Charge and discharge controller

Abstract

To provide a charge and discharge controller making it possible to effectively charge a battery with regenerative electric power in an electric vehicle which is externally chargeable, and contribute to a reduction in driving cost due to mitigation of an external charge quantity.SOLUTION: A charge and discharge controller (charge ECU 10) includes an altitude acquisition unit 10a that acquires an altitude of a travel position in the event that an electric vehicle 12 having a battery pack 18 (battery) which is externally chargeable moves from a first point P1 to a second point P2, an electricity quantity calculation unit 10b that calculates an electricity quantity of the battery pack 18 to be used to move from the first point P1 to the second point P2 exhibiting a high altitude, a regenerative quantity calculation unit 10c that designates charge and discharge efficiencies (α and β) of the battery pack 18 on the basis of the electricity quantity, and acquires a regenerative electricity quantity capable of regenerating in the event that the electric vehicle moves from the second point P2 to the first point P1, and a charge quantity control unit 10d that, when the electric vehicle is externally charged at the second point P2, designates a charge upper limit value for external charge by subtracting the regenerative electricity quantity from the electricity quantity with which the battery pack 18 is chargeable.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a charge / discharge control device. [Background technology]

[0002] Conventionally, electric vehicles (electric cars, plug-in hybrid cars, etc.) that can be charged externally use a motor generator as a motor to consume battery power and run on uphill roads. On downhill roads, the motor generator is used as a generator to generate regenerative power and charge the battery while running. When the motor generator is used as a generator, it can also function as a regenerative brake. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-152926 A [Patent Document 2] JP 2016-84061 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, for example, if the battery is fully charged by external charging to make up for the power consumed after climbing a slope, regeneration may not be possible when descending a slope, and regenerative braking may not be available, which may lead to a deterioration in drivability. In this case, mechanical braking must be used, and potential energy at high altitudes is wasted as heat energy due to the use of mechanical braking, resulting in a problem of energy waste.

[0005] An object of the present invention is to provide a charge / discharge control device for an electric vehicle equipped with an externally chargeable battery, which enables regenerative electric power to be effectively charged into the battery, and contributes to reducing operating costs by reducing the amount of external charging. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the charge / discharge control device of the present invention includes an altitude acquisition unit that acquires the altitude of a traveling position when an electric vehicle equipped with an externally chargeable battery moves from a first point to a second point; an electrical quantity calculation unit that calculates the amount of electricity of the battery to be used when moving from the first point to the second point at a higher altitude; a regeneration amount calculation unit that sets the charge / discharge efficiency of the battery based on the amount of electricity and acquires the amount of regenerative power that can be regenerated when moving from the second point to the first point; and a charge amount control unit that, when performing external charging at the second point, subtracts the amount of regenerative power from the amount of power that can be charged to the battery to set an upper charge limit value for external charging.

[0007] According to this configuration, for example, when externally charging at the second point after climbing a slope, a charging upper limit is set for the external charging amount in anticipation of the amount of power regenerated and charged when descending a slope, so that a margin area for regenerative charging can be left in the battery when traveling downhill. As a result, it is possible to effectively charge the battery with regenerative power, and it is possible to contribute to reducing operating costs by reducing the amount of external charging. In addition, regenerative braking is used when descending a slope, which also contributes to improving drivability.

[0008] Furthermore, the charge / discharge efficiency of the charge / discharge control device of the present invention may be acquired, for example, as a constant value or a variable value based on at least one of the temperature of the battery, the state of charge of the battery, and the power when charging or discharging the battery.

[0009] According to this configuration, for example, if the charge / discharge efficiency is a constant value, the amount of regenerative power can be easily obtained. Also, if the charge / discharge efficiency is a variable value, a more accurate amount of regenerative power can be obtained.

[0010] In addition, the charge amount control unit of the charge / discharge control device of the present invention may be capable of displaying either a virtual display that displays a state in which the regenerative power amount is subtracted from the actual fully charged state of the battery as an apparent full charge, or an actual display that displays the actual fully charged state of the battery as a full charge, for example, when setting the charge upper limit value when moving to the first point which is at a lower altitude than the second point.

