Battery control system and battery control method

Abstract

To achieve both suppression of deterioration of a battery and securement of a charge amount suitable for starting or the like.SOLUTION: The battery control system 1 includes the battery control unit 11 that controls charging of the first battery 2 and the second battery 3, and the charge amount monitoring unit 31 that functions as a battery monitoring unit that monitors the charge amounts of the first battery 2 and the second battery 3. The battery control unit 11 charges the second battery 3 based on the monitoring result of the charging amount monitoring unit 31 such that the charging amount of the second battery 3 does not exceed a first threshold k1 for suppressing battery degradation when the predetermined operation is being performed, and performs primary supplementary charging for charging the second battery 3 to a second threshold k1 higher than the first threshold k2 when the predetermined operation is completed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery control system and a battery control method. [Background technology]

[0002] In recent years, research and development into battery charging has been conducted to contribute to energy efficiency so that more people can have access to affordable, reliable, sustainable, and advanced energy. Patent Document 1 discloses a supplementary charging system that uses a DC / DC converter to charge a low-voltage battery with power from a high-voltage battery when the remaining capacity of the low-voltage battery is below a threshold. This system controls the charging state during supplementary charging to prevent deterioration of the low-voltage battery by not bringing it to a full charge state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-304393 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in this technology related to battery charging, a challenge is to simultaneously suppress deterioration and ensure an appropriate amount of charge for a second battery, such as a low-voltage battery, that is charged with power from a first battery, such as a high-voltage battery. For example, if the second battery is a lithium-ion battery, it is prone to degradation if it is kept at a high voltage (high SOC (States of Charge)) and a high temperature. Therefore, if a high voltage is continuously applied, even during charging, the SOC increases, accelerating degradation. Maintaining a low voltage while the DC / DC converter is running, such as during driving or external charging, in order to suppress degradation often results in a low SOC. Therefore, it becomes difficult to ensure power and startup when the vehicle is stopped after the DC / DC converter has finished starting up, and there is room for improvement in achieving both suppression of degradation and ensuring an appropriate charge amount. The present invention aims to solve the above-mentioned problems by suppressing battery degradation while ensuring an appropriate charge level for startup, etc. This will ultimately contribute to improving energy efficiency. [Means for solving the problem]

[0005] One aspect of the present disclosure is a battery control system mounted on a mobile body, comprising: a first battery that stores power for driving a power unit; a power conversion unit that converts the power stored in the first battery into a predetermined power; a second battery that is charged with the predetermined power; a battery control unit that controls the charging of the first battery and the second battery; and a battery monitoring unit that monitors the charge amounts of the first battery and the second battery; wherein, when the mobile body is performing a predetermined operation, the battery control unit charges the second battery based on the monitoring results of the battery monitoring unit so that the charge amount of the second battery does not exceed a first threshold that suppresses battery deterioration; and when the mobile body has completed the predetermined operation, the battery control system performs primary auxiliary charging to charge the second battery to a second threshold that is higher than the first threshold.

[0006] Another aspect of the present disclosure is a battery control method for a mobile body including a first battery that stores power for driving a power unit, a power conversion unit that converts the power stored in the first battery to a predetermined power, a second battery that is charged with the predetermined power, a battery control unit that controls the charging of the first battery and the second battery, and a battery monitoring unit that monitors the charge amounts of the first battery and the second battery, wherein, when the mobile body is performing a predetermined operation, the battery control unit charges the second battery based on the monitoring results of the battery monitoring unit so that the charge amount of the second battery does not exceed a first threshold that suppresses battery deterioration, and when the mobile body has completed the predetermined operation, the battery control method performs a primary auxiliary charge to charge the second battery to a second threshold that is higher than the first threshold. [Effects of the Invention]

[0007] According to one embodiment of the present invention, it is possible to suppress deterioration of a battery and ensure an appropriate charge amount for startup or the like. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a battery control system according to this embodiment. [Figure 2] FIG. 2 is a flowchart showing a battery control method. [Figure 3] FIG. 3 is a diagram showing an example of a change over time in the charge amount of the second battery. [Figure 4] FIG. 4 is a diagram showing an example of the determination process in step S3. [Figure 5] FIG. 5 is a diagram showing another example of the change over time in the charge amount of the second battery. [Figure 6] FIG. 6 is a diagram for explaining emergency supplementary charging. [Figure 7] FIG. 7 is a diagram illustrating the first modified example. [Figure 8] FIG. 8 is a diagram for explaining the second and third modified examples. DETAILED DESCRIPTION OF THE INVENTION

[0009] [1. Configuration of Battery Control System 1] FIG. 1 is a diagram showing a battery control system 1 according to this embodiment. The battery control system 1 is equipped with a host control unit 10 consisting of a central ECU that performs overall control of the vehicle and performs information processing. The host control unit 10 is connected to multiple ECUs that control the operation of the vehicle via communication lines, and functions as a gateway that manages the exchange of communication data.

[0010] 1 shows a lower-level control unit 20 consisting of a first battery ECU that monitors a first battery 2 of a mobile object, and a lower-level control unit 30 consisting of a second battery ECU that monitors a second battery 3 of the mobile object, among a plurality of ECUs that are communicatively connected to a higher-level control unit 10. The higher-level control unit 10 and the lower-level control units 20 and 30 operate in cooperation with each other to charge the first battery 2 and the second battery 3.

[0011] The mobile body on which the battery control system 1 is mounted is a vehicle classified as an electric vehicle (EV), and includes a traction motor that functions as a power unit, a first battery 2 that is a relatively large-capacity high-voltage battery that stores power to drive the traction motor, and a second battery 3 that is a relatively small-capacity low-voltage battery that stores power to drive the vehicle's accessories. The vehicle may be a hybrid electric vehicle (e.g., HEV). The mobile body of the present disclosure is not limited to a vehicle, and may also be an aircraft, a ship, or the like.

[0012] The first battery 2 and the second battery 3 are secondary batteries, and in this embodiment, are lithium-ion batteries. The first battery 2 is charged with power from a charging facility. The traction motor also functions as a regenerative brake, and the generated power is recovered by the first battery 2. The power stored in the first battery 2 is converted into power for driving the motor and supplied to the traction motor, and is also used to charge the second battery 3. The first battery 2 can be referred to as a main battery or a traction battery. The second battery 3 can be referred to as a sub-battery or an auxiliary battery.

[0013] The vehicle also includes a power conversion unit 4 that converts the power stored in the first battery 2, and an external communication unit 5 that communicates with a server outside the vehicle. The power conversion unit 4 includes a DC-DC converter that converts the power stored in the first battery 2 into charging power for the second battery 3. The external communication unit 5 is also used for telematics, software updates, etc.

[0014] The upper control unit 10 has a microcomputer configuration including a processor and memory, and functions as a battery control unit 11, a battery information acquisition unit 12, a vehicle information acquisition unit 13, a threshold setting unit 14, a timer processing unit 15, a charging feasibility determination unit 16, an abnormality determination unit 17, and a communication status detection unit 18 by the processor reading and executing a program stored in the memory.

[0015] The battery control unit 11 performs processing to control the charging of the first battery 2 and the second battery 3 by utilizing the monitoring results of the lower-level control units 20 and 30. The battery control unit 11 may directly control the charging of the first battery 2 and the second battery 3, or may control the charging of the first battery 2 and the second battery 3 via another ECU such as a lower-level control unit.

[0016] The battery information acquisition unit 12 performs processing to acquire battery information regarding the first battery 2 and the second battery 3. The battery information includes the results of monitoring the first battery 2 and the second battery 3 by the lower-level control units 20 and 30 (including the charge amount), and information (such as voltage, current, and temperature) detected by battery management units (hereinafter referred to as BMUs) provided in the batteries 2 and 3.

[0017] In this embodiment, the information indicating the charge amount of the batteries 2 and 3 is the SOC (State Of Charge), which is estimated from the voltage of the batteries 2 and 3 or calculated by integrating the current. By using the SOC, the charge amount of the batteries 2 and 3 can be determined with high accuracy. However, the information indicating the charge amount does not have to be limited to the SOC. The battery information acquisition unit 12 can also be referred to as a battery voltage acquisition unit, a battery current acquisition unit, a battery temperature acquisition unit, and a battery charge amount acquisition unit.

