JP2000333382A - Battery charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery charger for surely recognizing a charging state in a battery. SOLUTION: A microprocessor detects switching operation of a setting current value of a multiple-stage constant-current battery charger 5, and lamps 1 to 4 are lighted up sequentially for each finished charging step to indicate the process of charging states. Only the last lamp corresponding the current charging step is indicated in a lighted state, so that the charging process in execution is clearly indicated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a battery charging device suitable for charging a battery of an electric vehicle.

[0002]

2. Description of the Related Art As a battery charger of this type, a constant voltage type battery charger for applying a constant voltage to a battery to perform a charging operation, or a charging operation with a constant value of a charging current, is performed. A multi-stage battery charging device of a constant current type that performs a charging operation with a large current in an initial stage of charging, and then performs a plurality of charging processes while gradually reducing the charging current as the charging progresses. 2. Description of the Related Art Constant current battery chargers are known.

[0003] Further, a battery for an electric vehicle is advantageously a high-voltage battery formed by connecting a plurality of cells in series from the viewpoint of the operating efficiency of a driving motor and an inverter for controlling the same. As a charging device used for a battery for an electric vehicle, a multi-stage constant current type battery charging device that facilitates rapid charging and secures a charging capacity is preferable.

[0004]

FIG. 7 is a front view showing a conventional example of a multistage constant current type battery charger. A power switch 1 for turning on AC power to the battery charger is provided on a front panel 101 of the battery charger 100.
02, a power lamp 103 for checking the ON / OFF state of the AC power supply, a charging lamp 104 for checking the connection state of the battery to be charged, and a charging completion lamp 105 for notifying the completion of charging. Has been deployed. However, in such a configuration, only the start and completion of charging are recognized, and it is not possible to know how much the battery is charged in the charging process, which is inconvenient in checking the required charging time and remaining time. Met.

A charge state display device for displaying the charge state of a battery on the side of an electric vehicle equipped with the battery has been proposed in Japanese Patent Laid-Open No. 7-87607. In this device, an indicator lamp is provided near the charging connector on the electric vehicle side, and the state of charge of the battery is displayed by a change in the light emission state or the color of the light emission. There are only two states of start (during charging) and completion of charging, and also has the disadvantage that it is difficult to grasp the charging process of the battery as described above.

[0006]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a battery charging apparatus which solves the above-mentioned drawbacks of the prior art and which can accurately grasp the state of charge of a battery even while the battery is being charged.

[0007]

According to the present invention, there is provided a battery charging apparatus comprising: a power supply unit for applying a charging voltage to a battery while maintaining a set current value; and a charging voltage monitoring unit for monitoring a charging voltage applied to the battery. Means, and when the charging voltage monitoring means detects a charging voltage equal to or higher than a set value, a set current value switching means for switching a set current value of the power supply means to a set current value of a next charging process lower than the set value so far. A multi-stage constant current type battery charging device, comprising: a charging process identification unit that identifies a current charging process based on a switching operation of a set current value by the setting current value switching unit; and a charging process identification unit that identifies the current charging process. Charging process display means for visually displaying the current charging process that has been performed. The power supply unit applies a charging voltage to the battery while holding the set current value, and the charging voltage monitoring unit monitors the charging voltage applied to the battery. Then, when the charging voltage monitoring means detects a charging voltage equal to or higher than the set value, the set current value switching means switches the set current value of the power supply means to a set current value in the next charging process lower than the set value so far. This repetition achieves a multi-stage constant current type charging operation in which a plurality of charging steps are performed while the charging current is gradually reduced as the charging progresses. During this time, the charging process identification means identifies the current charging process based on the switching operation of the set current value by the setting current value switching means,
The charging process display means visually displays the current charging process.

When the charging process is displayed by the charging process display means having a plurality of lamps, the above-mentioned charging process display means displays a lighting lamp control means for specifying the number of lamps to be turned on in accordance with the current charging process. Is provided in the charging process display means described above.

In this case, it is desirable that a plurality of lamps indicating the charging process be arranged in a straight line. Further, the lighting lamp control means is provided with a lighting order control function, and the plurality of lamps are sequentially turned on from one end of the straight line to the other end in accordance with the current charging process. Further, the current lamp charging means is provided with a blinking display function of the current charging process, and the lamp lit last, that is, the lamp corresponding to the current charging process is blinked and displayed, so that the progress of the charging process can be more easily grasped. To do.

[0010] The lighting lamp control means is provided with a charge completion display function for detecting the completion of the charging process of the last stage and lighting the charge completion lamp so that the completion of charging can be clearly recognized.

