All-solid-state battery system, vehicle equipped with same, and method for controlling all-solid-state battery

Abstract

To prevent occurrence of inconvenience caused by reaction unevenness after restart of charging of an all-solid-state battery.SOLUTION: A vehicle 1 on which an all-solid-state battery system is mounted includes a battery 21 that is an all-solid-state battery, an electric heater 22 that heats the battery 21, and an ECU 100 that controls the electric heater 22. When charging of the battery 21 is resumed after interruption of less than a predetermined time, the ECU 100 increases the temperature of the battery 21 after resumption of charging to be higher than the temperature of the battery 21 before interruption of charging by controlling the electric heater 22.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an all-solid-state battery system, a vehicle including the same, and a control method for an all-solid-state battery. [Background technology]

[0002] In recent years, research and development of all-solid-state batteries has been progressing with the aim of installing them in vehicles. For example, a control device for an all-solid-state battery disclosed in Japanese Patent Laid-Open Publication No. 2019-132696 (Patent Document 1) is configured to estimate the state of charge (SOC) of the all-solid-state battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-132696 Summary of the Invention [Problem to be solved by the invention]

[0004] In general, all-solid-state batteries are more susceptible to reaction unevenness in the thickness direction of the negative electrode than liquid-state batteries. When reaction unevenness occurs in an all-solid-state battery, the overvoltage caused by the reaction unevenness increases, resulting in an increase in the voltage of the all-solid-state battery.

[0005] The present inventors have noticed that reaction irregularities can be particularly pronounced when charging of an all-solid-state battery is resumed after an interruption of less than a predetermined time. If the voltage of the all-solid-state battery increases due to reaction irregularities, various problems may occur after charging is resumed. For example, lithium ions may precipitate as lithium metal on the surface of the negative electrode. Alternatively, the voltage may reach a predetermined full-charge determination voltage and charging may end even though the all-solid-state battery has not actually reached full charge. It is desirable to prevent such problems caused by reaction irregularities.

[0006] The present disclosure has been made to solve the above problems, and one of the purposes of the present disclosure is to prevent inconveniences caused by uneven reactions after resuming charging of an all-solid-state battery. [Means for solving the problem]

[0007] (1) An all-solid-state battery system according to a first aspect of the present disclosure includes an all-solid-state battery, a heating device for heating the all-solid-state battery, and a control device for controlling the heating device. When charging of the all-solid-state battery is resumed after an interruption of less than a predetermined time, the control device controls the heating device to raise the temperature of the all-solid-state battery after resuming charging above the temperature of the all-solid-state battery before interruption of charging.

[0008] (2) The all-solid-state battery includes an active material, and the predetermined time is the time required for uneven reaction occurring in the active material to be resolved.

[0009] In the above configurations (1) and (2), when charging of the all-solid-state battery is resumed after an interruption of less than a predetermined time, the heating device is controlled so that the temperature of the all-solid-state battery increases after charging is resumed. This promotes mitigation of reaction irregularities and reduces overvoltage caused by reaction irregularities. By reducing the overvoltage, the voltage rise of the all-solid-state battery can be made gentler. Therefore, the above configurations (1) and (2) can prevent problems caused by reaction irregularities.

[0010] (3) The all-solid-state battery system further includes a voltage sensor that detects the voltage of the all-solid-state battery. When the detected value of the voltage sensor after resuming charging exceeds a reference voltage, the control device controls the heating device to lower the temperature of the all-solid-state battery after the detected value of the voltage sensor has exceeded the reference voltage below the temperature of the all-solid-state battery before the detected value of the voltage sensor exceeded the reference voltage.

[0011] (4) The all-solid-state battery system further includes a temperature sensor for detecting a temperature of the all-solid-state battery. The control device sets the reference voltage lower as the detected value of the temperature sensor decreases.

[0012] (5) The control device sets the reference voltage higher as the SOC of the all-solid-state battery increases.

