Energy supply control device

Abstract

Energy supply control device (40) that estimates a full charge capacity of a battery (12; 22) mounted in a vehicle, the energy supply control device comprising: a determination unit (41) designed to determine whether there is a need to correct a currently estimated full charge capacity when a state of charge of the battery (12; 22) is equal to or greater than a first predetermined value at a time when the power supply from the vehicle is switched OFF, wherein the determination unit (41) is set up, to estimate a deterioration state of the full charge capacity of the battery (12; 22), and is set up to determine whether there is a need to correct the full charge capacity based on the estimated deterioration state, and to estimate the deterioration state based on whether the ratio of a time period in which a battery temperature (12; 22) becomes equal to or lower than a predetermined temperature to a time period from the start of use obtained from predetermined battery temperature information is equal to or less than a sixth predetermined value; an energy transfer unit (42) configured to transfer a predetermined amount of energy from battery (12; 22) to another battery (12; 22) when the determining unit (41) determines that there is a need to correct the currently estimated full charge capacity; and a capacity estimation unit (43) configured to perform a predetermined full charge capacity estimation process at the battery (12; 22) at a time when the vehicle's power supply is switched ON after the energy transfer by the energy transfer unit (42) or during the energy transfer by the energy transfer unit (42).

Description

BACKGROUND OF THE INVENTION 1. Technical Field

[0001] The present invention relates to a power supply control device that estimates the full charge capacity of a battery installed in a vehicle. 2. Description of the state of the art

[0002] The unexamined Japanese patent application with publication number 2013-101072 (JP 2013-101072 A) discloses a technique for accurately estimating the full-charge capacity of a battery. In this technique, each time charging from an external power supply to a vehicle is performed, the battery's full-charge capacity is calculated using a current integration method, and a new full-charge capacity is learned by adding a previously learned full-charge capacity to a currently calculated full-charge capacity in a predetermined ratio. Accordingly, it is possible to reduce the influence of sensor or sensing errors and to accurately estimate the battery's full-charge capacity.Patent JP 2017-91852A describes a control unit for a power supply system that determines and learns the full charge capacity of a lithium-ion battery based on the charging / discharging current flowing between it and a lead-acid battery, without requiring external charging or discharging of the vehicle. Patent CN 107783051A describes a system that uses OCV-SOC curves and adaptation tables to determine the current full charge capacity for both a "healthy" battery (i.e., a battery with a low number of cycles) and an aged battery (i.e., a battery with a high number of cycles), taking into account the OCV value, temperature, and number of charge cycles. Patent US 2017 / 0274794A1 describes a device for determining battery status, which optionally determines the state of charge based on the full charge capacity or the discharge capacity and includes corresponding estimation and integration units for this purpose.Patent JP 2016 - 181 991 A describes a charger which uses a control circuit to regulate a cell balancing process in order to equalize the voltages or capacities of several batteries in a battery pack even when highly accurate OCV values ​​are not available. SUMMARY OF THE INVENTION

[0003] In a battery with a flat region in a state-of-charge (SOC) characteristic curve of an open-circuit voltage (OCV) (compare Fig. 2) For batteries like lithium iron phosphate, it is conceivable to calculate the state of charge (SOC) using a current integration method, since it is difficult to determine a state of charge (SOC) based on an open-circuit voltage (OCV). Here, it is desirable to acquire the latest possible value by increasing the frequency at which an estimation process is performed, because the full charge capacity required to calculate the SOC using the current integration method is a value that changes as the battery degrades.

[0004] However, in a scheme described in JP 2013-101072 A, the full-charge capacity estimation process is only performed under limited circumstances, such as when an external charge is being carried out. Furthermore, there is a need to ensure a large state-of-charge (SOC) difference (ΔSOC) before and after charging to accurately estimate the full-charge capacity, but in the scheme described in JP 2013-101072 A, ensuring ΔSOC is insufficient because external charging is situation-dependent. Therefore, there is room for improvement in the timing or scheme for performing the full-charge capacity estimation process.

[0005] The present invention provides a power supply control device capable of performing a process for estimating a full charge capacity of a battery at a suitable time, or using a suitable scheme.

[0006] One aspect of the present invention relates to a power supply control device that estimates the full charge capacity of a battery installed in a vehicle.The power supply control device comprises a determination unit configured to determine whether there is a need to correct a currently estimated full charge capacity when a battery's state of charge is equal to or greater than a first predetermined value at a time when the vehicle's power supply is switched OFF; a power transfer unit configured to transfer a predetermined amount of energy from the battery to another battery when the determination unit determines that there is a need to correct the currently estimated full charge capacity; and a capacity estimation unit configured to perform a predetermined full charge capacity estimation process at the battery at a time when the vehicle's power supply is switched ON, either after the power transfer by the power transfer unit or during the power transfer by the power transfer unit.

[0007] In the energy supply control device according to the aspect of the present invention, the determination unit can be configured to determine whether there is a need to correct the full charge capacity based on whether a predetermined number of days have passed since the day on which the full charge capacity of the battery was last estimated by the capacity estimation unit.

[0008] In the energy supply control device according to the aspect of the present invention, the determining unit can be configured to estimate a deterioration state of the battery's full charge capacity and can be configured to determine whether there is a need to correct the full charge capacity based on the estimated deterioration state.

[0009] In the power supply control device according to the aspect of the present invention, the determination unit can be configured to estimate the deterioration state based on whether a deviation between a full charge capacity obtained from a predetermined aging deterioration curve and the full charge capacity estimated by the capacity estimation unit is equal to or greater than a second predetermined value.

[0010] In the power supply control device according to the aspect of the present invention, the determining unit can be configured to estimate the deterioration state based on whether the ratio of a time period in which a battery temperature becomes equal to or lower than a predetermined temperature to a time period from the start of use, obtained from predetermined battery temperature information, is equal to or less than a sixth predetermined value.

