JP7647645B2 - Electric car with solar panels - Google Patents

Description

The technology disclosed in this specification relates to an electric vehicle equipped with solar panels that can charge a battery.

Patent document 1 discloses an electric vehicle in which the user can change the upper limit of the remaining battery power. Patent document 2 discloses an electric vehicle in which the battery can be charged using a solar panel.

JP 2013-005485 A JP 2019-126219 A

It is conceivable that when the remaining power of the battery falls below a predetermined lower limit, the driving of the motor for driving is prohibited, and when the remaining power recovers to the upper limit, the prohibition of driving the motor is lifted. It is also conceivable that the upper limit can be changed by the user, as in the technology of Patent Document 1. For example, the user may select a relatively large upper limit candidate value from among the upper limit candidate values, assuming long-distance travel. If only short-distance travel is assumed, it is advisable to select a relatively small upper limit candidate value. On the other hand, when charging using a solar panel, it is better to charge the battery as much as possible in order to make effective use of natural energy. When charging using an external power source, it is desirable to be able to use a process that prohibits the driving of the motor until the remaining power recovers (driving prohibition process) and a charging process using the solar panel (solar panel charging process) in combination. This specification provides a technology that aligns the driving prohibition process and the solar panel charging process.

The electric vehicle disclosed in this specification comprises a battery that supplies power to a driving motor, a power receiving socket for connecting a power plug of an external power source, a solar panel connected to the battery, a main controller, an external charging controller, and a solar charging controller. The main controller prohibits the driving of the motor when the remaining power of the battery falls below a predetermined lower limit. When the external charging controller detects that a current is flowing from the power receiving socket to the battery, it sends an external charging signal to the main controller. The solar charging controller monitors the charging of the battery by the solar panel.

The main controller is programmed to perform the following processes: (1) The main controller sets the upper limit value to a candidate upper limit value selected by the user from among multiple candidate upper limit values. (2) When the battery is being charged by an external power source, the main controller stops charging from the external power source when the remaining power of the battery reaches the upper limit value. (3) The main controller releases the prohibition on driving the motor on the condition that an external charging signal is received and the remaining power has recovered to an upper limit value greater than the lower limit value. (4) When the main controller detects that the power supply plug has been inserted into the power receiving socket when the remaining power has reached the upper limit value, it prohibits charging from the solar panel. (5) When charging of the battery from the solar panel begins, the main controller updates the upper limit value to a predetermined temporary upper limit value that is equal to or less than the smallest candidate upper limit value among the candidate upper limit values. The solar charging controller sends an external charging signal to the main controller when the battery is charged by the solar panel and the remaining power of the battery reaches the temporary upper limit value.

Without the process of (5) and the process of the solar charging controller, the following inconveniences will occur. For example, if the battery's remaining power exceeds the upper limit when it is charged by the power of the solar panel after the motor drive is prohibited, the prohibition on the motor drive may not be lifted. This is because the remaining power exceeds the upper limit, so charging from an external power source will not start even if the power receiving socket is connected. Since no current flows from the power receiving socket to the battery, an external charging signal is not sent to the main controller, and the prohibition on the motor drive cannot be lifted. On the other hand, when the power supply plug is inserted, charging from the solar panel is prohibited, so the battery cannot be charged by the solar panel either. In this way, there is a risk of inconsistency between the drive prohibition process and the solar panel charging process.

When the electric vehicle described above is being charged using solar panels, the motor drive prohibition is lifted when the remaining power reaches the temporary upper limit. Therefore, there is no inconsistency between the drive prohibition process and the solar panel charging process.

Details and further improvements of the technology disclosed in this specification are explained in the "Description of Embodiments" below.

FIG. 2 is a block diagram of a power system of the electric vehicle according to the embodiment. 13 is a flowchart of a drive inhibition process executed by a main controller. 4 is a flowchart of a solar panel charging process executed by a solar charging controller.

An electric vehicle 10 according to the embodiment will be described with reference to the drawings. FIG. 1 shows a block diagram of the power system of the electric vehicle 10. The electric vehicle 10 according to the embodiment has an electric motor (motor 14) for driving. The output shaft of the motor 14 is connected to the drive wheels 16 via a differential gear 15.

