JP2015058818A - Device for controlling battery in vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling a battery in a vehicle, that can prohibit SOC (state of charge) extension control at a suitable timing at which the battery can be charged with more regenerative power if suitable SOC extension control is executed, in consideration of a deterioration state of the battery, thereby achieve a maximum utilization of a battery capacity for the improvement in fuel consumption .SOLUTION: When execution requirements for SOC extension control are satisfied on the basis of a descending road prediction, an SOC control range RNGbase set in accordance with a new battery 11 is extended by a predetermined extended width Ex. An SOC control range RNGext after the extension is corrected in an expansion direction on the basis of a deterioration index of the battery 11 at that time. Thus, SOC extension control is executed while the SOC control range RNGext after the extension is being held within an approximately constant width as an absolute quantity regardless of a deterioration of the battery 11. Meanwhile, an upper allowance LMTup and a lower allowance LMTlo are preset as a percentage to a total capacity of the battery 11, and the SOC control range RNGext after the extension is restricted on the basis of these allowances LMTup, LMTlo.

Description

  The present invention relates to a battery control device for a vehicle equipped with a motor as a traveling power source, and more particularly to a battery control device that controls SOC (State Of Charge) of a battery that is a power source of the motor.

For example, in a hybrid vehicle, regenerative control of a motor during traveling on a downhill road, for example, recovers the vehicle's potential energy as regenerative power and charges the battery. Further, when traveling on an uphill road, the motor is controlled by powering with the discharge power from the battery to generate driving force, thereby reducing the burden on the engine and reducing fuel consumption. Excessive charging / discharging of the battery causes a decrease in durability. Therefore, in order to prevent this, regeneration control and power running control of the motor are executed so that the SOC of the battery is always kept within a predetermined control range.
However, for example, when traveling on a downhill road where the altitude difference is large, the regenerative control must be stopped when the SOC of the battery reaches the upper limit of the control range even though a large amount of regenerative power is obtained. Therefore, the subsequent potential energy of the vehicle is wasted as heat by the brake for adjusting the vehicle speed.

Therefore, for example, in the hybrid vehicle described in Patent Document 1, when it is predicted that a downhill road exists on the travel route of the own vehicle based on navigation information or the like, SOC expansion control that temporarily extends the SOC control range is performed. Running. The SOC expansion control is executed during traveling until reaching the downhill road and during traveling on the downhill road. While traveling to the downhill road, the SOC control range is expanded, and the motor is heavily used to lower the SOC to near the lower limit of the control range. Driving the motor reduces the burden on the engine, contributing to improved fuel efficiency. The battery power consumption at this time is recovered by regenerative control while traveling on a subsequent downhill road, and the SOC of the battery increases to the upper limit of the control range after expansion by charging the regenerative power. The electric power charged in this way is used for driving the motor in the subsequent travel, and contributes to improvement in fuel consumption.
On the other hand, while the SOC expansion control is advantageous in terms of fuel efficiency, it can be a factor for promoting the deterioration of the battery. For this reason, in the technology of Patent Document 1, from the viewpoint of battery protection, when the SOC extension control is repeated a predetermined number of times, thereafter, the execution of the SOC extension control is prohibited and the SOC is controlled within the normal SOC control range. .

JP 2005-160269 A

  Although the technique of Patent Document 1 can prevent battery deterioration due to the SOC expansion control, since the SOC expansion control is not executed after the limit number of times is reached, advantages such as fuel efficiency cannot be obtained. Since the progress of battery deterioration is greatly affected not only by the period of use but also by the usage environment, it is difficult to accurately set the limit number, and it is inevitably prohibited to perform the SOC expansion control at an appropriate timing. I can't. Therefore, it is necessary to secure a sufficient margin for preventing the deterioration of the battery, and the SOC expansion control may be prohibited earlier than necessary.

  The present invention has been made to solve such problems, and the purpose of the present invention is to charge more regenerative power to the battery by appropriately executing the SOC expansion control. An object of the present invention is to provide a battery control device for a vehicle that can prohibit SOC expansion control at an appropriate timing reflecting the deterioration state of the battery, and can make maximum use of the battery capacity for improving fuel efficiency.

