JP4007945B2 - Charging method and program thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a charging method and a program therefor, in which initial charging is performed with a relatively large constant current to make it close to full charging, and then terminal charging is performed with a small constant current to end charging.
[0002]
[Prior art]
For example, when charging a lead-acid battery with a relatively large constant current, a large amount of oxygen gas is generated at the positive electrode at the end of charging or overcharging, and the amount of water in the electrolyte decreases because it cannot be sufficiently reduced to water. Battery life is shortened. Further, when the amount of charge is reduced to suppress the decrease in the amount of water in the electrolyte, the amount of charge is insufficient, the negative electrode is deteriorated, the charge / discharge reaction hardly occurs, and the battery life is shortened.
From this point, for example, as shown in Patent Document 1, the battery is charged to a state near full charge with a relatively large constant current, and then the terminal charge is performed until the total charge amount becomes 110% of the discharge amount with a small constant current. It has been proposed to do.
[0003]
[Patent Document 1]
Paragraphs [0019] to [0022] of Japanese Patent Laid-Open No. 2001-339871
[0004]
[Problems to be solved by the invention]
In the conventional charging method, the charging is completed when the terminal charging is completed. After the end of charging, the battery is discharged slightly due to the leakage current of the equipment, etc., so if the storage battery is not used for a long time after the end of charging, the equipment operated by the power of the storage battery can be operated sufficiently. Therefore, for example, the storage battery is in a state of requiring charging without being operated for the scheduled time. Further, if the time until use after charging is long, the temperature of the electrolytic solution of the storage battery is too low to supply sufficient power.
[0005]
Further, in the past, the current value of the terminal charge has been a constant value of 1A, for example. According to this current value, the terminal charge period is short, but the temperature of the electrolyte of the storage battery rises by about 15 ° C. for each terminal charge, and the temperature of the electrolyte of the storage battery is about an average of one day. Decrease by 10 ° C. Therefore, for example, if a device that operates with the power of this storage battery is used every day and charged every day, the electrolyte temperature will be cumulatively increased by about 5 ° C. every day, the electrolyte temperature will become too high, and the storage battery will deteriorate. .
An object of the present invention is to provide a charging method and program for completing charging at a set time or a set time without deteriorating the storage battery.
[0006]
[Means for Solving the Problems]
According to the present invention, the terminal charge time is obtained from the time from the start time of the terminal charge to the set end time or the value obtained by subtracting the initial charge time from the set charge time. The charging current value at the end of charging is determined from the amount of charge required for charging.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The procedure of the embodiment of the present invention is shown in FIG. As shown in FIG. 2, the charger to which the method of the present invention is applied is, for example, supplied with AC power from a commercial three-phase AC power supply 11 to the full-wave rectification unit 12, and the DC-DC conversion of the full-wave rectification unit 12. The unit 13 converts DC power. For example, the output of the full-wave rectification unit 12 is converted into high-frequency AC power by the inverter 14, and this high-frequency AC power is boosted by the transformer 15 and supplied to the rectification unit 16. The DC power from the rectifying unit 16 is supplied to the storage battery 18 through the current detection unit 17, and the storage battery 18 is charged. The inverter control unit 19 controls the switching width of the inverter 14 with respect to the switching element so that the charging current is detected by the current detection unit 17 and the charging current becomes a set value.
[0008]
The voltage (charge voltage) Vc of the storage battery 18 is detected by the voltage detection unit 21, and the detected battery voltage Vc rises with the progress of charging. When the battery voltage Vc reaches a predetermined voltage Vf, the voltage detection unit 22 is detected. The predetermined voltage Vf is often a voltage that is assumed to be an inflection point in the rising curve of the battery voltage Vc. However, the predetermined voltage Vf is not necessarily the inflection point voltage, and may be an appropriate value that is, for example, less than the inflection point voltage. There is no need to fix the exact value. Charging control of the entire charger is performed by the main control unit 23, and various displays are displayed on the display unit 24. The charging operation is started by the start setting unit 25 such as a start switch. A clock 26 for outputting time and a work storage unit 27 are provided. The predetermined voltage Vf is set in the predetermined voltage detector 22.
