JPH04351432A - Automatic charger - Google Patents

Abstract

PURPOSE:To suppress temperature rise of electrolyte at the time of additional uniform charging by providing a pause before starting additional uniform charging after normal charging. CONSTITUTION:During uniform charging, battery voltage varies as shown by a curve 31 whereas charging current varies as shown by a curve 34. Temperature of electrolyte in the battery increases gradually as shown by a curve 35 upon start of charging operation, especially the temperature increases relatively sharply at an inflection point Pi. A pause interval T2 is provided after finish of normal charging operation in order to lower the electrolyte temperature and additional charging is carried out after the pause interval T2. Since the temperature of electrolyte lowers during the pause interval and the gas ascends from around the electrode, temperature rise of electrolyte is suppressed. Consequently, the battery is prevented from deteriorating, service life thereof is prolonged resulting in efficient charging operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic charging device that selectively performs normal charging and equal charging of a storage battery.

0002

2. Description of the Related Art Conventionally, there are two types of charging for storage batteries: normal charging and equal charging. In normal charging, when the voltage of the storage battery reaches the inflection point after charging is started, the battery is charged again for a certain period of time, or for a period corresponding to the time from the start of charging until reaching the inflection point, and then the charging is completed. do.

[0003] When normal charging is repeated, differences in performance arise between each cell of the storage battery. For this reason, equal charging is performed every time normal charging is performed an appropriate number of times. In equal charging, after the inflection point in normal charging is reached, charging is performed for a longer time than in normal charging, that is, charging is performed with a slight overcharging to equalize the performance of each cell.

0004

[Problems to be Solved by the Invention] In uniform charging, as the temperature of the electrolyte increases and the voltage increases at the end of charging, more water electrolysis occurs and hydrogen gas and oxygen gas are generated. As a result, the area around the electrode is covered with bubbles, which reduces the surface area of the electrode in contact with the electrolyte, reducing charging efficiency. Hydrogen gas and oxygen gas are more likely to be generated, which tends to increase the amount of electrolyte. To compensate for this, the frequency of water replenishment increases, but if the timing of water replenishment is delayed, it may cause damage to the storage battery. The generation of gas also shortens the lifespan of storage batteries.

[0005]

[Means for Solving the Problems] According to the present invention, equal charging includes means for performing normal charging, suspending means for suspending charging after the termination of the regular charging, and additional charging for performing additional charging after the halt. It is carried out by means.

[0006]

Embodiment FIG. 1 shows an embodiment of the present invention. This automatic charging device is connected to an AC power source 12 such as a commercial power source through an outlet 11, for example. Switch 13 on outlet 11
is connected to the AC power supply 1 inputted through the switch 13.
The AC power of No. 2 is set to an appropriate voltage by a transformer 14, converted to DC power by a rectifier 15, and supplied to a storage battery 16 to charge the storage battery. A power supply circuit 17 is connected to the storage battery 16, and operating power is supplied from the power supply circuit 17 to each part.

An AC detection circuit 18 is connected to the outlet 11, and when the outlet 11 is connected to the AC power supply 12, the AC power from the AC power supply 12 is detected by the AC detection circuit 18, and this detection output is sent to the control section 19 consisting of a CPU. is notified, and the control unit 19 learns that this automatic charging device is connected to the AC power source 12. The control unit 19 is the interface 2
1, the switch 13 can be controlled on and off.
Further, the voltage of the storage battery 16 is detected by the voltage detection circuit 22 and notified to the control unit 19, and the control unit 19 can perform normal charging, equal charging, etc. The normal charging switch 23 and the equal charging switch 24 are connected to the control unit 19, and the control unit 19 can control the lighting of the equal charging display element 26, the normal charging display element 27, and the completion display element 28 through the interface 25. These display elements 26
As ~28, for example, a light emitting diode is used.

Next, the operation of this device will be explained with reference to the flowchart of FIG. When the operation starts, first, it waits for the AC power supply 12 to be connected to the outlet 11 (S1), and when AC power is input and this is detected, the normal charging switch 23 is turned on. If it is not turned on, it is checked whether the equal charging switch 24 is turned on (S3), and if it is not turned on, the process returns to step S2. In other words, it waits for either switch 23 or 24 to be turned on.

When the normal charging switch 23 is turned on,
Moving from step S2 to step S4, the normal charging display element 27 is lit, and normal charging is further performed (S5)
. As is well known, in normal charging, charging of the storage battery 16 is started by turning on the switch 13, and this charging is carried out at a constant current.During this charging, the voltage of the storage battery 16 is monitored, and as shown in FIG.
As shown in a curve 31, when the storage battery voltage reaches an inflection point P1, constant voltage charging is performed and the charging current is reduced. This constant voltage charging period T1 is either a predetermined fixed time or a time determined by the time from the start of charging until reaching the inflection point P1, and the constant voltage charging period T1 ends. Then, the switch 13 is turned off to end normal charging. When charging is completed, the completion display element 28 is turned on and the process ends (S6).

When it is detected in step S3 that the equal charging switch 24 is turned on, the process moves to step S7, where the equal charging display element 26 is turned on, and then normal charging is executed (S8). This normal charging is the same operation as the normal charging in step S5, so when this normal charging is finished, the switch 13 is turned off and charging is stopped. Simultaneously with this stop, the timer 32 in the control unit 19 is started (
S9), and waits for the timer 32 to time up (S10). When the set time T2 of the timer 32 elapses and the time is up, additional charging is performed (S11).

That is, the timer 33 in the control unit 19 is started (S11a), and at the same time, the switch 13 is turned on and charging of the storage battery 16 is resumed (S11b).
). When the set time T3 of the timer 33 has elapsed, that is, the timer 33 times up (S11c), the switch 13 is turned off and the additional charging ends (S11d). At the same time, the completion display element 28 is lit and the process ends (S12).
.

The voltage of the storage battery 16 during equal charging is shown in FIG.
The charging current changes as shown by curve 31, and the charging current changes as shown by curve 34. As shown in the curve 35, the temperature of the electrolyte in the storage battery 16 gradually rises with the start of charging, especially at the inflection point P.
It rises relatively rapidly from 1. In this way, at the end of normal charging, the liquid temperature becomes quite high and gas is generated.
In the past, during equal charging, additional charging was performed immediately after normal charging, making the liquid temperature even higher and generating more gas.

However, in the present invention, in equal charging, a rest period T2 is provided after the end of normal charging, and this rest period T2
Since the liquid temperature is lowered at , and then additional charging is performed, there is no risk of the liquid temperature becoming too high, and there is little gas generation.
In addition, the gas around the electrode rises during the rest period, and the electrode is no longer surrounded by gas, so that charging efficiency does not decrease. The rest period T2 is determined by the temperature rise during the additional charging period (usually the temperature rise is about 1°C/hour), based on the length of the additional charging period.
In consideration of this, the liquid temperature is set so as to be lowered so as not to reach a temperature that would significantly deteriorate the storage battery during the additional charging time. T2 is, for example, about 1 to 2 hours. Additional charging may be performed after the liquid temperature is detected and the liquid temperature becomes below a predetermined value.

[0014] The rest period T2 may be divided, and the additional charging may also be divided and carried out multiple times. An additional charging switch may be provided in place of the equal charging switch 24, and when performing equal charging, both the normal charging switch 23 and the additional charging switch may be turned on. That is, after step S5 in FIG. 2, it may be checked whether the additional charging switch is turned on.

[0015]

As described above, according to the present invention, during equal charging, after normal charging, a rest period is provided and additional charging is performed, so that the temperature of the electrolyte decreases during the rest period, and the temperature around the electrodes decreases. gas rises and there is no gas in the surrounding area. Therefore, during the additional charging period, there is no risk of the temperature of the electrolyte becoming too high, there is less water decomposition, less frequent refilling of water, less deterioration of the storage battery, longer life, and more efficient charging. be exposed.

[Brief explanation of the drawing]

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

FIG. 2 is a flowchart illustrating an example of the operation of the apparatus of FIG. 1;

FIG. 3 is a diagram showing examples of changes in charging voltage, charging current, and electrolyte temperature.

Claims (1)

[Claims] Claim 1: An automatic charging device configured to selectively perform normal charging and equal charging, wherein the equal charging comprises means for performing the normal charging, and a pause for suspending charging after the normal charging is completed. An automatic charging device comprising: means; and an additional charging means that performs additional charging after stopping the automatic charging means.