[0011] In the energy supply control device according to the aspect of the present invention, the energy transfer unit can be arranged to transfer the predetermined energy from the battery to the other battery when an open-circuit voltage of the battery is higher by a third predetermined value or more than an open-circuit voltage of the other battery.

[0012] In the energy supply control device according to the aspect of the present invention, the transmission unit can be configured to terminate the energy transmission when the state of charge of the battery becomes equal to or less than a fourth predetermined value less than the first predetermined value, or when a current value discharged from the battery becomes equal to or less than a fifth predetermined value.

[0013] In the energy supply control device according to the aspect of the present invention, the capacity estimation unit can be configured to perform the full charge capacity estimation process at a time when the vehicle's energy supply is switched ON, without the determination unit performing the determination if the battery's state of charge is less than the first predetermined value.

[0014] In the energy supply control device according to the aspect of the present invention, the energy transfer unit can be configured to carry out a charging process of the battery with at least a portion of the energy that was transferred to the other battery when the estimation of the full charge capacity due to the energy transfer of the battery is complete.

[0015] According to the aspect of the present invention, it is possible to carry out a process for estimating a full charge capacity of a battery at a suitable time or using a suitable scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Features, advantages and technical and industrial significance of the exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same numbers denote the same elements, and wherein: Fig. 1 a diagram showing a schematic configuration example of a power supply system comprising a power supply control device according to a first embodiment; Fig. 2 shows a graph illustrating an example of the SOC-OCV characteristics of a lithium-ion battery; Fig. 3 shows a flowchart illustrating the sequence of a process relating to estimating a full charge capacity of a battery, which is carried out by a power supply control device according to the first embodiment; Fig. 4A shows a graph illustrating an example of an ideal curve of battery capacity degradation; Fig. 4B shows a graph illustrating an example of an ideal curve of battery capacity degradation; Fig. 4C shows a graph illustrating an example of an ideal curve of battery capacity degradation; Fig. 5 shows a diagram illustrating a schematic configuration example of a power supply system comprising a power supply control device according to a second embodiment; Fig. Figure 6A shows a flowchart illustrating a procedure of a process relating to estimating a full charge capacity of a battery, which is carried out by a power supply control device according to a second embodiment; Fig. 6B shows a flowchart illustrating the sequence of a process relating to estimating a full charge capacity of a battery, which is carried out by a power supply control device according to the second embodiment and a fourth embodiment; Fig. 7 shows a flowchart illustrating the sequence of a process relating to estimating a full charge capacity of a battery, which is carried out by a power supply control device according to a third embodiment; Fig. 8 shows a diagram illustrating an example of the aging deterioration characteristics when the ambient temperature of a battery has changed; Fig. 9 shows a table illustrating an example in which a presence time was calculated for each temperature of the battery; Fig. 10 shows a table illustrating an example in which a presence frequency was calculated for each temperature of the battery; Fig. Figure 11 shows a graph that shows a presence frequency for each temperature of the battery in Fig. 10 illustrates; and Fig. Figure 12 shows a flowchart illustrating the sequence of a process relating to estimating a full charge capacity of a battery, which is carried out by a power supply control device according to a fourth embodiment. DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES Overview

[0017] The power supply control device of the present invention transfers energy from one battery, where a full charge capacity correction is required, to another battery and reduces the energy to a predetermined state of charge (SOC) at the time when the vehicle's power supply is switched off. The battery's full charge capacity, which is the correction target, is calculated using a current integration method with a large SOC width at the time the vehicle's power supply is switched on. Accordingly, it is possible to estimate the full charge capacity with high accuracy. First example configuration

[0018] Fig. Figure 1 shows a diagram illustrating a schematic configuration example of a power supply system 1 for a vehicle, comprising a power supply control device 40 according to a first embodiment of the present invention. The Fig. 1 The illustrated power supply system 1 comprises a first power supply system comprising a first DCDC converter (hereinafter referred to as a “first DDC”) 11, a first battery 12, a first motion system 13 and a load 14, a second power supply system comprising a second DCDC converter (hereinafter referred to as a “second DDC”) 21, a second battery 22 and a second motion system 23, a power supply unit 30 and a power supply control device 40.

[0019] In this power supply system 1, a redundant power supply configuration is assumed, comprising the first power supply system and the second power supply system. The first power supply system and the second power supply system are connected via a first relay device 51 to supply a backup current. The second battery 22 is connected to the second power supply system via a second relay device 52 for battery protection. The connection / disconnection of the first relay device 51 and the second relay device 52 is controlled by the power supply control device 40.

[0020] The power supply unit 30 can supply energy to the first DDC 11 and the second DDC 21 in parallel. For this power supply unit 30, a high-voltage battery, configured to be rechargeable and dischargeable, such as a lithium-ion battery, can be used, for example.

[0021] The first DDC 11 converts the energy supplied by the power supply unit 30 and outputs the resulting energy to the first battery 12, the first motion system 13, and the load 14. Specifically, the first DDC 11 transforms high-voltage energy supplied by the power supply unit 30 into low-voltage energy and outputs the low-voltage energy to the first battery 12, the first motion system 13, and the load 14.

[0022] The first battery 12, for example, is an energy storage element, designed to be rechargeable and dischargeable, like a lead-acid battery. The first battery 12 can store the energy output (charge) by the first DDC 11 and output (discharge) the energy stored in the first battery 12 to the first motion system 13 and the load 14.

[0023] The first motion system 13 comprises an in-vehicle device associated with a movement (driving, turning, and stopping) of the vehicle. The first motion system 13 includes, for example, devices for steering, braking, assisting autonomous driving, and the like.

[0024] Load 14 comprises one or more in-vehicle devices that are not connected to the vehicle's movement. Load 14 includes, for example, a device such as a headlight or a windshield wiper.