[0018] The vehicle information acquisition unit 13 performs a process of acquiring vehicle information, which is information related to the vehicle. The vehicle information is information detected by sensors or the like provided in the vehicle, and includes information indicating the operating state of the vehicle, information indicating the open / closed state of opening / closing members provided in the vehicle, and information related to battery charging (such as outside air temperature). The information indicating the operating state of the vehicle is information that can identify whether the vehicle is running, whether the vehicle is not running (parked), whether the first battery 2 is charging, whether the second battery 3 is charging, and whether the power conversion unit 4 is operating while the vehicle is parked, and includes information such as whether the vehicle is powered on (e.g., ignition on), whether the vehicle is powered off (e.g., ignition off), and vehicle speed.

[0019] The opening and closing members of the vehicle include the hood (also called a bonnet), doors, and luggage compartment of the vehicle. The open / closed states of these opening and closing members are detected by sensors provided in the vehicle and transmitted to the vehicle information acquisition unit 13. Note that vehicle information is an example of mobile object information.

[0020] The threshold setting unit 14 performs processing to set thresholds related to charging of the second battery 3 based on the temperature of the second battery 3. For example, the threshold setting unit 14 can set each threshold based on table data describing the correspondence between the temperature of the second battery 3 and each threshold (a first threshold k1, a second threshold k2, and a third threshold k3, which will be described later), or on data of a relational expression indicating the correspondence between the temperature of the second battery 3 and each threshold. The temperature of the second battery 3 is not limited to a temperature detected by a sensor such as a BMU, and may be a temperature estimated from the outside air temperature or weather information. The threshold setting unit 14 may set the threshold based on a combination of the temperature of the second battery 3 and the charge amount (remaining capacity) of the first battery 2, or may set the threshold based on a combination of the charge amount (remaining capacity) of the first battery 2 and the charge amount (remaining capacity) of the second battery 3.

[0021] The timer processing unit 15 performs processes related to the timer, such as setting, starting, and stopping the timer. The charging feasibility determination unit 16 performs processes such as determining whether the second battery 3 can be charged based on vehicle information, transmitting the determination result to a lower-level control unit, and transmitting the threshold set by the threshold setting unit 14 to the lower-level control unit.

[0022] The abnormality determination unit 17 performs a process of determining whether at least the second battery 3 out of the first battery 2 and the second battery 3 is in an abnormal state. The communication state detection unit 18 performs processing to detect the communication state between the upper control unit 10 and the lower control unit.

[0023] The upper control unit 10 uses the chargeability determination unit 16 to determine whether or not the second battery 3 can be charged, based on the determination result of the abnormality determination unit 17 and the detection result of the communication state detection unit 18, and performs control related to the charging of the second battery 3 according to the determination result. Note that a detailed description of the control related to the charging of the first battery 2 in the battery control system 1 will be omitted.

[0024] In the following description, when the plurality of lower control units 20, 30 are to be particularly distinguished from one another, the lower control unit 20 will be referred to as a first lower control unit 20, and the lower control unit 30 will be referred to as a second lower control unit 30. The first lower control unit 20 has a microcomputer configuration including a processor and a memory, and functions as a charge amount monitoring unit 21 and a charge necessity determining unit 22 by the processor reading and executing a program stored in the memory.

[0025] The charge amount monitoring unit 21 monitors the charge amount, which is composed of an SOC estimated from the voltage of the first battery 2 detected by the BMU or calculated by integrating the current. The charge amount monitoring unit 21 constantly monitors the charge amount of the first battery 2 while the first lower control unit 20 is awake, and intermittently monitors the charge amount of the first battery 2 while the first lower control unit 20 is asleep. The charge amount of the first battery 2 may be calculated by the charge amount monitoring unit 21 or the BMU. The charging necessity determining unit 22 determines whether charging of the first battery 2 is necessary based on the monitoring result of the charge amount monitoring unit 21 and the like, and transmits information based on the determination result to the upper control unit 10.

[0026] The second lower control unit 30 has a microcomputer configuration including a processor and a memory, and functions as a charging amount monitoring unit 31 and a charging necessity determining unit 32 by the processor reading and executing a program stored in the memory. The charge amount monitoring unit 31 monitors the charge amount, which is composed of an SOC estimated from the voltage of the second battery 3 detected by the BMU or calculated by integrating the current. The charge amount monitoring unit 31 constantly monitors the charge amount of the second battery 3 while the second lower control unit 30 is awake, and intermittently monitors the charge amount of the second battery 3 while the second lower control unit 30 is asleep. The charge amount of the second battery 3 may be calculated by the charge amount monitoring unit 31 or the BMU. The charging necessity determining unit 32 determines whether charging of the second battery 3 is necessary based on the monitoring result of the charge amount monitoring unit 31, and transmits information based on the determination result (for example, a charging request) to the upper control unit .

[0027] [2. Operation of Battery Control System 1] The battery control method will be described with reference to the flowchart shown in Fig. 2. The battery control method in this description is a control method relating to charging of the second battery 3, and can be called a battery charging method. As shown in FIG. 2, the battery control unit 11 of the upper control unit 10 determines whether the vehicle is in a predetermined operation based on the vehicle information acquired by the vehicle information acquisition unit 13 (step S1).

[0028] The predetermined operation is an operating state in which charging is possible immediately even if the charge level of the second battery 3 decreases, and in this embodiment includes a state in which the vehicle is running, a state in which the first battery 2 is being charged, and a state in which the power conversion unit 4 is operating while the vehicle is stopped. Therefore, when the vehicle is running, a state in which the first battery 2 is being charged, or a state in which the power conversion unit 4 is operating while the vehicle is stopped, the battery control unit 11 determines that the vehicle is in a predetermined operation (step S1 / YES).

[0029] When the vehicle is in a predetermined operation (step S1 / YES), the battery control unit 11 sets a first threshold k1 using the threshold setting unit 14, and controls the charging of the second battery 3 based on the monitoring results of the second lower control unit 30 so that the charge amount of the second battery 3 does not exceed the first threshold k1 (step S2).

[0030] The first threshold k1 is set to a value that defines the charge amount that suppresses battery degradation. It is generally known that lithium ion batteries are prone to deterioration when exposed to high voltage (high SOC (States Of Charge)) and high temperature conditions for a long period of time. In this embodiment, the first threshold k1 is set to a value below the high SOC and equal to or greater than the charge amount that can ensure vehicle startup, thereby suppressing battery deterioration. For example, when the temperature of the second battery 3 is 0°C or higher, the first threshold k1 is set to a value of 40% or less of charge; when the temperature of the second battery 3 is 0°C or lower or higher than -25°C, the first threshold k1 is set to a value of 50% or less of charge; and when the temperature of the second battery 3 is -25°C or lower, the first threshold k1 is set to a value of 60% or less of charge.

[0031] Fig. 3 is a diagram showing an example of temporal changes in the charge amount of the second battery 3, with the vertical axis in Fig. 3 representing the charge amount of the second battery 3 and the horizontal axis representing time. Fig. 3 shows a case in which the vehicle changes from being in motion to being powered off (ignition off), to being externally charged (corresponding to charging of the first battery 2), and then back to being powered off again. As shown in FIG. 3, during the vehicle's predetermined operations of "driving" and "external charging," charging of the second battery 3 is carried out in step S2, and the second battery 3 is maintained at a charge amount equivalent to the first threshold k1 ("SOC maintenance" in FIG. 3).

[0032] During a predetermined operation of the vehicle, the second battery 3 does not exceed the first threshold k1, and therefore the second battery 3 does not reach a high voltage (corresponding to a high SOC). This makes it possible to suppress accelerated deterioration of the second battery 3. Furthermore, since the second battery 3 has a charge amount sufficient to ensure the vehicle can be started, it is possible to avoid situations in which insufficient charge in the second battery 3 affects the start-up of the vehicle. Returning to FIG. 2, when it is determined that the predetermined operation is not in progress (step S1 / NO), the battery control unit 11 causes the chargeability determination unit 16 to determine whether the second battery 3 can be charged (step S3).

