On-board power storage system

Abstract

The present invention discloses a vehicle-mounted power storage system. During external charging, in which a power storage device is charged by a charging device using power from an external power source, a command current for external charging is sent to the charging device. In this case, during external charging, after the start of charging, the response speed of the charging device is estimated based on the change in the current of the power storage device accompanying the change in the command current, and after the response speed of the charging device is estimated, the command current is set in consideration of the response speed of the charging device.

Description

Technical Field

[0001] The present invention relates to a vehicle-mounted power storage system. Background Art

[0002] In the past, as such a technology, a charging system has been proposed, which includes: a charging control unit that calculates the chargeable power based on the difference between the charging target voltage lower than the charging prohibition voltage and the voltage of the power storage device, and calculates the command current based on the chargeable power; and a charging device that charges the power storage device based on the command from the charging control unit (for example, refer to Japanese Patent No. 6308301). In this charging system, the charging control unit calculates the command current in a manner that maintains the voltage of the power storage device at the charging target voltage after the voltage of the power storage device reaches the charging target voltage. In addition, the charging control unit stops charging the power storage device when the voltage of the power storage device exists in an allowable voltage region determined within a voltage range higher than the charging target voltage and lower than the charging prohibition voltage for more than a predetermined time, and when the voltage of the power storage device reaches the charging prohibition voltage. Summary of the invention

[0003] In the above-mentioned charging system, when the response speed of the charging device is low, when the command current is reduced, the followability of the current reduction of the power storage device relative to the command current is likely to be reduced. When this followability is reduced, the voltage of the power storage device remains in the allowable voltage region or reaches the charging prohibition voltage (generating an overvoltage), and the possibility of stopping the charging of the power storage device midway becomes high.

[0004] A main object of the vehicle-mounted power storage system of the present invention is to enable more appropriate charging of a power storage device even when the response speed of the charging device is low.

[0005] In order to achieve the above-mentioned main object, the vehicle-mounted power storage system of the present invention adopts the following means.

[0006] The vehicle-mounted power storage system of the present invention is mounted on a vehicle. The vehicle-mounted power storage system includes a power storage device and a control device. The control device is configured to send a command current for external charging to the charging device when the power storage device is charged by the charging device using power from an external power source. The control device is configured to estimate the response speed of the charging device based on the change in the current of the power storage device accompanying the change in the command current after the start of the external charging, and after estimating the response speed of the charging device, set the command current in consideration of the response speed of the charging device.

[0007] In the vehicle-mounted power storage system of the present invention, during external charging in which the power storage device is charged by the charging device using the power from the external power source, the command current for external charging is sent to the charging device. In this case, during external charging, after the charging starts, the response speed of the charging device is estimated based on the change in the current of the power storage device accompanying the change in the command current. After the response speed of the charging device is estimated, the command current is set in consideration of the response speed of the charging device. Thus, even in the case where the response speed of the charging device is relatively low, it is possible to suppress the follow-up of the decrease in the current of the power storage device relative to the command current when the command current is decreased, and it is possible to suppress the occurrence of undesirable situations such as overvoltage and overcharging of the power storage device. As a result, the charging of the power storage device can be performed more appropriately. Here, the charging device can be configured either outside the vehicle or inside the vehicle (the vehicle is equipped). In the former case, compared with the latter case, the response speed of the charging device is likely to be lowered due to the communication delay between the control device and the charging device, so the significance of the present invention is greater.

[0008] In the vehicle-mounted power storage system of the present invention, the control device may also set the command current in such a manner that the change speed of the command current becomes less than the response speed of the charging device when the command current is reduced after the response speed of the charging device during the external charging is estimated. If so, it is possible to prevent the change speed of the command current from becoming greater than the response speed of the charging device when the command current is reduced after the response speed of the charging device is estimated. Thus, even when the response speed of the charging device is relatively low, it is possible to prevent the generation of undesirable conditions such as overvoltage and overcharging of the power storage device when the command current is reduced.

[0009] In this case, the control device may set the command current according to the basic command current based on the power storage ratio of the power storage device during the external charging, and when the control device reduces the basic command current after estimating the response speed of the charging device during the external charging, when the absolute value of the change speed of the basic command current temporarily exceeds the response speed of the charging device, the control device sets the restriction start time according to the recovery time when the absolute value of the change speed of the basic command current recovers to less than the response speed of the charging device after exceeding the response speed of the charging device, the basic command current at the recovery time, and the response speed of the charging device, and gradually reduces the command current using the response speed of the charging device after reaching the restriction start time. In this way, the command current can be set more appropriately when reducing the command current.