[0025] The second DDC 21 can convert the energy supplied by the power supply unit 30 and output the resulting energy to the second battery 22 and the second motion system 23. Specifically, the second DDC 21 transforms high-voltage energy supplied by the power supply unit 30 into low-voltage energy and outputs the low-voltage energy to the second battery 22 and the second motion system 23.

[0026] The second battery 22 is an energy storage element designed to be rechargeable and dischargeable, such as a lithium-ion battery. In the first embodiment, the second battery 22 is a lithium iron phosphate battery (an LFP (lithium iron phosphate) battery) with a flat region in the SOC-OCV characteristic curve, as shown in Fig. Figure 2 illustrates this. The second battery 22 can store (charge) energy output by the second DDC 21 via the second relay device 52 and can output (discharge) the energy stored in the second battery 22 to the second motion system 23. The second battery 22 serves as a backup power supply to maintain the functions associated with vehicle movement if the first battery 12 fails while the vehicle is in motion.

[0027] The second motion system 23 is a motion system in which the same system as in the first motion system 13 is redundantly provided and includes a vehicle-internal device associated with a movement of the vehicle, similar to the first motion system 13.

[0028] The power supply control device 40 can manage the states, operations, and the like of the first DDC 11, the second DDC 21, the first battery 12, the second battery 22, the first relay device 51, and the second relay device 52 in order to control the state of the power supply system 1. According to the first embodiment, the power supply control device 40 performs control to estimate the full charge capacity of the second battery 22 with high accuracy.

[0029] The power supply control device 40 comprises a determination unit 41, a power transmission unit 42 and a capacity estimation unit 43.

[0030] The determination unit 41 determines whether a correction of the currently estimated full charge capacity is necessary if the state of charge (SOC) of the second battery 22 is equal to or greater than the first predetermined value. The determination unit 41 can be implemented, for example, by a monitoring electronic control unit (ECU) (not shown) capable of monitoring the voltage, current, and temperature of the second battery 22 using a sensor or the like.

[0031] If the determination unit 41 determines that there is a need to correct the full charge capacity of the second battery 22, the energy transfer unit 42 transfers a predetermined amount of energy from the second battery 22 to another battery (in the first embodiment, the first battery 12) where it is not necessary to correct the full charge capacity. The energy transfer unit 42 can, for example, be implemented by a power supply ECU (not shown) capable of controlling the connection state of the first relay device 51 and controlling an output voltage of the first DDC 11 or the second DDC 21, or by a monitoring ECU (not shown) capable of controlling the connection state of the second relay device 52.

[0032] The capacity estimation unit 43 performs a predetermined full-charge capacity estimation process on the second battery 22 according to a vehicle power supply state. The capacity estimation unit 43 can, for example, be implemented by a power supply ECU (not shown) capable of controlling the output voltage of the second DDC 21.

[0033] The detailed control of the determination unit 41, the energy transmission unit 42 and the capacity estimation unit 43 is described below. steering

[0034] Next, the control, which is carried out by the power supply control device 40, is described according to the first embodiment of the present invention with reference to Fig. 3 and Fig. 4A to 4C described. Fig. Figure 3 shows a flowchart illustrating a process relating to the estimation of a full charge capacity of the second battery 22, which is carried out by the power supply control device 40 according to the first embodiment. Fig. 4A to 4C show graphs illustrating an example of an ideal battery capacity degradation curve.

[0035] The in Fig. The process shown in point 3 is started when the vehicle's power supply is switched OFF (for example, IG_OFF), such as when the vehicle is parked.

[0036] (Step S301) The determination unit 41 determines whether the SOC of the second battery 22 is equal to or greater than a first predetermined value. This determination is performed to ascertain whether there is a need to intentionally reduce the SOC of the second battery 22 to ensure ΔSOC, which increases the estimation accuracy when the full-charge capacity estimation process is performed. Therefore, the first predetermined value is set to an SOC that ensures the ΔSOC necessary for estimating the full-charge capacity with high accuracy. In the lithium iron phosphate battery with the in Fig. In the illustrated SOC-OCV characteristic curve 2, it is possible to set a SOC lower than the flat area than the first predetermined value.

[0037] If the SOC of the second battery 22 is equal to or greater than the first predetermined value (Yes in S301), the process proceeds to step S302, and if the SOC of the second battery 22 is less than the first predetermined value (No in S301), the process proceeds to step S308.

[0038] (Step S302) The determination unit 41 determines whether a predetermined number of days or more have elapsed since the day on which a current full charge capacity for the second battery 22 was estimated (a last estimate processing date). This determination is performed to ascertain whether there is a need to correct (verify) the current full charge capacity due to deterioration of the second battery 22 over time. A suitable value for the predetermined number of days can optionally be determined based on the vehicle's usage environment or the like, but the predetermined number of days can, for example, be set to 30 days.

[0039] If a predetermined number of days or more have passed since the day on which the current full load capacity was estimated (Yes in S302), the process proceeds to step S303, and if the predetermined number of days or more have not passed since the day on which the current full load capacity was estimated (No in S302), this process ends.

[0040] (Step S303) The determination unit 41 estimates the deterioration state of the full charge capacity of the second battery 22 and determines whether there is a need to correct the current full charge capacity based on the estimated deterioration state. More precisely, the determination unit 41 determines whether a deviation between the current full charge capacity, estimated in the preceding process, and an ideal full charge capacity is equal to or greater than the second predetermined value. The ideal full charge capacity is a full charge capacity calculated from an aging deterioration curve (an ideal curve) of the battery capacity, which shows a change in the battery's capacity maintenance rate (= full charge capacity after deterioration / full charge capacity of a new product) with the number of years elapsed and the current usage condition of the vehicle.