As the charging process display means, a liquid crystal display or the like can be used in addition to the lamp.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which the present invention is applied to a battery charger for an electric vehicle will be described in detail. FIG. 1A is a front view showing the external appearance of a battery charging device 5 according to one embodiment, and FIG. 2 is a block diagram schematically showing a circuit configuration of the battery charging device 5 according to the embodiment.

As shown in FIG. 1A, a front panel 6 of the battery charger 5 has an A
A power switch 102 for turning on the C power and a power lamp 10 for checking the ON / OFF state of the AC power
3, and a charging completion lamp 105 for notifying the completion of charging is provided in substantially the same manner as the conventional example shown in FIG. Reference numeral 7 denotes an alarm lamp for notifying charging abnormality, and reference numeral 106 denotes a handle used when the battery charger 5 is carried. In FIG. 1A, the battery on the electric vehicle and the battery charger 5 are used. And a power cord connecting port for connecting the AC power supply and the battery charger 5 are not described.

Each of lamp 1, lamp 2, lamp 3, and lamp 4, which constitute a part of the charging process display means,
As shown in FIG. 1 (a), the lamp is linearly arranged on the nameplate 8 of the front panel 6, and is lit and displayed in the order of lamp 1, lamp 2, lamp 3, and lamp 4 in accordance with the charging process of the battery. It has become so. In this embodiment, a four-stage multi-stage constant-current charging as shown in FIG. 3A is applied, and when the charging process of the first stage is completed, the lamp 1 is charged.
However, when the charging process of the second stage is completed, the lamp 2 is turned on, and when the charging process of the third stage is completed, the lamp 3 is turned on. Further, the lamp 4 is turned on when the charging process of the fourth stage, that is, the charging process of the last stage is completed, and the lamp that is turned on lastly, that is, the lamp corresponding to the charging process at that time blinks. It is displayed.

In the example shown in FIG.
The number of stages of the charging process corresponding to 2, 3, and 4 is indicated on the nameplate 8 as “1”.
The letters "stage", "two-stage", "three-stage", and "four-stage" are indicated by letters so that the correspondence between the lighting or blinking state of each lamp and the number of stages in the charging process can be easily understood. Also, instead of the notations “1 stage”, “2 stage”, “3 stage”, “4 stage”, “charging rate 70%”, “charging rate 80
%, Charging rate 90%, charging completed, etc., or charging, such as "8 hours", "6 hours", "4 hours", "within 2 hours", etc. In some cases, the notation of the required time is used. In particular, in the case of the battery charger 5 for an electric vehicle, “running is not possible”, “requires charging”,
Notations such as “running permitted” and “charging completed” are also practically suitable.

Further, in place of the nameplate 8 shown in FIG.
A nameplate 8a as shown in (b) may be provided on the front panel 6. In the nameplate 8a, "1st step", "2nd step", "3rd step", "4th step" in the nameplate 8 of FIG.
In addition to the notation using the character “dan”, a symbol display 9 in the form of a line graph is used.
The magnitude of the charging capacity is indicated by the distance between each of the lamps 1, 2, 3, and 4 and the corresponding position on the outline 9a of the symbol display 9, and the meaning thereof is obvious at a glance.

As shown in FIG. 2, the battery charger 5 comprises:
A power supply unit 11 for taking in power from an external AC power supply 10 to transform the power; a rectifying unit 12 for rectifying an output of the power supply unit 11 and passing it to a DC power supply unit 13;
DC power supply unit 13 for adjusting the applied voltage to
It includes a current detection unit 14 for detecting the magnitude of a current generated by applying a voltage to the battery 17, a voltage detection unit 15 for detecting a charging voltage applied to the battery 17, and a charging control unit 16.

The charge control section 16 includes a microprocessor 16a, a ROM, a RAM, and the like. The microprocessor 16a sequentially reads the current value detected by the current detection unit 14, and adjusts the output voltage of the DC power supply unit 13, that is, the charging voltage for the battery 17 so that the current value matches the set current value. . That is, the power supply means in the present embodiment is constituted by the microprocessor 16a of the charging control unit 16 and the DC power supply unit 13, and the battery 17 is charged while maintaining the set current value by the interaction of these elements. A voltage will be applied.

The microprocessor 16a as set current value switching means monitors the value of the voltage detected by the voltage detector 14 as charge voltage monitoring means, and when this voltage value reaches the set charge voltage, charging is performed. The set current value in the control unit 16 is switched to the set current value for the next charging process that is lower than the set value up to that time.

