JP2013216257A - Charge/discharge control device of electric storage means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency in traveling in a CS mode by raising an SOC control center of an electric storage means while suppressing harmful influence on fuel economy.SOLUTION: In traveling of a hybrid vehicle in CS mode, an SOC control center is not raised like the conventional art, but the SOC control center is raised only when an amount of electric power supplied to an electric storage means exceeds a predetermined threshold.

Description

  The present invention relates to a charge / discharge control device for a power storage means. In particular, the present invention relates to a charge / discharge control device for power storage means mounted on a hybrid vehicle that can switch a traveling mode between a CD mode and a CS mode.

  The electric vehicle travels by using a driving force generated from a power unit (for example, a rotating electric machine or the like) equipped with power storage means (for example, a secondary battery or a capacitor) and driven by electric power stored in the power storage means. . Examples of such an electric vehicle include an electric vehicle (EV) and a hybrid vehicle (HV).

  In various electric vehicles (for example, EV, HV, etc.) equipped with power storage means as described above, charging / discharging of power storage means is controlled by controlling charging / discharging of power storage means for the purpose of suppressing capacity reduction of power storage means. The state value SOC (State Of Charge) is controlled so as to fall within a predetermined range to prevent overcharging and overdischarging of the power storage means.

  For example, in this technical field, in a hybrid vehicle capable of external charging, the accumulated elapsed time from the time when the previous external charging was performed is confirmed when the ignition-on command is given, and the accumulated elapsed time is determined in advance. A technique has been proposed in which the SOC control center of the power storage means is raised when the specified threshold value is exceeded, so that traveling in the HV mode is repeated in a state where the SOC is low and the capacity reduction of the power storage means proceeds. (For example, see Patent Document 1).

  In a travel mode in which travel is controlled so that the amount of charge (SOC) of the power storage device mounted on the hybrid vehicle is maintained within a predetermined control range, an SOC that defines the control range when an abnormality related to the power storage device occurs. By setting the value of the control center higher than the normal value of the SOC control center set near the SOC management lower limit value, and allowing charging / discharging of the power storage device, the abnormality that has occurred is immediately charged to the power storage device. When the level is such that it is not necessary to cut off the discharge, a technique has been proposed in which the power storage device is protected by preventing overdischarge, and the vehicle operation with the use of the power storage device is continued (for example, Patent Document 2). See).

  Furthermore, a CD mode that travels preferentially using the power of the power storage device and a CS mode that controls the SOC of the power storage device within a certain control range by internal charging using the engine output are selected according to the vehicle state. In the hybrid vehicle to be operated, when a transition is made from the CS mode to the CD mode due to the establishment of a predetermined condition, a forcible charging period of the power storage device is provided independently of the SOC management, thereby preventing overdischarge. A technique for increasing the dischargeable power of the power storage device immediately after the mode transition has been proposed (see, for example, Patent Document 3).

  As described above, in this technical field, by controlling charging / discharging of power storage means mounted on various electric vehicles (for example, EV, HV, etc.), the SOC of the power storage means is within a predetermined specific range. Various techniques have been proposed for suppressing the capacity reduction of the power storage means due to overdischarge. However, if the SOC control center is simply increased when traveling in the CS mode in HV as in the above prior art, or if the power storage device is forcibly charged at the transition from the CS mode to the CD mode, it is caused by overdischarge. For example, when a large amount of traveling power is required in traveling in the CS mode, the necessary power cannot be supplied by the rotating electrical machine and Therefore, there is a risk that the fuel consumption may deteriorate as a result.

  By the way, in such an electric vehicle, for example, the electric vehicle is mounted on the electric vehicle by electric power supplied from an external power source such as a commercial power source (for example, a source of relatively low voltage such as 100 V or 200 V) supplied to each home. A technology for charging the power storage means has already been developed. Hereinafter, a vehicle capable of charging power storage means (for example, a battery or the like) mounted on the vehicle with an external power source may be referred to as a “plug-in vehicle”.

  In a hybrid vehicle (HV), for example, a rotating electrical machine that normally functions as a power source is driven as a power generator by an engine or a regenerative brake mounted on the HV, and power storage means mounted on the HV is used. An HV that can be charged by an external power source as described above has also been developed. Such HV is also referred to as a plug-in hybrid vehicle (PHV).

