JP2005312224A - Battery charging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery charging apparatus for preventing temperatures of a battery liquid, a transformer and a rectifying section from excessively rising in a boosting charge mode, and stably ensuring the required quantity of electricity to be supplied during the boosting charge. <P>SOLUTION: The battery is constituted so as to be charged in one charge mode selected from a normal charge mode for charging the battery by a predetermined charging current and the boosting charge mode for rapidly charging the battery by the charging current higher than the predetermined charging current. The quantity of electricity charged during the boosting charge since the charging starts in the boosting charge mode, is found as a current integration value (S34). When the found integration value becomes a preset current integration value limit or more during the rapid charging in the boosting charge mode, a boosting charge period is terminated (S35). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery charging device, and more particularly to a battery charging device for battery-powered electric vehicles.

  Conventionally, a battery charging device for charging a battery mounted on an industrial electric vehicle such as an electric forklift has a quasi-constant voltage charging method configured by a rectifier circuit of a transformer and a diode bridge without controlling a charging current. Often a container. However, in the case of a battery charging device that controls the charging current, a normal charging mode having a normal charging period in which a relatively low current is supplied to the battery for charging, and a charging current larger than that in the normal charging mode are supplied to the battery. There is a configuration in which either one of a quick charge mode having a quick charge period in which quick charge is performed in a short period of time can be selected. In the normal charging mode, charging is performed with a relatively small charging current, so that charging can be performed while suppressing a rapid increase in the liquid temperature of the battery, but the charging time until complete charging is increased. On the other hand, the quick charge mode is selected when, for example, the battery discharge amount when a forklift or the like is used during work hours is replenished during a break time. In the quick charge mode, the battery can be charged in a short time by supplying a larger charge current to the battery than in the normal charge mode.

  If such a battery charging device is used, for example, after the end of the day, the battery is fully charged until the next morning in the normal charging mode, while the battery is charged in the quick charging mode during breaks such as lunch breaks. Can be quickly charged to compensate for the amount of discharge in the previous work.

  By the way, many of the battery charging devices described above are charged by a constant current / constant voltage method. In this constant current / constant voltage method, a relatively large constant charging current is supplied to the battery in the initial stage of charging, and when the battery voltage reaches a predetermined voltage (for example, a battery inversion voltage), By maintaining the battery voltage at the predetermined voltage, the charging current is gradually reduced for charging. In addition, a two-stage constant current / constant voltage method capable of suppressing the charging current immediately before the completion of charging is also employed.

  However, in the quick charge mode, the charge current is larger than that in the normal charge mode, and a considerably large charge current is supplied to the battery at the beginning of charge. There is a risk that the temperature of the transformer, the rectifying unit, and the like in the apparatus will rise excessively. In particular, when performing quick charging with the above-described constant current / constant voltage method or two-stage constant current / constant voltage method, a large charging current is supplied to the battery from the start of charging until a predetermined voltage is reached, The temperature of the battery or the battery charger increases. Furthermore, constant voltage charging is performed after the battery voltage reaches a predetermined voltage, so that depending on conditions such as charging current and charging time, the electrode plate may deteriorate due to an increase in battery liquid temperature, resulting in battery life. May decrease. Also, in order to prevent the temperature of the transformer, rectifier, etc. in the battery charging device from rising excessively, it is necessary to dissipate the generated heat more effectively, and the structure of the battery charging device becomes complicated. Or it will enlarge.

Therefore, in the quick charge mode, when charging with a constant charging current from the start of charging, even if the battery voltage has not reached the predetermined voltage, if the predetermined time has elapsed since the start of charging, A configuration in which the charging current is reduced by switching to the normal charging mode has been proposed (see Patent Document 1).
Further, as a quick charging device for an electric golf cart, there is also known a device that stops charging when a predetermined time has elapsed from the start of charging even when the battery voltage has not reached a predetermined voltage during quick charging. (See Patent Document 2).