  In order to achieve the above object, a battery control device for a vehicle according to the present invention includes a power running control of a power source for traveling and a battery power charging / discharging while maintaining a charge rate of the battery within a preset control range. While performing regenerative control, the control range of the charge rate is expanded by the charge rate expansion control means when the vehicle is in a predetermined traveling state set in advance, and the charge rate of the battery is controlled based on the expanded control range In the battery control device for a vehicle that executes the charge rate expansion control, the charge rate expansion control means holds the control range after expansion in a substantially constant range as an absolute amount regardless of the deterioration of the battery, and a ratio to the total capacity of the battery As described above, the control range after expansion is limited based on an upper limit allowable value and a lower limit allowable value set in advance.

  The charge rate expansion control is executed when the vehicle is in a specific traveling state, the control range of the battery charge rate is expanded, and the control range after the expansion is approximately constant as an absolute amount regardless of the deterioration of the battery. Retained. Then, such an extended control range is limited based on an upper limit allowable value and a lower limit allowable value set as a ratio to the total battery capacity. These allowable values are indicators that can accurately determine the suitability of the charge rate control range from the viewpoint of battery deterioration, so limit the control range for charge rate expansion control at an appropriate timing that reflects the battery deterioration state. it can. As a result, it is possible to continue to extend the control range of the charging rate to the battery degradation limit.

As another aspect, after the upper limit of the control range after the expansion reaches the upper limit allowable value, the control range after the expansion is limited after the lower limit of the control range after the expansion reaches the lower limit allowable value, and then the control before the expansion is performed. After the upper limit of the range reaches the upper limit allowable value and the lower limit of the control range before expansion reaches the lower limit allowable value, the charging rate is set so that execution of the charging rate expansion control is prohibited and the control range before expansion is limited. It is desirable to constitute an extended control means.
The control range of the charge rate expansion control can be limited at an appropriate timing that reflects the deterioration state of the battery, and the execution of the charge rate expansion control can be prohibited at an appropriate timing that also reflects the deterioration state.

As another aspect, the apparatus includes a deterioration index estimating means for estimating a deterioration index that correlates with the total capacity of the battery, and extends the control range of the charging rate before expansion based on a predetermined expansion width to expand to correspond to a battery when new. Expands the control range after expansion to compensate for the total capacity of the battery when it is new, based on the battery degradation index estimated by the degradation index estimation means. It is desirable to configure the charging rate expansion control means so that the subsequent control range is maintained in an almost constant width as an absolute amount.
Based on the deterioration index that correlates with the total capacity of the battery, the expanded control range is expanded to compensate for the total capacity of the battery when it is new. Therefore, regardless of the deterioration of the battery, the expanded control range can be held in an almost constant range as an absolute amount, and the expanded control range can inevitably be limited based on the upper limit allowable value and the lower limit allowable value.

  According to the present invention, it is possible to charge the battery with more regenerative power by appropriately executing the SOC expansion control, and prohibit the execution of the SOC expansion control at an appropriate timing reflecting the deterioration state of the battery. Therefore, the battery capacity at that time can be utilized to the maximum for improving fuel efficiency.

1 is an overall configuration diagram showing a hybrid truck on which a battery control device of an embodiment is mounted. It is a flowchart which shows the SOC control mode switching routine which vehicle ECU performs. It is a flowchart which shows the normal SOC range setting routine which vehicle ECU performs. It is a time chart which shows the correction condition of a normal SOC control range. It is a time chart which shows the correction condition of the SOC control range after expansion. It is a flowchart which shows the extended SOC range setting routine which vehicle ECU performs.

Hereinafter, an embodiment in which the present invention is embodied in a battery controller for a hybrid truck will be described.
FIG. 1 is an overall configuration diagram showing a hybrid truck on which the battery control device of this embodiment is mounted.
The hybrid truck 1 is configured as a so-called parallel hybrid vehicle, and may be referred to as a vehicle in the following description. A vehicle 1 is equipped with a diesel engine (hereinafter referred to as an engine) 2 as a driving power source and a motor 3 that can also operate as a generator such as a permanent magnet synchronous motor. A clutch 4 is connected to the output shaft of the engine 2, and an input side of the automatic transmission 5 is connected to the clutch 4 via a rotating shaft of the motor 3. A differential device 7 is connected to the output side of the automatic transmission 5 via a propeller shaft 6, and left and right drive wheels 9 are connected to the differential device 7 via a drive shaft 8.

