Hydrogen sulfide detection device

Abstract

The present invention provides a hydrogen sulfide detection device that can detect the generation of hydrogen sulfide at multiple locations within a battery pack containing battery cells with a sulfide electrolyte, while reducing costs. [Solution] The hydrogen sulfide detection device comprises wiring that electrically connects a first node and a second node, and a monitoring circuit that monitors the voltage between the first node and the second node. The wiring includes a plurality of exposed metal parts where metal that reacts with hydrogen sulfide and corrodes is exposed.

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 are attracting 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] In battery cells with sulfide-based electrolytes used in all-solid-state batteries, predicting the location of hydrogen sulfide generation is extremely difficult. Furthermore, predicting how the generated hydrogen sulfide will be distributed is also challenging. Therefore, to appropriately detect hydrogen sulfide generation, it is desirable to perform detection at multiple locations within the battery pack.

[0007] However, in the technology disclosed in Patent Document 1, a detection circuit is configured for each resistance-changing member, so if resistance-changing members are placed in multiple locations within the battery pack, the detection circuit becomes complex. Therefore, the high cost of performing detection at multiple locations within the battery pack becomes a problem. In addition, the space required to configure the detection system also becomes large.

[0008] This disclosure has been made in view of the above-mentioned issues. One objective of this disclosure is to provide a technology that can detect the generation of hydrogen sulfide at multiple locations within a battery pack while reducing costs. [Means for solving the problem]

[0009] One aspect of this disclosure relates to a hydrogen sulfide detection device applied to a battery pack containing a battery cell having a sulfide-based electrolyte. The hydrogen sulfide detection device comprises wiring electrically connecting a first node and a second node, and a monitoring circuit for monitoring the voltage between the first node and the second node. The wiring includes a plurality of metal exposures in which metals that react with and corrode hydrogen sulfide are exposed. [Effects of the Invention]

[0010] According to this disclosure, by arranging multiple exposed metal parts at multiple locations within the battery pack, the generation of hydrogen sulfide can be detected at multiple locations within the battery pack. Furthermore, according to this disclosure, the hydrogen sulfide detection device is configured with a monitoring circuit and a single wiring regardless of the number of detection locations, thus reducing costs. [Brief explanation of the drawing]

[0011] [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 is a flowchart showing the processing flow of the monitoring circuit. [Figure 4] This is a conceptual diagram showing an example of the arrangement of exposed metal parts. [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]

[0012] 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.

[0013] 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-based electrolyte and detects the generation of hydrogen sulfide. The hydrogen sulfide detection device 10 is housed together with the battery cells in the battery pack. The battery cells having a sulfide-based electrolyte are typically all-solid-state batteries using a solid sulfide-based electrolyte. The form of the battery cell is not particularly limited. For example, the form of the battery cell may be laminated or rectangular. All-solid-state batteries using sulfide-based 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.

[0014] The hydrogen sulfide detection device 10 comprises a monitoring circuit 100 and a plurality of substrates 200. Each of the plurality of substrates 200 is a printed circuit board (PCB) having the same pattern 220 formed of metal. Each substrate 200 may be a flexible printed circuit board (FPC).

[0015] The monitoring circuit 100 and the circuit board 200 are connected to external equipment via connectors 110 and 210, respectively. As shown in Figure 1, the monitoring circuit 100 and the multiple circuit boards 200 are connected in a daisy-chain configuration by a cable 300. This allows the cable 300 and the patterns 220 on each circuit board 200 to form wiring (hereinafter simply referred to as wiring) that electrically connects the first node 401 and the second node 402. The wiring forms a single current path.

[0016] 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.

[0017] Also, the voltage between the first node 401 and the second node 402 can be indirectly detected by measuring the voltage across the two ends of the resistor 120. Therefore, monitoring the voltage between the first node 401 and the second node 402 also includes measuring the voltage across the two ends of the resistor 120. From this perspective, the monitoring processing unit 130 may be arranged to measure the voltage across the two ends of the resistor 120.