The motor 14 receives power from the battery 11. An inverter 13 is connected between the battery 11 and the motor 14. The inverter 13 converts the DC power output by the battery 11 into three-phase AC power suitable for driving the motor 14. The inverter 13 is controlled by the main controller 30. Note that the dashed arrows in Figure 1 represent signal lines.

A system relay 12 is connected between the battery 11 and the inverter 13. When the main controller 30 is in a situation in which it is acceptable to drive the motor 14, it closes the system relay 12 and connects the battery 11 to the inverter 13. When the system relay 12 is closed, the electric vehicle 10 is ready to run.

When the main controller 30 prohibits the driving of the motor 14, it opens the system relay 12 and electrically disconnects the inverter 13 and the motor 14 from the battery 11. Driving of the motor 14 is prohibited when the main switch of the electric vehicle 10 is off (or when the accessory is on). As will be described in detail later, the main controller 30 also prohibits driving of the motor 14 when the remaining power of the battery 11 falls below a predetermined lower limit. In other words, the main controller 30 opens the system relay 12 when the remaining power of the battery 11 falls below a predetermined lower limit.

The battery 11 can be charged by an external power source 90, and can also be charged by a solar panel 17. The electric vehicle 10 is equipped with a power receiving socket 20 and an external charging controller 21. The power receiving socket 20 is connected to the external charging controller 21, which is connected to the battery 11. A power supply plug 91 of an external power source 90 can be connected to the power receiving socket 20. Power from the external power source 90 is sent to the battery 11 via the power supply plug 91, the power receiving socket 20, and the external charging controller 21. In FIG. 1, the external power source 90 and the power supply plug 91 are shown by phantom lines.

When the external power source 90 is AC power, the external charging controller 21 converts the supplied AC power into DC power and supplies it to the battery 11. Furthermore, when the external charging controller 21 detects that a current has flowed from the power receiving socket 20 to the battery 11, it transmits a signal (external charging signal) to the main controller 30 to inform the main controller 30. In other words, the external charging controller 21 controls the charging of the battery 11 by the external power source 90, and when it detects that a current has flowed from the power receiving socket 20 to the battery 11, it transmits an external charging signal to the main controller 30.

The solar panel 17 is a device that converts sunlight into electricity. The solar panel 17 is installed on the roof of the electric vehicle 10. The solar panel 17 is connected to the battery 11 via the solar charge controller 18. The solar charge controller 18 converts the electricity generated by the solar panel 17 into a voltage suitable for charging the battery 11. In other words, the solar charge controller 18 controls the charging of the battery 11 by the solar panel 17.

Voltage sensors 19 are provided on both ends of the battery 11, and the main controller 30 obtains the voltage of the battery 11 from the measurement value of the voltage sensor 19. A predetermined relationship is established between the voltage of the battery 11 and the remaining power. The main controller 30 estimates the remaining power of the battery 11 from the voltage of the battery 11. When the battery 11 is charged by power supplied from the external power source 90, if the remaining power of the battery 11 exceeds a predetermined upper limit, the main controller 30 stops charging the battery 11 from the external power source 90. When charging the battery 11 by the solar panel 17, the battery 11 may be charged beyond the upper limit.

In addition, a relay (not shown) is connected between the battery 11 and the solar charging controller 18 and the external charging controller 21. The main controller 30 closes the relay when charging the battery 11 and opens the relay when charging is completed.

The main controller 30 controls the input and output of the battery 11 so that the remaining power of the battery 11 does not fall below a predetermined lower limit. The upper limit can be set (selected) by the user. The electric vehicle 10 is equipped with an input device 31. The user operates the input device 31 to select a desired upper limit candidate value from among multiple upper limit candidate values. The multiple upper limit candidate values are set to different values. For example, 90%, 80%, and 60% of full charge are prepared in advance as multiple upper limit candidate values.

The main controller 30 stores the upper limit candidate value selected by the user in the upper limit value memory area of the storage device. In other words, when the user selects a new upper limit candidate value, the main controller 30 updates the upper limit value with the new upper limit candidate value.

