Battery System

Abstract

To suppress generation of hydrogen sulfide before the inside of a battery case is filled with a hydrogen sulfide gas.SOLUTION: A cell 10 consists of a sulfide-based all-solid cell. A battery system 100 comprises a battery module 200 in which a plurality of cells 10 is laminated between a pair of end plates 31 and 32. Between the laminated cells 10, an intermediate plate 60 in which a distortion gauge 70 is provided is fixed in a cantilevered state. A control device 300 estimates generation of hydrogen sulfide in the cell 10 based on a change of a load, which is calculated from a detection signal of the distortion gauge 70, applied to the intermediate plate 60.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery system. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2022-46077 (Patent Document 1) discloses a battery system in which a secondary battery using a sulfur-based material for the positive electrode and / or solid electrolyte is cooled by a cooler when the generation of hydrogen sulfide is predicted or detected.

[0003] In Patent Document 1, the generation of hydrogen sulfide gas from a secondary battery is detected by detecting the pressure inside a battery case that houses the secondary battery or the hydrogen sulfide concentration (sulfur concentration) inside the battery case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-46077 Summary of the Invention [Problem to be solved by the invention]

[0005] With the configuration of Patent Document 1, the generation of hydrogen sulfide gas cannot be detected until the hydrogen sulfide gas generated from the secondary battery fills the battery case and the pressure inside the battery case rises or the hydrogen sulfide concentration increases.

[0006] An object of the present disclosure is to make it possible to detect the generation of hydrogen sulfide gas before the battery case is filled with hydrogen sulfide gas. [Means for solving the problem]

[0007] (1) The battery system disclosed herein includes a single cell made of a sulfide-based all-solid-state battery, a battery module in which a plurality of single cells are stacked between a pair of restraining members, an intermediate plate disposed between the stacked single cells, a detection unit that detects a load applied to the intermediate plate, and an estimation unit that estimates the generation of hydrogen sulfide in the single cell based on a change in the load applied to the intermediate plate.

[0008] According to this configuration, the unit cells are sulfide-based all-solid-state batteries. In the present disclosure, a sulfide-based all-solid-state battery is one that contains a sulfur component in at least one of the positive electrode material and the solid electrolyte material. The unit cells are stacked between a pair of restraining members to form a battery module. An intermediate plate is disposed between the stacked unit cells. The detection unit detects the load applied to the intermediate plate. When hydrogen sulfide gas is generated inside the unit cells, the internal pressure of the unit cells increases, and the volume of the unit cells increases. When the volume of the unit cells increases, the load applied to the intermediate plate changes. The estimation unit estimates the generation of hydrogen sulfide in the unit cells based on the change in the load applied to the intermediate plate. Since the generation of hydrogen sulfide in the unit cells is estimated based on the change in the load applied to the intermediate plate, it is possible to detect the generation of hydrogen sulfide before hydrogen sulfide gas fills the battery case.

[0009] (2) The intermediate plate may be fixed in a cantilevered state to the base member to which the restraining member is fixed, and the detection unit may be a strain gauge provided on the intermediate plate.

[0010] With this configuration, the intermediate plate is fixed in a cantilevered manner to the base member to which the restraint member is fixed. Therefore, when hydrogen sulfide gas is generated inside one of the cells and the volume of the cell increases, the load applied to the intermediate plate changes, causing the intermediate plate to deflect around the fixed end as a fulcrum. By detecting this deflection with a strain gauge attached to the intermediate plate, it is possible to estimate the generation of hydrogen sulfide in the cell.

[0011] (3) The intermediate plate may be displaceable in the stacking direction of the unit cells, and the detection unit may be a sensor that detects the displacement of the intermediate plate.

[0012] According to this configuration, the intermediate plate is displaceable in the stacking direction of the cells, so when hydrogen sulfide gas is generated inside one of the cells and the volume of the cell increases, the load applied to the intermediate plate changes, causing the intermediate plate to displace (move) in the stacking direction. By detecting this displacement with a sensor, it is possible to estimate the generation of hydrogen sulfide in the cell.

[0013] (4) The cell may be a laminated all-solid-state battery having a laminate film as an exterior member.

[0014] According to this configuration, the unit cell is a laminated-type all-solid-state battery, and the exterior member is made of a laminate film. Laminate films are more flexible than the metal cases that make up prismatic batteries and the like, and their volume increases relatively easily when the internal pressure of the unit cell increases. Therefore, it is possible to estimate with relatively high accuracy the generation of hydrogen sulfide in the unit cell based on changes in the load applied to the intermediate plate.

[0015] (5) The cell may be an all-solid-state battery containing a sulfide-based solid electrolyte.

[0016] According to this configuration, it is possible to detect that the sulfur component contained in the sulfide-based solid electrolyte reacts with moisture to produce hydrogen sulfide. [Effects of the Invention]

[0017] According to the present disclosure, the generation of hydrogen sulfide can be detected before the battery case is filled with hydrogen sulfide gas. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram schematically showing the overall configuration of a battery system according to an embodiment of the present invention; [Figure 2]1(A) and 1(B) are diagrams illustrating the schematic configuration of a single cell. [Figure 3] 1(A) and 1(B) are diagrams illustrating a method for stacking unit cells. [Figure 4] 4 is a flowchart showing an example of a hydrogen sulfide generation estimation process executed by the control device. [Figure 5] FIG. 10 is a diagram showing a schematic configuration of a battery module according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0020] 1 is a diagram schematically illustrating the overall configuration of a battery system 100 according to the present embodiment. The battery system 100 includes a battery module 200 and a control device 300. The battery module 200 is an assembled battery in which a plurality of unit cells 10 are connected. The unit cells 10 are stacked between a pair of end plates 31, 32.

[0021] Fig. 2 is a diagram illustrating a schematic configuration of a cell 10 according to the present embodiment. Fig. 2(A) is a top view of the cell 10. The cell 10 is a laminated all-solid-state battery that uses a laminate film as an exterior member 20, and a negative electrode terminal (negative electrode tab) 1a and a positive electrode terminal (positive electrode tab) 5a protrude from the exterior member 20. The laminate film may be, for example, a pouch made of aluminum laminate film, or may be a three-layer film having an aluminum foil sandwiched between resin films.

[0022] FIG. 2(B) shows the all-solid-state battery laminate 15 housed in the exterior member 20, and shows the cross section BB of FIG. 2(A). The all-solid-state battery laminate 15 is configured such that three all-solid-state battery elements 8, each of which is composed of an anode current collector layer 1, an anode active material layer 2, a solid electrolyte layer 3, a cathode active material layer 4, and a cathode current collector layer 5 stacked in this order, share the anode current collector layer 1 and the cathode current collector layer 5, and are stacked in reverse order. The anode current collector layer 1 is connected to the anode terminal 1a, and the cathode current collector layer 5 is connected to the cathode terminal 5a. The number of all-solid-state battery elements 8 included in the all-solid-state battery laminate 15 may be one or four or more. The insulating film 7 provides insulation between the all-solid-state battery laminate 15 and the exterior member (laminate film) 20.

[0023] The cell 10 is a sulfide-based all-solid-state battery. In the present disclosure, a sulfide-based all-solid-state battery refers to a battery in which at least one of the material of the positive electrode active material layer 4 and the material of the solid electrolyte layer 3 contains a sulfur component. In this embodiment, the solid electrolyte layer 3 includes a sulfide-based solid electrolyte. For example, the sulfide-based solid electrolyte may be one made from phosphorus pentasulfide (P2S5) or lithium sulfide (Li2S). In this case, the positive electrode active material layer 4 may include, for example, lithium cobalt oxide, lithium nickel oxide, or lithium iron phosphate. When the solid electrolyte layer 3 is made of an oxide-based solid electrolyte, a sulfur-based positive electrode active material is used for the positive electrode active material layer 4. The sulfur-based positive electrode active material may be an organic sulfur compound or an inorganic sulfur compound. Both the solid electrolyte layer 3 and the positive electrode active material layer 4 may contain a sulfur component.

[0024] Referring to FIG. 1, a plurality of unit cells 10 are arranged and stacked between a pair of end plates 31, 32. FIG. 3 is a diagram illustrating a method for stacking the unit cells 10. The unit cells 10 have a flat plate shape, and as shown in FIG. 3(A), the unit cells 10 may be stacked so that the exterior members 20 of the unit cells 10 abut against each other. Alternatively, a plurality of unit cells 10 may be stacked with flat plate-shaped spacers (not shown) interposed between the unit cells 10. Note that, as shown in FIG. 3(B), the unit cells 10 may be covered with a pair of frames 81, 82 having inner surfaces corresponding to the outer shape of the unit cells 10, and the unit cells 10 covered by the pair of frames 81, 82 may be stacked.

[0025] Returning to FIG. 1 , an intermediate plate 60 is disposed between the cells 10 at the center in the stacking direction of the cells 10. The stacked cells 10 and the intermediate plate 60 are sandwiched between a pair of end plates 31, 32, and a predetermined restraining load is applied thereto by, for example, restraining bands 80. The pair of end plates 31, 32 are fixed to the bottom plate 50 by brackets 41, 42. The pair of end plates 31, 32 corresponds to an example of a "pair of restraining members" in the present disclosure.

[0026] In this embodiment, the intermediate plate 60 is fitted and fixed in a groove 51 formed in the bottom plate 50. As a result, the intermediate plate 60 is fixed to the bottom plate 50 in a cantilevered state.

[0027] The intermediate plate 60 is provided with a strain gauge 70. The strain gauge 70 may be a foil-type strain gauge or a semiconductor strain gauge. The strain gauge 70 detects bending strain of the intermediate plate 60.

[0028] A battery module 200, which is made up of cells 10 stacked between a pair of end plates 31, 32, an intermediate plate 60, a bottom plate 50, etc., is fixed to a battery case 90. The battery case 90 is a housing that houses the battery module 200.

[0029] The control device 300 is composed of a processor such as a CPU (Central Processing Unit), memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), input / output ports, etc., and controls the charging and discharging of the battery module 200. In this embodiment, the control device 300 estimates the generation of hydrogen sulfide (HS) in the cells 10 based on the detection signals of the strain gauges 70. The control device 300 functions as the "estimation unit" of the present disclosure.

[0030] 4 is a flowchart showing an example of a hydrogen sulfide generation estimation process executed by the control device 300. This flowchart is repeatedly processed at predetermined intervals. First, in step (hereinafter, step will be abbreviated as "S") 10, the amount of change (load change amount) ΔL in the load L applied to the intermediate plate 60 is acquired based on the detection signal of the strain gauge 70.

[0031] If, for some reason, the sulfur component contained in the solid electrolyte layer 3 or the positive electrode active material layer 4 reacts with water in any of the cells 10 of the battery module 200, generating hydrogen sulfide, the volume of the cell 10 increases due to gas pressure. When the volume of the cell 10 increases, the load applied to the intermediate plate 60 changes. In FIG. 1, if hydrogen sulfide is generated in a cell 10 to the left of the intermediate plate 60, a force Fa is applied to the intermediate plate 60 in the direction indicated by the solid arrow. In FIG. 1, if hydrogen sulfide is generated in a cell 10 to the right of the intermediate plate 60, a force Fb is applied to the intermediate plate 60 in the direction indicated by the dashed arrow.

[0032] When force Fa or force Fb acts on intermediate plate 60, a bending moment is applied to intermediate plate 60, and bending strain is detected by strain gauge 70. In S10, the magnitude of this bending strain is obtained as the load change amount ΔL applied to intermediate plate 60.

[0033] In the next S11, it is determined whether the load change amount ΔL is equal to or greater than a predetermined value A. If the load change amount ΔL is less than the predetermined value A, a negative determination is made and the routine is terminated. If the load change amount ΔL is equal to or greater than the predetermined value A, a positive determination is made and the routine proceeds to S12. The predetermined value A is set in advance by experiment or the like.

[0034] In S12, it is determined that hydrogen sulfide is being generated in the cell 10, and the current routine is terminated. In S12, it is also possible to identify the location of the cell 10 where hydrogen sulfide is being generated by determining whether the bending strain detected by the strain gauge 70 is in the compressive direction or the tensile direction. For example, as shown in FIG. 1 , if the strain gauge 70 is provided on the left surface of the intermediate plate 60, when a force Fa acts on the intermediate plate 60, the strain gauge 70 outputs a detection signal in the tensile direction (extension direction), and when a force Fb acts on the intermediate plate 60, the strain gauge 70 outputs a detection signal in the compressive direction (contraction direction). Therefore, when the detection signal of the strain gauge 70 is in the tensile direction, it can be determined that hydrogen sulfide is being generated in one of the cells 10 to the left of the intermediate plate 60. When the detection signal of the strain gauge 70 is in the compressive direction, it can be determined that hydrogen sulfide is being generated in one of the cells 10 to the right of the intermediate plate 60.

[0035] According to this embodiment, a change in the load applied to the intermediate plate 60 is detected by the bending strain detected by the strain gauge 70 provided on the intermediate plate 60 arranged between the stacked cells 10. Then, the generation of hydrogen sulfide in the cell 10 is estimated based on the change in the load applied to the intermediate plate 60, so that it is possible to detect the generation of hydrogen sulfide in the cell 10 before the battery case 90 becomes filled with hydrogen sulfide.

[0036] In the present embodiment, the pair of end plates 31, 32 and the intermediate plate 60 are fixed to the bottom plate 50. However, the pair of end plates 31, 32 and the intermediate plate 60 may be fixed directly to the battery case 90.

[0037] (Variation) 5 is a diagram showing a schematic configuration of a battery module 200a according to a modified example. In the battery module 200a, an intermediate plate 61 located in the center of the stacked cells 10 is not fixed to the bottom plate 55. This allows the intermediate plate 61 to be displaced (moved) in the stacking direction of the cells 10. A displacement sensor (displacement meter) 71 is provided on the bottom plate 55 at a portion facing the intermediate plate 61. The displacement sensor 71 may be a variable resistance displacement sensor whose resistance changes depending on the displacement of the intermediate plate 61, or may be a non-contact linear displacement sensor using the Hall effect.