[0041] The ideal curve can be obtained in advance by changing a battery temperature and a state of charge (SOC) level, which correlate with the degradation of battery capacity. For example, this illustrates... Fig. 4A ideal curves when batteries with the same SOC are left in an environment with a temperature of 25°C and when the batteries are left in an environment with a temperature of 40°C. Fig. Figure 4B illustrates ideal curves when batteries are left in a state of SOC 90% and when batteries are left in a state of SOC 80% under the same temperature environment.

[0042] The vehicle's state of use is, for example, the temperature environment in which the battery is actually exposed or the state of charge (SOC) at which the battery is used. The vehicle stores a history of the temperature environment or the battery's SOC, which changes from moment to moment, for example, using measured values ​​from various sensors mounted in the vehicle. An ideal full charge capacity can be calculated based on a usage ratio of the temperature environment or the SOC. For example, if a period of exposure to an environment at 25°C and a period of exposure to an environment at 40°C have essentially the same ratio (1:1) over four years, it is possible to calculate an average (four years) of two ideal curves, illustrated in [reference to diagram]. Fig. 4A, to be calculated as an ideal full charge capacity.

[0043] The determination unit 41 determines whether the ideal full load capacity, calculated using the scheme described above, and the actual full load capacity, estimated in the previous process, differ by the second predetermined value or more. The second predetermined value may be set to be a suitable value, for example, based on a specification or implementation required for the vehicle. This difference may be determined solely by a simple difference between the actual full load capacity and the ideal full load capacity calculated this time, or it may be determined by a transition of the actual full load capacity at any time point, estimated up to the previous time point, and a transition of the ideal full load capacity calculated up to that point. Fig. 4C). Furthermore, a full charge capacity can be set as the current full charge capacity, which is obtained by resetting a deviation difference that was achieved this time.

[0044] If the deviation between the current full charge capacity and the ideal full charge capacity is equal to or greater than the second predetermined value (Yes in S303), the process proceeds to step S304, and if the deviation between the current full charge capacity and the ideal full charge capacity is not equal to or greater than the second predetermined value (No in S303), this process ends.

[0045] (Step S304) The determination unit 41 determines whether the open-circuit voltage (OCV) of the second battery 22 is higher than the open-circuit voltage (OCV) of the first battery 12 by a third predetermined value or more. This determination is performed so that the process for reducing the state of charge (SOC) of the second battery 22, which is required to ensure ΔSOC, can be carried out without unnecessarily discharging the energy of the second battery 22. In particular, since this process is assumed to be carried out in a state where the vehicle power supply is switched OFF, such as when parked, the process also serves to restore the SOC of the first battery 12, which has been discharged due to prolonged parking.

[0046] The third predetermined value is set based on whether energy transfer from the second battery 22 to the first battery 12 can be carried out efficiently, as described below. For example, if there is essentially no voltage difference between the open-circuit voltage of the second battery 22 and the open-circuit voltage of the first battery 12, essentially no current flows between the batteries. Accordingly, the transferred energy is also reduced, and the state of charge (SOC) of the second battery 22 cannot be efficiently reduced. Therefore, the third predetermined value is set to allow for a specific voltage difference. It is desirable for this predetermined value to be set taking into account the voltage drop due to the resistance of a cable run (cable harness or the like) from the second battery 22 to the first battery 12.

[0047] If the open-circuit voltage of the second battery 22 is higher than the open-circuit voltage of the first battery 12 by the third predetermined value or more (Yes in S304), the process proceeds to step S305. If the open-circuit voltage of the second battery 22 is not higher than the open-circuit voltage of the first battery 12 by the third predetermined value or more (No in S304), the process proceeds to step S301.

[0048] (Step S305) The power transfer unit 42 starts the power transfer from the second battery 22 to the first battery 12. The power transfer unit 42 can start the power transfer by switching ON the second relay device 52, which connects the second battery 22 to the second power supply system, or by switching ON the first relay device 51, which connects the first power supply system to the second power supply system.

[0049] (Step S306) The determination unit 41 determines whether the SOC of the second battery 22 has become equal to or less than a fourth predetermined value. This determination is performed to ascertain whether the process of reducing the SOC of the second battery 22, necessary to ensure ΔSOC, is complete. Therefore, the fourth predetermined value is set to an SOC that is less than the first predetermined value, and with which the ΔSOC necessary for estimating the full charge capacity with high accuracy is ensured. In the lithium iron phosphate battery with the in Fig. In the SOC-OCV characteristic curve shown in section 2, it is possible to set the SOC (for example, 30%) lower than the flat area as the fourth predetermined value.

[0050] The determination unit 41 determines whether a discharge current of the second battery 22 is equal to or less than a fifth predetermined value, instead of determining whether the state of charge (SOC) of the second battery 22 has become equal to or less than the fourth predetermined value. This is because, by considering the discharge current of the second battery 22, the determination unit 41 can determine that energy transfer has taken place if there is no voltage difference between the open-circuit voltage of the second battery 22 and the open-circuit voltage of the first battery 12, and can indirectly determine that the SOC of the second battery 22 has been reduced to the SOC necessary to ensure ΔSOC.

[0051] If the SOC of the second battery 22 is equal to or lower than the fourth predetermined value (or the discharge current is equal to or less than the fifth predetermined value) (Yes in S306), the process proceeds to step S307, and if the SOC of the second battery 22 is not equal to or less than the fourth predetermined value (or the discharge current is not equal to or less than the fifth predetermined value) (No in S306), the process is repeated from step S306.

[0052] (Step S307) The power transfer unit 42 terminates the power transfer from the second battery 22 to the first battery 12. The power transfer unit 42 can terminate the power transfer by switching OFF the second relay device 52, which connects the second battery 22 to the second power supply system, or by switching OFF the first relay device 51, which connects the first power supply system to the second power supply system.

