Hydrogen sulfide detection device

Abstract

The present invention provides a hydrogen sulfide detection device that can be applied to battery packs containing battery cells having a sulfide electrolyte and is capable of detecting the generation of hydrogen sulfide with high accuracy. [Solution] The hydrogen sulfide detection device comprises a substrate having a pattern formed of a metal that corrodes in reaction with hydrogen sulfide, and a monitoring circuit that monitors the voltage between a first node and a second node. The first metal part is electrically connected to the first node, and the second metal part is electrically connected to the second node. The first metal part and the second metal part are electrically insulated from each other and are arranged adjacent to each other with a gap between them.

Description

Technical Field

[0001] The present disclosure relates to a hydrogen sulfide detection device applied to a battery pack that stores battery cells having a sulfide-based electrolyte.

Background Art

[0002] All-solid-state batteries have attracted attention as next-generation battery cells that make up battery packs. All-solid-state batteries have advantages such as high safety and long life compared to conventional batteries with liquid electrolytes. In particular, all-solid-state batteries using sulfide-based electrolytes have high capacity and high output and are expected to be used for vehicle batteries.

[0003] On the other hand, when a battery cell having a sulfide-based electrolyte is configured as a battery cell of an all-solid-state battery, hydrogen sulfide gas may be generated due to a failure. Hydrogen sulfide gas is toxic and corrodes surrounding metal parts. Therefore, there is a need for a technique for appropriately detecting the generation of hydrogen sulfide in a battery pack that stores battery cells having a sulfide-based electrolyte.

[0004] Patent Document 1 discloses a detection system that provides a resistance change member including a resistance change material whose electrical resistance changes due to a chemical reaction with hydrogen sulfide in a battery cell, and determines the presence or absence of hydrogen sulfide generation in the battery cell based on a detection value between terminals of the resistance change member. In addition, there is the following Patent Document 2 as a document showing the technical level of this technical field.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The detection system disclosed in Patent Document 1 detects the generation of hydrogen sulfide by detecting the change in electrical resistance of a resistance-changing material due to a chemical reaction with hydrogen sulfide. Since metals are usually used as the resistance-changing material, this configuration requires another resistor to prevent large currents from flowing through the detection circuit under normal conditions. As a result, the change in resistance of the metal due to the chemical reaction is negligible compared to the overall resistance of the detection circuit. Consequently, there is a problem with the detection accuracy of the detection system.

[0007] This disclosure has been made in view of the above-mentioned issues. One of the purposes of this disclosure is to provide a technology that can detect the generation of hydrogen sulfide with high accuracy. [Means for solving the problem]

[0008] One aspect of this disclosure relates to a hydrogen sulfide detection device applied to a battery pack housing a battery cell having a sulfide-based electrolyte. The hydrogen sulfide detection device comprises a substrate having a pattern formed of a metal that reacts with and corrodes in response to hydrogen sulfide, and a monitoring circuit that monitors the voltage between a first node and a second node. The first metal part is electrically connected to the first node, and the second metal part is electrically connected to the second node. The first and second metal parts are electrically insulated from each other and are arranged adjacent to each other with a gap between them. [Effects of the Invention]

[0009] According to this disclosure, the generation of hydrogen sulfide is detected when the sulfide of the metal produced by the reaction with hydrogen sulfide creates an electrical connection between the first metal part and the second metal part. At this time, the voltage between the first node and the second node changes significantly. Therefore, the generation of hydrogen sulfide can be detected with high accuracy. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of a hydrogen sulfide detection device according to the first embodiment. [Figure 2]This is a schematic diagram illustrating the operation of a hydrogen sulfide detection device. [Figure 3] This graph shows an example of detected values ​​in a monitoring circuit. [Figure 4] This is a flowchart showing the processing flow of the monitoring circuit. [Figure 5] This is a schematic diagram showing the configuration of a hydrogen sulfide detection device according to the second embodiment. [Figure 6] This is a schematic diagram showing the configuration of a hydrogen sulfide detection device according to the third embodiment. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the attached drawings. In each drawing, identical or corresponding components are denoted by the same reference numerals, and their descriptions are simplified or omitted.

[0012] 1. First Embodiment 1.1 Configuration Figure 1 is a schematic diagram showing the configuration of a hydrogen sulfide detection device 10 according to the first embodiment. The hydrogen sulfide detection device 10 is applied to a battery pack that houses battery cells having a sulfide electrolyte and detects the generation of hydrogen sulfide. The hydrogen sulfide detection device 10 is housed in the battery pack together with the battery cells. The battery cells having a sulfide electrolyte are typically all-solid-state batteries using a solid sulfide electrolyte. The form of the battery cell is not particularly limited. For example, the form of the battery cell may be laminated or prismatic. All-solid-state batteries using sulfide electrolytes have high capacity and high output and are suitable for vehicle batteries. Therefore, the battery pack to which the hydrogen sulfide detection device 10 is applied may be a battery mounted in a vehicle.

