Battery system

Abstract

A battery system includes a battery unit, a heater unit, and a sensor unit. The battery cell is housed in the 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 a hydrogen sulfide gas concentration within the battery case. The heater unit starts driving when the measured 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 driving, response control for responding to the generation of hydrogen sulfide gas from the sulfide-based all-solid-state battery is executed.

Description

Technical Field

[0001] The present disclosure relates to battery systems. Background Art

[0002] Japanese Patent Application Laid-Open No. 2022-46077 discloses a battery system having 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 housing. The sensor is, for example, a hydrogen sulfide concentration meter that detects (measures) the concentration of hydrogen sulfide gas in the battery housing. When the detection value of the sensor is higher than a threshold value, the control device determines that hydrogen sulfide is generated from the secondary battery. Summary of the invention

[0003] Sulfide-based all-solid-state batteries are capable of generating hydrogen sulfide gas in the battery housing. Hydrogen sulfide gas may exist in the battery housing, but there may also be foreign gases different from hydrogen sulfide gas. If the above-mentioned sensor reacts to foreign gases, the measurement error of the sensor may increase. As a result, even though hydrogen sulfide is not actually generated from the sulfide-based all-solid-state battery, the measurement value of the sensor may exceed the threshold. In this case, it may be mistakenly determined that hydrogen sulfide gas is generated from the sulfide-based all-solid-state battery. As a result, it is possible to perform control that is not originally necessary and excessively deal with hydrogen sulfide gas from the sulfide-based all-solid-state battery.

[0004] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to avoid excessive handling of hydrogen sulfide gas from a sulfide-based all-solid-state battery.

[0005] The battery system disclosed in the present invention comprises a battery cell, a heater unit and a sensor unit. The battery cell is housed in a battery housing and includes a sulfide-based all-solid-state battery. The heater unit is configured to heat the battery cell. The sensor unit is configured to measure the concentration of hydrogen sulfide gas in the battery housing. The heater unit starts to drive when the measured value of the sensor unit exceeds a first threshold value. When the measured value exceeds a second threshold value higher than the first threshold value after the heater unit starts to drive, a response control for responding to the generation of hydrogen sulfide gas from the sulfide-based all-solid-state battery is performed.

[0006] According to the present disclosure, it is possible to avoid excessively dealing with hydrogen sulfide gas from a sulfide-based all-solid-state battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0008] Figure 1 This is a diagram schematically showing the overall structure of a vehicle equipped with a battery system according to the present embodiment.

[0009] Figure 2 The figure schematically shows each cell of a battery pack including a battery cell.

[0010] Figure 3 This is a diagram for explaining the connection relationship between the battery unit, SMR (System Main Relay), and the drive unit.

[0011] Figure 4 It is a three-dimensional diagram of a battery case and a battery cell.

[0012] Figure 5 yes Figure 4 AA section in.

[0013] Figure 6 This is a flowchart illustrating processing and control executed by an ECU (Electronic Control Unit) in the embodiment.

[0014] Figure 7 This is a flowchart for illustrating processing and control executed by the ECU in the modified example. DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals and their description will not be repeated. The embodiments and their modifications may be appropriately combined with each other.

[0016] Figure 1 The figure schematically shows the overall structure of a vehicle equipped with a battery system according to the present embodiment. The vehicle is, for example, a battery electric vehicle (BEV), but may be another type of electric vehicle such as a hybrid electric vehicle (HEV) equipped with an engine.

[0017] Reference Figure 1 The vehicle 1 includes a battery case 102, a battery cell 105, a sensor unit 110, an SMR 112, a drive unit 115, a drive wheel 119, a heater unit 121, an HMI (Human Machine Interface) device 122, and an ECU 170. The battery case 102, the battery cell 105, the sensor unit 110, the SMR 112, the heater unit 121, the HMI device 122, and the ECU 170 form a "battery system" of the present disclosure.

[0018] The battery case 102 accommodates the battery cell 105. The battery cell 105 is configured to be chargeable and dischargeable, and stores power for driving the vehicle 1. The battery cell 105 includes a sulfide-based all-solid-state battery. An all-solid-state battery refers to a battery whose electrolyte layer is solid. A sulfide-based all-solid-state battery is an all-solid-state battery in which at least one of the material of the positive electrode active material layer of the battery cell 105 or the material of the solid electrolyte layer of the battery cell 105 contains a sulfur component. The battery cell 105 includes a plurality of (two in this example) battery packs.

