JP7251415B2 - charging controller - Google Patents

Description

The present invention relates to a charging control device that controls charging of a battery mounted on a vehicle.

Some charging control devices terminate charging when the difference between the target charging amount and the estimated current charging capacity becomes a fixed value or less in order to optimize the battery charging amount according to the vehicle usage conditions. . As a related technology, there is Patent Document 1.

By the way, the estimated value of the charging capacity of the battery is a value obtained from the current flowing through the battery during charging and the voltage of the battery. However, there is a possibility that the integrated value of the current flowing through the battery being charged may include the measurement error of the ammeter. Similarly, battery voltage measurements may include voltmeter measurement errors.

Therefore, in the charging control device, when charging is performed using the estimated value of the charge capacity, due to the influence of the error included in the estimated value, even if the estimated value does not exceed the threshold value corresponding to the overcharged state of the battery. Regardless, there is a risk that the true charge capacity will exceed the threshold and the battery will deteriorate. Similarly, there is a risk that the charging capacity will be insufficient due to the influence of the error.

JP 2013-051809 A

An object of one aspect of the present invention is to optimize the charge amount of a battery according to the vehicle usage conditions.

A charging control device, which is one aspect of the present invention, is a charging control device for controlling charging of a battery mounted on a vehicle, and includes a storage unit for storing a charging voltage and an end current, and and a changing unit for changing at least one of the charging voltage and the end current, and the current flowing through the battery when the voltage of the battery becomes equal to or higher than the charging voltage stored in the storage unit when the current flowing through the battery is kept constant. is gradually reduced, and when the current flowing through the battery becomes equal to or less than the end current stored in the storage unit, the current flowing through the battery is made zero.

As a result, when the charge capacity of the battery can be relatively small, such as when the amount of vehicle usage per unit time is small, the end current stored in the storage unit is changed to the first end current that is larger than the reference end current. Alternatively, the charging voltage stored in the storage unit is changed to a first charging voltage that is lower than the reference charging voltage, or the charging voltage stored in the storage unit is changed to the first charging voltage and stored By changing the end current stored in the unit to the first end current, the charge capacity of the battery after charging can be reduced, and deterioration of the battery can be suppressed. In addition, since charging is controlled using the voltage of the battery being charged and the current flowing through the battery, it is possible to control charging using the charge capacity estimated from the integrated value of the current flowing through the battery being charged. In comparison, it is possible to charge without being affected by the error in the charge capacity estimate, charge to the desired charge, and the true charge capacity exceeds the threshold corresponding to the overcharge condition of the battery. It is possible to reduce the deterioration of the battery due to exceeding. Similarly, it is possible to avoid insufficient charging capacity due to insufficient charging amount due to the error. In other words, it is possible to optimize the amount of charge in the battery according to the usage conditions of the vehicle.

Further, when the usage amount of the vehicle per unit time is equal to or less than the first threshold value and is greater than a second threshold value which is smaller than the first threshold value, the change unit changes the end current stored in the storage unit to a second threshold value. 1, and the vehicle usage per unit time is less than or equal to the second threshold and greater than or equal to a third threshold that is smaller than the second threshold, the charging voltage stored in the storage unit is changed to the first charging voltage, and if the usage amount of the vehicle per unit time is equal to or less than the third threshold, the charging voltage stored in the storage unit is changed to the first charging voltage and The stored end current may be changed to the first end current.

As a result, when the time available for charging the vehicle is short and when the vehicle is used immediately after charging is finished, the end current stored in the storage unit is changed to the first end current. Since the decrease in the charge capacity of the battery after charging can be suppressed, it is possible to extend the life of the battery while ensuring the charge capacity of the battery. In addition, when the time available for charging the vehicle is short and the usage amount of the vehicle per unit time is relatively small, or when the vehicle is left for a relatively long time after charging is completed, the By changing the current charging voltage to the first charging voltage, the charge capacity of the battery after charging can be reduced, so that the life of the battery can be extended. By the way, by changing the charging voltage, it is possible to secure the accuracy of the charging amount, and by changing the charging current, it is possible to secure the charging amount per hour. Therefore, when the amount of vehicle usage per unit time is smaller or when the vehicle is left for a longer period of time after charging is completed, the charging voltage stored in the storage unit is changed to the first charging voltage and By combining the respective methods so as to change the stored end current to the first end current, it is possible to both extend the life of the battery and secure the optimum charge capacity.

The change unit changes the end current stored in the storage unit to a second end current that is larger than the reference end current and smaller than the first end current, according to the temperature of the battery or the degree of deterioration of the battery. Alternatively, the charging voltage stored in the storage unit is changed to a second charging voltage that is lower than the reference charging voltage and higher than the first charging voltage, or the charging voltage stored in the storage unit is changed to The end current stored in the storage section may be changed to the second end current while changing to the second charging voltage.

