Power storage device and method for detecting sulfuration gas

Abstract

Provided are a power storage device and a method of detecting a sulfuration gas. A battery pack includes a battery module including a single cell including a solid electrolyte layer; a battery case that houses the battery module; an absorber disposed inside the battery case and that absorbs a sulfuration gas; a sensor portion that measures an electrical characteristic of the absorber; and a calculation unit that detects the sulfuration gas absorbed by the absorber based on the electrical characteristic measured by the sensor portion.

Description

Technical Field

[0001] This disclosure relates to methods for detecting energy storage devices and sulfuric gases. Background Technology

[0002] Japanese Patent Application Publication No. 2025-19541 discloses a battery pack that determines gas generation based on the voltage of wiring corroded by gas generated from a single cell. Summary of the Invention

[0003] In the battery pack described in Japanese Patent Application Publication No. 2025-19541, it is conceivable that corrosion of the wiring will not progress when the amount of gas generated is small. In this case, it may be impossible to detect that gas has been generated.

[0004] This disclosure is made to solve the above-mentioned problems, and its purpose is to provide an energy storage device that can easily identify the generation of sulfur gas and a method for detecting sulfur gas.

[0005] The energy storage device of the first aspect of this disclosure includes: an energy storage module having an energy storage unit comprising a sulfide solid electrolyte; a housing housing the energy storage module; an absorber disposed within the housing and absorbing sulfide gas; a measuring unit measuring the electrical characteristics of the absorber; and a control unit detecting the sulfide gas absorbed by the absorber based on the electrical characteristics measured by the measuring unit.

[0006] In the energy storage device of the first aspect of this disclosure, as described above, sulfide gas is detected based on the electrical characteristics of an absorber capable of absorbing sulfide gas. Here, it is easier to allow the absorber capable of absorbing sulfide gas to absorb the gas than, for example, to cause corrosion of wiring or the like by sulfide gas. Therefore, compared to detecting sulfide gas based on corrosion of wiring or the like, the generation of sulfide gas can be easily determined based on the electrical characteristics of the absorber.

[0007] The absorber can also be hygroscopic. With this configuration, the absorber can absorb the sulfide aqueous solution formed by condensation produced when sulfide gas dissolves in the shell.

[0008] The casing may also include a base plate with recesses. The absorber may also be disposed in the recesses. Here, since sulfide gas is heavier than air, it tends to move towards the base plate side within the casing. Additionally, the aqueous sulfide solution formed by dissolving sulfide gas in condensate water moves towards the base plate side within the casing due to its own weight. Therefore, by arranging the absorber in the recesses formed in the base plate, the absorber can absorb more sulfide gas.

[0009] The absorber can also be located below the battery module. This structure allows the absorber to easily absorb sulfide gases that have moved below the battery module.

[0010] The absorbent can also be formed into a gel. Therefore, unlike when the absorbent is liquid, it can prevent the absorbent from scattering due to vibration, etc. This prevents the absorbent containing sulfide gases from scattering into the shell, thus inhibiting corrosion inside the shell.

[0011] The casing can also have a sealed structure. This structure prevents water from entering the casing from the outside. Consequently, it prevents water entering from the outside from being absorbed by the absorber. This, in turn, prevents the detection of sulfide gases from becoming inappropriate due to water entering from the outside.

[0012] The energy storage device may also include a gas detection unit for detecting sulfur gas inside the casing. With this structure, sulfur gas can be detected not only by the control unit but also by the gas detection unit. Therefore, for example, if the control unit malfunctions in detecting sulfur gas, the generation of sulfur gas can be determined based on the detection results of the gas detection unit.

[0013] The absorber has an upper end, a lower end, and a central portion between the upper and lower ends, and a measuring portion is disposed in the absorber on the upper end side of the central portion. With this structure, the electrical characteristics of the portion of the absorber on the upper end side of the central portion can be measured by the measuring portion.

[0014] The measuring unit may also include a substrate disposed within the housing. The absorber may also cover two specific points on the substrate. The measuring unit can also measure the potential difference between the two points covered by the absorber. The control unit can also calculate the resistance value between the two points based on the potential difference, and detect the sulfide gas absorbed by the absorber based on the resistance value. With this structure, the generation of sulfide gas can be easily determined based on the resistance value between the two points.