[0033] FIG. 4 is a diagram showing an example of the determination process in step S3. 4, the chargeability determination unit 16 determines whether the charge amount of the first battery 2 is equal to or less than a predetermined threshold kmin based on the monitoring results of the first lower-level control unit 20 (step S1a). The threshold kmin is a value equivalent to the lower limit of the charge amount of the first battery 2 within a range that does not excessively impede vehicle travel. In other words, the threshold kmin is set to a value equivalent to the minimum charge amount of the first battery 2 at which charging of the second battery 3 using the power of the first battery 2 is permitted.

[0034] If the charge amount of the first battery 2 is equal to or less than the threshold kmin (step S1a / YES), the chargeability determination unit 16 determines that the second battery 3 cannot be charged (step S2a). Since it is determined that the second battery 3 cannot be charged, it is possible to avoid a situation in which the charge amount of the first battery 2 drops excessively by charging the second battery 3. When the charge level of the first battery 2 is equal to or lower than the threshold kmin, the battery control unit 11 does not charge the second battery 3, and therefore does not perform primary auxiliary charging or secondary auxiliary charging, which will be described later. This prevents the charge level of the first battery 2 from excessively decreasing due to auxiliary charging.

[0035] If the charge amount of the first battery 2 exceeds the threshold kmin (step S1a / NO), the charge possibility determination unit 16 determines, based on the vehicle information, whether or not any of the hood, doors, or luggage compartment of the vehicle has been opened within a predetermined period after the vehicle power has been turned off (step S3a).If none of the hood, doors, or luggage compartment has been opened (step S3a / NO), the charge possibility determination unit 16 determines that the second battery 3 is chargeable (step S4a).

[0036] On the other hand, if any of the hood, doors, and luggage compartment is open (step S3a / YES), the charging feasibility determination unit 16 waits for a predetermined waiting time (step S5a) and then determines that the second battery 3 is chargeable (step S4a). The predetermined period of step S3a and the waiting time of step S5a are set to a time sufficient for a user (e.g., the driver) or worker to open the hood, door, or luggage compartment after the predetermined vehicle operation has been completed (e.g., after the ignition is turned off) to access the interior of the vehicle and perform predetermined tasks such as inspecting, checking, replacing parts, and repairing the vehicle.

[0037] The charging feasibility determination unit 16 also determines that charging of the second battery 3 is not possible in the following cases 1 to 4: 1) When the vehicle has been left unused for a predetermined period of time (for example, the duration of time the power has been off) is equal to or longer than a predetermined period of time (for example, 90 days). 2) When a malfunction of the high-voltage system (including the first battery 2) is detected. 3) When a malfunction of the second battery 3 is detected. 4) When a malfunction of the timer function of the upper control unit 10 is detected.

[0038] The upper level control unit 10 does not determine that the second battery 3 can be charged from the predetermined period through the standby time, thereby preventing a situation in which charging of the second battery 3 interferes with predetermined operations. This prevents a situation in which the replacement of the second battery 3 and measurement of the second battery 3 by a tester are hindered.

[0039] Returning to FIG. 2, if the chargeability determination unit 16 determines that the second battery 3 cannot be charged (step S3 / chargeability not possible), the process proceeds to step S1. On the other hand, if the chargeability determining unit 16 determines that the second battery 3 is chargeable, the second lower control unit 30 causes the charge necessity determining unit 32 to determine whether or not the second battery 3 needs to be charged (step S3).

[0040] The charging necessity determination unit 32 determines whether or not the condition that the second battery 3 can be charged and the charge amount of the second battery 3 is equal to or less than the first threshold k1 is satisfied, based on the charge amount of the second battery 3, etc. If the condition is satisfied, it determines that the second battery 3 needs to be charged (step S4 / charging required), and if the condition is not satisfied, it determines that the second battery 3 does not need to be charged (step S4 / charging not required).

[0041] When the charging necessity determining unit 32 determines that the second battery 3 needs to be charged, it transmits a charging request to the upper control unit 10. If for some reason the upper control unit 10 does not accept a request for charging or other such communication, the charging necessity determination unit 32 retries to transmit the request for charging or other such communication at predetermined intervals. If the result of the retry is that the upper control unit 10 does not accept the communication and the charge amount of the second battery 3 falls below a predetermined threshold, it is preferable to perform processing to notify the user of the vehicle of this fact.

[0042] If it is determined that the second battery 3 does not need to be charged, the battery control unit 11 proceeds to the process of step S1. On the other hand, if it is determined that the second battery 3 needs to be charged, that is, if a charge request is transmitted to the upper control unit 10, the battery control unit 11 proceeds to the process of step S5.

[0043] In step S5, the battery control unit 11 sets a second threshold k2 higher than the first threshold k1 using the threshold setting unit 14, and controls the charging of the second battery 3 so that the charge amount of the second battery 3 does not exceed the second threshold k2 based on the monitoring result of the second lower control unit 30. As a result, as shown in Fig. 3, when the predetermined operation is completed and the power is turned off (ignition is turned off), the second battery 3 is charged up to the second threshold k2. The charging in step S5 corresponds to "primary supplemental charging of the second battery 3."

[0044] By performing primary auxiliary charging of the second battery 3, even if the charge level of the second battery 3 decreases due to dark current and the operation of auxiliary devices when the power is turned off after a specified operation has finished, it is possible to prevent the charge level of the second battery 3 from decreasing excessively. Because the second battery 3 is used to start the vehicle, it is possible to prevent problems with starting the vehicle.

[0045] 3 and the figures described below, "discharge" indicates a case where the charge amount of the second battery 3 is reduced due to dark current, etc. The second threshold k2 is set to a value higher than the first threshold k1, which prevents battery degradation while avoiding supplemental charging after the first supplemental charging as much as possible. 2, after performing primary auxiliary charging of the second battery 3 (step S5), the battery control unit 11 sets a third threshold k3 (FIG. 5) that is lower than the first threshold k1 using the threshold setting unit 14. Then, the battery control unit 11 calculates a first timer time t1, which corresponds to an estimated time until the amount of charge of the second battery 3 decreases from the current value to the third threshold k3 or less, using the timer processing unit 15, and starts measuring the first timer time t1 (step S6).

[0046] The third threshold k3 is set to a value lower than the first threshold k1 and within a range of the charge amount of the second battery 3 that can ensure the start of the vehicle. The first timer time t1 is set to a time that takes into consideration at least discharge due to dark current or the like while the vehicle is left standing. In addition, the first timer time t1 may be set based on information obtained from a server, such as power information required for communication scheduled while the vehicle is stopped, or the first timer time t1 may be set based on a combination of information obtained from a server and the charge amount (remaining capacity) of the second battery 3.

[0047] The second lower-level control unit 30 determines whether the charge amount of the second battery 3 has become equal to or less than the third threshold k3 based on the monitoring result of the charge amount monitoring unit 31 (step S7). In addition, the battery control unit 11 determines whether the first timer time t1 has elapsed (step S8). When the charge amount of the second battery 3 becomes equal to or less than the third threshold k3 (step S7 / YES), or when the first timer time t1 has elapsed (step S8 / YES), the battery control unit 11 controls the charging of the second battery 3 (step S9). The charging in step S9 corresponds to "secondary supplementary charging of the second battery 3."

[0048] Fig. 5 is a diagram showing another example of the change over time in the charge amount of the second battery 3. Fig. 5 shows a case where the power-off state continues for a longer period of time than the case shown in Fig. 3. The example shown in Fig. 5 illustrates a case where the charge amount of the second battery 3 reaches the third threshold value k3 at the timing when the first timer time t1 estimated by the timer processing unit 15 has elapsed. 5, secondary auxiliary charging of the second battery 3 is performed when the first timer time t1 has elapsed, so even if the second battery 3 is discharged due to dark current or the like, the state of charge of the second battery 3 does not fall below the third threshold k3. Therefore, the second battery 3 can be auxiliary charged while suppressing battery degradation due to excessive charging.

[0049] 2, in step S9, the battery control unit 11 starts charging the second battery 3 so that the charge amount of the second battery 3 does not exceed the first threshold k1 based on the monitoring result of the second lower control unit 30. The first threshold k1 is a value within a range of charge amounts that does not accelerate deterioration of the second battery 3 and is a value within a range of charge amounts of the second battery 3 that can ensure starting of the vehicle, so it is possible to prevent a situation in which starting of the vehicle is affected while suppressing deterioration of the second battery 3.