[0013] In the configuration (3) above, the heating device is controlled so that the temperature of the all-solid-state battery decreases after the detected value of the voltage sensor exceeds the reference voltage. This ensures that the heating time required to promote the mitigation of reaction irregularities and reduce overvoltage is sufficient (in other words, it prevents unnecessary heating after the reaction irregularities have been sufficiently mitigated and the overvoltage has become small). Furthermore, as will be described in detail later, the configurations (4) and (5) above allow the heating time by the heating device to be adjusted to an appropriate length by appropriately setting the reference voltage.

[0014] (6) If, after resuming charging, the elapsed time since charging was interrupted exceeds a reference time, the control device controls the heating device to lower the temperature of the all-solid-state battery after the elapsed time exceeds the reference time below the temperature of the all-solid-state battery before the elapsed time exceeds the reference time.

[0015] (7) The reference time is shorter than the predetermined time.

[0016] (8) The reference time is the remaining time obtained by subtracting the time during which charging was interrupted from the predetermined time.

[0017] (9) The all-solid-state battery system further includes a temperature sensor for detecting a temperature of the all-solid-state battery. The control device sets the reference time to be longer as the detected value of the temperature sensor becomes lower.

[0018] In the configuration (6) above, when the elapsed time since charging was interrupted exceeds a reference time, the heating device is controlled so as to lower the temperature of the all-solid-state battery. This ensures that the heating time required to promote the mitigation of reaction irregularities and reduce overvoltage is secured. Furthermore, according to the configurations (7) to (9) above, by appropriately setting the reference time, the heating time by the heating device can be adjusted to an appropriate length.

[0019] (10) A vehicle according to a second aspect of the present disclosure includes the above-described all-solid-state battery system.

[0020] (11) A control method for an all-solid-state battery according to a third aspect of the present disclosure includes the steps of: charging the all-solid-state battery; and, when the charging is resumed after an interruption of less than a predetermined time, heating the all-solid-state battery so that the temperature of the all-solid-state battery after the charging is resumed is higher than the temperature of the all-solid-state battery before the charging was interrupted.

[0021] According to the configuration (10) and the method (11), similarly to the configuration (1), it is possible to prevent the occurrence of problems caused by uneven reaction. [Effects of the Invention]

[0022] According to the present disclosure, it is possible to prevent inconveniences caused by uneven reactions after resuming charging of an all-solid-state battery. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram illustrating an example of an overall configuration of a vehicle according to a first embodiment of the present disclosure. [Figure 2] FIG. 10 is a diagram for explaining voltage components of a battery related to a temperature increase process. [Figure 3] 4 is a time chart for explaining a method of adjusting a target temperature in a temperature increase process according to the first embodiment. [Figure 4] 4 is a flowchart showing a processing procedure for a temperature increase process according to the first embodiment. [Figure 5] FIG. 4 is a conceptual diagram showing an example of a map used to set a reference voltage. [Figure 6] 10 is a time chart for explaining a method of adjusting a target temperature in a temperature increase process according to the second embodiment. [Figure 7] 10 is a flowchart showing a processing procedure for a temperature increase process according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] 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.

[0025] In the following, an example will be described in which the all-solid-state battery system according to the present disclosure is mounted on a vehicle, but the use of the all-solid-state battery system according to the present disclosure is not limited to vehicle use, and may be other uses such as stationary use.

[0026] [Embodiment 1] <Vehicle configuration> FIG. 1 is a diagram illustrating an example of the overall configuration of a vehicle according to a first embodiment of the present disclosure. Vehicle 1 is configured to be capable of external charging using power supplied from an external power source (such as a charging station) not shown. In this example, external charging is plug-in charging. However, external charging may also be contactless charging. In this example, vehicle 1 is a battery electric vehicle (BEV). Vehicle 1 may also be another type of vehicle, such as a plug-in hybrid electric vehicle (PHEV).

[0027] The vehicle 1 includes a charging unit 10, a battery pack 20, a drive unit 30, drive wheels 40, and an ECU (Electronic Control Unit) 100. The charging unit 10 includes an inlet 11, a DC / DC converter 12, and a charge relay (CHR) 13. The battery pack 20 includes a battery 21, an electric heater 22, a voltage sensor 23, a current sensor 24, and a temperature sensor 25. The drive unit 30 includes a PCU (Power Control Unit) 31 and a motor generator 32.

