JP7092013B2 - Power control unit - Google Patents

Description

The present invention relates to a power supply control device that estimates the full charge capacity of a battery mounted on a vehicle.

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

Japanese Unexamined Patent Publication No. 2013-101072

In a battery having a flat region of SOC-OCV characteristics such as an iron phosphate lithium-ion battery (see FIG. 2), it is difficult to determine the amount of electricity stored (SOC) from the open end voltage (OCV), so the current integration method is used. It is conceivable to calculate the SOC by. Here, since the full charge capacity required for SOC calculation by the current integration method is a value that changes as the battery deteriorates, it is desirable to increase the frequency of estimation processing and obtain the latest value as much as possible. ..

However, in the method described in Patent Document 1, the full charge capacity estimation process is performed only at a limited opportunity such as the timing of 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, but the method described in Patent Document 1 ensures ΔSOC because external charging is performed as a matter of course. Is not enough. Therefore, there is room for improvement in the timing and method of performing the full charge capacity estimation process.

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

In order to solve the above problems, one aspect of the present invention is a power supply control device that estimates the full charge capacity of a battery mounted on a vehicle, and when the power of the vehicle is turned off, the amount of electricity stored in the battery is reduced. When it is equal to or more than the first predetermined value, the judgment unit determines whether or not the currently estimated full charge capacity needs to be corrected, and when the judgment unit determines that it needs to be corrected, the battery A power transfer unit that transfers a predetermined power from one to another battery, and a predetermined charge for the battery at the timing when the vehicle is turned on after the power transfer by the power transfer unit or during the power transfer by the power transfer unit. It is provided with a capacity estimation unit that performs charge capacity estimation processing.

According to the power supply control device of the present invention, it is possible to carry out the estimation process of the full charge capacity of the battery at an appropriate timing and method.

The figure which shows the schematic configuration example of the power-source system including the power-source control device which concerns on 1st Embodiment. The figure which shows an example of the SOC-OCV characteristic of a lithium ion battery. A flowchart showing a procedure for processing related to estimation of the full charge capacity of the battery performed by the power supply control device according to the first embodiment. Figure showing an example of the ideal curve of battery capacity deterioration The figure which shows the schematic configuration example of the power-source system including the power-source control device which concerns on 2nd Embodiment. A flowchart showing a procedure of processing related to estimation of the full charge capacity of the battery performed by the power supply control device according to the second embodiment. A flowchart showing a procedure for processing related to estimation of the full charge capacity of the battery performed by the power supply control device according to the second and fourth embodiments. A flowchart showing a procedure for processing related to estimation of the full charge capacity of the battery performed by the power supply control device according to the third embodiment. The figure which shows an example of the aged deterioration characteristic when the environmental temperature of a battery is changed. The figure which shows the example which calculated the existence time for each temperature of a battery The figure which shows the example which calculated the existence frequency for each temperature of a battery. The figure which graphed the existence frequency of each temperature of the battery of FIG. A flowchart showing a procedure for processing related to estimation of the full charge capacity of the battery performed by the power supply control device according to the fourth embodiment.

<Overview>
The power 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 of the vehicle is turned off, and lowers 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 the current integration method using a large SOC width. This makes it possible to estimate the full charge capacity with high accuracy.

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

This power supply system 1 employs a redundant power supply configuration consisting of 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 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.

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

The first DDC 11 can convert the electric power supplied from the electric power supply unit 30 and output it to the first battery 12, the first kinetic system 13, and the load 14. Specifically, the first DDC 11 steps down the high voltage power supplied from the power supply unit 30 to a low voltage power and outputs it to the first battery 12, the first kinetic system 13, and the load 14. do.

The first battery 12 is a chargeable and 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 also outputs (discharges) the electric power stored by itself to the first kinetic system 13 and the load 14. be able to.