As a result, even if the internal resistance of the battery increases and the voltage of the battery during charging increases due to a decrease in battery temperature or deterioration of the battery, it is possible to suppress a decrease in the amount of charge in the battery. It is possible to suppress the decrease in the travel distance and operating time of the vehicle due to the temperature rise of the battery and deterioration of the battery.

A charging control device, which is one aspect of the present invention, is a charging control device for controlling charging of a battery mounted on a vehicle, wherein a storage unit for storing a charging voltage, and a storage unit for storing a changing unit for changing the charging voltage; and a charging control unit for reducing the current flowing through the battery to zero when the voltage of the battery becomes equal to or higher than the charging voltage stored in the storage unit while the current flowing through the battery is kept constant. Prepare.

As a result, when the charging capacity of the battery can be relatively small, such as when the amount of vehicle usage per unit time is small, the charging voltage stored in the storage unit is changed to the first charging voltage that is lower than the reference charging voltage. By doing so, the charge amount of the battery after charging can be reduced, and deterioration of the battery can be suppressed. In addition, since it is configured to control charging using the voltage of the battery being charged, the ammeter is less effective than the case of controlling charging using the charge capacity estimated from the integrated value of the current flowing through the battery being charged. The charge capacity of the battery after charging can be approximated to the true charge capacity by eliminating the influence of measurement errors, and the true charge capacity exceeds the threshold corresponding to the overcharged state of the battery, resulting in deterioration of the battery. can be reduced. That is, it is possible to optimize the charging capacity of the battery according to the vehicle usage conditions.

The changing unit changes the charging voltage stored in the storage unit to a second charging voltage that is lower than the reference charging voltage and higher than the first charging voltage, according to the temperature of the battery or the degree of deterioration of the battery. You may make it

As a result, even if the internal resistance of the battery rises due to a rise in battery temperature or deterioration of the battery and the voltage of the battery during charging rises, the voltage of the battery does not easily exceed the charging voltage stored in the storage unit. Therefore, it is possible to suppress a decrease in the amount of charge in the battery, and it is possible to suppress a decrease in the travel distance and travel time of the vehicle due to an increase in battery temperature and deterioration of the battery.

According to the present invention, it is possible to optimize the charging amount of the battery according to the usage condition of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of a vehicle and a charger containing the charge control apparatus of embodiment. It is a figure which shows an example of a screen. 4 is a flow chart showing an example of the operation of a control unit; FIG. 3 is a diagram showing an example of the current flowing through the battery and the voltage of the battery; FIG. 3 is a diagram showing an example of the current flowing through the battery and the voltage of the battery;

Embodiments will be described in detail below with reference to the drawings.
FIG. 1 is a diagram showing an example of a vehicle and a charger including a charging control device of an embodiment.

A vehicle Ve shown in FIG. 1 is an electric forklift, an electric towing tractor, an electric vehicle, or the like, and includes a load Lo, a storage unit 1, a control unit 2, and a battery pack BP.

The load Lo is an inverter circuit or the like that drives a traveling motor or a cargo handling motor.
The storage unit 1 is composed of a RAM (Random Access Memory), a ROM (Read Only Memory), or the like.

The control unit 2 is configured by a CPU (Central Processing Unit) or a programmable device (FPGA (Field Programmable Gate Array) or PLD (Programmable Logic Device)), and controls the operation of the load Lo and the overall operation of the vehicle Ve. .

Charger Ch includes power converter 3 , storage 4 , and controller 5 .
The power conversion unit 3 converts AC power supplied from the system power supply P into predetermined power, and supplies the power to the battery pack BP.

The storage unit 4 is configured by RAM, ROM, or the like.
The control unit 5 is configured by a CPU, a programmable device, or the like, and controls the operation of the power conversion unit 3 based on instructions from the user and instructions from the vehicle Ve.

The battery pack BP includes a battery B, a voltmeter 6, an ammeter 7, a thermometer 8, a switch SW1, a switch SW2, a storage section 9, and a control section .

Battery B is composed of one or more secondary batteries such as lithium-ion batteries or nickel-metal hydride batteries, and supplies power to load Lo. Further, when electric power is supplied to the battery B from the charger Ch provided outside the vehicle Ve, that is, when the current flows from the charger Ch to the battery B, the battery B is charged and the voltage of the battery B increases. Rise.

The voltmeter 6 is composed of a voltage dividing resistor, an operational amplifier, etc., measures the voltage of the battery B, and sends the measured voltage to the control unit 10 .

The ammeter 7 is composed of a Hall element, a shunt resistor, etc., measures the current flowing through the battery B, and sends the measured current to the control unit 10 .

The thermometer 8 is composed of a thermistor or the like, measures the temperature of the battery B, and sends the measured temperature to the control unit 10 .