[0028] The inlet 11 is configured to receive a charging connector (not shown) of a charging cable via mechanical connection such as fitting, etc. The inlet 11 receives power supplied from an external power supply.

[0029] DC / DC converter 12 is electrically connected between inlet 11 and charging relay 13. DC / DC converter 12 drops the voltage of the DC power supplied from an external power supply via inlet 11 in accordance with a control command from ECU 100. Note that an AC / DC converter (not shown) for normal charging may be provided instead of or in addition to DC / DC converter 12 for rapid charging.

[0030] The charging relay 13 is electrically connected between the DC / DC converter 12 and the battery 21. The charging relay 13 is opened / closed in response to a control command from the ECU 100. When the charging relay 13 is closed, power can be transmitted between the inlet 11 and the battery 21.

[0031] The battery 21 is an assembled battery including a plurality of cells (typically tens to hundreds). Each cell is an all-solid-state battery. As the all-solid-state battery, batteries using various known materials such as those containing a sulfide-based solid electrolyte or an oxide-based solid electrolyte can be used. The battery 21 stores power for driving the motor generator 32 and supplies the power to the motor generator 32 via the PCU 31. The battery 21 is also charged by receiving regenerative power via the PCU 31 during regenerative power generation by the motor generator 32.

[0032] The electric heater 22 is, for example, a PTC (Positive Temperature Coefficient) heater. In a low-temperature environment, the electric heater 22 heats the battery 21 using power supplied from an external power source during plug-in charging. However, the electric heater 22 may also be operated using power supplied from the battery 21. The electric heater 22 is an example of a "heating device" according to the present disclosure.

[0033] The voltage sensor 23 detects the temperature (battery voltage VB) of the battery 21. The current sensor 24 detects the current IB input to and output from the battery 21. The temperature sensor 25 detects the temperature (battery temperature TB) of the battery 21. Each sensor outputs the detection result to the ECU 100.

[0034] The PCU 31 is configured to perform bidirectional power conversion between the battery 21 and the motor generator 32 in accordance with a control command from the ECU 100.

[0035] The motor generator 32 is an AC rotating electric machine, such as a three-phase AC synchronous motor with a permanent magnet embedded in the rotor. The motor generator 32 mainly operates as an electric motor, receiving electric power from the battery 21 to rotate and drive the drive wheels 40. On the other hand, when the vehicle 1 is decelerating (during braking, traveling downhill, etc.), the motor generator 32 operates as a generator to generate regenerative electricity. The electric power generated by the motor generator 32 is charged into the battery 21 via the PCU 31.

[0036] The ECU 100 includes a processor 101, a memory 102, and a storage 103. The processor 101 is an arithmetic device such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The memory 102 is a volatile memory (working memory) such as a RAM (Random Access Memory). The storage 103 is a rewritable non-volatile memory such as a flash memory. The storage 103 stores a system program including an OS (Operating System) and a control program including computer-readable code required for control calculations. The processor 101 reads the system program and the control program, loads them into the memory 102, and executes them to perform various processes. The ECU 100 corresponds to a "control device" according to the present disclosure. The ECU 100 may be divided into multiple ECUs for each function.

[0037] In this embodiment, the main processing executed by the ECU 100 is a temperature increase process for the battery 21. In this example, the temperature increase process is a process of operating the electric heater 22 so that the battery temperature TB (the value detected by the temperature sensor 25) approaches a target temperature. The ECU 100 operates the electric heater 22 until the battery temperature TB reaches the target temperature (or falls within a predetermined temperature range including the target temperature). When the battery temperature TB reaches the target temperature, the ECU 100 stops the electric heater 22. When the battery temperature TB falls below the target temperature (or the lower limit of the predetermined range), the ECU 100 operates the electric heater 22 again.

[0038] <Uneven reaction> 2 is a diagram for explaining voltage components of the battery 21 related to the temperature increase process. The battery voltage VB detected by the voltage sensor 23 is the CCV (Closed Circuit Voltage) of the battery 21, and is higher than the OCV (Open Circuit Voltage). The difference between the battery voltage VB and the OCV may contain various components. Part of this difference is overvoltage caused by uneven reaction occurring in the all-solid-state battery.