The first kinetic system 13 includes an in-vehicle device involved in the movement (running, turning, stopping) of the vehicle. The first kinetic system 13 includes, for example, devices such as steering, braking, and automatic driving support.

The load 14 includes one or more in-vehicle devices that are not involved in the movement of the vehicle. The load 14 includes devices such as headlamps and wipers as an example.

The second DDC 21 can convert the electric power supplied from the electric power supply unit 30 and output it to the second battery 22 and the second kinetic system 23. Specifically, the second DDC 21 steps down the high voltage power supplied from the power supply unit 30 to a low voltage power and outputs the high voltage power to the second battery 22 and the second kinetic system 23.

The second battery 22 is a chargeable and 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 electric power output from the second DDC 21 via the second relay device 52, and the electric power stored by itself can be stored in the second kinetic system. It can be output (discharged) to 23. The second battery 22 has a role as a backup power source for maintaining the function related to the movement of the vehicle when the failure of the first battery 12 occurs while the vehicle is driving.

The second kinetic system 23 is redundantly provided with the same system as the first kinetic system 13, and includes an in-vehicle device related to the movement of the vehicle like the first kinetic system 13. ..

The power supply 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. Therefore, the state of the power supply system 1 can be controlled. In the power supply control device 40 of the first embodiment, control for estimating the full charge capacity with high accuracy is executed for the second battery 22.

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

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

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) capable of controlling the output voltage of the second DDC 21.

The detailed control of the determination unit 41, the power transfer unit 42, and the capacity estimation unit 43 will be described below.

[control]
Next, with reference to FIGS. 3 and 4, the control executed by the power supply control device 40 according to the first embodiment of the present invention will be described. FIG. 3 is a flowchart showing a process related to 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 showing an example of an ideal curve of battery capacity deterioration.

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

(Step S301)
The determination unit 41 determines whether or not the SOC of the second battery 22 is equal to or higher than the first predetermined value. This judgment is made to determine whether or not it is necessary to intentionally lower the SOC of the second battery 22 in order to secure ΔSOC that enhances the estimation accuracy in carrying out the estimation process of the full charge capacity. Will be. Therefore, the first predetermined value is set to the SOC that is determined to be able to secure the ΔSOC required for estimating the full charge capacity with high accuracy. In the iron phosphate-based lithium ion battery having the SOC-OCV characteristics exemplified 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, Yes). S301, No), the process proceeds to step S308.

(Step S302)
The determination unit 41 determines whether or not a predetermined number of days or more have passed from the day when the current full charge capacity of the second battery 22 is estimated (the last estimated processing day). This determination is made to determine whether or not it is necessary to correct (review) the current full charge capacity due to the deterioration of the second battery 22 over time. The predetermined number of days can be arbitrarily set to an appropriate value based on the usage environment of the vehicle and the like, but can be 30 days as an example.

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

(Step S303)
The determination unit 41 estimates the deterioration state of the full charge capacity of the second battery 22, and determines whether or not it is necessary to correct the current full charge capacity based on the estimated deterioration state. More specifically, the determination unit 41 determines whether or not the deviation between the current full charge capacity estimated in the previous process and the ideal full charge capacity is equal to or greater than the second predetermined value. The ideal full charge capacity is the aged deterioration curve (ideal curve) of the battery capacity, which shows the change in the battery capacity retention rate (= full charge capacity after deterioration / full charge capacity of a new product) with the passage of time, and the actual It is the full charge capacity calculated from the usage status of the vehicle.

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

The usage state of the vehicle is the temperature environment in which the battery is actually exposed, the state of the SOC in which the battery is used, and the like. In the vehicle, the battery temperature environment and SOC history that change from moment to moment are saved using the measured values of the various sensors installed in the vehicle, and the ideal full charge capacity is based on the temperature environment and SOC usage ratio. Can be calculated. For example, if the period of exposure to the environment of 25 ° C. and the period of exposure to the environment of 40 ° C. for 4 years are approximately the same ratio (1: 1), it is shown in FIG. 4 (a). The intermediate value (4th year) of the two ideal curves can be calculated as the ideal full charge capacity.