Each of the switches SW1 and SW2 is configured by a semiconductor relay (for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor)) or an electromagnetic relay. One terminal of the switch SW1 is connected to the negative terminal of the battery B, and the other terminal of the switch SW1 is connected to the negative terminal of the charger Ch. One terminal of the switch SW2 is connected to the negative terminal of the battery B, and the other terminal of the switch SW2 is connected to the negative terminal of the load Lo. When the switch SW1 is turned on and the switch SW2 is turned off, power can be supplied to the battery B from the charger Ch. When the switch SW1 is cut off and the switch SW2 is turned on, the battery B can supply power to the load Lo.

The storage unit 9 is configured by RAM, ROM, or the like, and stores a charging voltage and an end current, which will be described later. It is assumed that the storage unit 9 stores the reference charging voltage Vr and the reference termination current Ir as initial values.

The control unit 10 includes a CPU, a programmable device, or the like, includes a change unit 11 and a charging control unit 12, and controls operations of the switches SW1 and SW2. Also, the control unit 10 communicates with the control unit 2 and the control unit 5 . Note that the change unit 11 and the charge control unit 12 are implemented by the CPU or a programmable device executing the program stored in the storage unit 9 . For example, the charging control device includes a storage unit 9 , a changing unit 11 of the control unit 10 , and a charging control unit 12 of the control unit 10 . Note that the changing unit 11 and the charging control unit 12 may be provided in the control unit 2 mounted on the vehicle Ve. In such a configuration, the charging control device is composed of the storage unit 1 , the changing unit 11 of the control unit 2 , and the charging control unit 12 of the control unit 2 . Further, the changing unit 11 and the charging control unit 12 may be provided in the control unit 5 mounted on the charger Ch. In such a configuration, the charging control device is composed of the storage unit 4 , the changing unit 11 of the control unit 5 , and the charging control unit 12 of the control unit 5 .

The changing unit 11 changes at least one of the charging voltage and the end current stored in the storage unit 9 . After changing at least one of the charging voltage and the end current stored in the storage unit 9, the changing unit 11 further changes the temperature of the battery B or the degree of deterioration of the battery B (internal resistance of the battery B, full charge capacity, etc.), at least one of the charging voltage and the end current stored in the storage unit 9 is changed.

The charging control unit 12 uses the charging voltage and the end current stored in the storage unit 9 to perform constant current charging control and constant voltage charging control.

First, when the constant current charging control is started, the charging control unit 12 instructs the control unit 5 of the charger Ch so that the current measured by the ammeter 7 becomes constant. Control unit 5 controls the operation of power conversion unit 3 according to the instruction so that the current flowing from charger Ch to battery B is constant. When a constant current flows through the battery B, the battery B is charged and the voltage of the battery B gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the charging voltage stored in the storage unit 9, the charging control unit 12 ends constant current charging control and starts constant voltage charging control. When the charging control unit 14 starts the constant voltage charging control, the current flowing from the charger Ch to the battery B gradually decreases while maintaining the state where the voltage of the battery B is equal to or higher than the charging voltage stored in the storage unit 9. The controller 5 is instructed to do so. According to the instruction, the control unit 5 maintains the voltage of the battery B at the charging voltage stored in the storage unit 9 or higher, and adjusts the power so that the current flowing from the charger Ch to the battery B gradually decreases. It controls the operation of the conversion unit 3 . For example, during constant voltage charging control, the control unit 5 increases the current measured by the ammeter 7 by a predetermined value each time the voltage measured by the voltmeter 6 exceeds the charging voltage stored in the storage unit 9. It may be configured to control the operation of the power conversion unit 3 so as to decrease.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current stored in the storage unit 9, the charging control unit 12 controls the control unit 5 so that the current flowing from the charger Ch to the battery B becomes zero. to terminate the constant voltage charging control.

<Example 1 of change unit 11>
The change unit 11 changes the storage unit 9 when the charge capacity of the battery B may be relatively small, such as when the amount of use of the vehicle Ve per unit time (travel distance or travel time per unit time of the vehicle Ve) is small. to an end current I1 (first end current) higher than the reference end current Ir, or change the charging voltage stored in the storage unit 9 to a charging voltage V1 lower than the reference charging voltage Vr. (first charging voltage), or the charging voltage stored in the storage unit 9 is changed to the charging voltage V1 and the end current stored in the storage unit 9 is changed to the end current I1. As a result, since the charge capacity of the battery B after charging can be reduced, the deterioration of the battery B can be suppressed, and the service life of the battery B can be extended.

