JP2015233390A - Charge control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge control apparatus capable of preventing deterioration of a charging efficiency in charging an auxiliary-equipment battery with power supplied from a main battery when an ignition of an electric vehicle is turned off for preventing the auxiliary-equipment battery from being exhausted.SOLUTION: A charge control apparatus includes: a main battery for supplying power to a motor being a drive source of a vehicle; an auxiliary-equipment battery for supplying power to auxiliary equipment of the vehicle; a DC-DC converter for stepping down a voltage of the main battery to supply power to the auxiliary-equipment battery; and a control part for causing the DC-DC converter to operate to charge the auxiliary-equipment battery until recovering to a given SOC when a given period of time has elapsed after an ignition of the vehicle is turned off. Further, the give period of time is changed on the basis of a history of a charge amount by the charging.

Description

  The present invention relates to an auxiliary battery charge control device mounted on an electric vehicle.

  An electric vehicle using a motor (electric motor) as a driving force source includes an auxiliary battery having a voltage lower than that of the main battery in addition to a high-voltage main battery that supplies electric power to the motor. In many cases, power is supplied to electronic control devices) and electrical components).

  Therefore, when the ignition is off (parking), the amount of power stored in the auxiliary battery decreases due to dark current or the like, and if the auxiliary battery goes up, it is impossible to supply power to the ECU that performs start control of the electric vehicle. The electric vehicle cannot be started.

  Therefore, conventionally, in an electric vehicle such as a hybrid vehicle, there is a case where the auxiliary battery is charged by transmitting power from the main battery to the auxiliary battery after a certain time has elapsed since the ignition switch is turned off (for example, Patent Document 1). Thereby, it is possible to prevent the auxiliary battery of the electric vehicle from going up when the ignition is off (parking).

JP 2006-174619 A

  However, after a certain period of time has elapsed since the ignition switch is turned off, the auxiliary battery is uniformly charged, and the charging efficiency may deteriorate. For example, if the remaining capacity of the auxiliary battery after a lapse of a certain time after the ignition switch is turned off is close to full charge than expected, the charge acceptability of the auxiliary battery is reduced. When the auxiliary battery is charged, the charging efficiency may deteriorate.

  Accordingly, in view of the above problem, in order to prevent the auxiliary battery from rising, it is possible to prevent deterioration of charging efficiency when the auxiliary battery is charged by supplying power from the main battery when the ignition of the electric vehicle is turned off. An object of the present invention is to provide a simple charge control device.

In order to solve the above problem, in one embodiment, the charging control device includes:
A main battery that supplies power to a motor that is a driving force source of the vehicle;
An auxiliary battery for supplying electric power to the auxiliary machine of the vehicle;
A DC-DC converter that steps down the voltage of the main battery and supplies power to the auxiliary battery;
A controller that operates the DC-DC converter and charges the auxiliary battery until the vehicle returns to a predetermined SOC when a predetermined time has elapsed after the vehicle ignition is turned off, and
The predetermined time is
It is changed based on the charge amount history at the time of charging.

  According to the above embodiment, in order to prevent the auxiliary battery from rising, charging capable of preventing deterioration of charging efficiency when the auxiliary battery is charged by supplying power from the main battery when the ignition of the electric vehicle is turned off. A control device can be provided.

It is a block diagram which shows an example of a structure of the vehicle containing the charge control apparatus which concerns on this embodiment. It is a flowchart which shows an example of the charge control process of the auxiliary battery at the time of the ignition-off of the vehicle by the charge control apparatus (ECU) which concerns on 1st Embodiment. It is a figure explaining the determination method of the next predetermined parking time (time until it starts charge of an auxiliary machine battery after ignition-off) by ECU. It is a flowchart which shows an example of the charge control process and deterioration determination process of an auxiliary machine battery at the time of the ignition-off of the vehicle by the charge control apparatus (ECU) which concerns on 2nd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram illustrating a configuration of a vehicle 1 including a charge control device 2 according to the present embodiment. In addition, a continuous line shows an electric power supply system, and a dashed-dotted line represents a control transmission system.

  The vehicle 1 is an electric vehicle that uses a motor 10 as a driving force source. The motor 10 generates driving force by three-phase AC power supplied from a high-voltage battery 30 via an inverter 20. The vehicle 1 is configured to be able to charge the high voltage battery 30 from the external power source 100. That is, the vehicle 1 is, for example, a plug-in hybrid vehicle or an electric vehicle using only the motor 10 as a driving force source.

  The charging control apparatus 2 according to the present embodiment includes a high voltage battery 30, a DC-DC converter 40, an auxiliary battery 50, an ECU 60, and the like, and an auxiliary battery by supplying power from the high voltage battery 30 via the DC-DC converter 40. Control 50 charging.

