolymer. The conditions for the hydrothermal reaction include: a reaction temperature not exceeding 200℃ and a reaction time of 12-36 hours. The conditions for the heat treatment include: a reaction temperature not exceeding 800℃ and a reaction time not exceeding 12 hours. Of course, the conditions for the hydrothermal reaction and the heat treatment can be set according to factors such as the type of raw materials selected, and are not specifically limited here.

[0052] For example, the process of fabricating tin-doped iron oxide may include:

[0053] Step 1: Dissolve a certain amount of surfactant in a certain amount of deionized water and stir thoroughly to obtain solution A;

[0054] Step 2: Prepare a mixture of tin-containing and iron-containing raw materials so that the molar percentages of Sn and Fe meet a certain ratio;

[0055] Step 3: Add the mixture to solution A and stir. Then add a certain amount of glacial acetic acid and a certain amount of 2-aminoterephthalic acid in sequence and continue stirring to obtain solution B.

[0056] Step 4: Transfer solution B to a high-pressure reactor with a polytetrafluoroethylene liner and place it in a constant temperature oven to react at a certain temperature for a period of time. Then, obtain the intermediate by centrifugation, washing and drying.

[0057] Step 3: Place the intermediate in a crucible and heat it in a muffle furnace to a certain temperature for calcination to obtain tin-doped iron oxide, with tin being doped into the iron oxide lattice in atomic form.

[0058] Based on the above, this application also provides a method for manufacturing a sensing component in a gas sensor. When the sensing component has a planar structure, the manufacturing method may include: forming a heating layer and a heating terminal on one surface of an insulating layer, and leading out two leads and soldering them to the heating terminal; forming an electrode layer and an electrode terminal on the other surface of the insulating layer, and leading out two leads and soldering them to the electrode terminal; and forming a gas-sensitive layer on top of the electrode layer, thereby obtaining the sensing component. The heating layer and electrode layer can be formed, but are not limited to, by methods such as screen printing.

[0059] When the sensing component is a tubular structure, the manufacturing method may include: winding wires around the two ends of the outer wall of the tubular insulating layer (i.e., the insulating tube) to form two test electrodes, and welding the two leads to the ends of the two test electrodes respectively, wherein the ends of the test electrodes are electrode terminals; placing a heating wire inside the insulating tube, and leading out two leads to weld to the ends of the heating wire, wherein the ends of the heating wire are heating terminals, and the heating wire can act as a heating layer; and then forming a gas-sensitive layer on the outer wall surface of the insulating tube, thereby obtaining the sensing component.

[0060] When the sensing component is a MEMS chip, the fabrication method may include: using patterning technology to form a mask layer with a certain pattern on one side surface of a substrate; using a coating technology to deposit a heating material on the mask layer, and then removing the mask layer, so that part of the heating material remains on the substrate and part of the heating material is removed, thereby forming a heating layer and a heating terminal on the substrate; using a coating technology to sequentially form an insulating layer and an electrode layer on the heating layer, etching the electrode layer to etch test electrodes and electrode terminals in the electrode layer; soldering the heating terminal and the electrode terminal to leads respectively; and forming a gas-sensitive layer on the electrode layer to obtain the sensing component. Wherein, if the substrate is a silicon substrate, a bottom insulating layer can be formed between the silicon substrate and the heating layer to separate the silicon substrate and the heating layer, avoiding adverse effects of the silicon substrate on the heating layer. For example, the bottom insulating layer may be, but is not limited to, silicon nitride, silicon oxide, etc.; if the substrate is an insulating substrate, the heating layer can be directly fabricated on the insulating substrate. Furthermore, the insulating layer located between the heating layer and the electrode layer can be a single layer or a multi-layer structure. Regardless of the number of layers, the material used to make the insulating layer can be at least one of other insulating materials, including but not limited to silicon nitride, silicon oxide, and aluminum oxide. The specific design can be tailored to actual needs.

[0061] For example, the specific implementation process for forming the gas-sensitive layer may include: mixing a certain amount of gas-sensitive material with a certain amount of binder, such as but not limited to Triton, and grinding thoroughly to obtain a slurry; uniformly coating the slurry onto the electrode layer, and then performing heat treatment to remove the binder and increase the stability of the film layer, thereby forming a gas-sensitive layer with a certain thickness. The thickness of the gas-sensitive layer can be approximately 10 nm to 80 nm, and can be set according to actual conditions; no limitation is made here.

[0062] Based on the above, this application also provides a battery pack, such as... Figure 9 As shown, Figure 9 The illustration uses only one gas sensor as an example. The battery pack includes: a housing 101, a secondary battery 102, and a gas sensor 103 as described above. The secondary battery 102 and the gas sensor 103 are located inside the housing 101. The gas sensor 103 is used to detect the hydrogen concentration inside the housing 101. This allows for the detection and monitoring of the hydrogen concentration inside the battery pack, thereby preventing thermal runaway and improving the safety and reliability of the battery pack.