[0011] According to this configuration, for example, in the case of a virtual display, a full charge display is performed even if a charging upper limit value is set. As a result, a full charge display is performed during external charging, so that for users who do not fully understand the functions of the charge / discharge control device, it is possible to make it appear as if the battery is fully charged even when the charging amount is limited, making it less likely that the user will feel uncomfortable when charging. On the other hand, for users who fully understand the functions of the charge / discharge control device, a real display can be performed, making it easier for them to properly recognize the actual charging state, i.e., the vehicle state. Effect of the Invention

[0012] According to the present invention, a charge / discharge control device can be provided in an electric vehicle equipped with an externally chargeable battery, which can effectively charge the battery with regenerative electric power and contribute to reducing operating costs by reducing the amount of external charging. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an exemplary schematic diagram showing the configuration of an electric vehicle equipped with a charge / discharge control device according to an embodiment. [Diagram 2] FIG. 2 is an exemplary schematic block diagram showing a configuration of a charging ECU as a charge / discharge control device according to the embodiment. [Diagram 3] FIG. 3 is an exemplary schematic explanatory diagram showing, as a time chart, changes in altitude, power, corrected power amount, charged state (SOC), and displayed full charge value during control by the charge / discharge control device according to the embodiment. [Figure 4]FIG. 4 is an exemplary flowchart showing a control procedure of the charge / discharge control device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] FIG. 1 is an exemplary schematic diagram showing the configuration of an electrically powered vehicle 12 (electric automobile) equipped with a charge / discharge control device (a charge ECU (Electronic Control Unit) 10) according to this embodiment.

[0016] The electric vehicle 12 includes a charging ECU 10 that functions as a charge / discharge control device, a motor unit 16 connected to drive wheels 14D, a battery pack 18, and a vehicle control ECU 20 that controls the entire electric vehicle 12. In Fig. 1, the charging ECU 10, a DC / DC converter 22, and a battery remaining gauge 24 are connected to the vehicle control ECU 20. An auxiliary battery 26 is also connected to the DC / DC converter 22. An atmospheric pressure sensor 28 is also connected to the charging ECU 10.

[0017] The electric vehicle 12 charges a battery pack 18 with power supplied from an external charger BS, and drives a motor generator 16a included in a motor unit 16 as a motor using the power stored in the battery pack 18 to control the rotation of drive wheels 14D and travel. Note that while Fig. 1 shows a front-wheel drive vehicle in which the motor unit 16 is connected to the front wheels 14F and the front wheels 14F are drive wheels 14D, the motor unit 16 may be connected to the rear wheels 14R and the rear wheels 14R may be drive wheels 14D, making the vehicle a rear-wheel drive vehicle. Also, the motor unit 16 may be connected to both the front wheels 14F and the rear wheels 14R to make a four-wheel drive vehicle.

[0018] The motor unit 16 is a power unit called an "e-axle" that integrates devices such as a motor generator 16a (MG), an inverter 16b, and a transaxle 16c (power transmission mechanism). The motor generator 16a can function as a motor and can be a drive source for the electric vehicle 12. For example, a type using a permanent magnet can be used as the motor generator 16a. The inverter 16b converts a direct current supplied from a battery pack 18 (battery) into an alternating current (three-phase alternating current) and drives the motor generator 16a that functions as a motor. The inverter 16b also controls the motor output in response to an accelerator operation of the electric vehicle 12. When the motor generator 16a functions as a generator, the inverter 16b converts a regenerated alternating current into a direct current and charges the battery pack 18 via the vehicle control ECU 20. The transaxle 16c includes a transmission that appropriately changes the speed of the motor generator 16a that functions as a motor, a differential gear that distributes driving force to drive shafts connected to the left and right drive wheels 14D, etc. Note that the motor unit 16 is an example, and the motor generator 16a, inverter 16b, trunk axle 16c, etc. may be arranged separately, and the layout can be changed as appropriate.