The determination unit 41 determines whether or not the ideal full charge capacity calculated by the above method and the current full charge capacity estimated in the previous process deviate from each other by a second predetermined value or more. The second predetermined value may be set to an appropriate value based on the specifications and performance required for the vehicle. This deviation may be judged only by the 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 time point estimated up to the previous time. , It may be judged from the transition of the ideal full charge capacity calculated so far (FIG. 4 (c)). Further, the full charge capacity obtained by resetting the dissociation difference obtained this time may be set as the current full charge capacity.

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

(Step S304)
The determination unit 41 determines whether or not the open end voltage (OCV) of the second battery 22 is larger than the open end 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 necessary for securing ΔSOC can be performed without wasting the power of the second battery 22. In particular, since this process is assumed to be performed when the vehicle power is off, such as when parking, it also has the role of recovering the SOC of the first battery 12 that has self-discharged due to long-term parking. Have.

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

When the open end voltage of the second battery 22 is larger than the open end voltage of the first battery 12 by a third predetermined value or more (S304, Yes), the process proceeds to step S305 and the second battery 22 is released. When the end voltage is not larger than the open end voltage of the first battery 12 by a third predetermined value or more (S304, No), the process returns to step S301.

(Step S305)
The power transfer unit 42 starts power transfer from the second battery 22 to the first battery 12. For power transfer, the first relay device 52 connecting the second battery 22 to the second power system is turned on, and the first power system and the second power system are connected to each other. It can be started by turning on the relay device 51 of.

(Step S306)
The determination unit 41 determines whether or not the SOC of the second battery 22 is equal to or less than the fourth predetermined value. This determination is made to determine whether or not the process of lowering the SOC of the second battery 22 required to secure ΔSOC has been completed. Therefore, the fourth predetermined value is set to the SOC, which is smaller than the first predetermined value and is judged to have secured the ΔSOC necessary for estimating the full charge capacity with high accuracy. In the iron phosphate-based lithium ion battery having the SOC-OCV characteristics exemplified in FIG. 2, the SOC (for example, 30%) lower than the flat region can be set as the fourth predetermined value.

In addition, instead of determining whether or not the SOC of the second battery 22 is equal to or less than the fourth predetermined value, the determination unit 41 makes the discharge current of the second battery 22 equal to or less than the fifth predetermined value. You may judge 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 so that the voltage difference between the open end voltage of the second battery 22 and the open end 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.

If 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 second battery 22 If the SOC is not less than or equal to the fourth predetermined value (or the discharge current is not less than or equal to 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. For power transfer, the second relay device 52 connecting the second battery 22 to the second power system is turned off, or the first power system and the second power system are connected to each other. It can be terminated by turning off the relay device 51 of 1.

(Step S308)
The determination unit 41 sets a flag in the ON state for requesting the execution of a predetermined full charge capacity estimation process the next time the vehicle is turned on (READY_ON, etc.). If the capacity estimation unit 43 confirms this flag when the power of the vehicle is turned on and is in the ON state, the capacity estimation unit 43 accurately estimates the full charge capacity of the second battery 22 using the secured ΔSOC. To carry out. Then, the determination unit 41 sets the flag to the OFF state when the capacity estimation unit 43 completes the estimation process of the full charge capacity of the second battery 22. The full charge capacity estimation process can be performed by using a well-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 process of steps S301 to S308 described above, the flag for requesting the execution of the full charge capacity estimation process is OFF, so that the full charge capacity estimation process is performed. Will not be implemented. The next time the vehicle is turned off, the process of step S301 described above is restarted.

<Second embodiment>
[Constitution]
FIG. 5 is a diagram showing 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 kinetic system 13, and a load 14, a second DDC 21, and a second battery. 22. A second power supply system including a second kinetic system 23, a power supply unit 30, and a power supply control device 40 are provided.