[0053] (Step S308) The next time the vehicle's power supply is switched ON (READY_ON or similar), the determination unit 41 sets a marker to request the execution of a process to estimate a predetermined full charge capacity to an ON state. The capacity estimator 43 acknowledges this marker when the vehicle's power supply is switched ON, and when the marker is set to the ON state, the capacity estimator 43 executes a process to estimate the full charge capacity of the second battery 22 using the assured ΔSOC with high accuracy. When the capacity estimator 43 completes the process to estimate the full charge capacity of the second battery 22, the determination unit 41 sets the marker to the OFF state.The full charge capacity estimation process can be performed using a known current integration method in a charging process from a low SOC to a high SOC.

[0054] If the vehicle's power supply is switched ON during the processes from steps S301 to S308 as described above, the indicator to request execution of the full charge capacity estimation process is OFF. Accordingly, the full charge capacity estimation process is not performed. The next time the vehicle's power supply is switched OFF, the process from step S301 is restarted as described above. Second example configuration

[0055] Fig. Figure 5 shows a diagram illustrating a schematic configuration example of a power supply system 2 for a vehicle, comprising a power supply device 40 according to a second embodiment of the present invention. The Fig. The power supply system 2 shown in Figure 5 comprises a first power supply system comprising a first DDC 11, a first battery 12, a first motion system 13 and a load 14, a second power supply system comprising a second DDC 21, a second battery 22 and a second motion system 23, a power supply unit 30 and a power supply control device 40.

[0056] In this power supply system 2, a redundant power supply configuration is assumed, employing a first power supply system and a second power supply system. The first power supply system and the second power supply system are interconnected via the first relay device 51 to supply a dark current. Additionally, the first power supply system and the second power supply system are interconnected via a third relay device 53 and a switching DC-DC converter (hereinafter referred to as a "switching DDC") 60. The second battery 22 is connected to the switching DDC 60 for battery protection via the second relay device 52 and to the second motion system 23 of the second power supply system via the fourth relay device 54.The connection / disconnection of the first relay device 51, the second relay device 52, the third relay device 53, the fourth relay device 54 and the switching DDC 60 are controlled by the power supply control device 40.

[0057] In the configuration of the power supply system 2 of the second embodiment, the power supply unit 30, the first DDC 11, the first motion system 13, the load 14 and the second motion system 23 are the same as in the power supply system 1 of the first embodiment and therefore a description thereof is neglected.

[0058] The first battery 12, for example, is an energy storage element, designed to be rechargeable and dischargeable, like a lead-acid battery. The first battery 12 can store (charge) energy output by the first DDC 11 and energy output by the second DDC 21, and discharge (provide) the energy stored in the first battery 12 to the first motion system 13 and the load 14.

[0059] The second DDC 21 converts the energy supplied by the power supply unit 30 and outputs the resulting energy to the first battery 12, the first motion system 13, and the load 14. Specifically, the second DDC 21 transforms high-voltage energy supplied by the power supply unit 30 into low-voltage energy and outputs the low-voltage energy to the first battery 12, the first motion system 13, and the load 14.

[0060] The second battery 22 is an energy storage element designed to be rechargeable and dischargeable, for example, a lithium-ion battery. In the second embodiment, the second battery 22 is a lithium iron phosphate battery (an LFP battery) with a flat region in the SOC-OCV characteristic curve, as shown in Fig. Figure 2 illustrates this. The second battery 22 can output (discharge) the energy stored in the second battery 22 to the second motion system 23 via the second relay device 52 and the fourth relay device 54. The second battery 22 serves as a backup power supply to maintain functions related to the movement of the vehicle if the first battery 12 fails while the vehicle is in motion.

[0061] The power supply control device 40 can manage states, operations, or the like of the first DDC 11, the second DDC 21, the first battery 12, the second battery 22, the first relay device 51, the second relay device 52, the third relay device 53, the fourth relay device 54, and the switching DDC 60 in order to control the state of the power supply system 2. The power supply control device 40 according to the second embodiment performs control for estimating the full charge capacity of the second battery 22 with high accuracy.

[0062] The power supply control device 40 comprises a determination unit 41, a power transmission unit 42 and a capacity estimation unit 43.

[0063] Determination unit 41 determines whether it is necessary to estimate the currently estimated full charge capacity if the state of charge (SOC) of the second battery 22 is equal to or greater than the first predetermined value. Determination unit 41 can be implemented, for example, by a monitoring ECU (not illustrated) capable of monitoring the voltage, current, and temperature of the second battery 22 using a sensor or the like.

[0064] If the determination unit 41 determines that there is a need to correct the full charge capacity of the second battery 22, the energy transfer unit 42 transfers a predetermined amount of energy from the second battery 22 to another battery (in the second embodiment, the first battery 12) for which it is not necessary to correct the full charge capacity. Additionally, the energy transfer unit 42 can also perform charging by reading an energy return from the first battery 12 to the second battery 22 during this energy transfer.The power transmission unit 42 can be implemented, for example, by a power supply ECU (not shown), capable of controlling a connection state of the first relay device 51, the third relay device 53, the fourth relay device 54 and the switching DCDC converter 60, or by a monitoring ECU (not shown), capable of controlling a connection state of the second relay device 52.

[0065] The capacity estimation unit 43 performs a predetermined full-charge capacity estimation process on the second battery 22 according to a vehicle's energy supply state. The capacity estimation unit 43 can, for example, be implemented by an energy supply ECU (not shown) capable of controlling the output voltage of the switching DDC 60.