[0019] The battery pack 18 is, for example, a battery pack made up of a plurality of secondary batteries, and is capable of charging and discharging. The secondary batteries are, for example, lithium ion batteries.

[0020] The vehicle control ECU 20 controls the entire electric vehicle 12. For example, when a charging plug 12A provided on a part of the body of the electric vehicle 12 and a charging plug BSA of an external charger BS are connected by a dedicated charging cable (not shown), the vehicle control ECU 20 functions as a charger and performs charging processing for the battery pack 18. When the electric vehicle 12 is coasting (when the accelerator is off) or traveling downhill, the motor generator 16a functions as a generator and performs a charging processing for charging the battery pack 18 with regenerative power during regenerative operation.

[0021] The external charger BS is a charging station provided at a predetermined location. The external charger BS can be installed at a location where the electric vehicle 12 can be parked, such as a parking lot or a gas station, and can appropriately charge the electric vehicle 12.

[0022] Furthermore, the vehicle control ECU 20 converts the power supplied from the external charger BS, the power regenerated by the motor generator 16a, or the power supplied from the battery pack 18 to a predetermined voltage via the DC / DC converter 22, and performs charging control so that the charge amount of the auxiliary battery 26 becomes a set charge amount. The auxiliary battery 26 is used to supply power to various electronic devices mounted on the vehicle (for example, an audio system, a navigation system, various lamps, etc.).

[0023] Furthermore, the vehicle control ECU 20 controls the display of a battery remaining capacity gauge 24 in accordance with the control of the charging ECU 10. The battery remaining capacity gauge 24 mainly displays the amount of charge in the battery pack 18. The display of the battery remaining capacity gauge 24 will be described in detail later.

[0024] Next, a detailed description will be given of the charging ECU 10 (charge / discharge control device). The charging ECU 10 mainly controls charging of the battery pack 18.

[0025] FIG. 2 is an exemplary schematic block diagram showing the configuration of the charging ECU 10. The charging ECU 10 includes, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a solid state drive (SSD, flash memory). The CPU of the charging ECU 10 reads out a charging control program installed and stored in a non-volatile storage unit such as a ROM or SSD, and executes various modules for executing charging control of the battery pack 18 according to the charging control program. The CPU of the charging ECU 10 realizes, for example, an altitude acquisition unit 10a, an electric amount calculation unit 10b, a regeneration amount calculation unit 10c, a charging amount control unit 10d, and the like as various modules. In another embodiment, the altitude acquisition unit 10a, the electric amount calculation unit 10b, the regeneration amount calculation unit 10c, the charging amount control unit 10d, and the like may be configured by hardware. Furthermore, the altitude acquisition unit 10a, the electricity amount calculation unit 10b, the regeneration amount calculation unit 10c, and the charge amount control unit 10d may be configured with their functions integrated or separated.

[0026] The altitude acquisition unit 10a acquires the altitude of the traveling position when the electric vehicle 12 moves from a first point to a second point, for example, based on the air pressure (absolute pressure) detected by the atmospheric pressure sensor 28. In this case, the altitude acquisition unit 10a acquires the relative altitude, for example, based on the differential pressure between the air pressure at the first point and the air pressure at the destination point (including the second point).

[0027] The electricity amount calculation unit 10b calculates the amount of electricity in the battery pack 18 used when the electric vehicle 12 moves from a first point to a point at a high altitude (for example, a second point) via the vehicle control ECU 20. That is, the electricity amount calculation unit 10b sequentially calculates the amount of power consumed by the motor generator 16a when climbing an uphill road.