The power supply system 2 employs a redundant power supply configuration consisting of 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. Further, 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 is further connected to the second kinetic system 23 of the second power system via the 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.

Among the configurations of the power supply system 2 of the second embodiment, the power supply unit 30, the first DDC 11, the first kinetic system system 13, the load 14, and the second kinetic system system 23 are the above-mentioned first embodiment. Since it is the same as the power supply system 1 of the embodiment, the description thereof will be omitted.

The first battery 12 is a chargeable and 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 the electric power stored by itself can be stored in the first kinetic system. It can be output (discharged) to 13 and the load 14.

The second DDC 21 can convert the electric power supplied from the electric power supply unit 30 and output it to the first battery 12, the first kinetic system 13, and the load 14. Specifically, the second DDC 21 steps down the high voltage power supplied from the power supply unit 30 to a low voltage power and outputs it to the first battery 12, the first kinetic system 13, and the load 14. do.

The second battery 22 is a chargeable and 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 electric power stored by itself to the second kinetic 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 source for maintaining the function related to the movement of the vehicle when the failure of the first battery 12 occurs while the vehicle is driving.

The power supply 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, and a second. It is possible to control the state of the power supply system 2 by managing the state and operation of the relay device 54 of 4 and the switching DDC 60. In the power supply control device 40 of the second embodiment, control for estimating the full charge capacity with high accuracy is executed for the second battery 22.

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

When the power transfer unit 42 determines in the determination unit 41 that the full charge capacity of the second battery 22 needs to be corrected, the power transfer unit 42 does not need to correct the full charge capacity of the second battery 22 from the second battery 22 (this second battery). In the embodiment, a predetermined power is transferred to the first battery 12). Further, the power transfer unit 42 can also return power from the first battery 12 to the second battery to charge it during this power transfer. The power transfer unit 42 can control, for example, 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 (not shown). ), A monitoring ECU (not shown) capable of controlling the connection state of the second relay device 52, and the like.

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) capable of controlling the output voltage of the switching DDC 60.

The detailed control of the determination unit 41, the power transfer unit 42, and the capacity estimation unit 43 will be described below.

[control]
Next, with reference to FIGS. 6A and 6B, the control executed by the power supply control device 40 according to the second embodiment of the present invention will be described. 6A and 6B are flowcharts showing the processing 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 second embodiment. Of the steps shown in FIGS. 6A and 6B of the second embodiment, the steps that perform the same processing as the steps shown in FIG. 3 of the first embodiment will be described with the same numbers. It is omitted.

(Step S605)
When it is determined in step S304 that the open end voltage of the second battery 22 is larger than the open end voltage of the first battery 12 by a third predetermined value or more, the power transfer unit 42 is the second from the second battery 22. The power transfer of 1 to the battery 12 is started. For power transfer, a third relay device 52 connecting the second battery 22 to the second power system is turned on, and the first power system and the second power system are connected to each other. It can be started by turning on the relay device 53 and the switching DDC 60 of. 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 controlled by the switching DDC 60 to the first battery 12. To start. Since the open-end voltage and transfer current can be accurately controlled by the switching DDC 60, the full charge capacity of the second battery 22 can be increased by applying the well-known current integration method to the discharge action from high SOC to low SOC. Highly accurate estimation can be performed.

(Step S607)
When it is determined in step S306 that 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), the power transfer unit 42 moves from the second battery 22 to the second. The power transfer to the battery 12 of 1 is completed. For power transfer, the second relay device 52 connecting the second battery 22 to the second power system is turned off, or the first power system and the second power system are connected to each other. It can be terminated by turning off the relay device 53 and the switching DDC 60 of 3. Further, the capacity estimation unit 43 ends the process of estimating the full charge capacity of the second battery 22.

