JPH10248178A - Charging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging apparatus by which the charging depth of a module battery is made deep and by which a charging operation can be performed in a boosting manner. SOLUTION: A high current is made to flow to module batteries 1, 2 via respective changeover switches 7, 8 from a charging power supply 9, the module batteries are charged, temperatures at this time are detected by temperature sensors 3, 4, and a temperature change rate is computed by a temperature- change-rate computing circuit 5. The module batteries are charged by the high current until the temperature change rate becomes a value A. When the temperature change rate exceeds the value A, a low current or a pulse current is made to flow from the charging power supply 9, and the module batteries 1, 2 are charged. When the temperature change rate exceeds a value B, their charging operation is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a charging device,
In particular, it relates to a charging device for charging a nickel-metal hydride storage battery.

[0002]

2. Description of the Related Art Recently, in an electronic device or the like using a battery as a power source, a non-rechargeable battery such as a manganese dry battery is used.
Secondary batteries, such as nickel cadmium storage batteries, which can be repeatedly charged and used repeatedly, have been increasingly used. However, since the secondary battery has a lower energy density than the primary battery, a large battery is required to obtain the same battery capacity as the primary battery.

However, recently, a nickel-metal hydride storage battery capable of obtaining a much higher capacity than a nickel-cadmium storage battery has been developed and put into practical use. This nickel-metal hydride storage battery uses nickel for the positive electrode and a hydrogen storage alloy for the negative electrode, and has a feature that a battery capacity 50 to 100% higher than that of a conventional nickel-cadmium storage battery can be obtained.

[0004]

However, nickel-metal hydride storage batteries have a greater temperature rise during rapid charging than nickel-cadmium storage batteries, and it is difficult to detect full charge even when charging while monitoring temperature and voltage. There is. In addition, when charging a plurality of nickel-metal hydride batteries, there is a disadvantage that the variation among the batteries is large.

[0005] Therefore, a main object of the present invention is to provide a charging device capable of increasing the depth of charge of a battery.

[0006]

The invention according to claim 1 is
A charging device for charging a battery, comprising: detecting means for detecting a temperature change rate during charging of the battery; and a power supply for outputting power for charging the battery with high current, low current, and pulse current. Until a predetermined temperature change rate is detected by the detecting means, the battery is charged by supplying a high current from the power supply to the battery, and a low current or a pulse current is supplied from the power supply to the battery according to the detection of the predetermined temperature change rate. And control means for performing control for charging the battery.

According to the second aspect of the present invention, the control means of the first aspect stops charging in response to the detection of the predetermined second rate of change.

[0008] In the invention according to claim 3, the battery according to claim 1 is provided in plurality, the detecting means detects the temperature change rate of each battery, and the control means detects the first temperature change rate of each battery. The battery is charged by supplying a high current from the power supply to each battery until it detects that the temperature change rate has reached the first temperature change rate. A low current or a pulse current is supplied to the battery, and charging is stopped when the temperature change rate of the battery reaches a predetermined second temperature change rate.

In the invention according to claim 4, the battery according to any one of claims 1 to 3 is a nickel-metal hydride storage battery.

[0010]

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, module batteries 1,
2 is configured by combining a plurality of nickel-metal hydride storage batteries. Each module battery 1, 2 has a temperature sensor 3,
The temperature of the module batteries 1 and 2 at the time of charging is detected and supplied to the temperature change rate calculation circuit 5. The temperature change rate calculation circuit 5 calculates the temperature change rate of the module batteries 1 and 2 during charging. The CPU 6 switches the changeover switches 7 and 8 according to the temperature change rate. The changeover switches 7 and 8 switch between a high current and a low current or a pulse current supplied from the charging power supply 9 and supply the same to the module batteries 1 and 2.

FIG. 2 is a diagram showing a specific configuration of the charging power supply and the changeover switch shown in FIG. An AC voltage is supplied from an AC power supply 10 to a rectifier diode 11 and rectified. The rectified voltage is smoothed by a capacitor 12 to become a DC voltage, and the DC voltage is supplied to a switching power supply. The switching power supply includes a switching transformer 13, a rectifier diode 14, a smoothing capacitor 15, a photocoupler 16, a drive circuit 17, and a switching transistor 18.

The DC voltage output from the switching power supply is applied to first contacts of the changeover switches 7 and 8 via a diode 19 for flowing a large current to the module batteries 1 and 2, and a diode for flowing a low current. 20 and resistor 22
Are supplied to the second contacts of the changeover switches 7 and 8 via the switch, and a DC voltage is supplied to the emitter of the transistor 26 via the diode 21 in order to supply a pulse current. A pulse signal is input to the base of the transistor 26. This pulse signal is output when the comparator 25 compares the sawtooth wave output from the sawtooth wave generation circuit 23 with the reference voltage output from the reference voltage generation circuit 24. The pulse current output from the transistor 26 is supplied to the third contacts of the changeover switches 7 and 8.