[0019] Figure 2 1 is a diagram schematically showing each unit of the battery pack of the battery unit 105. Figure 2 Each unit 52 includes a laminate film 45, an electrode body 46, a positive electrode tab 47, and a negative electrode tab 48. The electrode body 46 is sealed in the laminate film 45. The positive electrode tab 47 and the negative electrode tab 48 are connected to the electrode body 46 and are led out from the inside of the laminate film 45 to the outside. Each unit 52 is a sulfide-based all-solid-state battery.

[0020] If the battery cell 105 is repeatedly charged and discharged, hydrogen sulfide gas may be generated in the battery cell 25. For example, a gap is formed in the portion where the positive electrode tab 47 and the negative electrode tab 48 are drawn out from the laminate film 45, and air sometimes penetrates into the laminate film 45 from the gap. As a result, the solid electrolyte layer reacts with water in the air and may generate hydrogen sulfide gas. Alternatively, an internal short circuit occurs in the electrode body 46, and the electrode body 46 becomes hot, which may generate hydrogen sulfide gas. In this way, the sulfide-based all-solid-state battery can generate hydrogen sulfide gas from itself. Such generation of hydrogen sulfide gas is unique to sulfide-based all-solid-state batteries, and is promoted as the cell temperature rises (the higher the cell temperature, the more hydrogen sulfide gas is generated).

[0021] Figure 3 1 is a diagram for explaining the connection relationship between the battery unit 105, the SMR 112, and the drive unit 115. Figure 3 The battery cell 105 is configured to be connectable to the drive unit 115 via the SMR 112. An organic solvent may exist outside the battery cell 105. The battery case 102 accommodates, in addition to the battery cell 105, components formed of various chemical materials including a silicone rubber material.

[0022] 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.

[0023] Refer again Figure 1The sensor unit 110 includes sensors 55A and 55B. The sensors 55A and 55B are respectively configured to measure the concentration of hydrogen sulfide (H2S) gas in the battery case 102. The measured values ​​of the sensors 55A and 55B are also respectively represented as measured values ​​MVA and MVB. Each sensor can also react to a gas (contaminant gas) different from hydrogen sulfide gas. That is, the measured values ​​MVA and MVB can also be affected by the contaminant gas.

[0024] The drive unit 115 includes a PCU (Power Control Unit) 116 and a rotary motor 118 (see Figure 3 ). PCU 116 is connected to rotating motor 118. PCU 116 is a power conversion device that converts DC power supplied from battery cell 105 via SMR 112 into AC power and supplies the AC power to rotating motor 118. Rotating motor 118 is connected to drive wheel 119, receives AC power from PCU 116 and generates propulsion force (driving force) for vehicle 1. Heater unit 121 includes a plurality of (two in this example) heaters, and is configured to heat battery cell 105.

[0025] The HMI device 122 is a touch screen, and functions as a notification device that receives various operations from the user of the vehicle 1 or displays various screens to notify the user.

[0026] ECU 170 includes a processor 171, a memory 172, and a storage device 173. Processor 171 is, for example, a CPU (Central Processing Unit), and performs various operations. Memory 172 includes ROM (Read Only Memory) and RAM (Random Access Memory) (neither of which is shown). ROM stores programs executed by processor 171. Storage device 173 stores various data.

[0027] ECU 170 controls various devices of vehicle 1 such as SMR 112, PCU 116, heater unit 121, HMI device 122, and electromagnetic opening and closing valve (described later). ECU 170 opens and closes SMR 112. ECU 170 controls the charging power and discharging power of battery unit 105 by controlling PCU 116. ECU 150 sets the upper limit of charging power and the upper limit of discharging power. ECU 150 can limit the charging power and discharging power respectively by reducing these upper limits. When the charging power and discharging power (charging and discharging of battery unit 105) are limited, the generation of hydrogen sulfide gas is suppressed.

[0028] The ECU 170 determines whether hydrogen sulfide gas is generated from the battery cell 105 in the battery case 102 based on the measured values ​​MVA and MVB. For example, when 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 generated in the battery case 102. On the other hand, when at least one of the measured values ​​MVA and MVB is greater than or equal to the threshold value, the ECU 170 determines that hydrogen sulfide gas is generated in the battery case 102. In this case, the ECU 170 executes a response control for responding to the generation of hydrogen sulfide gas from the battery cell 105 (described later in detail).

[0029] Figure 4 1 is a perspective view of the battery case 102 and the battery cell 105. Figure 4 The battery case 102 accommodates two battery packs 50 (batteries 50A and 50B) included in the battery unit 105. The battery case 102 includes a lower case 91 and an upper case 92. The upper case 92 is provided with a breather membrane 61.

[0030] 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.