  The plug-in hybrid vehicle (PHV) can charge the power storage means with electric power supplied from an external power source such as an electric power infrastructure, for example, so that it has extremely good fuel efficiency compared to the conventional hybrid vehicle (HV). Can be realized. In a conventional general PHV, a CD mode (in which a vehicle travels while consuming electric power stored in a power storage means without using an engine as a power source, basically using only a rotating electric machine as a power source, depending on the running state of the vehicle. "EV mode") is basically a CS mode ("HV") that runs while maintaining the remaining capacity (SOC) of electric power stored in the power storage means within a predetermined range using the engine and rotating electrical machine as power sources. It is possible to travel by switching between modes.

  In the plug-in hybrid vehicle (PHV), for example, traveling in the CD mode is performed unless necessary power is reserved in advance for the purpose of separately traveling in the CD mode (EV mode). Accordingly, when the SOC of the power storage means decreases to the SOC control center in the CS mode (HV mode) or in the vicinity thereof, it is common to change the traveling mode of the vehicle from the CD mode to the CS mode. . At this time, in the PHV, for the purpose of securing as long a travel distance and travel time as possible in the CD mode, the SOC control center serving as a threshold for transitioning the travel mode of the vehicle from the CD mode to the CS mode is set as low as possible. It is common to set.

  By the way, as is well known in the technical field, there are some secondary batteries in which the open circuit voltage (OCV) is stable with respect to the change in the state of charge (SOC), In some cases, the OCV also changes as the SOC changes. For example, in a nickel metal hydride rechargeable battery (NiMH) or the like, a relatively stable OCV can be maintained even if the SOC varies, as represented by the broken line shown in FIG. On the other hand, in a general power storage means (for example, a lithium ion battery) mounted on an electric vehicle, as represented by a solid line shown in FIG. 1, the OCV tends to decrease as the SOC decreases. Therefore, as described above, when the SOC control center is kept low in order to avoid the deterioration of fuel consumption during traveling in the CS mode in the HV, or the traveling mode from the CD mode in the PHV to the CS mode as described above. In the case where the SOC of the power storage means that is the threshold value when switching the battery is set low, the battery voltage also decreases as described above, so that a larger current value is required to supply the necessary power. It will be.

  On the other hand, for example, in power electronics (power electronics) such as a power control device that transfers power between the power storage means and the rotating electrical machine, for example, it is caused by a resistance component existing in a conductor or an element included in the electric circuit. It is known that resistance loss occurs, and the resistance loss increases as the current value increases. That is, when a power device such as a rotating electrical machine is driven by electric power supplied from the power storage means, the lower the SOC of the power storage means (the larger the current value), the greater the resistance loss, resulting in lower energy efficiency. .

  As described above, there is a need in the technical field for a technology that can improve the efficiency in traveling in the CS mode by raising the SOC control center of the power storage means while suppressing adverse effects on fuel consumption. .

JP 2008-201262 A International Publication No. 2010/100736 JP 2010-241396 A

  As described above, in this technical field, in the technical field, the efficiency in traveling in the CS mode can be improved by raising the SOC control center of the power storage means while suppressing adverse effects on fuel consumption. There is a demand for technology. The present invention has been made to meet such a demand. That is, the present invention provides a charge / discharge control device for a power storage unit that can improve the efficiency in traveling in the CS mode by raising the SOC control center of the power storage unit while suppressing adverse effects on fuel consumption. Is one purpose.

The above purpose is
A charge / discharge control device for power storage means mounted on a hybrid vehicle having an engine and a rotating electrical machine as a power source,
In the CS mode, which is a travel mode in which the engine and the rotating electrical machine are basically used as a power source and the vehicle is traveling while being controlled so as to bring the SOC of the power storage means closer to a predetermined SOC control center, the power storage means The SOC control center is raised only when the amount of power supplied to exceeds a predetermined threshold.
This is achieved by the charge / discharge control device for the power storage means.

  According to the present invention, there is provided a charge / discharge control device for a power storage means that can improve the efficiency in traveling in the CS mode by raising the SOC control center of the power storage means while suppressing adverse effects on fuel consumption. Can do.

It is a typical graph showing the relationship between the charge condition value (SOC) and open circuit voltage (OCV) in a secondary battery. It is a typical graph showing the control image of SOC performed in the charging / discharging control apparatus of the electrical storage means which concerns on a prior art. It is a typical graph showing the control image of SOC performed in the charging / discharging control apparatus of the electrical storage means which concerns on one embodiment of this invention.