[0038] In the modified example, generation of hydrogen sulfide in the battery 10 is also estimated by the process shown in the flowchart of Fig. 4. In the modified example, in S10, the amount of change (load change amount) ΔL in the load L applied to the intermediate plate 61 is acquired based on the detection signal of the displacement sensor 71.

[0039] If, for some reason, the sulfur component contained in the solid electrolyte layer 3 or the positive electrode active material layer 4 reacts with water in any of the cells 10 of the battery module 200, generating hydrogen sulfide, the volume of the cell 10 increases due to gas pressure. When the volume of the cell 10 increases, the load applied to the intermediate plate 61 changes. In FIG. 5, when hydrogen sulfide is generated in the cell 10 to the left of the intermediate plate 61, a force Fa is applied to the intermediate plate 61 in the direction indicated by the solid arrow. In FIG. 5, when hydrogen sulfide is generated in the cell 10 to the right of the intermediate plate 61, a force Fb is applied to the intermediate plate 61 in the direction indicated by the dashed arrow.

[0040] When force Fa or force Fb acts on the intermediate plate 61, the intermediate plate 61 is displaced in the stacking direction of the cells 10, and the displacement of the intermediate plate 61 is detected by the displacement sensor 71. In S10, the magnitude of this displacement is acquired as the load change amount ΔL applied to the intermediate plate 60. The processes in S11 and S12 are the same as those in the above embodiment.

[0041] In S12, it is also possible to identify the location of the cell 10 where hydrogen sulfide is being generated, based on the direction of displacement detected by the displacement sensor 71. For example, when a force Fa acts on the intermediate plate 61 and the intermediate plate 61 is displaced to the right in FIG. 5, it can be determined that hydrogen sulfide is being generated in one of the cells 10 to the left of the intermediate plate 61. Furthermore, when a force Fb acts on the intermediate plate 61 and the intermediate plate 61 is displaced to the left in FIG. 5, it can be determined that hydrogen sulfide is being generated in one of the cells 10 to the right of the intermediate plate 61.

[0042] In this modified example, a change in the load applied to the intermediate plate 61 is detected by the displacement detected by the displacement sensor 71 that detects the displacement of the intermediate plate 61 disposed between the stacked cells 10. Then, the generation of hydrogen sulfide in the cells 10 is estimated based on the change in the load applied to the intermediate plate 61, so that it is possible to detect the generation of hydrogen sulfide in the cells 10 before the battery case 90 becomes filled with hydrogen sulfide.

[0043] In the above embodiment and modified examples, the intermediate plate 60 equipped with the strain gauge 70, or the combination of the intermediate plate 61 and the displacement sensor 71, is provided in the center of the stacking direction of the cells 10. However, the position of these is not limited to the center. A plurality of intermediate plates 60, or a combination of the intermediate plate 61 and the displacement sensor 71, may be arranged, for example, at equal intervals. Furthermore, the intermediate plate 60 equipped with the strain gauge 70 and the combination of the intermediate plate 61 and the displacement sensor 71 may be provided at intervals in one battery module.

[0044] The battery system 100 may be mounted on an electric vehicle or may be stationary.

[0045] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0046] 1 negative electrode current collector layer, 2 negative electrode active material layer, 3 solid electrolyte layer, 4 positive electrode active material layer, 5 positive electrode current collector layer, 7 insulating film, 8 all-solid-state battery element, 10 single cell, 15 all-solid-state battery laminate, 20 exterior member, 31, 32 end plate, 41, 42 bracket, 50, 55 bottom plate, 60, 61 intermediate plate, 70 strain gauge, 71 displacement sensor, 80 restraining band, 81, 82 frame pair, 90 battery case, 100 battery system, 200, 200a battery module, 300 control device.

Claims

1. a single cell consisting of a sulfide-based all-solid-state battery; a battery module in which a plurality of the unit cells are stacked between a pair of restraining members; an intermediate plate disposed between the stacked cells; a detection unit that detects a load applied to the intermediate plate; an estimation unit that estimates generation of hydrogen sulfide in the battery cell based on a change in the load applied to the intermediate plate.

2. the intermediate plate is fixed in a cantilevered state to a base member to which the restraining member is fixed, The battery system according to claim 1 , wherein the detection unit is a strain gauge provided on the intermediate plate.

3. the intermediate plate is displaceable in a stacking direction of the unit cells, The battery system according to claim 1 , wherein the detection unit is a sensor that detects displacement of the intermediate plate.

4. The battery system according to claim 1 , wherein the single cells are laminated all-solid-state batteries having a laminate film as an exterior member.

5. The battery system according to claim 4 , wherein the single cell includes a sulfide-based solid electrolyte.

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