JP-A-2002-191136 (page 5-7, FIG. 2, FIG. 4) JP 2002-315216 A (5th page, FIG. 5 and FIG. 7)

In the battery charging devices described in Patent Literature 1 and Patent Literature 2 described above, rapid charging is performed only for a certain period of time. Therefore, if the certain time is set short, the battery charging device has a longer time than that when a long time is set. It is possible to prevent the temperature of the transformer and the like and the temperature of the battery fluid from rising.
However, for example, there is another device connected to the external power source to which the battery charging device is connected, and an excessive load is temporarily generated in the device, and the external power source is temporarily cut off due to an overcurrent. In some cases, the current supplied from the external power supply may temporarily decrease. In such a case where the supply current temporarily decreases, the battery cannot be charged with the set charging current during the rapid charging. For this reason, there is a possibility that the normal charge mode may be switched or the charging may be stopped without securing the necessary amount of electricity to be supplied in the rapid charging.

  The present invention has been made in view of the above circumstances, and should suppress the battery liquid temperature, the temperature of the transformer, the rectifying unit, and the like from rising excessively even in the quick charge mode, and be supplied by rapid charge. It is an object of the present invention to provide a battery charger capable of stably securing a necessary amount of electricity.

Means for Solving the Problems and Effects of the Invention

  According to a first aspect of the present invention, there is provided a battery charging apparatus connected to an external power source, in a normal charging mode having a normal charging period for charging the battery with a predetermined charging current, and for rapidly charging the battery with a charging current larger than the predetermined charging current. A battery charging device capable of charging a battery in one of the charging modes selected from the quick charging mode having a quick charging period, wherein the battery is being rapidly charged after charging in the quick charging mode is started Current integrating means for obtaining the amount of electricity charged as an integrated value of current, and an integrated current amount in which the integrated value obtained by the current integrating means during quick charging in the quick charge mode is a preset value. And a quick charge end means for ending the quick charge period when the limit value is exceeded.

  According to this configuration, the amount of electricity charged during rapid charging is obtained as an integrated value of current, and when this integrated value is equal to or greater than a preset current integrated amount limit value, the rapid charging period is terminated. become. For this reason, it can suppress that the temperature of the trans | transformer etc. in a battery charging device, or the temperature of battery liquid rises excessively according to the method of setting an electric current integration amount limit value. And even if the case where the current supplied from the external power source temporarily decreases by setting the current integrated amount limit value according to the necessary amount of electricity to be supplied by quick charging, Unless there is another factor such as stopping the quick charge because the battery voltage has reached a predetermined voltage, the quick charge is continued until a necessary amount of electricity to be supplied in the quick charge is secured. Accordingly, even in the quick charge mode, it is possible to suppress excessive rise in the battery liquid temperature, the temperature of the transformer, the rectifying unit, and the like, and to stably secure a necessary amount of electricity to be supplied by the quick charge. .

  According to a second aspect of the present invention, in the battery charger according to the first aspect, the current integrating means integrates a value obtained by a product of a current value detected every preset unit time and the unit time. The integrated value is calculated by following the calculation.

  According to this configuration, the amount of electricity charged during the quick charge can be easily calculated by integrating the product value of the current value detected per unit time and the unit time.

  Embodiments of the present invention will be described. This embodiment is an example in which the present invention is applied to a battery charging device that charges a battery of an electric forklift. The present invention can be applied even when used as a battery charger that charges a battery other than the battery of the electric forklift, and can be applied to a wider range of uses.

First, the battery charger 1 will be briefly described with reference to FIG.
As shown in FIG. 1, in the battery charger 1, a three-phase AC power source 2 as an external power source is connected to a thyristor, a transistor, or the like via a power plug 3, an electromagnetic switch 4 that performs on / off control, and a transformer 5. The configured rectifying unit 6 is connected. Then, both end electrodes of the battery 7 are connected to the rectifying unit 6, and the battery 7 is charged by the output from the rectifying unit 6.