[0066] The detailed control of the determination unit 41, the energy transmission unit 42 and the capacity estimation unit 43 is described below. steering

[0067] Next, the control system implemented by the power supply control device 40 according to the second embodiment of the present invention will be described with reference to Fig. 6A and Fig. 6B described. Fig. 6A and Fig. Figure 6B are flowcharts illustrating a process relating to estimating the full charge capacity of the second battery 22, as performed by the power supply control device 40 according to the second embodiment. Before the steps described in Fig. 6A and Fig. The step illustrated in the second embodiment, 6B, is the one that performs the same process as the step described in Fig. 3 in the first embodiment is designated with the same reference numeral and a description thereof is neglected.

[0068] (Step S605) If, in step S304, it is determined that the open-circuit voltage of the second battery 22 is higher than the open-circuit voltage of the first battery 12 by the third predetermined value or more, the power transfer unit 42 initiates power transfer from the second battery 22 to the first battery 12. The power transfer unit 42 can initiate the power transfer by switching ON the second relay device 52, which connects the second battery 22 to the second power supply system, or by switching ON the third relay device 53 and the switching DDC 60, which connect the first power supply system to the second power supply system. Simultaneously, the capacity estimation unit 43 initiates a process to estimate the full-charge capacity of the second battery 22 based on the amount of current discharged from the second battery 22 to the first battery 12, which is controlled by the switching DDC 60.Since the open-circuit voltage or the transmission current can be accurately controlled by the switching DDC 60, it is possible to perform highly accurate estimations of the full charge capacity of the second battery 22 by applying a known current integration method during a discharge process from the high SOC to the low SOC.

[0069] (Step S607) If a determination is made in step S306 that the state of charge (SOC) of the second battery 22 is equal to or less than the fourth predetermined value (or the discharge current is equal to or less than the fifth predetermined value), the power transfer unit 42 terminates the power transfer from the second battery 22 to the first battery 12. The power transfer unit 42 can terminate the power transfer by switching OFF the second relay device 52, which connects the second battery 22 to the second power supply system, or by switching OFF the third relay device 53 and the switching DDC 60, which connect the first power supply system to the second power supply system. Furthermore, the capacity estimation unit 43 terminates the process of estimating the full-charge capacity of the second battery 22.

[0070] (Step S608) The capacity estimation unit 43 determines whether the estimation of the full charge capacity of the second battery 22 has been completed due to the energy transfer. If the full charge capacity estimation is complete (Yes in S608), the process proceeds to step S609. If the full charge capacity estimation is not complete (No in S608), the process proceeds to step S611.

[0071] (Step S609) The energy transfer unit 42 initiates a charging process of the second battery 22 using energy from the first battery 12. This charging is performed to increase the state of charge (SOC) of the second battery 22, which is reduced due to the energy transfer. The charge amount can be the total amount of energy transferred or a portion thereof. The energy transfer unit 42 can initiate the charging process by switching ON the second relay device 52, which connects the second battery 22 to the second power supply system, or by switching ON the third relay device 53 and the switching DDC 60, which connect the first power supply system to the second power supply system.

[0072] (Step S610) The determination unit 41 determines whether the state of charge (SOC) of the second battery 22 has become equal to or greater than a sixth predetermined value. This determination is performed to ascertain whether sufficient energy has returned to the second battery 22. Here, the third predetermined value, which represents a sufficient amount of energy, can be set, for example, to the amount of energy (state of charge) necessary to ensure the functions associated with the movement of the vehicle.

[0073] If the state of charge (SOC) of the second battery 22 becomes equal to or greater than the sixth predetermined value (Yes in S610), this process ends. If the SOC of the second battery 22 is not equal to or greater than the sixth predetermined value (No in S610), the process from step S610 is executed repeatedly.

[0074] (Step S611) The next time the vehicle's power supply is switched ON (READY_ON or similar), the determination unit 41 sets a marker to an ON state to request the execution of a process to estimate a predetermined full charge capacity. The capacity estimator 43 acknowledges this marker when the vehicle's power supply is switched ON, and when the marker is set to the ON state, the capacity estimator 43 executes a process to estimate the full charge capacity of the second battery 22 using the assured ΔSOC with high accuracy. When the capacity estimator 43 completes the process to estimate the full charge capacity of the second battery 22, the determination unit 41 sets the marker to the OFF state.The full charge capacity estimation process can be performed using a known current integration method in a charging process from a low SOC to a high SOC.

[0075] If the vehicle's power supply is switched ON during the process from steps S301 to S611 as described above, the indicator to request execution of the full charge capacity estimation process is OFF. Accordingly, the full charge capacity estimation process is not performed. The next time the vehicle's power supply is switched OFF, the process is restarted from step S301 as described above. Third example configuration

[0076] A power supply control device 40 according to a third embodiment has the same configuration as the power supply control device applied to the in Fig. 1 Energy supply system 1 of the first embodiment shown. steering

[0077] A control system implemented by the power supply control device 40 according to the third embodiment of the present invention is referred to as Fig. 7 described. Fig. Figure 7 shows a flowchart illustrating a process related to estimating the full charge capacity of the second battery 22, which is performed by the power supply control device 40 according to the third embodiment. In the Fig. The flowchart shown in section 7 is a determination in step S701 to the one in Fig. 3. Added to the flowchart of the first embodiment shown. Since the steps that begin with step S701 in Fig. 7 are different, the same as in the process that relates to Fig. Since it is described in section 3, a description of it is neglected.

[0078] (Step S701) The determining unit 41 estimates a deterioration state of the full charge capacity of the second battery 22 based on a temperature of the second battery 22, and estimates whether there is a need to correct the current full charge capacity based on the estimated deterioration state. More precisely, the control unit 41 determines whether the ratio of a time period in which the temperature of the second battery 22 is equal to or lower than a predetermined temperature to a time period from the start of use of the second battery 22, which is obtained from predetermined battery temperature information, is equal to or less than a sixth predetermined value.

