JPH04197043A - Charger - Google Patents

Abstract

PURPOSE:To reduce a charging time in response to aging of a battery to an increase in the number of charging/discharging times and a reduction in its capacity by controlling the operating time of a timer circuit in response to the charging times received from a charging time controller. CONSTITUTION:A charger reads the charging times of a battery by a charging time memory 108 by a charging time controller 106 before charging is started from a waiting state, and sets a charting time in a timer 104 by a timer controller 105. Then, a switch 103 is closed by the timer 104, and charging is started. Thus, a charging time is controlled in response to the charging times of the battery thereby to realize a charging state responsive to the actual capacity of the battery.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a charging device for charging a secondary battery for use in electronic equipment and the like.

Conventional technology Non-rechargeable primary batteries, such as manganese dry batteries, have traditionally been used as power sources for electronic equipment such as portable radios, televisions and mobile radios, and in recent years, nickel-cadmium batteries and storage batteries for small ships have been used. Rechargeable batteries, which can be recharged and used over and over again, have come into widespread use. In addition, the biggest feature of secondary batteries is that even if the battery is used up, it can be reused 300 to 500 times by charging it. You are required to increase the number of times you can do it.

The first conventional charging device will be described below with reference to the drawings. FIG. 5 is a block diagram of the first conventional example, and FIG. 6 is a flowchart showing its operation state transition.

A power supply circuit 501 that supplies power to the charging device has a current control circuit 502 that controls the charging current, and a current control circuit 502 that controls the charging current.
Power is supplied to the secondary battery 505 for charging through the switch 503, and the timer circuit 504 controls the charging time through the switch 503.

The operation of the charging device configured as described above will be explained next. From a standby state 601, the charging device turns on the switch 503 and starts charging (state 602). Charging continues until the timer circuit 504 reaches a preset time (states 603 and 604). When the timer circuit 504 reaches a preset time, the switch 503 turns OFF and charging ends (state 605).
).

Next, a second conventional charging device will be explained with reference to the drawings. FIG. 7 is a schematic diagram of the second conventional example, and FIG. 8 is a flowchart showing the operation state transition thereof.

A power supply circuit 701 that supplies power to the charging device includes a current control circuit 702 that controls the charging current, and a current control circuit 702 that controls the charging current.
The switch 703 and the current control circuit 702 are controlled by a terminal voltage detection circuit 704 that detects the terminal voltage of the battery.

The operation of the charging device configured as described above will be explained next. From the standby state 801, the charging device turns on the switch 703 and starts charging (state 802). While charging,
The terminal voltage detection circuit 704 monitors the terminal voltage of the rechargeable battery, and the current control circuit 702 controls the charging current based on the value. Charging is now continued until the detection terminal of the terminal voltage detection circuit 704 reaches the preset upper limit terminal voltage (states 803 and 804). When the detection terminal of the terminal voltage detection circuit 704 reaches a preset upper limit terminal voltage (that is, the terminal voltage of the battery 705), the switch 703 is turned OFF and charging ends (state 805).
).

Problems to be Solved by the Invention However, in the first conventional example of the charging device operating in the conventional manner, the charging time is always constant, and after the secondary battery is charged and discharged many times, the battery ages and the capacity decreases. When the amount decreases, overcharging occurs and the battery life is further shortened.

In addition, in the second conventional example, the relationship between the terminal voltage and the terminal current is always constant, and the maximum current value that can flow through the secondary battery during charging (hereinafter referred to as maximum charging current) is determined by the capacity, so if the capacity decreases. When this happens, the charging current becomes relatively excessive, which again has the problem of further shortening the life of the battery.

An object of the present invention is to provide a charging device that solves the above-mentioned conventional problems and extends the life of a battery.

Means for Solving the Problems In order to achieve the above object, the present invention has a first aspect of the invention.
A power supply circuit that supplies power to the charging device, a current control circuit that controls charging current, a timer circuit that controls charging time by its operation, a charging number storage circuit that stores the number of charging times, and the charging number storage circuit. Read out the number of charging times,
It also includes a charging number control circuit that stores the number of charging times in the charging number storage circuit each time charging is performed, and a timer control circuit that controls the operating time of the timer circuit according to the number of charging times received from the charging number control circuit. It is configured to have

Further, the second invention includes a power supply circuit that supplies power to the charging device, a current control circuit that controls the charging current, a terminal voltage detection circuit that detects the terminal voltage of the secondary battery to be charged, and a memory that stores the number of charging times. a charging frequency storage circuit that reads the charging frequency from the charging frequency storage circuit and stores the charging frequency in the charging frequency storage circuit each time charging is performed; and a charging frequency control circuit that reads the charging frequency from the charging frequency storage circuit and stores the charging frequency in the charging frequency storage circuit each time charging is performed; setting a maximum charging current in the current control circuit according to;
The present invention also includes a current value setting circuit that detects through the terminal voltage detection circuit that a predetermined voltage value has been reached and controls the current control circuit to cut off the output.