(Step S608)
The capacity estimation unit 43 determines whether or not the estimation of the full charge capacity of the second battery 22 is completed by carrying out 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 the process of charging the second battery 22 with the power of the first battery 12. This charge is performed to increase the SOC of the second battery 22, which has been reduced by the power transfer. The charge amount may be the total amount of electric power transferred or a partial amount of electric power. In the charging process, the second relay device 52 connecting the second battery 22 to the second power supply system is turned on, and the first power supply system and the second power supply system are connected to each other. It can be started by turning on the relay device 53 and the switching DDC 60 of.

(Step S610)
The determination unit 41 determines whether or not the SOC of the second battery 22 is equal to or higher than the 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 electric power amount, can be set to, for example, the electric power amount (storage amount) required for backing up the function related to the movement of the vehicle.

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

(Step S611)
The determination unit 41 sets a flag in the ON state for requesting the execution of a predetermined full charge capacity estimation process the next time the vehicle is turned on (READY_ON, etc.). If the capacity estimation unit 43 confirms this flag when the power of the vehicle is turned on and is in the ON state, the capacity estimation unit 43 accurately estimates the full charge capacity of the second battery 22 using the secured ΔSOC. To carry out. Then, the determination unit 41 sets the flag to the OFF state when the capacity estimation unit 43 completes the estimation process of the full charge capacity of the second battery 22. The full charge capacity estimation process can be performed by using a well-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 process of steps S301 to S611 described above, the flag for requesting the execution of the full charge capacity estimation process is OFF, so that the full charge capacity estimation process is performed. Will not be implemented. The next time the vehicle is turned off, the process of step S301 described above is restarted.

<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, the 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 showing a process related to estimation of 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 judgment of step S701 to the flowchart of the first embodiment shown in FIG. Since the steps other than step S701 in FIG. 7 are the same as the processes described in FIG. 3, the description here will be omitted.

(Step S701)
It is necessary for the determination unit 41 to estimate the deteriorated state of the full charge capacity of the second battery 22 based on the temperature of the second battery 22, and to correct the current full charge capacity based on the estimated deterioration state. Judge whether or not. More specifically, the determination unit 41 relates to the time from the start of use of the second battery 22 for the time when the temperature of the second battery 22 is equal to or lower than the predetermined temperature, which is obtained from the predetermined battery temperature information. It is determined whether or not the ratio is equal to or less than the sixth predetermined value.

A battery made of a lithium ion battery, a lead battery, or the like has a characteristic that the deterioration of the battery progresses at a high temperature rather than at a low temperature. For example, FIG. 8 shows the aged deterioration characteristics when batteries having the same storage capacity (SOC) are left in an environment of 0 ° C., 10 ° C., 25 ° C., 45 ° C., 60 ° C., and 70 ° C. for a long period of time, respectively. .. As shown in FIG. 8, the capacity retention rate of batteries having the same storage capacity is 93% after 240 days when the batteries are left for a long time without being charged at all with the environmental temperature of the batteries set to 0 ° C. However, if the battery is left at 70 ° C for a long period of time without being charged at all (○ plot), the deterioration progresses to 62% after 120 days (× plot). Therefore, it is important to properly manage the environmental temperature of the battery.

In making the determination in step S701, the determination unit 41 accumulates the time in that state for each preset temperature category (B temperature: Tb ₁ to Tb _n ) as illustrated in FIG. 9 as battery temperature information. Calculate the "existence time". The existence time may be only the time when the vehicle is used such as running, or may include the time when the vehicle is not used such as parking. The temperature classification can be arbitrarily set such as 1 ° C. unit or 10 ° C. unit. For example, FIG. 9 shows that the existence time of the second battery 22 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, and divides the existence time into each of the temperature categories as illustrated in FIG. 10 as battery temperature information. The existence frequency (= existence time / elapsed time) for each (B temperature: Tb ₁ to Tb _n ) is calculated. The number of days calculated in step S302 can be used as the elapsed time. The above-mentioned existence time and existence frequency may be calculated each time step S701 is executed, or may be sequentially calculated and stored while the vehicle is in use. For example, FIG. 10 shows that the frequency of existence of the second battery 22 used 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 of the temperature categories obtained in this way.