[0009]
In this embodiment, an end time setting unit 31 is provided so that the time at which charging is to be ended can be set. As the end time setting unit 31, various devices such as a digital switch, a keyboard switch, and an input means using a computer such as a mouse can be used. Further, an initial charge amount calculation unit 32, an end-stage charge time calculation unit 33, and an end-stage current calculation unit 34 are provided.
An embodiment of the method of the present invention will be described with reference to FIG. It is checked whether this charger is connected to the AC power supply 11 (step S1). If it is connected, it is checked whether the charging start setting is made in the setting unit 25, for example, whether the start switch is turned on (step S2), When the start setting is made, the battery 18 starts initial charging with a constant current (step S3). Charging is performed at a constant current Ii of 80 A in a large current within a range allowed for the storage battery 18, for example, a 400 Ah battery. That is, the inverter control unit 19 controls the inverter 14 so that such a constant current Ii is supplied to the storage battery 18. Further, in order to detect the initial charging time, for example, the charging start time ts is stored in the storage unit 27 (step S4).
[0010]
The predetermined voltage detector 22 checks whether the battery voltage Vc has reached the predetermined voltage Vf (step S5). As shown in FIG. 3, the battery voltage Vc rises when charging is started, and when it becomes relatively close to full charge, an inflection point Pf occurs in the rising curve 36 of the battery voltage Vc with respect to the charging time. Is the inflection point voltage in the so-called charging rise curve 36. When it is detected that the battery voltage Vc has reached a predetermined voltage Vf, for example, a predetermined voltage assumed to be an inflection point voltage, it is checked whether an end time is set (step S6).
[0011]
If the end time is set, the terminal charge time calculator 33 calculates the terminal charge time Te (step S7). That is, the end time te set from the end time setting unit 31 is read out, and the difference te-tf between this and the current time tf read out from the clock 26 is calculated to obtain the terminal charge time Te. The terminal charge current Ie is calculated by the terminal current calculator 34 based on the terminal charge time Te and the amount of charge from the start of charging to the present (S8). That is, by subtracting the charging start time ti in the storage unit 27 from the current time tf to obtain the time Ti for which the initial charging was performed, the initial charging time Ti is multiplied by the charging current Ii in the initial charging to thereby charge the initial charging amount. Find Wi. This initial charge amount Wi is generally and empirically known to be about 80 to 90% of full charge. In addition, it is considered to be charged to about 105 to 120% of full charge. Therefore, for example, assuming that 80% of the full charge is charged by the initial charge, and the charge is 110% of the full charge by the end charge, the charge amount by the end charge is (30/80) × Wi, and the charging current in the end charge Ie is a value obtained by dividing (30/80) × Wi by the terminal charge time Te, ie, Ie = (30/80) × Wi / Te. This terminal charge current Ie is calculated by the terminal current calculator 34.
[0012]
It is checked whether or not the calculated end charging current value Ie is equal to or less than the upper limit value Ieu of the end current (step S9), that is, the calculated current value Ie is equal to or less than the maximum charging current value Ieu allowed for the storage battery 18 as end charging. If there is, the charging current for the storage battery 18 is changed to the calculated terminal charging current value Ie to start terminal charging (step S10). That is, the inverter control unit 19 controls the inverter 14 so that the charging current becomes equal to the terminal charging current value Ie. In this state, the system waits for the set end time te (step S11), and ends the charging process when the end time te is reached (step S12).
[0013]
In the charging of this embodiment, as shown by the rising curve 36 in FIG. 3, when the initial charging period Ti is charged with a constant current Ii and the battery voltage Vc reaches the predetermined voltage Vf, if the setting end time is te ₁ If the constant current Ie ₁ is the last charge for the time Te ₁ and the setting end time is te ₂ , the constant current Ie ₂ is the last charge for the time Te ₂ . In this case, the charge amount of the terminal charge is the same at any setting end time. That is, Te ₁ × Ie ₁ = Te ₂ × Ie ₂ . In the above example, (30/80) Ii × Ti = Te ₁ × Ie ₁ is set. Thus, if the setting end time is set late, the charging current Ie for the terminal charge becomes small.