[0079] A battery designed as a lithium-ion battery, a lead-acid battery, or the like, has the characteristic that battery degradation progresses more rapidly at high temperatures than at low temperatures. For example, this illustrates... Fig. 8 Aging deterioration characteristics when batteries with the same state of charge (SOC) are left for a long period of time in an environment with temperatures of 0°C, 10°C, 25°C, 45°C, 60°C and 70°C. As in Fig. Figure 8 illustrates that the capacity retention rate of batteries with the same state of charge deteriorates to 93% after 240 days if the battery is left uncharged for an extended period in a state where the ambient battery temperature is set to 0°C (O-plots). The capacity retention rate deteriorates to 62% after 120 days if the battery is left uncharged for an extended period in a state where the ambient battery temperature is set to 70°C (X-plots). Therefore, proper management of the ambient temperature is significant for battery performance.

[0080] When the determination is performed in step S701, the determination unit 41 calculates a "presence time" by accumulating the time the batteries are in the states, for each preset temperature range (B temperature: Tb1 to Tb1). n ), as in Fig. Figure 9 shows the battery temperature information. The presence time can be solely the time the vehicle is in use, such as driving, or it can include time when the vehicle is not in use, such as parking. The temperature range can be optionally set, such as in 1°C or 10°C units. For example, the presence time during which the second battery 22 was used at temperature Tb3 from the start of vehicle use until the present time t3, as shown in Figure 9, is the time the second battery 22 was in use at temperature Tb3. Fig. 9 illustrates.

[0081] Next, the unit of determination 41 divides the presence time in each temperature range, as shown in Fig. 9, by an elapsed time from the start of the vehicle's use until the present, to determine a presence frequency (= presence time / elapsed time) for each temperature division (B temperature: Tb1 to Tb n ) to calculate, as in Fig. Figure 10 illustrates the battery temperature information. The elapsed time can be calculated using the number of days calculated in step S302. The presence time and presence frequency described above can be calculated each time step S701 is executed, or they can be calculated and stored sequentially during vehicle use. For example, the presence frequency at which the second battery 22 was used at temperature Tb3 from the start of vehicle use to the present is p3 (= t3 / elapsed time), as shown in Figure 10. Fig. Figure 10 shows a distribution map of the presence frequencies (temperature frequencies) in the respective temperature range, obtained in this way. Fig. 11 shown.

[0082] The determination unit 41 determines whether the ratio of the time during which the temperature of the second battery 22 is equal to or less than the predetermined temperature, to the time since the start of use of the second battery 22, is equal to or less than the sixth predetermined value, based on an obtained temperature frequency distribution. This determination is performed to ascertain whether a period during which the second battery 22 is used at a low temperature is long or short. If the second battery 22 is used at a low temperature for a long period, it can be estimated that the battery degradation rate is slow, and if the second battery 22 is not used at a low temperature for a long period, it can be estimated that the battery degradation rate is fast. Therefore, if, for example, an area of ​​a shaded section, shown in Fig. If the value is smaller than 11, it can be determined that the battery is likely to deteriorate. The sixth predetermined value can optionally be set according to the capacity, characteristics, and the like of the second battery 22.

[0083] If the ratio of the time period in which the temperature of the second battery 22 becomes equal to or less than the predetermined temperature to the time period since the start of use of the second battery 22 is equal to or less than the sixth predetermined value (Yes in step S701), the process proceeds to step S304, and if the ratio of the time period in which the temperature of the second battery 22 becomes equal to or less than the predetermined temperature to the time period since the start of use of the second battery 22 is not equal to or less than the sixth predetermined value (No in S701), the process ends. Fourth example configuration

[0084] A power supply control device 40 according to a fourth embodiment has the same configuration as the power supply control device applied to the in Fig. 5 Energy supply system 2 of the second embodiment shown. steering

[0085] Fig. Figure 12 shows a flowchart illustrating part of a process relating to estimating the full charge capacity of the second battery 22, which is carried out by the power supply control device 40 according to the fourth embodiment of the present invention. The Fig. The illustrated flowchart 12 is further enhanced by adding the determination in step S701, described in the third embodiment, to which in Fig. The flowchart of the second embodiment shown in Figure 6A is obtained. In step S701, the determining unit 41 estimates a deterioration state of the full charge capacity of the second battery 22 based on a temperature of the second battery 22 and determines whether there is a need to correct the full charge capacity based on the estimated deterioration state. More precisely, the determining unit 41 determines whether the ratio of the time during which the temperature of the second battery 22 is equal to or lower than a predetermined temperature to the time since the second battery 22 was first used is equal to or less than the sixth predetermined value.

[0086] The steps that begin with step S701 in Fig. The 12 different ones are the same as the processes that are in Fig. 6A are described. Furthermore, connections A, B and C of Fig. 12 to the connections A, B and C of the in Fig. coupled to the flowchart of the second embodiment shown in 6B. Modification example

[0087] In the third and fourth embodiments, step S701 is added to steps S302 and S303 to determine whether there is a need to correct the currently estimated full-charge capacity. Additionally, steps S302 and S701 alone can determine whether there is a need to correct the currently estimated full-charge capacity. Operation and effects

[0088] According to the energy supply control device 40 of the embodiment of the present invention described above, the energy of the target battery (the second battery 22), in which there is no need to correct the full charge capacity because the state of charge is equal to or greater than a predetermined value (the first predetermined value), is transferred to another battery (the first battery 12) and reduced to a predetermined low state of charge (SOC) at a time when the vehicle's power supply is switched OFF. Charging is carried out with a wide SOC range from low SOC to high SOC at a time when the vehicle's power supply is next switched ON, and the full charge capacity of the target battery is calculated based on the current integration method.Accordingly, it is possible to implement a process for estimating the battery's full charge capacity at a suitable time. In particular, it is possible to suppress the influence of measurement errors in current, voltage, or the like in the sensor by ensuring a large ΔSOC and to estimate the target battery's full charge capacity with high accuracy.