[0013] The hydrogen sulfide detection device 10 comprises a monitoring circuit 100 and a substrate 200. The substrate 200 is a printed circuit board (PCB) having a pattern 220 formed of metal. The substrate 200 may also be a flexible printed circuit board (FPC).

[0014] The monitoring circuit 100 and the circuit board 200 are connected to external devices via connectors 110 and 210, respectively. As shown in Figure 1, the monitoring circuit 100 and the circuit board 200 are connected by cable 300.

[0015] The monitoring circuit 100 monitors the voltage between the first node 401 and the second node 402. In the monitoring circuit 100, the first node 401 is connected to a power supply with voltage Vcc (e.g., 5V) via a resistor 120, and the second node 402 is connected to ground GND at a reference potential (e.g., 0V). The monitoring circuit 100 includes a monitoring processing unit 130. The monitoring processing unit 130 is a computer that performs the process of monitoring the voltage. In particular, the monitoring processing unit 130 may be a microcontroller. The monitoring processing unit 130 is configured to receive the potential between the resistor 120 and the first node 401 as input. For example, when the monitoring processing unit 130 is a microcontroller, the input port of the microcontroller is connected between the resistor 120 and the first node 401. The resistor 120 acts as a pull-up resistor for the monitoring processing unit 130. For example, the resistance value of the resistor 120 is about 10kΩ. Since the second node 402 is connected to ground GND, the monitoring processing unit 130 can detect the voltage between the first node 401 and the second node 402.

[0016] Furthermore, the voltage between the first node 401 and the second node 402 can also be indirectly detected by measuring the voltage across the resistor 120. Therefore, monitoring the voltage between the first node 401 and the second node 402 includes monitoring the voltage across the resistor 120. From this perspective, the monitoring processing unit 130 may be configured to measure the voltage across the resistor 120.

[0017] The monitoring processing unit 130 includes one or more processors 131 (hereinafter simply referred to as the processor 131) and one or more storage devices 132 (hereinafter simply referred to as the storage device 132). The processor 131 executes various processes. The processor 131 is composed of, for example, a general-purpose processor, a special-purpose processor, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), an integrated circuit, a conventional circuit, and one or more combinations thereof. The processor 131 can also be referred to as processing circuitry. The storage device 132 stores various information necessary for the execution of the processes by the processor 131. The storage device 132 is composed of, for example, recording media such as a RAM (Random Access Memory), a ROM (Read Only Memory), a SSD (Solid State Drive), a HDD (Hard Disk Drive), etc. The storage device 132 stores a computer program executable by the processor 131. The computer program is composed of a plurality of instruction codes describing the processes to be executed by the processor 131. The computer program is recorded on a computer-readable recording medium. The functions of the monitoring processing unit 130 are realized by the cooperation of the processor 131 that executes the computer program and the storage device 132.

[0018] The metal used to form the pattern 220 on the substrate 200 is a metal that reacts with hydrogen sulfide and corrodes. For example, copper or silver is used as the metal. Furthermore, the pattern 220 on the substrate 200 includes a first metal portion 501 and a second metal portion 502. The first metal portion 501 and the second metal portion 502 are each formed such that the metal is exposed on the surface of the substrate 200. This can be achieved by configuring the substrate 200 so that surface protection (e.g., solder resist, coverlay) or surface treatment (e.g., plating) is not performed on the first metal portion 501 and the second metal portion 502. Furthermore, in the first embodiment, the first metal portion 501 and the second metal portion 502 are formed by vias or through-holes. Vias or through-holes generally have a circular shape and have a structure in which the inner surface of the hole is covered with metal.

[0019] Through the wiring formed by the cable 300 and the pattern 220, the first metal portion 501 is connected to the first node 401, and the second metal portion 502 is connected to the second node 402. As shown in FIG. 1, the first metal portion 501 and the second metal portion 502 are arranged adjacent to each other with a gap (distance d) therebetween. Particularly in the example shown in FIG. 1, the distance d between the first metal portion 501 and the second metal portion 502 is shorter than the width w1 of the first metal portion 501 and the width w2 of the second metal portion 502. Here, the width w1 of the first metal portion 501 is the diameter when the first metal portion 501 is circular, the long side when it is rectangular, and the major axis when it is elliptical. The same applies to the width w2 of the second metal portion 502. Furthermore, due to surface protection or the like applied to the substrate 200, the first metal portion 501 and the second metal portion 502 are electrically insulated. That is, the space between the first metal portion 501 and the second metal portion 502 is in a non-conductive state.