[0039] Generally, in a secondary battery, the charging reaction proceeds more easily in the thickness direction of the negative electrode closer to the positive electrode, and the charging reaction proceeds less easily in the thickness direction of the negative electrode farther from the positive electrode. Therefore, reaction unevenness (charging unevenness) may occur in the thickness direction of the negative electrode. In an all-solid-state battery that does not contain an electrolyte solution, reaction unevenness may be more pronounced than in a lithium-ion battery (liquid-based battery) that contains an electrolyte solution. This is because in an all-solid-state battery that does not contain an electrolyte solution, it is difficult to form ion conduction paths between solid electrolytes in the thickness direction, and the resistance associated with the movement of lithium ions in the thickness direction is high. Therefore, in the battery 21, which is an all-solid-state battery, overvoltage due to reaction unevenness is likely to increase, and as a result, the battery voltage VB is likely to increase.

[0040] The inventors of the present invention have noticed that reaction irregularities can be particularly pronounced when charging of an all-solid-state battery is resumed after an interruption of less than a predetermined time. More specifically, during charging, lithium ions migrate from the positive electrode through the solid electrolyte layer to the negative electrode. It is known that lithium ions migrate (conduct) primarily via a hopping mechanism within the solid electrolyte layer of an all-solid-state battery during charging (lithium ion hopping conduction). This occurs when lithium ions enter the active material on the negative electrode surface, resulting in a chain reaction of lithium ions. During the interruption of charging, no new lithium ions are supplied to the active material on the negative electrode surface, preventing this chain reaction of lithium ions. Therefore, the state in which lithium ions are abundant in the active material on the negative electrode surface (i.e., reaction irregularities) prior to the interruption of charging tends to be maintained. While reaction irregularities can be alleviated by the electrolyte in liquid-based batteries, they are not alleviated by the electrolyte in all-solid-state batteries. Therefore, reaction irregularities may remain when charging is resumed after an interruption of less than a predetermined time.

[0041] If the battery voltage VB rises due to an overvoltage caused by an uneven reaction, various problems may occur after plug-in charging is resumed. For example, lithium ions may precipitate as lithium metal on the surface of the negative electrode (lithium deposition). Alternatively, even if the battery 21 is not actually fully charged, the battery voltage VB may reach a predetermined full-charge determination voltage, causing plug-in charging to end. It is desirable to prevent such problems from occurring.

[0042] Therefore, in this embodiment, when plug-in charging is resumed after an interruption of less than a predetermined time, the ECU 100 raises the target temperature for the temperature-raising process of the battery 21. As a result, after plug-in charging is resumed, the battery temperature TB rises compared to before the plug-in charging was interrupted. Generally, when the temperature of a lithium-ion battery rises, the resistance associated with the movement of lithium ions decreases. Therefore, when the battery temperature TB rises, the mitigation of reaction irregularities is promoted, and overvoltage decreases. This reduces the battery voltage VB that rose while plug-in charging was interrupted. As a result, it is possible to prevent problems caused by reaction irregularities.

[0043] <Target temperature adjustment> 3 is a time chart for explaining a method of adjusting a target temperature in the temperature increase process according to the first embodiment. The horizontal axis represents elapsed time. The vertical axis represents whether or not plug-in charging (power supply) is performed and the target temperature of the battery 21. The same applies to FIG. 6, which will be described later.

[0044] In this example, at the initial time, the vehicle 1 is being plugged in for charging. stomach Therefore, it is desirable to raise the temperature of the battery 21 during plug-in charging. In this case, the target temperature of the battery 21 is set to TAG1. TAG1 is a temperature at which the increase in internal resistance due to low temperatures is sufficiently small (negligible), and is typically room temperature (for example, 25°C).