[0028] The regeneration amount calculation unit 10c sets the charge / discharge efficiency of the battery pack 18 based on the amount of electricity (power consumption) acquired by the electricity amount calculation unit 10b, and acquires the amount of regenerative power that can be regenerated when moving from the second point to the first point. For example, the amount of power regenerated (generated) when traveling downhill from the second point to the first point is smaller than the amount of power consumed (discharged) when traveling uphill from the first point (e.g., the foot of the hill) to the second point (e.g., the summit). In other words, the amount of regeneration is, for example, about 50% of the amount of discharge. In this case, the amount of regeneration expected when traveling downhill is the value obtained by multiplying the amount of discharge (amount of consumption) consumed by traveling uphill by a reduction coefficient (a value of 1 or less) as the charge / discharge efficiency. The charge / discharge coefficient at this time is "α". Note that even when traveling uphill from the first point to the second point, there may be a temporary downhill run, in which case regeneration is performed. However, when going downhill on the same route, the part that was downhill when going uphill becomes uphill, so in this case, twice the amount of consumption (discharge) is required as the amount of regeneration. In other words, the amount of regeneration (power generation) generated by going downhill when going uphill is multiplied by a reduction coefficient (a value of 1 or more) as the charge / discharge efficiency. The charge / discharge coefficient in this case is "β". Therefore, by sequentially adding the value obtained by multiplying the power consumption when going uphill by the charge / discharge efficiency α and the value obtained by multiplying the regenerative power when going uphill by the charge / discharge efficiency β, the amount of regenerative power that can be regenerated when moving from the second point to the first point can be obtained.

[0029] The charge / discharge efficiency can be determined by the performance of the motor generator 16a, the battery pack 18, the inverter 16b, etc. The charge / discharge efficiency may be a constant value determined in advance based on tests or the like for each configuration of the electric vehicle 12, or may be a variable value calculated each time based on at least one of the temperature of the battery pack 18, the state of charge, and the power during charging / discharging. When the charge / discharge efficiency is used as a constant value, the calculation process of the amount of regenerative power becomes easier, which contributes to reducing the processing load. On the other hand, when the charge / discharge efficiency is used as a variable value, the accuracy of the calculation value of the amount of regenerative power can be improved, making it possible to perform the charge / discharge process more appropriately.

[0030] When external charging is performed at the second point via the external charger BS, the charge amount control unit 10d subtracts the amount of regenerative power calculated by the regeneration amount calculation unit 10c from the amount of power that can be charged to the battery pack 18, and sets a charging upper limit value during external charging. That is, by reducing the amount of power to be charged to the battery pack 18 in anticipation of the amount of regenerative power regenerated during downhill driving, the regenerative power regenerated by the motor generator 16a during downhill driving can be charged to the battery pack 18. In this case, the battery pack 18 is fully charged when the vehicle reaches the first point by descending the slope. Furthermore, when charging is performed at the external charger BS at the second point, the battery pack 18 is not fully charged, which contributes to reducing charging costs. Furthermore, regeneration is always possible during downhill driving (during downward driving), so that regenerative braking can be used. As a result, the use of mechanical braking is reduced, and the potential energy is reduced from being wasted as thermal energy of the mechanical brake when descending from a high place. Furthermore, frequent use of regenerative braking contributes to improving drivability.

[0031] However, when the charging amount control unit 10d sets a charging upper limit value during external charging, the battery pack 18 does not reach full charge even if the external charging is performed sufficiently. In this case, the battery remaining amount meter 24 provided on the dashboard of the electric vehicle 12 does not indicate full charge either, which may cause the user to feel uncomfortable. Therefore, when the charging amount control unit 10d sets a charging upper limit value and performs charging before moving to a first point that is lower in altitude than the second point, the charging amount control unit 10d can perform a virtual display that displays a state in which the amount of regenerated power is subtracted from the actual full charge state of the battery pack 18 displayed on the battery remaining amount meter 24 as an apparent full charge. In other words, even if the battery pack 18 is actually charged to less than full charge at the second point, the subtracted charging state before the downhill regeneration is set to full charge, so that the user is not made to feel insufficient charge after charging at the external charger BS (it is possible to make it difficult to feel uncomfortable during charging).