  The battery voltage V of the battery 7 is detected by a voltage detection unit 8 connected to both end electrodes of the battery 7, while the charging current I supplied to the battery 7 is detected by a current sensor 9. And this battery charging device 1 controls the rectification | straightening part 6 by the controller 10 based on the detection signal from the voltage detection part 8 and the current sensor 9, and connects between the three-phase alternating current power supply 2 and the battery 7 suitably. The battery 7 is charged by controlling the battery voltage V and the charging current I by shutting off. Furthermore, as will be described later, the battery charging device 1 has a normal charging mode in which a normal charging period for supplying a relatively low predetermined charging current to the battery 7 is performed for a long period (for example, 8 hours or more) of normal charging. And a quick charge mode having a period of rapid charge for a short time (for example, about 1 hour) as a quick charge period for supplying a charge current larger than a predetermined charge current to the battery 7 in the normal charge mode, The battery can be charged in one of the charging modes selected from the above.

  The controller 10 includes a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The ROM controls a battery voltage V and a charging current I. Control program for performing battery charging processing (see FIGS. 2 to 4) to be described later for charging the battery 7, and setting voltage V1, current values I1, I2 and setting time T1 used in the battery charging processing. In addition, data of various set values such as the current integrated amount limit value AH1 is stored. As shown in FIG. 1, the controller 10 is connected to a normal charge switch 11 for selecting a normal charge mode and a quick charge switch 12 for selecting a quick charge mode. When any one of the quick charge switches 12 is operated, charging of the battery 7 is started in a charge mode corresponding to the operated switch.

  Therefore, for example, after the end of the day when the use of the forklift is finished, the power plug 3 is connected to the three-phase AC power source 2 and then the normal charging switch 11 is operated, and the battery 7 is completely discharged until the next morning in the normal charging mode. On the other hand, during the break time such as lunch break, it is possible to operate the quick charge switch 12 to rapidly charge the battery 7 in the quick charge mode to compensate for the discharge amount in the previous work. .

  In the controller 10, the CPU, the control program in the ROM, the RAM, and the like are combined to perform various functions in battery charging processing described later (various functions described with reference to FIGS. 2 to 7). Each part is built. And as a part of such a part, the current integration part (current integration means) 13 and the quick charge end part (rapid charge end means) 14 are provided.

  The current integrating unit 13 calculates the amount of electricity charged during the rapid charging after the quick charging switch 12 is operated and the charging in the rapid charging mode is started as the integrated value AH of the current. Specifically, a value (I × T0) obtained by the product of the current value I detected by the current sensor 9 at each preset time T0 (for example, T0 = 1 second) and the unit time T0. Is integrated (integrated the detected current value I every unit time T0) to calculate the integrated value AH.

  In addition, the quick charge end unit 14 determines that the quick charge end unit 14 is quick when the integrated value obtained by the current integrating unit 13 is equal to or greater than a current integrated amount limit value AH1 that is a preset value during the quick charge in the quick charge mode. Terminate the charging process. In the controller 10, the current integrated amount limit value AH1 can be set to a desired value as appropriate, and the current integrated amount limit value is set according to the necessary amount of electricity to be supplied by rapid charging. This can be set arbitrarily. In the battery charging device 1, when the quick charging process is ended by the quick charging end unit 14, the normal charging process is automatically started as described later.

Next, battery charging processing by the battery charging device 1 of the present embodiment will be described with reference to the flowcharts of FIGS. 2 to 4 and FIGS. 5 to 7. In the following description, Si (i = 10, 11, 12,...) Indicates each step i.
As shown in FIG. 2, when the normal charging switch 11 is operated (S11: YES) with the power plug 3 connected to the three-phase AC power source 2 (S10: YES), the normal charging in step 14 is performed. The process is executed and the battery 7 is charged in the normal charging mode. In this normal charging process, the battery 7 is charged by a constant current / constant voltage method as shown in FIG. This constant current / constant voltage method is a general charging method and will be described briefly.

