Battery system

Abstract

To avoid a situation where a battery system overreacts to a hydrogen sulfide gas from a sulfide-based all-solid battery.SOLUTION: A battery system includes a battery unit 105, a heater unit 121, and a sensor unit 110. The battery unit 105 is housed in a battery case 102 and includes a sulfide-based all-solid battery. The heater unit 121 is configured to heat the battery unit 105. The sensor unit 110 is configured to measure a hydrogen sulfide gas concentration in the battery case 102. Driving of the heater unit 121 is started when a measured value of the sensor unit 110 exceeds a first threshold value. In a case that the measured value exceeds a second threshold value higher than the first threshold value after the driving of the heater unit 121 is started, handling control for handling occurrence of a hydrogen sulfide gas from the sulfide-based all-solid battery is carried out.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 including a secondary battery, a sensor, and a control device. The secondary battery may be a sulfide-based all-solid-state battery housed in a battery case. The sensor is, for example, a hydrogen sulfide concentration meter that detects (measures) the concentration of hydrogen sulfide gas in the battery case. If the detected value of the sensor is higher than a threshold value, the control device determines that hydrogen sulfide is being generated from the secondary battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-46077 Summary of the Invention [Problem to be solved by the invention]

[0004] A sulfide-based all-solid-state battery may generate hydrogen sulfide gas within the battery case. While hydrogen sulfide gas may be present within the battery case, other miscellaneous gases may also be present. When the sensor reacts to the miscellaneous gases, the sensor's measurement error may increase. This may result in the sensor's measurement value exceeding the threshold value even when no hydrogen sulfide is actually being generated from the sulfide-based all-solid-state battery. In this case, it may be erroneously determined that hydrogen sulfide gas is being generated from the sulfide-based all-solid-state battery. As a result, unnecessary control may be executed, potentially resulting in an excessive response to hydrogen sulfide gas from the sulfide-based all-solid-state battery.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to avoid a situation in which excessive hydrogen sulfide gas is generated from a sulfide-based all-solid-state battery. [Means for solving the problem]

[0006] The battery system of the present disclosure includes a battery unit, a heater unit, and a sensor unit. The battery unit is housed in a battery case and includes a sulfide-based all-solid-state battery. The heater unit is configured to heat the battery unit. The sensor unit is configured to measure the concentration of hydrogen sulfide gas inside the battery case. The heater unit is started to operate when a measurement value of the sensor unit exceeds a first threshold value. If the measurement value exceeds a second threshold value higher than the first threshold value after the heater unit starts to operate, response control is executed to respond to the generation of hydrogen sulfide gas from the sulfide-based all-solid-state battery.

[0007] According to the present disclosure, it is possible to avoid a situation in which excessive hydrogen sulfide gas is generated from a sulfide-based all-solid-state battery. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram schematically showing the overall configuration of a vehicle equipped with a battery system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram illustrating each cell of a battery pack of a battery unit. [Figure 3] FIG. 2 is a diagram for explaining the connection relationship between a battery unit, an SMR (System Main Relay), and a drive unit. [Figure 4] FIG. 2 is a perspective view of a battery case and a battery unit. [Figure 5] This is a cross section taken along the line AA in FIG. [Figure 6] 3 is a flowchart illustrating processing and control executed by an ECU (Electronic Control Unit) in the embodiment. [Figure 7] 10 is a flowchart illustrating the processing and control executed by the ECU in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings will be denoted by the same reference numerals, and the description thereof will not be repeated. The embodiments and their modifications may be combined with each other as appropriate.

[0010] 1 is a diagram showing the overall configuration of a vehicle equipped with a battery system according to the present embodiment. The vehicle is, for example, an electric vehicle (BEV), but may also be another type of electrically powered vehicle such as a hybrid vehicle (HEV) equipped with an engine.

[0011] 1, vehicle 1 includes a battery case 102, a battery unit 105, a sensor unit 110, an SMR 112, a drive unit 115, drive wheels 119, a heater unit 121, an HMI (Human Machine Interface) device 122, and an ECU 170. Battery case 102, battery unit 105, sensor unit 110, SMR 112, heater unit 121, HMI device 122, and ECU 170 form a "battery system" of the present disclosure.