[0015] In this case, the control unit can also determine that the absorber is in a first state when the resistance value is less than a predetermined threshold, and determine that the absorber is in a second state different from the first state when the resistance value is above the predetermined threshold. Based on this structure, by using the predetermined threshold, the state of the absorber can be distinguished into a first state and a second state for identification.

[0016] Alternatively, the first state could include a state where the absorber has absorbed both moisture and sulfide gas, and the second state could include a state where the absorber has absorbed moisture but not sulfide gas. This structure allows for easy differentiation and identification of whether the absorber contains sulfide gas.

[0017] The second aspect of this disclosure describes a method for detecting sulfide gas, which is performed by an energy storage device having an energy storage module, the energy storage module including an energy storage unit containing a sulfide solid electrolyte. The method for detecting sulfide gas includes the following steps: measuring the electrical characteristics of an absorber disposed within a housing housing the energy storage module and absorbing sulfide gas; and detecting the sulfide gas absorbed by the absorber based on the electrical characteristics.

[0018] In the method for detecting sulfide gases according to the second aspect of this disclosure, as described above, the sulfide gases are detected based on the electrical properties of the absorber that absorbs the sulfide gases. Therefore, a method for detecting sulfide gases that allows for easy identification of the generated sulfide gases based on the electrical properties of the absorber can be provided.

[0019] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description in relation to the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a diagram showing the structure of the vehicle and battery pack according to this embodiment.

[0021] Figure 2 It is along Figure 1 A sectional view along line II-II.

[0022] Figure 3 This is a top view showing the structure of a single cell.

[0023] Figure 4 It is along Figure 3 A cross-sectional view along line IV-IV.

[0024] Figure 5 This is a schematic three-dimensional diagram showing the structure of the inner side of the battery casing.

[0025] Figure 6 It is along Figure 5 A sectional view along line VI-VI.

[0026] Figure 7 This is a flowchart illustrating a method for detecting hydrogen sulfide performed by a battery pack.

[0027] Figure 8 This is a cross-sectional view showing the structure of the absorber in the first modified example of this embodiment.

[0028] Figure 9 This is a cross-sectional view showing the structure of the absorber in the second modified example of this embodiment. Detailed Implementation

[0029] Embodiments of this disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings referred to below, the same or equivalent parts are labeled with the same reference numerals.

[0030] Figure 1 This is a diagram that roughly shows the overall structure of the vehicle 200 equipped with the battery pack 100. Additionally, Figure 1 The X, Y, and Z directions shown are mutually orthogonal. For example, the X and Y directions can also be the width and front-rear directions of the vehicle 200, respectively, when the battery pack 100 is mounted on the vehicle 200. The X1 and X2 directions can also be the left and right sides of the vehicle, respectively. The Y1 and Y2 directions can also be the front and rear of the vehicle, respectively. In addition, the Z direction can also be the vertical direction. Furthermore, the battery pack 100 is an example of the "energy storage device" disclosed herein.

[0031] The vehicle 200 includes a battery pack 100 for storing electricity used for driving. The vehicle 200 is configured to use the electricity stored in the battery pack 100 for driving. In this embodiment, the vehicle 200 is described as an electric vehicle (BEV) without an engine (internal combustion engine), but the vehicle 200 could also be a hybrid electric vehicle (HEV) with an engine or a plug-in hybrid electric vehicle (PHEV). Furthermore, the application of the battery pack 100 is not limited to vehicle applications.

[0032] Vehicle 200 includes a control unit (ECU: Electronic Control Unit) 150. ECU 150 is configured to perform charging and discharging control of battery pack 100. ECU 150 includes a processor 151, RAM (Random Access Memory) 152, a storage unit 153, and a communication unit 154. RAM 152 functions as a working memory for temporarily storing data processed by processor 151. Storage unit 153 stores, in addition to the program, information used in the program (e.g., mappings, mathematical formulas, and various parameters). Processor 151 executes the program stored in storage unit 153 to perform various controls within ECU 150 (charging and discharging control of battery pack 100, and communication control using communication unit 154). Communication unit 154 is configured to perform wireless communication with an external terminal (not shown) using a predetermined communication method.

[0033] In addition, the battery pack 100 is charged by regenerative power from the driving drive unit 110 described later, or by power supplied from a charging device outside the vehicle 200 (external charging).

[0034] The vehicle 200 also includes a drive unit 110, an HMI (Human Machine Interface) device 120, and drive wheels W. The drive unit 110 includes a PCU (Power Control Unit) and an MG (Motor Generator), not shown, configured to use electricity stored in the battery pack 100 to drive the MG, thus enabling the vehicle 200 to move. Additionally, the MG is configured to perform regenerative power generation, supplying the generated electricity to the battery pack 100.

