DE1214309B - Procedure for maintaining the charge of alkaline batteries - Google Patents

Description

Method of maintaining the charge of alkaline batteries The invention relates to a method for maintaining the charge of alkaline batteries, in particular of nickel-iron accumulators, in parallel switching operation with periodic interruption the charge, and a device for carrying it out.

Previously it was common practice to use alkaline batteries in emergency power systems used or only charged for the delivery of current peaks, by a small Charging current to charge continuously, which is just enough to handle the low occasional Compensate for consumption and self-discharge of the batteries.

Practice has shown that under certain conditions batteries, that were continuously charged according to this known charging method, not always the have desired optimal capacity.

The task is therefore to develop a charging process, compensated by the self-discharge losses and thereby the capacity of the accumulators is held at the setpoint.

According to the invention, this object is achieved in that the accumulators Purely time-dependent, after a long break, briefly with the full nominal charging current be charged, the charging time being chosen so that the average self-discharge of the accumulator is being balanced and the selected ratio between pause and charging time is constant.

In the event that the batteries, for example, in the event of a power failure once more heavily loaded is according to the method according to the present invention a one-time full charge with the full nominal charge current is provided. These Full charging is then automatically included in the schedule of the short charges described above switched on.

Preferably, each of the periodically carried out short charges lasts a few minutes, while the intermediate times are, for example, 12 hours. However Experiments have shown that these times, i.e. the duration of the current pulses and the Power breaks can also be chosen to be much shorter. To carry out the procedure For example, a contactless transistor circuit can be used as a timer will.

For example, a 100 Ah battery will self-discharge 3%. If this battery is now e.g. B. 12 hours, then she loses 3 in this time Ah in capacity. According to the invention, this amount of current of 3 Ah is restored in a short time loaded into the battery. Should this recharge with the nominal current of the battery, which is 20 A, results in a recharge time of 9 minutes. Under additional consideration of a load factor of 1.4 is the reloading time so about 12 minutes.

Since batteries of different capacities also have different self-discharges own, .is - the time ratio between idle time and reload time of the type depends on the battery.

To carry out the inventive method. driving, the switching arrangement shown in the drawing is preferably used. This consists essentially of an electric motor 1 fed by the alternating current network, with which a program disk 2 is rigidly connected and a second program disk 3 is connected to rotate only when a preferably electromagnetically actuated clutch 4 is switched on. The disk 2 controls the regular short impulse charges, while the disk 3 is only driven for a limited time via the clutch 4 by the motor after a power failure, when the battery has to cover the electricity requirement. Within this period of time, the batteries are recharged by a full charge.

In the drawing, the switching device is timed in the individual successive phases. To facilitate the overlooks the current-carrying connections were marked by wider lines.

The terminals 5 provide the tap for controlling the charging process The mains voltage to drive the motor 1 is applied to terminals 6.

F i g. 1 shows the circuit when the power is restored immediately after a power failure. When the battery is charged via the terminals 5 directly or via a relay, the motor 1 starts to run and the normally closed contacts 8 and 9 of the relay 7 are closed, so that firstly the control contacts 15 are bridged and secondly the magnetic coupling 4 carries current and the program disc 3 connects to the motor in rotation. The disk 3, which initially rested with the nose 12 on the stop pin 13, now rotates against the pull of the spring 11 in the direction of the arrow.

In Fig. 2 the rotation of the disk 3 has progressed so far that that the nose 12 has closed the contact 14. This gives the relay 7 power and pulls through, in such a way that the normally closed contacts 8 and 9 are only opened when the normally open contact 10 is already closed. The battery charge is now interrupted at contact 9. In addition, the magnetic coupling 4 is de-energized, see above that the disc 3 freely follows the train of the spring 11 and into the starting position returns. The relay 7 holds itself via contact 10.

From now on, the Kleinuren 5, as in FIG. 3 each time then bridged when the resilient contact 15 is closed by the nose 16 of the disk 2 will. So as long as the nose 16 brushes past the contact 15, the battery charged with the full charging current.

The time for one revolution of the motor axis or a corresponding one Gear axis can be 12 hours, for example, and is equal to the cycle time of the discs. This means that a charging current flows every 12 hours, the duration of which is preferred a few minutes.

Since the relay 7 receives its current directly from the network via its own normally open contact 10, the relay shown in FIG. 3 do not change the state of the circuit until the mains voltage fails. The relay 7 then drops out, and when the mains voltage returns, charging begins again as shown in FIG.

If necessary, the charging process can also be carried out manually by opening the Key contact 16 are initiated. It may be advantageous to use the key contact 16 to be designed so that it is opened by a relay as soon as the battery terminal voltage falls below a specified value.

With the circuit arrangement described, the inventive Perform procedures properly. Your practical testing has shown that with it a charge retention is possible without any loss of capacity of the accumulators is.

Claims (6)

Claims: 1. Method for maintaining the charge more alkaline Accumulators, in particular from nickel = iron accumulators, in parallel switching operation with periodic interruption of the charge, characterized in that the accumulators Purely time-dependent, after a long break, briefly with the full nominal charging current be charged, the charging time being chosen so that the average self-discharge of the accumulator is being balanced and the selected ratio between pause and charging time is constant. 2. The method according to claim 1, characterized in that that after a power failure the batteries are automatically fully charged carried out before the periodic recharges begin. 3. Procedure according to Claim 1, characterized in that by a voltage-dependent arrangement automatically a normal full charge is inserted as soon as the battery terminal voltage falls below a certain value. 4. Device for carrying out the process according to one or more of claims 1 to 3, characterized in that a is provided by the alternating current network fed electric motor (1), the one directly drives the program disc (2) controlling the short pulse charges and with a second program disc (3) to control the full charge is only connected to running when a clutch (4) is engaged. 5. Apparatus according to claim 4, characterized in that a spring (11) is provided which acts on the program disc (3) so that when the clutch (4) is released, the disc (3) with the nose (12) against the Stop pin (13) moves. 6. Apparatus according to claim 5, characterized in that a Relay (7) is provided, through whose break contact (8) the magnetic coupling current receives, while the charging current for the battery charge via the normally closed contact (9) flows and the normally open contact (10) is switched as a self-holding contact of the relay (7) is. Documents considered: German Patent No. 413 555; British U.S. Patent No. 908156; U.S. Patent No. 2,503,179; Elektronik, 7/1957, p. 220.