JP2020129952A - vehicle - Google Patents

Abstract

To achieve both protection of a power storage device and securing an opportunity for external charging.SOLUTION: In a vehicle including: a power storage device; and a control device for permitting execution of external charging when external charging is instructed to charge the power storage device using power from an external power source, and a voltage of the power storage device is less than or equal to a permitted charging voltage, and for not permitting external charging when the voltage of the power storage device is higher than the permitted charging voltage, the control device sets a charging permission voltage based on an internal resistance of the power storage device and/or a period from shipment.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle.

Conventionally, as a vehicle of this type, when a secondary battery is charged using electric power from a power supply circuit, a predetermined current is supplied to perform constant current charging until the closed circuit voltage of the secondary battery reaches a predetermined voltage. There has been proposed a charging device for a secondary battery that performs constant voltage charging with a predetermined voltage after performing (see, for example, Patent Document 1).

JP, 2005-171275, A

In the above-mentioned vehicle, when execution of external charging for charging the secondary battery using electric power from the power supply circuit is instructed, execution of external charging is permitted when the voltage of the secondary battery is equal to or lower than the charge permission voltage, It is considered that when the voltage of the secondary battery is higher than the charge permission voltage, execution of external charging is not permitted. This is because when the secondary battery is charged from a relatively high voltage that is not fully charged, the internal resistance of the secondary battery may cause a sudden increase in the voltage of the secondary battery and an overvoltage. At this time, if the charging permission voltage is uniformly lowered to protect the secondary battery, the opportunity for external charging is limited, which may give the user a feeling of discomfort or shorten the next mileage. is there.

The main object of the vehicle of the present invention is to both protect the power storage device and secure an opportunity for external charging.

The vehicle of the present invention employs the following means in order to achieve the above-mentioned main object.

The vehicle of the present invention is
A power storage device,
When execution of external charging for charging the power storage device using electric power from an external power source is instructed, execution of the external charge is permitted when the voltage of the power storage device is equal to or lower than the charge permission voltage, and the voltage of the power storage device is A control device that does not permit execution of the external charging when is higher than the charge permission voltage,
A vehicle comprising:
The control device sets the charge permission voltage based on an internal resistance of the power storage device and/or a period from shipment.
That is the summary.

In the vehicle of the present invention, when execution of external charging for charging the power storage device using electric power from the external power source is instructed, execution of external charging is permitted when the voltage of the power storage device is equal to or lower than the charge permission voltage, and When the voltage of the device is higher than the charging permission voltage, execution of external charging is not permitted. At this time, the charge permission voltage is set based on the internal resistance of the power storage device and/or the period from shipment. As a result, as compared with the case where the charge permission voltage is uniformly lowered relatively irrespective of the internal resistance of the power storage device and the period from the shipment, external charging of the secondary battery is performed according to the internal resistance of the secondary battery and the period from the shipment. Opportunity can be secured. As a result, both protection of the power storage device and securing of an opportunity for external charging can be achieved.

In such a vehicle of the present invention, the control device sets the internal resistance of the power storage device to be higher when it is large and/or when the period from the shipment is short than when it is long. The charge permission voltage may be set to be higher. In this way, the charge permission voltage can be set more appropriately.

Further, in the vehicle of the present invention, the control device may set the charging permission voltage so that the temperature becomes higher when the temperature of the power storage device is higher than when the temperature is low. In this way, the charge permission voltage can be set more appropriately.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 as one Example of this invention. 6 is a flowchart showing an example of a processing routine executed by the electronic control unit 50. It is explanatory drawing which shows an example of the map for charge permission voltage setting.

Next, modes for carrying out the present invention will be described using examples.

FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 as an embodiment of the present invention. As illustrated, the electric vehicle 20 of the embodiment includes a motor 32, an inverter 34, a battery 36, a charger 40, a system main relay SMR, a charging relay CHR, and an electronic control unit 50.

The motor 32 is configured as, for example, a synchronous generator motor, and has a rotor connected to a drive shaft 26 that is connected to the drive wheels 22a and 22b via a differential gear 24. The inverter 34 is used to drive the motor 32 and is connected to the power line 38. The motor 32 is rotationally driven by the electronic control unit 50 controlling switching of a plurality of switching elements (not shown) of the inverter 34. The battery 36 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and is connected to the inverter 34 via the power line 38 as described above.

The charger 40 is connected to the power line 38, and has a vehicle side connector 42 connected to the charger 40 and a power source side connector 92 connected to the external power source 90 when the system is off at a charging point such as a home or a charging station. Is connected, the battery 36 is configured to be externally charged by using the electric power from the external power source 90. The charger 40 is controlled by the electronic control unit 50.