[0020] As described above, the hydrogen sulfide detection device 10 according to the first embodiment is configured. Hereinafter, the operation of the hydrogen sulfide detection device 10 described above will be described in detail.

[0021] 1.2 Operation of Hydrogen Sulfide Detection Device Figure 2 is a schematic diagram illustrating the operation of the hydrogen sulfide detection device 10. (A) in Figure 2 shows the operation when the target battery pack is functioning normally. In other words, it shows the operation when no hydrogen sulfide is being generated from the battery cells. Under normal conditions, as described above, the first metal part 501 and the second metal part 502 are electrically insulated, so there is no conductivity between the first metal part 501 and the second metal part 502. Therefore, as shown in the transmission path TR1, the power supply voltage Vcc is input directly to the monitoring processing unit 130. That is, the monitoring processing unit 130 acquires the power supply voltage Vcc as the detected value.

[0022] Figure 2(B) shows the operation during an abnormal situation, i.e., when hydrogen sulfide is generated from the battery cell. At this time, the metals of the first metal part 501 and the second metal part 502 react with the generated hydrogen sulfide and corrode. The sulfide 510 produced by the corrosion of the metal tends to spread radially. This is also called sulfide creep. As the sulfide 510 spreads in both the first metal part 501 and the second metal part 502, the first metal part 501 and the second metal part 502 become connected by the sulfide 510, as shown in Figure 2(B). Since the sulfide 510 is conductive, this creates an electrical connection between the first metal part 501 and the second metal part 502.

[0023] Thus, when hydrogen sulfide is generated from the battery cell, conduction occurs between the first metal part 501 and the second metal part 502, forming a single current path between the first node 401 and the second node 402. At this time, the monitoring and processing unit 130 acquires the voltage division due to the resistance between the first node 401 and the second node 402 as a detected value. Here, the first metal part 501 and the second metal part 502 are adjacent to each other, and the resistance of the sulfide 510 connecting the first metal part 501 and the second metal part 502 is minute compared to the resistance 120. Therefore, as shown in the transmission path TR2, the potential of the ground GND is input to the monitoring and processing unit 130 almost as is. In other words, the monitoring and processing unit 130 acquires the reference potential as a detected value.

[0024] Figure 3 is a graph showing an example of the detection value of the monitoring and processing unit 130 when the reference potential is 0V. The example shown in Figure 3 shows that hydrogen sulfide is generated from the battery cell at time Ts. As shown in the graph, before hydrogen sulfide is generated from the battery cell, the detection value of the monitoring and processing unit 130 is Vcc. Then, when hydrogen sulfide is generated from the battery cell at time Ts, the detection value of the monitoring and processing unit 130 changes rapidly from Vcc to 0V. Therefore, the monitoring and processing unit 130 can determine whether or not hydrogen sulfide is being generated from the battery cell based on the detection value (voltage between the first node 401 and the second node 402). For example, the monitoring and processing unit 130 determines that hydrogen sulfide is being generated from the battery cell when the amount of change from the initial value of the detection value becomes larger than a threshold. Alternatively, for example, the monitoring and processing unit 130 may use the detection value as is without calculating the amount of change in the detection value, and determine that hydrogen sulfide is being generated from the battery cell when the detection value becomes smaller than a threshold.

[0025] Figure 4 is a flowchart showing the processing flow of the monitoring circuit 100 (more specifically, the monitoring processing unit 130). The processing flow shown in Figure 4 is executed repeatedly at predetermined processing cycles.

[0026] First, in step S110, the monitoring circuit 100 acquires the detected value. Next, in step S120, the monitoring circuit 100 calculates the amount of change from the initial value of the detected value. In the hydrogen sulfide detection device 10 described above, the initial value of the detected value is the power supply voltage Vcc, and the amount of change from the initial value is the difference between the detected value and Vcc. Next, in step S130, the monitoring circuit 100 determines whether the calculated amount of change is greater than a threshold value.

[0027] If the fluctuation amount is below the threshold (step S130; No), the monitoring circuit 100 terminates the process, determining that no hydrogen sulfide is being generated. If the fluctuation amount is greater than the threshold (step S130; Yes), the monitoring circuit 100 determines that hydrogen sulfide is being generated from the battery cell (step S140). The monitoring circuit 100 may further execute a process to warn the user (e.g., vehicle driver) that hydrogen sulfide is being generated by display or sound.