[0031] Sensors 55A and 55B are respectively arranged near batteries 50A and 50B. In other words, sensor 55A is closer to battery 50A than sensor 55B, and sensor 55B is closer to battery 50B than sensor 55A.

[0032] Figure 5 for Figure 4 AA section in. Figure 5 The battery pack 50 (in this example, the battery 50B) includes a plurality of cells 52. The plurality of cells 52 and the heater 30B are disposed between the end plates 31, 32. The sensor 55B is disposed on the bottom surface of the lower case 91. This is because hydrogen sulfide gas is heavier than air.

[0033] The duct 60 is provided in the battery housing 102 (upper housing 92) and is a connecting passage that connects the inside and outside of the battery housing 102. Breathing membranes 61 and 62 are provided in the duct 60. The breathing membranes 61 and 62 are respectively made of breathable and waterproof materials. The material is, for example, GORE-TEX (registered trademark). The internal space of the battery housing 102 is generally sealed, but since the breathing membranes 61 and 62 are provided in the duct 60, it is not completely sealed. A desulfurizing agent 63 is arranged inside the duct 60.

[0034] When the pressure inside the battery case 102 rises, 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 exists inside the battery case 102, the desulfurizing agent 63 adsorbs and purifies the hydrogen sulfide gas flowing from the inside of the battery case 102 to the outside. On the other hand, when the pressure inside the battery case 102 drops, air flows from the outside of the battery case 102 to the inside through the duct 60 and the breathing membranes 61 and 62.

[0035] The duct 60 is provided with an electromagnetic on-off valve 65. The opening of the electromagnetic on-off valve 65 is adjusted according to a command from the ECU 170. By adjusting the opening, the duct 60 can be communicated or closed. The duct 60 and the electromagnetic on-off valve 65 are respectively included in the above-mentioned battery system.

[0036] As described above, the battery cell 105 (sulfide-based all-solid-state battery) can generate hydrogen sulfide gas in the battery case 102. Hydrogen sulfide gas may exist in the battery case 102, but there may also be foreign gases different from hydrogen sulfide gas. This is because the air flowing from the outside of the battery case 102 to the inside through the duct 60 contains foreign gases, or foreign gases are generated from various materials contained in the battery case 102, organic solvents outside the battery cell 105 (battery pack 50), or constituent materials of the breathing membranes 61 and 62.

[0037] Sensors 55A and 55B are respectively capable of reacting to foreign gases. In this case, the measurement errors contained in the measured values ​​MVA and MVB may increase. As a result, although hydrogen sulfide gas is not actually generated from the battery cell 105, at least one of the measured values ​​MVA and MVB may exceed the above-mentioned threshold value. Therefore, it may be erroneously determined that hydrogen sulfide gas is generated from the battery cell 105. As a result, it is possible to perform control that is not originally necessary and excessively deal with hydrogen sulfide gas. In order to avoid the above-mentioned misjudgment, it is considered preferable to install a high-precision hydrogen sulfide gas concentration sensor with low reactivity to foreign gases (capable of measuring only hydrogen sulfide gas with high precision) on the vehicle 1. However, this leads to increased costs.

[0038] In the embodiment, ECU 170 has a structure for coping with the above-mentioned problem. Specifically, ECU 170 starts driving heater unit 121 (for example, both heaters 30A and 30B) when at least one of the measured values ​​MVA and MVB exceeds the first threshold value. After the start of driving of heater unit 121, when both the measured values ​​MVA and MVB do not exceed the second threshold value, ECU 170 determines that hydrogen sulfide gas is not generated from battery cell 105 in battery case 102. On the other hand, when at least one of the measured values ​​MVA and MVB exceeds the second threshold value, ECU 170 determines that hydrogen sulfide gas is generated from battery cell 105 in battery case 102. Based on the result of the determination, ECU 170 performs a response control (described in detail later) for coping with the generation of hydrogen sulfide gas from battery cell 105. The second threshold value is higher than the first threshold value.

[0039] By setting such a structure, when the battery cell 105 actually generates hydrogen sulfide gas, after the start of the drive of the heater unit 121, the generation of hydrogen sulfide gas is promoted due to the heating of the battery cell 105 (the increase in the cell temperature). As a result, the amount of hydrogen sulfide gas generated from the battery cell 105 increases, and the concentration of hydrogen sulfide gas in the battery case 102 further increases. As a result, at least one of the measured values ​​MVA and MVB exceeds the second threshold. On the other hand, the concentration of the impurity gas in the battery case 102 has nothing to do with the temperature increase of the battery cell 105, and therefore does not rise in response to the start of the drive of the heater unit 121. According to the above structure, it is possible to avoid the situation where it is erroneously determined that hydrogen sulfide gas is generated. Moreover, a high-precision hydrogen sulfide gas concentration sensor is not necessarily required. In addition, it is possible to avoid the situation where the response control is unnecessarily started due to the reaction of the sensors 55A and 55B to the impurity gas. Therefore, it is possible to avoid the situation where the hydrogen sulfide gas from the battery cell 105 is excessively responded to.