  As described above, one object of the present invention is to charge the power storage means that can improve the efficiency in traveling in the CS mode by raising the SOC control center of the power storage means while suppressing adverse effects on fuel consumption. A discharge control apparatus is provided.

  As a result of diligent research to achieve the above object, the present inventor has not simply raised the SOC control center in the CS mode as in the above-described prior art when the hybrid vehicle is traveling in the CS mode. By raising the SOC control center only during the period when the SOC of the power storage means exceeds the SOC control center during traveling in, the efficiency in traveling in the CS mode can be improved while suppressing adverse effects on fuel consumption. The headline and the present invention have been conceived.

That is, the first embodiment of the present invention is:
A charge / discharge control device for power storage means mounted on a hybrid vehicle having an engine and a rotating electrical machine as a power source,
In the CS mode, which is a travel mode in which the engine and the rotating electrical machine are basically used as a power source and the vehicle is traveling while being controlled so as to bring the SOC of the power storage means closer to a predetermined SOC control center, the power storage means The SOC control center is raised only when the amount of power supplied to exceeds a predetermined threshold.
It is a charging / discharging control apparatus of an electrical storage means.

  As described above, the charge / discharge control device for the power storage means according to the present embodiment is a charge / discharge control device for the power storage means mounted on a hybrid vehicle (HV) mounted with the engine and the rotating electrical machine as a power source. More specifically, the charge / discharge control device for the power storage means according to this embodiment controls the state of charge (SOC) of the power storage means for supplying power to the rotating electrical machine mounted on the HV. As described above, in HV, for example, a rotating electrical machine that normally functions as a power source is driven as a power generator by an engine or regenerative brake mounted on HV, and the power storage means mounted on HV is charged. can do. In the present specification, such a charging mode may be hereinafter referred to as “internal charging”.

  In the charge / discharge control apparatus for the power storage means according to this embodiment, basically, the engine and the rotating electrical machine are used as power sources, and the SOC of the power storage means is brought close to a predetermined SOC control center. In the CS mode, which is a traveling mode in which the vehicle travels while being controlled, the SOC control center is raised only when the amount of power supplied to the power storage means exceeds a predetermined threshold. In other words, in the charge / discharge control apparatus for the power storage means according to this embodiment, in the CS mode, when the amount of power supplied to the power storage means does not exceed a predetermined threshold, the SOC control center is raised. I can't.

  Here, when the amount of electric power supplied to the power storage means exceeds a predetermined threshold, for example, the engine is operated for purposes other than supply of traveling power (for example, heating of the passenger compartment). For example, when traveling on a long downhill road, a large regenerative energy can be obtained by regenerative braking. Note that the threshold value set in advance for the amount of power supplied to the power storage means constitutes power electronics (power electronics) such as a power control device that exchanges power between the power storage means and the rotating electrical machine, for example. It can be set as appropriate based on the magnitude of the resistance loss caused by the resistance component existing in the lead wire or element included in the electric circuit.

  According to the charging / discharging control device for the power storage device according to the present embodiment, as described above, in the CS mode, when the amount of power supplied to the power storage device does not exceed a predetermined threshold, the SOC control center Cannot be raised. Therefore, as described above, for example, when a large traveling power is required in traveling in the CS mode, the necessary power cannot be supplied by the rotating electrical machine, and the output from the engine must be relied on. As a result, the possibility of deteriorating fuel consumption can be reduced. That is, in the charge / discharge control device for the power storage means according to this embodiment, the SOC control center is raised only when the amount of power supplied to the power storage means exceeds a predetermined threshold value, resulting in deterioration of fuel consumption. The SOC of the power storage means can be raised without any problems. As a result, the open circuit voltage (OCV) of the general power storage means (for example, lithium ion battery) mounted on the hybrid vehicle (HV) also increases, so the same power is output to the rotating electrical machine with a smaller current value. Can be made. As a result, for example, the resistance loss due to the resistance component existing in the conducting wire or element included in the electric circuit such as a power electronics is reduced, so that the energy efficiency is improved.

  The configuration of the engine and the rotating electrical machine mounted as a power source in the hybrid vehicle (HV) equipped with the charge / discharge control device for the power storage means according to the present embodiment is not particularly limited, and is mounted as the HV power source. It is possible to appropriately select from a wide variety of engines and rotating electrical machines that can be used. Further, the configuration of the power storage means for supplying the electric power for driving the rotating electric machine is not particularly limited. For example, a lithium ion battery or the like can be mounted on the HV as a power supply for the rotating electric machine. It is possible to appropriately select from various power storage means.

