JP2000116019A - Battery charging control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the performance of a battery at its best. SOLUTION: A device is provided with a means 26 for controlling equal charging or normal charging from a charger 38 to a battery 32 when the charger 38 is connected to the battery 32 that is fitted to an electric car, and a first timer means 4 for counting elapsed time starting from the time when a power switch 24 of the electric car is turned off as the start time. Further, the control means 26 is provided with a first selection function 8 for selecting equal charging when the output of the first timer means 4 exceeds a preset value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery charge control device, and more particularly to a battery charge control device for controlling charging of a battery mounted on an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, charging of a battery mounted on an electric vehicle is always optimal because charging characteristics change due to the influence of the depth of discharge of the battery, leaving time, deterioration state, ambient temperature, and the like. It is difficult. Repeated undercharging tends to lower the battery capacity early, and repeated overcharging reduces the battery life.

[0003] The equal charging method is a method of charging the battery for a longer time than the normal charging time or increasing the charging voltage to increase the charging amount. In order not to cause a drop or the like, equal charging is performed once, for example, several times by manual operation.

[0004] There is also a method of automatically determining which of normal charging and equal charging should be performed.
For example, Japanese Patent Application Laid-Open No. 5-146084 discloses a method of automatically selecting an appropriate one of normal charging and equal charging in accordance with a battery temperature (seasonal difference or regional difference) at the time of charging. Here, the number of times of charging is multiplied by a coefficient predetermined for each battery temperature, and whether or not to perform equal charging is determined based on this value. Select charging. Furthermore, Japanese Patent Application Laid-Open No. 8-140209 discloses a method of performing uniform charging based on the number of times of charging of a battery, the total value of the amount of charge / discharge power after uniform charging, and the like.

[0005]

However, in the above-mentioned conventional example, since the equal charging is performed only based on the number of times of charging and the temperature, there is a disadvantage that the life of the battery cannot always be maximized. In addition, there is an inconvenience that it is difficult to always maintain the battery in good condition.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery charge control device which can solve the disadvantages of the prior art and, in particular, can maintain the performance of the battery in the best condition.

[0007]

Therefore, according to the present invention, when a charger is connected to a battery mounted on an electric vehicle, control means for controlling equal charging or normal charging from the charger to the battery, A first timing means for counting an elapsed time from the time when the power switch of the electric vehicle is turned off. In addition, the control means is provided with a first selection function of selecting the equal charging when the output of the first timing means exceeds a predetermined value. This aims to achieve the above-mentioned object.

According to the present invention, the first timing means measures the time since the power switch of the electric vehicle was turned off.
If the battery is left unused for a long period of time, the battery becomes inactive as the depth of discharge becomes deeper and the battery is left unused for a longer time. If it is determined that the time has passed and the leaving time is long, the control means selects the equal charge (first selection function). In addition, even when a long time has elapsed since the previous charging (second selection function) or when the depth of discharge is deep (fourth selection function), the uniform charging is selected.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a battery charge control device according to the present invention. The battery charge control device includes a battery charger 32 attached to the battery 32 mounted on the electric vehicle.
And the control means 26 for controlling the equal charge or the normal charge from the charger 38 to the battery 32 when the battery is connected, and the elapsed time from the time when the power switch 24 of the electric vehicle is turned off. A first timer 4 for measuring time. In addition, the control means 26 has a first selection function 8 for selecting equal charging when the output of the first time counting means 4 exceeds a predetermined value. The first selection function 8 selects one of the uniform charging and the normal charging based on the elapsed time from when the power switch is turned off. Here, when the electric vehicle is not operated for a long time and the battery has been left for a certain period of time or longer, the inactivated battery is immediately activated by performing equal charging.

Further, in one embodiment, a second time measuring means 6 is provided for measuring the time elapsed from the time when the charging of the battery 32 is completed, and the control means 26 controls the second time. A second selection function 9 is provided for selecting equal charging when the output of the timer 6 exceeds a predetermined value. The second selection function 9 selects equal charging when a predetermined period has passed since the end of the previous charging. Then, a certain period of time can be passed only by discharging the battery, and charging immediately after the battery becomes inactive can be equalized, thereby maximizing the performance of the battery.