[0040] An example of the response control is described below. The response control includes at least one of the following processes: disconnecting the SMR 112 (turning off the travel system), opening the electromagnetic on-off valve 65, controlling the HMI device 122 to notify the user of the generation of hydrogen sulfide gas in the battery case 102, and controlling the PCU 116 to limit the charge and discharge of the battery cell 105.

[0041] By disconnecting the SMR 112, the battery cell 105 can be disconnected from the PCU 116. As a result, the battery cell 105 is electrically independent and disconnected from the other components of the vehicle 1. As a result, charging and discharging stops (the vehicle 1 stops), and the generation of hydrogen sulfide gas is suppressed. By opening the electromagnetic on-off valve 65, the hydrogen sulfide gas can be discharged from the inside of the battery housing 102 to the outside through the pipe 60. By controlling the HMI device 122 as described above, the user is notified of the generation of hydrogen sulfide gas. Thus, the user can be encouraged to deal with the generation of hydrogen sulfide gas (for example, using the maintenance service of the vehicle 1). By controlling the PCU 116 as described above, the charging and discharging of the battery cell 105 is limited. Thus, the generation of hydrogen sulfide gas is suppressed. In this way, according to the response control, the generation of hydrogen sulfide gas in the battery housing 102 can be dealt with.

[0042] 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 less than 5 ppm. In the embodiment, the first threshold is 1 ppm and the second threshold is 3 ppm.

[0043] Generally, the management concentration and the allowable concentration of hydrogen sulfide gas are 1ppm and 5ppm, respectively. By adopting the above-mentioned structure, even if at least one of the measured values ​​MVA and MVB exceeds the second threshold value (3ppm) after the start of driving of the heater unit 121, it is possible to avoid the situation where the hydrogen sulfide gas concentration exceeds the allowable concentration (5ppm). As a result, it is possible to accurately determine whether hydrogen sulfide gas is generated or not without causing the hydrogen sulfide gas concentration to exceed the allowable concentration.

[0044] Figure 6 1 is a flowchart illustrating processing and control executed by ECU 170 in the embodiment. This flowchart starts when at least one of measurement values ​​MVA and MVB exceeds threshold value TH1. Threshold value TH1 corresponds to the first threshold value.

[0045] Reference Figure 6 ECU 170 starts driving heater unit 121 (S110), and then determines whether at least one of measurement values ​​MVA and MVB exceeds threshold value TH2 (S115). Threshold value TH2 corresponds to the second threshold value.

[0046] When 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 is generated in the battery case 102 (S120), and executes the above-mentioned response control (S125). On the other hand, when neither the measured values ​​MVA nor MVB exceeds the threshold value TH2 (No in S115), the ECU 170 determines that hydrogen sulfide gas is not generated in the battery case 102 (S130). In this case, it is considered that the sensor unit 110 is merely reacting to foreign gas. After S125 or S130, the process ends.

[0047] As described above, according to the embodiment, it is possible to determine with high accuracy whether hydrogen sulfide gas is generated or not, and it is possible to avoid excessive handling of hydrogen sulfide gas from the battery cell 105 .

[0048] <Modification of Implementation>

[0049] Refer again Figure 4 In the embodiment, ECU 170 drives both heaters 30A and 30B, but from the viewpoint of reducing power consumption, only one of the heaters may be driven. In this modified example, ECU 170 starts driving only heater 30A of heaters 30A and 30B when measured value MVA exceeds threshold value TH1 earlier than measured value MVB.

[0050] As described above, the sensor 55A is arranged at a position closer to the battery 50A than the sensor 55B. Therefore, when the measured value MVA exceeds the threshold value TH1 earlier than the measured value MVB, it is considered that the hydrogen sulfide gas is generated from the battery 50A rather than the battery 50B. Therefore, in order to promote the generation of hydrogen sulfide gas from the battery 50A (battery unit 105), it can also be considered that it is sufficient for only the heater 30A to start driving among the heaters 30A and 30B, and it is not necessarily necessary to drive both of these heaters. By starting to drive only the heater 30A as described above, the power consumption in the heater unit 121 can be reduced compared with the embodiment in which both the heaters 30A and 30B are driven. Moreover, after the drive of the heater 30A starts, the generation of hydrogen sulfide gas from the battery 50A is promoted, and the measured value MVA may exceed the threshold value TH2. Therefore, it is determined that the hydrogen sulfide gas is generated from the battery 50A, and the corresponding control is performed.