  The automatic transmission 5 automates the connection / disconnection operation of the clutch 4 and the switching operation of the shift stage based on a general manual transmission. In this embodiment, the automatic transmission 5 has a shift stage of 12 forward speeds and 1 reverse speed. ing. Of course, the configuration of the transmission 5 is not limited to this, and can be arbitrarily changed. For example, the transmission 5 may be embodied as a manual transmission, or a so-called dual clutch automatic transmission having two power transmission systems. It may be embodied as a machine.

  A battery 11 is connected to the motor 3 via an inverter 10. The DC power stored in the battery 11 is converted into AC power by the inverter 10 and supplied to the motor 3 (power running control), and the driving force generated by the motor 3 is transmitted to the drive wheels 9 after being shifted by the automatic transmission 5. The vehicle 1 is made to travel. For example, when the vehicle 1 decelerates or travels on a downhill road, the motor 3 operates as a generator by reverse driving from the drive wheel 9 side (regenerative control). The negative driving force generated by the motor 3 is transmitted to the driving wheel 9 side as a braking force, and the AC power generated by the motor 3 is converted into DC power by the inverter 10 and charged to the battery 11.

  The driving force generated by the motor 3 is transmitted to the driving wheel 9 regardless of the state of connection / disconnection of the clutch 4, and the driving force generated by the engine 2 is driven only when the clutch 4 is connected. 9 side. Therefore, when the clutch 4 is disengaged, the positive or negative driving force generated by the motor 3 as described above is transmitted to the driving wheel 9 side, and the vehicle 1 travels. When the clutch 4 is connected, the driving force of the engine 2 and the motor 3 is transmitted to the driving wheel 9 side, or only the driving force of the engine 2 is transmitted to the driving wheel side, so that the vehicle 1 travels.

The vehicle ECU 13 is a control circuit for integrated control of the entire vehicle. For this purpose, the vehicle ECU 13 includes an accelerator sensor 15 that detects the operation amount θacc of the accelerator pedal 14, a brake switch 17 that detects the depression operation of the brake pedal 16, a vehicle speed sensor 18 that detects the speed V of the vehicle 1, and the rotation of the engine 2. Various sensors and switches such as an engine rotation speed sensor 19 for detecting the speed Ne and a motor rotation speed sensor 20 for detecting the rotation speed Nt of the motor 3 are connected.
The vehicle ECU 13 is connected with an actuator (not shown) for connecting / disconnecting the clutch 4 and an actuator for shifting the automatic transmission 5, and an engine ECU 22 for engine control and an inverter ECU 23 for inverter control. And a battery ECU 24 for managing the battery 11 are connected.

  The vehicle ECU 13 calculates a required torque necessary for the vehicle 1 to travel based on the accelerator operation amount θacc by the driver, and selects the travel mode of the vehicle 1 based on the required torque, the SOC of the battery 11, and the like. In this embodiment, an E / G mode that uses only the driving force of the engine 2, an EV mode that uses only the driving force of the motor 3, and an HEV mode that uses both the driving force of the engine 2 and the motor 3 are set as the traveling mode. The vehicle ECU 13 selects one of the travel modes.

  The vehicle ECU 13 converts the required torque into a torque command value to be output by the engine 2 or the motor 3 based on the selected travel mode. For example, in the HEV mode, the required torque is distributed to the engine 2 side and the motor 3 side, and torque command values for the engine 2 and the motor 3 are calculated based on the gear position at that time. In the E / G mode, the required torque is converted into a torque command value for the engine 2 based on the gear position, and in the EV mode, the required torque is converted into a torque command value for the motor 3 based on the gear speed.