[0045] Plug-in charging is interrupted at time t11 and resumed at time t12. The reasons for interrupting and resuming plug-in charging are not particularly limited. One example is when the user interrupts plug-in charging to leave in vehicle 1, but the departure is postponed. Another example is when a temporary power outage occurs and then the power supply is restored. The interruption time ΔT of plug-in charging is assumed to be short enough to be called a short break (for example, on the order of several tens of seconds to several minutes).

[0046] The target temperature of the battery 21 after plug-in charging resumes at time t12 is set to TAG2. TAG2 is higher than TAG1 and is a high temperature that can promote mitigation of reaction unevenness. The higher the temperature of the battery 21, the more the mitigation of reaction unevenness is promoted. On the other hand, if the temperature of the battery 21 becomes excessively high, the charging power to the battery 21 may reach the control upper limit value Win, and charging to the battery 21 may be suppressed. Therefore, TAG2 is typically a temperature that is higher than room temperature and within a temperature range (for example, a temperature range of 35°C to 60°C) in which charging is not suppressed by the control upper limit value Win.

[0047] At time t13, a voltage condition is established that indicates that the reaction unevenness has been sufficiently alleviated (i.e., eliminated). More specifically, when the reaction unevenness is eliminated, the overvoltage is reduced, and the battery voltage VB drops. Therefore, it can be determined that the reaction unevenness has been eliminated when the battery voltage VB becomes equal to or lower than the reference voltage Vref. When the battery voltage VB becomes equal to or lower than the reference voltage Vref, in this embodiment, the target temperature of the battery 21 is set to TAG1 again.

[0048] Thereafter, at time t14, the plug-in charging ends, and the temperature increase process also ends.

[0049] In the example shown in Fig. 3, the target temperature when the reaction unevenness is resolved after plug-in charging is resumed is equal to the target temperature (=TAG1) before plug-in charging was interrupted. However, these two target temperatures may be different. The former target temperature can be set to any temperature as long as it is lower than the target temperature (=TAG2) from the time when the reaction unevenness is resolved after plug-in charging is resumed.

[0050] <Processing flow> 4 is a flowchart showing the procedure of the temperature increase process according to the first embodiment. The process shown in this flowchart is executed when a predetermined condition is met (for example, at each control period). As described above, it is assumed that the battery temperature TB is low and heating of the battery 21 has started.

[0051] Each step is realized by software processing by the ECU 100, but may also be realized by hardware (electrical circuitry) arranged within the ECU 100. Hereinafter, a step will be abbreviated as S. The same applies to FIG. 7, which will be described later.

[0052] In S101, the ECU 100 determines the status of plug-in charging of the vehicle 1. In the example shown in Fig. 4, it is determined whether plug-in charging has been resumed, whether plug-in charging has been continued after being resumed, or whether plug-in charging has been terminated.

[0053] When plug-in charging is resumed ("Resume" in S101), ECU 100 determines whether the interruption time ΔT of plug-in charging is less than a predetermined time (S102). The predetermined time is the time required for the reaction unevenness during the interruption of plug-in charging to be sufficiently alleviated (resolved), and is usually about several minutes to 10 minutes.

[0054] If the interruption time ΔT of the plug-in charging is less than the predetermined time (YES in S102), the ECU 100 sets the target temperature of the battery 21 to TAG2 (S103), and then the ECU 100 controls the electric heater 22 to resume heating of the battery 21 (S104).

[0055] Returning to S101, if plug-in charging is continued after being restarted ("Continue after restart" in S101), ECU 100 executes the process (S105 to S108) for determining whether the uneven reaction due to heating has been resolved based on battery voltage VB. Note that the order of the processes of S105 to S108 can be changed as appropriate.

[0056] In S105, the ECU 100 acquires the detected value of the battery voltage VB from the voltage sensor .

[0057] In S106, the ECU 100 estimates the SOC of the battery 21. As a method for estimating the SOC, a known method such as a method using a charge / discharge curve (OCV-SOC curve) or a current integration method can be used.

[0058] In S107, the ECU 100 acquires the detected value of the battery temperature TB from the temperature sensor 25. Although not shown, when detected values ​​of the temperatures of multiple cells are acquired from multiple temperature sensors, it is preferable to adopt the lowest temperature among the temperatures of the multiple cells as the detected value of the battery temperature TB. This is because it is believed that if the reaction unevenness of the lowest temperature cell is eliminated, the reaction unevenness of all cells will also be eliminated.