[0010] In the vehicle-mounted power storage system of the present invention, the control device may estimate the change speed of the current of the power storage device when the command current changes during the external charging as the response speed of the charging device. In this way, the response speed of the charging device can be estimated more appropriately. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like symbols represent like elements, and in which:

[0012] Figure 1 1 is a schematic structural diagram showing the structure of an electric vehicle 20 and a charging station 80 including an on-vehicle power storage system as one embodiment of the present invention.

[0013] Figure 2 1 is a flowchart showing an example of a command current setting routine executed by the vehicle ECU 60 .

[0014] Figure 3 1 is a flowchart showing an example of a response speed estimation routine executed by vehicle ECU 60 .

[0015] Figure 4 1 is an explanatory diagram showing an example of the state of the command current Ic* and the current Ib of the battery 36 at the start of external charging.

[0016] Figure 5 1 is an explanatory diagram showing an example of the situation of the base command current Icbs, the absolute value of the base current change rate Vicbs, and the response speed Vch of the charging station 80 when a temporary excess occurs.

[0017] Figure 6 It is an explanatory diagram showing an example of the base command current Icbs, the command current Ic*, the absolute value of the base current change rate Vicbs, the absolute value of the command current change rate Vic*, and the response speed Vch of the charging station 80 during external charging.

[0018] Figure 7 1 is an explanatory diagram showing an example of the state of the command current Ic* and the current Ib of the battery 36 during external charging.

[0019] Figure 8 1 is a schematic structural diagram showing the structure of an electric vehicle 120 according to a modified example. DETAILED DESCRIPTION

[0020] Next, specific embodiments of the present invention will be described using examples.

[0021] Figure 11 is a schematic structural diagram showing the structure of an electric vehicle 20 and a charging pile 80 having an on-board power storage system as an embodiment of the present invention. As shown in the figure, the electric vehicle 20 of the embodiment has a motor 32 for driving, an inverter 34, a battery 36 as a power storage device, a driving power line 38, a system main relay 40, a charging power line 50, a vehicle connector 52, a charging relay 54, and a vehicle electronic control unit (hereinafter referred to as "vehicle ECU") 60. The on-board power storage system as an embodiment corresponds to the battery 36 and the vehicle ECU 60.

[0022] The motor 32 is configured as a synchronous generator motor, for example, and the rotor of the motor 32 is connected to the drive shaft DS, and the drive shaft DS is connected to the drive wheel DW via a differential gear. The inverter 34 is connected to the motor 32 and is also connected to the driving power line 38. The motor 32 is rotationally driven by switching control of a plurality of switching elements (not shown) of the inverter 34.

[0023] The battery 36 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the driving power line 38. The system main relay 40 is provided on the driving power line 38, and connects and disconnects the inverter 34 side and the battery 36 side.

[0024] One end of the charging power line 50 is connected to the inverter 34 side relative to the system main relay 40 of the driving power line 38, and the other end is connected to the vehicle connector 52. The vehicle connector 52 is configured to be connectable to the charging pile connector 82 of the charging pile 80 at a home, a charging station, etc. The charging relay 54 is provided on the charging power line 50, and performs connection and disconnection between the vehicle connector 52 side and the driving power line 38 side.

[0025] Although not shown in the figure, the vehicle ECU 60 has a microprocessor having a CPU, ROM, RAM, flash memory, input / output ports, and a communication port. Signals from various sensors are input to the vehicle ECU 60 via the input port. As the signal input to the vehicle ECU 60, for example, the rotation position θm of the rotor of the motor 32 from the rotation position sensor (e.g., a rotary transformer) 32a that detects the rotation position of the rotor of the motor 32 can be cited. The voltage Vb of the battery 36 from the voltage sensor 36a installed between the terminals of the battery 36, the current Ib of the battery 36 from the current sensor 36b installed at the output terminal of the battery 36, and the temperature Tb of the battery 36 from the temperature sensor 36c installed on the battery 36 can also be cited. A connection signal from the connection sensor 53 provided on the vehicle connector 52 can also be cited. In addition, the vehicle ECU 60 also functions as a drive control device for the vehicle, so the information required for driving control is also input to the vehicle ECU 60. Examples of such information include a start signal from a start switch, a shift position from a shift position sensor that detects an operating position of a shift lever, an accelerator opening from an accelerator pedal position sensor that detects an amount of accelerator pedal depression, a brake pedal position from a brake pedal position sensor that detects an amount of brake pedal depression, and a vehicle speed from a vehicle speed sensor.