  Then, the vehicle ECU 13 disconnects the clutch 4 in the EV mode and connects the clutch 4 in the E / G mode and HEV mode in order to execute the selected travel mode, and then sends a torque command value to the engine ECU 22 and the inverter ECU 23. Output as appropriate. Further, during traveling of the vehicle 1, the vehicle ECU 13 calculates a target gear position from a shift map (not shown) based on the accelerator operation amount θacc, the vehicle speed V, and the like, and the actuator 4 connects and disconnects the clutch 4 to achieve this target gear position. Executes operation and gear change operation.

  On the other hand, the engine ECU 22 executes injection amount control and injection timing control so as to achieve the travel mode and torque command value input from the vehicle ECU 13. For example, in the E / G mode and the HEV mode, the driving force is generated in the engine 2 with respect to the positive torque command value, and the engine brake is generated with respect to the negative torque command value. Further, in the EV mode, the engine 2 is stopped and held by stopping the fuel injection or is set in an idle operation state.

  Further, the inverter ECU 23 controls the motor 3 via the inverter 10 so as to achieve the travel mode and the torque command value input from the vehicle ECU 13. For example, in the EV mode or HEV mode, the motor 3 is controlled by powering the positive torque command value to generate a positive driving force, and the motor 3 is regeneratively controlled to the negative torque command value. Generate negative driving force. In the E / G mode, the driving force of the motor 3 is controlled to zero.

Further, the battery ECU 24 detects the temperature of the battery 11, the voltage of the battery 11, the current flowing between the inverter 10 and the battery 11, etc., and sequentially calculates the SOC of the battery 11 from these detection results and outputs it to the vehicle ECU 13. To do. In parallel with this, the battery ECU 24 sequentially estimates a deterioration index (SOH: State of Health) of the battery 11, and outputs this to the vehicle ECU 13 as information related to the deterioration of the battery 11 (degradation index estimating means).
The deterioration index correlates with the total capacity of the battery 11 that gradually decreases as the battery 11 is used, and a known method can be applied to the estimation. For example, as described in Japanese Patent Application Laid-Open Nos. 2000-131404 and 2010-78530, a deterioration index may be estimated from the capacity when the battery is fully charged and the internal resistance of the battery (deterioration index estimation). means).

On the other hand, excessive charging / discharging of the battery 11 causes a decrease in durability. Therefore, in order to avoid such a situation, the vehicle ECU 13 always keeps the SOC of the battery 11 within a predetermined control range. Regenerative control and power running control are executed.
Further, similar to the technique of Patent Document 1, when the vehicle ECU 13 predicts that a downhill road is present on the travel route of the host vehicle, the vehicle ECU 13 executes SOC expansion control for temporarily extending the SOC control range (charging rate expansion). Control means). From the viewpoint of battery protection, it is necessary to prohibit the execution of the SOC expansion control when the total capacity is reduced to some extent due to the deterioration of the battery 11, but in the technique of Patent Document 1 using the limit number as an index, an appropriate timing is required. However, there is a problem that the execution of the SOC extension control cannot be prohibited. Therefore, in the present embodiment, execution of the SOC expansion control is prohibited based on another index, and the process executed by the vehicle ECU 13 will be described below.

First, in order to execute the SOC expansion control prior to traveling on the downhill road, it is necessary to predict the downhill road on the traveling route of the own vehicle. For this purpose, the vehicle ECU 13 has a navigation device 31 as shown in FIG. And the communication apparatus 32 is connected.
The navigation device 31 stores map information in its own storage area in advance, and sequentially receives GPS information via an antenna while the vehicle 1 is traveling to identify the position of the vehicle on the map. Further, the communication device 32 performs road-to-vehicle communication with a roadside communication system of a data center installed on the roadside, and performs vehicle-to-vehicle communication with other vehicles traveling around. Examples of communication targets include map information that the vehicle does not have, road information (road curves and gradients, etc.), traffic information (congestion information, accident information, construction information, etc.), or local information (tourist spot information, etc.) The communication device 32 acquires such information from the roadside communication system and other vehicles, or conversely supplies the information to other vehicles.

  The vehicle ECU 13 acquires these various types of information from the navigation device 31 and the communication device 32, and predicts road conditions on the traveling route of the vehicle. For example, when a downhill road exists on the travel route of the own vehicle, information such as the distance from the vehicle position to the downhill road, the length of the downhill road, and the road surface gradient is acquired.