<Embodiment 2 of Change Unit 11>
The changing unit 11 changes the end current stored in the storage unit 9 to the end current I1 when the usage amount of the vehicle Ve per unit time is equal to or less than the first threshold and is greater than the second threshold. , when the usage amount per unit time of the vehicle Ve is equal to or less than the second threshold value and is greater than the third threshold value, the charging voltage stored in the storage unit 9 is changed to the charging voltage V1, and the vehicle Ve When the usage amount per unit time is equal to or less than the third threshold, the charging voltage stored in the storage unit 9 is changed to the charging voltage V1 and the end current stored in the storage unit 9 is changed to the end current I1. do. Note that the first threshold>the second threshold>the third threshold. As a result, when the vehicle Ve is an industrial vehicle such as a forklift, when the battery B is charged in a relatively short charging time, and when the vehicle Ve is used immediately after charging is completed, the storage unit 9 is changed to the end current I1, it is possible to suppress the decrease in the charge capacity of the battery B after charging. It is also possible to extend the service life. In addition, when the vehicle Ve is an industrial vehicle such as a forklift, and when the usage amount of the vehicle Ve per unit time is relatively small, or when the vehicle Ve is left for a relatively long time after charging is completed, the storage unit 9 By changing the charging voltage stored in , to the charging voltage V1, the charging capacity of the battery B after charging can be reduced, so that the service life of the battery B can be extended. In addition, when the vehicle Ve is an industrial vehicle such as a forklift, and when the usage amount of the vehicle Ve per unit time is even smaller, or when the vehicle Ve is left for a longer time after charging is finished, the storage unit 9 stores By changing the current charging voltage to the charging voltage V1 and changing the end current stored in the storage unit 9 to the end current I1, the charge capacity of the battery B after charging can be further reduced. The life of battery B can be further extended.

<Embodiment 3 of Change Unit 11>
The changing unit 11 receives a request from a user who wants to extend the life of the battery B while charging the battery B in a relatively short time or a user who wants to extend the life of the battery B because the amount of usage per unit time of the vehicle Ve is relatively small. According to the instruction, the end current stored in the storage unit 9 is changed to the end current I1, the charging voltage stored in the storage unit 9 is changed to the charging voltage V1, or the The current charging voltage is changed to the charging voltage V1, and the end current stored in the storage unit 9 is changed to the end current I1.

Here, FIGS. 2A and 2B are diagrams showing examples of screens displayed on a display unit (touch panel, etc.) (not shown) provided in the battery pack Bp, the vehicle Ve, or the charger Ch. be.

Buttons B1 to B4 are provided on the screen D1 shown in FIG. 2(a).
When the user presses the button B1 and inputs an instruction to the effect that the "normal mode" is selected to the changing unit 11, the changing unit 11 does not change the charging voltage and the end current stored in the storage unit 9. . That is, when the "normal mode" is selected by the user, the charging voltage and the end current stored in the storage unit 9 remain unchanged at the reference charging voltage Vr and the reference end current Ir.

When the user presses the button B2 to input an instruction to the effect that the "supplementary charging mode" has been selected to the changing unit 11, the changing unit 11 does not change the charging voltage stored in the storage unit 9 and stores it. The end current stored in the section 9 is changed to the end current I1. That is, when the "supplementary charging mode" is selected by the user, the charging voltage stored in the storage unit 9 remains unchanged at the reference charging voltage Vr, and the end current stored in the storage unit 9 increases.

When the user presses the button B3 and inputs an instruction to the effect that the "life extension mode A" is selected to the changing unit 11, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1. The termination current stored in the storage unit 9 is not changed when the current is changed. That is, when the user selects the "life extension mode A", the charging voltage stored in the storage unit 9 decreases and the end current stored in the storage unit 9 remains the reference end current Ir.

When the user presses the button B4 and inputs an instruction to the effect that the "life extension mode B" is selected to the changing unit 11, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1. Along with the change, the end current stored in the storage unit 9 is changed to the end current I1. That is, when the user selects the "life extension mode B", the charging voltage stored in the storage unit 9 decreases and the termination current stored in the storage unit 9 increases.

The screen D2 shown in FIG. 2(b) includes buttons Bv1 to Bv8 for changing the charging voltage stored in the storage unit 9 in eight steps, and the end current stored in the storage unit 9 in eight steps. Buttons Bi1 to Bi8 are provided for changing. The button Bv1 corresponds to the charging voltage V1, and the button Bv8 corresponds to the reference charging voltage Vr. Also, the charging voltage corresponding to each button increases in the order of buttons Bv2, Bv3, Bv4, Bv5, Bv6, and Bv7. Further, the button Bi1 corresponds to the reference end current Ir, and the button Bi8 corresponds to the end current I1. Also, the termination current corresponding to each button increases in the order of buttons Bi2, Bi3, Bi4, Bi5, Bi6, and Bi7.

When the user presses the button Bv8 and the button Bi1, the changing unit 11 does not change the charging voltage and the end current stored in the storage unit 9. FIG. That is, when the user presses the button Bv8 and the button Bi1, the charging voltage and the end current stored in the storage unit 9 remain unchanged at the reference charging voltage Vr and the reference end current Ir.

When the user presses the button Bv8 and the button Bi8, the changing unit 11 does not change the charging voltage stored in the storage unit 9 and changes the end current stored in the storage unit 9 to the end current I1. do. That is, when the user presses the button Bv8 and the button Bi8, the charging voltage stored in the storage unit 9 remains the reference charging voltage Vr, and the end current stored in the storage unit 9 increases. Become.