The system main relay SMR is provided between the inverter 34 and the battery 36 in the power line 38, and is on/off controlled by the electronic control unit 50 to connect and disconnect the inverter 34 side and the battery 36 side. Do.

The charging relay CHR is provided between the battery 36 and the charger 40 in the power line 38, and is on/off controlled by the electronic control unit 50, so that the battery 36 and the charger 40 are connected and disconnected. Do.

Although not shown, the electronic control unit 50 is configured as a microprocessor centered on a CPU, and includes, in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, and an input/output port. Signals from various sensors are input to the electronic control unit 50 via input ports. The signal input to the electronic control unit 50 is, for example, the rotational position of the rotor of the motor 32 from a rotational position sensor that detects the rotational position of the rotor of the motor 32, or the voltage attached between the terminals of the battery 36. The voltage Vb of the battery 36 from the sensor 36a, the current Ib of the battery 36 from the current sensor 36b attached to the output terminal of the battery 36 (a positive value when the battery 36 is charged), the temperature sensor attached to the battery 36 The temperature Tb of the battery 36 from 36c can be mentioned. Further, a connection detection signal from the connection detection sensor 43 which is attached to the vehicle side connector 42 and detects the connection between the vehicle side connector 42 and the power source side connector 92 can be cited. Furthermore, the ignition signal from the ignition switch, the shift position SP from the shift position sensor, the accelerator opening degree from the accelerator pedal position sensor, the brake pedal position from the brake pedal position sensor, and the vehicle speed from the vehicle speed sensor can also be mentioned.

Various control signals are output from the electronic control unit 50 via the output ports. Examples of the signal output from the electronic control unit 50 include a control signal to the inverter 34, a control signal to the charger 40, a control signal to the system main relay SMR, and a control signal to the charging relay CHR. it can.

The electronic control unit 50 calculates the storage ratio SOC of the battery 36 based on the integrated value of the current Ib of the battery 36 from the current sensor 36b. Further, the electronic control unit 50 estimates the internal resistance Rb of the battery 36 by using a plurality of sets of the voltage Vb of the battery 36 from the voltage sensor 36a and the current Ib of the battery 36 from the current sensor 36b. Further, during external charging, the electronic control unit 50 calculates the charging power Pch of the battery 36 as the product of the voltage Vb of the battery 36 from the voltage sensor 36a and the current Ib of the battery 36 from the current sensor 36b. There is.

Next, the operation of the electric vehicle 20 of the embodiment configured as described above, particularly, the vehicle side connector 42 and the power source side connector 92 are connected at a charging point such as a home or a charging station when the system is off, and an instruction to execute external charging is given. The operation performed will be described. FIG. 2 is a flowchart showing an example of a processing routine executed by the electronic control unit 50 at this time. The instruction to execute external charging is given by, for example, a user operating a charging start switch (not shown) provided in a charging stand having an external power source 90.

When the processing routine of FIG. 2 is executed, the electronic control unit 50 first inputs data such as the voltage Vb of the battery 36, the temperature Tb, and the internal resistance Rb (step S100). Here, as the voltage Vb of the battery 36, the value detected by the voltage sensor 36a is input. As the temperature Tb of the battery 36, the value detected by the temperature sensor 36c is input. As the internal resistance Rb of the battery 36, the value estimated by the above method is input.

When the data is input in this way, the charge permission voltage Vth for determining whether or not to permit charging of the battery 36 is set based on the input temperature Tb and internal resistance Rb of the battery 36 (step S110). Here, in the embodiment, the charging permission voltage Vth is stored in a ROM (not shown) as a charging permission voltage setting map in which a relationship between the temperature Tb of the battery 36 and the internal resistance Rb and the charging permission voltage Vth is predetermined. Given the temperature Tb and the internal resistance Rb of the battery 36, the corresponding charging permission voltage Vth is derived from this map and set. FIG. 3 is an explanatory diagram showing an example of the charge permission voltage setting map. As shown in FIG. 3, the charge permission voltage Vth is set to be higher as the internal resistance Rb of the battery 36 is smaller and higher as the temperature Tb of the battery 36 is higher. The reason for this will be described later.

When the charging permission voltage Vth is set in this manner, the voltage Vb of the battery 36 is compared with the charging permission voltage Vth (step S120). Then, when the voltage Vb of the battery 36 is equal to or lower than the charging permission voltage Vth, execution of external charging is permitted (step S130), and this routine is ended. When the execution of the external charging is permitted in this way, the charging relay CHR is turned on and the charger 40 is controlled so that the battery 36 is charged by using the electric power from the external power source 90. Then, when the voltage Vb of the battery 36 reaches the charging end voltage Vth2 which is higher than the charging permission voltage Vth or more, the driving of the charger 40 is stopped.