For example, if the user plans to travel long distances, the user selects a large upper limit candidate value. If only short distance travel is envisioned, the user selects a relatively small upper limit candidate value. When the remaining power of the battery 11 falls below the lower limit, the main controller 30 prohibits the motor 14 from being driven until the remaining power reaches the set upper limit. This process prevents the electric vehicle 10 from moving until the remaining power of the battery 11 reaches the upper limit desired by the user. Alternatively, the main controller 30 may output a warning message to the instrument panel indicating that the remaining power is low when the remaining power falls to a specified warning value. The warning value is set to a value slightly higher than the lower limit.

As mentioned above, the battery 11 can be charged with electricity generated by the solar panel 17. The solar panel 17 is installed on the roof of the electric vehicle 10, and can generate electricity when exposed to sunlight. In order to effectively utilize natural energy, the main controller 30 may permit charging of the battery 11 when charging using the solar panel 17, even if the charging exceeds the upper limit value described above.

The main processes executed by the main controller 30 are listed below. (1) The main controller 30 sets the upper limit candidate value selected by the user from among multiple upper limit candidate values. (2) When the battery 11 is being charged by the external power source 90, the main controller 30 stops charging from the external power source 90 when the remaining power of the battery reaches the upper limit. However, as described above, the main controller 30 may allow charging from the solar panel 17 even after the remaining power exceeds the upper limit. (3) The main controller 30 releases the prohibition on driving the motor on the condition that an external charging signal is received and the remaining power of the battery has recovered to an upper limit value that is greater than the lower limit. (4) When the main controller 30 detects that the power supply plug 91 has been inserted into the power receiving socket 20 when the remaining power of the battery 11 has reached the upper limit, it prohibits charging from the solar panel 17. The power receiving socket 20 is equipped with a plug detector 22 (see FIG. 1), and when the power supply plug 91 is inserted into the power receiving socket 20, the plug detector 22 sends a signal to the main controller 30 to notify the main controller 30. (5) When charging of the battery 11 by the solar panel 17 begins, the main controller 30 updates the upper limit with a predetermined temporary upper limit. In other words, it sets the temporary upper limit to a new upper limit. The temporary upper limit is set to a value equal to or less than the smallest upper limit candidate value among the upper limit candidate values.

A flowchart of the drive inhibition process executed by the main controller 30 is shown in Figure 2. The drive inhibition process will be explained with reference to Figure 2. Note that SOC in Figure 2 is an abbreviation for State Of Charge, and means the remaining amount of power in the battery 11. SOC is expressed as a ratio (percentage) of the current remaining amount of power to the amount of power when the battery 11 is fully charged.

The main controller 30 constantly monitors the remaining power (SOC) and prohibits the driving of the motor 14 when the remaining power falls below a predetermined lower limit (steps S12: YES, S13). If the remaining power falls below the lower limit while driving, the main controller 30 displays a warning on the instrument panel to the effect that the driving of the motor 14 will be prohibited when a predetermined margin of power is subsequently consumed.

As mentioned above, the battery 11 can be charged by the external power source 90 or by the solar panel 17. When the power supply plug 91 of the external power source 90 is connected to the power receiving socket 20, charging of the battery 11 begins with the external power source 90. Also, as mentioned above, when the external charging controller 21 detects that a current has flowed from the power receiving socket 20 to the battery 11, it sends an external charging signal to the main controller 30.

When the remaining power of the battery 11 has recovered to the set upper limit and an external charging signal has been received, the main controller 30 ends charging from the external power source 90 and releases the prohibition on driving the motor 14 (steps S14: NO, S16: YES, S17). That is, the main controller 30 closes the system relay 12 and connects the battery 11 to the inverter 13. When the battery 11 is connected to the inverter 13, the electric vehicle 10 is ready to run.

When the battery 11 is charged by the solar panel 17, the main controller 30 changes the upper limit value. After the remaining power of the battery 11 falls below the lower limit value (step S12: YES), the solar panel 17 starts generating power, and when the battery 11 starts to be charged with the power of the solar panel 17, the main controller 30 updates the upper limit value with the temporary upper limit value (steps S14: YES, S15). Here, the temporary upper limit value is set to a value equal to or less than the smallest upper limit candidate value among the multiple upper limit candidate values.