  Further, the charge / discharge control device for the power storage means controls the charge / discharge of the power storage means, so that the SOC, which is the charge state value of the power storage means, falls within a specific range in the same manner as the charge / discharge control device for a general power storage means. Therefore, it is possible to suppress a decrease in capacity of the power storage means due to overcharge or overdischarge of the power storage means. Specifically, the charge / discharge control device for the power storage means is, for example, a specific value within the allowable range of the SOC of the power storage means (for example, the upper limit value or lower limit value of the SOC of the power storage means, or an intermediate value thereof) Is set as the SOC control center, and when the SOC of the power storage means is larger than the SOC control center, a discharge request to the power storage means is made, and conversely, when the SOC of the power storage means is smaller than the SOC control center, a charge request to the power storage means is made. By doing so, it is possible to control so that the SOC of the power storage means approaches the SOC control center.

  Therefore, the charge / discharge control device for the power storage means according to the present embodiment includes, for example, an SOC acquisition means for acquiring the SOC that is the charge state value of the power storage means, and an SOC control center that is the control target value of the SOC of the power storage means. The SOC of the power storage means and the forced charging threshold are compared, and when the SOC is larger than the SOC control center, a discharge request is made to the power storage means, and the SOC is smaller than the SOC control center. Sometimes, it may be constituted by charge / discharge requesting means for making a charge request to the power storage means. Further, the SOC acquisition means may be calculated from, for example, a cumulative value of the charging current and discharge current of the power storage means and the electrode potential of the power storage means, or may be estimated using a battery model based on an electrochemical reaction equation. it can. However, the configuration of the charge / discharge control device for the power storage means according to the present embodiment is not limited to the above.

  Note that the charge / discharge control device for the power storage means according to the present embodiment includes, for example, a central processing unit (CPU) that executes various arithmetic processes, a storage device (for example, a ROM (Read-Only Memory), a RAM ( It can be mounted as an electronic control unit (ECU) including a random access memory (HDD), a hard disk drive (HDD), or the like.

  By the way, the traveling state of the vehicle and the operating state of the engine change from moment to moment due to various factors such as the operation of the accelerator and brake by the driver, the road surface state, and the like. As a result, the SOC of the power storage means mounted on the hybrid vehicle (HV) when traveling in the CS mode also changes from moment to moment. Accordingly, in the control executed in the charge / discharge control device for the power storage means according to the present embodiment to raise the SOC control center during the period when the SOC of the power storage means exceeds the SOC control center when traveling in the CS mode, for example, If the SOC control center is raised even when the SOC of the power storage means suddenly exceeds the SOC control center due to the above factors, the transition state of the actual SOC (hereinafter sometimes referred to as “real SOC”) When the SOC control center becomes excessive and, as described above, for example, when a large traveling power is required for traveling in the CS mode, the necessary power cannot be supplied by the rotating electrical machine, and the output from the engine is relied on. Inevitably, the fuel consumption may be deteriorated as a result.

Accordingly, the second embodiment of the present invention provides:
A charge / discharge control device for a power storage means according to the first embodiment of the present invention, comprising:
The length of the period in which the SOC of the power storage means exceeds the SOC control center, the difference between the SOC of the power storage means and the SOC control center in the period, and the SOC of the power storage means and the SOC control center in the period The SOC control center is raised only when at least one of the integral values of the difference between the two exceeds a threshold value set in advance for each.
It is a charging / discharging control apparatus of an electrical storage means.

  As described above, in the charge / discharge control device for the power storage means according to this embodiment, the length of the period in which the SOC of the power storage means exceeds the SOC control center, the SOC of the power storage means and the SOC in the period The SOC only when at least one of the difference from the control center and the integral value of the difference between the SOC of the power storage means and the SOC control center in the period exceeds a threshold value set in advance for each. The control center is raised. That is, in the charge / discharge control device for the power storage means according to this embodiment, when the period in which the SOC of the power storage means exceeds the SOC control center is longer than a predetermined threshold value, When the difference between the SOC and the SOC control center is larger than a predetermined threshold, or when the integral value of the difference between the SOC of the power storage means and the SOC control center during the period is larger than a predetermined threshold Only, the SOC control center is raised.