The vehicle ECU 13 executes the SOC control mode switching routine shown in FIG. 2 at predetermined control intervals while the vehicle 1 is traveling. The routine includes a normal setting mode for setting a normal SOC control range to be applied in normal time (when other than SOC extended control), and an extended setting mode for setting a post-expansion SOC control range to be applied in SOC extended control. For switching between and.
First, road information is acquired from the navigation device 31 and the communication device 32 in step S2. In the subsequent step S4, it is determined whether or not there is a downhill road ahead on the travel route of the vehicle based on the acquired road information. When the determination is No (No), the process proceeds to step S6, and after selecting the normal setting mode, the routine is temporarily ended.

  Further, when the determination in step S4 is Yes (positive), the process proceeds to step S8, where it is determined whether or not the vehicle has approached a predetermined distance with respect to the downhill road ahead. Use to select the normal setting mode. If the determination in step S8 is Yes, it is determined in step S10 whether or not the downhill road has ended. If yes, the normal setting mode is selected in step S6. When the determination in step S10 is No, the process proceeds to step S12, and after the extended setting mode is selected, the routine is terminated.

Therefore, if there is a downhill road ahead on the traveling route of the vehicle, it is considered that the execution condition of the SOC expansion control is satisfied, and the traveling on the downhill road is terminated when the vehicle approaches the downhill road to the set distance. The extension setting mode is selected during the period up to the point of time. During this period, the SOC expansion control is executed based on the post-expansion SOC control range set in the expansion setting mode, and fuel efficiency is improved.
In addition, restrictions on the driving system side of the vehicle 1 can be added to the execution conditions of the SOC expansion control. For example, in order to prevent the operation of the motor 3 or the battery 11 at a high temperature or a low temperature, a restriction regarding a temperature condition may be added. Further, in order to prevent abnormal heat generation of the battery 11 due to excessive charging / discharging, a restriction on charging / discharging current may be added.

When the normal setting mode is selected in step S6 of FIG. 2, the vehicle ECU 13 starts a normal SOC range setting routine shown in FIG. As described above, the normal SOC control range is set in the routine as described above, but in the present embodiment, the SOC control range is corrected according to the deterioration index of the battery 11 and is different from the technique of Patent Document 1.
First, in step S22, the normal SOC control range RNGbase stored in its own storage area is read. The SOC control range RNGbase is set in advance as an optimum value (for example, 40 to 60%) corresponding to the total capacity of the battery 11 when new. In subsequent step S24, a deterioration index is acquired as information related to the deterioration of the battery 11 from the battery ECU 24, and it is determined based on the deterioration index whether or not the current battery 11 is deteriorated in step S26.

If the battery 11 has not yet deteriorated, the determination of No is made in step S26 and the routine is terminated. In this case, the SOC control range RNGbase read in step S22 is directly applied to the SOC control of the battery 11, and the regenerative control and power running control of the motor 3 are executed so as to keep the SOC of the battery 11 within the control range RNGbase. Is done.
If the determination in step S26 is Yes because the battery 11 has deteriorated, the process proceeds to step S28, and the SOC control range RNGbase read in step S22 is corrected in the expansion direction based on the deterioration index of the battery 11. The routine ends.
More specifically, in step S26, the upper limit of the SOC control range RNGbase is calculated so as to calculate a decrease amount of the total capacity from the new battery 11 based on the deterioration index of the battery 11 at that time and to compensate the total capacity at the new time. Is corrected in the increasing direction, and the lower limit is corrected in the decreasing direction. As a result, the normal SOC control range RNGbase (corresponding to when new) is gradually expanded according to the deterioration of the battery 11, and the SOC of the battery 11 is controlled based on the expanded SOC control range RNGbase.