When the user presses the button Bv1 and the button Bi1, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1 and changes the end current stored in the storage unit 9. do not. That is, when the user presses the button Bv1 and the button Bi1, the charging voltage stored in the storage unit 9 decreases and the end current stored in the storage unit 9 is changed to the reference end current Ir. not.

When the user presses the button Bv1 and the button Bi8, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1 and terminates the end current stored in the storage unit 9. Change to current I1. That is, when the user presses the button Bv1 and the button Bi8, the charging voltage stored in the storage unit 9 decreases and the end current stored in the storage unit 9 increases.

<Embodiment 4 of Change Unit 11>
The change unit 11 changes the end current stored in the storage unit 9 to a end current I2 (second end current). Further, the changing unit 11 changes the charging voltage stored in the storage unit 9 according to the temperature of the battery B or the degree of deterioration of the battery B to a charging voltage V2 ( second charging voltage). Further, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V2 according to the temperature of the battery B or the degree of deterioration of the battery B, and changes the ending current stored in the storage unit 9 to V2. Change to end current I2. As a result, even if the temperature of the battery B rises or the battery B deteriorates, the internal resistance of the battery B increases and the voltage of the battery B during charging increases, but the charge capacity of the battery B is prevented from decreasing. Therefore, it is possible to suppress the decrease in the travelable distance of the vehicle Ve due to the temperature rise of the battery B and the deterioration of the battery B.

FIG. 3 is a flow chart showing an example of the operation of the control unit 10. As shown in FIG.
First, the changing unit 11 of the control unit 10 changes the charging voltage and the end current stored in the storage unit 9 according to the usage status of the vehicle Ve, the instruction from the user, the temperature of the battery B, or the deterioration of the battery B. at least one of (step S1).

Next, the charging control section 12 of the control section 10 performs constant current charging control and constant voltage charging control using the charging voltage and end current stored in the storage section 9 (steps S2 to S5).

First, the charging control unit 12 starts constant current charging control (step S2), and when the voltage measured by the voltmeter 6 is lower than the charging voltage stored in the storage unit 9 (step S3: No), Constant current charging control is continued (step S2).

On the other hand, when the voltage measured by the voltmeter 6 is equal to or higher than the charging voltage stored in the storage unit 9 (step S3: Yes), the charging control unit 12 terminates constant-current charging control and performs constant-voltage charging. Control is started (step S4).

Next, when the current measured by the ammeter 7 is larger than the end current stored in the storage unit 9 (step S5: No), the charging control unit 12 continues constant voltage charging control (step S4).

On the other hand, when the current measured by the ammeter 7 is equal to or less than the end current stored in the storage unit 9 (step S5: Yes), the charging control unit 12 ends the constant current charging control.

Here, FIGS. 4 and 5 are diagrams showing an example of the current flowing through the battery B and the voltage of the battery B when the constant current charging control and the constant voltage charging control are performed.

FIG. 4A shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and ending current stored in the storage unit 9 are the reference charging voltage Vr and the reference ending current Ir. FIG. 4B shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I1. FIG. 4(c) shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the reference ending current Ir. FIG. 4D shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the ending current I1. The horizontal axis of the two-dimensional coordinates shown in FIGS. 4(a) to 4(d) indicates time, and the vertical axis indicates current or voltage. 4(a) to 4(d) show the current measured by the ammeter 7, and the broken lines shown in FIGS. 4(a) to 4(d) show the current measured by the voltmeter 6. voltage applied.

(When the charging voltage and end current stored in the storage unit 9 are the reference charging voltage Vr and the reference end current Ir)
First, the charging control unit 12 starts constant current charging control at time t0 in FIG. 4(a). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 reaches or exceeds the reference charging voltage Vr at time t3 in FIG. Then, the current measured by the ammeter 7 is gradually decreased.

Then, at time t6 in FIG. 4(a), when the current measured by the ammeter 7 becomes equal to or less than the reference end current Ir, the charging control unit 12 causes the current measured by the ammeter 7 to become zero, End voltage charge control.

(When the charging voltage and the end current stored in the storage unit 9 are the reference charging voltage Vr and the end current I1)
First, the charging control unit 12 starts constant current charging control at time t0 in FIG. 4(b). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the reference charging voltage Vr at time t3 in FIG. 4(b), the charging control unit 12 terminates constant current charging control and starts constant voltage charging control. Then, the current measured by the ammeter 7 is gradually decreased.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current I1 at time t4 in FIG. End charging control.

(When the charging voltage and end current stored in the storage unit 9 are the charging voltage V1 and the reference end current Ir)
First, the charging control unit 12 starts constant current charging control at time t0 in FIG. 4(c). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 reaches or exceeds the charging voltage V1 at time t1 in FIG. , the current measured by the ammeter 7 is gradually lowered.