  As described above, according to the charging / discharging control device for the power storage device according to the present embodiment, for example, when the SOC of the power storage device suddenly exceeds the SOC control center due to some factor, the SOC control center is not raised. . As a result, as described above, the SOC control center becomes excessive with respect to the actual SOC transition state, and for example, when a large traveling power is required in traveling in the CS mode, the necessary power is supplied by the rotating electrical machine. Therefore, it is necessary to rely on the output from the engine, and as a result, the possibility of deteriorating fuel consumption is reduced.

  Note that the length of the period in which the SOC of the power storage means exceeds the SOC control center, the difference between the SOC of the power storage means and the SOC control center in the period, and the SOC and SOC of the power storage means in the period The threshold value set in advance for each integral value of the difference from the control center is appropriately set by, for example, a running test of a hybrid vehicle (HV) equipped with the charge / discharge control device for the power storage unit according to this embodiment. can do.

  By the way, a plug-in hybrid vehicle (PHV) in which a hybrid vehicle (HV) equipped with a charge / discharge control device for power storage means according to the present invention can execute external charging, which is charging of the power storage means by electric power supplied from an external power source. ), As described above, for example, the CS mode is accompanied by the driving in the CD mode, except for the case where necessary electric power is reserved in advance for the purpose of separately performing the driving in the CD mode. In general, when the SOC of the power storage means decreases to the SOC control center at or near the SOC control center, the traveling mode of the vehicle is changed from the CD mode to the CS mode.

  Also, when the travel mode of the plug-in hybrid vehicle (PHV) is transitioned from the CD mode to the CS mode, the CD mode is switched to the CS mode for the purpose of ensuring the longest possible travel distance and travel time in the CD mode. In general, the SOC control center serving as a threshold value for changing the driving mode of the vehicle is set as low as possible. As described above, when the traveling in the CS mode is executed at a low SOC, in the general power storage means (for example, a lithium ion battery) mounted on the electric vehicle, as described above, the OCV also decreases when the SOC decreases. Because it tends to decrease, it is necessary to pass a larger current through the rotating electrical machine to achieve the required traveling power, resulting in increased resistance loss, resulting in decreased energy efficiency when traveling in CS mode. There is a risk of doing.

  Accordingly, even in this case, as in the charge / discharge control device for the power storage means according to the various embodiments described above, the SOC control center is raised during the period when the SOC of the power storage means exceeds the SOC control center when traveling in the CS mode. Can be considered desirable. However, a plug-in hybrid vehicle (PHV) in which a hybrid vehicle (HV) equipped with a charge / discharge control device for power storage means according to the present invention can perform external charging, which is charging of the power storage means by electric power supplied from an external power source. ), As described above, after the PHV driving mode transitions from the CD mode to the CS mode, the trip is quickly terminated, the external charging is performed, the SOC of the power storage means is increased, and the driving on the next trip is performed. The mode may return to the CD mode. In the present specification, a trip refers to a cycle from when a power device (for example, an engine, a rotating electrical machine, etc.) of a vehicle is started to when the power device is stopped after traveling of the vehicle.

  When traveling in the CS mode is not continued for a long time with the SOC of the power storage means being low as described above, the adverse effect on the energy efficiency throughout the trip due to resistance loss during the traveling period in the CS mode. Is also small. Even if the SOC control center is raised, the engine is operated for purposes other than driving power supply (for example, heating of the passenger compartment, etc.) during the driving period in the short CS mode as described above. There is a low possibility that a large regenerative energy is obtained by a regenerative brake or a regenerative brake. Therefore, when the charging / discharging control device for power storage means according to the present invention is mounted on a plug-in hybrid vehicle (PHV) as described above, the SOC control center is raised until the traveling period in the CS mode continues to some extent. The need is low.

Therefore, the third embodiment of the present invention
A charge / discharge control device for a storage means according to any one of the first or second embodiments of the present invention,
The hybrid vehicle is a plug-in hybrid vehicle capable of executing external charging, which is charging of the power storage means with electric power supplied from an external power source,
The SOC control center is raised only when at least one of the CS mode cumulative duration and cumulative mileage in a trip of the hybrid vehicle exceeds a preset threshold for each.
It is a charging / discharging control apparatus of an electrical storage means.

  As described above, in the charging / discharging control device for the power storage device according to the present embodiment, the hybrid vehicle (HV) can execute external charging, which is charging of the power storage device with electric power supplied from an external power source. It is an in-hybrid vehicle (PHV). Here, the external power source is provided in, for example, a commercial power source (for example, a relatively low voltage source such as 100 V or 200 V) supplied to each household, a charging facility such as a so-called “charging station”, or the like. Refers to a power source for charging.