[0026] Various control signals are output from the vehicle ECU 60 via the output port. As the signals output from the vehicle ECU 60, for example, switch control signals to the plurality of switch elements of the inverter 34, control signals to the system main relay 40, and control signals to the charging relay 54 can be cited. The vehicle ECU 60 calculates the power storage ratio SOC of the battery 36 based on the current Ib of the battery 36 from the current sensor 36b. The vehicle ECU 60 can communicate wirelessly with the charging pile electronic control unit (hereinafter referred to as "charging pile ECU") 86 of the charging pile 80 at a home, a charging station, etc.

[0027] The charging pile 80 includes a charging pile connector 82, a charger 84, and a charging pile ECU 86. The charging pile connector 82 is configured to be connectable to the vehicle connector 52 of the electric vehicle 20. The charger 84 is connected to an external power source 90 configured as an AC power source such as a household power source or a commercial power source and the charging pile connector 82. When the vehicle connector 52 is connected to the charging pile connector 82 to indicate charging of the battery 36, the charger 84 converts the AC power from the external power source 90 into DC power, adjusts the power (voltage, current), and supplies it to the electric vehicle 20.

[0028] Although not shown in the figure, the charging pile ECU86 has a microprocessor with a CPU, ROM, RAM, flash memory, input and output ports, and a communication port. Signals from various sensors are input to the charging pile ECU86 via the input port. As signals input to the charging pile ECU86, for example, the output voltage Vc of the charger 84 from the voltage sensor 85a installed between the terminals on the output side of the charger 84, and the output current Ic of the charger 84 from the current sensor 85b installed at the output terminal of the charger 84 can be cited. Various control signals are output from the charging pile ECU86 via the output port. As signals output from the charging pile ECU86, for example, a control signal to the charger 84 can be cited. The charging pile ECU86 can communicate wirelessly with the vehicle ECU60 of the electric car 20.

[0029] In the electric vehicle 20 of the embodiment thus constituted, when the vehicle connector 52 is connected to the charging station connector 82 when the electric vehicle 20 is parked at a home, a charging station, or the like due to system shutdown, a connection signal is transmitted from the connection sensor 53 to the vehicle ECU 60, and the vehicle ECU 60 detects the connection between the vehicle connector 52 and the charging station connector 82. Next, when the user instructs external charging to charge the battery 36 using power from the external power source 90 (charging station 80), the vehicle ECU 60 initially turns on the system main relay 40 and the charging relay 54. Then, the vehicle ECU 60 transmits the command current Ic* for external charging to the charging station ECU 86, and the charging station ECU 86 controls the charger 84 so that the output current Ic of the charger 84 becomes the command current Ic*. In this way, external charging is performed. Then, when the storage ratio SOC of the battery 36 reaches a predetermined storage ratio Sch (for example, about 80% to 95%), the vehicle ECU 60 transmits an external charging end instruction to the charging station ECU 86, and the charging station ECU 86 stops the charger 84 when receiving the instruction. External charging is thus terminated. Thereafter, vehicle ECU 60 turns off system main relay 40 and charging relay 54 .

[0030] Next, the operation of the electric vehicle 20 of the embodiment configured as described above, particularly the process of setting the command current Ic* by the vehicle ECU 60 during external charging, will be described. Figure 2 2 is a flowchart showing an example of a command current setting routine executed by the vehicle ECU 60. This routine is repeatedly executed during external charging.

[0031] When executing Figure 2When the command current setting routine is executed, the vehicle ECU 60 inputs data such as the power storage ratio SOC and the temperature Tb of the battery 36 (step S100). Here, the power storage ratio SOC of the battery 36 is inputted as a value calculated based on the current Ib of the battery 36 detected by the current sensor 36b. The temperature Tb of the battery 36 is inputted as a value detected by the temperature sensor 36c.

[0032] When the vehicle ECU 60 inputs the data in this way, it sets the basic command current Icbs[t] at each time t in the future (from the most recent time t1 to time t2 which is a certain degree later than time t1) according to the input power storage ratio SOC and temperature Tb of the battery 36 (step S110). Here, the basic command current Icbs[t] at each time t is a basic value of the command current Ic*[t] at each time t, and can be set by applying the power storage ratio SOC and temperature Tb of the battery 36 to the basic command current setting map, for example. The basic command current setting map is set in advance through experiments and analysis as the relationship between the power storage ratio SOC and temperature Tb of the battery 36 and the basic command current Icbs[t] at each time t, and is stored in the ROM or flash memory of the vehicle ECU 60.