When the voltage Vb of the battery 36 is higher than the charging permission voltage Vth in step S120, this routine is terminated without permitting execution of external charging. As a result, it is possible to prevent the voltage Vb of the battery 36 from rapidly increasing and prevent the battery 36 from reaching an overvoltage. Further, it is possible to suppress the deterioration of the battery due to the increase in the storage ratio SOC of the battery 36.

Here, the reason why the charging permission voltage Vth is set to the tendency shown in FIG. 3 will be described. When the battery 36 is charged from a relatively high voltage that is not fully charged, the internal resistance Rb of the battery 36 may cause the voltage Vb of the battery 36 to rapidly increase and reach an overvoltage. Therefore, although it is conceivable to use the charge permission voltage Vth to determine whether or not to perform the external charge, if the charge permission voltage Vth is relatively low uniformly to protect the battery 36, the opportunity of the external charge is increased. There is a possibility that the user will be restricted and the user may feel uncomfortable or that the next possible travel distance will be shortened. According to experiments and analysis, the inventors have a tendency that the larger the internal resistance Rb of the battery 36, the more rapidly the voltage Vb of the battery 36 increases during external charging (in other words, the smaller the internal resistance Rb of the battery 36, the more external charging occurs. It has been found that the voltage Vb of the battery 36 is unlikely to rise sharply. It is also known that the lower the temperature Tb of the battery 36, the larger the internal resistance Rb of the battery 36. In the embodiment, based on the above, the charging permission voltage Vth is set so that it becomes higher as the internal resistance Rb of the battery 36 becomes smaller and becomes higher as the temperature Tb of the battery 36 becomes higher. Thereby, when the internal resistance Rb of the battery 36 is small or when the temperature Tb of the battery 36 is high, it is possible to protect the battery 36 and secure more opportunities for external charging. As a result, both protection of the battery 36 and securing of an opportunity for external charging can be achieved.

In the electric vehicle 20 of the embodiment described above, when the execution of the external charging is instructed, the execution of the external charging is permitted and the voltage Vb of the battery 36 is charged when the voltage Vb of the battery 36 is equal to or lower than the charge permission voltage Vth. When the voltage is higher than the permission voltage Vth, execution of external charging is not permitted. At this time, the charge permission voltage Vth is set such that it becomes higher as the internal resistance Rb of the battery 36 becomes smaller and becomes higher as the temperature Tb of the battery 36 becomes higher. This makes it possible to achieve both protection of the battery 36 and securing of an opportunity for external charging.

In the electric vehicle 20 of the embodiment, the charging permission voltage Vth is set based on the temperature Tb of the battery 36 and the internal resistance Rb. However, the charging permission voltage Vth may be set based only on the internal resistance Rb of the battery 36. Further, the charge permission voltage Vth may be set based on the period from shipment, or the charge permission voltage Vth may be set based on the period from shipment and the temperature Tb of the battery 36. The charging permission voltage Vth may be set based on the internal resistance Rb of the battery 36 and the period from shipment, or the charging permission voltage Vth may be set based on the internal resistance Rb and temperature Tb of the battery 36 and the period from shipment. It may be done. When considering the period from shipping, the charging permission voltage Vth may be set so that the shorter the period from shipping, the higher the charging permission voltage Vth. This is because the internal resistance Rb of the battery 36 is considered to increase as the period from shipment increases.

Correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the battery 36 corresponds to a “power storage device” and the electronic control unit 50 corresponds to a “control device”.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is that the embodiment implements the invention described in the section of means for solving the problem. This is an example for specifically explaining the mode for carrying out the invention, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problem should be made based on the description in that column, and the embodiment is the invention of the invention described in the column of means for solving the problem. This is just a specific example.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments, and various embodiments are possible without departing from the scope of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICABILITY The present invention can be used in the vehicle manufacturing industry and the like.

20 electric vehicle, 22a, 22b drive wheels, 24 differential gear, 26 drive shaft, 32 motor, 34 inverter, 36 battery, 36a voltage sensor, 36b current sensor, 36c temperature sensor, 38 power line, 40 charger, 42 vehicle side Connector, 43 connection detection sensor, 50 electronic control unit, 90 external power supply, 92 power supply side connector.

Claims (1)

A power storage device,
When execution of external charging for charging the power storage device using electric power from an external power source is instructed, execution of the external charge is permitted when the voltage of the power storage device is equal to or lower than the charge permission voltage, and the voltage of the power storage device is A control device that does not permit execution of the external charging when is higher than the charge permission voltage,
A vehicle comprising:
The control device sets the charge permission voltage based on an internal resistance of the power storage device and/or a period from shipment.
vehicle.

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