In some embodiments, the control means includes:
When the equal charge is selected by the first or second selection function, a third selection function of selecting the equal charge for the next charge after the end of the charge by the equal charge may be provided. When the battery becomes inactive, it is easier to activate the battery when the equal charge is repeated twice than when the equal charge is performed only once.
Therefore, when the equal charge is once selected, the next time is also the equal charge. After the second equal charge, the control is returned to the normal control.

[0013] The selection between the equal charge and the normal charge may be determined according to the depth of discharge of the battery. In the embodiment in this case, there is provided a remaining amount measuring means 2 for measuring the remaining capacity of the battery mounted on the electric vehicle.
Then, the control means 26 has a fourth selection function 11 for selecting equal charging when the remaining battery capacity is equal to or less than a predetermined value.

FIG. 3 is a block diagram showing the configuration of hardware resources according to the present embodiment. As shown in FIG. 2, the electric system of the electric vehicle includes first and second motors 28 and 30 for driving the electric vehicle, a main controller (control means) 26 for controlling the amount of rotation of the motor, The controller includes first and second batteries 32 and 34 for supplying power to the controller 26 and each motor, and a joystick controller 20 for transmitting a drive command to the main controller. The first and second motors input the number of rotations of the motor to the main controller 26.

The joystick controller 20 includes an operation knob 22 for controlling the traveling direction of the electric vehicle, a power switch 24, and the display panel 12 for displaying the remaining battery power. Joystick controller 2
0 outputs an accelerator signal and a maximum speed setting signal to the main controller. A charger 38 that supplies power to the batteries 32 and 34 is connected to the batteries 32 and 34 and the main controller 26 via a connector 42. This charger 38 has an AC plug 40. FIG.
In the example shown in FIG. 7, the first battery 32 is equipped with a temperature sensor 36. This temperature sensor 36 measures the temperature of the battery and outputs it to the main controller.

As shown in FIG. 3, the main controller 2
Reference numeral 6 denotes a one-chip microcomputer 50 which stores discharge characteristic data of the batteries 32 and 34 and a program for calculating the remaining battery charge, and operates according to the programs and data.
A power supply circuit 46 for converting a voltage of electric power supplied from the batteries 32 and 34 to a control voltage;
And a current detection circuit 48 for amplifying the voltage between both ends of the microcomputer 50 and outputting the amplified voltage to the A / D input port of the microcomputer 50. The microcomputer 50 performs a cumulative operation on the value input from the A / D input port to calculate the amount of consumed current and the amount of charged current. As a method of displaying the remaining battery level, there are an LED multi-point lighting type, a liquid crystal display, a several-order type using seven segments, and the like. In addition, as a mathematical expression, there is a method of displaying the remaining travel distance, the remaining travel time, the remaining battery capacity, and the like. FIG. 5 is an explanatory diagram for explaining the display panel (remaining amount display means) 12 according to the present embodiment. As shown in FIG.
Is equipped with a battery fuel gauge that displays the remaining power in six stages, and a time indicator that displays the time that can be traveled before the next charge. FIG. 5B shows the relationship between the display on the battery fuel gauge and the remaining battery capacity (denoted as capacity in the figure).

The microcomputer 50 operates according to a program stored in advance to realize each means and each function of the control system shown in FIG. When the power switch 24 of the joystick controller 20 is turned on, power is supplied to the control systems of the joystick controller and the main controller, and the one-chip microcomputer incorporated therein is activated. When the charger 38 and the batteries 32 and 34 are connected via the connectors 42 and 44, the main controller 26 starts charging control.

FIG. 5 is a graph showing charging characteristics of constant current / constant voltage charging, and FIG. 6 is a graph showing charging characteristics of constant current / constant voltage / constant current charging. In the present embodiment, the constant current-constant voltage type charging shown in FIG. 5 is set to normal charging. The constant current-constant voltage-constant current type charging is set to the uniform charging. In addition, both may be of a constant current-constant voltage-constant current type charging, and the charging time may be lengthened only in the case of uniform charging.