[0032] Furthermore, when setting the upper charge limit value when moving to a first point that is lower in altitude than a second point, the charge amount control unit 10d can perform an actual display that displays the full charge of the battery pack 18 displayed by the battery remaining gauge 24 as the actual full charge. For example, the actual display makes it easier for a user who fully understands the functions of the charge / discharge control device (charging ECU 10) to properly recognize the actual charge state of the battery pack 18, that is, the state of the electric vehicle 12.

[0033] The charge amount control unit 10d may set the display of the battery remaining gauge 24 to either the virtual display or the real display as a default, or may selectively switch between either the virtual display or the real display. For example, the user may select either the virtual display or the real display by operating a switch. As a result, the battery remaining gauge 24 can be displayed according to the user's preference, which contributes to improved usability.

[0034] Fig. 3 is an exemplary and schematic explanatory diagram showing, as a time chart T, changes in altitude, power, corrected power amount, charged state (SOC), and displayed full charge value during control by the charge / discharge control device (charging ECU 10) configured as described above. Fig. 3 shows an example of moving from a first point P1 (e.g., the foot of the mountain) to a second point P2 (e.g., the summit) and then returning to the first point P1 again. The external charger BS is assumed to be installed at the first point P1, the second point P2, etc.

[0035] The time chart T1 shows a change in altitude of the road on which the electric vehicle 12 travels. In the time chart T1, an example is shown in which the electric vehicle starts traveling uphill from a first point P1, travels through an uphill section Pu, travels partially through a downhill section Pd, travels through the uphill section Pu again, and reaches a second point P2 which is the summit. After that, the electric vehicle follows the same route, starts traveling downhill from the second point P2, travels through the downhill section Pd, travels partially through the uphill section Pu, travels through the downhill section Pd again, and reaches the first point P1 which is the base of the road.

[0036] The time chart T2 shows the change in power during uphill travel and downhill travel. In the section corresponding to the uphill section Pu, the motor generator 16a is used as a motor to perform power running D, and the battery pack 18 is consumed (discharged). In the section corresponding to the downhill section Pd, the motor generator 16a is used as a generator to perform regeneration R, and the battery pack 18 is charged. However, when charging is performed by the external charger BS at the second point P2, the battery pack 18 is in a fully charged state during downhill travel. As a result, in the section M, the regenerated power cannot be charged into the battery pack 18, and is discarded as thermal energy by using the mechanical brake. Note that by temporarily traveling through the uphill section Pu during downhill travel, a section MS exists in which the regenerated power can be temporarily charged to compensate for the discharge that occurs.

[0037] The time chart T3 shows the amount of correction power to enable regenerative charging during downhill driving when charging is performed by the external charger BS at the second point P2. In the time chart T3, the dashed line C1 shows the power consumption by power running. The two-dot chain line C2 shows the regenerative charging power. The solid line C3 shows the correction power during external charging. In the correction power shown by the solid line C3, a value multiplied by a predetermined charging / discharging efficiency α is added as a subtraction value in the power consumption section shown by the dashed line C1. On the other hand, in the correction power shown by the solid line C3, a value multiplied by a predetermined charging / discharging efficiency β is subtracted as a subtraction value in the regenerative charging power section shown by the two-dot chain line C2. In the time chart T3, the arrow C1A shows the amount of power consumed during uphill driving, and the arrow C3A shows the amount of power that can be regenerated during downhill driving. The correction amount of power is reset during charging at the external charger BS.