[0028] 1.3 Effects As described above, the hydrogen sulfide detection device 10 according to the first embodiment can detect the generation of hydrogen sulfide from a battery cell. In particular, with the hydrogen sulfide detection device 10 described above, when hydrogen sulfide is generated from a battery cell, the voltage between the first node 401 and the second node 402 changes rapidly from Vcc to a reference potential. Because the detected value changes so significantly, the hydrogen sulfide detection device 10 can detect the generation of hydrogen sulfide with high accuracy. Furthermore, it is possible to configure the hydrogen sulfide detection device 10 by reusing existing substrates used for monitoring the voltage of battery cells, etc. This allows the hydrogen sulfide detection device 10 to be constructed at low cost.

[0029] Furthermore, according to the first embodiment, the distance d between the first metal part 501 and the second metal part 502 is shorter than the width w1 of the first metal part 501 and the width w2 of the second metal part 502. The width w1 of the first metal part 501 is related to the amount of sulfide 510 produced from the first metal part 501 by reaction with hydrogen sulfide. In other words, the larger the width w1, the greater the amount of sulfide 510 produced from the first metal part 501. Similarly, the width w2 of the second metal part 502 is related to the amount of sulfide 510 produced from the second metal part 502 by reaction with hydrogen sulfide. Therefore, by making the distance d shorter than the widths w1 and w2, the amount of sulfide 510 produced from the first metal part 501 and the second metal part 502 can be ensured to be sufficient to create a conductive state between the first metal part 501 and the second metal part 502. Furthermore, when hydrogen sulfide is generated from the battery cell, the time required for electrical conductivity to be established between the first metal part 501 and the second metal part 502 can be significantly reduced. As a result, the detection accuracy of the hydrogen sulfide detection device 10 can be further improved.

[0030] Furthermore, according to the first embodiment, the first metal part 501 and the second metal part 502 are formed by vias or through holes. Since vias or through holes are circular holes, this configuration allows the sulfide 510 to spread monotonically. This makes it easier to predict the tendency of the sulfide 510 to spread, and simplifies the design of the substrate 200. In addition, the generated hydrogen sulfide remains inside the holes, allowing the first metal part 501 and the second metal part 502 to effectively generate sulfide 510. As a result, the detection accuracy of the hydrogen sulfide detection device 10 can be further improved.

[0031] Incidentally, the most likely location for hydrogen sulfide generation in a battery cell is the sealing portion of the battery cell's casing. This is because the sealing portion tends to have lower resistance to scratches than other parts. Therefore, the substrate 200, which serves as the hydrogen sulfide detection unit, may be configured to be positioned adjacent to the sealing portion of the battery cell's casing.

[0032] When a battery cell is laminated, its casing is typically a laminate film. When a battery cell is rectangular, its casing is typically a metal can. The sealing portion of the casing is, for example, located where it covers the electrode terminals of the battery cell.

[0033] By positioning the substrate 200 adjacent to the sealing portion of the battery cell's casing, the detection accuracy of the hydrogen sulfide detection device 10 can be improved.

[0034] 1.4 Variations In the first embodiment described above, the monitoring circuit 100 was configured such that the resistor 120 acts as a pull-up resistor for the monitoring processing unit 130. As a modification, the monitoring circuit 100 may be configured such that the resistor 120 acts as a pull-down resistor for the monitoring processing unit 130. That is, the first node 401 may be directly connected to the power supply, and the second node 402 may be connected to ground GND via the resistor 120. The monitoring processing unit 130 may then be configured to detect the voltage between the first node 401 and the second node 402. For example, the input port of the monitoring processing unit 130 may be connected between the resistor 120 and the second node 402.

[0035] In the modified hydrogen sulfide detection device 10, under normal conditions, the ground potential (GND) is directly input to the monitoring and processing unit 130. That is, the monitoring and processing unit 130 acquires the reference potential as the detected value. When hydrogen sulfide is generated from the battery cell, the first metal part 501 and the second metal part 502 become conductive, similar to the operation described above. As a result, the detected value of the monitoring and processing unit 130 changes rapidly from the reference potential to Vcc. Therefore, even in the modified version, the monitoring and processing unit 130 can determine whether or not hydrogen sulfide is being generated from the battery cell based on the detected value. The processing flow of the monitoring circuit 100 at this time may be the same as that shown in Figure 4. In the modified hydrogen sulfide detection device 10, the initial value of the detected value is the reference potential, and the amount of change from the initial value is the difference between the detected value and the reference potential. When the reference potential is 0V, the amount of change from the initial value matches the detected value.