In the case of constant current-constant voltage charging, since the beginning of charging is a constant current, the generation of a large current does not shorten the life of the battery. Then, when a certain battery terminal voltage becomes a certain value, the voltage is switched to a constant voltage. Thereafter, when the battery is charged at a constant voltage, the current becomes smaller as the charging progresses. Therefore, not only the efficiency of the charging is improved, but also gas generation due to decomposition of water due to the charging current is almost eliminated. Further, when charging is further continued at a constant current after charging at a constant voltage, a difference in voltage value between a plurality of battery blocks can be reduced.

Next, an example of a charge control process executed by the microcomputer 50 will be described with reference to FIGS.

In this example, the battery temperature, the remaining battery level, the elapsed time after turning off the power switch of the electric vehicle,
Either equal charging or normal charging is selected in consideration of all the elapsed time since the previous charging was completed. Further, a counter for counting the number of times of charging is provided, and based on the count value, equal charging and normal charging are selected.

As shown in FIG. 7, when the power switch of the electric vehicle is turned on, the pre-stored remaining battery level is read, and it is checked whether the remaining level is equal to or greater than a predetermined value X (see FIG. 7). Step S1). This value X is set before and after the discharge end voltage of the battery. When the remaining battery charge is lower than the discharge end voltage X, for example, the code 1 shown in FIG. 7 is selected. Reference numeral 1 is a selection of equal charging as shown in FIG. 8, and reference numeral 2 is a selection of normal charging.

If the remaining battery charge is equal to or greater than X, a determination process based on the battery temperature is performed. If the battery temperature is lower than, for example, 10 degrees, the battery is likely to be inactive. If the battery temperature is equal to or lower than T1 (for example, 10 degrees), uniform charging is selected (step S2).

Subsequently, the frequency of selecting uniform charging is made different depending on the battery temperature. Here, T1 <T2 <
T3 is, for example, 15 degrees, and T3 is, for example, 20 degrees. If the battery temperature is equal to or lower than T2 (step S
3) Read the value of the charge counter (step S4).
In step S5, the ratio of the uniform charging is set higher than the normal charging. For example, if the value of the charge counter is 1, equal charge is selected, and if it is 3, normal charge is selected. Therefore, equal charging is performed twice in three times of charging.

Similarly, if the battery temperature is equal to or lower than T3 (step S6), the charging is performed twice every four times (steps S7 and S8). If the battery temperature exceeds T3,
Equal charging is performed twice every five times (steps S9 and S10).
By changing the frequency of selecting the uniform charging depending on the temperature in this way, it is possible to appropriately cope with the inactivation of the battery due to the temperature drop.

Equal charging or normal charging is started (steps S21 and S22), and when charging is completed (step S2).
3) reset the values of the first timer and the second timer. Here, the first timer is an example of the first time measuring means 4 shown in FIG. 1, and measures the elapsed time after the power switch is turned off. The second timer is an example of the second timer 6 shown in FIG. 1, and measures the elapsed time after the previous charging is completed.

When charging is completed (step S23), the first
When both the timer and the second timer are reset, the value of the number of times of charging is continuously increased by 1 (step S
25). And a second timer for measuring the elapsed time after the end of charging.
The value of the timer is incremented by one. If the value of the second timer is equal to or greater than the predetermined value A (step S2
7) Assuming that a long time has elapsed since the end of charging, the value of the charge counter is reset to 1 (step S28).

On the other hand, if the value of the second timer does not exceed A, for example, immediately after the end of charging, it is checked whether or not there is a charging start command.
Return to If there is no charge start command, it is checked whether the power switch of the electric vehicle is on. On the other hand, if it is not on, the value of the first timer that measures the time elapsed since the power switch was turned off is increased by "1". Then, the first
It is determined whether or not the value of the timer has exceeded a predetermined value B (step S32). If the time elapsed since the power switch was turned off exceeds a predetermined value B, the value of the charge counter is reset (step S28). When the value of the charge counter is reset to “1”, the next charge is equal charge.