  The high-voltage battery 30 is a high-voltage power storage device that supplies electric power to the motor 10 and has a terminal voltage of several hundred volts (for example, 288 V). The electric power from the high-voltage battery 30 is supplied to the motor 10 (inverter 20) as it is, or the voltage is boosted. For the high voltage battery 30, for example, an arbitrary power storage device that can supply electric power for driving the motor 10, such as a nickel metal hydride battery or a lithium ion battery, may be applied. The high voltage battery 30 is configured to be able to supply power to the auxiliary battery 50. Specifically, the DC-DC converter 40 is operated by a command from the ECU 60, and power can be supplied from the high voltage battery 30 to the auxiliary battery 50 via the DC-DC converter 40.

  The high voltage battery 30 includes a monitoring unit 31 that monitors the state of the high voltage battery 30. The monitoring unit 31 includes, for example, various sensors that measure the current, voltage, temperature, and the like of the high-voltage battery 30. Moreover, the monitoring unit 31 calculates the state of the high-voltage battery 30 (SOC (State Of Charge), SOH (State Of Health)) based on the detection values of various sensors. Including equipment. The output of the monitoring unit 31 (the output of various sensors included, the calculation result of the processing device, etc.) is output to the ECU 60.

  As described above, the high voltage battery 30 can be charged by supplying power from the external power supply 100. The external power supply 100 may be a direct current power supply or an alternating current power supply. When the external power supply 100 is an alternating current power supply, alternating current is converted into direct current between the connection paths of the external power supply 100 and the high voltage battery 30. An AC / DC converter is arranged. The AC / DC converter may be provided on the vehicle 1 side, or may be provided on the external power supply 100 side (for example, a charging stand).

  The DC-DC converter 40 is a power conversion device that steps down the voltage of the high-voltage battery 30 reaching several hundred volts to about 12 to 14 V and supplies power to the auxiliary battery 50. The DC-DC converter 40 includes, for example, a conversion circuit using a power switching element that converts direct current from the high-voltage battery 30 to alternating current, a transformer that steps down the alternating current, a diode that rectifies and smoothes the reduced alternating current, and a smoothing filter. (Inductors, capacitors).

  The auxiliary battery 50 is a low-voltage power storage device that supplies electric power to auxiliary machines (for example, various ECUs including the ECU 60, electric components such as wipers, lighting, and air conditioning) mounted on the vehicle 1, and has a voltage of about 12 to 14V. Terminal voltage. As the auxiliary battery 50, for example, an arbitrary power storage device that can supply electric power to an auxiliary machine mounted on the vehicle 1, such as a lead battery, may be applied. In the drawing, the power supply path from the auxiliary battery 50 to the ECU 60 is omitted for convenience.

  Auxiliary battery 50 includes a sensor 51. The sensor 51 includes a voltage sensor and a current sensor that measure the voltage and current of the auxiliary battery 50, and the measurement result is output to the ECU 60.

  The ECU 60 is a main control unit in the charging control device 2. That is, the ECU 60 is an electronic control unit that controls charging of the auxiliary battery 50 by supplying power from the high voltage battery 30 to the auxiliary battery 50, and includes a nonvolatile internal memory 61. For example, the ECU 60 is configured by a microcomputer or the like, and may execute various control processes described later by executing various programs stored in the ROM on the CPU. Specifically, the ECU 60 transmits an operation signal to the DC-DC converter 40 and operates the DC-DC converter 40 to charge the auxiliary battery 50 from the high voltage battery 30. More specifically, an operation signal from the ECU 60 is input to a drive circuit that drives the conversion circuit of the DC-DC converter 40, and the drive circuit drives a switching element of the conversion circuit in accordance with the operation signal, and the DC-DC Converter 40 may be activated. When a predetermined time (predetermined parking time N) elapses after an ignition switch (not shown) of the vehicle 1 is turned off, the ECU 60 operates the DC-DC converter 40 to charge the auxiliary battery 50. The details of the charging control (charging control of the auxiliary battery 50 when the ignition of the vehicle 1 is turned off) will be described later.