[0033] Next, the vehicle ECU 60 sets the base current change rate Vicbs[t] at each time t from time t1 to time t2 except for time t1 (step S120). Here, the base current change rate Vicbs[t] at each time t is the amount of change per unit time of the base command current Icbs[t] at each time t, and can be calculated, for example, by subtracting the base command current Icbs[t-Δt1] at time (t-Δt1) from the base command current Icbs[t] at time t and dividing it by the time interval Δt1 between time t and time (t-Δt1).

[0034] Then, the vehicle ECU 60 determines whether the response speed Vch of the charging station 80 during external charging has been estimated (step S130). Here, the response speed Vch of the charging station 80 is a speed related to the response delay from the time when the vehicle ECU 60 sends the command current Ic* to the charging station ECU 86 to the time when the charging station ECU 86 controls the charger 84 and reflects the current Ib of the battery 36. Figure 3 The response speed estimation routine is used to calculate. Figure 2 Description of the command current setting routine, description Figure 3 Response speed estimation routine.

[0035] When external charging is instructed, execution begins Figure 3When executing this routine, the vehicle ECU 60 first inputs the command current Ic* (step S300). Here, the command current Ic* is set to a value of 0 by the vehicle ECU 60, or Figure 2 The command current setting routine is used to set the value before the input is sent to the charging pile ECU 86 of the charging pile 80.

[0036] Next, the vehicle ECU 60 calculates the command current change rate Vic* by dividing the value obtained by subtracting the previous command current (previous Ic*) from the command current Ic* by the time interval Δt2, which is the acquisition interval of the command current Ic* (step S310), and the vehicle ECU 60 compares the absolute value of the calculated command current change rate Vic* with the threshold value Vicref (step S320). Here, the time interval Δt2 is set to be the same as the above-mentioned time interval t1. The threshold value Vicref is a threshold value for determining whether the command current Ic* changes greatly to a certain extent. In the embodiment, at the start of external charging, the command current Ic* is changed from a value of 0 to a relatively large positive value Ic1 in a step-like manner. Therefore, the processing of step S320 is a processing for determining whether the vehicle ECU 60 is before or at the start of external charging. When the absolute value of the command current change rate Vic* is less than the threshold value Vicref in step S320, it is determined that it is before the start of external charging, and the process returns to step S300.

[0037] When the absolute value of the command current change rate Vic* is greater than the threshold value Vicref in step S320, the vehicle ECU 60 determines that external charging has started, and starts counting the time td (step S330). Next, the vehicle ECU 60 inputs the command current Ic* and the current Ib of the battery 36 in the same manner as in step S300 (step S340). Here, the value detected by the current sensor 36b is input for the current Ib of the battery 36.

[0038] Then, the current Ib of the battery 36 is subtracted from the command current Ic* to calculate the current difference ΔI (step S350), and the absolute value of the calculated current difference ΔI is compared with the threshold ΔIref (step S360). Here, the threshold ΔIref is a threshold for determining whether the current Ib of the battery 36 is sufficiently close to the command current Ic*. When the absolute value of the current difference ΔI is greater than the threshold ΔIref, it is determined that the current Ib of the battery 36 is not sufficiently close to the command current Ic*, and the process returns to step S340.

[0039] In step S360, when the absolute value of the current difference ΔI is below the threshold ΔIref, the vehicle ECU 60 determines that the current Ib of the battery 36 is sufficiently close to the command current Ic*, and divides the absolute value of the command current change rate Vic* calculated in step S310 by the time td to obtain a value that is estimated as the response speed Vch of the charging pile 80 (step S370), thereby terminating this routine.

[0040] Figure 4 1 is an explanatory diagram showing an example of the state of the command current Ic* and the current Ib of the battery 36 at the start of external charging. Figure 4 In the example, at time t11, the command current Ic* is changed from value 0 to positive value Ic1 in a step-like manner, and at the subsequent time t12, the current Ib of the battery 36 is sufficiently close to the command current Ic*. In this case, the value obtained by subtracting the value 0 from the value Ic1 is equivalent to the command current change rate Vic*, and the time (t12-t11) is equivalent to the time td. Therefore, the rising speed of the current Ib of the battery 36 obtained by dividing the value Ic1 by the time (t12-t11) is calculated as the response speed Vch of the charging pile 80.

[0041] Return to Figure 2 Description of the command current setting routine. When it is determined in step S130 that the response speed Vch of the charging pile 80 has not been estimated, the vehicle ECU 60 sets the basic command current Icbs[t1] at the most recent time t1 as the command current Ic*, sends it to the charging pile ECU 86 (step S200), and ends this routine. In addition, as described above, at the beginning of external charging, the command current Ic* is changed from a value of 0 to a relatively large positive value Ic1 in a step-like manner.

