JPS5828181A - Charging system for sealed nickel-cadmium storage battery - Google Patents

Abstract

PURPOSE:To realize an ideal completely charged state of a sealed nickel-cadmium storage battery by charging the battery with a constant current, giving the differential value between the charging voltage and the charging time by actuating a detecting circuit, and stopping the charging according to the said differential value. CONSTITUTION:A Ni-Cd storage battery 1 is connected to a rectifier 2 through a switch 3. A series circuit consisting of a timer 4 and a detecting circuit 5 is connected parallel to the battery 1. The switching-off control of a switch 3 is carried out by giving the output of the circuit to a control circuit 6. When the battery 1 is charged with a constant current up to above 10% its capacity, the circuit 5 is actuated by a timer 4 so as to give the differential value (dV/dt) between the charging voltage (V) and the charging time(t). After that, at the point when the above differential value becomes under zero, the charging is stopped by turning off the switch 3. Consequently, an ideal complete charging can be carried out by preventing overcharge irrespective of such conditions as environmental temperature and the charging current.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a charging method for photoelectrically charging a closed type nickel-cadmium storage battery (hereinafter referred to as Ni-Cd storage battery).

Conventionally, 17'Ni-Cd storage batteries a have been photoelectrically charged using several charging methods described below.

(1) Charging method using a current less than “sao”.

According to Koku, the storage battery will not be damaged by excessive photoelectricity!
However, it does have the disadvantage that it takes a long time to charge.

(2) General 111-0 (I storage battery has a charging curve as shown in Figure 1. In this case, 100 times are charged at point B, but the voltage becomes steep before that point. There is a method that detects this at five points and issues a charging completion detection signal. However, with this method, the battery voltage fluctuates by l1fK, so compensation is required. equipment is required, and charging cannot be easily controlled.

(3) Also, as can be understood from Figure 1, gas generation begins shortly before full charging, so there is a method of detecting the time when the internal pressure of the storage battery rises to a predetermined value as the completion of charging. However, in order to set K so that the internal pressure of the L storage battery can be detected, 1 is required.
Unless each storage battery is specially processed to enable internal pressure detection, the temperature will rise. Therefore, there is a method of detecting the end of charging when the temperature reaches a constant value or when the difference between the device and the outside temperature stops at a constant value. In this case, a large error may occur in the temperature measurement situation.

The above-mentioned photoelectric method σ is implemented either alone or in combination with a timer, etc., but in each case, the quality history of the set value is determined by the control conditions f such as photoelectric xi and outside air Wlf. It is difficult to obtain an ideal state of charge, as the state of charge may be set too low, or the battery may tend to be overcharged.

This invention was made based on the above IM circumstances.N
1-Cja storage battery has a maximum value at the beginning of charging depending on its history, charging current value, outside temperature f, etc., but after that the voltage increases rapidly, reaches the maximum fiI at full charge, and gradually decreases after a while. Focusing on the point where the current curve is drawn, we can detect the ideal complete charging time that does not suffer from f¥ under one condition from the relationship between the storage battery voltage jump during charging and the charging time (1).
However, attempts are made to provide a charging method that allows uFIy.

Hereinafter, this invention will be specifically explained with reference to wyi2sw and a+ev. In Figure 2, N1-cd storage W
%L is connected in series to the secondary side terminal of the p1 rectifier 2 via a switch 3. Further, a timer 4 and a detection circuit 5 are connected in parallel with the rectifier 2 between both terminals of the Ni-0d storage battery. A control circuit 6 is provided which controls the switch 3 to be turned off using a signal from the detection circuit 5.

With this configuration, when the stile is first turned on, the timer 4 is activated to start charging the battery at a constant rate. When the timer 4 is turned on after a certain period of time has elapsed, the detection circuit 5 is closed to the storage battery IK. In the detection circuit 5, the charging voltage (V) and the charging time (rxm) are determined, and the differential value "/'at is determined. As can be understood from Fig. 311, the renal total likelihood voltage 1 is dV
There is a relationship of /a, > 6.

Fully charged Rdv/dt=0-+)[Ridka')t'
s dv/dt<O. This relationship is constant regardless of the % environmental temperature f1 source voltage 11rN, etc. Therefore, at detection time j85, when dv/dt<00, this is detected and wA-
A detection signal is applied to the circuit 6 to turn off the switch 3.

Of course, at this time, even if the current value is continuously photovoltaic, it will not cause damage to the storage battery. tff, that is, it may be controlled to a safe current.

In this invention, the reason why the timer 47 is operated for a certain period of time and the five detection circuits and the storage battery 1 or C are cut off is as follows. That is, in a storage battery that has been stored for a long time, σ may have a maximum value such as 0 point at the beginning of the charge amount, as shown in FIG. Of course, after this 1
1c ij dv/at<O, so if the detection circuit 5 is active at this time, it will cause a malfunction. There is a slight difference in the time of year when the first maximum value of Kono f1 occurs depending on the battery history, light Wtt flow, outside temperature, etc.

As a result of testing storage batteries that have been stored for more than 5 to 6 months under rough conditions, when charging with '/10' or IC current, the above first maximum value is 1.
Within 0 hours of charging, ie /'t'.

It has been confirmed that v appears within 1 hour with the m waterfall of C and within 6 minutes with the IC current, and that the effect disappears and /dt > 0. Therefore, the storage battery capacity is 10-
After the above charging is completed, if the timer 4 is set so that the detection circuit 5 is activated, the malfunction can be completely eliminated.

As described in detail above, this invention applies constant current photoelectric charge to VC, N1-C (1 storage battery), and after the charge of 10q6 or more of storage battery S* reaches -1, the detection circuit is activated as a storage battery voltage jump during charging. When a relationship of dv/dt<00 is detected between the photoelectric current and the photoelectric current! Since the current is stopped or controlled to a small safe current, there is no malfunction, and even under any conditions, there is no need to change the control 1mr, and charging can be completed at the ideal time. An excellent effect can be achieved in that there is no risk of overcharging.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the parameters of photovoltage and photovoltaic time of Ni-G (1 storage battery). This is a chart showing special parameters of photovoltaic voltage and charging time. 1...Ni-Cd storage battery 2...II current device 3...
Switch 4 - Timer 5... Detection circuit 6... Control circuit patent applicant Hideaki Sato, patent attorney for Furukawa Battery Co., Ltd.

Claims (1)

[Claims] Detection after the closed type nickel cadmium storage F battery is charged at a constant flow rate and charged to 10 times or more of the storage battery capacity (b)
The storage battery voltage during charging and the charging time (11r)
), when the relationship of dv/dt<0 is detected, the light t%
Current V and lukewarm or small safety current K11llill
This is a patented charging method for sealed nickel-cadmium storage batteries.