  In a plug-in hybrid vehicle (PHV), power storage means mounted on the PHV can be charged with the electric power supplied from the external power source as described above. Therefore, as described above, until the traveling period in the CS mode continues to some extent, it is not necessary to raise the SOC control center. Therefore, the charge / discharge control device for the power storage means according to this embodiment is a power storage means in PHV. It can be said that this is a charge / discharge control device suitable for the charge / discharge control.

  In the charge / discharge control device for the power storage means according to the present embodiment, the cumulative duration and cumulative travel distance of the CS mode in the hybrid vehicle (HV) trip are one or more times excluding the period when the power unit is stopped. In the trip, the sum of the durations of the CS mode and the sum of the travel distances that are continuously present without interposing the driving in the CD mode or external charging are respectively indicated. In addition, the threshold value set in advance for each is, for example, a conductive wire included in an electric circuit that constitutes power electronics (power electronics) such as a power control device that transfers power between the power storage means and the rotating electrical machine. It can be set as appropriate based on the magnitude of the resistance loss caused by the resistance component present in the element.

  By the way, when the trip of the hybrid vehicle (HV) equipped with the charge / discharge control device for the power storage means according to the present invention is completed, the SOC control raised by the charge / discharge control device for the power storage means according to the present invention as described above. When the center is returned to the original value (reset), the SOC control center is maintained low until the amount of power supplied to the power storage means in the next trip exceeds a predetermined threshold value. For example, as described above, the resistance loss in the power control device that transfers power between the power storage means and the rotating electrical machine increases, and the energy efficiency decreases. Therefore, even if the trip in which the SOC control center is raised as described above is finished and the next trip is started, the SOC control center raised by the charge / discharge control device for the power storage means according to the present invention is maintained. Is desirable.

  However, for example, by the operation of a driver of a hybrid vehicle (HV) equipped with the charge / discharge control device for the power storage means according to the present invention, the rotating electrical machine is basically used as a power source without using the engine, and the power storage means is used. When the HV travel mode is switched to the CD mode, which is a travel mode that travels while consuming the stored power, the SOC of the power storage means decreases with the travel in the CD mode. If the SOC control center pulled up by the charge / discharge control device for the power storage means according to the present invention is maintained, the SOC control center becomes excessive with respect to the transition state of the actual SOC. For example, a large traveling power is required in traveling in the CS mode. The required power cannot be supplied by the rotating electrical machine, and the output from the engine must be relied upon, resulting in fuel efficiency. It is undesirably a fear of causing deterioration. Therefore, in such a case, as described above, it is desirable to reset the SOC control center raised by the charge / discharge control device for the power storage means according to the present invention to return it to the normal value.

  Further, when external charging is performed in a plug-in hybrid vehicle (PHV) equipped with the charge / discharge control device for power storage means according to the present invention, the next trip is generally started in the CD mode. is there. Therefore, if the SOC control center pulled up by the charge / discharge control device for the power storage means according to the present invention is maintained as described above, the power supply is supplied to the power storage means when the CS mode is changed for the first time after the external charging is performed. Regardless of whether or not the amount of electric power to be exceeded exceeds a predetermined threshold value, a high SOC control center is applied from the beginning. As a result, as described above, for example, when a large traveling power is required in traveling in the CS mode, the necessary power cannot be supplied by the rotating electrical machine, and the output from the engine must be relied upon. As a result, there is a possibility that the fuel consumption is deteriorated. Therefore, even in such a case, it is desirable to reset the SOC control center pulled up by the charge / discharge control device for the power storage means according to the present invention to return to the normal value as described above.

Therefore, the fourth embodiment of the present invention is
A charge / discharge control device for a storage means according to any one of the first or second embodiments of the present invention,
The raised SOC control center is maintained in the next trip,
When traveling in the CD mode, which is a traveling mode in which the rotating electric machine is basically used without using the engine as a power source and the electric power stored in the power storage means is consumed, is executed, The raised SOC control center is reset,
It is a charging / discharging control apparatus of an electrical storage means.

In addition, the fifth embodiment of the present invention provides:
A charge / discharge control device for a power storage means according to the third embodiment of the present invention, comprising:
The raised SOC control center is maintained in the next trip,
When traveling in the CD mode, which is a traveling mode in which the rotating electric machine is basically used without using the engine as a power source and the electric power stored in the power storage means is consumed, or external charging is performed The raised SOC control center is reset.
It is a charging / discharging control apparatus of an electrical storage means.