[0042] When it is determined in step S130 that the response speed Vch of the charging pile 80 has been estimated, the vehicle ECU 60 inputs the response speed Vch of the charging pile 80 (step S140). Next, the vehicle ECU 60 observes the basic command current Icbs[t] at each time t from time t1 to t2 in a time series order, and predicts whether to reduce the basic command current Icbs (command current Ic*) (step S150). When it is predicted that the basic command current Icbs (command current Ic*) is reduced, the vehicle ECU 60 observes the basic current change speed Vicbs[t] at each time t from time t1 to t2 in a time series order, and predicts whether the absolute value of the basic current change speed Vicbs temporarily exceeds the response speed Vch of the charging pile 80 (step S160). When it is predicted in step S150 that the basic command current Icbs (command current Ic*) will not decrease, when it is predicted in step S150 that the basic command current Icbs will decrease and it is predicted in step S160 that no temporary exceeding will occur, the vehicle ECU60 sets the basic command current Icbs[t1] at the most recent moment t1 as the command current Ic*, sends it to the charging pile ECU86 (step S200), and ends this routine.

[0043] Here, the processing of step S150 can be performed, for example, by comparing the basic command current Icbs[t] at each time t with the basic command current Icbs[t-Δt1] at the time (t-Δt1) in a time series order. The processing of step S160 can be performed, for example, by comparing the basic current change rate Vicbs[t] at each time t with the response rate Vch of the charging pile 80 in a time series order. During external charging, when the storage ratio SOC of the battery 36 is close to the predetermined storage ratio Sch, the basic command current Icbs is reduced for the purpose of suppressing overvoltage, overcharging, etc. of the battery 36. At this time, the absolute value of the basic current change rate Vicbs temporarily increases. When the response speed Vch of the charging pile 80 is relatively low, a temporary excess may occur. The processing of steps S150 and S160 is a processing that takes this situation into consideration. Figure 5 1 is an explanatory diagram showing an example of the situation of the base command current Icbs, the absolute value of the base current change rate Vicbs, and the response speed Vch of the charging station 80 when a temporary excess occurs. Figure 5 , explaining the processing when a temporary overrun occurs.

[0044] When it is predicted in step S150 that the basic command current Icbs (command current Ic*) will decrease and it is predicted in step S160 that a temporary excess will occur, the vehicle ECU60 sets the recovery time Tre and the recovery current Icre (step S170). Here, the recovery time Tre is the moment when the absolute value of the basic current change speed Vicbs exceeds the response speed Vch of the charging pile 80 and recovers to less than the response speed Vch, and the recovery current Icre is the basic command current Icbs[Tre] at the recovery time Tre. This processing can be performed, for example, by comparing the basic current change speed Vicbs[t] at each time t from time t1 to t2 with the response speed Vch of the charging pile 80. Figure 5 In the example of FIG. 1 , time t21 is set as the recovery time Tre, and the base command current Icbs[t21] at time t21 is set as the recovery current Icre.

[0045] Next, the vehicle ECU 60 sets the restriction start time Tlis (step S180) according to the recovery time Tre, the recovery current Icre, the response speed Vch of the charging pile 80, the time t1-t2, and the basic command current Icbs[t] at each time t before the time t1. Here, for the basic command current Icbs[t] at each time t before the time t1, the value set when executing this routine in the past is used. The restriction start time Tlis is the time when the restriction process of limiting the command current Ic* to the basic command current Icbs should be started. The processing of step S180 can be performed, for example, in the following manner: while changing the time t in reverse time series from the recovery time Tre, the recovery current Icre and the response speed Vch of the charging pile 80 are used to calculate the limiting current Ili[t] at the time t by formula (1) and compare the limiting current Ili[t] at the time t with the basic command current Icbs[t], and the earliest time that satisfies the condition that the limiting current Ili is less than the basic command current Icbs is set as the limiting start time Tlis. It can be seen from formula (1) that the limiting current Ili increases in reverse time series order according to the slope of the response speed Vch of the charging pile 80. Figure 5 In the example, the current value at each time t on the dotted straight line L corresponding to equation (1) is set as the limiting current Ili[t], and the earliest time t22 that satisfies the condition that the limiting current Ili is less than the basic command current Icbs is set as the limiting start time Tlis.