FIG. 4 is a time chart showing the correction status of the normal SOC control range RNGbase, and the total capacity gradually decreases as the battery 11 is used. For example, in the technique of Patent Document 1, the SOC control range RNGbase is maintained at a predetermined ratio with respect to the total capacity of the battery 11. For this reason, as shown by a broken line in FIG. 4, the usable capacity gradually decreases as the total capacity of the battery 11 decreases.
In the present embodiment, as indicated by a solid line in FIG. 4, the SOC control range RNGbase is gradually corrected in the expansion direction in accordance with a decrease in the total capacity. For this reason, the usable capacity of the battery 11 does not decrease, and is kept substantially constant over a predetermined period. If the SOC control range RNGbase is excessively expanded, the deterioration of the battery 11 becomes significant. Therefore, the expansion of the SOC control range RNGbase is stopped at a point A when a predetermined period has elapsed, and thereafter the usable capacity of the battery 11 is increased. Begins to decline.

In the lowermost part of FIG. 4, the SOC control range RNGbase is expressed as a ratio to the total capacity. However, when the SOC control range RNGbase is an absolute battery capacity (Kwh), it is expressed as shown in FIG.
When the SOC control range RNGbase is not enlarged and corrected, the SOC control range RNGbase is set as a predetermined ratio to the total capacity of the battery 11 at that time. Therefore, as indicated by a broken line in FIG. 5, the SOC control range RNGbase as an absolute amount is gradually reduced as the battery 11 deteriorates (decrease in total capacity). In the present embodiment, the ratio of the SOC control range RNGbase to the total capacity of the battery 11 is gradually expanded so as to keep the usable battery capacity substantially constant. Therefore, as indicated by a solid line in FIG. 5, the SOC control range RNGbase as an absolute amount is kept substantially constant regardless of the deterioration of the battery 11.

On the other hand, when the extended SOC mode is selected in step S12 of FIG. 2, the vehicle ECU 13 starts an extended SOC range setting routine shown in FIG. As described above, in this routine, the post-expansion SOC control range RNGext applied to the SOC expansion control is set. In this embodiment, the post-expansion SOC control range RNGext is corrected according to the deterioration index of the battery 11, This is different from the technique of Patent Document 1.
First, in step S32, the expanded SOC control range RNGext stored in its own storage area is read. The expanded SOC control range RNGext is based on the normal SOC control range RNGbase corresponding to the battery 11 when it is new, and the upper and lower limits are expanded by a predetermined expansion width (for example, 10%). It is.

  The subsequent processing after step S34 is the same as that after step S24 in FIG. First, in step S34, a deterioration index of the battery 11 is acquired. Based on the deterioration index, it is determined in step S36 whether or not the battery 11 is deteriorated. If No, the routine is terminated. When the determination in step S36 is Yes, the process proceeds to step S38, the expanded SOC control range RNGext read in step S32 is corrected in the expansion direction based on the deterioration index of the battery 11, and the routine is terminated. In this way, the SOC control range RNGext after the expansion is set, and the SOC expansion control is executed based on the control range RNGext to control the SOC of the battery 11.

Therefore, for example, when the SOC control range RNGbase is set as a predetermined ratio to the total capacity of the battery 11 as in the technique of Patent Document 1, as shown by the broken line in FIG. Like the control range RNGbase, the expanded SOC control range RNGext is gradually reduced as the battery 11 deteriorates.
On the other hand, in this embodiment, the ratio of the SOC control range RNGext after expansion to the total capacity of the battery 11 is gradually expanded. Therefore, the control range RNGext of the SOC after expansion as an absolute amount is related to the deterioration of the battery 11. It is kept almost constant. Specifically, both the normal control range RNGbase that is the base of the extended SOC control range RNGext and the expansion width Ext for extending the control range RNGbase are maintained at a substantially constant width regardless of the deterioration of the battery 11. As a result, the SOC control range RNGext after the expansion is also kept substantially constant. For this reason, during the execution of the SOC expansion control, the SOC can be greatly varied by making the maximum use of the battery capacity, which can sufficiently contribute to the improvement of fuel consumption.

Thus, in the SOC extension control, the SOC of the battery 11 is controlled based on the SOC control range RNGext after the extension. However, in this control, since the SOC control range RNGext after expansion as an absolute amount is kept substantially constant, the SOC after expansion with respect to the total capacity as the total capacity of the battery 11 decreases. The ratio occupied by the control range RNGext gradually increases. As the battery 11 deteriorates accordingly, it is necessary to prohibit the expansion of the SOC control range RNGext at a certain time.
From this point of view, in this embodiment, the upper limit allowable value LMTup and the lower limit allowable value LMTlo are set in advance as a predetermined ratio with respect to the total capacity of the battery 11 (for example, 20 to 80%), and the SOC control range is within these allowable values. RNGext is restricted.