[0038] Next, the time chart T4 shows the change in the state of charge (SOC) of the battery pack 18. In the time chart T4, the line S is an upper guard value indicating full charge. In the example shown in the time chart T4, the battery pack 18 is fully charged at the first point P1. Therefore, the SOC value SO1 decreases from the fully charged state during uphill travel (powered running and regeneration). When charging the battery pack 18 again at the second point P2, which is the top, as shown in the time chart T3, the charging upper limit value is set by subtracting the amount of regenerated power during downhill travel, which is calculated by taking into account the charge and discharge efficiency, from the amount of power consumed during uphill travel. In other words, charging is completed in a state where a margin is created for charging the amount of power regenerated during downhill travel. As a result, the SOC value SO2 after charging at the second point P2 remains below the upper guard value indicated by the line S during downhill travel (regenerated and powered running) from the second point P2 to the first point P1. Then, when the vehicle reaches the first point P1, it is fully charged at the upper guard value (line S). In other words, external charging is no longer necessary when the vehicle reaches the first point P1, which also contributes to reducing operating costs.

[0039] In this way, the charging upper limit value is set for the external charging amount in anticipation of the amount of power that will be regenerated and charged when descending the slope during external charging at the second point P2 after climbing the slope, so that a margin for regenerative charging can be left in the battery pack 18 when traveling downhill. As a result, it is possible to effectively charge the battery pack 18 with regenerative power, and it is possible to contribute to reducing operating costs by reducing the amount of external charging. In addition, regenerative braking can be used when descending the slope, which also contributes to improving drivability.

[0040] The time chart T5 shows the change in the displayed full charge value. When going uphill, the battery pack 18 is mainly discharged, and even if there is a downhill section, regeneration does not occur to the extent that charging is not possible. Therefore, when going uphill, the full charge state of the battery pack 18 is displayed as 100% in the actual display (line H1). On the other hand, when moving to the first point P1, which is lower in altitude than the second point P2, a charge upper limit value is set taking into account regeneration during downhill, so the state (line H2) obtained by subtracting the amount of regenerated power from the actual full charge state of the battery pack 18 is displayed as an apparent full charge, and the full charge state of the battery pack 18 is displayed as a virtual display (line H3). In other words, even if the battery pack 18 is actually charged to a level lower than full charge at the second point P2 (line H2), the subtracted charge state before the downhill regeneration is considered to be full charge, so the full charge state is displayed along the virtual display (line H3). Therefore, after charging in the external charger BS, the user is prevented from feeling that the battery is insufficiently charged (a sense of discomfort during charging is reduced). Note that a switching operation may be performed to display the actual fully charged state of the battery pack 18 as being fully charged.

[0041] Next, an example of a control procedure of the charge / discharge control device (the charge ECU 10) will be described with reference to the flowchart of FIG.

[0042] First, the altitude acquisition unit 10a calculates the altitude during external charging, for example, in an external charger BS located on flat ground, based on the detection result of the atmospheric pressure sensor 28. In this case, if a correction amount such as a charging upper limit value has been set, it is reset once (S100).

[0043] Next, the power consumption during discharging (power running) of the battery pack 18 while traveling on flat ground and the regenerative power during charging (regeneration) are calculated (S102). Then, it is determined whether or not a certain distance has been traveled (S104). If the certain distance has not been traveled (No in S104), the process returns to S102 and performs power calculation. If the certain distance has been traveled (Yes in S104), it is determined whether or not the vehicle has moved to a higher altitude than a certain altitude (whether or not the vehicle has climbed a slope) based on the results of the altitude acquisition unit 10a (S106). If the vehicle has moved to a higher altitude than a certain altitude (Yes in S106), a correction amount for calculating a charging upper limit value based on the slope is calculated (S108). That is, the power consumption during power running is multiplied by the charging / discharging efficiency α, and a value is sequentially subtracted and integrated to calculate the power that can be regenerated when descending a slope. If the vehicle has not moved to a higher altitude than a certain altitude (No in S106), the process of S108 is skipped.

[0044] Also, when the vehicle has traveled a certain distance (Yes in S104), it is determined whether the vehicle has moved to a lower altitude than a certain level (whether the vehicle has descended a slope) based on the results of the altitude acquisition unit 10a (S110). When the vehicle has moved to a lower altitude than a certain level (Yes in S110), a correction amount is calculated to calculate a charging upper limit value based on the slope being descended (S112). That is, the charging power during regeneration is multiplied by the charging / discharging efficiency β, and a value is sequentially added and integrated to calculate the power that can be regenerated when descending a slope. Note that when the vehicle has not moved to a lower altitude than a certain level (No in S110), the process of S112 is skipped.