[0046] Ili[t]=Icre-Vch·(t-Tre) (1)

[0047] Then, the value obtained by subtracting the most recent moment t1 from the restriction start moment Tlis is compared with the value 0 (step S190). This process is to determine whether to start the above-mentioned restriction process. When the value obtained by subtracting the moment t1 from the restriction start moment Tlis is positive, the vehicle ECU 60 determines that the restriction process will not be started, and the vehicle ECU 60 sets the basic command current Icbs[t1] at the most recent moment t1 to the command current Ic* and sends it to the charging pile ECU 86 (step S200), and ends this routine.

[0048] When the value obtained by subtracting time t1 from the restriction start time Tlis in step S190 is less than the value 0, the vehicle ECU60 determines that the restriction processing has started, and the vehicle ECU60 sets the value obtained by subtracting the response speed Vch of the charging pile 80 from the previous command current Ic* as the command current Ic*, and sends it to the charging pile ECU86 (step S210), and compares the command current Ic* with the recovery current Icre (step S220). When the command current Ic* is larger than the recovery current Icre, the vehicle ECU60 returns to step S210. In this way, steps S210 and S220 are repeated, so that as a restriction processing, the command current Ic* is reduced according to the response speed Vch. The command current Ic* at this time roughly corresponds to the above-mentioned limit current Ili. Therefore, when the basic command current Icbs (command current Ic*) is reduced after the response speed Vch of the charging pile 80 is inferred, the command current change speed Vic* (which can be compared with Figure 3 The absolute value of Vch is greater than the response speed Vch of the charging pile 80. Thus, even when the response speed Vch of the charging pile 80 is relatively low, the followability of the current Ib of the battery 36 relative to the command current Ic* when the command current Ic* is reduced can be suppressed, and the occurrence of unfavorable conditions such as overvoltage and overcharging of the battery 36 can be suppressed. As a result, the battery 36 can be charged more appropriately.

[0049] When the command current Ic* reaches or falls below the recovery current Icre in step S220, the vehicle ECU 60 terminates the restriction process and terminates this routine. If it is considered that the command current Ic* becomes or falls below the recovery current Icre during the decrease of the base command current Icbs (command current Ic*), the process of steps S100 to S160 and S200 is basically performed the next time this routine is executed. In addition, when the power storage ratio SOC of the battery 36 reaches the predetermined power storage ratio Sch before the command current Ic* reaches or falls below the recovery current Icre, the external charging is terminated as described above, thereby terminating the restriction process.

[0050] Figure 6This is an explanatory diagram showing an example of the situation of the base command current Icbs, the command current Ic*, the absolute value of the base current change rate Vicbs, the absolute value of the command current change rate Vic*, and the response speed Vch of the charging station 80 during external charging. Figure 3 The processing of step S310 of the response speed estimation routine is similarly calculated. Figure 6 In the example, regarding the time t21 (recovery time Tre), the basic command current Icbs[t21] (recovery current Icre), and the time t22 (limitation start time Tlis), Figure 5 same.

[0051] like Figure 6 As shown, during external charging, before the restriction start time Tlis, the basic command current Icbs is set to the command current Ic*, after the restriction start time Tlis, the command current Ic* is decreased from the previous value according to the response speed Vch of the charging pile 80, and after the recovery time Tre, the basic command current Icbs is set to the command current Ic*. Therefore, it is possible to suppress the absolute value of the command current change speed Vic* from becoming larger than the response speed Vch of the charging pile 80 after the response speed Vch of the charging pile 80 is estimated. Therefore, even when the response speed Vch of the charging pile 80 is relatively low, it is possible to suppress the follow-up of the decrease of the current Ib of the battery 36 relative to the command current Ic* when the command current Ic* is decreased, and it is possible to suppress the occurrence of undesirable situations such as overvoltage and overcharging of the battery 36. As a result, the battery 36 can be charged more appropriately. In addition, when the command current Ic* is increased at the beginning of external charging, the current Ib of the battery 36 is smaller than the command current Ic* (the current Ib increases with a delay relative to the command current Ic*), so even if the command current change speed Vic* becomes greater than the response speed Vch of the charging pile 80, it is not easy to cause undesirable situations such as overvoltage and overcharging of the battery 36.

[0052] In the electric vehicle 20 of the embodiment described above, during external charging, the vehicle ECU 60 sends the command current Ic* based on the basic command current Icbs to the charging pile ECU 86, and the charging pile ECU 86 controls the charger 84 according to the command current Ic*. In this case, the vehicle ECU 60 calculates the rising speed of the storage battery 36 at the start of external charging (when the command current Ic* increases from the value 0 to the value Ic1) as the response speed Vch of the charging pile 80. After that, when it is predicted that the basic command current Icbs decreases and a temporary overshoot is predicted, the vehicle ECU 60 sets the command current Ic* such that the command current change speed Vic* becomes the response speed Vch of the charging pile 80. Thus, even when the response speed Vch of the charging pile 80 is relatively low, it is possible to suppress the deterioration of the followability of the decrease in the current Ib of the storage battery 36 with respect to the command current Ic* when the command current Ic* decreases, and it is possible to suppress the occurrence of adverse conditions such as overvoltage and overcharging of the storage battery 36. As a result, the charging of the storage battery 36 can be performed more appropriately.