  As shown in FIGS. 3 and 5, in this normal charging process, at the initial stage of charging, the battery 7 is charged with a constant charging current I1 (S20, S21), and the battery voltage V is increased as the constant current charging proceeds. Rises. When the battery voltage V detected by the voltage detection unit 8 reaches the set voltage V1 (S20: NO), switching to constant voltage charging (S22) is performed, and the battery voltage V is maintained at the preset set voltage V1. The battery 7 is charged in the state. The set voltage V1 can be arbitrarily set, for example, can be set in consideration of the inversion point voltage or the like. When this constant voltage charge (S23) proceeds and the time from the start of constant voltage charge reaches a preset charge end time T1 (S23: YES), the process returns to the main routine of FIG. Exit. The period during which the battery is charged with a predetermined charging current I1 is the normal charging period.

  On the other hand, in FIG. 2, when the quick charge switch 12 is operated (S12: YES), the quick charge process of step 13 (process of FIG. 4) is executed and the battery 7 is charged with a charge current larger than that in the normal charge mode. Is charged quickly. In this rapid charging process, as shown in FIG. 6, the battery 7 is charged by a constant current / constant voltage method.

  4 and 6, when the quick charging process is started, first, the current integration process for obtaining the integrated value AH is started by the current integrating unit 13, and the initial value of the integrated value AH is first set to 0. (S30). Subsequently, constant current charging is performed (S31). In the constant current charging, the battery 7 is supplied with a charging current I2 that is larger than the charging current I1 during the normal charging period in the normal charging mode to perform rapid charging. The period during which constant current charging is performed with this charging current I2 is the rapid charging period. In the quick charge period, it is determined whether or not the unit time T0 has elapsed while continuing the quick charge (charging with the charging current I2).

  If it is determined that the unit time T0 has elapsed since the start of current integration (S30) (S32: YES), then whether or not the battery voltage V detected by the voltage detector 8 is less than the set voltage V1. Is determined (S33). Similarly, when it is determined in step 35 described later that the integrated value AH is less than the current integrated amount limit value AH1 (S35: NO), after it is determined that the integrated value AH is less than the current integrated amount limit value AH1. If it is determined that the unit time T0 has elapsed (S32: YES), it is determined whether or not the battery voltage V is less than the set voltage V1 (S33).

  If it is determined in step 33 that the battery voltage V has not yet reached the set voltage V1 (S33: YES), the stored content of the value of the integrated value AH is updated to the value of the integrated value AH so far. On the other hand, the product value (I × T0) of the current value I detected by the current sensor 9 and the unit time T0 is further added (integrated), and a new integrated value AH is calculated and stored. (S34). Next, it is determined whether or not the integrated value AH newly calculated in step 34 is equal to or greater than the current integrated amount limit value AH1 (S35). If it is determined in step 35 that the integrated value AH is less than the current integrated amount limit value AH1 (S35: NO), the processing from step 31 onward is repeated again. On the other hand, when it is determined that the integrated value AH is equal to or greater than the current integrated amount limit value AH1 (S35: YES), the quick charge process is terminated, that is, the process shown in FIG. 4 is terminated and the main routine of FIG. Return to Subsequently, the normal charging process of step 14 is performed. In this case, the relationship between the charging current I and the battery voltage V and the charging time is as shown in FIG. That is, after the quick charging is performed with the charging current I2 and the integrated value AH reaches the current integrated amount limit value AH1, the normal charging period with the charging current I1 is started. Then, after the battery voltage V reaches the set voltage V1, constant voltage charging is performed.

  When it is determined in step 33 that the battery voltage V is equal to or higher than the set voltage V1 (S33: NO), that is, when the battery voltage V reaches the set voltage V1, the above-described normal charging process is performed. Similarly, switching to constant voltage charging (see FIG. 6), the battery 7 is charged with the battery voltage V maintained at the set voltage V1 (S36). When the constant voltage charging proceeds and the time from the start of constant voltage charging reaches a preset charging end time T1 (S37: YES), the process returns to the main routine of FIG. 2 to end the charging.