[0035] HMI device 120 includes an input device and a display device. HMI device 120 may also include a touch panel display.

[0036] The battery pack 100 includes a plurality of (two in this embodiment) battery modules 10 and a battery housing 20. The plurality of battery modules 10 are respectively housed in the battery housing 20. The plurality of battery modules 10 are arranged in an X-direction. The battery housing 20 is formed of metal (e.g., aluminum). Furthermore, the battery housing 20 is an example of a "housing" according to this disclosure. Additionally, the battery modules 10 are an example of a "energy storage module" according to this disclosure.

[0037] The battery housing 20 is composed of a lower housing 21 and an upper housing 22. In this embodiment, two battery modules 10 are housed in the space formed by the lower housing 21 and the upper housing 22. The battery pack 100 is mounted on the floor of the vehicle 200. Alternatively, the battery pack 100 can be mounted inside the vehicle 200 or outside the vehicle 200.

[0038] The battery housing 20 has a sealed structure. The battery pack 100 includes a breather valve 90. The breather valve 90 is located in the battery housing 20. For example, the breather valve 90 is located in the upper housing 22. The breather valve 90 adjusts the pressure inside the battery housing 20 by allowing gas (air) to pass through. For example, the breather valve 90 adjusts the pressure inside the battery housing 20 when the internal pressure of the battery housing 20 decreases due to condensation inside the battery housing 20. Furthermore, the location of the breather valve 90 is not limited to the example described above.

[0039] Figure 2 This is a diagram showing the general structure of the battery pack 100. Figure 2 The middle shows Figure 1 Section II-II is shown in the diagram. The battery module 10 is a battery pack connecting multiple individual cells 11. The multiple individual cells 11 are stacked along the Y direction between a pair of end plates 12 and 13. The multiple individual cells 11 are sandwiched between the pair of end plates 12 and 13 in a stacked state, and a predetermined constraint load is applied by constraint straps (not shown) or the like. Furthermore, the individual cell 11 is an example of an "energy storage unit" of this disclosure.

[0040] A pair of end plates 12 and 13 are fixed to the base plate 16 via brackets 31 and 32. The battery module 10, comprising a single battery 11 stacked between the pair of end plates 12 and 13 and the base plate 16, is fixed to the base plate 23 of the lower housing 21. The battery housing 20 is a box (shell) that houses the battery module 10.

[0041] A hydrogen sulfide sensor 40 is disposed inside the battery casing 20. The hydrogen sulfide sensor 40 is a sensor that detects the concentration C of hydrogen sulfide (H2S) in the environment (air within the battery pack 100), and outputs a voltage signal indicating the detection result to the ECU 150. Figure 1 Furthermore, the hydrogen sulfide sensor 40 is an example of the "gas detection unit" of this disclosure. Additionally, hydrogen sulfide is an example of the "sulfiding gas" of this disclosure.

[0042] In this embodiment, the hydrogen sulfide sensor 40 is located on or near the top plate 22a of the upper housing 22. Therefore, the hydrogen sulfide emitted from the single cell 11 towards the Z1 side can be easily detected by the hydrogen sulfide sensor 40. Furthermore, the placement of the hydrogen sulfide sensor 40 is not limited to the example described above. For example, the hydrogen sulfide sensor 40 may also be located on the bottom plate 23 of the lower housing 21.

[0043] Figure 3 This is a top view illustrating the schematic structure of the single cell 11 in this embodiment. The single cell 11 is a laminated all-solid-state battery that uses a laminated film as the outer casing 14, with the negative terminal (negative electrode tab) 11a and the positive terminal (positive electrode tab) 11b protruding from the outer casing 14. The laminated film can be, for example, a bag made of aluminum laminated film, or a three-layer film consisting of aluminum foil sandwiched between resin films. Alternatively, a metal can may be used instead of the laminated film as the outer casing 14.