  Note that the ECU 60 may appropriately charge the auxiliary battery 50 by operating the DC-DC converter 40 so that the auxiliary battery 50 is included in a predetermined charging state when the ignition of the vehicle 1 is on. . For example, when the auxiliary battery 50 is a lead battery, it is desirable that the auxiliary battery 50 is in a state that is nearly fully charged from the viewpoint of preventing deterioration. In this case, the ECU 60 operates the DC-DC converter 40 based on the output from the sensor 51 or the like so that the SOC of the auxiliary battery 50 is included in a predetermined range close to full charge, and the auxiliary battery 50 The charging control may be performed. Also, in the case where the auxiliary battery 50 is a lithium ion battery, a predetermined SOC range determined from the viewpoint of preventing deterioration is set similarly to the lead battery, and the ECU 60 is configured so that the SOC is included in the predetermined range. In addition, charging control of the auxiliary battery 50 may be performed.

  Next, charging control of the auxiliary battery 50 when the vehicle 1 is turned off (IG-OFF) by the charging control device 2 according to the present embodiment will be described.

  FIG. 2 is a flowchart showing an example of charge control processing of the auxiliary battery 50 when the ignition control of the vehicle 1 is turned off by the charge control device 2 (ECU 60) according to the present embodiment. The flowchart is executed every time the ignition switch of the vehicle 1 is turned off (IG-OFF).

  Referring to FIG. 2, in step S101, counting of the parking time (elapsed time from IG-OFF) by the internal timer is started.

  In step S102, it is determined whether the parking time by the internal timer has reached the predetermined parking time N, that is, whether the predetermined parking time N has elapsed since IG-OFF. The predetermined parking time N is determined as the predetermined parking time N in the next process according to the flowchart as described later in the flowchart, and is stored in advance in the internal memory 61 at the start of the process according to the flowchart. If the predetermined parking time N has elapsed since IG-OFF, the process proceeds to step S104. If the predetermined parking time N has not elapsed since IG-OFF, the process proceeds to step S103.

  In step S103, it is determined whether or not the ignition switch is turned on (IG-ON). If the IG-ON is set, the current process is terminated. If the IG-ON is not set, the process returns to step S102.

  That is, in steps S102 and S103, the vehicle 1 remains in the IG-OFF state, waits for the elapsed time from the IG-OFF to pass the predetermined parking time N, and remains in the IG-OFF state, and the elapsed time from the IG-OFF. When the predetermined parking time N has elapsed, the process proceeds to step S104. On the other hand, if the IG-ON is performed before the elapsed time from the IG-OFF reaches the predetermined parking time N, the current process is terminated.

  In step S104, based on the output from the monitoring unit 31, it is determined whether or not the remaining capacity of the high voltage battery 30 is greater than or equal to a predetermined amount TH1. For example, the determination may be made based on the SOC information of the high voltage battery 30 output from the processing device of the monitoring unit 31 (It may be determined whether the SOC of the high voltage battery 30 is equal to or higher than a predetermined SOCth corresponding to the predetermined amount TH1). . The determination may be made based on the voltage information of the high voltage battery 30 output from the voltage sensor of the monitoring unit 31 (that is, whether or not the voltage V of the high voltage battery 30 is equal to or higher than the predetermined voltage Vth corresponding to the predetermined amount TH1). You may). When the remaining capacity of the high voltage battery 30 is equal to or greater than the predetermined amount TH1, the process proceeds to step S105, and when it is less than the predetermined amount TH1, the current process is terminated. This is because if the auxiliary battery 50 is charged in step S105 described later in a state where the remaining capacity of the high-voltage battery 30 is low, the high-voltage battery 30 may rise.

  When the high-voltage battery 30 is being charged by supplying power from the external power supply 100, the determination process in step S104 may be skipped, or the case where the high-voltage battery 30 is not charged is The fixed amount TH1 may be set small. This is because when the high voltage battery 30 is being charged, the possibility that the high voltage battery 30 will rise is extremely low.

  In step S105, the DC-DC converter is operated and charging of the auxiliary battery 50 is started.

  In step S106, based on the output from the sensor 51 (the output from the current sensor that measures the current of the auxiliary battery 50), the charge amount from the start of charging is integrated.

  In step S107, it is determined whether charging of the auxiliary battery 50 is completed. If the charging is not completed, the integration of the charge amount from the start of charging of the auxiliary battery 50 in step S106 is continued until the charging is completed. Then, when the charging of the auxiliary battery 50 is completed, the process proceeds to step S108.

  Completion of charging of auxiliary battery 50 is determined by whether or not the SOC of auxiliary battery 50 has returned to a predetermined SOC. For example, when the auxiliary battery 50 is a lead battery, it may be determined that the charging of the auxiliary battery 50 is completed when a state of charge determined to be fully charged (for example, SOC = 90%) is reached. When auxiliary battery 50 is a lithium ion battery, it may be determined that charging of auxiliary battery 50 has been completed when a predetermined SOC (for example, SOC = 80%) that is less than full charge is reached. Specifically, based on an output from the sensor 51 (an output from a current sensor that measures the current of the auxiliary battery 50), a state where the current during charging of the auxiliary battery 50 is equal to or lower than a predetermined current value Ith is predetermined. When continuing for time T or more, it may be determined that charging is completed.