[0059] In S108, the ECU 100 sets the reference voltage Vref based on the SOC and battery temperature TB of the battery 21. For example, the memory 102 of the ECU 100 stores a map that defines the correspondence between the SOC, battery temperature TB, and reference voltage Vref. The ECU 100 can set the reference voltage Vref from the SOC and battery temperature TB by referring to the map. This map will be described later with reference to FIG. 5.

[0060] In S109, the ECU 100 determines whether the battery voltage VB is equal to or lower than the reference voltage Vref. If the battery voltage VB is higher than the reference voltage Vref (NO in S109), in other words, if the battery voltage VB has not dropped to the reference voltage Vref, the reaction unevenness has not yet been resolved. Therefore, the ECU 100 maintains the target temperature of the battery 21 at TAG2 to continue heating at a high temperature (S103). On the other hand, if the battery voltage VB is equal to or lower than the reference voltage Vref, in other words, if the reaction unevenness is resolved and the battery voltage VB falls below the reference voltage Vref, the ECU 100 returns the target temperature of the battery 21 from TAG2 to TAG1 (S110). Then, the ECU 100 controls the electric heater 22 to continue heating the battery 21 (S104).

[0061] Returning to S101 again, if the plug-in charging has been completed ("Completed" in S101), the ECU 100 controls the electric heater 22 to terminate heating of the battery 21 (S111).

[0062] As described above, in the first embodiment, if a short pause shorter than a predetermined time (for example, about several minutes to 10 minutes) is inserted during plug-in charging of battery 21, which is an all-solid-state battery, the target temperature of the temperature-raising process of battery 21 is raised after plug-in charging is resumed. As a result, after plug-in charging is resumed, battery temperature TB rises compared to before the short pause. This promotes mitigation of reaction irregularities and reduces overvoltage caused by reaction irregularities. Therefore, even if battery voltage VB rises when plug-in charging is resumed, the rise in battery voltage VB can be made gentler by the amount that the overvoltage that increased during the short pause is reduced. Therefore, according to the first embodiment, it is possible to prevent inconvenience caused by reaction irregularities.

[0063] FIG. 5 is a conceptual diagram showing an example of a map used to set the reference voltage Vref. As shown in FIG. 5, the higher the SOC of the battery 21, the higher the reference voltage Vref is set. The higher the SOC of the battery 21, the higher the OCV of the battery 21 and therefore the higher the battery voltage VB. Therefore, it is preferable to set the reference voltage Vref higher as the battery voltage VB increases. This is because if the reference voltage Vref remains low, the battery voltage VB may not decrease to the reference voltage Vref or it may take an excessively long time for the battery voltage VB to decrease to the reference voltage Vref. By setting the reference voltage Vref higher as the SOC of the battery 21 increases, it is possible to ensure that the battery voltage VB decreases to the reference voltage Vref and to ensure an appropriate heating time.

[0064] Furthermore, the lower the voltage temperature TB, the lower the reference voltage Vref is set. The lower the voltage temperature TB, the more difficult it is to alleviate reaction unevenness and reduce overvoltage. Therefore, it is preferable to set the reference voltage Vref lower as the voltage temperature TB decreases, thereby lengthening the time it takes for the battery voltage VB to fall below the reference voltage Vref. This allows a longer heating time to be secured to eliminate reaction unevenness and reduce overvoltage.

[0065] 5 shows an example of a three-dimensional map that defines the correspondence relationship between the SOC, the battery temperature TB, and the reference voltage Vref. However, instead of this, a two-dimensional map that defines the correspondence relationship between the SOC and the reference voltage Vref, or a two-dimensional map that defines the correspondence relationship between the battery temperature TB and the reference voltage Vref, may be used. Alternatively, the reference voltage Vref may be a fixed value.