FIG. 3 is a flowchart for explaining the operation of one embodiment of the present invention, and FIG. 4 is a diagram showing a battery temperature-charge time characteristic.

In the embodiment of the present invention, as shown in FIG. 4A, the temperature change rate during the charging of the module batteries 1 and 2 becomes dT / dt = A value (first predetermined value). Is charged with a high current, and when the temperature change rate reaches A, the battery is charged with a low current or a pulse current, and the temperature change rate is as shown in FIG.
When the B value (predetermined second value) is reached as shown in (1), charging is terminated, thereby increasing the depth of charge.

More specifically, the switching power supply of the charging power supply 9 generates a DC voltage, which is supplied to the changeover switches 7 and 8 via the diode 19 shown in FIG. Are charged with a high current. At this time, the temperature sensors 3 and 4 attached to the module batteries 1 and 2 detect the temperature of the module batteries 1 and 2 at the time of charging. Then, the temperature change rate calculation circuit 5 calculates the temperature change rate based on the detected temperature and supplies the calculated temperature change rate to the CPU 6.

The CPU 6 determines whether the temperature change rate of any one of the module batteries 1 and 2 has reached the value A shown in FIG. 4A, and if not, continues to monitor the temperature change rate. . Then, when the temperature change rate of any of the cells reaches the value A, the CPU 6 switches the charging mode. That is,
For example, if the temperature change rate of the cell of the module battery 1 has reached the value A, control is performed such that the contact of the changeover switch 7 is switched to charge the module battery 1 with a low current or a pulse current.

The CPU 6 measures the temperature change rate again and determines whether or not the temperature change rate of any of the cells of the battery has reached the B value shown in FIG. 4B. If not, continue monitoring the temperature change rate. If there is a cell that has reached the B value, the cell is disconnected, charging of the cell is terminated, and charging is continued for a cell that has not reached the B value.

In the above-described embodiment, the case where two module batteries 1 and 2 are charged has been described. However, the present invention can be applied to a case where one battery is charged without being limited to this.

[0019]

As described above, according to the present invention, the rate of temperature change when charging a battery with a high current is detected, and when the rate of temperature change exceeds a predetermined value, the low rate is detected. By charging the battery with the current or the pulse current, the charge depth is increased and rapid charging becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a specific circuit diagram of the charging power supply shown in FIG.

FIG. 3 is a flowchart for explaining the operation of the embodiment of the present invention;

FIG. 4 is a diagram showing a battery temperature-charge time characteristic.

[Explanation of symbols]

 1, 2 module battery 3, 4 temperature sensor 5 temperature change rate calculation circuit 6 CPU 7, 8 changeover switch 9 charging power supply

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Sato 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Katsuhiko Niiyama 2-chome Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Keiji Kishimoto 2-5-5 Keihan Hondori, Moriguchi City, Osaka Pref. Sanyo Electric Co., Ltd. (72) Ikuo Yonezu 2 Keihanhondori, Moriguchi City, Osaka 5-5-5 Sanyo Electric Co., Ltd. (72) Inventor Koji Nishio 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (4)

[Claims] 1. A charging device for charging a battery, comprising: detecting means for detecting a temperature change rate during charging of the battery; and charging means for charging the battery with a high current, a low current, and a pulse current. A power source that outputs power, and until a predetermined temperature change rate is detected by the detection unit, a high current is supplied from the power source to the battery to charge the battery, and in response to detecting the predetermined temperature change rate. And a control means for performing control for flowing a low current or a pulse current from the power supply to the battery to charge the battery. 2. The charging apparatus according to claim 1, wherein said control means stops said charging in response to detection of a predetermined second rate of change by said detection means. 3. A plurality of said batteries are provided, wherein said detecting means detects a temperature change rate of each of said batteries, and said control means sets a first temperature change rate of each of said batteries determined in advance by said detecting means. The battery is charged by supplying a high current from the power supply to each battery until it is detected that the temperature change rate has reached the first temperature change rate. 2. The method according to claim 1, further comprising: supplying a low current or a pulse current to the battery, and stopping the charging when the temperature change rate of the battery reaches a predetermined second temperature change rate. apparatus. 4. The charging device according to claim 1, wherein the battery is a nickel-metal hydride storage battery.