  As described above, according to the charging / discharging control device for a power storage device according to the present invention including the above-described embodiments, the SOC control center of the power storage device is raised while suppressing adverse effects on fuel consumption. In addition, it is possible to provide a charge / discharge control device for power storage means that can improve the efficiency in traveling in the CS mode.

  Several embodiments of the present invention will be described below with reference to the accompanying drawings. However, the following description is for illustrative purposes only, and the scope of the present invention should not be construed as being limited to the following description.

1. First, the SOC control in the charge / discharge control device for the power storage means according to the prior art will be described with reference to FIG. FIG. 2 is a schematic graph showing a control image of the SOC executed in the charge / discharge control device for the power storage means according to the prior art as described above. In the graph shown in FIG. 2, the horizontal axis and the vertical axis indicate time and SOC of the power storage means, respectively. The solid line represents the transition of the SOC of the power storage means, and the dotted line represents the SOC control center. In the example shown in FIG. 2, at the time t, the traveling mode of the vehicle is changed from the CD mode to the CS mode.

  As shown in FIG. 2, in the CD mode before time t, the vehicle is basically driven only by the rotating electric machine as a power source and without using the engine as a power source, while consuming the electric power stored in the power storage means. With the passage of time (with increasing travel distance), the SOC of the power storage means decreases. On the other hand, in the CS mode after time t, the engine and the rotating electrical machine are basically used as the power source, and the vehicle travels while controlling so that the SOC of the power storage means is close to a predetermined SOC control center. The SOC of the means fluctuates in the vicinity of the SOC control center.

  In the SOC control executed in the charge / discharge control device for the power storage means according to the prior art, the SOC control center is maintained constant regardless of the transition of the SOC of the power storage means in the CS mode. Specifically, as represented by the hatched portion in the graph shown in FIG. 2, the SOC executed in the charge / discharge control device for the power storage means according to the prior art even when there is a period during which large regenerative energy is obtained. In the control, the SOC control center is kept constant. Further, as described above, the SOC control center is a threshold value for transitioning the vehicle travel mode from the CD mode to the CS mode, so that the travel distance and travel time in the CD mode are as long as possible. The SOC control center is set as low as possible. Therefore, in the SOC control executed in the charge / discharge control device for the power storage means according to the prior art, as shown in FIG. 2, the SOC of the power storage means changes in a low state during traveling in the CS mode.

  As described above, in general power storage means (for example, a lithium ion battery) mounted on an electric vehicle, when the SOC decreases, the OCV tends to decrease. When the SOC of the power storage means changes in a low state, a larger current needs to flow through the rotating electrical machine to achieve the required traveling power, resulting in an increase in resistance loss. In the SOC control executed by the charge / discharge control device, the energy efficiency in traveling in the CS mode may be reduced.

  However, if the SOC control center indicated by the dotted line in FIG. 2 is simply set high, the timing at which the vehicle travel mode transitions from the CD mode to the CS mode will be earlier than the time t, and the vehicle will travel in the CD mode. Distance and running time will be shortened. In addition, as described above, even when traveling in the CS mode, the SOC control center becomes excessive with respect to the actual SOC transition state of the power storage means. For example, when a large traveling power is required, the necessary power is rotated. It cannot be supplied by an electric machine and must rely on the output from the engine, resulting in a deterioration in fuel consumption.

2. SOC Control in Charge / Discharge Control Device for Power Storage Unit According to One Embodiment of the Present Invention Next, the SOC control in the charge / discharge control device for the power storage unit according to one embodiment of the present invention will be described with reference to FIG. To do. FIG. 3 is a schematic graph showing a control image of the SOC executed in the charge / discharge control device of the power storage means according to one embodiment of the present invention as described above. Similar to the graph shown in FIG. 2, also in the graph shown in FIG. 3, the horizontal axis and the vertical axis indicate the time and the SOC of the power storage means, respectively. The solid line represents the transition of the SOC of the power storage means, and the dotted line represents the SOC control center. Also in the example shown in FIG. 3, at the time t, the traveling mode of the vehicle is changed from the CD mode to the CS mode.