[0051] Figure 7 1 is a flowchart for illustrating the processing and control executed by ECU 170 in this modification. This flowchart starts when any one of measurement values ​​MVA and MVB exceeds threshold value TH1.

[0052] Reference Figure 7ECU 170 determines whether measurement value MVA exceeds threshold value TH1 earlier than measurement value MVB, that is, whether the measurement value exceeding threshold value TH1 is measurement value MVA ( S205 ).

[0053] When the measured value MVA exceeds the threshold value TH1 earlier than the measured value MVB (Yes in S205), the ECU 170 starts driving the heater 30A (S210), and then determines whether the measured value MVA exceeds the threshold value TH2 (S215). When the measured value MVA does not exceed the threshold value TH2 (No in S215), the ECU 170 determines that hydrogen sulfide gas is not generated in the battery case 102 (S230). When the measured value MVA exceeds the threshold value TH2 (Yes in S215), the ECU 170 determines that hydrogen sulfide gas is generated (S220), and executes the response control (S225).

[0054] When the measured value MVB exceeds the threshold value TH1 earlier than the measured value MVA, that is, when the measured value exceeding the threshold value TH1 is the measured value MVB (No in S205), the ECU 170 starts driving the heater 30B (S212). Next, the ECU 170 determines whether the measured value MVB exceeds the threshold value TH2 (S217). When the measured value MVB exceeds the threshold value TH2 (Yes in S217), the process proceeds to S220. When the measured value MVB does not exceed the threshold value TH2 (No in S217), the process proceeds to S230.

[0055] As described above, according to this modification, the power consumption of the heater unit 121 can be reduced.

[0056] <Other Modifications>

[0057] The sensor unit 110 includes both sensors 55A and 55B, but may include a single sensor for measuring the concentration of hydrogen sulfide gas in the battery case 102 instead of these two sensors. In this case, the ECU 170 starts driving the heater unit 121 (for example, the heater 30A) when the measured value of the sensor exceeds the threshold value TH1. After starting to drive the heater unit 121, the ECU 170 determines whether the measured value exceeds the threshold value TH2. When the measured value does not exceed the threshold value TH2, the ECU 170 determines that hydrogen sulfide gas is not generated in the battery case 102. On the other hand, when the measured value exceeds the threshold value TH2, the ECU 170 determines that hydrogen sulfide gas is generated and executes the response control.

[0058] The embodiments disclosed herein are illustrative in all aspects and should not be construed as restrictive. The scope of the present invention is indicated by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

Claims

1. A battery system comprising: A battery unit, housed in a battery housing, comprising a sulfide-based all-solid-state battery; a heater unit configured to heat the battery cell; and a sensor unit configured to measure the concentration of hydrogen sulfide gas in the battery case, The heater unit starts driving when the measurement value of the sensor unit exceeds a first threshold value, When the measured value exceeds a second threshold value higher than the first threshold value after the heater unit starts driving, response control for responding to generation of hydrogen sulfide gas from the sulfide-based all-solid-state battery is executed.

2. The battery system according to claim 1, wherein: The battery unit includes a first battery and a second battery, The heater unit includes a first heater for heating the first battery and a second heater for heating the second battery, The sensor unit includes a first sensor and a second sensor configured to measure the concentration of the hydrogen sulfide gas, respectively, the first sensor being arranged near the first battery, and the second sensor being arranged near the second battery. 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 starts driving among the first heater and the second heater.

3. The battery system according to claim 1 or 2, wherein: The battery unit is configured to be chargeable and dischargeable, and is configured to be connectable to a power conversion device connected to a rotating electric machine that generates propulsion force for the electric vehicle via a relay device. The battery system further comprises: A communication path for communicating the inside and the outside of the battery housing; an on-off valve, disposed in the communication passage; and a notification device for notifying a user of the electric vehicle, The response control includes at least one of the following processes: disconnecting the relay device; Opening the on-off valve; controlling the notification device to notify the user of the generation of the hydrogen sulfide gas within the battery case; as well as The power conversion device is controlled to limit charging and discharging of the battery unit.

4. The battery system according to claim 1 or 2, wherein: The first threshold is below 1 ppm, The second threshold is higher than 1 ppm and lower than 5 ppm.

Images