As described above, in this embodiment, FIG.
A four-stage multi-stage constant current charging as shown in FIG. 7A is applied, and a set current value I to be applied to a first-stage charging process.
₁ , a set current value I ₂ to be applied to the second stage charging process, a set current value I ₃ to be applied to the third stage charging process, and a set current value I ₄ to be applied to the fourth stage charging process Each value is stored in the ROM of the charge control unit 16 in advance.

The microprocessor 16a of the charging control unit 16 also functions as a drive control circuit for each of the lamps 1, 2, 3, and 4.

The reference numeral 18 in FIG.
Reference numeral 19 denotes a connector for inserting a power cord for connecting the battery of the electric vehicle to the battery charger 5, and a connector for inserting a power cord for connecting the battery charger 5 to the battery charger 5.

FIGS. 4 and 5 are flowcharts showing the outline of the lamp lighting process executed by the microprocessor 16a of the charging control section 16 which also serves as a part of the charging process identifying means and the charging process displaying means.

When the operator turns on the battery charger 5 by operating the power switch 102 while the battery charger 5 is connected to the AC power supply 10, the microprocessor 16a first turns on the power lamp 103 (step S1). s1) The current value is read from the current detector 14 to determine whether or not the battery 17 to be charged is connected. If the battery 17 is not connected, the process stands by (step s2).

When the connection of the battery 17 is detected, the microprocessor 16a switches the lamps 1, 2, 3, 4
The drive command to the controller is initialized to turn off (step s3). Then, the microprocessor 16a sets an initial value 1 to the index j for storing the number of stages of the charging process (step s4), the value of the set current value I _j from the ROM of the charge control unit 16 based on the value of the index j Is read, and the value is set in the charge control unit 16 as the set current value of the j-th stage (step s5).

Next, the microprocessor 16a initializes the value of the timer T for measuring the time required for the charging process to 0 and starts it (step s6), and turns on the lighting having the lighting order control function and the current charging process blinking display function. The microprocessor 16a as a lamp control means starts blinking of the lamp j corresponding to the current value of the index j (step s).
7). Since the current value of the index j is 1 at the current stage immediately after the start of charging, at this stage, the lamps 2, 3, and 4 are turned off as shown in the table of FIG. Only the lamp 1 located at the position is blinked. As described above, the blinking display indicates the charging process that is being performed at that time, and the configuration of the nameplate 8 as shown in FIG. 1A allows the operator to perform the first-stage charging process. Can be easily recognized.

Next, the microprocessor 16a reads the current value V of the charging voltage applied to the battery 17 via the voltage detector 15 constituting the charging voltage monitoring means (step s8), and reads the current value V of the charging voltage. Is higher than the set charging voltage Vx (step s).
9). Note that the set charging voltage Vx is a set value for determining whether or not to shift to the next charging step. In this embodiment, the value of Vx is set according to the characteristics of the battery 17 for 240 volts. It is set to 288 volts.

The current value V of the charging voltage is equal to the set charging voltage Vx.
If not, the microprocessor 16a updates
In addition, the measurement time of the timer T is required for the charging process of the j-th stage.
Time T _jIs determined (step s1).
0), if not exceeded, steps s8 to
While repeatedly executing the processing of step s10, the charging of the j-th stage is performed.
Wait for the completion of the charging process. During this time, other processing is performed
There is no lighting status of lamps 1, 2, 3, 4
Is maintained in the same state as. That is, the first stage charging process
At this stage, lamps 2, 3 and 4 are turned off
The state where only 1 is displayed blinking is maintained.
The progress of charging during this time is shown in FIG.
As shown.

[0029] Then, when the measurement time of the timer T is the current value V of the charging voltage exceeds the set charging voltage Vx before exceeding the allowable duration T _j of the charging process of the j stage, that is, the question of the step s10 If the result of the determination in step s9 is true before the result of step S9 is true, and it is confirmed that the j-th charging process has been completed successfully, the microprocessor 16a
Changes the display mode of the lamp j corresponding to the current value of the index j, that is, the lamp j which has been blinking so far from blinking to lighting, and indicates to the operator that the charging process of the j-th stage is completed ( Step s13).

Next, the microprocessor 16a as the charging process discriminating means increments the value of the index j by 1 and stores the number of stages of the charging process to be executed next (step s14). (Step s15). In the present embodiment, the value of n is 4 because four-stage multi-stage constant-current charging is applied.