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

When the ratio of the time during which the temperature of the second battery 22 becomes equal to or lower than the predetermined temperature is equal to or less than the sixth predetermined value (S701, Yes), the process proceeds to step S304, and the temperature of the second battery 22 becomes predetermined. When the ratio of the time during which the temperature becomes equal to or less than the sixth predetermined value does not become equal to or less than the sixth predetermined value (S701, No), this 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 showing a part of the 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 fourth embodiment of the present invention. The flowchart shown in FIG. 12 is a flowchart of the second embodiment shown in FIG. 6A with the determination of step S701 described in the third embodiment further added. 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 you need to. More specifically, the determination unit 41 determines that the ratio of the time during which the temperature of the second battery 22 becomes 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. Determine if it exists.

The steps other than step S701 in FIG. 12 are the same as the processes described in FIG. 6A. Further, the combiners A, B, and C in FIG. 12 are coupled to the combiners A, B, and C in the flowchart of the second embodiment shown in FIG. 6B.

<Modification example>
In the third and fourth embodiments, step S701 is further added to steps S302 and 303 to determine whether or not it is necessary to correct the currently estimated full charge capacity. In addition to this, it may be determined only in steps S302 and S701 whether or not it is necessary to correct the currently estimated full charge capacity.

<Action / 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 a predetermined value (first predetermined value) at the timing when the power of the vehicle is turned off. The power of one target battery (second battery 22) is transferred to another battery (first battery 12) to reduce the SOC to a predetermined low SOC. Then, at the timing when the power of the vehicle is turned on next time, charging is performed with a wide SOC width from low SOC to high SOC, and the full charge capacity of the target battery is calculated based on the current integration method. As a result, it is possible to carry out the estimation process of the full charge capacity of the battery at an appropriate timing. In particular, by ensuring 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 or not a predetermined number of days have passed from the day 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. To determine if the full charge capacity needs to be modified. The deterioration state is estimated based on whether or not the deviation between the full charge capacity obtained from the predetermined deterioration curve and the full charge capacity estimated by the capacity estimation unit is equal to or more than a predetermined value (second predetermined value). .. By considering the deviation of the full charge capacity in this way, it is possible to accurately determine the necessity of correcting the full charge capacity. Further, the deterioration state is estimated based on whether or not the ratio of the time when the battery temperature becomes lower than the predetermined temperature to the time from the start of use of the battery is equal to or lower than the predetermined value (sixth predetermined value). .. By considering the temperature of the battery in this way, it is possible to more preferably determine the necessity of correcting the full charge capacity. Based on these judgments, it is possible to reduce the power consumption required for the full charge capacity estimation process, and in vehicles equipped with an automatic driving function, automatic operation due to a decrease in the battery charge during the full charge capacity estimation process is performed. The prohibition time can be shortened.

Further, in the power supply control device 40 according to the present embodiment, when the open end voltage of the target battery is larger than the open end voltage of the non-target battery by a predetermined value (third predetermined value) or more, the target battery is transferred to another battery. Transfer a given amount of power. This avoids inefficient power transfer. Further, when the amount of electricity stored in the target battery becomes equal to or less than a predetermined value (fourth predetermined value) or the current value discharged from the target battery becomes equal to or less than a predetermined value (fifth predetermined value), power transfer is performed. finish. This makes it possible to avoid unnecessary power transfer. For a battery whose storage amount is less than a predetermined value (first predetermined value), the full charge capacity estimation process is performed without performing power transfer, so that the labor of power transfer can be saved.