[0063] In cases where the secondary battery 102 has an explosion-proof valve, since hydrogen gas typically leaks out from the valve and the hydrogen gas concentration near the valve is generally higher, the gas sensor 103 can be placed near the explosion-proof valve. This allows the gas sensor to come into contact with the hydrogen gas as early as possible, improving detection accuracy. Since the battery pack usually includes multiple secondary batteries 102, the gas sensor 103 can be placed near the explosion-proof valve of any secondary battery 102, such as, but not limited to, placing the gas sensor 103 near the explosion-proof valve of a secondary battery 102 located on the side, or placing the gas sensor 103 near the explosion-proof valve of a secondary battery 102 located in the middle, etc. These are not listed here. Of course, besides placing the gas sensor near the explosion-proof valve, it can also be placed in other locations, such as, but not limited to, placing the gas sensor 103 on the surface of the end plate when the battery pack also includes an end plate. The specific placement can be determined according to actual needs and is not specifically limited here.

[0064] Furthermore, the number of gas sensors 103 in the battery pack layout can be one, two, or more, depending on the actual situation. For example, increasing the number of gas sensors 103 and distributing them in different locations within the battery pack allows for the detection of hydrogen concentration at different locations, thus enabling more accurate monitoring of the hydrogen concentration in the battery pack. Therefore, to increase the accuracy of monitoring, the number of gas sensors 103 can be increased. Alternatively, increasing the number of gas sensors 103 may increase the cost of the battery pack and occupy more space, potentially affecting the layout of other structures. Therefore, to reduce costs and avoid impacting the layout of other structures, the number of gas sensors 103 can be reduced.

[0065] The performance of tin-doped iron oxide was tested below.

[0066] Example: The gas-sensitive material is tin-doped iron oxide, and at least a portion of the tin is doped into the lattice of the iron oxide in atomic form.

[0067] Comparative Example: The difference from the example is that tin is doped into the iron oxide lattice in a non-atomic form.

[0068] Figure 10 The figure shows the response of the embodiments and comparative examples to different concentrations of hydrogen. The horizontal axis represents time, and the vertical axis represents the response value. The results in the figure show that the response value of the embodiments is higher than that of the comparative examples, especially in high concentration hydrogen environments, such as when the hydrogen concentration is greater than 250 ppm. The response value of the embodiments is better than that of the comparative examples. This shows that when at least some tin is doped into the lattice of iron oxide in a non-atomic form, it can generate more active sites in the gas-sensitive layer, thereby allowing the gas-sensitive layer to absorb more hydrogen. This characteristic may not be particularly obvious when the hydrogen concentration is low, but it will be fully demonstrated when the hydrogen concentration is high, thus showing a higher response value. Since a higher response value indicates a higher detection sensitivity, the gas sensor containing the gas-sensitive material in the embodiments has superior performance.

[0069] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A gas sensor, characterized in that, include: A heating layer, an insulating layer, an electrode layer, and a gas-sensitive layer are stacked in sequence. The gas-sensitive layer is made of tin-doped iron oxide, with at least a portion of the tin being atomically doped into the lattice of the iron oxide.

2. The gas sensor as described in claim 1, characterized in that, In the atomic radius R space diagram of the tin-doped iron oxide, there is a Sn-O-Fe characteristic peak in the range of 2 Å to 3 Å. The R space diagram is the spectrum formed by performing a Fourier transform on the absorption spectrum obtained after performing a K-edge absorption spectrum test on the tin-doped iron oxide for tin.

3. The gas sensor as described in claim 2, characterized in that, The intensity of the Sn-O-Fe characteristic peak in the R space diagram is greater than or equal to 2.

0.

4. The gas sensor as described in claim 2 or 3, characterized in that, In the R space diagram, there is a Sn-O characteristic peak in the range of 1 to 2 angstroms, and the intensity ratio of the Sn-O characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 5.

0.

5. The gas sensor according to any one of claims 2-4, characterized in that, In the R space diagram, there is a Sn-O-Sn characteristic peak in the range of 3.5 Å to 4 Å, and the intensity ratio of the Sn-O-Sn characteristic peak to the Sn-O-Fe characteristic peak is less than or equal to 0.

1.

6. The gas sensor according to any one of claims 1-5, characterized in that, The heating layer is used to provide heat to the gas-sensitive layer, the insulating layer is used to isolate the heating layer and the electrode layer, and the electrode layer is used to detect the resistance value of the gas-sensitive layer.

7. The gas sensor according to any one of claims 1-6, characterized in that, The insulating layer has a planar structure.

8. The gas sensor according to any one of claims 1-6, characterized in that, The insulating layer is a tubular structure, the heating layer is disposed on the inner wall of the tubular structure, and the electrode layer and the gas-sensitive layer are disposed on the outer wall of the tubular structure; The gas sensor further includes a heating terminal and an electrode terminal, wherein the heating terminal is connected to the heating layer, and the electrode terminal is connected to a test electrode within the electrode layer; The heating terminals are located at both ends of the tubular structure; The electrode terminals are wound around the outer wall of the tubular structure.

9. The gas sensor according to any one of claims 1-8, characterized in that, The gas sensor is a MEMS chip.

10. A battery pack, characterized in that, include: The enclosure, the secondary battery, and the gas sensor as described in any one of claims 1-9, wherein the secondary battery and the gas sensor are disposed within the enclosure; the gas sensor is used to detect the hydrogen concentration within the enclosure.

11. An energy storage system, characterized in that, Includes the battery pack and power converter as described in claim 10, wherein the power converter is used to convert AC power output from an external AC power source into DC power output to the battery pack, and / or, the power converter is used to convert DC power output from the battery pack into AC power output to a load or power grid.

12. A new energy vehicle, characterized in that, include: The electric motor and the battery pack as described in claim 10, wherein the battery pack is used to provide driving power to the electric motor.

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