Then, at time t5 in FIG. 4(c), when the current measured by the ammeter 7 becomes equal to or less than the reference end current Ir, the charging control unit 12 causes the current measured by the ammeter 7 to be zero, End voltage charge control.

(When the charging voltage and the end current stored in the storage unit 9 are the charging voltage V1 and the end current I1)
First, the charging control unit 12 starts constant current charging control at time t0 in FIG. 4(d). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 reaches or exceeds the charging voltage V1 at time t1 in FIG. , the current measured by the ammeter 7 is gradually lowered.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current I1 at time t2 in FIG. End charging control.

Note that time t0<time t1<time t2<time t3<time t4<time t5<time t6. Also, the period from time t3 to time t6 is assumed to be the same as the period from time t1 to time t5.

In this case, the integrated value (charge amount) of the current flowing through battery B during the period from time t3 to time t4 is smaller than the integrated value of the current flowing through battery B during the period from time t3 to time t6.

Therefore, the charge capacity of the battery B at the end of charging when the charging voltage and the end current stored in the storage unit 9 are the reference charging voltage Vr and the end current I1 are the charging voltage and the end current stored in the storage unit 9. It is smaller than the charge capacity of the battery B at the end of charging when the end current is the reference charging voltage Vr and the reference end current Ir.

That is, when only the end current is increased, the charge capacity of the battery B can be reduced and the life of the battery B can be extended compared to the case where the charging voltage and the end current are not changed.

Further, the integrated value of the current flowing through the battery B during the period from the time t3 to the time t6 and the integrated value of the current flowing through the battery B during the period from the time t1 to the time t5 are the same. The integrated value of the current flowing through battery B during the period from time t0 to time t1 is smaller than the integrated value of the current flowing through battery B during the period from time t0 to time t3.

Therefore, the charge capacity of the battery B at the end of charging when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V1 and the reference end current Ir are the charging voltage and the end current stored in the storage unit 9. It is smaller than the charge capacity of the battery B at the end of charging when the end current is the reference charging voltage Vr and the reference end current Ir.

That is, when only the charging voltage is reduced, the charging capacity of the battery B can be reduced and the life of the battery B can be extended compared to the case where the charging voltage and the termination current are not changed. When only the end current is increased, the charging time can be shortened while ensuring the charging capacity, compared to when only the charging voltage is decreased.

Further, the integrated value of the current flowing through battery B during the period from time t1 to time t2 is smaller than the integrated value of the current flowing through battery B during the period from time t1 to time t5.

Therefore, the charge capacity of the battery B at the end of charging when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V1 and the end current I1 are the charging voltage and the end current stored in the storage unit 9. It is smaller than the charge capacity of the battery B at the end of charging when the current is the charging voltage V1 and the reference end current Ir.

That is, when the charging voltage is decreased and the termination current is increased, the charging capacity of the battery B can be further reduced compared to when only the charging voltage is decreased. It is possible to secure both.

5A shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I2. FIG. 5B shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the reference ending current Ir. FIG. 5(c) shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the ending current I2. The horizontal axis of the two-dimensional coordinates shown in FIGS. 5(a) to 5(c) indicates time, and the vertical axis indicates current or voltage. 5(a) to 5(c) show the current measured by the ammeter 7, and the broken lines shown in FIGS. 5(a) to 5(c) show the current measured by the voltmeter 6. voltage applied.

(When the charging voltage and the end current stored in the storage unit 9 are the reference charging voltage Vr and the end current I2)
First, the charging control unit 12 starts constant current charging control at time t0 in FIG. 5(a). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the reference charging voltage Vr at time t3 in FIG. 5A, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. Then, the current measured by the ammeter 7 is gradually decreased.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current I2 at time t4' in FIG. End voltage charge control.

(When the charging voltage and end current stored in the storage unit 9 are the charging voltage V2 and the reference end current Ir)
First, the charging control unit 12 starts constant current charging control at time t0 in FIG. 5(b). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the charging voltage V2 at time t1' in FIG. Then, the current flowing through the battery B is gradually decreased.

Then, when the current measured by the ammeter 7 becomes equal to or less than the reference end current Ir at time t5' in FIG. End control.

(When the charging voltage and the end current stored in the storage unit 9 are the charging voltage V2 and the end current I2)
First, the charging control unit 12 starts constant current charging control at time t0 in FIG. 5(c). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the charging voltage V2 at time t11 in FIG. 5(c), the charging control unit 12 terminates constant current charging control and starts constant voltage charging control. , the current flowing through battery B is gradually reduced.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current I2 at time t22 in FIG. End charging control.