Effects of the present invention With the above-described configuration, the first invention can control the charging time to be reduced in response to an increase in the number of charging and discharging. control to reduce charging time.゛In addition, in the second invention, the maximum charging current value is controlled to decrease according to the number of times the battery is charged, and charging is terminated when a predetermined voltage value is reached, so that the maximum charging current value is controlled to decrease according to the actual capacity of the battery. Achieves a stable charging state.

Embodiments Hereinafter, embodiments of the first invention will be described with reference to the drawings.

FIG. 1 is a diagram of a charging device according to an embodiment of the present invention;
FIG. 2 is a flowchart similarly showing the operation state transition.

In FIG. 1, a secondary battery 107 for charging and a charging number storage circuit 108 that stores the number of charging times using an electrically erasable/writable memory (hereinafter referred to as EEFROM) are housed in the same casing 109. There is. The power given from the power supply circuit 101 that supplies power to the charging device is sent to the current control circuit 102 that controls the charging current, and the charging current is set to 0N10FF.
A secondary battery 107 for charging via a switch 103 that
is given to.

Reads the value of the number of charges from the number of charges memory circuit 108,
Alternatively, the charging number control circuit 106 to write provides the value of the number of charging times to the timer control circuit 105, and the timer control circuit 1
05 is a timer circuit 10 according to the read number of charging times.
4, and the timer circuit 104 controls the switch 103.

The operation of the charging device configured as described above will be described below.

In the charging device, before starting charging from the standby state 201, the number of times the battery has been charged is read out from the number of charging times storage circuit 108 by the number of charging times control circuit 106, and the number of times the battery has been charged is read out from the number of times storage circuit 108,
5, the charging time is set in the timer circuit 104 (state 202). Then, the timer circuit 104 turns on the switch 103 and starts charging (state 2).
03).

Charging continues until the timer circuit reaches the preset time (states 204, 205).

When the timer circuit 104 reaches a preset time (state 204), the charging number control circuit 106, which has learned of the expiration of the time from the timer circuit 104 through the timer control circuit 105, increments the charging number value by 1 and stores it in the charging number storage circuit. 108 (state 206), the timer circuit 104 turns off the switch 103, and charging ends (state 207).

As described above, according to this embodiment, by controlling the charging time according to the number of times the battery is charged, it is possible to realize a state of charge that corresponds to the actual capacity of the battery. The lifespan of the battery is longer and more economical compared to when it is used.

Next, an embodiment of the second invention will be described with reference to the drawings. FIG. 3 is a block diagram of a charging device according to an embodiment of the present invention, and FIG. 4 is a flowchart showing its operating state transition.

In FIG. 3, a secondary battery 307 for charging and a charging number storage circuit 308 that stores the number of charging using an electrically erasable/writable memory (hereinafter referred to as EEPROM) are housed in the same casing 309. There is. The power given from the power supply circuit 301 that supplies power to the charging device is sent to the current control circuit 302 that controls the charging current, and the charging current is turned ON10F.
Secondary battery 3 for charging via F switch 303
It is given in 07.

Reads the value of the number of charges from the number of charges storage circuit 308,
Alternatively, the charging number control circuit 306 to write provides the value of the number of charging times to the current value setting circuit 304, and the current value setting circuit 304
sets the maximum charging current value in the current control circuit 302 according to the given number of charging times, and the current control circuit 302 controls the charging current to the secondary battery 307 accordingly. Further, the current control circuit 302 is set to turn off the switch 303 when the terminal voltage of the secondary battery 307 detected by the terminal voltage detection circuit 305 exceeds a predetermined value.

The operation of the charging device configured as described above will be described below.

When the charging device is in a standby state 401, before starting charging, the number of times the battery has been charged is read out from the number of charging times storage circuit 308 by the number of charging times control circuit 306, and the value is given to the current value setting circuit 304. sets the maximum charging current value in the current control circuit 302 according to the given number of charging times (state 402). The switch 303 is turned on by the current value setting circuit 304, and the current control circuit 302 starts charging while controlling the charging current to the secondary battery 307 according to the set maximum charging current value (state 403).