[0014]
In step S9, if the calculated end-stage current value Ie is not less than or equal to the upper limit value Ieu, the end-stage current is set to the upper limit value Ieu and end-stage charging is started (step S13). The extension end time ted is calculated (step S14). In other words, the charging time Tu = (30/80) Wi / Ieu is obtained so that the charging amount (30/80) Wi required for the terminal charging is equal to the charging amount IeuTu charged in the charging time Tu by the current Ieu, and the predetermined voltage Vf The time obtained by adding the charging time Tu to the time tf at which the time becomes the extension end time ted. Until this extension end time ted is reached (step S15), the terminal charge is performed with the constant current Ieu and the charging is ended (step S12).
[0015]
If the end time te is not set in step S6, the terminal charging is performed for a predetermined time with the terminal charging current upper limit Ieu (step S16), and the charging is ended (step S12). In general, the predetermined time at this time is determined according to the initial charging time Ti, for example, a value obtained by adding a predetermined small time to a half of the initial charging time Ti.
In the above description, instead of setting the charging end time te, a charging time, that is, a time Tc from the start of charging to the end of charging may be set. In this case, in step S7, the terminal charge time Te is calculated by setting the initial charge time Ti to the remaining value Te = Tc−Ti obtained by subtracting the set charge time Tc. In step S11, Te is added to the time tf at which the predetermined voltage Vf is reached. The time may be set as the end time te, wait until the end time te is reached, or time Te may be set in the timer, and charging may be terminated when the timer times out. In the latter case, the timer 26 can be omitted by starting the count of the timer at the start of charging and obtaining the initial charging time Ti from the count value of the timer when the voltage reaches the predetermined voltage Vf. Even when the clock 26 is used, the initial charging time Ti may be obtained by a timer.
[0016]
The constant current in the initial charging is not necessarily kept constant during the initial charging time Ti, and the constant current value may be decreased appropriately and stepwise as shown in Patent Document 1, for example. Alternatively, a discharge amount during operation of a device that uses the power of the storage battery 18 may be obtained, and this discharge amount may be used as the charge flow Wi in the initial charge. The present invention can be applied not only to three-phase AC power but also to rectifying and charging single-phase AC power.
The charger shown in FIG. 2 can also be operated by a computer. In this case, a charging program for causing the computer to execute the steps shown in FIG. 1 can be downloaded from a recording medium such as a CD-ROM or a magnetic disk or via a communication line to the computer and executed. That's fine.
[0017]
【The invention's effect】
As described above, according to the present invention, since the charging end time or time can be set, the charging can be ended slightly, for example, one hour before using the storage battery next time. Therefore, the amount of spontaneous discharge from the end of charging to use can be made sufficiently small, it can be used as a storage battery with a sufficient amount of charge, and a predetermined capacity can be output without excessively decreasing the temperature of the electrolyte. can do.
In addition, in general, the time to stop using the battery and stop using it again is often very different. In such a case, when the time from the stop to the reuse is long, The constant current value Ie is considerably smaller than the upper limit value Ieu. Therefore, the rise of the electrolyte is slightly or negligible due to the end-stage charging, and the temperature of the electrolyte rises more than necessary, and there is no risk of shortening the life. .
[Brief description of the drawings]
FIG. 1 is a flowchart showing an embodiment of the present invention.
FIG. 2 is a diagram showing a functional configuration example of a charger to which the method of the present invention is applied.
FIG. 3 is a diagram showing a change characteristic example of a storage battery voltage from the start of charging.

Claims (2)

A charging method in which the charging end time or charging time can be set and the battery is charged by initial charging and terminal charging,
The terminal charge time calculation step for calculating the terminal charge time from the initial charge end time or the initial charge time,
A terminal charge current calculation step for calculating a terminal charge current from the charge amount of the initial charge and the terminal charge time,
A terminal current comparison step for comparing the calculated terminal charging current and a predetermined upper limit of the terminal current;
If the terminal charge current is less than or equal to the upper limit of the terminal current, a first terminal charge step of performing terminal charge until a set charge end time or until a set charge time ends;
If the terminal charge current is greater than the upper limit of the terminal current, the terminal current upper limit is the terminal charge current, the charge end time or terminal charge time is calculated from the initial charge amount and the terminal current upper limit. A second terminal charging step for performing terminal charging until the charging end time or until the calculated terminal charging time ends;
Charging method to have a. A program for causing a computer to execute each step of the charging method according to claim 1.

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