[0050] However, due to factors such as the vehicle usage environment, the deterioration state of the second battery 3, and individual differences in the second battery 3, there is a risk that the charge amount of the second battery 3 will decrease to the third threshold k3 earlier than the timing at which the first timer time t1 has elapsed. FIG. 6 shows an example of the change over time in the charge amount of the second battery 3 in this case. As shown in Figures 2 and 6, when the vehicle is not in a predetermined operation, if the charge amount of the second battery 3 becomes equal to or less than the third threshold k3 (step S7 / YES), secondary auxiliary charging of the second battery 3, which consists of processing in step S9, is forcibly started even if the first timer time t1 has not elapsed.

[0051] Forcibly charging the second battery 3 before the first timer time t1 has elapsed corresponds to "emergency supplementary charging" (see FIG. 6). When emergency supplemental charging begins, the battery control unit 11 uses the abnormality determination unit 17 to determine whether or not there is a charging abnormality in the second battery 3, and if there is a charging abnormality, performs processing to notify the vehicle user of the charging abnormality. A wide range of known processing can be applied to the processing for determining a charging abnormality. For example, a method of determining a charging abnormality may be used, such as a method of determining a charging abnormality when the voltage or charge amount of the second battery 3 does not increase normally even after charging, or a method of counting the number of emergency supplemental charges and determining a charging abnormality when this number exceeds a predetermined percentage of the total number of charges or the number of charges within a certain period.

[0052] Furthermore, a wide range of known processes can be applied to the process of notifying the vehicle user of charging abnormalities, etc. For example, a process of transmitting notification information to a display device provided in the vehicle or a user terminal carried by the user can be applied.

[0053] When emergency supplemental charging is performed, the second battery 3 may not have appropriate performance. For example, this may occur if the second battery 3 has deteriorated to the point where it is no longer able to maintain sufficient voltage or capacity, or if the second battery 3 has been replaced with a battery with lower performance. In such a case, the second battery 3 is determined to have a charging abnormality, and the user can be promptly notified of the charging abnormality. In this embodiment, the system determines whether the second battery 3 has a charging abnormality when a predetermined percentage of the number of charges within a certain period is exceeded, and notifies the user according to the determination result. This improves user convenience while preventing excessive notifications to the user.

[0054] 2, when secondary auxiliary charging of the second battery 3 is started (step S9), the battery control unit 11 sets a second timer time t2 that specifies the maximum time for secondary auxiliary charging using the timer processing unit 15, and starts measuring the second timer time t2 (step S10). Furthermore, the battery control unit 11 determines whether the charge amount of the second battery 3 is equal to or less than a second threshold k2 based on the monitoring result of the second lower-level control unit 30 (step S11). If the charge amount is equal to or less than the second threshold k2 (step S11 / YES) and the second timer time t2 has not elapsed (step S12 / NO), the process proceeds to step S9, and the secondary auxiliary charging continues.

[0055] When the charge amount reaches the second threshold k2 due to the secondary auxiliary charging (NO in step S11), the battery control unit 11 stops the secondary auxiliary charging and proceeds to the processing in step S8. As a result, if the state where the predetermined operation is not being performed continues, as shown in Figures 5 and 6, after the secondary auxiliary charging, charging of the second battery 3 is not resumed until the charge amount of the second battery 3 falls below the third threshold k3. Through the above operations, the charge amount of the second battery 3 is maintained between the second threshold k2 and the third threshold k3 while the predetermined operation is not being performed, as shown in Figures 5 and 6.

[0056] The above operations are realized by the upper control unit 10 and the second lower control unit 30 operating in cooperation with each other. As described above, the communication state detection unit 18 detects the communication state between the upper control unit 10 and the second lower control unit 30. When the communication state detection unit 18 detects that the communication state between the upper control unit 10 and the second lower control unit 30 is abnormal, the upper control unit 10 causes the battery control unit 11 to not perform charge control of the second battery 3 based on the charge request from the second lower control unit 30, and charges the second battery 3 for a preset timer time.

[0057] If a communication abnormality occurs between the upper control unit 10 and the second lower control unit 30, it becomes impossible to control the charging of the second battery 3 using the monitoring results of the lower control unit, etc. In this embodiment, if a communication abnormality occurs, the upper control unit 10 charges the second battery 3 for a preset timer period, thereby preventing the charge level of the second battery 3 from decreasing excessively and causing the vehicle to become immobile.

[0058] Furthermore, the abnormality determination unit 17 counts the number of times charging has been performed based on charging requests from the lower-level control unit, and if the number of times charging has exceeded a predetermined value, it determines that an abnormality has occurred in the second battery 3. If charging has been performed frequently within a predetermined period, there is a high possibility that an abnormality (including battery life) has occurred in the second battery 3. Therefore, by determining the abnormal state based on the number of times charging has been performed based on charging requests within the predetermined period, an abnormality in the second battery 3 can be easily detected.

[0059] When an abnormality in the second battery 3 is detected, the battery control unit 11 performs a process of notifying the user of the vehicle of the abnormality in the second battery 3. A wide range of known processes can be applied to the process of notifying the user. For example, a process of transmitting notification information to a display device provided in the vehicle or a user terminal carried by the user can be applied. A wide range of known processes can be applied to the process of notifying the user, such as a process of transmitting notification information to a display device provided in the vehicle or a user terminal carried by the user.

[0060] [3. Threshold setting unit 14] As described above, the threshold setting unit 14 sets a first threshold k1 that specifies the charge amount that suppresses battery degradation, a second threshold k2 that is a value higher than the first threshold k1 and suppresses battery degradation, and a third threshold k3 that is a value lower than the first threshold k1 and can ensure the vehicle starts.

[0061] The first threshold k1 is preferably set to an appropriate value within a range of charge amounts that does not accelerate deterioration of the second battery 3 and that ensures vehicle startup. In this embodiment, the first threshold k1 is set based on the temperature of the second battery 3, making it possible to set a more appropriate first threshold k1. For example, when the second battery 3 is in a high temperature state, the first threshold k1 is set to a relatively low value, and when the second battery 3 is in a low temperature state, the first threshold k1 is set to a relatively high value. This makes it possible to set threshold values ​​that can suppress battery deterioration while avoiding supplemental charging as much as possible when the vehicle is performing a predetermined operation.

[0062] Furthermore, the second threshold k2 is preferably set to a value higher than the first threshold k1, and to a value that suppresses battery degradation while avoiding supplemental charging after the first supplemental charging as much as possible. In this embodiment, the second threshold k2 is set based on the temperature of the second battery 3, making it possible to set a more appropriate second threshold k2. For example, when the second battery 3 is in a high temperature state, the second threshold k2 is set to a relatively low value, and when the second battery 3 is in a low temperature state, the first threshold k1 is set to a relatively high value. This makes it possible to set thresholds that suppress battery degradation after the vehicle has completed a predetermined operation while avoiding supplemental charging as much as possible.

[0063] Furthermore, it is preferable that the third threshold k3 be set to a value lower than the first threshold k1, within a range of the charge amount of the second battery 3 that can ensure vehicle startup, and that avoids secondary auxiliary charging as much as possible. In this embodiment, the third threshold k3 is set based on the temperature of the second battery 3, allowing a more appropriate third threshold k3 to be set. For example, when the second battery 3 is at room temperature or higher, the third threshold k3 is set to a relatively low value, and when the second battery 3 is in a low temperature state, the third threshold k3 is set to a relatively high value. This makes it possible to set a threshold that can ensure vehicle startup and avoid auxiliary charging as much as possible. Note that the third threshold k3 may also be set based on the SOH (State of Health) of the second battery 3.

[0064] [4. Effect of charge control on suppressing deterioration of second battery 3] As described above, the battery control system 1 of this embodiment includes the battery control unit 11 that controls the charging of the first battery 2 and the second battery 3, and the charge amount monitoring unit 31 that functions as a battery monitoring unit that monitors the charge amounts of the first battery 2 and the second battery 3. When the vehicle is performing a predetermined operation, the battery control unit 11 charges the second battery 3 based on the monitoring result of the charge amount monitoring unit 31 so that the charge amount of the second battery 3 does not exceed the first threshold k1 that suppresses battery degradation, and when the vehicle has finished the predetermined operation, it performs primary supplementary charging to charge the second battery 3 up to the second threshold k2 that is higher than the first threshold k1.