The terminal voltage detection circuit monitors the terminal voltage of the secondary battery 307, and charging is continued until the preset voltage is reached (states 404 and 405).

When the terminal voltage of the secondary battery 307 reaches a preset voltage (state 404), the terminal voltage detection circuit notifies the charging frequency control circuit 306 via the current value setting circuit 304 or directly, and the charging frequency control circuit 306 The charging number value is incremented by 1 and written in the charging number storage circuit 308 (state 406), while the current value setting circuit 304 turns off the switch 303 and charging ends (state 40).
7).

As described above, according to this embodiment, by controlling the maximum charging current value according to the number of times the battery is charged, it is possible to realize a charging state according to the actual capacity of the battery.
The battery life is longer and more economical than when using conventional charging circuits.

Note that among the components of the above embodiment, the secondary battery 108,
308, the portions other than the charging number storage circuits 108, 308 and the power supply circuits 101, 301 may be realized by software.

In addition, in the above embodiment, the charging number memory circuit 108°308
Although an EEPROM is used as an example, it is also possible to use a FROM that allows only additional writing or a static RAM backed up by a battery.

Also, if you change the battery to be charged, the battery 107°307
By housing the battery and the number of charge storage circuits 108 and 308 in the same housing, each battery can be charged under optimal charging conditions.

Further, the switches 103, 303 may be electronic switches, and instead of turning off the switch, the current control circuit 103
, 302 may be controlled by making it infinitely small.

Furthermore, by changing the contents of the EEPROM externally, it is possible to realize arbitrary charging conditions.

Furthermore, it is also possible to control the timer circuit from the outside and set the charging time (or charging current) to correspond to various types of batteries.

Effects of the Invention As described above, the first invention provides a function to control the charging time according to the number of charging cycles, so that even if the battery capacity decreases due to the increased number of charging/discharging cycles, charging can be performed accordingly. In addition, the second invention controls the maximum charging current value to be reduced according to the number of times the battery is charged, and stops charging when a predetermined voltage value is reached, thereby increasing the actual battery charge. The present invention provides a practically effective charging device that has the great effect of realizing a charging state according to the capacity and allowing charging without shortening the life of the battery.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a charging device according to a first embodiment of the present invention, FIG. 2 is a flowchart showing its operating state transition, and FIG. 3 is a block diagram of a charging device according to a second embodiment of the present invention. 4 is a flowchart showing the operating state transition, FIG. 5 is a block diagram of the first conventional charging device, FIG. 6 is a flowchart showing the operating state transition, and FIG. 7 is a flowchart showing the second conventional charging device. FIG. 8 is a block diagram of the conventional charging device, and a flowchart showing the transition of its operating state. 101.301...Power supply circuit, 102,302
...Current control circuit, Log, 303...
・Switch, 104... Timer circuit, 105
...Timer control circuit, 106,306...
... Charging number control circuit, 107,307...
Charging number memory circuit, 304... Current value setting circuit, 305... Terminal voltage detection circuit. Name of agent: Patent attorney Haruaki Koebi and 2 others @3 Figure 5 Figure 6 Figure 70 Figure 8

Claims (3)

[Claims] (1) A power supply circuit that supplies power to the charging device, a current control circuit that controls charging current, a timer circuit that controls charging time through its operation, a charging number storage circuit that stores the number of charging times, and the number of charging times. a charging frequency control circuit that reads the charging frequency from a storage circuit and stores the charging frequency in the charging frequency storage circuit each time charging is performed; and an operating time of the timer circuit according to the charging frequency received from the charging frequency control circuit. A charging device having a timer control circuit that controls. (2) A power supply circuit that supplies power to the charging device, a current control circuit that controls the charging current, a terminal voltage detection circuit that detects the terminal voltage of the secondary battery to be charged, and a charging number memory that stores the number of charging times. a charging frequency control circuit that reads the charging frequency from the charging frequency storage circuit and stores the charging frequency in the charging frequency storage circuit each time charging is performed; a current value setting circuit that sets a maximum charging current in the current control circuit, and controls the output of the current control circuit to be cut off when it detects that the voltage exceeds a predetermined voltage value through the terminal voltage detection circuit; A charging device with (3) The charging device according to claim 1 or 2, wherein the charging number memory circuit is housed in the same casing as the rechargeable secondary battery.