[0044] Figure 4 It is an all-solid-state battery stack 15 housed in the external component 14, showing Figure 3The IV-IV cross section. In the all-solid-state battery stack 15, the all-solid-state battery element 8, which is formed by sequentially stacking a negative electrode current collector layer 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector layer 5, has a total of three negative electrode current collector layers 1 and positive electrode current collector layers 5, with the stacking order set in opposite directions. The negative electrode current collector layer 1 is connected to the negative terminal 11a, and the positive electrode current collector layer 5 is connected to the positive terminal 11b. In addition, the all-solid-state battery stack 15 may contain one or more all-solid-state battery elements 8. The insulating film 7 insulates the all-solid-state battery stack 15 from the outer component 14 (laminated film). In addition, the single cell 11 may not be a stacked type as described above, but a wound type formed by overlapping and winding the negative electrode current collector layer, negative electrode active material layer, solid electrolyte layer, positive electrode active material layer, and positive electrode current collector layer. In addition, the solid electrolyte layer 3 is an example of the "sulfide solid electrolyte" disclosed herein.

[0045] The single cell 11 is a sulfide-based all-solid-state battery. In this disclosure, a sulfide-based all-solid-state battery refers to a battery in which at least one of the materials of the negative electrode active material layer 2, the positive electrode active material layer 4, or the solid electrolyte layer 3 contains a sulfur component. In this embodiment, the solid electrolyte layer 3 comprises a sulfide-based solid electrolyte, for example, a sulfide-based solid electrolyte may be based on phosphorus pentasulfide (P2S5) or lithium sulfide (Li2S) as starting materials. In this case, the positive electrode active material layer 4 may, for example, comprise lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, etc. When the solid electrolyte layer 3 is composed of an oxide-based solid electrolyte, a sulfur-based positive electrode active material can be used as the positive electrode active material layer 4. The sulfur-based positive electrode active material can be an organic sulfur compound or an inorganic sulfur compound. Furthermore, two or all of the negative electrode active material layer 2, the positive electrode active material layer 4, and the solid electrolyte layer 3 may contain a sulfur component (sulfide-based solid electrolyte).

[0046] In the single cell 11, for example, air may enter from the sealed portion of the outer component 14 (laminated film). When the invading air contains moisture, the moisture may react with the sulfur components contained in the solid electrolyte layer 3, the negative electrode active material layer 2, or the positive electrode active material layer 4 to produce hydrogen sulfide, which is then released into the battery casing 20.

[0047] Figure 5 This is a schematic perspective view showing the internal structure of the battery casing 20. Figure 5 For simplicity, the diagrams of wiring 74, 75 and absorber 60, which will be described later, are omitted.

[0048] The battery pack 100 includes an arithmetic unit 50. The arithmetic unit 50 is disposed within the battery housing 20. The arithmetic unit 50 is a monitoring IC that monitors the voltage, etc., of each battery module 10. Alternatively, the arithmetic unit 50 may be disposed outside the battery housing 20. Furthermore, the arithmetic unit 50 is an example of the "control unit" of this disclosure.

[0049] A recess 24 is formed in the bottom plate 23 of the lower housing 21. The recess 24 is located near the arithmetic unit 50. Figure 5 In the example shown, the recess 24 is formed on the Y2 side of the arithmetic unit 50 at a position adjacent to the arithmetic unit 50.

[0050] Figure 6 This is a cross-section of the recess 24 along the X direction, shown. Figure 5 VI-VI section.

[0051] The battery pack 100 includes an absorber 60 and a sensor 70. The absorber 60 and the sensor 70 are disposed within the battery housing 20. Furthermore, the sensor 70 is an example of the "measuring unit" of this disclosure.

[0052] The absorber 60 absorbs hydrogen sulfide. Specifically, the absorber 60 absorbs (absorbs moisture) hydrogen sulfide water 80 formed by dissolving hydrogen sulfide (gas) in condensation water within the battery casing 20. Alternatively, the absorber 60 may also directly absorb hydrogen sulfide (gas) within the battery casing 20. Furthermore, the hydrogen sulfide water 80 is an example of the "sulfide aqueous solution" disclosed herein.

[0053] The absorber 60 can also be formed from, for example, glycerol. Glycerol is a polymer resin with high acid resistance. Therefore, it is possible to prevent the absorber 60 from deteriorating due to absorption of sulfide aqueous solution.

[0054] The sensor unit 70 measures the electrical characteristics of the absorber 60. Specifically, the sensor unit 70 measures the potential difference between two points in the absorber 60. The sensor unit 70 is disposed inside the absorber 60. The method for measuring the potential difference by the sensor unit 70 will be described later.