In order to accurately determine whether or not the setting of the SOC control range RNGext is appropriate from the viewpoint of deterioration of the battery 11, the ratio of the SOC control range RNGext to the current total capacity of the battery 11 is used as an index. Is most desirable. This is because the SOC of the battery 11 varies within the control range RNGext, and the wider the control range RNGext, the closer the SOC approaches the upper limit or lower limit of the total capacity, and the deterioration of the battery 11 becomes more significant.
Then, according to the SOC expansion control of the present embodiment in which the SOC control range RNGext as an absolute amount is maintained at a substantially constant width, the ratio of the SOC control range RNGext to the total capacity gradually increases as the battery 11 deteriorates. Therefore, the upper and lower limits of the SOC control range RNGext reach the respective allowable values LMTup and LMTlo at any point in time, and thereafter, it can be determined that the current SOC control range RNGext is inappropriate.

As indicated by the solid line in FIG. 5, the total capacity gradually decreases from the time when the battery 11 is new (point a in FIG. 5), and accordingly, the upper and lower limits of the SOC control range RNGext reach the respective allowable values LMTup and LMTlo. Then, the SOC control range RNGext is limited to the upper limit allowable value LMTup and the lower limit allowable value LMTlo (charge rate expansion control means). Therefore, although the SOC expansion control is continued, the upper and lower expansion limits are gradually reduced.
Note that the upper limit and the lower limit of the SOC control range RNGext may reach the permissible values LMTup and LMTlo. In this case, the restriction based on the allowable values LMTup and LMTlo may be started in order from the arrival side.

  When the upper limit and lower limit extension width Ext is reduced to 0, substantial SOC extension control is prohibited (point c in FIG. 5), and the normal SOC control range RNGbase is applied. Thereafter, the total capacity of the battery 11 decreases, and the ratio of the SOC control range RNGbase to the total capacity continues to increase. For this reason, the normal SOC control range RNGbase is gradually reduced by the restriction based on the upper limit allowable value LMTup and the lower limit allowable value LMTlo (charging rate expansion control means).

  Here, the period until the new battery 11 reaches the deterioration limit due to use and is discarded is, for example, a considerably long period of about 100,000 km in terms of the travel distance of the vehicle 1. On the other hand, the period during which the SOC extension control is executed based on the prediction of the downhill road is a very short period of about several kilometers, for example. For this reason, during the whole use period of the battery 11, the execution period of many SOC expansion control for every downhill road is dotted. Then, when the condition for executing the SOC extension control is established by prediction of the downhill road, the SOC control range RNGext set at that time is applied to the SOC control of the battery 11.

Specifically, when the condition for executing the SOC expansion control is satisfied during a period (points a and b in FIG. 5) from when the battery 11 is new to when the upper limit allowable value LMTup and the lower limit allowable value LMTlo are started. The SOC extension control is executed based on the extended SOC control range RNGext obtained by adding the extension width Ext to the normal SOC control range RNGbase.
Further, when the execution condition for the SOC expansion control is satisfied during the period (points b to c in FIG. 5) from when the restriction by the upper limit allowable value LMTup and the lower limit allowable value LMTlo is started until the expansion width Ext is reduced to zero. Then, the SOC expansion control is executed based on the SOC control range RNGext after the expansion that is gradually reduced. Further, if the execution condition of the SOC expansion control is satisfied during the period after the expansion width is reduced to 0 (after point c in FIG. 5), the normal SOC expansion control is prohibited and gradually reduced. The SOC of the battery 11 is controlled based on the control range RNGbase.

  As described above, according to the battery control device of the vehicle 1 of the present embodiment, the SOC control range RNGbase is extended by the extension width Ext when the execution condition of the SOC extension control is established based on the prediction of the downhill road. The expanded SOC control range RNGext is maintained as an absolute amount within a substantially constant range regardless of the deterioration of the battery 11. Then, the SOC control range RNGext after such expansion is limited based on the upper limit allowable value LMTup and the lower limit allowable value LMTlo set as a ratio to the total capacity of the battery 11. Since these allowable values LMTup and LMTlo are indices that can accurately determine the suitability of the SOC control range RNGext from the viewpoint of the deterioration of the battery 11, the SOC expansion control is performed at an appropriate timing reflecting the deterioration state of the battery 11. The control range RNGext can be limited (points b to c in FIG. 5). Further, it is possible to prohibit the execution of the SOC expansion control at an appropriate timing reflecting the deterioration state (after point c in FIG. 5).

Therefore, it is possible to continue to extend the SOC control range RNGext to the deterioration limit of the battery 11 during the execution of the SOC expansion control, so that the total capacity of the battery 11 can be utilized to the maximum for improving the fuel consumption.
Further, if the total capacity changes with the specification change of the battery 11, the technique of Patent Document 1 requires a conformance test for setting a new limit number. On the other hand, according to the present embodiment, the timing for limiting the control range RNGext of the SOC expansion control and the timing for prohibiting the execution of the SOC expansion control are automatically changed corresponding to the change in the total capacity of the battery 11. For example, when the total capacity decreases due to the specification change of the battery 11, the control range RNGext of the SOC extension control is limited earlier, and the execution of the SOC extension control is prohibited earlier. Therefore, even if the specification of the battery 11 is changed, the SOC control range RNGext can always be extended to the deterioration limit of the battery 11 without performing a conformance test.

  This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment, the present invention is applied to a hybrid truck equipped with the engine 2 and the motor 3 as a driving power source, but the present invention is not limited to this. For example, the present invention may be applied to an electric vehicle equipped with only the motor 3 as a driving power source, or may be applied to a bus or a passenger car.

  Further, in the above embodiment, when a downhill road is predicted on the traveling route of the host vehicle, the SOC expansion control is performed during traveling until reaching the downhill road and during traveling on the downhill road (a specific traveling state). Yes, but not limited to this. For example, the SOC expansion control may be executed only during traveling on a downhill road. Further, the charging power to the battery 11 may be increased by executing the SOC expansion control while the vehicle 1 is decelerating (specific traveling state).

1 truck (vehicle)
3 Motor 11 Battery 13 Vehicle ECU (charging rate expansion control means)
24 battery ECU (degradation index estimating means)

Claims (3)

While maintaining the charging rate of the battery within a preset control range, power running control and regenerative control of the driving power source is executed in accordance with charging / discharging of the battery, and the vehicle is set in a specific running state. In the vehicle battery control device for executing the charge rate expansion control for extending the control range of the charge rate by the charge rate expansion control means when the vehicle is in the state and controlling the charge rate of the battery based on the control range after the expansion,
The charging rate expansion control means holds the control range after expansion in a substantially constant range as an absolute amount regardless of the deterioration of the battery, and sets an upper limit allowable value and a lower limit set in advance as a ratio to the total capacity of the battery. A battery control apparatus for a vehicle, wherein the control range after the expansion is limited based on an allowable value.   The charging rate expansion control means limits the control range after the expansion after the upper limit of the control range after the expansion reaches the upper limit allowable value, and the lower limit of the control range after the expansion reaches the lower limit allowable value. When the upper limit of the control range before the expansion reaches the upper limit allowable value and the lower limit of the control range before the expansion reaches the lower limit allowable value, the execution of the charge rate expansion control is prohibited and the control range before the expansion is The battery control device for a vehicle according to claim 1, wherein: A deterioration index estimating means for estimating a deterioration index correlated with the total capacity of the battery,
The charging rate expansion control means expands the control range of the charging rate before expansion based on a predetermined expansion width to be an expanded control range corresponding to the new battery, and is estimated by the deterioration index estimation means. By expanding the control range after expansion to compensate for the total capacity of the new battery based on the deterioration index of the battery, the control range after expansion is almost constant as an absolute amount regardless of the deterioration of the battery. The vehicle battery control device according to claim 1, wherein the vehicle battery control device is held in the vehicle.

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