It is assumed that the period from time t3 to time t4' shown in FIG. 5(a) is longer than the period from time t3 to time t4 shown in FIG. 4(b). Also, the period from time t0 to time t1' shown in FIG. 5(b) is assumed to be longer than the period from time t0 to time t1 shown in FIG. 4(c). It is also assumed that the period from time t1' to time t5' shown in FIG. 5(b) is the same as the period from time t1 to time t5 shown in FIG. 4(c). Also, the period from time t0 to time t11 shown in FIG. 5(c) is assumed to be longer than the period from time t0 to time t1 shown in FIG. 4(d). Also, the period from time t11 to time t22 shown in FIG. 5(c) is assumed to be longer than the period from time t1 to time t2 shown in FIG. 4(d).

In this case, the integrated value of the current flowing through battery B during the period from time t3 to time t4' shown in FIG. Larger than the integrated value of current.

Therefore, the charge capacity of the battery B at the end of charging when the charging voltage and the end current stored in the storage unit 9 are the reference charging voltage Vr and the end current I2 are the charging voltage and the end current stored in the storage unit 9. It is larger than the charge capacity of the battery B at the end of charging when the end current is the reference charging voltage Vr and the end current I1.

That is, when the charging voltage and the end current stored in the storage unit 9 are the reference charging voltage Vr and the end current I2, the charging voltage and the end current stored in the storage unit 9 are the reference charging voltage Vr and the end current I1. As compared with the case of , the traveling distance and traveling time of the vehicle Ve can be extended.

Further, the integrated value of the current flowing through the battery B during the period from time t1' to time t5' shown in FIG. It becomes the same as the integrated current value. The integrated value of the current flowing through the battery B during the period from time t0 to time t1′ shown in FIG. 5B is the integrated current flowing through the battery B during the period from time t0 to time t1 shown in FIG. greater than the value.

Therefore, the charge capacity of the battery B at the end of charging when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V2 and the reference end current Ir are the charging voltage and the end current stored in the storage unit 9. It is larger than the charge capacity of the battery B at the end of charging when the end current is the charging voltage V1 and the reference end current Ir.

That is, when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V2 and the reference end current Ir, the charging voltage and the end current stored in the storage unit 9 are the charging voltage V1 and the reference end current Ir. As compared with the case of , the traveling distance and traveling time of the vehicle Ve can be extended.

Also, the integrated value of the current flowing through the battery B during the period from time t0 to time t11 shown in FIG. Larger than the integrated value. The integrated value of the current flowing through the battery B during the period from time t11 to time t22 shown in FIG. 5(c) is the integrated value of the current flowing through the battery B during the period from time t1 to time t2 shown in FIG. 4(d). get bigger.

Therefore, the charge capacity of the battery B at the end of charging when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V2 and the end current I2 are the charging voltage and the end current stored in the storage unit 9. It is larger than the charge capacity of the battery B at the end of charging when the current is the charging voltage V1 and the end current I1.

That is, when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V2 and the end current I2, the charging voltage and the end current stored in the storage unit 9 are the charging voltage V1 and the end current I1. Compared to the case, the traveling distance and traveling time of the vehicle Ve can be extended.

As described above, in the charging control apparatus of the embodiment, when the charge capacity of the battery B may be relatively small, such as when the usage amount of the vehicle Ve per unit time is small, the end current stored in the storage unit 9 is changed to or change the charging voltage stored in the storage unit 9 to the charging voltage V1, or change the charging voltage stored in the storage unit 9 to the charging voltage V1 and change the storage unit 9 to the end current I1. As a result, the charge capacity of the battery B after charging can be reduced, and deterioration of the battery B can be suppressed. In addition, since the configuration is such that charging is controlled using the voltage of the battery B being charged and the current flowing through the battery B, charging is controlled using the charge capacity estimated from the integrated value of the current flowing through the battery B being charged. Compared to the case where the battery B is overcharged, the effect of the measurement error of the ammeter 7 can be reduced and the charge capacity of the battery B after charging can be brought closer to the true charge capacity, and the true charge capacity corresponds to the overcharged state of the battery B. It is possible to reduce the deterioration of the battery B beyond the threshold value. That is, the charge amount of the battery B can be optimized according to the usage condition of the vehicle Ve.

Moreover, the present invention is not limited to the above embodiments, and various improvements and modifications are possible without departing from the gist of the present invention.

<Modification>
In the above embodiment, the battery B is charged by performing constant current voltage control and constant voltage charge control, but the battery B may be charged by performing only constant current charge control.

When configured in this manner, the storage unit 9 stores the charging voltage. Also, the changing unit 11 changes the charging voltage stored in the storage unit 9 . In addition, when the charging control unit 12 keeps the current flowing through the battery B constant during constant current charging control, when the voltage of the battery B becomes equal to or higher than the charging voltage stored in the storage unit 9, the current flowing through the battery B Let the current go to zero.