  In step S108, the current charge amount X accumulated from the start of charging to the completion of charging in step S106 is compared with the average charge amount Y in the charging according to the flowchart for the past n times until the previous time.

  Note that the ECU 60 determines that the charge amount accumulated from the start of charging until the completion of charging is the current charge amount X at the time when it is determined in step S107 that the charging of the auxiliary battery 50 has been completed. 61 is stored.

  In step S109, based on the comparison between the current charge amount X in step S108 and the average charge amount Y for the past n times, the predetermined parking time N (hereinafter simply referred to as the next predetermined parking time N) in the process according to the next flowchart. Call).

  In step S110, the average charge amount Y is updated, and the current process ends. That is, in the next process according to the flowchart, in order to perform the comparison (step S108), the average charge amount Y for n times including the charge of the auxiliary battery 50 according to the current flowchart is calculated as the average charge amount Y. This processing is terminated.

  Next, a method for determining the next predetermined parking time N (the time until the auxiliary battery 50 starts to be charged after the ignition is turned off), which corresponds to steps S108 and S109 in the above-described flowchart (FIG. 2), is specifically described. Explain.

  FIG. 3 is a diagram for explaining a method for determining the next predetermined parking time N (time until ignition of the auxiliary battery is started after the ignition is turned off) by the ECU 60. FIG. 3A shows a table for determining the next predetermined parking time N based on the comparison result between the current charge amount X and the average charge amount Y for the past n times until the previous time. Specifically, the relationship between the current charge amount X and the average charge amount Y for the past n times is shown in the left column, and the next predetermined parking time N corresponding to the right column is shown. FIG. 3B is a diagram visually showing the relationship between the current charge amount X and the next predetermined parking time N on the number line of the charge amount X.

  Note that comparison amounts Z1 to Z6 for comparing the current charge amount X and the average charge amount Y are set, and these relationships are Z1> Z2> Z3> 0 and 0 <Z4 <Z5 <Z6. is there. In addition, assuming that the current predetermined parking time is N0, reduction times N1 to N3 indicating a reduction amount of the next predetermined parking time N with respect to the current predetermined parking time N0, and additional times N4 to N6 indicating additional portions are set. These relationships are N1> N2> N3> 0 and 0 <N4 <N5 <N6.

  Referring to FIG. 3A, when the current charge amount X is equal to or greater than the average charge amount Y plus the comparison amount Z1 (X ≧ Y + Z1), the next predetermined parking time N is determined as the current predetermined parking amount. The time is determined by subtracting the reduction time N1 from the time N0 (N = N0−N1).

  If the current charge amount X is equal to or larger than the amount obtained by adding the comparison amount Z2 to the average charge amount Y and smaller than the amount obtained by adding the comparison amount Z1 to the average charge amount Y (Y + Z2 ≦ X <Y + Z1), The parking time N is determined as a time (N = N0−N2) obtained by subtracting the reduction time N2 from the current predetermined parking time N0.

  Further, when the current charge amount X is equal to or larger than the amount obtained by adding the comparison amount Z3 to the average charge amount Y and smaller than the amount obtained by adding the comparison amount Z2 to the average charge amount Y (Y + Z3 ≦ X <Y + Z2), The parking time N is determined as a time (N = N0−N3) obtained by subtracting the reduction time N3 from the current predetermined parking time N0.

  In addition, when the current charge amount X is smaller than the amount obtained by adding the comparison amount Z3 to the average charge amount Y and larger than the amount obtained by subtracting the comparison amount Z4 from the average charge amount Y (Y−Z4 <X <Y + Z3), The next predetermined parking time N remains the current predetermined parking time N0 (N = N0).

  Further, when the current charge amount X is equal to or less than the amount obtained by subtracting the comparison amount Z4 from the average charge amount Y and greater than the amount obtained by subtracting the comparison amount Z5 from the average charge amount Y (YZ5 <X ≦ Y−Z4). The next predetermined parking time N is determined as a time (N = N0 + N4) obtained by adding the addition time N4 to the current predetermined parking time N0.

  Further, when the current charge amount X is equal to or less than the amount obtained by subtracting the comparison amount Z5 from the average charge amount Y and greater than the amount obtained by subtracting the comparison amount Z6 from the average charge amount Y (YZ6 <X ≦ Y−Z5). The next predetermined parking time N is determined as a time (N = N0 + N5) obtained by adding the addition time N5 to the current predetermined parking time N0.

