JP2508309B2 - Battery charge control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a battery charge control device, and particularly to a proper charge when a solar cell used for artificial hygiene or the like is repeatedly charged and discharged to a load. The present invention relates to a battery charge control device for.

[Conventional technology]

Generally, the battery charge mode is a constant current charge full charge mode that charges from about 80% of the amount to be charged from the state immediately after the first discharge, and the charge amount decreases as the next step. There is a taper charging mode in which the battery is charged to the final capacity value while performing the charging, and a trickle charging mode in which a small charging stream is used to supplement self-discharge after this. Further, as a charging control method in the above-mentioned taper charging mode, there is a constant voltage electric method that detects the overcharged constant voltage level of the battery and continuously reduces the constant charging rate.

Conventionally, as shown in the block diagram of FIG. 4, a battery charging control device that realizes such a constant current voltage system includes a power source 11, a charging unit 14 that controls a charging flow, a battery 3 to be charged, and a battery charging. It is composed of a voltage sensor 5 for detecting various pressures, a load 10 represented by a communication device, etc., a discharging diode 9 forming a discharge path from the battery 3 to the load 10, and a current sensor 4 for detecting a charging current. . Now, a conventional example will be described with reference to the characteristics of general battery charging pressure, charging flow and charge amount shown in the explanatory views of FIGS. 2 (a), (b) and (c). The battery 3 is charged with electric power supplied from the power source 1 at a constant current controlled by the charging unit 14 which operates by receiving a signal corresponding to the detection voltage of the voltage sensor 5. This area corresponds to A of the full charge area in FIG. 2 (b). When the charging progresses and the battery voltage reaches a predetermined constant voltage (E in FIG. 2 (a)), the taper charging signal 6 is output from the voltage sensor 5 to the charging unit 14, and the taper charging signal 6 is output.
In the taper charging region of (b), the charging flow of the battery 3 is continuously reduced while the charging voltage of the battery 3 is kept constant, as shown in B of FIG. 2 (b). In the conventional example, the reduced current at the end of charging may vary depending on the set level of overcharge pressure.

[Problems to be Solved by the Invention]

The above-described conventional battery charge control device has a drawback that it is not easy to optimize the charge amount by the initial setting of the overcharge pressure, because the battery charge pressure characteristic changes over time and the battery temperature changes. That is, there is a risk of insufficient charging or overcharging.

An object of the present invention is to overcome the variation in the charging flow in the taper charging region, maintain an appropriate charging state without excess or deficiency of charging, and minimize the charging pressure stress. To provide.

[Means for solving the problem]