[0012] The battery case 102 houses the battery unit 105. The battery unit 105 is configured to be chargeable and dischargeable, and stores power for running the vehicle 1. The battery unit 105 includes a sulfide-based all-solid-state battery. An all-solid-state battery is a battery whose electrolyte layer is solid. A sulfide-based all-solid-state battery is an all-solid-state battery that contains a sulfur component in at least one of the material of the positive electrode active material layer of the battery unit 105 and the material of the solid electrolyte layer of the battery unit 105. The battery unit 105 includes multiple (in this example, two) assembled batteries.

[0013] Fig. 2 is a diagram schematically illustrating each cell of the battery pack of the battery unit 105. Referring to Fig. 2, each cell 52 includes a laminate film 45, an electrode assembly 46, a positive electrode tab 47, and a negative electrode tab 48. The electrode assembly 46 is sealed within the laminate film 45. The positive electrode tab 47 and the negative electrode tab 48 are connected to the electrode assembly 46 and are drawn from the inside to the outside of the laminate film 45. Each cell 52 is a sulfide-based all-solid-state battery.

[0014] Repeated charging and discharging of the battery unit 105 can generate hydrogen sulfide gas within the battery cell 25. For example, gaps may form in the portions where the positive electrode tab 47 and the negative electrode tab 48 are pulled out from the laminate film 45, and air may penetrate into the laminate film 45 through these gaps. As a result, the solid electrolyte layer may react with water in the air, generating hydrogen sulfide gas. Alternatively, an internal short circuit may occur within the electrode body 46, causing the electrode body 46 to heat up and generate hydrogen sulfide gas. In this way, sulfide-based all-solid-state batteries can generate hydrogen sulfide gas themselves. This generation of hydrogen sulfide gas is unique to sulfide-based all-solid-state batteries and is accelerated as the cell temperature rises (the higher the cell temperature, the greater the amount of hydrogen sulfide gas generated).

[0015] 3 is a diagram illustrating the connection relationship between the battery unit 105, the SMR 112, and the drive unit 115. Referring to FIG. 3, the battery unit 105 is configured to be connectable to the drive unit 115 via the SMR 112. Organic solvents may be present outside the battery unit 105. The battery case 102 houses not only the battery unit 105 but also components formed from various chemical materials, including silicone rubber materials.

[0016] The SMR 112 is connected between the battery unit 105 and the drive unit 115. Closing the SMR 112 is equivalent to turning on the driving system of the vehicle 1. Opening the SMR 112 is equivalent to turning off the driving system of the vehicle 1.

[0017] Referring again to FIG. 1, the sensor unit 110 includes sensors 55A and 55B. Each of the sensors 55A and 55B is configured to measure the concentration of hydrogen sulfide (HS) gas within the battery case 102. The measured values ​​of the sensors 55A and 55B are also referred to as measured values ​​MVA and MVB, respectively. Each sensor may also react to gases other than hydrogen sulfide gas (interference gases). That is, each of the measured values ​​MVA and MVB may also be affected by the interference gases.

[0018] The drive unit 115 includes a PCU (Power Control Unit) 116 and a rotating electric machine 118 (see FIG. 3). The PCU 116 is connected to the rotating electric machine 118. The PCU 116 is a power conversion device that converts DC power supplied from the battery unit 105 via the SMR 112 into AC power and supplies the AC power to the rotating electric machine 118. The rotating electric machine 118 is connected to drive wheels 119, receives AC power from the PCU 116, and generates propulsion power (driving power for traveling) for the vehicle 1. The heater unit 121 includes multiple heaters (two in this example) and is configured to heat the battery unit 105.

[0019] The HMI device 122 is a touch screen that receives various operations from the user of the vehicle 1 and functions as a notification device that notifies the user by displaying various screens.

[0020] The ECU 170 includes a processor 171, a memory 172, and a storage device 173. The processor 171 is, for example, a CPU (Central Processing Unit) and executes various types of arithmetic processing. The memory 172 includes a ROM (Read Only Memory) and a RAM (Random Access Memory) (neither of which are shown). The ROM stores programs executed by the processor 171. The storage device 173 stores various types of data.

[0021] The ECU 170 controls various devices of the vehicle 1, such as the SMR 112, the PCU 116, the heater unit 121, the HMI device 122, and an electromagnetic on-off valve (described later). The ECU 170 opens and closes the SMR 112. The ECU 170 controls the charging power and discharging power of the battery unit 105 by controlling the PCU 116. The ECU 150 sets upper limits for the charging power and the discharging power. The ECU 150 can limit the charging power and the discharging power by reducing these upper limits. When the charging power and the discharging power (charging and discharging of the battery unit 105) are limited, the generation of hydrogen sulfide gas is suppressed.

[0022] The ECU 170 determines whether hydrogen sulfide gas is being generated from the battery unit 105 inside the battery case 102, based on the measured values ​​MVA and MVB. For example, if both the measured values ​​MVA and MVB are less than a predetermined threshold value (described later), the ECU 170 determines that hydrogen sulfide gas is not being generated inside the battery case 102. On the other hand, if at least one of the measured values ​​MVA and MVB is equal to or greater than the threshold value, the ECU 170 determines that hydrogen sulfide gas is being generated inside the battery case 102. In this case, the ECU 170 executes response control (described later in detail) to deal with the generation of hydrogen sulfide gas from the battery unit 105.

[0023] Fig. 4 is a perspective view of the battery case 102 and the battery unit 105. Referring to Fig. 4, the battery case 102 houses two assembled batteries 50 (batteries 50A, 50B) included in the battery unit 105. The battery case 102 includes a lower case 91 and an upper case 92. A breathing membrane 61 is provided on the upper case 92.

[0024] The heater unit 121 includes heaters 30A and 30B. The heaters 30A and 30B are disposed below the batteries 50A and 50B, respectively. The heaters 30A and 30B heat the batteries 50A and 50B, respectively.

[0025] The sensors 55A and 55B are respectively disposed near the batteries 50A and 50B. In other words, the sensor 55A is closer to the battery 50A than the sensor 55B, and the sensor 55B is closer to the battery 50B than the sensor 55A.

[0026] Fig. 5 is a cross section taken along line AA in Fig. 4. Referring to Fig. 5, battery pack 50 (battery 50B in this example) includes a plurality of cells 52. Cells 52 and heater 30B are disposed between end plates 31 and 32. Sensor 55B is disposed on the bottom surface of lower case 91. This is because hydrogen sulfide gas is heavier than air.

[0027] The duct 60 is provided in the battery case 102 (upper case 92) and is a communication passage that connects the inside and outside of the battery case 102. Breathable membranes 61 and 62 are provided in the duct 60. Each of the breathable membranes 61 and 62 is made of a breathable and waterproof material. This material is, for example, GORE-TEX (registered trademark). The internal space of the battery case 102 is almost sealed, but is not completely sealed because the breathable membranes 61 and 62 are provided in the duct 60. A desulfurizing agent 63 is disposed inside the duct 60.

[0028] When the pressure inside the battery case 102 increases, air is discharged from the inside of the battery case 102 to the outside through the duct 60 and the breathing membranes 61 and 62. When hydrogen sulfide gas is present inside the battery case 102, the desulfurizing agent 63 adsorbs and purifies the hydrogen sulfide gas traveling from the inside of the battery case 102 to the outside. On the other hand, when the pressure inside the battery case 102 decreases, air flows from the outside of the battery case 102 to the inside through the duct 60 and the breathing membranes 61 and 62.

[0029] Duct 60 is provided with an electromagnetic on-off valve 65. The opening degree of electromagnetic on-off valve 65 is adjusted in accordance with a command from ECU 170. By adjusting this opening degree, duct 60 can be opened or closed. Duct 60 and electromagnetic on-off valve 65 are each included in the battery system described above.

[0030] As described above, the battery unit 105 (sulfide-based all-solid-state battery) may generate hydrogen sulfide gas inside the battery case 102. Although hydrogen sulfide gas may be present inside the battery case 102, miscellaneous gases other than hydrogen sulfide gas may also be present. This is because the air flowing from the outside to the inside of the battery case 102 through the duct 60 contains miscellaneous gases, or miscellaneous gases may be generated from various materials housed inside the battery case 102, organic solvents outside the battery unit 105 (battery assembly 50), or materials constituting the breathing membranes 61 and 62.

[0031] Each of the sensors 55A and 55B may react to miscellaneous gases. In this case, the measurement errors contained in the measured values ​​MVA and MVB may increase. As a result, at least one of the measured values ​​MVA and MVB may exceed the threshold value described above, even though hydrogen sulfide gas is not actually being generated from the battery unit 105. This may result in an erroneous determination that hydrogen sulfide gas is being generated from the battery unit 105. As a result, unnecessary control may be executed, resulting in an excessive response to hydrogen sulfide gas. To avoid the above-mentioned erroneous determination, it may seem preferable to install a high-precision hydrogen sulfide gas concentration sensor in the vehicle 1 that is less sensitive to miscellaneous gases (that can accurately measure only hydrogen sulfide gas). However, this would increase costs.

[0032] In this embodiment, the ECU 170 has a configuration for addressing the above problem. Specifically, the ECU 170 starts driving the heater unit 121 (e.g., both heaters 30A and 30B) when at least one of the measured values ​​MVA and MVB exceeds a first threshold value. After the heater unit 121 starts driving, if neither of the measured values ​​MVA and MVB exceeds a second threshold value, the ECU 170 determines that hydrogen sulfide gas is not being generated from the battery unit 105 in the battery case 102. On the other hand, if at least one of the measured values ​​MVA and MVB exceeds the second threshold value, the ECU 170 determines that hydrogen sulfide gas is being generated from the battery unit 105 in the battery case 102. Based on the result of this determination, the ECU 170 executes response control (described in detail below) to address the generation of hydrogen sulfide gas from the battery unit 105. The second threshold value is higher than the first threshold value.

[0033] With this configuration, if the battery unit 105 is actually generating hydrogen sulfide gas, the generation of hydrogen sulfide gas is accelerated due to heating of the battery unit 105 (increase in cell temperature) after the heater unit 121 starts operating. This increases the amount of hydrogen sulfide gas generated from the battery unit 105, further increasing the hydrogen sulfide gas concentration in the battery case 102. As a result, at least one of the measured values ​​MVA and MVB exceeds the second threshold. On the other hand, the concentration of miscellaneous gases in the battery case 102 is unrelated to the temperature increase of the battery unit 105 and therefore does not increase in response to the start of operation of the heater unit 121. This configuration avoids a false determination that hydrogen sulfide gas is being generated. Furthermore, a high-precision hydrogen sulfide gas concentration sensor is not necessarily required. In addition, it is possible to avoid a situation in which unnecessary response control is initiated due to the reaction of sensors 55A and 55B to miscellaneous gases. Therefore, it is possible to avoid a situation in which excessive response is made to hydrogen sulfide gas from the battery unit 105.

[0034] An example of the corresponding control will be described below. The corresponding control includes at least one of opening the SMR 112 (turning off the driving system), opening the electromagnetic on-off valve 65, controlling the HMI device 122 to notify the user of the generation of hydrogen sulfide gas inside the battery case 102, and controlling the PCU 116 to limit the charging and discharging of the battery unit 105.

[0035] Opening the SMR 112 can disconnect the battery unit 105 from the PCU 116. This electrically isolates the battery unit 105 and cuts off electrical continuity with other components of the vehicle 1. As a result, charging and discharging are stopped (the vehicle 1 is stopped), and the generation of hydrogen sulfide gas is suppressed. Opening the electromagnetic on-off valve 65 allows hydrogen sulfide gas to be discharged from the inside of the battery case 102 to the outside through the duct 60. Controlling the HMI device 122 as described above notifies the user of the generation of hydrogen sulfide gas. This can motivate the user to take measures to deal with the generation of hydrogen sulfide gas (for example, to use a maintenance service for the vehicle 1). Controlling the PCU 116 as described above limits the charging and discharging of the battery unit 105. This suppresses the generation of hydrogen sulfide gas. In this way, the response control can respond to the generation of hydrogen sulfide gas in the battery case 102.

[0036] The first threshold is, for example, 1 ppm or less (1 ppm=0.0001%). The second threshold is, for example, higher than 1 ppm and lower than 5 ppm. In this embodiment, the first threshold is 1 ppm and the second threshold is 3 ppm.

[0037] Generally, the control concentration and allowable concentration of hydrogen sulfide gas are 1 ppm and 5 ppm, respectively. The above configuration prevents the hydrogen sulfide gas concentration from exceeding the allowable concentration (5 ppm) even after at least one of the measured values ​​MVA and MVB exceeds the second threshold value (3 ppm) after the heater unit 121 starts operating. This makes it possible to accurately determine whether hydrogen sulfide gas is being generated or not without the hydrogen sulfide gas concentration exceeding the allowable concentration.

[0038] 6 is a flowchart illustrating the processing and control executed by ECU 170 in this embodiment. This flowchart is started when at least one of the measured values ​​MVA and MVB exceeds a threshold value TH1. Threshold value TH1 corresponds to a first threshold value.

[0039] 6, ECU 170 starts driving heater unit 121 (S110), and then determines whether or not at least one of measurement values ​​MVA and MVB exceeds threshold value TH2 (S115). Threshold value TH2 corresponds to a second threshold value.

[0040] If at least one of the measured values ​​MVA and MVB exceeds the threshold value TH2 (YES in S115), the ECU 170 determines that hydrogen sulfide gas has been generated in the battery case 102 (S120) and executes the corresponding control described above (S125). On the other hand, if neither the measured values ​​MVA nor MVB exceeds the threshold value TH2 (NO in S115), the ECU 170 determines that hydrogen sulfide gas has not been generated in the battery case 102 (S130). In this case, it is considered that the sensor unit 110 has simply reacted to miscellaneous gases. After S125 or S130, the process ends.

[0041] As described above, according to the embodiment, it is possible to accurately determine whether hydrogen sulfide gas is being generated or not. Furthermore, excessive measures against hydrogen sulfide gas from the battery unit 105 can be avoided.

[0042] <Modification of the embodiment> 4, in the embodiment, ECU 170 drives both heaters 30A and 30B, but from the viewpoint of reducing power consumption, only one of these heaters may be driven. In this modification, when measured value MVA exceeds threshold value TH1 earlier than measured value MVB, ECU 170 starts driving only heater 30A of heaters 30A and 30B.

[0043] As described above, sensor 55A is located closer to battery 50A than sensor 55B. Therefore, if the measured value MVA exceeds threshold value TH1 earlier than the measured value MVB, it is considered that hydrogen sulfide gas is being generated from battery 50A, not battery 50B. Therefore, to promote the generation of hydrogen sulfide gas from battery 50A (battery unit 105), it is sufficient to start driving only heater 30A out of heaters 30A and 30B; it is not necessarily necessary to drive both of these heaters. By starting driving only heater 30A as described above, power consumption in heater unit 121 can be reduced compared to an embodiment in which both heaters 30A and 30B are driven. Furthermore, after starting driving heater 30A, the generation of hydrogen sulfide gas from battery 50A is promoted, and the measured value MVA may exceed threshold value TH2. This determines that hydrogen sulfide gas is being generated from battery 50A, and corresponding control is executed.

[0044] 7 is a flowchart illustrating the processing and control in this modified example executed by ECU 170. This flowchart starts when either of the measured values ​​MVA and MVB exceeds threshold value TH1.

[0045] Referring to FIG. 7, ECU 170 determines whether or not measured value MVA exceeded threshold value TH1 earlier than measured value MVB, that is, whether or not the measured value that exceeded threshold value TH1 was measured value MVA (S205).

[0046] If the measured value MVA exceeds threshold value TH1 earlier than the measured value MVB (YES in S205), ECU 170 starts driving heater 30A (S210) and then determines whether or not the measured value MVA exceeds threshold value TH2 (S215). If the measured value MVA does not exceed threshold value TH2 (NO in S215), ECU 170 determines that hydrogen sulfide gas has not been generated in battery case 102 (S230). If the measured value MVA exceeds threshold value TH2 (YES in S215), ECU 170 determines that hydrogen sulfide gas has been generated (S220) and executes corresponding control (S225).

[0047] If the measured value MVB exceeds the threshold value TH1 earlier than the measured value MVA, i.e., if the measured value that exceeds the threshold value TH1 is the measured value MVB (NO in S205), ECU 170 starts driving heater 30B (S212). Next, ECU 170 determines whether the measured value MVB exceeds the threshold value TH2 (S217). If the measured value MVB exceeds the threshold value TH2 (YES in S217), the process proceeds to S220. If the measured value MVB does not exceed the threshold value TH2 (NO in S217), the process proceeds to S230.

[0048] As described above, according to this modification, the power consumption of the heater unit 121 can be reduced.

[0049] <Other variations> Although the sensor unit 110 includes both sensors 55A and 55B, it may include a single sensor that measures the concentration of hydrogen sulfide gas inside the battery case 102 without including these two sensors. In this case, the ECU 170 starts driving the heater unit 121 (e.g., heater 30A) when the measurement value of this sensor exceeds a threshold value TH1. After starting driving the heater unit 121, the ECU 170 determines whether the measurement value exceeds a threshold value TH2. If the measurement value does not exceed the threshold value TH2, the ECU 170 determines that hydrogen sulfide gas has not been generated inside the battery case 102. On the other hand, if the measurement value exceeds the threshold value TH2, the ECU 170 determines that hydrogen sulfide gas has been generated and executes corresponding control.

[0050] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0051] 1 Vehicle, 30A, 30B heater, 50A, 50B battery, 55A, 55B sensor, 65 solenoid valve, 102 battery case, 105 battery unit, 110 sensor unit, 118 rotating electric machine, 121 heater unit, 122 HMI device, 170 ECU.

Claims

1. A battery unit housed in a battery case and including a sulfide-based all-solid-state battery; a heater unit configured to heat the battery unit; a sensor unit configured to measure a hydrogen sulfide gas concentration in the battery case, the heater unit is started to be driven when the measurement value of the sensor unit exceeds a first threshold value; When the measured value exceeds a second threshold value that is higher than the first threshold value after the heater unit starts to operate, a corresponding control is executed to respond to generation of hydrogen sulfide gas from the sulfide-based all-solid-state battery.

2. the battery unit includes a first battery and a second battery; the heater unit includes a first heater that heats the first battery and a second heater that heats the second battery; the sensor unit includes a first sensor and a second sensor each configured to measure the hydrogen sulfide gas concentration, the first sensor being disposed near the first battery and the second sensor being disposed near the second battery; 2. The battery system of claim 1, wherein when the measurement value of the first sensor exceeds the first threshold value earlier than the measurement value of the second sensor, only the first heater of the first heater and the second heater is started to be driven.

3. the battery unit is configured to be chargeable and dischargeable, and is configured to be connectable via a relay device to a power conversion device connected to a rotating electric machine that generates a propulsion force for an electric vehicle; The battery system includes: a communication passage that communicates the inside and the outside of the battery case; an on-off valve provided in the communication passage; and a notification device that notifies a user of the electric vehicle. The corresponding control includes: opening the relay device; Opening the on-off valve; controlling the notification device to notify the user of the generation of the hydrogen sulfide gas in the battery case; 3. The battery system according to claim 1, further comprising at least one of: controlling the power conversion device so as to limit charging and discharging of the battery unit.

4. the first threshold is less than or equal to 1 ppm; The battery system according to claim 1 or 2, wherein the second threshold value is greater than 1 ppm and less than 5 ppm.

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