[0018] The monitoring processing unit 130 includes one or more processors 131 (hereinafter simply referred to as processor 131) and one or more storage devices 132 (hereinafter simply referred to as storage device 132). The processor 131 executes various processes. The processor 131 is composed of, for example, a general-purpose processor, a dedicated 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), an SSD (Solid State Drive), an 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.

[0019] The metal used to form the pattern 220 of the substrate 200 is a metal that reacts with hydrogen sulfide and corrodes. For example, copper or silver is used as the metal. Further, in the first embodiment, a part of the pattern 220 of each substrate 200 forms a metal exposed portion 500 by the metal being exposed on the surface of the substrate 200. This can be realized by configuring the substrate 200 so that surface protection (e.g., solder resist, coverlay) or surface treatment (e.g., plating) is not performed on a part of the pattern 220. Thus, in the first embodiment, a part of the pattern 220 of each substrate 200 forms a metal exposed portion 500. As a result, as shown in FIG. 1, the wiring includes a plurality of metal exposed portions 500.

[0020] 1.2 Operation of Hydrogen Sulfide Detection Device Hereinafter, the operation of the hydrogen sulfide detection device 10 according to the first embodiment will be described. FIG. 2 is a schematic diagram for explaining the operation of the hydrogen sulfide detection device 10.

[0021] (A) in FIG. 2 shows the operation when the target battery pack is normal. That is, it shows the operation when hydrogen sulfide is not generated from the battery cell. In a normal state, the wiring simply becomes a current path having no resistance. Therefore, as shown by the transmission path TR, the potential of the ground GND is input to the monitoring processing unit 130 as it is. That is, the monitoring processing unit 130 acquires the reference potential as the detection value.

[0022] (B) in FIG. 2 shows the operation when hydrogen sulfide is generated from the battery cell. At this time, the metal of the metal exposed portion 500 reacts with the generated hydrogen sulfide and corrodes. When the metal becomes a sulfide due to corrosion, the resistance value of the metal exposed portion 500 increases. Further, the metal tends to move radially due to corrosion. Also, the corroded metal moves when vibration is applied. For example, when the vibration of a vehicle is transmitted, the corroded metal moves. As the corrosion progresses in this way, the metal of the metal exposed portion 500 gradually disappears and the cross-sectional area becomes smaller. As a result, the resistance value of the metal exposed portion 500 further increases. Finally, the metal of the metal exposed portion 500 will be disconnected.

[0023] As hydrogen sulfide is generated from the battery cell, the resistance of the exposed metal portion 500 increases, eventually leading to a break in the circuit. Therefore, during the process of the resistance of the exposed metal portion 500 increasing, the monitoring and processing unit 130 acquires the voltage division due to the resistance of the exposed metal portion 500 as a detected value. In other words, as the resistance of the exposed metal portion 500 increases, the detected value of the monitoring and processing unit 130 rises from the reference potential. Finally, when the exposed metal portion 500 breaks, the power supply voltage Vcc is input directly to the monitoring and processing unit 130. That is, the monitoring and processing unit 130 acquires the power supply voltage Vcc as a detected value.

[0024] Figure 2(B) shows a graph of an example of the detection value of the monitoring and processing unit 130 when the reference potential is 0V. As shown in the graph, when hydrogen sulfide is generated from the battery cell, the detection value of the monitoring and processing unit 130 changes from 0V to Vcc. 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 greater 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 greater than a threshold.

[0025] Figure 3 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 3 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 reference potential, and the amount of change from the initial value is the difference between the detected value and the reference potential. In particular, when the reference potential is 0V, the amount of change from the initial value matches the detected value. Next, in step S130, the monitoring circuit 100 determines whether the calculated amount of change is greater than a threshold.