[0065] This configuration suppresses deterioration of the second battery 3 and ensures the charge amount of the second battery 3 taking into consideration the dark current after the end of a predetermined operation and power consumption due to battery use. This makes it possible to both suppress battery deterioration and ensure an appropriate charge amount.

[0066] The predetermined operation includes at least one of the following: when the vehicle is running, when the first battery 2 is being charged, and when the power conversion unit 4 is operating while the vehicle is stopped. According to this configuration, when the vehicle is running, the first battery 2 is being charged, or the power conversion unit 4 is operating while the vehicle is stopped, even if the charge level of the second battery 3 decreases, the second battery 3 can be immediately supplementarily charged up to the first threshold k1, thereby ensuring an appropriate charge level while suppressing deterioration of the second battery 3.

[0067] Furthermore, the battery control unit 11 measures a first timer time t1, which is an estimated time until the charge level of the second battery 3 falls below a third threshold k3, which is lower than the first threshold k1, after the first auxiliary charging. When the first timer time t1 has elapsed, or when the charge level has fallen to the third threshold k3 before the first timer time t1 has elapsed based on the monitoring results of the charge level monitoring unit 31, the battery control unit 11 performs a secondary auxiliary charging to charge the second battery 3. With this configuration, even if the charge level of the second battery 3 decreases due to factors such as dark current after the first auxiliary charging, the second battery 3 can be recharged after the first timer time t1 has elapsed. This allows the second battery 3 to be charged while suppressing battery degradation due to excessive charging. Furthermore, setting the first timer time t1 based on the charge level of the second battery facilitates calculation of the first timer time t1.

[0068] Alternatively, the first timer time t1 may be set based on information obtained from a server, such as power information required for communications scheduled while the vehicle is stopped, or based on a combination of the information obtained from the server and the charge amount of the second battery 3. Exterior communication consumes power from the second battery 3, and for example, telematics communications may consume a large amount of power. Therefore, by setting the first timer time t1 based on information obtained from the server or based on a combination of the information obtained from the server and the charge amount of the second battery 3, it is possible to prevent the second battery 3 from being depleted while maintaining necessary communications.

[0069] Furthermore, if the battery control unit 11 detects, based on the monitoring results of the charge amount monitoring unit 31, that the charge amount of the second battery 3 is equal to or less than the third threshold value k3 before the first timer time t1 has elapsed, it performs the above-mentioned secondary supplementary charging as emergency supplementary charging. According to this configuration, if the charge level of the second battery 3 drops below the third threshold k3 at a timing earlier than the first timer time t1 due to the usage environment or condition of the second battery 3, the second battery 3 can be charged immediately, thereby avoiding a situation where the start-up of the vehicle is affected.

[0070] In addition, when emergency supplementary charging is performed, the battery control unit 11 determines whether or not the second battery 3 is experiencing a charging abnormality based on information about the second battery 3, and performs processing to notify the vehicle user of the charging abnormality based on the determination result. With this configuration, when emergency supplemental charging is performed, there is a possibility that the second battery 3 does not have the appropriate performance, for example, if the battery has deteriorated to the point where it can no longer maintain sufficient voltage or capacity, or if it has been replaced with a lower-performance battery. In such cases, it is possible to determine that a charging abnormality has occurred, and by notifying the user, this improves user convenience and also prevents excessive notifications to the user.

[0071] Furthermore, the battery control unit 11 does not perform primary supplementary charging of the second battery 3 when the charge amount of the first battery 2 is equal to or less than a predetermined threshold kmin. This configuration makes it possible to prevent the charge amount of the first battery 2 from being excessively reduced due to supplemental charging of the second battery 3, and makes it possible to perform appropriate charge control according to the vehicle conditions.

[0072] Furthermore, the battery control unit 11 does not perform secondary auxiliary charging of the second battery 3 when the charge amount of the first battery 2 is equal to or less than a predetermined threshold kmin. This configuration can prevent the charge amount of the first battery 2 from being excessively reduced due to supplemental charging of the second battery 3, and enables appropriate charge control according to the vehicle conditions.

[0073] The battery control system 1 also includes a vehicle information acquisition unit 13 that acquires vehicle information, including the open / closed state of at least one of the opening / closing members of the vehicle's hood, doors, and luggage compartment, and the battery control unit 11 does not perform primary supplementary charging until a predetermined waiting time has elapsed if the opening / closing member is opened within a predetermined period after the vehicle is powered off. This configuration can prevent auxiliary charging of the second battery 3 from interfering with work on the vehicle, improving the ease of vehicle maintenance.

[0074] [5. Effect of cooperative control on the second battery 3] The battery control system 1 of this embodiment includes a host control unit 10 that controls charging of the first battery 2 and the second battery 3, and a second lower control unit 30 that monitors the second battery 3. The host control unit 10 includes a battery information acquisition unit 12 that acquires battery information about the batteries 2 and 3, a vehicle information acquisition unit 13 that acquires vehicle information about the vehicle, a threshold setting unit 14 that sets a threshold that defines the charge amount of the second battery 3 based on the battery information, and a charge feasibility determination unit 16 that determines whether the second battery 3 can be charged based on the vehicle information and transmits the determination result and the threshold to the second lower control unit 30. The second lower control unit 30 includes a charge amount monitoring unit 31 that monitors the charge amount of the second battery 3, and a charge necessity determination unit 32 that transmits a charge request for the second battery 3 to the host control unit 10 when the determination result indicates that the second battery 3 is chargeable and the charge amount is equal to or less than thresholds k1 and k2.

[0075] According to this configuration, the second lower-level control unit 30 monitors the second battery 3 and determines whether charging is necessary, which reduces the time and power consumption required for this processing compared to when the higher-level control unit 10 performs this processing. Furthermore, the higher-level control unit 10 performs processing related to cooperative control between the higher-level control unit 10 and the second lower-level control unit 30, such as setting the thresholds k1 and k2, so that appropriate thresholds k1 and k2 can be set efficiently. This enables faster control related to battery charging, saves power, and ensures an appropriate amount of charge for the battery.

[0076] The battery information also includes the temperature of the second battery 3, and the threshold setting unit 14 sets the thresholds k1 and k2 based on the temperature of the second battery 3. According to this configuration, the appropriate charge amount varies depending on the temperature of the second battery 3, so by setting the thresholds k1 and k2 based on the temperature of the second battery 3, it becomes easier to set thresholds that ensure an appropriate charge amount while minimizing supplementary charging. Furthermore, the second lower-level control unit 30 monitors whether the charge amount of the second battery 3 has fallen below a third threshold k3 using the charge amount monitoring unit 31 when the second battery 3 is not being charged, and when the charge amount has fallen below the third threshold k3, the charge necessity determining unit 32 transmits a request to charge the second battery 3 to the upper-level control unit 10. By setting the threshold value k3 based on the temperature of the second battery 3, the threshold value setting unit 14 can ensure vehicle startup and makes it easier to set a threshold value that ensures an appropriate charge amount while minimizing supplementary charging.

[0077] In addition, in the upper control unit 10, the vehicle information includes the open / closed state of at least one of the opening / closing members of the vehicle's hood, doors, and luggage compartment, and the charging feasibility determination unit 16 does not determine that the second battery 3 can be charged until a predetermined waiting time has elapsed if the opening / closing member is opened within a predetermined period after the vehicle has completed a predetermined operation. This configuration can prevent charging of the second battery 3 from interfering with work on the vehicle, improving the ease of vehicle maintenance.

[0078] The predetermined operation includes at least one of running the moving body, charging the first battery 2 (and operating the power conversion unit 4 while the moving body is not running (while the vehicle is parked)). According to this configuration, when the opening / closing member is opened after at least one of the following conditions is met: the vehicle is running, the first battery 2 is being charged, and the power conversion unit 4 is operating while the vehicle is stopped; this prevents charging of the second battery 3 from interfering with work on the vehicle, thereby improving the maintainability of the vehicle.