  In addition, when the current charge amount X is equal to or less than the average charge amount Y minus the comparison amount Z6 (X ≦ Y−Z6), the next predetermined parking time N is added from the current predetermined parking time N0 to the additional time N6. Is determined as the time (N = N0 + N6).

  In summary, as shown in FIG. 3B, when the current charge amount X is greater than the average charge amount Y (more than a predetermined amount), the next predetermined parking time N is determined to be shorter than the current predetermined parking time N0. (Be changed. At this time, the next predetermined parking time N is determined (changed) so as to become shorter as the current charging amount X increases.

  When the current charge amount X is smaller (predetermined or more) than the average charge amount Y, the next predetermined parking time N is determined (changed) to be longer than the current predetermined parking time N0. At this time, the next predetermined parking time N is determined (changed) so as to increase as the current charge amount X decreases.

  Next, the operation of the charge control device 2 (ECU 60) according to this embodiment will be described.

  As described above, when the predetermined parking time N elapses after the IG-OFF, the ECU 60 charges the auxiliary battery 50 until it returns to a predetermined SOC (for example, full charge when the auxiliary battery 50 is a lead battery). I do. Here, the ECU 60 stores the charge amount (current charge amount X) by the charge in the internal memory 61 every time, and determines (changes) the (next) predetermined parking time N based on the charge amount history by the charge. ) Specifically, the charge amount X of the current charge (the latest) and the average charge amount Y (the average value for the predetermined number n) of the past n charge amounts of the charge until the previous time (before the latest). A (next) predetermined parking time N is determined (changed) based on the comparison. Thereby, the deterioration of the charge efficiency in charge of the auxiliary battery 50 performed when predetermined time (predetermined parking time N) passes after IG-OFF can be suppressed. In addition, it is possible to suppress the deterioration of the auxiliary battery 50 accompanying the suppression of the deterioration of the charging efficiency. That is, the deterioration of the charging efficiency can be suppressed while the deterioration of the auxiliary battery 50 is suppressed. Hereinafter, the operation will be described in detail.

  When the auxiliary battery 50 is charged, the remaining capacity (SOC) of the auxiliary battery 50 may be reduced to some extent from full charge in order to improve the charge acceptance of the auxiliary battery 50 and improve the charging efficiency. desirable. On the other hand, when the remaining capacity (SOC) of the auxiliary battery 50 decreases below a certain level, the deterioration of the auxiliary battery 50 is promoted. Therefore, the remaining capacity (SOC) of the auxiliary battery 50 exceeds the level at which the deterioration is not promoted. It is desirable to be held on. That is, it is desirable that the remaining capacity (SOC) of the auxiliary battery 50 when starting to charge the auxiliary battery 50 be within a predetermined range from the viewpoint of charging efficiency and suppression of deterioration.

  Here, assuming that the predetermined parking time N is constant, when the charging of the auxiliary battery 50 is started when the predetermined parking time N has elapsed since IG-OFF, the auxiliary battery at the start of charging is determined. There is a possibility that the remaining capacity (SOC) of 50 has not decreased to the predetermined range. As a result, the charge acceptance of the auxiliary battery 50 may decrease, and the charging efficiency may decrease. Similarly, assuming that the predetermined parking time N is constant, if the charging of the auxiliary battery 50 is started when the predetermined parking time N has elapsed since IG-OFF, the auxiliary battery at the start of charging There is a possibility that the remaining capacity (SOC) of 50 exceeds the predetermined range and decreases. As a result, the deterioration of the auxiliary battery 50 may be promoted.

  On the other hand, the charge control device 2 (ECU 60) according to the present embodiment determines (changes) the (next) predetermined parking time N based on the history of the amount of charge by the charge. Specifically, the (next) predetermined parking time N is determined (changed) based on a comparison between the current charge amount X and the average charge amount Y for the past n times until the previous time. The charge amount due to the charge is considered to be the discharge amount at the time of IG-OFF (parking), and corresponds to the remaining capacity (SOC) of the auxiliary battery 50, so based on the history of the charge amount (discharge amount), It is possible to set a predetermined parking time N in consideration of charging efficiency and suppression of deterioration of the auxiliary battery 50.