[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 perform a process to warn the user 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, according to the hydrogen sulfide detection device 10 described above, the generation of hydrogen sulfide is detected when any one of the multiple exposed metal parts 500 reacts with hydrogen sulfide. In other words, the hydrogen sulfide detection device 10 can detect the generation of hydrogen sulfide at multiple locations within the battery pack by arranging the multiple exposed metal parts 500 at multiple locations within the battery pack. Moreover, the hydrogen sulfide detection device 10 consists of one monitoring circuit 100 and one current path wiring, regardless of the number of detection locations. In particular, this can be achieved by using only one input port of the monitoring processing unit 130 of the monitoring circuit 100. Thus, even if the number of detection locations increases, the hydrogen sulfide detection device 10 can be constructed at low cost and in a small space without complicating the circuit. Furthermore, compared to the case where the detection value between the terminals of the battery cell is used, if the circuit is not electrically connected to the battery cell, the circuit configuration can be simplified and the number of detection locations can be easily increased.

[0029] Furthermore, according to the first embodiment, the exposed metal portion 500 is formed by a pattern 220 on the substrate 200. The pattern 220 on the substrate 200 can be formed to be extremely thin. For example, the pattern 220 can be formed to a thickness of about 50 μm. By forming the exposed metal portion 500 with such a pattern 220, the rate of corrosion when the metal in the exposed metal portion 500 reacts with hydrogen sulfide can be increased. In other words, when hydrogen sulfide is generated from the battery cell, the metal in the exposed metal portion 500 will disappear quickly and break easily. As a result, the detection accuracy of the hydrogen sulfide detection device 10 can be improved. It is also possible to configure the hydrogen sulfide detection device 10 by reusing existing substrates used for monitoring the voltage of battery cells, etc. This makes further cost reduction possible.

[0030] Furthermore, according to the first embodiment, the hydrogen sulfide detection device 10 comprises a plurality of substrates 200, each corresponding to a plurality of exposed metal portions 500. Each of the plurality of exposed metal portions 500 is formed by the pattern 220 of the corresponding substrate 200 among the plurality of substrates 200. In other words, each of the plurality of exposed metal portions 500 is formed by the pattern 220 of a separate substrate 200. The plurality of substrates 200 are connected in a daisy-chain configuration by a cable 300. This allows each of the plurality of exposed metal portions 500 to be individually placed in a desired location within the battery pack. As a result, a hydrogen sulfide detection device 10 with a high degree of freedom in the detection location can be realized.

[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 multiple exposed metal portions 500 may include exposed metal portions 500 that are positioned adjacent to the sealing portion of the battery cell's casing.

[0032] Figure 4 is a conceptual diagram showing an example of the arrangement of the exposed metal portion 500. Figure 4 schematically shows a battery cell 20. When the battery cell 20 is of the laminated type, the casing 21 of the battery cell 20 is typically a laminate film. When the battery cell 20 is of the rectangular type, the casing 21 of the battery cell 20 is typically a metal can. In the example shown in Figure 4, the sealing portion 22 of the casing 21 is located at a position that covers the electrode terminals 23 of the battery cell 20. The substrate 200 is then arranged adjacent to the sealing portion 22 of the casing 21. In this way, the exposed metal portion 500 is arranged adjacent to the sealing portion 22 of the casing 21 of the battery cell 20.

[0033] By positioning the exposed metal portion 500 adjacent to the sealing portion 22 of the battery cell 20's outer casing 21 in this manner, 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 power supply voltage Vcc is directly input to the monitoring and processing unit 130. That is, the monitoring and processing unit 130 acquires the voltage Vcc as the detected value. When hydrogen sulfide is generated from the battery cell, the resistance of the exposed metal part 500 increases, similar to the operation described above, and eventually the circuit breaks. As a result, the detected value of the monitoring and processing unit 130 changes from Vcc to 0V. Therefore, in the modified version as well, 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 process executed by the monitoring circuit 100 at this time may be the same as that shown in Figure 3. In the modified hydrogen sulfide detection device 10, 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.

[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, similar to the first embodiment. On the other hand, compared to the first embodiment, the hydrogen sulfide detection device 10 in the second embodiment includes only one substrate 200. The monitoring circuit 100 and the substrate 200 are directly connected by connectors 110 and 210. In the second embodiment, the pattern 220 on the substrate 200 forms wiring that electrically connects the first node 401 and the second node 402.

[0039] In the second embodiment, the pattern 220 of the substrate 200 forms metal exposed portions 500 at multiple locations where metal is exposed on the surface of the substrate 200. As a result, as shown in Figure 5, the wiring includes multiple metal exposed portions 500.