Further, in the power supply control device 40 according to the present embodiment, if the first battery 12 and the second battery are connected by a switching DDC 60 capable of accurately controlling the current, the second battery 22 to the second battery 22 are connected. It is also possible to estimate the full charge capacity of the second battery 22 with high accuracy by applying a well-known current integration method to the discharge action from high SOC to low SOC that occurs when the power of 1 is transferred to the battery 12. ..

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

The power supply control device of the present invention can be used for a vehicle or the like 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 device 41 Judgment unit 42 Power transfer unit 43 Capacity estimation unit 51, 52, 53, 54 Relay device

Claims (9)

It is a power supply control device that estimates the full charge capacity of the battery installed in the vehicle.
When the power of the vehicle is turned off and the stored amount of the battery is equal to or higher than the first predetermined value, it is determined whether or not it is necessary to correct the currently estimated full charge capacity of the battery . Judgment department and
When the determination unit determines that it is necessary to correct the full charge capacity of the battery, a power transfer unit that transfers a predetermined power from the battery to another battery, and a power transfer unit.
A capacity estimation unit that performs a predetermined full charge capacity estimation process on the battery at the 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. Prepare ,
Whether or not the determination unit needs to correct the full charge capacity of the battery based on whether or not a predetermined number of days have elapsed from the day when the full charge capacity of the battery was last estimated by the capacity estimation unit. Judging whether
When the determination unit determines that the full charge capacity of the battery needs to be corrected, the power transfer unit reduces the amount of electricity stored in the battery to a fourth predetermined value or less, which is smaller than the first predetermined value. A power control device that transfers the predetermined power from the battery to the other battery until it becomes . It is a power supply control device that estimates the full charge capacity of the battery installed in the vehicle.
When the power of the vehicle is turned off and the stored amount of the battery is equal to or higher than the first predetermined value, it is determined whether or not it is necessary to correct the currently estimated full charge capacity of the battery. Judgment department and
When the determination unit determines that it is necessary to correct the full charge capacity of the battery, a power transfer unit that transfers a predetermined power from the battery to another battery, and a power transfer unit.
A capacity estimation unit that performs a predetermined full charge capacity estimation process on the battery at the 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. Prepare,
The determination unit estimates the deterioration state of the fully charged capacity of the battery, determines whether or not it is necessary to correct the fully charged capacity based on the estimated deterioration state, and determines whether or not the fully charged capacity needs to be corrected.
When the determination unit determines that the full charge capacity of the battery needs to be corrected, the power transfer unit reduces the amount of electricity stored in the battery to a fourth predetermined value or less, which is smaller than the first predetermined value. A power control device that transfers the predetermined power from the battery to the other battery until it becomes. The determination unit further estimates the deterioration state of the full charge capacity of the battery, and determines whether or not it is necessary to correct the full charge capacity of the battery based on the estimated deterioration state. The power supply control device according to 1 . The determination unit determines the deterioration state based on whether or not the deviation between the full charge capacity obtained from the predetermined aging deterioration curve and the full charge capacity estimated by the capacity estimation unit is equal to or greater than the second predetermined value. The power supply control device according to claim 2 or 3 , wherein the power control device is estimated. The determination unit is based on whether or not the ratio of the time during which the temperature of the battery becomes equal to or lower than the predetermined temperature to the time from the start of use, which is obtained from the predetermined battery temperature information, is equal to or less than the sixth predetermined value. The power supply control device according to claim 2 or 3 , wherein the deterioration state is estimated. The power transfer unit transfers a predetermined power from the battery to the other battery when the open end voltage of the battery is larger than the open end voltage of the other battery by a third predetermined value or more. The power supply control device according to any one of 1 to 5. The power supply control device according to claim 6 , wherein the power transfer unit ends the power transfer when the current value discharged from the battery becomes equal to or less than a fifth predetermined value. 1 Or the power supply control device according to 2 . Any of claims 1 to 7, 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 other battery. The power supply control device according to item 1 .

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