If the power switch is turned on in step S30, the first timer is reset (step S33), and the process proceeds to step S34. If it is determined in step S32 that the value of the timer 1 has not exceeded B, the process proceeds to step S34. In a loop returning from step S34 to step S26, the values of the second timer and the first timer are counted up at regular intervals. In step S34, the process waits for this fixed period.

As described above, when the battery becomes inactive according to the state of the battery by the processing shown in FIGS. 7 and 8, it is possible to make the charging immediately thereafter equal to the charging.

[0031]

According to the present invention, the control means determines that the output from the first time-measuring means exceeds a predetermined value and that the idle time is long. If the battery is left unused for a long time, the longer the remaining time is, the more inactive the battery becomes, but the normal charging is performed in the inactive state. The battery can be immediately refreshed by the equal charge without the need for the battery, so that the condition of the battery can always be in a good state.Furthermore, the equal charge immediately after the battery becomes inactive reduces the life of the battery. Accordingly, it is possible to provide an unprecedented excellent battery charge control device capable of maximizing the performance of the battery.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of hardware resources of the example shown in FIG.

FIG. 3 is a circuit diagram showing a configuration example of a main controller shown in FIG. 2;

4A and 4B are explanatory diagrams for explaining the display panel shown in FIG. 2; FIG. 4A is a diagram showing a display example on the display panel, and FIG. 4B is a diagram showing a display on the display panel; It is a figure which shows a meaning.

FIG. 5 is a graph showing charging characteristics of constant current-constant voltage charging.

FIG. 6 is a graph showing charging characteristics of constant current-constant voltage-constant current charging.

FIG. 7 is a flowchart illustrating a first stage of a processing example of selecting between equal charging and normal charging by the microcomputer illustrated in FIG. 3;

FIG. 8 is a flowchart illustrating a second half of a processing example of selecting between equal charging and normal charging by the microcomputer illustrated in FIG. 3;

[Explanation of symbols]

 4 First Timekeeping Means 6 Second Timekeeping Means 26 Control Means (Main Controller) 32 Battery 38 Charger

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (6)

[Claims] 1. A control means for controlling equal charging or normal charging of the battery from the charger when the charger is connected to the battery mounted on the electric vehicle, and turning off a power switch of the electric vehicle. A first time measuring means for measuring an elapsed time from the time when the time is counted as a counting time, wherein the control means outputs an output of the first time counting means exceeding a predetermined value. The first to choose the equal charge
A battery charge control device comprising a selection function of: 2. The control means further includes a second time counting means for counting an elapsed time from the time when the charging of the battery is completed as a counting time, wherein the control means includes a second counting means for counting the time elapsed from the counting time. 2. The battery charge control device according to claim 1, further comprising a second selection function of selecting equal charging when the output of said time measuring means exceeds a predetermined value. 3. The method according to claim 1, wherein when the equal charge is selected by the first or second selection function, the control means selects the equal charge for the next charge after the end of the charge by the equal charge. 3. The battery charge control device according to claim 2, further comprising a selection function. 4. The control means has a setting function of setting a constant current-constant voltage charging to the normal charging and setting a constant current-constant voltage-constant current charging to the uniform charging. The battery charge control device according to claim 1, 2, or 3. 5. A remaining amount measuring means for measuring a remaining capacity of a battery mounted on an electric vehicle, and controlling equal charging or normal charging from the charger to the battery when the charger is connected to the battery. A battery charging control device, comprising: a fourth selecting function of selecting the equal charging when the remaining battery capacity is equal to or less than a predetermined value. . 6. The control means includes: first time counting means for counting an elapsed time from the time when the power switch of the electric vehicle is turned off; and charging of the battery is completed. And a second timing means for counting an elapsed time from the counting time with the counting time as a counting time, wherein the control means controls the output of the first timing means or the output of the second timing means respectively. The battery charge control device according to claim 5, further comprising a fifth selection function of selecting the equal charge when the value exceeds a predetermined value.