[0079] In addition, a communication status detection unit 18 is provided to detect the communication status between the upper control unit 10 and the second lower control unit 30, and if the communication status is abnormal, the upper control unit 10 does not perform charging control of the second battery 3 based on a charging request from the second lower control unit 30, but charges the second battery 3 for a preset timer time. According to this configuration, if a communication abnormality occurs between the upper control unit 10 and the second lower control unit 30, it becomes impossible to control charging of the second battery 3 using the monitoring results of the second lower control unit 30. When a communication abnormality occurs, the upper control unit 10 charges the second battery 3 for a preset timer period, thereby preventing the vehicle from becoming immobile.

[0080] In addition, the charge amount monitoring unit 31 constantly monitors the charge amount of the second battery 3 while the second lower control unit 30 is awake, and intermittently monitors the charge amount of the second battery 3 while the second lower control unit 30 is asleep. This configuration enables real-time charge management during wake-up and power-saving charge management during sleep, enabling efficient operation.

[0081] The upper control unit 10 also includes an abnormality judgment unit 17 that judges whether at least the second battery 3 out of the first battery 2 and the second battery 3 is in an abnormal state. The abnormality judgment unit 17 counts the number of charges based on a charge request from the second lower control unit 30 within a predetermined period, and judges that an abnormality has occurred in the second battery 3 when the number of charges exceeds a predetermined value. According to this configuration, if charging is performed frequently within a specified period, there is a high possibility that an abnormality has occurred in the battery. Therefore, an abnormality in the second battery 3 can be easily detected by determining the abnormal state based on the number of charges based on charging requests within the specified period.

[0082] The processing of the battery control unit 11 can be referred to as a battery control step, the processing of the battery information acquisition unit 12 can be referred to as a battery information acquisition step, the processing of the vehicle information acquisition unit 13 can be referred to as a vehicle information acquisition step, the processing of the threshold setting unit 14 can be referred to as a threshold setting step, the processing of the timer processing unit 15 can be referred to as a timer processing step, the processing of the charging feasibility determination unit 16 can be referred to as a charging feasibility determination step, the processing of the abnormality determination unit 17 can be referred to as an abnormality determination step, the processing of the communication status detection unit 18 can be referred to as a communication status detection step, the processing of the charging amount monitoring unit 31 can be referred to as a charging amount monitoring step, and the processing of the charging necessity determination unit 32 can be referred to as a charging necessity determination step.

[0083] 6. Other Embodiments The above embodiment is merely one embodiment of the present invention, and any modifications and applications are possible without departing from the spirit of the present invention.

[0084] For example, in cold regions or at night in winter, the battery temperature may drop below freezing, and when the battery temperature is low, the accuracy of detecting the battery charge level decreases. FIG. 7 is a diagram for explaining the first modification, showing an example of the change over time in the charge amount of the second battery 3 when the power-off state shown in FIG. 5 continues for a long period of time. The solid line fa in Fig. 7 shows the change characteristics of the actual charge amount of the second battery 3 detected when the battery temperature detection accuracy is in a relatively high temperature range. The dashed-dotted line fb in Fig. 7 shows the change characteristics of the actual charge amount of the second battery 3 when the battery temperature detection accuracy is in a relatively low temperature range while the vehicle is stopped. As shown in Figure 7, the charge amount fb in the low temperature range is lower than the charge amount fa when the temperature is not in the low temperature range, and there is a risk that the actual charge amount of the second battery 3 will decrease excessively, for example, will fall below the third threshold k3.

[0085] Therefore, first, when the temperature is in a predetermined range where the detection accuracy of the charge amount of the second battery 3 is relatively low, a fixed timer time t1b (see Figure 7) is set to a timing before the point at which the charge amount of the second battery 3 drops excessively (for example, the point at which it becomes equal to or less than the third threshold k3). In the example shown in FIG. 7, the relationship is fixed timer time t1b<first timer time t1, but the relationship is not limited to this, and there may be a relationship where fixed timer time t1b>first timer time t1.

[0086] Then, as illustrated in FIG. 7, after the supplementary charging consisting of the primary supplementary charging and the secondary supplementary charging, if the temperature of the second battery 3 is within a predetermined temperature range in which the accuracy of detecting the charge amount of the second battery 3 becomes relatively low, the battery control unit 11 performs the secondary supplementary charging of the second battery 3 as shown by the two-dot chain line fc in FIG. 7 after the shorter timer time of the first timer time t1 and the fixed timer time t1b has elapsed. This allows the second battery 3 to be forcibly charged before the charge level drops excessively in a temperature range where the accuracy of detecting the charge level of the second battery 3 is relatively low, thereby preventing the charge level of the second battery 3 from dropping excessively and preventing the battery from running out in cold weather, for example.

[0087] FIG. 8 is a diagram showing an example of the change over time in the charge amount of the second battery 3, which is provided for explaining the second and third modified examples. In the second modification, when the temperature of the second battery 3 is within a predetermined temperature range where the detection accuracy of the charge amount of the second battery 3 becomes relatively low and the vehicle is performing a predetermined operation, the battery control unit 11 performs fixed voltage charging of the second battery 3 as shown in Fig. 8. Fixed voltage charging can suppress voltage fluctuations of the second battery 3 and stabilize the state of charge. In the second modification, when the temperature of the second battery 3 is within the above-mentioned predetermined temperature range and the moving body has completed a predetermined operation, the battery control unit 11 charges the second battery 3 for a preset first fixed timer time ta, as shown in Fig. 8. This ensures that the second battery 3 has a sufficient amount of charge even in a predetermined temperature range where the detection accuracy of the amount of charge of the second battery 3 is relatively low, and prevents problems from occurring when starting the vehicle, etc.

[0088] Next, after the first fixed timer time ta has elapsed and a predetermined second fixed timer time tb has elapsed, the battery control unit 11 charges the second battery 3 for the first fixed timer time ta. In this way, charging for the first fixed timer time ta and stopping charging for the second fixed timer time tb are repeated while the temperature of the second battery 3 remains within the predetermined temperature range and the vehicle is not in a predetermined operation. By appropriately setting the first fixed timer time ta and the second fixed timer time tb, it is possible to avoid an excessive decrease in the charge level of the second battery 3 and ensure a sufficient charge level, regardless of the detected charge level, thereby preventing problems with starting the vehicle, etc.

[0089] In the third modification, when the communication state detection unit 18 detects that the communication state is abnormal and the vehicle is performing a predetermined operation, the battery control unit 11 performs fixed voltage charging of the second battery 3, as shown in Fig. 8. Fixed voltage charging can suppress voltage fluctuations in the second battery 3 and stabilize the charging state. In the third modification, when the communication state detection unit 18 detects that the communication state is abnormal and the vehicle has finished a predetermined operation, the battery control unit 11 charges the second battery 3 for a preset first fixed timer time ta, as shown in Fig. 8. This ensures that the second battery 3 is sufficiently charged when control based on the charge amount is not possible due to a communication abnormality, and prevents problems with starting the vehicle, etc.

[0090] Furthermore, in the above embodiment, if a failure is detected on the first battery 2 side, or if an abnormality is detected by the abnormality judgment unit 17 and the communication status detection unit 18, etc., and a situation occurs in which charging of the second battery 3 is not possible, a signal prohibiting charging of the second battery 3 may be transmitted from the upper control unit 10 to the second lower control unit 30, and charging of the second battery 3 may be prohibited until a release signal is sent from the upper control unit 10 to the second lower control unit 30. In this case, for example, the battery control unit 11 may transmit a signal to the charge amount monitoring unit 31, which functions as a battery monitoring unit, to prohibit charging of the second battery 3, and charging of the second battery 3 may be prohibited until the battery control unit 11 sends a release signal to the charge amount monitoring unit 31.

[0091] Furthermore, when the battery control unit 11 does not perform supplemental charging, the exterior communication unit 5 may impose a communication restriction depending on the reason for not performing supplemental charging. Reasons for not performing supplemental charging include when the charge level of the first battery 2 is equal to or lower than a predetermined value, when an opening / closing member such as the hood is opened within a predetermined period after the vehicle power is turned off, and when the charge level of the first battery 2 is equal to or lower than a predetermined threshold kmin. External vehicle communication consumes power from the second battery 3, and power consumption can be high for telematics communication, for example. Therefore, in an environment where supplemental charging is not possible, communication restrictions can be imposed depending on the reason for prohibiting supplemental charging, such as when the charge level of the first battery 2 is below a predetermined value, thereby preventing consumption of the second battery 3 while maintaining necessary communication.

[0092] The configuration of the battery control system 1 shown in Fig. 1 is an example, and the configuration may be changed as appropriate. For example, the first battery 2 and the second battery 3 may be batteries other than lithium-ion batteries. Furthermore, the configuration of the battery control unit 11 and other components is not limited to being configured to be completed within the vehicle. For example, at least a portion of the processing performed by the battery control unit 11 and other components may be performed by a device outside the vehicle, such as a server.

[0093] 1 is a schematic diagram showing the configuration of the battery control system 1 divided by main processing content to facilitate understanding of the present invention, but the battery control system 1 may be divided into other categories. Furthermore, the processing of each component may be executed by one hardware unit or multiple hardware units. Furthermore, the processing of each component may be executed by one program or multiple programs.

[0094] Although the program for implementing the battery control method of the present invention has been described as being recorded in a memory included in the battery control system 1, the program may be acquired from an external device via communication. The program may also be recorded on a computer-readable recording medium. The recording medium may be a magnetic or optical recording medium, or a semiconductor memory device.

[0095] 7. Configurations Supported by the Above Embodiments The above embodiment is a specific example of the following configuration.

[0096] (Configuration 1) A battery control system mounted on a mobile body, comprising: a first battery that stores power for driving a power unit; a power conversion unit that converts the power stored in the first battery into a predetermined power; a second battery that is charged with the predetermined power; a battery control unit that controls the charging of the first battery and the second battery; and a battery monitoring unit that monitors the charge amounts of the first battery and the second battery, wherein, when the mobile body is performing a predetermined operation, the battery control unit charges the second battery based on the monitoring results of the battery monitoring unit so that the charge amount of the second battery does not exceed a first threshold that suppresses battery deterioration, and when the mobile body has completed the predetermined operation, the battery control system performs primary auxiliary charging to charge the second battery to a second threshold that is higher than the first threshold. This configuration suppresses deterioration of the second battery and ensures the charge amount of the second battery by taking into account the dark current after the end of a predetermined operation and power consumption due to battery use. This makes it possible to suppress battery deterioration and ensure an appropriate charge amount at the same time.

[0097] (Configuration 2) The battery control system according to Configuration 1, wherein the predetermined operation includes at least one of the following: while the moving body is traveling, while the first battery is being charged, and while the power conversion unit is operating while the moving body is stopped. According to this configuration, when the mobile body is traveling, the first battery is being charged, or the power conversion unit is operating while traveling is stopped, even if the charge level of the second battery decreases, the second battery can be immediately supplementarily charged to the first threshold, thereby ensuring an appropriate charge level while suppressing deterioration of the second battery.

[0098] (Configuration 3) The battery control system of configuration 1 or 2, wherein the battery control unit, after performing the primary auxiliary charging, measures a first timer time, which is an estimated time until the charge amount of the second battery becomes equal to or less than a third threshold value that is lower than the first threshold value, and performs a secondary auxiliary charging to charge the second battery when the first timer time has elapsed, or when, based on the monitoring result of the battery monitoring unit, the charge amount has decreased to the third threshold value before the first timer time has elapsed. With this configuration, even if the charge level of the second battery decreases due to dark current or other factors after primary supplemental charging, the second battery can be recharged after the first timer time has elapsed or if the charge level has decreased to the third threshold before the first timer time has elapsed. This makes it possible to charge the second battery while suppressing battery degradation due to excessive charging.

[0099] (Configuration 4) A battery control system according to configuration 3, wherein if the battery control unit detects that the charge amount is equal to or less than the third threshold based on the monitoring result of the battery monitoring unit before the first timer time has elapsed, the battery control unit performs the secondary supplementary charging as an emergency supplementary charging. According to this configuration, if the charge level of the second battery drops below the third threshold earlier than the first timer time due to the usage environment or condition of the second battery, the second battery can be charged immediately, thereby avoiding a situation where the start-up of the mobile object is affected.

[0100] (Configuration 5) A battery control system according to configuration 4, wherein the battery control unit, when performing the emergency supplementary charging, determines whether the second battery has a charging abnormality based on information about the second battery, and performs processing to notify the user of the mobile body of the charging abnormality depending on the determination result. With this configuration, when emergency supplemental charging is performed, the battery may not have the appropriate performance, for example, if the battery has deteriorated to the point where it can no longer maintain sufficient voltage or capacity, or if it has been replaced with a lower-performance battery. In such cases, it can be determined that a charging abnormality has occurred, and by notifying the user, this improves user convenience and also prevents excessive notifications to the user.

[0101] (Configuration 6) The battery control system according to any one of configurations 1 to 5, wherein the battery control unit does not perform the primary auxiliary charging when the charge amount of the first battery is equal to or less than a predetermined value. This configuration makes it possible to prevent the charge amount of the first battery from being excessively reduced due to supplemental charging of the second battery, and makes it possible to perform appropriate charge control according to the state of the mobile body.

[0102] (Configuration 7) The battery control system according to Configuration 4, wherein the battery control unit does not perform the secondary auxiliary charging when the charge amount of the first battery is equal to or less than a predetermined value. This configuration can prevent the charge amount of the first battery 2 from being excessively reduced due to supplemental charging of the second battery 3, and enables appropriate charge control according to the vehicle conditions.

[0103] (Configuration 8) A battery control system according to any one of configurations 1 to 6, wherein the mobile body is a vehicle and is provided with a vehicle information acquisition unit that acquires vehicle information, which is information about the vehicle, and the vehicle information includes the open / closed state of at least one of the opening / closing members of the hood, doors, and luggage compartment of the vehicle, and the battery control unit 11 does not perform the primary supplementary charging until a predetermined waiting time has elapsed if the opening / closing member is opened within a predetermined period after the vehicle is powered off. This configuration makes it possible to prevent auxiliary charging of the second battery from interfering with work on the vehicle, improving maintainability.

[0104] (Configuration 9) The battery control system 1 of any one of configurations 3 to 5 further comprises a battery temperature acquisition unit that acquires the temperature of the second battery, and if, after the primary auxiliary charging or the secondary auxiliary charging, the temperature of the second battery is within a predetermined temperature range in which the detection accuracy of the charge amount of the second battery becomes relatively low, the battery control unit performs the secondary auxiliary charging after the shorter timer time of the first timer time or a predetermined fixed timer time corresponding to the predetermined temperature range has elapsed. According to this configuration, it is possible to avoid a situation in which the charge level of the second battery drops excessively when the temperature is within a predetermined range in which the accuracy of detecting the charge level of the second battery is relatively low, thereby preventing the so-called dead battery.

[0105] (Configuration 10) A battery control system according to any one of configurations 1 to 9, further comprising a battery temperature acquisition unit that acquires the temperature of the second battery, wherein the battery control unit performs fixed voltage charging of the second battery when the temperature of the second battery is within a predetermined temperature range in which the detection accuracy of the charge amount of the second battery is relatively low and the mobile body is performing the predetermined operation, and when the temperature of the second battery is within the predetermined temperature range and the mobile body has completed the predetermined operation, charges the second battery for a predetermined first fixed timer time. According to this configuration, the second battery can be sufficiently charged even in a predetermined temperature range where the accuracy of detecting the charge amount of the second battery is relatively low, thereby preventing problems such as starting up the mobile body.

[0106] (Configuration 11) A battery control system as described in any one of configurations 1 to 10, comprising a communication status detection unit that detects the communication status between the battery control unit and the battery monitoring unit, wherein the battery control unit performs fixed voltage charging of the second battery when the communication status is detected to be abnormal and the vehicle is performing a predetermined operation, and when the communication status is detected to be abnormal and the mobile body has completed the predetermined operation, charges the second battery for a predetermined first fixed timer time. According to this configuration, when control based on the charge amount cannot be performed due to a communication abnormality, the second battery can be sufficiently charged, and problems such as starting up the mobile object can be prevented.

[0107] (Configuration 12) A battery control system described in any one of configurations 6, 7, and 8, wherein the vehicle is provided with an external communication unit that communicates with a server outside the vehicle, and the external communication unit restricts communication depending on the reason for not performing supplemental charging when the battery control unit does not perform supplemental charging. With this configuration, communication outside the vehicle consumes power from the second battery, and power consumption can be high, for example, for communications such as telematics. Therefore, in an environment where supplemental charging is not possible, communication restrictions can be imposed depending on the reason for prohibiting supplemental charging, such as when the charge level of the first battery is below a predetermined value, thereby preventing battery drain while maintaining necessary communications.

[0108] (Configuration 13) The vehicle is equipped with an external communication unit that communicates with a server outside the vehicle, and the battery control unit measures a first timer time after performing the primary auxiliary charging, and performs a secondary auxiliary charging to charge the second battery when the first timer time has elapsed, or when the charge amount has decreased to the third threshold before the first timer time has elapsed based on the monitoring result of the battery monitoring unit, and the first timer time is set based on information obtained from the server, or is set based on a combination of information obtained from the server and the charge amount of the second battery 3. A battery control system described in any one of configurations 1 to 12. With this configuration, communication outside the vehicle consumes power from the second battery, and power consumption can be high, for example, in communications for telematics, etc. Therefore, by setting the first timer time based on information obtained from the server, or based on a combination of information obtained from the server and the amount of charge in the second battery 3, it is possible to prevent battery consumption while maintaining necessary communications.

[0109] (Configuration 14) A battery control method for a mobile body comprising a first battery that stores power for driving a power unit, a power conversion unit that converts the power stored in the first battery to a predetermined power, a second battery that is charged with the predetermined power, a battery control unit that controls the charging of the first battery and the second battery, and a battery monitoring unit that monitors the charge amounts of the first battery and the second battery, wherein when the mobile body is performing a predetermined operation, the battery control unit charges the second battery based on the monitoring results of the battery monitoring unit so that the charge amount of the second battery does not exceed a first threshold that suppresses battery deterioration, and when the mobile body has completed the predetermined operation, performs primary auxiliary charging to charge the second battery to a second threshold that is higher than the first threshold. This method suppresses deterioration of the second battery and ensures the charge amount of the second battery by taking into account the dark current after the end of a predetermined operation and power consumption due to battery use. This makes it possible to suppress battery deterioration and ensure an appropriate charge amount at the same time. [Explanation of symbols]

[0110] 1...battery control system, 2...first battery, 3...second battery, 4...power conversion unit, 5...external vehicle communication unit, 11...battery control unit, 12...battery information acquisition unit, 13...vehicle information acquisition unit (battery temperature acquisition unit), 14...threshold setting unit, 15...timer processing unit, 16...charging feasibility determination unit, 17...abnormality determination unit, 18...communication status detection unit, 20...lower control unit (first lower control unit), 21, 31...charging amount monitoring unit (battery monitoring unit), 22, 32...charging necessity determination unit, 30...lower control unit (second lower control unit).

Claims

1. In a battery control system mounted on a mobile object, a first battery that stores electric power for driving the power unit; a power conversion unit that converts the power stored in the first battery into a predetermined power; a second battery that is charged with the predetermined power; a battery control unit that controls charging of the first battery and the second battery; a battery monitoring unit that monitors the charge amounts of the first battery and the second battery, The battery control unit When the moving object is performing a predetermined operation, charging the second battery based on a monitoring result of the battery monitoring unit so that a charge amount of the second battery does not exceed a first threshold that suppresses battery degradation; When the moving body has completed a predetermined operation, a primary auxiliary charge is performed to charge the second battery up to a second threshold value that is higher than the first threshold value. Battery control system.

2. The predetermined operation includes at least one of a state in which the moving body is running, a state in which the first battery is being charged, and a state in which the power conversion unit is operating while the moving body is stopped. The battery control system of claim 1 .

3. After performing the primary auxiliary charging, the battery control unit measures a first timer time which is an estimated time until the charge amount of the second battery becomes equal to or less than a third threshold which is lower than the first threshold, and performs secondary auxiliary charging to charge the second battery when the first timer time has elapsed or when, based on a monitoring result of the battery monitoring unit, the charge amount has decreased to the third threshold before the first timer time has elapsed. The battery control system of claim 1 .

4. When the battery control unit detects that the charge amount is equal to or less than the third threshold based on the monitoring result of the battery monitoring unit before the first timer time has elapsed, the battery control unit performs the secondary supplementary charging as emergency supplementary charging. The battery control system according to claim 3 .

5. When the emergency supplementary charging is performed, the battery control unit determines whether or not the second battery has a charging abnormality based on the information about the second battery, and performs processing to notify the user of the mobile body of the charging abnormality according to the determination result. The battery control system according to claim 4 .

6. The battery control unit does not perform the primary auxiliary charging when the charge amount of the first battery is equal to or less than a predetermined value. The battery control system of claim 1 .

7. the battery control unit does not perform the secondary auxiliary charging when the charge amount of the first battery is equal to or less than a predetermined value. The battery control system according to claim 4 .

8. the moving body is a vehicle, a vehicle information acquisition unit that acquires vehicle information that is information about the vehicle; the vehicle information includes an open / close state of at least one of an opening / closing member of a hood, a door, and a luggage compartment of the vehicle; When the opening / closing member is opened within a predetermined period after the power supply of the vehicle is turned off, the battery control unit does not perform the primary auxiliary charging until a predetermined waiting time has elapsed. The battery control system of claim 1 .

9. a battery temperature acquisition unit that acquires a temperature of the second battery; After the primary auxiliary charging or the secondary auxiliary charging, if the temperature of the second battery is within a predetermined temperature range in which the detection accuracy of the charge amount of the second battery becomes relatively low, the battery control unit performs the secondary auxiliary charging after a shorter timer time has elapsed between the first timer time and a predetermined fixed timer time corresponding to the predetermined temperature range. The battery control system according to claim 3 .

10. a battery temperature acquisition unit that acquires a temperature of the second battery; The battery control unit When the temperature of the second battery is within a predetermined temperature range in which the detection accuracy of the charge amount of the second battery becomes relatively low and the moving object is performing the predetermined operation, the second battery is charged to a fixed voltage; When the temperature of the second battery is within the predetermined temperature range and the moving body has completed a predetermined operation, the second battery is charged for a first fixed timer time that is set in advance. The battery control system of claim 1 .

11. a communication state detection unit that detects a communication state between the battery control unit and the battery monitoring unit; The battery control unit charges the second battery at a fixed voltage when the communication state is detected as abnormal and the vehicle is performing a predetermined operation, and charges the second battery for a preset first fixed timer time when the communication state is detected as abnormal and the vehicle has finished the predetermined operation. The battery control system of claim 1 .

12. the vehicle includes an exterior communication unit that communicates with a server outside the vehicle; When the battery control unit does not perform supplemental charging, the external communication unit restricts communication depending on the reason for not performing supplemental charging.

9. A battery control system according to any one of claims 6, 7 and 8.

13. the vehicle includes an exterior communication unit that communicates with a server outside the vehicle; the battery control unit measures a first timer time after performing the primary supplementary charging; When the first timer time has elapsed, or when the charge amount has decreased to the third threshold value before the first timer time has elapsed based on the monitoring result of the battery monitoring unit, a secondary supplementary charging is performed to charge the second battery; The first timer time is set based on information obtained from the server, or based on a combination of information obtained from the server and the amount of charge of the second battery. The battery control system of claim 1 .

14. a first battery that stores electric power for driving the power unit; a power conversion unit that converts the power stored in the first battery into a predetermined power; a second battery that is charged with the predetermined power; a battery control unit that controls charging of the first battery and the second battery; a battery monitoring unit that monitors the charge amounts of the first battery and the second battery, The battery control unit When the moving object is performing a predetermined operation, charging the second battery based on a monitoring result of the battery monitoring unit so that a charge amount of the second battery does not exceed a first threshold that suppresses battery degradation; When the moving body has completed a predetermined operation, a primary auxiliary charge is performed to charge the second battery up to a second threshold value that is higher than the first threshold value. Battery control method.

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