[0045] Then, it is determined whether or not charging is to be performed using a charging facility (external charger BS) (S114). If charging is not to be performed, the process proceeds to S102, and the processes from S102 onwards are executed. If charging is to be performed using a charging facility (Yes in S114), charging is performed by subtracting the power added or subtracted by regeneration and power running (this can also be a percentage of the SOC value) from the full charge of the battery pack 18. In other words, charging is performed by setting an upper limit value for external charging. Then, when charging is completed, the correction amounts for the upper limit value and the like are reset, and this flow is temporarily terminated.

[0046] In this way, for example, when external charging is performed at the second point P2 after climbing a slope, a charging upper limit is set for the external charging amount in anticipation of the amount of power that will be regenerated and charged when descending a slope, and charging is then performed. As a result, a surplus area for regenerative charging can be secured in the battery pack 18 when traveling downhill, making it possible to effectively charge the battery pack 18 with regenerative power, and contributing to reducing driving costs by reducing the amount of external charging when using the external charger BS. In addition, regenerative braking is used when traveling downhill, which also contributes to improving drivability.

[0047] Also, for example, the altitude of the first point P1 and the power consumption up to the second point P2 may be recorded as absolute values ​​without being reset at the time of charging. Then, when the difference in altitude between the altitude at which charging is performed again at or near the second point P2 and the second point P2 at which charging was performed previously is equal to or less than a predetermined value, that is, when the vehicle has not descended sufficiently, the upper limit of charging at the time of recharging may be set based on the value of the first point P1 stored as an absolute value and the power consumption up to the second point P2. Then, processing for descending the slope to the first point P1 thereafter may be executed. In this case, even when recharging is performed after traveling at high altitude, a surplus area for regenerative charging can be left in the battery pack 18 during the subsequent descending slope, so that it is possible to effectively charge regenerative power, save the amount of external charging, and effectively use regenerative braking. The first point P1 and the value of the power consumption integration stored as absolute values ​​may be values ​​from the lowest altitude in the traveling history of the vehicle.

[0048] (Effects of this embodiment) As described above, the charge / discharge control device (charging ECU 10) according to this embodiment includes an altitude acquisition unit 10a that acquires the altitude of a traveling position when an electric vehicle 12 equipped with an externally chargeable battery pack 18 (battery) moves from a first point P1 to a second point P2, an electrical quantity calculation unit 10b that calculates the electrical quantity of the battery pack 18 used when moving from the first point P1 to a second point P2 having a higher altitude, a regeneration amount calculation unit 10c that sets the charge / discharge efficiency (α, β) of the battery pack 18 based on the electrical quantity and acquires the amount of regenerative power that can be regenerated when moving from the second point P2 to the first point P1, and a charge amount control unit 10d that, when performing external charging at the second point P2, subtracts the amount of regenerative power from the amount of power that can be charged to the battery pack 18 to set a charging upper limit value during external charging. In this way, the charging upper limit value is set for the external charging amount in anticipation of the amount of power that will be regenerated and charged when descending the slope during external charging at the second point P2 after climbing the slope, so that a margin for regenerative charging can be left in the battery pack 18 when traveling downhill. As a result, it is possible to effectively charge the battery pack 18 with the power that can be regenerated when traveling downhill, and this contributes to reducing operating costs by reducing the amount of external charging. In addition, regenerative braking can be used when traveling downhill, which also contributes to improving drivability.

[0049] Furthermore, the charge / discharge efficiency (α, β) of the charge / discharge control device (charging ECU 10) according to this embodiment may be acquired as, for example, a constant value or a variable value based on at least one of the temperature of the battery pack 18, the state of charge of the battery pack 18, and the power when charging / discharging the battery pack 18. In this way, if the charge / discharge efficiency is set to a constant value, the amount of regenerated power can be easily acquired. Furthermore, if the charge / discharge efficiency is set to a variable value, a more accurate amount of regenerated power can be easily acquired.