The battery charge control device of the present invention obtains a recharge rate which is a ratio of an integrated charge amount and an integrated discharge amount by means of detection means for detecting a battery charge current and a discharge current, and the recharge rate. When the value of reaches a predetermined threshold value, a calculation determining means that outputs a charging completion signal, and a charging current that switches the charging mode from the taper charging mode to the trickle charging mode each time the charging completion signal is input. Current control means and constant voltage level control means for changing the constant voltage level from the rate of increase in the amount of charge in the taper charging mode to the charging current required to secure the predetermined recharge rate in the remaining charging time. Have and.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 3 is a block diagram showing the configuration of the recharge current counter 7 of FIG. In this embodiment, the recharge rate data 12 output from the recharge rate counter 7 is received, and a signal 13 for controlling the taper charging pressure is output to operate so as to ensure the required recharge rate. It has a voltage level control unit 1 and a charging unit 2 that operates under the control of the recharge rate counter 7. The other configuration is the same as the conventional example. In FIG. 3, a recharge rate counter 7 includes an integrator 15 for digitally counting the integrated value of the charge amount and the discharge amount, a memory 16 for storing the count value, and a ratio of the integrated charge amount and the integrated discharge. It has a calculation judgment device 17 that performs a calculation and compares it with a predetermined value to judge it, and a charging completion signal generator 18 that outputs a charging completion signal that operates according to the signal of the judgment device. now,
The amount obtained by integrating the current value of the current sensor 4 and the time, that is, the total amount of charge so far is determined by the discharging diode 9 before the charging.
1 to 1.3 of the discharge amount discharged to the load 10 via
When the number of times is doubled, it means that the recharging rate counter 7 outputs the charging completion signal 8 because the charging completion state is reached, and the trickle charging mode is set. This mode shows the transition from C to D in FIG. 2 (b), and there is no danger of overcharging because the charging is such that the charge flow rate is sufficient to compensate for the self-discharge of the battery. Further supplementally, the recharge rate counter 7 counts the value and the time corresponding to the discharge flow of the power supply sensor 4 when the charging is switched to the discharging, and the accumulated discharging amount from the discharging to the charging is calculated. I remember. This discharge amount is compared with the discharge amount integrated value of the next charge, and the recharge rate for each cycle of discharge and charge, that is, the ratio of the charge amount to the above-mentioned discharge amount, is set to a numerical value in advance. ~ 1.3
Has a function of outputting a charge completion signal. If it is predicted from the rate of increase in the amount of charge in the taper charge mode that the recharge rate does not reach the set value within the remaining charge time, the level of the constant voltage charge pressure (E in FIG. 2 (a)) is lowered. The recharging rate is secured by raising the temperature to the charging double-flow characteristic of C in FIG. 2B, and the torquele charging double-flow level of D is obtained by the trickle charging mode. By such an operation, the battery charge state is properly maintained. In addition, at the lower level, where the charging has progressed for a while, the rate of increase in the amount of charge is checked, and when it is determined that the sufficient recharging rate can be secured for the remaining charging time, the level is lowered to E again ( (Dashed line) The operation is performed automatically so as not to apply charging pressure stress as much as possible.

〔The invention's effect〕

As described above, the present invention compares the previous accumulated discharge amount with the next accumulated discharge amount, and is provided with the recharge rate counter and the constant voltage level control unit for determining the excess or deficiency of charging, so that it is appropriate. This has the effect of accurately maintaining the state of charge. In addition, the constant voltage charging voltage level setting is not required to be strict, and the minimum charging voltage stress and it is not applied from the minimum time, so a battery charging control device capable of holding the battery life longer can be provided. There is also an effect that can be provided.

[Brief description of drawings]

FIG. 1 is an embodiment and block diagram of the present invention, FIG. 2 is a general explanatory view showing charging characteristics of a battery, FIG. 3 is a block diagram of a recharging flow rate counter of the present embodiment, and FIG. The figure is a block diagram of a conventional battery charge control device. 1 ... Constant voltage level control unit, 2, 14 ... Charging unit, 3 ... Battery, 4 ... Current sensor, 5 ... Voltage sensor, 6 ...
Taper charge signal, 7 ... Recharge rate counter, 8 ... Charge completion signal, 9 ... Discharge diode, 10 ... Load, 11 ...
… Power supply, 13 …… Taper charging pressure control signal, 15 …… Integrator, 16 …… Memory, 17 …… Calculation judge, 18 …… Charging completion signal generator.

Claims (2)

(57) [Claims] 1. A detection means for detecting a battery charging current and a discharging current, and a recharging rate, which is a ratio of an integrated charging amount and an integrating discharging amount, is obtained from the charging current and the discharging current, and the value of the recharging ratio is preset. Calculation determining means for outputting a charge completion signal when the predetermined threshold value is reached, and current control means for charging current for switching the charge mode from the taper charge mode to the trickle charge mode each time the charge completion signal is input. A constant voltage level control means for changing the constant voltage level in order to obtain a charging current required to secure a predetermined recharge rate from the rate of increase in the amount of charge in the taper charge mode to the remaining charge time. A battery charge control device characterized by: 2. The calculation determining means digitally counts an integrated charge amount and a discharge amount from a charge current and a discharge current of the detection means, a memory for storing count information of the integrator, and information of the memory. Calculate the recharge rate from
An operation determination unit that determines that the value of the recharge rate has reached a threshold value indicating the completion of a predetermined full charge, and a charge completion generator that outputs a charge completion signal according to the determination signal of the operation determination unit. The battery charge control device according to claim 1, further comprising: