JP2020024182A - Power source control device - Google Patents

Abstract

To provide a power source control device that is able to perform an estimation process for a fully charged capacity for a battery at appropriate timing and by means of appropriate means.SOLUTION: A power source control device that estimates a fully charged capacity for a battery mounted in a vehicle, comprises; a determination unit that determines whether fully charged capacity currently estimated needs to be corrected if an amount of power stored in the battery is equal to or larger than a predetermined amount, at off-timing of a power source of the vehicle; a power transfer unit that, if the determination unit determines that the fully charged capacity needs to be corrected, transfers predetermined power from the battery to another battery; and a capacity estimation unit that performs a predetermined fully charged capacity estimation process for the battery during power transfer by the power transfer unit or at on-timing of the power source of the vehicle after the power transfer by the power transfer unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply control device for estimating a full charge capacity of a battery mounted on a vehicle.

  Patent Literature 1 discloses a technique for accurately estimating a full charge capacity of a battery. In this technology, every time a vehicle is charged from an external power supply, the full charge capacity of the battery is calculated by the current integration method, and the previously calculated full charge capacity is added to the currently calculated full charge capacity at a predetermined ratio. Is learned as a new full charge capacity. As a result, the influence of sensor errors and detection errors can be reduced, and the full charge capacity of the battery can be accurately estimated.

JP 2013-101072 A

  In a battery such as a lithium iron phosphate battery having a flat SOC-OCV characteristic (see FIG. 2), it is difficult to determine the amount of charge (SOC) from the open-circuit voltage (OCV). It is conceivable to calculate the SOC by using Here, since the full charge capacity required for calculating the SOC by the current integration method is a value that changes with the deterioration of the battery, it is desirable to increase the frequency of performing the estimation process and acquire the latest value as possible. .

  However, in the method described in Patent Document 1, the process of estimating the full charge capacity is performed only at a limited opportunity such as the timing of performing external charging. Further, in order to accurately estimate the full charge capacity, it is necessary to secure a large SOC difference (ΔSOC) before and after charging. However, in the method described in Patent Document 1, since external charging is performed as a consequence, ΔSOC is secured. Is not enough. Therefore, there is room for improvement in the timing and method for performing the estimation process of the full charge capacity.

  The present invention has been made in view of the above problems, and has as its object to provide a power supply control device capable of performing a process of estimating a full charge capacity of a battery at a suitable timing and method.

  In order to solve the above-described problem, one embodiment of the present invention is a power supply control device for estimating a full charge capacity of a battery mounted on a vehicle, and the power storage amount of the battery is reduced at a timing when the vehicle is turned off. A determination unit for determining whether the currently estimated full charge capacity needs to be corrected when the full charge capacity is equal to or more than the first predetermined value; A power transfer unit for transferring predetermined power from the vehicle to another battery; and a predetermined full charge for the battery at a timing when the vehicle is powered on after the power transfer by the power transfer unit or during the power transfer by the power transfer unit. A capacity estimating unit that performs a charging capacity estimating process.

  According to the power supply control device of the present invention, the process of estimating the full charge capacity of the battery can be performed at a suitable timing and method.

FIG. 1 is a diagram illustrating a schematic configuration example of a power supply system including a power supply control device according to a first embodiment. The figure which shows an example of the SOC-OCV characteristic of a lithium ion battery 9 is a flowchart illustrating a procedure of a process related to estimating a full charge capacity of a battery performed by the power supply control device according to the first embodiment. Diagram showing an example of an ideal curve of battery capacity deterioration FIG. 3 is a diagram illustrating a schematic configuration example of a power supply system including a power supply control device according to a second embodiment. 9 is a flowchart illustrating a procedure of a process related to estimation of a full charge capacity of a battery performed by the power supply control device according to the second embodiment. 9 is a flowchart illustrating a procedure of a process related to estimating a full charge capacity of a battery performed by the power supply control devices according to the second and fourth embodiments. 11 is a flowchart illustrating a procedure of a process related to estimation of a full charge capacity of a battery performed by a power supply control device according to a third embodiment. Diagram showing an example of aging characteristics when the environmental temperature of the battery is changed The figure which shows the example which calculated the existence time for every battery temperature The figure which shows the example which calculated the presence frequency for every battery temperature FIG. 10 is a graph showing the frequency of presence of the battery in FIG. 10 for each temperature. 11 is a flowchart illustrating a procedure of a process related to estimating a full charge capacity of a battery performed by a power supply control device according to a fourth embodiment.

<Overview>
The power supply control device of the present invention transfers the power of the battery whose full charge capacity needs to be corrected to another battery at the timing when the power supply of the vehicle is turned off, and reduces the power to a predetermined SOC. Then, at the timing when the power of the vehicle is turned on, the full charge capacity of the battery to be corrected is calculated by a current integration method using a large SOC width. This makes it possible to estimate a highly accurate full charge capacity.

<First embodiment>
[Constitution]
FIG. 1 is a diagram illustrating a schematic configuration example of a vehicle power supply system 1 including a power supply control device 40 according to a first embodiment of the present invention. The power supply system 1 illustrated in FIG. 1 includes a first DCDC converter (hereinafter, referred to as “first DDC”) 11, a first battery 12, a first exercise system 13, and a first load including a load 14. A power supply system, a second DCDC converter (hereinafter referred to as “second DDC”) 21, a second power supply system including a second battery 22, and a second exercise system 23, and a power supply unit 30, A power control device 40.

  The power supply system 1 employs a redundant power supply configuration including a first power supply system and a second power supply system. The first power supply system and the second power supply system are connected via a first relay device 51 for supplying dark current. The second battery 22 is connected to a second power supply system via a second relay device 52 for protecting the battery. The connection and disconnection of the first relay device 51 and the second relay device 52 are controlled by the power supply control device 40.

  The power supply unit 30 can supply power to the first DDC 11 and the second DDC 21 in parallel. For the power supply unit 30, a high-voltage battery configured to be chargeable and dischargeable, such as a lithium ion battery, is used.

  The first DDC 11 can convert the power supplied from the power supply unit 30 and output the converted power to the first battery 12, the first exercise system 13, and the load 14. Specifically, the first DDC 11 reduces the high-voltage power supplied from the power supply unit 30 to low-voltage power, and outputs the low-voltage power to the first battery 12, the first exercise system 13, and the load 14. I do.

  The first battery 12 is a chargeable / dischargeable power storage element such as a lead battery. The first battery 12 can store (charge) the power output from the first DDC 11 and output (discharge) the power stored therein to the first exercise system 13 and the load 14. be able to.

  The first motion system 13 includes an in-vehicle device related to the motion (run, turn, stop) of the vehicle. The first exercise system 13 includes, for example, devices such as steering, braking, and automatic driving assistance.

  The load 14 includes one or more in-vehicle devices that are not involved in the movement of the vehicle. The load 14 includes, for example, devices such as a headlamp and a wiper.

  The second DDC 21 can convert the power supplied from the power supply unit 30 and output the converted power to the second battery 22 and the second exercise system 23. Specifically, the second DDC 21 reduces the high-voltage power supplied from the power supply unit 30 to low-voltage power, and outputs the low-voltage power to the second battery 22 and the second exercise system 23.

  The second battery 22 is a chargeable / dischargeable power storage element such as a lithium ion battery. In the first embodiment, the second battery 22 is an iron phosphate-based lithium ion battery (LFP battery) having a flat region in SOC-OCV characteristics as shown in FIG. The second battery 22 can store (charge) the power output from the second DDC 21 via the second relay device 52, and can store the stored power in the second exercise system. 23 (discharge). The second battery 22 has a role as a backup power supply for maintaining functions related to the motion of the vehicle when the first battery 12 fails during driving of the vehicle.

  The second motion system 23 is provided with the same system as the first motion system 13 in a redundant manner, and includes an in-vehicle device related to the motion of the vehicle, similarly to the first motion system 13. .

  The power control device 40 manages the state and operation 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. Thus, the state of the power supply system 1 can be controlled. The power supply control device 40 of the first embodiment executes control for estimating the full charge capacity of the second battery 22 with high accuracy.

  The power supply control device 40 includes a determination unit 41, a power transfer unit 42, and a capacity estimation unit 43.

  The determination unit 41 determines whether it is necessary to correct the currently estimated full charge capacity when the state of charge (SOC) of the second battery 22 is equal to or more than the first predetermined value. Do. The determination unit 41 can be realized by, for example, a monitoring ECU (not shown) that can monitor the voltage, current, and temperature of the second battery 22 using a sensor or the like.

  When the determination unit 41 determines that the full charge capacity of the second battery 22 needs to be corrected, the power transfer unit 42 uses another battery (the first battery) that does not need to be corrected from the second battery 22. In the embodiment, a predetermined power is transferred to the first battery 12). The power transfer unit 42 is, for example, a power supply ECU (not shown) that can control the connection state of the first relay device 51 and can control the output voltage of the first DDC 11 and the second DDC 21. ), Or a monitoring ECU (not shown) that can control the connection state of the second relay device 52.

  The capacity estimation unit 43 performs a predetermined full charge capacity estimation process on the second battery 22 according to the power supply state of the vehicle. The capacity estimation unit 43 can be realized by, for example, a power supply ECU (not shown) that can control the output voltage of the second DDC 21.

  Detailed control of the determination unit 41, the power transfer unit 42, and the capacity estimation unit 43 will be described later.

[control]
Next, control executed by the power supply control device 40 according to the first embodiment of the present invention will be described with further reference to FIGS. FIG. 3 is a flowchart illustrating a process related to the estimation of the full charge capacity of the second battery 22 performed by the power supply control device 40 according to the first embodiment. FIG. 4 is a diagram illustrating an example of an ideal curve of battery capacity deterioration.

  The process illustrated in FIG. 3 is started when the power of the vehicle is turned off (eg, IG_OFF), such as when the vehicle is parked.

(Step S301)
The determining 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 in order to determine whether it is necessary to intentionally lower the SOC of the second battery 22 in order to secure ΔSOC that increases the estimation accuracy when performing the full charge capacity estimation process. Will be Therefore, the first predetermined value is set to the SOC determined to be able to secure ΔSOC necessary for estimating the full charge capacity with high accuracy. In the iron-phosphate-based lithium-ion battery having the SOC-OCV characteristics illustrated in FIG. 2, the SOC lower than the flat region can be set as the first predetermined value.

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

(Step S302)
The determining unit 41 determines whether or not a predetermined number of days or more have elapsed since the date when the current full charge capacity of the second battery 22 was estimated (the last estimated processing date). This determination is performed to determine whether the current full charge capacity needs to be corrected (reviewed) due to the deterioration of the second battery 22 with time. The predetermined number of days can be arbitrarily set to an appropriate value based on the usage environment of the vehicle or the like, but may be 30 days as an example.

  When a predetermined number of days or more have elapsed since the day when the current full charge capacity was estimated (S302, Yes), the process proceeds to step S303, and the predetermined number of days or more have elapsed since the day when the current full charge capacity was estimated. If not (S302, No), this process ends.

(Step S303)
The determining unit 41 estimates the state of deterioration of the full charge capacity of the second battery 22, and determines whether the current full charge capacity needs to be corrected based on the estimated state of deterioration. More specifically, determination unit 41 determines whether or not the difference between the current full charge capacity estimated in the previous process and the ideal full charge capacity is equal to or greater than a second predetermined value. The ideal full charge capacity is a battery capacity aging curve (ideal curve) showing the change in the battery capacity retention rate (= full charge capacity after deterioration / new full charge capacity) over time, and the actual curve. Is the full charge capacity calculated from the usage state of the vehicle.

  The ideal curve is obtained in advance by changing the battery temperature and the SOC level correlated with the deterioration of the battery capacity. For example, FIG. 4A shows ideal curves when a battery having the same SOC is left in an environment at a temperature of 25 ° C. and when it is left in an environment at a temperature of 40 ° C. FIG. The graph shows an ideal curve when the battery is left in a state of SOC 90% and a case where the battery is left in a state of SOC 80% under the environment.

  The use state of the vehicle is a temperature environment to which the battery is actually exposed, an SOC state in which the battery is used, and the like. In vehicles, the history of the battery's temperature environment and SOC that changes every moment is stored using the measurement values of various sensors mounted on the vehicle, and the ideal full charge capacity is determined based on the temperature environment and the SOC usage ratio. Can be calculated. For example, if the period of exposure to the environment at a temperature of 25 ° C. and the period of exposure to the environment at a temperature of 40 ° C. in four years are almost the same (1: 1), FIG. The intermediate value (the fourth year) between the two ideal curves can be calculated as the ideal full charge capacity.

  The determination unit 41 determines whether the ideal full charge capacity calculated by the above-described method deviates from the current full charge capacity estimated in the previous process by a second predetermined value or more. The second predetermined value may be set to an appropriate value based on specifications and performance required for the vehicle. This divergence may be determined only by a simple difference between the current full charge capacity and the ideal full charge capacity calculated this time, or the transition of the current full charge capacity at each point in time estimated up to the previous time. It may be determined from the transition of the ideal full charge capacity calculated so far (FIG. 4C). Further, the full charge capacity obtained by resetting the difference obtained this time may be set as the current full charge capacity.

  If the difference between the current full charge capacity and the ideal full charge capacity is greater than or equal to the second predetermined value (S303, Yes), the process proceeds to step S304, where the current full charge capacity and the ideal full charge capacity are compared. If the difference is not greater than or equal to the second predetermined value (S303, No), the process ends.

(Step S304)
The determining 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 made so that the process of lowering the SOC of the second battery 22 required to secure ΔSOC can be performed without wastefully discarding the power of the second battery 22. In particular, since this processing is assumed to be performed in a state where the vehicle power supply is off, such as when parking, the role of restoring the SOC of the first battery 12 that has been self-discharged due to parking for a long period of time is also provided. Have.

  The third predetermined value is set based on whether or not power transfer from the second battery 22 to the first battery 12 described later can be efficiently performed. For example, if there is almost no voltage difference between the open-ended voltage of the second battery 22 and the open-ended voltage of the first battery 12, almost no current flows between the batteries, so that less power is transferred. The SOC of the battery 22 cannot be reduced efficiently. Therefore, the third predetermined value is set so that a certain voltage difference can be determined. The predetermined value is preferably set in consideration of a voltage drop due to a resistance value of a wiring path (such as a wire harness) from the second battery 22 to the first battery 12.

  If the open-ended voltage of the second battery 22 is higher than the open-ended voltage of the first battery 12 by a third predetermined value or more (S304, Yes), the process proceeds to step S305 to open the second battery 22. If the terminal voltage is not higher than the open terminal voltage of the first battery 12 by the third predetermined value or more (S304, No), the process returns to step S301.

(Step S305)
The power transfer unit 42 starts transferring power from the second battery 22 to the first battery 12. The power transfer is performed by turning on the second relay device 52 connecting the second battery 22 to the second power supply system, and connecting the first power supply system to the second power supply system. It can be started by turning on the relay device 51 of FIG.

(Step S306)
The determining unit 41 determines whether or not the SOC of the second battery 22 has become equal to or less than a fourth predetermined value. This determination is performed to determine whether or not the process of lowering the SOC of the second battery 22 necessary to secure ΔSOC has been completed. Therefore, the fourth predetermined value is set to an SOC that is smaller than the first predetermined value and is determined to be able to secure ΔSOC necessary for estimating the full charge capacity with high accuracy. In the lithium iron phosphate battery having the SOC-OCV characteristic illustrated in FIG. 2, SOC (for example, 30%) lower than the flat region can be set as the fourth predetermined value.

  Note that, instead of determining whether or not the SOC of the second battery 22 has become equal to or less than a fourth predetermined value, the determination unit 41 reduces the discharge current of the second battery 22 to be equal to or less than a fifth predetermined value. It may be determined whether or not it has become. By looking at the discharge current of the second battery 22, it can be determined that the power transfer has been performed such that the voltage difference between the open-ended voltage of the second battery 22 and the open-ended voltage of the first battery 12 disappears, This is because it is possible to indirectly determine that the second battery 22 has dropped to the SOC required to secure ΔSOC.

  When the 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) (S306, Yes), the process proceeds to step S307, and the process proceeds to step S307. If the SOC is not lower than the fourth predetermined value (or the discharge current is lower than the fifth predetermined value) (S306, No), the process of step S306 is repeatedly executed.

(Step S307)
The power transfer unit 42 ends the power transfer from the second battery 22 to the first battery 12. The power transfer is performed by turning off the second relay device 52 connecting the second battery 22 to the second power supply system or by connecting the first power supply system to the second power supply system. The process can be terminated by turning off one relay device 51.

(Step S308)
The determination unit 41 sets a flag for requesting execution of a predetermined full charge capacity estimation process to the ON state next time the vehicle is powered on (READY_ON or the like). The capacity estimating unit 43 checks this flag when the power of the vehicle is turned on, and if it is in the ON state, performs the process of estimating the full charge capacity of the second battery 22 using the secured ΔSOC with high accuracy. To be implemented. Then, when the capacity estimating unit 43 completes the process of estimating the full charge capacity of the second battery 22, the determination unit 41 sets the flag to the OFF state. Note that the process of estimating the full charge capacity can be performed using a well-known current integration method in a charging operation from a low SOC to a high SOC.

  When the power of the vehicle is turned on during the processing of steps S301 to S308, the flag for requesting the execution of the full charge capacity estimation processing is OFF, and thus the full charge capacity estimation processing is performed. Is not implemented. When the power of the vehicle is turned off next time, the processing of step S301 described above is started again.

<Second embodiment>
[Constitution]
FIG. 5 is a diagram illustrating a schematic configuration example of a power supply system 2 for a vehicle including a power supply control device 40 according to a second embodiment of the present invention. The power supply system 2 illustrated in FIG. 5 includes a first power supply system including a first DDC 11, a first battery 12, a first exercise system 13, and a load 14, a second DDC 21, and a second battery. 22, a second power system including a second exercise system 23, a power supply unit 30, and a power control device 40.

  The power supply system 2 employs a redundant power supply configuration including a first power supply system and a second power supply system. The first power supply system and the second power supply system are connected via a first relay device 51 for supplying dark current. The first power supply system and the second power supply system are connected via a third relay device 53 and a switching DCDC converter (hereinafter, referred to as “switching DDC”) 60. The second battery 22 is connected to the switching DDC 60 via a second relay device 52 for battery protection, and further connected to the second motor system 23 of the second power supply system via a fourth relay device 54. It is connected. 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 is controlled by the power supply control device 40.

  In the configuration of the power supply system 2 of the second embodiment, the power supply unit 30, the first DDC 11, the first exercise system 13, the load 14, and the second exercise system 23 are the same as those of the first embodiment. The description is omitted because it is the same as the power supply system 1 of the embodiment.

  The first battery 12 is a chargeable / dischargeable power storage element such as a lead battery. The first battery 12 can store (charge) the electric power output from the first DDC 11 and the electric power output from the second DDC 21, and can store the electric power stored by itself in the first exercise system. 13 and the load 14 (discharge).

  The second DDC 21 can convert the power supplied from the power supply unit 30 and output the converted power to the first battery 12, the first exercise system 13, and the load 14. Specifically, the second DDC 21 reduces the high-voltage power supplied from the power supply unit 30 to low-voltage power, and outputs the low-voltage power to the first battery 12, the first exercise system 13, and the load 14. I do.

  The second battery 22 is a chargeable / dischargeable power storage element such as a lithium ion battery. In the second embodiment, the second battery 22 is an iron phosphate-based lithium ion battery (LFP battery) having a flat region in SOC-OCV characteristics as shown in FIG. The second battery 22 can output (discharge) the power stored therein to the second exercise system 23 via the second relay device 52 and the fourth relay device 54. The second battery 22 has a role as a backup power supply for maintaining functions related to the motion of the vehicle when the first battery 12 fails during driving of the vehicle.

  The power control device 40 includes a first DDC 11, a second DDC 21, a first battery 12, a second battery 22, a first relay device 51, a second relay device 52, a third relay device 53, The state of the power supply system 2 can be controlled by managing the states and operations of the relay device 54 and the switching DDC 60. The power supply control device 40 of the second embodiment executes control for estimating the full charge capacity of the second battery 22 with high accuracy.

  The power supply control device 40 includes a determination unit 41, a power transfer unit 42, and a capacity estimation unit 43.

  The determination unit 41 determines whether it is necessary to correct the currently estimated full charge capacity when the state of charge (SOC) of the second battery 22 is equal to or more than the first predetermined value. Do. The determination unit 41 can be realized by, for example, a monitoring ECU (not shown) that can monitor the voltage, current, and temperature of the second battery 22 using a sensor or the like.

  When the determination unit 41 determines that the full charge capacity of the second battery 22 needs to be corrected, the power transfer unit 42 uses another battery that does not need to be corrected from the second battery 22 (the second battery 22). In the embodiment, a predetermined power is transferred to the first battery 12). Further, the power transfer unit 42 can also return the power from the first battery 12 to the second battery to be charged during the power transfer. The power transfer unit 42 includes, for example, a power supply ECU (not shown) that can control the 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 a monitoring ECU (not shown) that can control the connection state of the second relay device 52.

  The capacity estimation unit 43 performs a predetermined full charge capacity estimation process on the second battery 22 according to the power supply state of the vehicle. The capacity estimation unit 43 can be realized by, for example, a power supply ECU (not shown) that can control the output voltage of the switching DDC 60.

  Detailed control of the determination unit 41, the power transfer unit 42, and the capacity estimation unit 43 will be described later.

[control]
Next, control executed by the power supply control device 40 according to the second embodiment of the present invention will be described with further reference to FIGS. 6A and 6B. FIGS. 6A and 6B are flowcharts showing processing related to estimation of the full charge capacity of the second battery 22 performed by the power supply control device 40 according to the second embodiment. 6A and 6B of the second embodiment, steps that perform the same processing as the steps of the first embodiment shown in FIG. 3 are denoted by the same reference numerals and described. Omitted.

(Step S605)
If it is determined in step S <b> 304 that the open-ended voltage of the second battery 22 is higher than the open-ended voltage of the first battery 12 by a third predetermined value or more, the power transfer unit 42 outputs the second battery 22 from the second battery 22. Power transfer to the first battery 12 is started. The power transfer is performed by turning on the second relay device 52 connecting the second battery 22 to the second power supply system and connecting the third power supply system to the first power supply system. It can be started by turning on the relay device 53 and the switching DDC 60. At the same time, the capacity estimation unit 43 estimates 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 controlled by the switching DDC 60. To start. Since the open-end voltage and the transfer current can be accurately controlled by the switching DDC 60, the full charge capacity of the second battery 22 can be reduced by applying a well-known current integration method to the discharging operation from the high SOC to the low SOC. Highly accurate estimation can be performed.

(Step S607)
If it is determined in step S306 that the SOC of the second battery 22 has become equal to or less than the fourth predetermined value (or the discharge current has become equal to or less than the fifth predetermined value), the power transfer unit 42 outputs the second The power transfer to the first battery 12 is terminated. The power transfer is performed by turning off the second relay device 52 connecting the second battery 22 to the second power supply system or by connecting the first power supply system to the second power supply system. By turning off the relay device 53 and the switching DDC 60, the process can be terminated. Further, the capacity estimating unit 43 ends the process of estimating the full charge capacity of the second battery 22.

(Step S608)
The capacity estimating unit 43 determines whether or not the estimation of the full charge capacity of the second battery 22 has been completed by performing the power transfer. If the estimation of the full charge capacity is completed (S608, Yes), the process proceeds to step S609, and if the estimation of the full charge capacity is not completed (S608, No), the process proceeds to step S611.

(Step S609)
The power transfer unit 42 starts a process of charging the second battery 22 with the power of the first battery 12. This charging is performed to increase the SOC of the second battery 22 that has been reduced by the power transfer. The charge amount may be the entire amount of transferred power or a part of the amount of power. The charging process turns on the second relay device 52 connecting the second battery 22 to the second power supply system, and connects the third power supply system to the third power supply system. It can be started by turning on the relay device 53 and the switching DDC 60.

(Step S610)
The determining unit 41 determines whether the SOC of the second battery 22 has become equal to or greater than a sixth predetermined value. This determination is made to determine whether a sufficient amount of power has been returned to the second battery 22. Here, the sixth predetermined value, which is a sufficient amount of power, can be set to, for example, the amount of power (storage amount) necessary to back up functions related to the motion of the vehicle.

  If the SOC of the second battery 22 has become equal to or greater than the sixth predetermined value (S610, Yes), the process ends. If the SOC of the second battery 22 is not equal to or greater than the sixth predetermined value (S610, No), the process of step S610 is repeatedly executed.

(Step S611)
The determination unit 41 sets a flag for requesting execution of a predetermined full charge capacity estimation process to the ON state next time the vehicle is powered on (READY_ON or the like). The capacity estimating unit 43 checks this flag when the vehicle is turned on, and if the flag is turned on, performs the process of estimating the full charge capacity of the second battery 22 using the secured ΔSOC with high accuracy. To be implemented. Then, when the process of estimating the full charge capacity of the second battery 22 is completed by the capacity estimator 43, the determination unit 41 sets the flag to the OFF state. The process of estimating the full charge capacity can be performed using a known current integration method in the charging operation from low SOC to high SOC.

  When the power of the vehicle is turned on during the processing of steps S301 to S611, the flag for requesting the execution of the full charge capacity estimation processing is OFF, so that the full charge capacity estimation processing is performed. Is not implemented. When the power of the vehicle is turned off next time, the processing of step S301 described above is started again.

<Third embodiment>
[Constitution]
The power supply control device 40 according to the third embodiment has the same configuration as the power supply control device applied to the power supply system 1 of the first embodiment shown in FIG.

[control]
With reference to FIG. 7, control executed by the power supply control device 40 according to the third embodiment of the present invention will be described. FIG. 7 is a flowchart illustrating a process related to estimating the full charge capacity of the second battery 22 performed by the power supply control device 40 according to the third embodiment. The flowchart shown in FIG. 7 is obtained by further adding the determination in step S701 to the flowchart of the first embodiment shown in FIG. Note that steps other than step S701 in FIG. 7 are the same as the processing described in FIG. 3, and thus description thereof will be omitted.

(Step S701)
The determination unit 41 estimates the deterioration state of the full charge capacity of the second battery 22 based on the temperature of the second battery 22, and needs to correct the current full charge capacity based on the estimated deterioration state. It is determined whether or not. More specifically, the determination unit 41 determines that the time when the temperature of the second battery 22 becomes equal to or lower than the predetermined temperature, which is obtained from the predetermined battery temperature information, corresponds to the time from the start of use of the second battery 22. It is determined whether the ratio is equal to or less than a sixth predetermined value.

  Batteries, such as lithium ion batteries and lead batteries, have the property that battery degradation progresses at higher temperatures than at lower temperatures. For example, FIG. 8 shows the aging characteristics when batteries having the same amount of stored power (SOC) are left for a long time in an environment of 0 ° C., 10 ° C., 25 ° C., 45 ° C., 60 ° C., and 70 ° C. . As shown in FIG. 8, the capacity retention rate of a battery having the same charged amount is 93% after 240 days when the battery is left for a long time without any charging in a state where the environmental temperature of the battery is 0 ° C. However, if the battery is left for a long time without any charging in the state where the environmental temperature of the battery is 70 ° C., the deterioration proceeds to 62% after 120 days (× plot). Therefore, it is important for the battery to appropriately manage the environmental temperature.

In making the determination in step S701, the determination unit 41 accumulates the time spent in that state for each of predetermined temperature categories (B temperatures: Tb _{1 to} Tb _n ) as illustrated in FIG. 9 as the battery temperature information. The calculated “existence time” is calculated. The existence time may be only a time when the vehicle is used such as traveling, or may include a time when the vehicle is not used such as parking. The temperature division can be set arbitrarily, such as in units of 1 ° C. or 10 ° C. For example, FIG. 9 shows that the existing time during which the second battery 22 has been used at the temperature of Tb ₃ from the start of use of the vehicle to the present is t ₃ .

Next, the determination unit 41 divides the existence time for each temperature category shown in FIG. 9 by the elapsed time from the start of use of the vehicle to the present time, and as shown in FIG. The presence frequency (= existence time / elapsed time) is calculated for each (B temperature: Tb _{1 to} Tb _n ). For the elapsed time, the number of days calculated in step S302 can be used. The existence time and existence frequency described above may be calculated each time step S701 is executed, or may be calculated and stored sequentially during use of the vehicle. For example, FIG. 10 shows that the frequency of use of the second battery 22 at the temperature of Tb ₃ from the start of use of the vehicle to the present is p ₃ (= t ₃ / elapsed time). FIG. 11 shows a distribution image of the existence frequency (temperature frequency) of each temperature section obtained in this manner.

  Then, based on the obtained temperature frequency distribution, the determination unit 41 determines that the ratio of the time when the temperature of the second battery 22 is equal to or lower than the predetermined temperature to the time from the start of use of the second battery 22 is the sixth. Is determined to be less than or equal to a predetermined value. This determination is made to determine whether the time during which the second battery 22 has been used at a low temperature is long or short. When the second battery 22 has been used for a long time at a low temperature, it can be estimated that the progress of battery deterioration is slow, and when the second battery 22 has not been used for a long time at a low temperature, It can be estimated that the progress of battery deterioration is fast. Therefore, for example, it can be determined that the smaller the area of the hatched portion shown in FIG. 11 is, the more the battery may be deteriorated. The sixth predetermined value can be arbitrarily set according to the capacity and characteristics of the second battery 22.

  If the ratio of the time during which the temperature of the second battery 22 is equal to or lower than the predetermined temperature is equal to or lower than the sixth predetermined value (S701, Yes), the process proceeds to step S304, where the temperature of the second battery 22 is equal to or lower than the predetermined temperature. If the ratio of the time during which the temperature becomes equal to or lower than the predetermined temperature does not become equal to or lower than the sixth predetermined value (S701, No), the present process ends.

<Fourth embodiment>
[Constitution]
The power supply control device 40 according to the fourth embodiment has the same configuration as the power supply control device applied to the power supply system 2 of the second embodiment shown in FIG.

[control]
FIG. 12 is a flowchart illustrating a part of a process related to estimating the full charge capacity of the second battery 22 performed by the power supply control device 40 according to the fourth embodiment of the present invention. The flowchart shown in FIG. 12 is obtained by further adding the determination in step S701 described in the third embodiment to the flowchart of the second embodiment shown in FIG. 6A. In step S701, the determination unit 41 estimates the deterioration state of the full charge capacity of the second battery 22 based on the temperature of the second battery 22, and corrects the current full charge capacity based on the estimated deterioration state. Determine if it is necessary to do so. More specifically, the determination unit 41 determines that the ratio of the time when the temperature of the second battery 22 is equal to or lower than the predetermined temperature to the time from the start of use of the second battery 22 is equal to or less than the sixth predetermined value. It is determined whether or not there is.

  Steps other than step S701 in FIG. 12 are the same as the processing described in FIG. 6A. The connectors A, B, and C in FIG. 12 are connected to the connectors A, B, and C in the flowchart of the second embodiment illustrated in FIG. 6B.

<Modification>
In the third and fourth embodiments, step S701 is added to steps S302 and S303 to determine whether it is necessary to correct the currently estimated full charge capacity. Alternatively, it may be determined only at steps S302 and S701 whether the currently estimated full charge capacity needs to be corrected.

<Action and effect>
According to the power supply control device 40 according to the embodiment of the present invention described above, it is necessary to correct the full charge capacity when the power storage amount is equal to or more than the predetermined value (first predetermined value) at the timing when the vehicle is turned off. The power of a certain target battery (second battery 22) is transferred to another battery (first battery 12) to lower the power to a predetermined low SOC. Then, at the next timing when the power of the vehicle is turned on, charging is performed with a wide SOC width from a low SOC to a high SOC, and the full charge capacity of the target battery is calculated based on the current integration method. As a result, the process of estimating the full charge capacity of the battery can be performed at a suitable timing. In particular, by securing a large ΔSOC, the influence of measurement errors such as current and voltage by the sensor can be suppressed, and the full charge capacity of the target battery can be estimated with high accuracy.

  Further, in the power supply control device 40 according to the present embodiment, based on whether a predetermined number of days has elapsed since the date when the full charge capacity of the battery was last estimated, or based on the deterioration state of the full charge capacity of the battery. Then, it is determined whether or not the full charge capacity needs to be corrected. The deterioration state is estimated based on whether or not the difference between the 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 more than a predetermined value (a second predetermined value). . By considering the difference between the full charge capacities, it is possible to accurately determine the necessity of correcting the full charge capacities. Further, the deterioration state is estimated based on whether or not the ratio of the time when the temperature of the battery is equal to or lower than the predetermined temperature to the time from the start of use of the battery is equal to or lower than a predetermined value (sixth predetermined value). . By considering the temperature of the battery as described above, it is possible to more appropriately determine the necessity of correcting the full charge capacity. These determinations can reduce the power consumption required for the full charge capacity estimation process. Prohibition time can be reduced.

