JPS6380728A - Charger - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a charging device for constant current charging.

(Prior Art) A charging device for constant current charging performs charging with a constant charging current, and is also used as a charging device for a vehicle battery.

Fig. 2 is a circuit diagram of a conventional charging device of this type, in which three-phase AC from a power source 1 is rectified by a rectifier circuit 2, and a single-phase AC is passed through a conversion circuit 3 that converts AC using PWM (pulse width modulation). After the voltage is converted to a predetermined voltage, a transformer 4 transforms the voltage into a predetermined voltage. Thereafter, the hatch leaf is charged by the direct current obtained by rectification by the rectifier circuit 5. The current value of the charging current that charges the hatch lift is detected by the current detector 6, and the value is fed back to the current control circuit 8, which controls the charging current so that it always flows at a constant current value. . The constant current control circuit 8 is composed of a well-known constant current circuit using transistors and operational amplifiers.

The current value of the charging current varies depending on the rated capacity of the battery, so a charging device that outputs a large current is used to charge a battery with a large rated capacity, and a charging device that outputs a small current is used to charge a battery with a small rated capacity. is usually used. However, in the past, if the rated capacities were the same, even if they were slightly different (for example, 390Ah and 312Ab), they were charged using the same charging device and with the same charging current.

However, when charging a relatively small capacity battery, this will result in a charging current larger than the appropriate value, which may cause the temperature of the electrolyte to rise and deteriorate the electrode plates, which may adversely affect the life of the battery. There was. In addition, when an excessive charging current is passed, the water content decreases significantly due to the generation of hydrogen when the inversion point is exceeded, and therefore there is a problem in that water must be replenished frequently.

(Objective and Structure of the Invention) The present invention has been made in view of the above points, and an object thereof is to reduce the frequency of water replenishment for constant current charging and to enable charging without adversely affecting battery life. In order to achieve this purpose, in a charging device for constant current charging, there is a selection means for selecting the rated capacity of the battery to be charged, and a charging current value is set to a constant value according to the rated capacity selected by the selection means. The configuration is such that a current control means is provided to control the current so that the current is maintained.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a circuit diagram of an embodiment of a charging device according to the present invention, in which the same components as in FIG. 2 are given the same reference numerals.

In the figure, reference numeral 9 consists of push button switches A and B, and a rated capacity selection switch serves as a selection means for selecting the rated capacity of the power battery to be charged. This is a current control circuit that controls the current value of charging current.

The charging device of this embodiment is for charging large batteries used as driving power sources for electric vehicles such as forklifts and golf carts, and has a rated capacity of 390Ah or 312A.
h batteries can be charged.

With the above configuration, if you want to charge a battery with a rated capacity of 390 Ah, press the push button switch A of the rated capacity selection switch. Then, the corresponding capacitance signal is input to the current control circuit 10, and the current control circuit 10 detects the charging current with the current detector 6 and controls the current value to be a constant current of 75 A, which is an appropriate value. . For example, if the charging current detected by the current detector 6 is smaller than 75 A, the current control circuit 10 increases the PWM pulse width of the AC conversion circuit 3 to increase the effective voltage on the primary side of the transformer 4. This increases the current value of the charging current. If the charging current is large, the opposite operation will occur. On the other hand, when the user wants to charge a battery with a rated capacity of 312 Ah, push button switch B is pressed. Then, the corresponding capacitance signal is input to the current control circuit 10, and this time the current value of the charging current is 50.
The PWM pulse width of the AC converter circuit 3 is set so as to provide a constant current of A. The current control circuit 10 feeds back the charging current detected by the current detector 6 in the same way as described above, and performs control to maintain the current value at 5OA.

According to the present invention, even if batteries have different rated capacities, they are charged with charging currents that are appropriate for each battery, so even if the reversal point is exceeded, moisture will not be excessively reduced. There is no need to refill the water frequently. Furthermore, since a charging current that is excessive compared to the rated capacity of the battery does not flow, the temperature of the electrolytic solution does not rise and the life of the battery is not shortened.

(Effects of the Invention) As explained above, in the present invention, in a charging device for constant current charging, a selection means for selecting a rated capacity of a battery to be charged, and a selection means for selecting a rated capacity of a battery to be charged, and a Since the present invention is configured to include a current control means for controlling the current value of the charging current to a constant value,
Reduce the frequency of water replenishment in charging equipment for constant current charging,
Moreover, it is possible to obtain the effect that the battery can be charged without shortening its life.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of a charging device according to the present invention, and FIG. 2 is a circuit diagram of a conventional charging device. l...power supply, 2.5...rectifier circuit, 3...AC conversion circuit, 4...transformer, 6...-current detector, 7...
・Battery, 9... Rated capacity selection switch, lO...
・Current control circuit

Claims (1)

[Claims] selection means for selecting the rated capacity of the battery to be charged;
A charging device for constant current charging, comprising current control means for controlling the current value of the charging current to a constant value in accordance with the rated capacity selected by the selection means.