If the result of the determination in step s15 is false, it means that the charging process of the last stage has not been completed, that is, there is a charging process to be performed from now on. The process proceeds to step s5, and the processes in steps s5 to s10 are repeatedly executed in the same manner as described above to start the charging process in the next stage. However, at this stage, the aforementioned step s14
Since the value of the index j is incremented by 1 by the processing of the above, the current value of j is 2, the value of the set current value I _j is changed to the set current value I ₂ of the second stage charging process, and
Microprocessor 16 as lighting lamp control means having lighting order control function and current charging process blinking display function
The lamp j blinking by a is also changed to the lamp 2 corresponding to the charging process of the second stage.

Thereafter, whenever it is detected that the current value V of the charging voltage has exceeded the set charging voltage Vx by the determination processing of step s9, the processing of steps s13 to s15 and s5 to s10 is performed in the same manner as described above. Is repeatedly performed, and the microprocessor 16a as the charging process identification means and the charging process display means switches the display of the lamp corresponding to the charging process for which the charging operation has been completed from blinking to lighting, and displays the current charging process blinking. The microprocessor 16a that achieves the function causes the lamp corresponding to the newly started charging process to blink.

FIG. 3B shows the relationship between the charging processes of the first to fourth stages and the lighting modes of the lamps 1, 2, 3, and 4 in each charging process. As shown in FIG. 3B, all the lamps for which the corresponding charging process has been completed are lit and displayed.
Further, the lamp that is turned on lastly, that is, the lamp corresponding to the charging process that is currently being performed, is blinked. As described above, the lamps are sequentially turned on from one end of the linear lamp array to the other end in accordance with the progress of the charging process, so that the progress of the charging can be confirmed intuitively and easily. The charging process currently being performed can be accurately grasped by the blinking display.

When it is determined in step s15 that the value of the index j has exceeded the number n of stages in the last charging step during the execution of such a process repeatedly, the microprocessor 16a sets the final value. The charging operation for the battery 17 is stopped (step s16), the lamps 1, 2, 3, and 4 are turned off, and the charging completion lamp 105 is turned on (step s16). s
17) All the processes related to one charging operation are completed.

When it is desired to know only whether or not charging has been completed, it is sufficient to simply discriminate whether or not the lamp is blinking, and the determination is easy even from afar.

Further, the lamps 1 and 2 are displayed in red (warning color), the lamp 3 is displayed in yellow (color requiring attention), the lamp 4 is displayed in green (color indicating safety), etc., so that the charging process is considered. It is easier to grasp the progress of charging.

It should be noted that any one of j = 1 to n (4)
The determination result of step s10 when the electricity process is being performed
Is true, that is, the current value V of the charging voltage is set.
Before the charging voltage Vx is exceeded, the measurement time of the timer T is equal to the j-th stage.
Time T required for charging process _jIf you have exceeded
The microprocessor 16a operates the battery 16 to be charged.
Alarm assuming that there is something wrong with the battery 17
The lamp 7 is turned on (step s11), and the battery 17
Is stopped (step s12).

As described above, the battery charging apparatus 5 to which the four-stage multi-stage constant current charging is applied has been described as an embodiment, but the value of the parameter n used in the processing of FIGS. By changing the number of lamps to be mounted, it is possible to cope with multi-stage constant current charging of an arbitrary number of stages.

FIG. 6 is a diagram simply showing a battery charger 25 using a liquid crystal display 20 as a charging process display means instead of the lamps 1, 2, 3, and 4. FIG. 2 shows the overall circuit configuration and the flow of processing related to display.
And the flowcharts of FIGS. 4 and 5 are the same as those of FIG.

The liquid crystal display 20 mounted on the battery charger 25 has four display segments 21, 22, 23 and 24 instead of the above-mentioned lamps 1, 2, 3 and 4, and these display segments 21 and 22 are provided. , 23, and 24 are controlled to be turned on and off in the same manner as the lamps 1, 2, 3, and 4 described above. Further, each display segment 21,
Under the numerals 22, 23 and 24, numerical values "1", "2", "3" and "4" corresponding to the charging process are written on the front panel 6. In addition, reference numeral 26 is an arrow indicating a traveling direction of the charging process.

The display segments 21, 22, 23,
Each of the segments 24 is provided with a symbol display function equivalent to that of the nameplate 8a in the modification shown in FIG. 1B, and the charging rate for the battery 17 is determined by the outline 20a of each of the segments 21, 22, 23, and 24. Since the broken line graph shown is formed, it is easy to grasp the progress of charging. FIG. 6 shows a state where the second-stage charging process is being performed. Segment 21 is in a steady display state, segment 22 is in a blinking state, and segments 23 and 24 are in a non-display state. Has become. Illumination such as a backlight may be added to the liquid crystal display 20.