[0036] Thus, the modified hydrogen sulfide detection device 10 can also achieve the same effects as described above.

[0037] 2. Second Embodiment The second embodiment will be described below. However, the following description will focus on the differences from the first embodiment, and explanations of content that overlaps with the first embodiment will be omitted as appropriate.

[0038] Figure 5 is a schematic diagram showing the configuration of the hydrogen sulfide detection device 10 according to the second embodiment. The hydrogen sulfide detection device 10 according to the second embodiment includes a monitoring circuit 100 and a substrate 200, similar to the first embodiment. The pattern 220 of the substrate 200 includes a first metal part 501 and a second metal part 502. In the second embodiment, the substrate 200 further has a groove 520 formed between the first metal part 501 and the second metal part 502. The groove 520 has a structure that is slightly recessed relative to the surface of the substrate 200.

[0039] The operation of the hydrogen sulfide detection device 10 according to the second embodiment is the same as that of the first embodiment. That is, the hydrogen sulfide detection device 10 detects the generation of hydrogen sulfide when the sulfide 510 produced by the reaction with hydrogen sulfide causes electrical conductivity between the first metal part 501 and the second metal part 502. On the other hand, according to the hydrogen sulfide detection device 10 according to the second embodiment, the groove 520 of the substrate 200 makes it easier for the sulfide 510 to spread between the first metal part 501 and the second metal part 502. This further shortens the time it takes for electrical conductivity to be achieved between the first metal part 501 and the second metal part 502. As a result, the detection accuracy of the hydrogen sulfide detection device 10 can be further improved.

[0040] 3. Third Embodiment The third embodiment will be described below. However, the following description will focus on the differences from the first embodiment, and explanations of content that overlaps with the first embodiment will be omitted as appropriate.

[0041] Figure 6 is a schematic diagram showing the configuration of the hydrogen sulfide detection device 10 according to the third embodiment. The hydrogen sulfide detection device 10 according to the third embodiment includes a monitoring circuit 100 and a substrate 200, similar to the first embodiment. The pattern 220 of the substrate 200 includes a first metal part 501 and a second metal part 502. In the third embodiment, the first metal part 501 and the second metal part 502 are formed by exposing a portion of the metal of the pattern 220 to the surface of the substrate 200. This can be achieved by configuring the substrate 200 so that surface protection or surface treatment is not applied to a portion of the pattern 220.

[0042] The operation of the hydrogen sulfide detection device 10 according to the third embodiment is the same as that of the first embodiment. That is, the hydrogen sulfide detection device 10 detects the generation of hydrogen sulfide when the sulfide 510 produced by the reaction with hydrogen sulfide causes an electrical connection between the first metal part 501 and the second metal part 502. On the other hand, in the hydrogen sulfide detection device 10 according to the third embodiment, since the first metal part 501 and the second metal part 502 are formed by a part of the pattern 220, there is no need to make the substrate 200 a multilayer structure. As a result, it is possible to construct the hydrogen sulfide detection device 10 at a lower cost. [Explanation of Symbols]

[0043] 10. Hydrogen sulfide detection device 100 Supervisory circuit 200 circuit boards 220 patterns 401 Node 1 402 Node 2 501 1st metal part 502 2nd metal part 520 groove section

Claims

1. A hydrogen sulfide detection device applied to a battery pack containing a battery cell having a sulfide-based electrolyte, A substrate having a pattern formed of a metal that corrodes in reaction with hydrogen sulfide, A monitoring circuit that monitors the voltage between the first node and the second node, Equipped with, The pattern includes a first metal portion and a second metal portion in which the metal is exposed on the surface of the substrate. The first metal part is electrically connected to the first node, The second metal part is electrically connected to the second node, The first metal part and the second metal part are electrically insulated from each other and are arranged adjacent to each other with a gap between them. Hydrogen sulfide detection device.

2. A hydrogen sulfide detection device according to claim 1, The distance between the first metal part and the second metal part is shorter than the width of the first metal part plus the width of the second metal part. Hydrogen sulfide detection device.

3. A hydrogen sulfide detection device according to claim 1, The substrate has a groove formed between the first metal portion and the second metal portion. Hydrogen sulfide detection device.

4. A hydrogen sulfide detection device according to claim 1, The first metal part and the second metal part are vias or through holes. Hydrogen sulfide detection device.

5. A hydrogen sulfide detection device according to any one of claims 1 to 4, The monitoring circuit determines whether or not hydrogen sulfide is being generated from the battery cell based on the change in voltage. Hydrogen sulfide detection device.

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