JP2000116018A - Charger for charging a plurality of secondary batteries - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely reduce damage to a primary battery that is fitted by mistake with an extremely simple circuit. SOLUTION: A charger for charging a plurality of secondary batteries is provided with a fitting part for fitting a plurality of secondary batteries 1 detachably and simultaneously charges the secondary batteries 1 that are fitted to the fitting part. Further, in the charger, a voltage divider resistor 12 is connected in series with a plurality of secondary batteries 1, and the secondary batteries are connected in parallel one another and at the same time are connected to a power supply circuit 9 with output voltage-limiting characteristics for controlling an output voltage to a value that is lower than a set voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charger for removably mounting a plurality of secondary batteries for charging. In particular, the present invention relates to a charger that prevents adversely affecting a primary battery that is incorrectly installed.

[0002]

2. Description of the Related Art In some cases, a charger for charging a rechargeable battery of the type A1 to AAA is equipped with a primary battery which cannot be charged. This is because a secondary battery is commercially available with the exact same outer shape as a non-rechargeable single- to single-type primary battery. In a battery charger of a type in which a plurality of secondary batteries are mounted and charged all together, a primary battery that cannot be charged may be set together with the secondary battery. At this time, it is difficult to identify the primary battery,
It will be charged together with the secondary battery. Primary batteries are
It is a disposable battery and is not manufactured considering charging. Therefore, when the primary battery is charged, adverse effects such as liquid leakage occur. The electrolyte leaked from the battery corrodes the charger, causing poor contact of the contacts and failure of the charging circuit. For this reason, it is necessary for the charger to take measures to prevent adverse effects such as liquid leakage when the primary battery is incorrectly mounted.

[0003] Chargers for charging a plurality of batteries together include a type in which batteries are connected in series and a type in which batteries are connected in parallel to charge. A charger connected and connected in series charges all batteries at the same current, and a charger connected and connected in parallel charges all batteries at the same voltage.

[0004] A charger for connecting a plurality of batteries in series and charging them together can limit the charging current to a small amount and reduce the leakage of the primary battery. However, to achieve this, a constant current feedback circuit that controls the charging current is required. For this reason, the charging circuit is complicated and the manufacturing cost increases. Also, if the charging current is limited to a small value,
The charging time of the secondary battery becomes longer, and rapid charging cannot be performed in a short time.

A charger for connecting batteries in parallel and charging them is as follows:
The charging current of each battery does not become the same. For this reason, the battery can be charged in an ideal state by distinguishing the primary battery from the secondary battery and controlling the charging current of the primary battery while controlling the charging current to be small.

[0006]

However, a charger for connecting a plurality of rechargeable batteries in parallel and charging them together distinguishes whether the set battery is a primary battery or a rechargeable battery. Is difficult. Also, when the primary battery is identified,
A circuit for interrupting charging of the primary battery is also complicated.
This is because, in order not to charge the battery identified as the primary battery, switching elements are connected in series with all the batteries, and the switching elements are controlled by a circuit for distinguishing between the primary battery and the secondary battery. .

[0007] If it does not matter that the control circuit becomes complicated, the primary battery and the secondary battery can be determined from the difference in charging characteristics. This is because the primary battery and the secondary battery have different characteristics in which the voltage changes when charged. For example, nickel-cadmium batteries and nickel-hydrogen batteries which are secondary batteries have a maximum voltage of about 1.
Although the voltage is 5 V, a non-rechargeable alkaline battery or the like, which is a primary battery, has a higher battery voltage beyond 1.5 V when charged. Therefore, the primary battery and the secondary battery can be identified by detecting the battery voltage.

[0008]

However, in order to realize this, a circuit for detecting the voltage of the battery being connected in parallel and detecting the voltage of the battery being connected in parallel and changing each battery voltage is required. It is necessary to have a circuit configuration. If all the batteries are directly connected in parallel, there is no difference between all the battery voltages, and it becomes impossible to distinguish between the primary battery and the secondary battery. For this reason, it is necessary to connect a resistor in series with the battery and detect the voltage at both ends of each battery so that the voltage of each charged battery changes. For this reason, the circuit for discriminating between the primary battery and the secondary battery becomes considerably complicated.

[0009] Furthermore, the charger can reduce the charging current of the battery, thereby reducing the leakage of the erroneously set primary battery. However, the charger for realizing this is a complicated circuit similar to the circuit for determining the primary battery and interrupting the charging, and increases the manufacturing cost. This is because it is necessary to provide each battery with a constant current feedback circuit for controlling the charging current to be constant.

[0010] The present invention has been developed to solve such disadvantages. An important object of the present invention is to provide a charger for charging a plurality of secondary batteries, which can reduce the harm of a primary battery that is incorrectly mounted with an extremely simple circuit.

[0011]

The charger according to the present invention has a mounting portion 4 for detachably mounting a plurality of secondary batteries 1 and charges the secondary batteries 1 mounted on the mounting portion 4 simultaneously. . Further, the battery charger according to claim 1 of the present invention includes a plurality of secondary batteries 1.
And a voltage dividing constant resistance 12 in series. The secondary batteries 1 to which the voltage dividing constant resistance 12 is connected are connected in parallel with each other. Further, the power supply circuit 9 has an output voltage limit characteristic for controlling the output voltage to be lower than the set voltage.

[0012] The charger of the present invention cleverly utilizes the difference in charging characteristics between a primary battery and a secondary battery to prevent the adverse effect of charging the primary battery. When the voltage is continuously applied to the primary battery, the battery voltage gradually increases and becomes higher than that of the secondary battery, and furthermore, the battery exhibits unique physical properties in which the internal resistance gradually decreases. ADVANTAGE OF THE INVENTION The battery charger of this invention prevents the bad effect at the time of charging of the primary battery erroneously installed with a secondary battery with a very simple circuit by utilizing the characteristic peculiar to a primary battery.