[0055] In the case of conventional battery packs that detect the generation of gas from a single cell based on the corrosion of wiring, for example, if the amount of gas generated is small, the corrosion of the wiring may not progress, making it impossible to detect the generation of gas.

[0056] Therefore, in this embodiment, the arithmetic unit 50 detects the hydrogen sulfide (hydrogen sulfide water) absorbed by the absorber 60 based on the electrical characteristics of the absorber 60 measured by the sensor unit 70. Specifically, the arithmetic unit 50 detects the hydrogen sulfide absorbed by the absorber 60 by detecting a decrease in the resistance value of the absorber 60 due to the absorption of hydrogen sulfide. The arithmetic unit 50 can also calculate the concentration of hydrogen sulfide relative to the water absorbed by the absorber 60.

[0057] Therefore, unlike methods that detect the generation of gas from a single cell based on factors such as the corrosion of wiring, hydrogen sulfide can be detected easily and quickly without waiting for the wiring to corrode.

[0058] The absorbent 60 is formed into a gel-like state (the state in which a colloidal solution solidifies into a gel). That is, the absorbent 60 is viscous. In addition, the absorbent 60 has water-absorbing and moisture-retaining properties.

[0059] The recess 24 is defined by a bottom surface 24a and a peripheral surface 24b. The peripheral surface 24b extends from the outer periphery of the bottom surface 24a toward the Z1 side. The peripheral surface 24b extends downward from the bottom surface 23a of the lower housing 21 where the battery module 10 and the arithmetic unit 50 are disposed. That is, the recess 24 is formed at the lowest position within the battery housing 20. With this configuration, moisture such as condensation inside the battery housing 20 flows into the lowest recess 24 in the battery housing 20 when the vehicle 200 is in motion. In addition, the bottom surface 23a is the inner surface of the battery housing 20 within the base plate 23.

[0060] The bottom surface 24a extends orthogonally to the Z direction. The peripheral surface 24b includes side surfaces 24c and 24d facing each other in the X direction. Side surface 24c slopes towards side surface 24d as it approaches the bottom surface 23a of the base plate 23. Side surface 24d slopes towards side surface 24c as it approaches the bottom surface 24a of the recess 24. Although not shown in the figure, the side surfaces in the peripheral surface 24b that appear in the Y direction are formed in the same manner as side surfaces 24c and 24d.

[0061] An absorber 60 is disposed in the recess 24. Specifically, the absorber 60 contacts the bottom surface 24a and the peripheral surface 24b of the recess 24, respectively. More specifically, the absorber 60 has a lower end surface 61, an upper end surface 62, and an outer peripheral surface 63. The lower end surface 61 contacts the bottom surface 24a. The outer peripheral surface 63 contacts the peripheral surface 24b. The outer peripheral surface 63 extends downward from the periphery of the upper end surface 62. Additionally, the outer peripheral surface 63 extends upward from the periphery of the lower end surface 61. The outer peripheral surface 63 connects the upper end surface 62 and the lower end surface 61. Furthermore, the lower end surface 61 and the upper end surface 62 are examples of the "lower end portion" and "upper end portion" of this disclosure, respectively.

[0062] The absorber 60 is located below the battery module 10. Specifically, the upper end face 62 of the absorber 60 is located below the bottom surface 23a of the lower housing 21 (base plate 23). That is, a space without the absorber 60 is formed near the opening of the recess 24. With this structure, condensation inside the battery housing 20 can easily flow into the recess 24. In addition, the entire space of the recess 24 can be filled with the absorber 60.

[0063] The sensor unit 70 includes a printed circuit board 71. The printed circuit board 71 has a substrate body 71a, an electrode 72, and an electrode 73. The electrode 72 is connected to the arithmetic unit 50 via a wiring 74. The electrode 73 is connected to the arithmetic unit 50 via a wiring 75. Furthermore, the electrode 72 and electrode 73 are not electrically connected via the substrate body 71a. The printed circuit board 71 is an example of a "substrate" according to this disclosure.

[0064] Specifically, electrode 72 is electrically connected to the positive terminal of power supply 51 within the arithmetic unit 50 via wiring 74. Electrode 73 is electrically connected to the negative terminal of power supply 51 within the arithmetic unit 50 via wiring 75. A current sensor 52 is configured in the current path between power supply 51 and wiring 75. Power supply 51 may, for example, be the same power supply used for monitoring the state of battery module 10.