[0089] Furthermore, in the energy supply control device 40 according to the exemplary embodiment, a determination is made as to whether there is a need to correct the full charge capacity, based on whether a predetermined number of days have passed since the day on which the battery's full charge capacity was last estimated, or based on a deterioration state of the battery's full charge capacity. The deterioration state is estimated based on whether a deviation between a full charge capacity obtained from a predetermined aging deterioration curve and a full charge capacity estimated by the capacity estimator is equal to or greater than a predetermined value (the second predetermined value). By taking the deviation of the full charge capacity into account in this way, it is possible to accurately determine the need for a full charge capacity correction.Furthermore, the state of deterioration is estimated based on whether the ratio of the time the battery temperature remains equal to or below a predetermined temperature to the time since the battery was first used is equal to or below a predetermined value (the sixth predetermined value). It is possible to more accurately determine the need for full-charge capacity correction by considering the battery temperature in this way. These provisions make it possible to reduce the energy consumption required for the full-charge capacity estimation process and to shorten the autonomous driving lockout period following a decrease in the battery's state of charge during the full-charge capacity estimation process in a vehicle with autonomous driving capabilities.

[0090] Furthermore, if, in the energy supply control device 40 according to the exemplary embodiment, the open-circuit voltage of the target battery is higher than the open-circuit voltage of a non-target battery by a predetermined value (the third predetermined value) or more, a predetermined amount of energy is transferred from the target battery to another battery. Accordingly, it is possible to avoid inefficient energy transfer. Furthermore, if the state of charge of the target battery becomes equal to or less than a predetermined value (the fourth predetermined value), or if the current discharged from the target battery becomes equal to or less than a predetermined value (the fifth predetermined value), the energy transfer ends. Accordingly, it is possible to avoid wasteful energy transfer.Since the full charge capacity estimation process is performed without carrying out energy transfer for the battery whose state of charge is less than the predetermined value (the first predetermined value), work can be saved in energy transfer.

[0091] Furthermore, in the energy supply control device 40 according to the exemplary embodiment, it is also possible to estimate the full charge capacity of the second battery 22 with high accuracy by applying a known current integration method to a discharge process from a high SOC to a low SOC, which occurs when energy is transferred from the second battery 22 to the first battery 12, as long as the first battery 12 and the second battery 22 are connected by the switching DDC 60, which is capable of controlling a current with high accuracy.

[0092] Although the embodiment of the present invention has been described above, the present invention can encompass a power supply control device, a method for estimating the full charge capacity performed by the power supply control device, a program for estimating the full charge capacity, a permanently computer-readable recording medium that stores the program, or a vehicle with the power supply control device attached therein.

[0093] The energy supply control device of the present invention can, for example, be used for a vehicle in which an energy supply system is mounted, comprising two energy supply systems.

Claims

[1] Energy supply control device (40) that estimates a full charge capacity of a battery (12; 22) that is mounted in a vehicle, the energy supply control device comprising: a determination unit (41) designed to determine whether there is a need to correct a currently estimated full charge capacity when a state of charge of the battery (12; 22) is equal to or greater than a first predetermined value at a time when the power supply from the vehicle is switched OFF, wherein the determination unit (41) is set up, to estimate a deterioration state of the full charge capacity of the battery (12; 22), and is set up to determine whether there is a need to correct the full charge capacity based on the estimated deterioration state, and to estimate the deterioration state based on whether the ratio of a time period in which a battery temperature (12; 22) becomes equal to or lower than a predetermined temperature to a time period from the start of use obtained from predetermined battery temperature information is equal to or less than a sixth predetermined value; an energy transfer unit (42) configured to transfer a predetermined amount of energy from battery (12; 22) to another battery (12; 22) when the determining unit (41) determines that there is a need to correct the currently estimated full charge capacity; and a capacity estimation unit (43) configured to perform a predetermined full charge capacity estimation process at the battery (12; 22) at a time when the vehicle's power supply is switched ON after the energy transfer by the energy transfer unit (42) or during the energy transfer by the energy transfer unit (42). [2] Energy supply control device (40) according to claim 1, wherein the determination unit (41) is configured to determine whether there is a need to correct the full charge capacity based on whether a predetermined number of days have passed from a day on which the full charge capacity of the battery (12; 22) was last estimated by the capacity estimation unit (43). [3] Energy supply control device (40) according to claim 1 or 2, wherein the determination unit (41) is configured to estimate the deterioration state based on whether a deviation between a full charge capacity obtained from a predetermined aging deterioration curve and the full charge capacity estimated by the capacity estimation unit (43) is equal to or greater than a second predetermined value. [4] Energy supply control device (40) according to any one of claims 1 to 3, wherein the energy transfer unit (42) is configured to transfer the predetermined energy from battery (12; 22) to the other battery (12; 22) when an open-circuit voltage of battery (12; 22) is higher by a third predetermined value or more than an open-circuit voltage of the other battery (12; 22). [5] Energy supply control device (40) according to any one of claims 1 to 4, wherein the energy transfer unit (42) is configured to terminate the energy transfer when the charge level of the battery (12; 22) becomes equal to or less than a fourth predetermined value less than the first predetermined value, or when a current value discharged from the battery (12; 22) becomes equal to or less than a fifth predetermined value. [6] Energy supply control device (40) according to claim 1, wherein the capacity estimation unit (43) is configured to perform the full charge capacity estimation process at a time when the vehicle's energy supply is switched ON, without the determination unit (41) performing the determination if the state of charge of the battery (12; 22) is less than the first predetermined value. [7] Energy supply control device (40) according to any one of claims 1 to 5, wherein the energy transfer unit (42) is configured to carry out a charging process of the battery (12; 22) at least with part of the energy transferred to the other battery (12; 22) when the estimation of the full charge capacity of the battery (12; 22) due to the energy transfer is completed.

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