[0053] In the electric vehicle 20 of the embodiment, as Figure 4 shown, the rising speed of the current Ib of the storage battery 36 at the start of external charging, that is, when the command current Ic* changes stepwise from the value 0 to a relatively large positive value Ic1, is calculated as the response speed Vch of the charging pile 80. However, the electric vehicle 20 may also be as Figure 7 shown. After the start of external charging, for the calculation of the response speed Vch, after the command current Ic* decreases from the value Ic1 to the value Ic2 (0 ≤ Ic2 < Ic1) and then returns to the value Ic1, the absolute value of the command current change speed Vic* (= Ic2 - Ic1) is divided by the time td (= t14 - t13), and the resulting decrease speed of the current Ib of the storage battery 36 is calculated as the response speed Vch of the charging pile 80. As described above, since the problem is a temporary overshoot when the basic command current Icbs decreases, it is preferable to calculate the decrease speed of the current Ib of the storage battery 36 as the response speed Vch of the charging pile 80 as in the modified example, rather than calculating the rising speed of the current Ib of the storage battery 36 as the response speed Vch of the charging pile 80 as in the embodiment. In addition, the value Ic2 is set within the range where the protection of the storage battery 36 can be ensured when the current Ib of the storage battery 36 decreases with a delay with respect to the command current Ic*.

[0054] In the electric vehicle 20 of the embodiment, during external charging, the restriction start time Tlis is set in step S180, and when the value (Tlis-t1) obtained by subtracting the time t1 from the restriction start time Tlis in step S190 is positive, the restriction process is not started, and when the value (Tlis-t1) in step S190 is less than the value 0, the restriction process is started. However, the above formula (1) can also be used to calculate the limit current Ili[t] at the time t1, and when the limit current Ili[t1] at the time t1 is greater than the basic command current Icbs[t1], the restriction process is not started, and when the limit current Ili[t1] is less than the basic command current Icbs[t1], the restriction process is started.

[0055] In the electric vehicle 20 of the embodiment, during external charging, when the base command current Icbs is predicted to decrease and a temporary excess is predicted to occur, the command current Ic* is set so that the command current change speed Vic* becomes the response speed Vch of the charging pile 80. However, at this time, the command current Ic* may be set so that the command current change speed Vic* becomes less than the response speed Vch. For example, the command current Ic* may be set so that the command current change speed Vic* becomes a change speed slightly lower than the response speed Vch.

[0056] In the electric vehicle 20 of the embodiment, a charging power line 50 for charging (DC charging) using direct current power, a vehicle connector 52, and a charging relay 54 are provided. Figure 8 The structure of the electric vehicle 120 is shown in a modified example. Figure 8 The electric car 120 does not have a charging power line 50, a vehicle connector 52, and a charging relay 54, but has a charging device 68 for charging (AC charging) based on AC power. Figure 1 The charging device 68 includes a charging power line 70 , a vehicle connector 72 , a charger 74 , and a charging electronic control unit (hereinafter referred to as “charging ECU”) 76 .

[0057] One end of the charging power line 70 is connected to the battery 36 side relative to the system main relay 40 of the driving power line 38, and the other end is connected to the vehicle connector 72. The vehicle connector 72 is configured to be connectable to a power connector, and the power connector is connected to an external power source 90 of AC such as a home or a charging station. The charger 74 is provided on the charging power line 70, and is configured to convert AC power from the external power source into DC power, and adjust the voltage (power) to supply it to the battery 36 side.

[0058] Although not shown in the figure, the charging ECU 76 has a microprocessor having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. Signals from various sensors are input to the charging ECU 76 via the input port. As the signal input to the charging ECU 76, for example, a connection signal from a connection sensor 73 provided in the vehicle connector 72 can be cited. Various control signals are output from the charging ECU 76 via the output port. As the signal output from the charging ECU 76, for example, a control signal to the charger 74 can be cited. The charging ECU 76 can communicate with the vehicle ECU 60.