  In the example shown in FIG. 3 as well, as in the example shown in FIG. 2, in the CD mode before time t, only the rotating electrical machine is basically used as the power source and the engine is not stored as the power source but is stored in the power storage means. Since the vehicle travels while consuming electric power, the SOC of the power storage means decreases with the passage of time (with an increase in travel distance). On the other hand, in the CS mode after time t, the engine and the rotating electrical machine are basically used as the power source, and the vehicle travels while controlling so that the SOC of the power storage means is close to a predetermined SOC control center. The SOC of the means fluctuates in the vicinity of the SOC control center.

  However, the SOC control executed in the charge / discharge control device for the power storage means according to one embodiment of the present invention shown in FIG. 3 is executed in the charge / discharge control device for the power storage means according to the prior art shown in FIG. Unlike the SOC control, the SOC control center is raised when the amount of power supplied to the power storage means exceeds a predetermined threshold. Specifically, in the SOC control executed in the charging / discharging control device for the power storage means according to one embodiment of the present invention, a large regenerative energy is obtained as represented by the hatched portion in the graph shown in FIG. If the specified period exists, the SOC control center is raised.

  As described above, in the SOC control executed in the charge / discharge control device for the power storage means according to one embodiment of the present invention shown in FIG. 3, the vehicle travel mode is changed from the CD mode to the CS mode (at time t). The SOC control center is increased when it is possible to sufficiently ensure the amount of electric power supplied to the power storage means during traveling in the CS mode without increasing the SOC control center that is a threshold value to be performed. As a result, in the SOC control executed in the charge / discharge control device for the power storage means according to one embodiment of the present invention shown in FIG. 3, the travel distance and travel time in the CD mode are ensured as long as possible, and the power storage means It can be avoided that the SOC control center becomes excessive with respect to the actual SOC transition state, resulting in deterioration of fuel consumption.

  In addition, in the SOC control executed in the charge / discharge control device for the power storage means according to one embodiment of the present invention shown in FIG. 3, as described above, the electric power supplied to the power storage means during traveling in the CS mode. The SOC control center is increased when a sufficient amount can be secured. As a result, as described above, it is possible to avoid a decrease in OCV even in a general power storage means (for example, a lithium ion battery) mounted on an electric vehicle that has a tendency to decrease in OCV as SOC decreases. Therefore, a large current can be passed through the rotating electrical machine in order to achieve the required traveling power, and the risk of reducing energy efficiency in traveling in the CS mode due to resistance loss in the charge / discharge control device can be reduced.

  Although several embodiments having specific configurations have been described above for the purpose of illustrating the present invention, the scope of the present invention is not limited to these exemplary embodiments, and patents Needless to say, modifications can be made as appropriate within the scope of the claims and the description of the specification.

Claims (5)

A charge / discharge control device for power storage means mounted on a hybrid vehicle having an engine and a rotating electrical machine as a power source,
In the CS mode, which is a travel mode in which the engine and the rotating electrical machine are basically used as a power source and the vehicle is traveling while being controlled so as to bring the SOC of the power storage means closer to a predetermined SOC control center, the power storage means The SOC control center is raised only when the amount of power supplied to exceeds a predetermined threshold.
Charge / discharge control device for power storage means. A charge / discharge control device for a power storage means according to claim 1,
The length of the period in which the SOC of the power storage means exceeds the SOC control center, the difference between the SOC of the power storage means and the SOC control center in the period, and the SOC of the power storage means and the SOC control center in the period The SOC control center is raised only when at least one of the integral values of the difference between the two exceeds a threshold value set in advance for each.
Charge / discharge control device for power storage means. The charge / discharge control device for a power storage unit according to any one of claims 1 and 2,
The hybrid vehicle is a plug-in hybrid vehicle capable of executing external charging, which is charging of the power storage means with electric power supplied from an external power source,
The SOC control center is raised only when at least one of the CS mode cumulative duration and cumulative mileage in a trip of the hybrid vehicle exceeds a preset threshold for each.
Charge / discharge control device for power storage means. The charge / discharge control device for a power storage unit according to any one of claims 1 and 2,
The raised SOC control center is maintained in the next trip,
When traveling in the CD mode, which is a traveling mode in which the rotating electric machine is basically used without using the engine as a power source and the electric power stored in the power storage means is consumed, is executed, The raised SOC control center is reset,
Charge / discharge control device for power storage means. A charge / discharge control device for a power storage means according to claim 3,
The raised SOC control center is maintained in the next trip,
When traveling in the CD mode, which is a traveling mode in which the rotating electric machine is basically used without using the engine as a power source and the electric power stored in the power storage means is consumed, or external charging is performed The raised SOC control center is reset.
Charge / discharge control device for power storage means.

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