[0040] The operation of the hydrogen sulfide detection device 10 according to the second embodiment is the same as that of the first embodiment. Therefore, similar to the first embodiment, the hydrogen sulfide detection device 10 according to the second embodiment can detect the generation of hydrogen sulfide at multiple locations within the battery pack by arranging multiple exposed metal parts 500 at multiple locations within the battery pack. Furthermore, similar to the first embodiment, the hydrogen sulfide detection device 10 according to the second embodiment can be constructed in a low-cost and space-saving manner without increasing the complexity of the circuit, even if the number of detection locations increases.

[0041] In the hydrogen sulfide detection device 10 according to the second embodiment, since multiple exposed metal portions 500 are formed on the same substrate 200 pattern 220, the degree of freedom in the detection location is lower compared to the first embodiment. On the other hand, the hydrogen sulfide detection device 10 according to the second embodiment can be constructed from a single substrate 200 and does not require a connecting cable 300, thus reducing costs compared to the first embodiment.

[0042] 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.

[0043] 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, similar to the first embodiment. However, compared to the first embodiment, the hydrogen sulfide detection device 10 in the third embodiment does not include a substrate 200. Instead, both ends of a cable 300 are connected to the connector 110 of the monitoring circuit 100. In the third embodiment, the cable 300 forms wiring that electrically connects the first node 401 and the second node 402.

[0044] In the third embodiment, the metal constituting the cable 300 is a metal that corrodes in reaction with hydrogen sulfide. The cable 300 has multiple metal exposed sections 500 where the metal is exposed to the outside of the cable 300. This can be achieved by stripping the insulation from multiple sections of the cable 300. As a result, as shown in Figure 6, the wiring includes multiple metal exposed sections 500.

[0045] The operation of the hydrogen sulfide detection device 10 according to the third embodiment is the same as that of the first embodiment. Therefore, similar to the first embodiment, the hydrogen sulfide detection device 10 according to the third embodiment can detect the generation of hydrogen sulfide at multiple locations within the battery pack by arranging multiple exposed metal parts 500 at multiple locations within the battery pack. Furthermore, similar to the first embodiment, the hydrogen sulfide detection device 10 according to the third embodiment can be constructed in a low-cost and space-saving manner without increasing the complexity of the circuit, even if the number of detection locations increases.

[0046] In the third embodiment, the hydrogen sulfide detection device 10 cannot form the exposed metal portion 500 as thin as the pattern 220 on the substrate 200, resulting in lower detection accuracy compared to the first embodiment. On the other hand, compared to the first embodiment, the hydrogen sulfide detection device 10 in the third embodiment can be easily constructed with a single cable 300 without requiring the design of the substrate 200. It is also possible to reduce costs. [Explanation of Symbols]

[0047] 10. Hydrogen sulfide detection device 100 Supervisory circuit 200 circuit boards 220 patterns 401 Node 1 402 Node 2 500 Exposed metal parts 20 battery cells 21 Exterior 22 Sealing part

Claims

1. A hydrogen sulfide detection device applied to a battery pack containing a battery cell having a sulfide-based electrolyte, Wiring to electrically connect the first node and the second node, A monitoring circuit that monitors the voltage between the first node and the second node, Equipped with, The aforementioned wiring includes multiple exposed metal portions where metal that corrodes in reaction with hydrogen sulfide is exposed. Hydrogen sulfide detection device.

2. A hydrogen sulfide detection device according to claim 1, The plurality of exposed metal portions are formed by a pattern on at least one substrate. Hydrogen sulfide detection device.

3. A hydrogen sulfide detection device according to claim 2, The at least one substrate includes a plurality of substrates corresponding to each of the plurality of exposed metal portions, Each of the multiple exposed metal portions is formed by the pattern of the corresponding substrate among the multiple substrates. Hydrogen sulfide detection device.

4. A hydrogen sulfide detection device according to claim 1, The plurality of exposed metal portions include exposed metal portions that are positioned adjacent to the sealing portion of the battery cell's outer casing. 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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