  Specifically, the current charge start relative to the average remaining capacity of the auxiliary battery 50 at the start of the past n times of the charge by comparing the current charge amount X and the average charge amount Y of the past n times until the previous time. The increase / decrease in the remaining capacity of the auxiliary battery 50 at the time can be seen. The increase (decrease) in the remaining capacity of the auxiliary battery 50 at the start of the current charging relative to the average remaining capacity of the auxiliary battery 50 at the start of the charging for the past n times is the change in the auxiliary battery 50 at the start of the current charging. It can be considered that the remaining capacity indicates the degree of deviation from the predetermined range. Therefore, even if the remaining capacity of the auxiliary battery 50 is the same as this time by increasing / decreasing the predetermined parking time N according to the increase / decrease (deviation) of the current charge amount X with respect to the average charge amount Y, the next time The remaining capacity of the auxiliary battery 50 at the start of charging can be kept within the predetermined range. That is, it is possible to prevent deterioration of the charging efficiency during charging while suppressing deterioration of the auxiliary battery 50.

  In the example of FIG. 3, when the current charge amount X is larger than the average charge amount Y, the next predetermined parking time N is determined (changed) to be shorter than the current predetermined parking time N0. At this time, the next predetermined parking time N is determined (changed) so as to become shorter as the current charging amount X increases. Here, the fact that the current charge amount X is larger than the average charge amount Y indicates that the remaining capacity of the auxiliary battery 50 has decreased from the average remaining capacity up to the previous time at the start of the current charge. Therefore, at least the next predetermined parking time N is made shorter than the current predetermined parking time N0, thereby preventing the remaining capacity of the auxiliary battery 50 from exceeding the predetermined range and reducing the deterioration of the auxiliary battery 50. Progress can be suppressed. Further, as the current charge amount X increases away from the average charge amount Y, the remaining capacity of the auxiliary battery 50 at the start of the current charge decreases away from the average remaining capacity of the auxiliary battery 50 up to the previous time. . Therefore, as the current charge amount X increases, the next predetermined parking time N is shortened to better prevent the remaining capacity of the auxiliary battery 50 from decreasing beyond the predetermined range. The progress of deterioration of the auxiliary battery 50 can be suppressed.

  In the example of FIG. 3, when the current charge amount X is smaller than the average charge amount Y, the next predetermined parking time N is determined (changed) to be longer than the current predetermined parking time N0. At this time, the next predetermined parking time N is determined (changed) to become longer as the current charge amount X decreases. Here, the fact that the current charge amount X is smaller than the average charge amount Y indicates that the remaining capacity (SOC) of the auxiliary battery 50 is increased from the average remaining capacity up to the previous time at the start of the current charge. . Therefore, by making at least the next predetermined parking time N longer than the current predetermined parking time N0, it is possible to suppress deterioration in charging efficiency at the time of the subsequent charging. Further, as the current charge amount X decreases away from the average charge amount Y, the remaining capacity of the auxiliary battery 50 at the start of the current charge increases away from the previous average remaining capacity of the auxiliary battery 50. . For this reason, as the current charge amount X decreases, the next predetermined parking time N becomes longer, so that deterioration of the charging efficiency at the time of the subsequent charge can be suppressed.

  In addition, the charge control device 2 according to the present embodiment performs charge control based on the charge amount of the auxiliary battery 50 (accumulation of current by the current sensor), and the auxiliary battery 50 is in the IG-OFF state of the vehicle 1. There is no need to measure the remaining capacity (SOC) itself. That is, in the present embodiment, the deterioration of the auxiliary battery 50 is suppressed without using a battery sensor or the like that measures the remaining capacity (SOC) of the auxiliary battery 50 when the vehicle 1 is parked (IG-OFF). In addition, the charging efficiency can be increased. Therefore, it is possible to suppress an increase in cost.

  When the vehicle 1 is a new vehicle, that is, when the history of the charge amount due to the charging of the auxiliary battery 50 shown in FIG. 2 does not exist in the internal memory 61, the charging efficiency of the auxiliary battery 50 and the suppression of deterioration are considered. The set time may be used as the predetermined parking time N. For example, the capacity of the auxiliary battery 50 in the new state, the dark current of the vehicle 1 (note that the dark current when the vehicle 1 is IG-OFF can be set in advance as a predetermined value through experiments, simulations, etc.) Based on this, an initial value of the predetermined parking time N may be set. Then, after the charge amount history is accumulated to some extent (n times or more), the above-described method for determining the predetermined parking time N may be used.

  Further, in the example of FIG. 3, when the current charge amount X is larger than the average charge amount Y, the predetermined parking time N is determined (changed) so as to be shortened step by step as the current charge amount X increases. However, you may determine (change) so that it may become short continuously in at least one part. Similarly, in the example of FIG. 3, when the current charge amount X is smaller than the average charge amount Y, the predetermined parking time N is determined (changed) so as to increase stepwise as the current charge amount X decreases. However, you may determine (change) so that it may become long continuously in at least one part.