[0065] A printed circuit board 71 is disposed in the recess 24. Specifically, the printed circuit board 71 is disposed inside the absorber 60. That is, the substrate body 71a and electrodes 72 and 73 are completely shielded from the outside air by the absorber 60. The absorber 60 covers the gap V between electrodes 72 and 73. In other words, the gap V is filled by the absorber 60. Electrodes 72 and 73 are electrically connected through the portion of the absorber 60 that fills the gap V. In addition, the gap V is an example of "between specific two points" in this disclosure.

[0066] The printed circuit board 71 (substrate body 71a) measures the potential difference ΔV between electrode 72 and electrode 73. The printed circuit board 71 (substrate body 71a) sends the measured potential difference ΔV information to the arithmetic unit 50. The printed circuit board 71 (substrate body 71a) communicates with the arithmetic unit 50 via wired or wireless means (not shown).

[0067] The arithmetic unit 50 calculates the resistance value R between the electrode 72 and the electrode 73 based on the potential difference ΔV received from the printed circuit board 71 and the detection value A of the current sensor 52. The resistance value R is calculated using the following formula (1).

[0068] R=ΔV / A…(1)

[0069] The resistance value R calculated by the arithmetic unit 50 is based on the resistance value of a portion of the absorber 60 located in the gap V between electrodes 72 and 73. For example, the resistance value R may also be equal to the resistance value of the portion of the absorber 60 located in the gap V. Based on the calculated resistance value R, the arithmetic unit 50 determines whether the absorber 60 has absorbed hydrogen sulfide. Details are explained in the flowchart below.

[0070] Additionally, the absorber 60 has a central portion 64 between its upper end face 62 and lower end face 61. Figure 6 In the diagram, a dashed line is drawn at position P in the Z direction of the central portion 64. The sensor portion 70 (printed substrate 71) is disposed in the portion 65 of the absorber 60 that is above the end face 62 (Z1 side) of the central portion 64.

[0071] Here, hydrogen sulfide water has a lower specific gravity than water. Therefore, when absorber 60 absorbs both hydrogen sulfide water and water, the hydrogen sulfide water tends to remain in the absorber 60 at a higher position than the water. Therefore, by placing the sensor 70 in the portion 65 of the absorber 60 above the end face 62 of the central portion 64, changes in the electrical properties (resistance value) of the absorber 60 caused by hydrogen sulfide water can be easily detected.

[0072] (Methods for detecting hydrogen sulfide)

[0073] Figure 7 This is a flowchart illustrating the hydrogen sulfide detection method performed by the battery pack 100. Figure 7 The control process can also be executed at predetermined intervals (e.g., every 5 minutes). In addition, the processing of steps S1 to S6 is performed by the battery pack 100, and the processing of steps S7 and S8 is performed by the ECU 150 and the HMI device 120, respectively.

[0074] In step S1, the potential difference ΔV between electrode 72 and electrode 73 is measured by the printed substrate 71 (substrate body 71a).

[0075] In step S2, the resistance value R between electrode 72 and electrode 73 is calculated by the arithmetic unit 50 using the potential difference ΔV measured in step S1 and the above formula (1).

[0076] In step S3, the arithmetic unit 50 determines whether the resistance value R calculated in step S2 is less than a predetermined threshold Rth. If the resistance value R is less than the threshold Rth (yes in S3), the process proceeds to step S4. If the resistance value R is greater than or equal to the threshold Rth (no in S3), the process proceeds to step S5. Furthermore, the threshold Rth is an example of a "predetermined threshold" in this disclosure.

[0077] In step S4, the processing unit 50 determines that the absorber 60 is in a first state. Here, the threshold Rth is the resistance value of the absorber 60 under conditions where the absorber 60 has absorbed a certain amount of hydrogen sulfide and moisture, which is determined in advance through experiments or simulations. Therefore, the first state includes the state where the absorber 60 has absorbed hydrogen sulfide and moisture. Next, the process proceeds to step S6. Alternatively, the threshold Rth can also be, for example, about 80% of the initial resistance value of the absorber 60.

[0078] In step S5, the processing unit 50 determines that the absorber 60 is in the second state. The second state includes a state where the absorber 60 has absorbed moisture but has not absorbed hydrogen sulfide. Then, the process ends.

[0079] In step S6, the arithmetic unit 50 sends data to the ECU 150 ( Figure 1 The ECU 150 sends a signal indicating an abnormality in the environment inside the battery casing 20. Then, the process ends. Additionally, upon receiving the aforementioned signal, the ECU 150 sends a signal to the HMI device 120. Figure 1 Send signals to report anomalies.