In place of the liquid crystal display 20, a display segment formed by collecting dot matrix LEDs or the like can be used.

[0043]

According to the battery charger of the present invention, the switching of the current in the charging process performed by the multi-stage constant current method is identified,
Since the current charging process is visually displayed by the charging process display means, even while the battery is being charged,
The progress of the charging of the battery can be accurately grasped.

Further, the charging process display means is constituted by using a plurality of lamps, and the number of lamps to be turned on is determined according to the current charging process. It can be grasped by subdividing with different resolutions.

Further, a plurality of lamps are arranged in a straight line, and additional lamps are sequentially turned on from one end of the straight line to the other end according to the progress of charging. Since the charging process being carried out at each stage is clearly indicated by the blinking display of the lamp, the overall progress of charging can be accurately grasped.

When the charging process of the last stage is completed, the charging completion lamp is lit and displayed, so that the completion of the final charging can be easily confirmed from a distance.

[Brief description of the drawings]

FIG. 1A is a front view showing an external appearance of a battery charger according to an embodiment of the present invention, and FIG. 1B is a front view showing a modification of a display unit applicable to the embodiment. It is.

FIG. 2 is a block diagram schematically showing a circuit configuration of the battery charger of the embodiment.

FIG. 3A is a graph showing a change in a charging state in the multi-stage constant current charging according to the embodiment in a relationship between a charging time and a charging voltage, and FIG. 3B is a graph showing a progress of a charging process and lighting of a lamp; It is a table which shows the relationship with a state.

FIG. 4 is a flowchart illustrating an outline of a lamp lighting process performed by a microprocessor of a charge control unit.

FIG. 5 is a continuation of the flowchart showing the outline of the lamp lighting process.

FIG. 6 is a front view showing a battery charger using a liquid crystal display as a charging process display means.

FIG. 7 is a front view showing a conventional example of a multi-stage constant current battery charger.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 lamp (part of charging process display means) 2 lamp (part of charging process display means) 3 lamp (part of charging process display means) 4 lamp (part of charging process display means) 5 battery charger 6 front Panel 7 Alarm lamp 8 Nameplate (part of charging process display means) 8a Nameplate (part of charging process display means) 9 Symbol display (part of charging process display means) 9a Outline (part of charging process display means) Reference Signs List 10 AC power supply 11 Power supply unit 12 Rectification unit 13 DC power supply unit (part of power supply unit) 14 Current detection unit 15 Voltage detection unit (charge voltage monitoring unit) 16 Charge control unit 16a Microprocessor (set current value switching unit, charging process) 17 battery 18 connector 19 connector 20 liquid crystal display (part of charging process display means) 20a segment of liquid crystal display Contour line 21 Segment of liquid crystal display 22 Segment of liquid crystal display 23 Segment of liquid crystal display 24 Segment of liquid crystal display 25 Battery charger 26 Arrow 100 Battery charger (conventional example) 101 Front panel 102 Power switch 103 Power lamp 104 Charging lamp 105 Charging completed lamp 106 Handle

Claims (5)

[Claims] 1. A power supply means for applying a charging voltage to a battery while holding a set current value, a charging voltage monitoring means for monitoring a charging voltage applied to the battery, and wherein the charging voltage monitoring means is at or above a set value. And a set current value switching means for switching the set current value of the power supply means to a set current value of a next charging process lower than the set value when the charging voltage is detected. A charging process identifying unit that identifies a current charging process based on a switching operation of the set current value by the set current value switching unit; and a charging device that visually displays the current charging process identified by the charging process identifying unit. A battery charging device provided with a process display means. 2. The charging process display means includes a plurality of lamps corresponding to the number of stages of the charging process, and lighting lamp control means for specifying a lighting number of the lamps according to a current charging process. The battery charger according to claim 1, wherein: 3. The lighting system according to claim 1, wherein the plurality of lamps are arranged in a straight line, and the lighting lamp control means sequentially switches the plurality of lamps from one end of the straight line to the other end in accordance with a current charging process. Lighting order control function to additionally light up,
3. A flashing display function of a current charging process for flashing and displaying a last-lit lamp is provided.
A battery charger as described. 4. The battery according to claim 3, wherein the lighting lamp control means is provided with a charging completion display function for detecting completion of a charging process in a final stage and lighting a charging completion lamp. Charging device. 5. The battery charger according to claim 2, wherein a liquid crystal display is used instead of the lamp.