On the other hand, as described below, when the SOC (remaining power) of the battery 11 reaches a temporary upper limit during charging by the solar panel 17, the solar charging controller 18 sends an external charging signal to the main controller 30. The external charging signal is originally a signal sent by the external charging controller 21 to the main controller 30, but it is a convenient signal for coordinating charging by the solar panel 17 with the drive prohibition process of the motor 14.

After step S15 is executed, when the remaining power of the battery 11 recovers to the upper limit (temporary upper limit), an external charging signal is sent from the solar charging controller 18 to the main controller 30. Therefore, when the SOC of the battery 11 recovers to the temporary upper limit through charging by the solar panel 17, the determination in step S16 becomes YES, and the prohibition on driving the motor is released (step S17). When step S17 is executed, the motor 14 becomes available for use. Although not shown in the figure, in conjunction with the processing of step S17, the main controller 30 displays a message on the instrument panel informing the user that the motor 14 has become available for use.

Figure 3 shows a flowchart of the process executed by the solar charging controller 18. The process from step S23 onwards in Figure 3 is executed when the motor is in a drive prohibited state (step S22: YES).

The solar charging controller 18 monitors the SOC of the battery 11 while the battery 11 is being charged by the solar panel 17 (steps S23: YES, S24). When the battery 11 is being charged by the solar panel 17 and the SOC of the battery 11 has recovered to the temporary upper limit, the solar charging controller 18 sends an external charging signal to the main controller 30 (steps S24: YES, S25).

In this way, when charging is performed using the solar panel 17, if the remaining power recovers to the temporary upper limit, the motor 14 becomes available for use. There is no inconsistency between the drive prohibition process and the solar panel charging process as described above.

After the main controller 30 releases the prohibition on driving the motor 14 in step S17, it may return the upper limit value to the value before it was updated with the temporary upper limit value (the upper limit candidate value selected by the user), and continue charging using the solar panel 17.

The solar charging controller 18 operates on the power generated by the solar panel 17. Therefore, even if the remaining power of the accessory battery (not shown) is low, the solar charging controller 18 can operate as long as the solar panel 17 is generating power. The same applies to the main controller 30.

The above processing by the main controller 30, the external charging controller 21, and the solar charging controller 18 ensures consistency between the processing when charging the battery 11 with the external power source 90 and the processing when charging the battery 11 with the solar panel 17.

Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful.

10: Electric vehicle 11: Battery 12: System relay 13: Inverter 14: Motor 15: Differential gear 16: Drive wheel 17: Solar panel 18: Solar charging controller 19: Voltage sensor 20: Power receiving socket 21: External charging controller 22: Plug detector 30: Main controller 31: Input device 90: External power supply 91: Power supply plug

Claims (1)

A battery that supplies power to the driving motor;
a power receiving socket for connecting a power supply plug of an external power source;
a solar panel connected to the battery;
a main controller that inhibits the motor from being driven when the remaining power of the battery falls below a predetermined lower limit;
an external charging controller that transmits an external charging signal to the main controller when it detects that a current flows from the power receiving socket to the battery;
a solar charging controller for controlling charging of the battery by the solar panel;
Equipped with
The main controller includes:
(1) setting an upper limit candidate value selected by a user from among a plurality of upper limit candidate values as the upper limit value;
(2) when the battery is being charged by the external power source, stopping charging by the external power source when the remaining power amount reaches the upper limit value;
(3) canceling the inhibition of driving of the motor under the conditions that the external charging signal has been received and that the remaining power amount has recovered to an upper limit value that is greater than the lower limit value;
(4) when it is detected that the power supply plug is inserted into the power receiving socket in a state where the remaining power amount has reached the upper limit value, charging by the solar panel is prohibited;
(5) when charging of the battery by the solar panel is started, the upper limit value is updated with a predetermined temporary upper limit value that is equal to or less than a minimum upper limit candidate value among the upper limit candidate values;
The solar charging controller charges the battery by the solar panel, and when the remaining power reaches the temporary upper limit, transmits the external charging signal to the main controller.
Electric car.

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