[0066] Also, in S103 and S110, the target temperature of the temperature increase process is controlled. However, the parameter to be controlled is not limited to the target temperature, and may be the amount of heat (unit: W or Wh) of the battery 21 by the electric heater 22. The parameter to be controlled may be the amount of temperature increase (unit: °C) from a predetermined temperature, or the amount of temperature increase per unit time (unit: °C / sec). The battery temperature TB can also be suitably controlled by controlling the amount of heat, the amount of temperature increase, and / or the amount of temperature increase per unit time of the battery 21.

[0067] [Embodiment 2] In the first embodiment, it has been explained that whether or not the response unevenness has been resolved is determined based on the reference voltage Vref. In the second embodiment, a configuration will be described in which time is used instead of voltage. The overall configuration of the vehicle according to the second embodiment is the same as the configuration shown in FIG.

[0068] 6 is a time chart for illustrating a method for adjusting a target temperature in a temperature increase process according to the second embodiment. This time chart differs from the time chart according to the first embodiment (see FIG. 3) in that a time condition is used instead of a voltage condition at time t23. The time condition is whether the elapsed time from the time (time t21) when plug-in charging was interrupted has exceeded a reference time tref. Other details are the same as those in the first embodiment (see FIG. 3), and therefore detailed description will not be repeated.

[0069] 7 is a flowchart showing the procedure of the temperature increase process according to embodiment 2. The processes of S201 to S204 are the same as the processes of S101 to S104 in embodiment 1 (see FIG. 4).

[0070] If plug-in charging is continued after being restarted ("Continue after restart" in S201), ECU 100 executes processing (S205 to S207) for determining, based on time, whether the uneven reaction has been resolved by heating.

[0071] In S205, the ECU 100 acquires the detected value of the battery temperature TB from the temperature sensor 25.

[0072] In S206, the ECU 100 sets the reference time tref based on the battery temperature TB. For example, a map that defines the correspondence between the battery temperature TB and the reference time tref is stored in the memory 102 of the ECU 100. The ECU 100 can set the reference time tref from the battery temperature TB by referring to the map.

[0073] It is preferable that the reference time tref is set longer as the battery temperature TB is lower. As described in the first embodiment, the lower the battery temperature TB is, the more difficult it is to alleviate the reaction unevenness, so that a longer heating time is ensured to alleviate the reaction unevenness and reduce the overvoltage.

[0074] However, the method for setting the reference time tref is not limited to this. The reference time tref may be any time as long as it is shorter than the time required for the reaction unevenness to disappear while plug-in charging is interrupted (the above-mentioned predetermined time). The reference time tref may be the remaining time obtained by subtracting the interruption time ΔT of plug-in charging from the predetermined time. For example, if the predetermined time is 10 minutes and the interruption time ΔT is 3 minutes, the reference time tref can be set to 7 minutes. The reference time tref may also be a fixed value.

[0075] In S207, ECU 100 determines whether the elapsed time since the plug-in charging was interrupted is equal to or longer than reference time tref. If the elapsed time is shorter than reference time tref (NO in S207), it is considered that the reaction unevenness has not yet been resolved. Therefore, ECU 100 maintains the target temperature of battery 21 at TAG2 to continue heating at a high temperature (S203). Then, ECU 100 controls electric heater 22 to continue heating battery 21 (S204). On the other hand, if the elapsed time is equal to or longer than reference time tref (YES in S207), it is highly likely that the reaction unevenness has been resolved, so ECU 100 returns the target temperature of battery 21 from TAG2 to TAG1 (S208). Then, ECU 100 controls electric heater 22 to continue heating battery 21 (S204). The subsequent process of S209 is equivalent to the process of S111 in the first embodiment.

[0076] As described above, in the second embodiment, similar to the first embodiment, if a short pause of less than a predetermined time is inserted in the plug-in charging of the battery 21, the target temperature of the temperature increase process of the battery 21 is raised after the plug-in charging is resumed. This makes it possible to prevent inconveniences caused by uneven reaction.

[0077] In the first and second embodiments, the configuration in which the electric heater 22 is employed as the "heating device" according to the present disclosure has been described. However, the "heating device" according to the present disclosure is not limited to this as long as it is configured to heat the battery 21, which is an all-solid-state battery.