[0080] Furthermore, even when the absorber 60 absorbs a large amount of moisture but not hydrogen sulfide, the resistance value R may sometimes be lower than the threshold Rth. That is, the first state described above also includes the state where the absorber 60 absorbs a large amount of moisture but not hydrogen sulfide. Even in this case, since an abnormal signal indicating an anomaly is sent to the ECU 150 in step S6, the abnormal state of a large amount of moisture in the battery housing 20 can be reported to the user of the vehicle 200. In other words, by using the absorber 60, not only the generation of hydrogen sulfide can be detected, but also the generation of a large amount of condensation. Therefore, compared to the case where separate sensor units are provided for detecting hydrogen sulfide and sensor units for detecting the generation of a large amount of condensation are provided, the number of parts can be reduced, and the structure of the battery pack 100 can be simplified.

[0081] In step S7, ECU150 ( Figure 1 The system sends a signal to the HMI device 120 to report an anomaly in the environment inside the battery housing 20 to the user. In step S8, the HMI device 120 may also, based on the signal received in step S7, cause the vehicle navigation device to display a message indicating the anomaly, or report the anomaly via a speaker.

[0082] As described above, in this embodiment, the arithmetic unit 50 detects hydrogen sulfide absorbed by the absorber 60 based on the resistance value of the absorber 60 measured by the sensor unit 70. Therefore, compared to, for example, corroding wiring with hydrogen sulfide, absorbing hydrogen sulfide by the absorber 60 can be performed easily and quickly. Thus, compared to detecting hydrogen sulfide by detecting the voltage value of wiring corroded by hydrogen sulfide, hydrogen sulfide can be detected more easily and quickly.

[0083] Furthermore, even if hydrogen sulfide is not detected by the hydrogen sulfide sensor 40 due to the small amount of hydrogen sulfide produced from the single cell 11 (the amount produced per unit time) because hydrogen sulfide is dissolved in the condensate, hydrogen sulfide can still be detected with high sensitivity based on the resistance value of the absorber 60.

[0084] Furthermore, in this embodiment, the absorber 60 is hygroscopic. Therefore, the absorber 60 can absorb hydrogen sulfide water formed by dissolving hydrogen sulfide in the condensation water within the battery casing 20. As a result, even if the concentration of hydrogen sulfide in the battery casing 20 decreases due to absorption by the condensation water, the generation of hydrogen sulfide can be easily determined based on the resistance value of the absorber 60 that has absorbed the hydrogen sulfide water.

[0085] (Modified Example)

[0086] In the above embodiments, an example is shown of calculating the resistance value of the absorber 60 based on the potential difference between the two electrodes and detecting hydrogen sulfide based on the resistance value, but this disclosure is not limited thereto. Hydrogen sulfide may also be detected based solely on the potential difference between the two electrodes. For example, an acidity sensor (pH sensor) may be used to determine the pH between the two electrodes based on the potential difference between them, and hydrogen sulfide may be detected based on the measured pH.

[0087] In the above embodiments, an example is shown where the printed circuit board 71 and the arithmetic unit 50 are connected by a wire, but this disclosure is not limited thereto. The printed circuit board 71 and the arithmetic unit 50 can also communicate wirelessly.

[0088] In the above embodiment, an example of the absorber 60 being disposed in the recess 24 is shown, but the present disclosure is not limited thereto. The absorber 60 may also be disposed in a location other than the recess 24 (e.g., the bottom surface 23a of the lower housing 21).

[0089] In the above embodiments, an example of the absorber 60 being formed in a gel-like (solid) state is shown, but this disclosure is not limited thereto. For example, the absorber 60 may also be a liquid.

[0090] In the above embodiments, an example is shown where the battery pack 100 includes a hydrogen sulfide sensor 40 for detecting hydrogen sulfide, but this disclosure is not limited thereto. The hydrogen sulfide sensor 40 may also be omitted from the battery pack.

[0091] In the above embodiments, an example is shown where the printed circuit board 71 is entirely disposed inside the absorber 60, but this disclosure is not limited thereto. As long as the electrodes 72 and 73 are electrically connected through the absorber 60, a portion of the electrodes 72 and 73 and the substrate body 71a may also be disposed outside the absorber 60. Alternatively, the printed circuit board 71 (substrate body 71a) may not be used. For example, only the two electrodes may be inserted into the absorber 60.