  In the example of FIG. 3, the next predetermined parking time N is determined (changed) based on the previous predetermined parking time N0. For example, the average value of the predetermined parking times for the past n times (average) (Predetermined parking time) The next predetermined parking time N may be determined (changed) based on Nave. That is, the next predetermined parking time N may be determined (changed) based on the history of the predetermined parking time determined in the past (to this time).

  Moreover, in this embodiment, when the predetermined parking time N passed from IG-OFF, the auxiliary battery 50 was charged. However, once the parking time has been extended for a long time, the auxiliary battery 50 is charged once. However, the remaining capacity of the auxiliary battery 50 may decrease again. Therefore, after completion of charging of the auxiliary battery 50 performed in the IG-OFF state of the vehicle 1, when the IG-OFF state continues and the predetermined parking time N has elapsed, as in the above-described embodiment, The auxiliary battery 50 may be charged until it returns to the predetermined SOC.

  Also in this case, the charging control process by the ECU 60 described with reference to FIG. 2 may be executed, and the predetermined parking time N determination method described with reference to FIG. 3 may be applied. Thereby, the deterioration of the charging efficiency at the time of the said charge can be suppressed, suppressing the same effect | action and effect, ie, deterioration of the auxiliary battery 50. In this case, in addition to the case where the IG-OFF is performed, the flowchart of FIG. 2 completes the charging of the auxiliary battery 50 (according to the flowchart of FIG. 2) when the vehicle 1 is IG-OFF, and the IG-OFF state It is also executed for cases where the process continues.

[Second Embodiment]
Next, a second embodiment will be described.

  The charge control device 2 according to the present embodiment differs from the first embodiment in that a deterioration determination process for the auxiliary battery 50 is performed in addition to the charge control process described in the first embodiment. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and different portions will be mainly described.

  Hereinafter, the deterioration determination process of the auxiliary battery 50 by the charge control device 2 (ECU 60) according to the present embodiment will be described. Note that an example of the configuration of the charging control device 2 according to the present embodiment is illustrated in FIG. 1 as in the first embodiment, and thus description thereof is omitted.

  FIG. 4 is a flowchart showing an example of charge control processing and deterioration determination processing of the auxiliary battery 50 when the ignition of the vehicle 1 is turned off by the charge control device 2 (ECU 60) according to the present embodiment. The flowchart is executed every time the ignition switch of the vehicle 1 is turned off (IG-OFF).

  The charge control process (steps S201 to S210) of the auxiliary battery 50 is the same as that in the first embodiment (steps S101 to S110 in FIG. 2), and thus the description thereof will be omitted and the description will be focused on step S211 and subsequent steps. To do.

  Referring to FIG. 4, in step S <b> 211, the amount of discharge A during the current parking (IG-OFF) is calculated. For example, the discharge amount A can be calculated as follows. Discharge amount A [Ah] = dark current I [A] of vehicle 1 × predetermined parking time N0 [h]. Note that the dark current when the vehicle 1 is IG-OFF can be set in advance as a predetermined value through experiments, simulations, or the like.

  In step S212, whether or not the discharge amount A at the time of the current parking is larger than the average charge amount Y for n times (the average charge amount Y updated in step S210) according to this flowchart including the current time (steps S201 to S210). Determine. If the discharge amount A during the current parking is larger than the average charge amount Y, the process proceeds to step S213. If the discharge amount A during the current parking is equal to or less than the average charge amount Y, the current process is terminated.

  In step S213, the deterioration predictor flag is stored in the internal memory 61. That is, when the charge amount thereafter is smaller than the discharge amount of the auxiliary battery 50, it is highly possible that the auxiliary battery 50 is deteriorated and the capacity of the auxiliary battery 50 to be stored is reduced. However, it is difficult to determine the tendency even if the amount of discharge and the amount of charge are compared. Therefore, when the discharge amount A is compared with the average charge amount Y for n times including this time, and the discharge amount A is larger than the average charge amount Y, it is assumed that the auxiliary battery 50 has a tendency to deteriorate, and the deterioration sign is The flag is stored in the internal memory 61.

  In step S214, it is determined whether or not the number of times the deterioration predictor flag is stored in the internal memory 61 is equal to or greater than the predetermined number m1 (≦ m0) out of the predetermined number m0 of the deterioration determination process according to the flow including the current time. To do. When the number of times the deterioration predictor flag is stored in the internal memory 61 is equal to or greater than the predetermined number m1 among the predetermined number m0, the process proceeds to step S215, and when the number is less than the predetermined number m1, the current process is terminated.

  In step S215, the deterioration determination of the auxiliary battery 50 is finalized. That is, the auxiliary battery 50 determines that the battery has deteriorated, stores the deterioration flag in the internal memory 61, and ends the current process.