[0078] Although not shown, a vehicle configuration may be considered that includes a liquid-cooled temperature regulation system in which a common coolant flows through the powertrain system (PCU 31 and motor generator 32) and the battery 21. In such a vehicle configuration, the "heating device" according to the present disclosure may be the powertrain system. The battery 21 can be heated by using heat generated by the powertrain system to heat the coolant and then circulating the heated coolant through the battery 21. In this case, the motor generator 32 may be intentionally driven in a state where heat loss is large. More specifically, field strengthening control / field weakening control of the motor generator 32 may be performed so that the operating point of the motor generator 32, expressed on the current advance angle-torque plane, deviates from the optimal operating line where heat loss is minimized.

[0079] Alternatively, a configuration is also possible in which heat is exchanged between a heat pump type air conditioner and a liquid-cooled cooling device for the battery 21 via a heat exchanger. In such a vehicle configuration, the "heating device" according to the present disclosure may be the air conditioner. As in the example of the powertrain system described above, the battery 21 can be heated by using heat generated by the air conditioner to heat the coolant and circulating the heated coolant through the battery 21.

[0080] 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]

[0081] 1 Vehicle, 10 Charging unit, 11 Inlet, 12 Converter, 13 Charging relay, 20 Battery pack, 21 Battery, 22 Electric heater, 23 Voltage sensor, 24 Current sensor, 25 Temperature sensor, 30 Drive unit, 31 PCU, 32 Motor generator, 40 Drive wheels, 100 ECU, 101 Processor, 102 Memory, 103 Storage.

Claims

1. All-solid-state batteries and a heating device that heats the all-solid-state battery; a control device for controlling the heating device, when charging of the all-solid-state battery is resumed after an interruption of less than a predetermined time, the control device controls the heating device to increase the temperature of the all-solid-state battery after the charging is resumed above the temperature of the all-solid-state battery before the charging was interrupted.

2. The all-solid-state battery includes an active material, The all-solid-state battery system according to claim 1 , wherein the predetermined time is a time required for uneven reaction occurring in the active material to be resolved during the interruption of the charging.

3. Further comprising a voltage sensor for detecting a voltage of the all-solid-state battery; 3. The all-solid-state battery system according to claim 1, wherein, when the detected value of the voltage sensor after the resumption of charging falls below a reference voltage, the control device controls the heating device to reduce the temperature of the all-solid-state battery after the detected value of the voltage sensor has exceeded the reference voltage below a temperature of the all-solid-state battery before the detected value of the voltage sensor fell below the reference voltage.

4. Further comprising a temperature sensor for detecting a temperature of the all-solid-state battery; The all-solid-state battery system according to claim 3 , wherein the control device sets the reference voltage lower as the detected value of the temperature sensor becomes lower.

5. The all-solid-state battery system according to claim 3 , wherein the control device sets the reference voltage higher as the SOC of the all-solid-state battery increases.

6. 3. The all-solid-state battery system according to claim 1, wherein, when an elapsed time since the interruption of the charging exceeds a reference time after the resumption of the charging, the control device controls the heating device to lower a temperature of the all-solid-state battery after the elapsed time has exceeded the reference time below a temperature of the all-solid-state battery before the elapsed time exceeded the reference time.

7. The all-solid-state battery system according to claim 6 , wherein the reference time is shorter than the predetermined time.

8. The all-solid-state battery system according to claim 7 , wherein the reference time is a remaining time obtained by subtracting a time during which the charging was interrupted from the predetermined time.

9. Further comprising a temperature sensor for detecting a temperature of the all-solid-state battery; The all-solid-state battery system according to claim 6 , wherein the control device sets the reference time to be longer as the detected value of the temperature sensor becomes lower.

10. A vehicle comprising the all-solid-state battery system according to claim 1.

11. Charging the solid-state battery; and when the charging is resumed after an interruption of less than a predetermined time, heating the all-solid-state battery so that a temperature of the all-solid-state battery after the charging is resumed is higher than a temperature of the all-solid-state battery before the charging was interrupted.

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