[0092] In the above embodiment, an example is shown where the sensor portion 70 (printed substrate 71) is positioned above the upper end face 62 of the central portion 64 of the absorber 60, but this disclosure is not limited thereto. The sensor portion 70 (printed substrate 71) may also be positioned at the central portion 64 or below the lower end face 61 of the central portion 64.

[0093] For example, such as Figure 8 As shown, the absorber 160 and the bottom surface 24a of the recess 24 can also be separated. The printed circuit board 71 is disposed in the space between the absorber 160 and the bottom surface 24a. Furthermore, at least a portion of each of the electrodes 72 and 73 is covered by the absorber 160. Thus, the electrodes 72 and 73 are electrically connected through the absorber 160. Additionally, in Figure 8 In the example shown, the absorber 160 is supported from below by a support portion 161 provided in the recess 24. The support portion 161 may also be formed in a ring shape.

[0094] In addition, such as Figure 9 As shown, a portion of the substrate body 71a and electrodes 72 and 73 can also be disposed outward from the upper end surface 62 of the absorber 60. Figure 9 As shown, the substrate body 71a can also be disposed entirely outside the absorber 60 by positioning the substrate body 71a above the electrodes 72 and 73.

[0095] In the above embodiments, an example is shown of determining whether the absorber 60 is in a first state or a second state based on the resistance value R of the absorber 60, but this disclosure is not limited thereto. For example, it is also possible to determine that the absorber 60 is in a third state (a completely dry state) where it has not absorbed hydrogen sulfide water and moisture. For example, it is also possible to determine that the absorber 60 is in a third state when the resistance value R is below a predetermined value smaller than the threshold Rth.

[0096] In addition, the above-mentioned variations can also be implemented by appropriately combining all or part of them.

[0097] Embodiments of the present invention have been described, but should be considered as illustrative rather than restrictive in all respects. The scope of the invention is defined by the claims and is intended to include all modifications within the meaning and scope of the claims.

Claims

1. An energy storage device, comprising: The energy storage module has an energy storage unit containing a sulfide solid electrolyte; A housing that accommodates the energy storage module; An absorber is disposed within the housing and absorbs sulfide gases; The measuring unit measures the electrical properties of the absorber; and The control unit detects the sulfide gas absorbed by the absorber based on the electrical characteristics measured by the measuring unit.

2. The energy storage device according to claim 1, wherein, The absorbent is hygroscopic.

3. The energy storage device according to claim 1 or 2, wherein, The housing includes a bottom plate with recesses. The absorber is disposed in the recess.

4. The energy storage device according to claim 1 or 2, wherein, The absorber is located below the energy storage module.

5. The energy storage device according to claim 1 or 2, wherein, The absorber forms a gel-like structure.

6. The energy storage device according to claim 1 or 2, wherein, The shell has a sealed structure.

7. The energy storage device according to claim 1 or 2, wherein, The energy storage device also includes a gas detection unit for detecting sulfide gas inside the casing.

8. The energy storage device according to claim 1 or 2, wherein, The absorber has: an upper end, a lower end, and a central portion between the upper end and the lower end. The measuring part is disposed in the absorber at the upper end side, which is closer to the central part.

9. The energy storage device according to claim 1 or 2, wherein, The measuring unit includes a substrate disposed within the housing. The absorber covers the area between two specific points in the substrate. The measuring unit measures the potential difference between the two points covered by the absorber. The control unit calculates the resistance value between the two points based on the potential difference, and detects the sulfide gas absorbed by the absorber based on the resistance value.

10. The energy storage device according to claim 9, wherein, The control unit determines that the absorber is in a first state when the resistance value is less than a predetermined threshold, and determines that the absorber is in a second state different from the first state when the resistance value is above the predetermined threshold.

11. The energy storage device according to claim 10, wherein, The first state includes the state in which the absorber absorbs moisture and sulfide gas. The second state includes the state in which the absorber absorbs moisture but does not absorb sulfur gas.

12. A method for detecting sulfide gas, performed by an energy storage device equipped with an energy storage module, the energy storage module comprising an energy storage unit, the energy storage unit comprising a sulfide solid electrolyte. The method for detecting sulfide gases comprises the following steps: The electrical properties of the absorber, which is disposed within a housing housing the energy storage module and absorbs sulfide gas, are measured; and The sulfide gas absorbed by the absorber is detected based on the electrical properties.

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