[0050] In addition, the charge amount control unit 10d of the charge / discharge control device (charging ECU 10) according to this embodiment may be capable of displaying either a virtual display that displays a state obtained by subtracting the amount of regenerative power from the actual fully charged state of the battery pack 18 as an apparent full charge, or a real display that displays the actual fully charged state of the battery pack 18 as a full charge, when, for example, a charge upper limit value is set when moving to a first point P1 that is lower in altitude than the second point P2. As a result, in the case of the virtual display, a full charge display is performed even if a charge upper limit value is set, so that a full charge display is performed during external charging. As a result, for users who do not fully understand the functions of the charge / discharge control device (charging ECU 10), it is possible to make it appear as if the battery is fully charged even when the charge amount is limited, making it less likely that the user will feel uncomfortable during charging. On the other hand, for users who fully understand the functions of the charge / discharge control device (charging ECU 10), it is possible to perform a real display, making it easier for them to properly recognize the actual charge state, that is, the vehicle state.

[0051] Even if the vehicle moves without changing altitude at the second point P2 (e.g., the summit) due to the setting of the charging upper limit, the possibility of long-distance travel is low, so even if the charging is limited, there is no problem of running out of power, and regeneration is possible when going downhill after that, and the same effect as described above can be obtained. In addition, even if the vehicle is charged again after traveling at high altitude and moves to flat ground (downhill) after traveling at high altitude, regeneration is possible when going downhill because there is a margin for regeneration, and the same effect as described above can be obtained. In addition, in the charging ECU 10 of this embodiment, when setting the charging upper limit, calculation is performed based on the power actually used when traveling, not on climbing information using map information or GPS information, so that accurate calculation can be easily performed, which contributes to reducing the processing load of the charging ECU 10 and making the system more compact.

[0052] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is presented as an example and is not intended to limit the scope of the present invention. This new embodiment can be embodied in various other forms. In addition, various omissions, substitutions, and modifications can be made without departing from the gist of the invention. In addition, this embodiment is included in the scope and gist of the invention, and is included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0053] 10 Charging ECU (Charge / Discharge Control Unit) 10a Altitude acquisition section 10b Electric quantity calculation section 10c Regeneration amount calculation section 10d Charge amount control section 12 Electric vehicles 16 Motor unit 16a Motor generator 16b Inverter 16c transaxle 18 Battery Pack 20 Vehicle control ECU 22 DC / DC converter 24 Battery Gauge 26 Auxiliary battery 28 Atmospheric pressure sensor BS external charger

Claims

1. an altitude acquisition unit that acquires an altitude of a traveling position when an electric vehicle equipped with an externally chargeable battery moves from a first point to a second point; an electric quantity calculation unit that calculates an electric quantity of the battery to be used when moving from the first point to the second point at a higher altitude; a regeneration amount calculation unit that sets a charge / discharge efficiency of the battery based on the amount of electricity and acquires an amount of regenerative power that can be regenerated when moving from the second point to the first point; a charge amount control unit that, when performing external charging at the second location, subtracts the amount of regenerative power from the amount of power that can be charged to the battery to set a charge upper limit value during external charging; A charge / discharge control device comprising:

2. 2 . The charge / discharge control device according to claim 1 , wherein the charge / discharge efficiency is acquired as a constant value or a variable value based on at least one of a temperature of the battery, a state of charge of the battery, and a power during charging / discharging of the battery.

3. 2. The charge / discharge control device according to claim 1, wherein, when setting the charge upper limit value when moving to the first point which is at a lower altitude than the second point, the charge amount control unit is capable of displaying either a virtual display which displays a state of the battery obtained by subtracting the amount of regenerative power from the actual fully charged state of the battery as an apparent full charge, or an actual display which displays the actual fully charged state of the battery as a full charge.

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