[0059] In the electric vehicle 120 of the modified example configured in this way, when the vehicle connector 72 is connected to the power connector 92 when the electric vehicle 120 is parked at a home, a charging station, or the like due to system shutdown, a connection signal is sent from the connection sensor 73 to the vehicle ECU 60 via the charging ECU 76, and the charging ECU 76 and the vehicle ECU 60 detect the connection between the vehicle connector 72 and the power connector 92. Next, when the user instructs external charging to charge the battery 36 using power from the external power supply 90, the vehicle ECU 60 sends a command current Ic2* for external charging to the charging ECU 76, and the charging ECU 76 controls the charger 74 so that the current Ic2 on the output side of the charger 74 becomes the command current Ic2*. In this way, external charging is performed. Then, when the storage ratio SOC of the battery 36 reaches the predetermined storage ratio Sch, the vehicle ECU 60 sends a termination command for external charging to the charging ECU 76, and the charging ECU 76 stops the charger 74 when receiving the termination command. In this way, external charging is terminated.

[0060] In the electric vehicle 120 of this modification, the Figure 3 Response speed estimation routine, Figure 2 By calculating the response speed Vch2 of the charging device 68 or setting the command current Ic2* in the same routine as the command current setting routine of the embodiment, the same effect as that of the embodiment can be achieved.

[0061] The electric vehicle 20 of the embodiment is provided with a charging power line 50 for DC charging, a vehicle connector 52, and a charging relay 54. In addition, the electric vehicle 120 of the modified example is provided with a charging device 68 for AC charging (charging power line 70, vehicle connector 72, charger 74). However, the electric vehicle 120 may also be provided with a charging power line 50 for DC charging, a vehicle connector 52, a charging relay 54, and a charging device 68 for AC charging (charging power line 70, vehicle connector 72, charger 74).

[0062] In the electric vehicles 20 and 120 of the embodiment and the modified example, the battery 36 is used as the power storage device. However, in the electric vehicles 20 and 120, a capacitor may be used as the power storage device.

[0063] In the embodiment, the on-board power storage system is installed in the electric car 20 having the motor 32 and the battery 36. However, the on-board power storage system may be installed in a vehicle other than the electric car 20, for example, a hybrid car having an engine in addition to the same structure as the electric car 20, a fuel cell car having a fuel cell in addition to the same structure as the electric car 20, or the like.

[0064] The correspondence between the main elements of the embodiment and the main elements of the invention described in the Summary of the Invention section will be described. In the embodiment, the battery 36 corresponds to the "power storage device" and the vehicle ECU 60 corresponds to the "control device".

[0065] In addition, the embodiment is an example for specifically explaining the method for implementing the invention described in the Summary of the Invention section, so the correspondence between the main elements of the embodiment and the main elements of the invention described in the Summary of the Invention section does not limit the elements of the invention described in the Summary of the Invention section. That is, the interpretation of the invention described in the Summary of the Invention section should be carried out based on the description of the part, and the embodiment is only a specific example of the invention described in the Summary of the Invention section.

[0066] As mentioned above, although the specific embodiment of the present invention is described using the embodiment, the present invention is not limited to such embodiment at all, and it is needless to say that the present invention can be implemented in various forms within the scope not departing from the gist of the present invention.

[0067] The present invention can be used in the manufacturing industry of vehicle-mounted power storage systems, etc.

Claims

1. A vehicle-mounted power storage system, mounted on a vehicle, comprising: an electrical storage device; and The control device transmits a command current for external charging to the charging device during external charging in which the power storage device is charged by the charging device using electric power from an external power source, in, During the external charging, the control device estimates the response speed of the charging device based on the change in the current of the power storage device accompanying the change in the command current after the charging starts, and sets the command current in consideration of the response speed of the charging device after estimating the response speed of the charging device. When the control device reduces the command current after estimating the response speed of the charging device during the external charging, the control device sets the command current so that the change speed of the command current becomes less than the response speed of the charging device. The control device sets the command current according to a basic command current based on a power storage ratio of the power storage device during the external charging. When the control device reduces the basic command current after inferring the response speed of the charging device during external charging, when the absolute value of the change speed of the basic command current temporarily exceeds the response speed of the charging device, the control device sets a restriction start time based on the recovery time when the absolute value of the change speed of the basic command current recovers to below the response speed of the charging device after exceeding the response speed of the charging device, the basic command current at the recovery time, and the response speed of the charging device, and after reaching the restriction start time, the command current is gradually reduced using the response speed of the charging device.

2. The vehicle-mounted power storage system according to claim 1, wherein: The control device estimates, during the external charging, a change speed of the current of the power storage device when the command current changes as a response speed of the charging device.

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