  Further, in the power supply control device 40 according to the present embodiment, when the open-end voltage of the target battery is higher than the open-end voltage of the non-target battery by a predetermined value (third predetermined value) or more, the target battery is switched to another battery. Transfer predetermined power. This can avoid inefficient power transfer. In addition, when the amount of charge of the target battery falls below a predetermined value (fourth predetermined value) or the current value discharged from the target battery falls below a predetermined value (fifth predetermined value), power transfer is performed. finish. Thereby, useless power transfer can be avoided. In addition, since the process of estimating the full charge capacity is performed without performing the power transfer for the battery having the charged amount less than the predetermined value (the first predetermined value), the trouble of the power transfer can be omitted.

  Furthermore, in the power supply control device 40 according to the present embodiment, if the first battery 12 and the second battery are connected by the switching DDC 60 that can accurately control the current, the second battery 22 By applying a well-known current integration method to the discharging action from high SOC to low SOC that occurs when power is transferred to the first battery 12, the full charge capacity of the second battery 22 can be estimated with high accuracy. .

  Although the embodiment of the present invention has been described above, the present invention relates to a power supply control device, a power supply system for a vehicle including the power supply control device, a method of estimating a full charge capacity executed by the power supply control device, and an estimation of a full charge capacity. It can be regarded as a program and a computer-readable non-transitory recording medium storing the program, or a vehicle equipped with a power control device.

  INDUSTRIAL APPLICABILITY The power supply control device of the present invention can be used for a vehicle equipped with a power supply system having two power supply systems.

1, 2 Power supply system 11, 21, 60 DCDC converter (DDC)
12, 22 Battery 13, 23 Motor system 14 Load 30 Power supply unit 40 Power control unit 41 Judgment unit 42 Power transfer unit 43 Capacity estimation unit 51, 52, 53, 54 Relay device

Claims (9)

A power supply control device for estimating a full charge capacity of a battery mounted on a vehicle,
A determination unit configured to determine whether it is necessary to correct the currently estimated full charge capacity when the power storage amount of the battery is equal to or more than a first predetermined value at a timing when the vehicle is turned off. ,
A power transfer unit that transfers predetermined power from the battery to another battery when it is determined that the battery needs to be corrected by the determination unit;
At a timing when the power of the vehicle is turned on after the power transfer by the power transfer unit or during the power transfer by the power transfer unit, a capacity estimation unit that performs a predetermined full charge capacity estimation process on the battery; A power control device.   The determining unit is configured to determine whether the full charge capacity needs to be corrected based on whether a predetermined number of days has elapsed since the last time the full charge capacity of the battery was estimated by the capacity estimation unit. The power supply control device according to claim 1, which makes a determination.   The method according to claim 1, wherein the determining unit estimates a state of deterioration of the full charge capacity of the battery, and determines whether it is necessary to correct the full charge capacity based on the estimated state of deterioration. The power supply control device as described in the above.   The determination unit is configured to determine the state of deterioration based on whether a difference between a full charge capacity obtained from a predetermined aging deterioration curve and a full charge capacity estimated by the capacity estimation unit is equal to or greater than a second predetermined value. The power supply control device according to claim 3, wherein   The determination unit is configured to determine whether a ratio of a time when the temperature of the battery is equal to or lower than the predetermined temperature to a time from the start of use is equal to or less than a sixth predetermined value, which is obtained from predetermined battery temperature information. The power supply control device according to claim 3, wherein the power supply control device estimates the deterioration state.   The power transfer unit may transfer predetermined power from the battery to the other battery when an open-ended voltage of the battery is higher than an open-ended voltage of the other battery by a third predetermined value or more. The power supply control device according to any one of claims 1 to 5.   The power transfer unit is configured to determine whether the amount of stored power in the battery is equal to or less than a fourth predetermined value that is smaller than the first predetermined value, or when the current value discharged from the battery is equal to or less than a fifth predetermined value. 7. The power supply control device according to claim 1, wherein the power transfer is terminated.   2. The full charge capacity estimating process is performed at a timing when the power of the vehicle is turned on, without making a determination by the determining unit, when the charged amount of the battery is less than the first predetermined value. The power supply control device according to claim 1.   8. The battery according to claim 1, wherein when the estimation of the full charge capacity of the battery is completed by the power transfer by the power transfer unit, the battery is charged with at least a part of the power transferred to the another battery. 9. Power control device.

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