  According to the battery charging device 1 described above, the amount of electricity charged during the rapid charging is obtained as the integrated value AH of the current, and when this integrated value AH becomes equal to or greater than the preset current integrated amount limit value AH1, The quick charge period will be terminated. For this reason, it can suppress that the temperature of the trans | transformer etc. in the battery charging device 1 or the temperature of a battery liquid rises excessively according to the method of setting the electric current integration amount limit value AH1. And even if the case where the electric current supplied from an external power supply falls temporarily by setting electric current integrated amount limit value AH1 according to the required electric quantity which should be supplied by quick charge occurs. Unless the battery voltage V reaches the set voltage V1 and there are other factors that stop the rapid charge, the rapid charge is continued until the necessary amount of electricity to be supplied in the rapid charge is secured. Become. Accordingly, even in the quick charge mode, it is possible to suppress excessive rise in the battery liquid temperature, the temperature of the transformer, the rectifying unit, and the like, and to stably secure a necessary amount of electricity to be supplied by the quick charge. . Also, by calculating the integrated value AH by integrating the product value of the current value I and the unit time T0 detected every unit time T0, the amount of electricity charged during the quick charge can be easily calculated. Can do.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, the following modifications may be made.

(1) In the present embodiment, description has been given of switching from the rapid charging current to the normal charging current when the integrated value becomes equal to or greater than the current integrated amount limit value, but the present invention is not limited to this. For example, charging may be performed by switching to a current value equal to or lower than the charging current value for normal charging. Further, after switching to the current value and charging for a certain period of time, it may be further switched to the charging current of normal charging.

(2) In the present embodiment, the calculation of the integrated value has been described as integrating the product of the current value detected per unit time and the unit time, but this need not necessarily be the case. For example, the unit time may be fixed to 1 second, and integration may be performed so that the current value is simply added every second.

(3) In the present embodiment, the case of the battery charging device adopting the constant current / constant voltage method has been described as an example, but other methods may be used. For example, as shown in FIG. 8, the present invention can also be applied to a battery charging apparatus that employs a so-called two-stage constant current / constant voltage system that can suppress a charging current at the end of charging.

(4) In this embodiment, the battery charging device for charging the battery of the electric forklift has been described as an example. However, the present invention can also be applied to a battery charging device for a battery-powered electric vehicle other than the forklift. .

1 is a schematic circuit diagram illustrating a battery charging device according to an embodiment of the present invention. It is a flowchart of the main routine of the battery charge process in the battery charging device shown in FIG. It is a flowchart of the normal charge process in the battery charge process shown in FIG. It is a flowchart of the quick charge process in the battery charge process shown in FIG. It is explanatory drawing explaining the time change of the battery voltage and charging current in the normal charging mode of a constant current / constant voltage system. It is explanatory drawing explaining the time change of a battery voltage and a charging current in case a battery voltage reaches | attains a setting voltage during quick charge. It is explanatory drawing explaining the time change of a battery voltage and charging current when a battery voltage does not reach a setting voltage during quick charge. It is explanatory drawing explaining the time change of the battery voltage and charging current in the normal charging mode of the two-stage constant current / constant voltage method according to the modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery charger 2 Three-phase alternating current power supply 3 Power plug 7 Battery 10 Controller 13 Current integration part (current integration means)
14 Quick charge end part (Quick charge end means)

Claims (2)

A normal charging mode connected to an external power source and having a normal charging period for charging the battery with a predetermined charging current; and a quick charging mode having a quick charging period for rapidly charging the battery with a charging current larger than the predetermined charging current; A battery charging device capable of charging a battery in one of the charging modes selected from
Current integrating means for determining the amount of electricity charged during rapid charging after charging in the quick charging mode as an integrated value of current;
During the quick charging in the quick charge mode, when the integrated value obtained by the current integrating means becomes equal to or greater than a current integrated amount limit value that is a preset value, the quick charging is terminated to end the quick charging period. Means,
A battery charging device comprising:   The said current integration means calculates the said integration value by integrating | accumulating the value calculated | required by the product of the electric current value detected for every preset unit time, and the said unit time. The battery charger according to 1.

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