Note that the changing unit 11 may be configured to change the charging voltage stored in the storage unit 9 to the charging voltage V1 according to the usage status of the vehicle Ve or an instruction from the user. As a result, the charge capacity of the battery B after charging can be reduced, and deterioration of the battery B can be suppressed. In addition, since the configuration is such that charging is controlled using the voltage of the battery B being charged, compared to the case of controlling charging using the charge capacity estimated from the integrated value of the current flowing through the battery B being charged, The charge capacity of the battery B after charging can be approximated to the true charge capacity by eliminating the influence of the measurement error of the ammeter 7, and the true charge capacity exceeds the threshold value corresponding to the overcharged state of the battery B. deterioration can be reduced. That is, the charge amount of the battery B can be optimized according to the usage condition of the vehicle Ve.

Further, the changing unit 11 may be configured to change the charging voltage stored in the storage unit 9 to the charging voltage V2 according to the temperature of the battery B or the degree of deterioration of the battery B. FIG. As a result, the voltage of the battery B is stored in the storage unit 9 even if the internal resistance of the battery B increases due to the temperature rise of the battery B or deterioration of the battery B and the voltage of the battery B during charging increases. Since it is possible to make it difficult to exceed the charging voltage, it is possible to suppress the decrease in the charge capacity of the battery B, and the travel distance and the travel time of the vehicle Ve increase due to the temperature rise of the battery B and the deterioration of the battery B. Decrease can be suppressed.

1 storage unit 2 control unit 3 power conversion unit 4 storage unit 5 control unit 6 voltmeter 7 ammeter 8 thermometer 9 storage unit 10 control unit 11 change unit 12 charge control unit

Claims (5)

A charging control device for controlling charging of a battery mounted on a vehicle,
a storage unit that stores the charging voltage and the termination current;
a changing unit that changes at least one of the charging voltage and the termination current stored in the storage unit;
When the voltage of the battery becomes equal to or higher than the charging voltage stored in the storage unit when the current flowing through the battery is kept constant, the current flowing through the battery is gradually decreased, and the current flowing through the battery is reduced to the a charging control unit that causes the current flowing through the battery to become zero when the current is equal to or less than the end current stored in the storage unit;
with
The change unit changes the end current stored in the storage unit to a first end current that is larger than a reference end current, or changes the end current stored in the storage unit according to the usage state of the vehicle, or changes the end current stored in the storage unit. changing the voltage to a first charging voltage that is lower than the reference charging voltage, or changing the charging voltage stored in the storage unit to the first charging voltage and changing the end current stored in the storage unit to the first charging voltage; A charging control device, characterized in that the current is changed to the first termination current. A charging control device for controlling charging of a battery mounted on a vehicle,
a storage unit that stores the charging voltage and the termination current;
a changing unit that changes at least one of the charging voltage and the termination current stored in the storage unit;
When the voltage of the battery becomes equal to or higher than the charging voltage stored in the storage unit when the current flowing through the battery is kept constant, the current flowing through the battery is gradually decreased, and the current flowing through the battery is reduced to the a charging control unit that causes the current flowing through the battery to become zero when the current is equal to or less than the end current stored in the storage unit;
with
The change unit changes the end current stored in the storage unit when the usage amount of the vehicle per unit time is equal to or less than a first threshold value and is greater than a second threshold value which is smaller than the first threshold value. is changed to a first end current that is greater than the reference end current, and the usage amount of the vehicle per unit time is equal to or less than the second threshold and is greater than a third threshold that is less than the second threshold and changing the charging voltage stored in the storage unit to a first charging voltage that is lower than the reference charging voltage, and if the usage amount of the vehicle per unit time is equal to or less than the third threshold value, the storage unit stores A charging control device that changes a stored charging voltage to the first charging voltage and changes a termination current stored in the storage section to the first termination current. The charging control device according to claim 1 or 2,
The changing unit changes the end current stored in the storage unit to a second end current that is larger than the reference end current and smaller than the first end current, according to the temperature of the battery or the degree of deterioration of the battery. or the charging voltage stored in the storage unit is changed to a second charging voltage that is smaller than the reference charging voltage and larger than the first charging voltage, or the storage unit changing the charging voltage stored in the second charging voltage to the second charging voltage and changing the end current stored in the storage unit to the second end current. A charging control device for controlling charging of a battery mounted on a vehicle,
a storage unit that stores the charging voltage;
a changing unit that changes the charging voltage stored in the storage unit;
a charging control unit for reducing the current flowing through the battery to zero when the voltage of the battery becomes equal to or higher than the charging voltage stored in the storage unit when the current flowing through the battery is kept constant;
with
The charging control device, wherein the changing unit changes the charging voltage stored in the storage unit to a first charging voltage that is lower than a reference charging voltage, according to the usage condition of the vehicle. The charging control device according to claim 4,
The changing unit changes the charging voltage stored in the storage unit to a second voltage lower than the reference charging voltage and higher than the first charging voltage according to the temperature of the battery or the degree of deterioration of the battery. A charging control device characterized by changing to a charging voltage.

Images