  As described above, the charging control device 2 according to the present embodiment executes the deterioration determination of the auxiliary battery 50 in addition to the charging control. Specifically, first, a deterioration sign is determined, and it is determined that there is a deterioration sign when the discharge amount A at the time of parking this time is larger than the average charge amount Y for n times including this time (stores a deterioration sign flag). ) Then, when the deterioration sign determination is performed a predetermined number m0 times including this time, if it is determined that there is a deterioration sign more than the predetermined number m1 times (a deterioration sign flag is stored), the auxiliary battery 50 is deteriorated. (Deterioration flag is stored). As a result, the deterioration of the auxiliary battery 50 can be determined when the auxiliary battery 50 is charged at the time of IG-OFF. Therefore, the deterioration of the auxiliary battery 50 is notified to the user by an indicator or the like at the next start of the vehicle 1. can do. Therefore, the user can take measures such as replacing the auxiliary battery 50 at an early stage, and prevents the vehicle 1 from suddenly becoming unstartable by proceeding without knowing that the auxiliary battery 50 has deteriorated. be able to.

  As in the first embodiment, after completion of charging of the auxiliary battery 50 performed when the vehicle 1 is IG-OFF, the IG-OFF state continues and the predetermined parking time N elapses. The auxiliary battery 50 may be charged until the SOC is restored. In this case, in addition to the case where the IG-OFF is performed, the flowchart of FIG. 4 completes the charging of the auxiliary battery 50 (according to the flowchart of FIG. 4) when the vehicle 1 is IG-OFF, and the IG-OFF state continues. It is also executed when it is.

  As mentioned above, although the form for implementing this invention was explained in full detail, this invention is not limited to this specific embodiment, In the range of the summary of this invention described in the claim, various Can be modified or changed.

  For example, in the above-described embodiment, the vehicle 1 is an electric vehicle capable of charging the high-voltage battery 30 by supplying power from the external power supply 100, but is not limited to this configuration. The vehicle 1 may be an electric vehicle (a so-called hybrid vehicle) that cannot charge the high voltage battery 30 by the external power source 100. Also in this case, the charge control process for the auxiliary battery 50 similar to that in the above-described embodiment may be applied, and the same actions and effects are achieved.

  Further, in the above-described embodiment, the charge control process when charging the auxiliary battery by supplying power from the main battery (power storage device that supplies power to the motor) mounted on the electric vehicle has been described. The application of processing is not limited to these. For example, the charging is also applied to a fuel cell vehicle or an engine vehicle (a vehicle having only the engine as a driving power source) provided with a dedicated regenerative power storage device (for example, a lithium ion battery) that stores regenerative power during regenerative braking. Control processing may be applied. That is, the charging control process may be applied to charging of the auxiliary battery by supplying power from the regeneration power storage device. Even in this case, the same operations and effects as the above-described embodiment are obtained.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Charge control apparatus 10 Motor 20 Inverter 30 High voltage battery (main battery)
31 Monitoring Unit 40 DC-DC Converter 50 Auxiliary Battery 51 Sensor 60 ECU (Control Unit)
61 Internal memory 100 External power supply

Claims (5)

A main battery that supplies power to a motor that is a driving force source of the vehicle;
An auxiliary battery for supplying electric power to the auxiliary machine of the vehicle;
A DC-DC converter that steps down the voltage of the main battery and supplies power to the auxiliary battery;
A controller that operates the DC-DC converter and charges the auxiliary battery until the vehicle returns to a predetermined SOC when a predetermined time has elapsed after the vehicle ignition is turned off, and
The predetermined time is
It is changed based on the history of the charge amount by the charge,
Charge control device. The controller is
After completion of charging of the auxiliary battery performed in the ignition-off state of the vehicle, when the ignition-off state of the vehicle continues and the predetermined time has elapsed, the DC-DC converter is operated, The auxiliary battery is charged until returning to the predetermined SOC,
The charge control device according to claim 1. The predetermined time is
It is characterized in that it is changed based on a comparison between a charge amount by the most recent charge and an average value for a predetermined number of charge amounts by the charge before the most recent charge,
The charge control apparatus according to claim 1 or 2. The predetermined time is
When the most recent charge amount is greater than the average value, the charge amount is changed to be shorter than the predetermined time determined most recently, and when the most recent charge amount is less than the average value, the predetermined time determined most recently It is changed to be longer,
The charge control device according to claim 3. The predetermined SOC is
The auxiliary battery is in a charged state that is determined to be fully charged,
The charge control apparatus according to any one of claims 1 to 4.

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