Since the battery voltage rises when the primary battery is charged, the charger of the present invention has an output voltage limit characteristic for limiting the output voltage of the power supply circuit 9 to 1.8 ± 0.1 V, for example. . Furthermore, in order to effectively utilize the characteristic that the internal resistance of the primary battery decreases when charged, a voltage dividing constant resistance 12 is connected in series with each battery. Since the internal resistance of the primary battery decreases as the battery is charged, the voltage applied to the battery gradually decreases due to the voltage dividing constant resistance 12 connected in series. This is because the voltage applied to the battery and the voltage dividing constant resistance 12 is limited to a constant value by the output voltage limit characteristic, and the voltage applied to the voltage dividing constant resistance 12 gradually increases. Therefore, the battery charger of the present invention does not charge until the battery voltage becomes abnormally high even if the primary battery is erroneously mounted, and also controls the voltage applied to the battery to gradually decrease due to the decrease in the internal resistance. Thus, the adverse effects of charging are effectively prevented.

Further, the battery charger according to claim 2 of the present invention has a mounting portion 4 to which the AA or AAA type secondary battery 1 can be removably mounted.

In the battery charger according to a third aspect of the present invention, the battery to be charged is either a nickel-hydrogen battery or a nickel-cadmium battery, and the set voltage of the output voltage limit characteristic of the power supply circuit 9 is 1. 8 ± 0.1V.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify a charger for embodying the technical idea of the present invention, and the present invention does not limit the charger to the following.

Further, in this specification, in order to make it easier to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”.
However, the members described in the claims are not limited to the members of the embodiments.

The charger shown in the perspective view of FIG. 1 and the cross-sectional view of FIG. The printed circuit board 3 is built in the bottom of the case 2 and fixes an electronic part 16 for realizing a charging circuit.

The case 2 is a plastic upper case 2
A and a lower case 2B, and the upper case 2A is provided with a mounting portion 4 on the upper surface for mounting the secondary battery 1 in a detachable manner. The mounting section 4 mounts both AA batteries and AAA batteries. The mounting portion 4 is formed in a groove shape with an open top, and mounts four cylindrical batteries side by side. A partition 6 is provided vertically between the four cylindrical batteries. Furthermore, the mounting part 4
Is equipped with a switching table 5 on the + side of the battery in order to mount AA batteries and AAA batteries having different lengths.

The switching stand 5 has a charging contact 8 fixed at a position in contact with the positive electrode of the battery. The switching table 5 is connected to the upper case 2A so as to be movable in the vertical direction with respect to the battery. The switching table 5 elastically presses the positive electrode of the battery via an elastic body 14 such as a spring. When a long AA battery is mounted on the mounting portion 4, the switching table 5 is pressed by the positive electrode of the battery and is pushed into the upper case 2A. When a short AAA battery is mounted, the switching table 5 is pushed out by the elastic body 14 and presses the battery. The battery charger of this structure has AA batteries and AAA
It can be charged by attaching a battery.

In FIG. 2, the upper case 2A is provided with the mounting portion 4 on the left side, and the right side is formed to be high to accommodate the electronic parts 16 for realizing the charging circuit. Upper case 2A
The charging circuit component mounted on the printed circuit board 3 is incorporated in a portion to be formed at a high height. The lower case 2B is provided with an outlet 7 by molding substantially the entire bottom surface into a planar shape. The outlet 7 is connected to the printed circuit board 3.

The printed circuit board 3 is connected to a charging contact 8 exposed on the mounting portion 4 of the upper case 2A. Charging contacts 8
Is electrically connected to the secondary battery 1 set in the mounting section 4 to charge the secondary battery 1. The negative charging contact 8 is
It is connected to the printed circuit board 3 via a lead wire (not shown) or the like. The positive charging contact 8 fixed to the switching table 5 is
It is connected to the printed circuit board 3 via a metal elastic body 14 and a metal plate 15 to which one end of the elastic body 14 is fixed.

FIG. 3 shows a charging circuit mounted on the printed circuit board 3. The charging circuit shown in FIG. 1 includes a power supply circuit 9 for converting an input commercial power supply into a charging voltage for the secondary battery 1, a voltage feedback circuit 10 for realizing an output voltage limit characteristic of the power supply circuit 9, and a stabilization circuit. And a voltage dividing constant resistor 12 connected between the negative charging contact 8 of the secondary battery 1 and the ground.

The power supply circuit 9 is a switching power supply. This power supply circuit 9 is a switching element that rectifies a commercial power supply with a diode and converts it into a direct current.
Hz, the AC is stepped down to the charging voltage of the secondary battery 1 by a transformer, and the output of the transformer is rectified to DC. The switching power supply can control the output voltage by controlling the duty for switching the switching element on and off.
When the on-time is longer than the off-time, the output voltage increases. Conversely, when the on-time is shortened, the output voltage decreases.

A signal for controlling the duty of the switching element is input from the voltage feedback circuit 10 to realize the output voltage limit characteristic of the power supply circuit 9. The power supply circuit 9 having the output voltage limit characteristic adjusts the set voltage to be output to an optimum voltage according to the type of the secondary battery 1 to be charged. The setting voltage of the charger that uses the nickel-cadmium battery or the nickel-hydrogen battery as the secondary battery 1 to be charged is 1.8 ± 0.1V. This is because the charged nickel-hydrogen battery or nickel-cadmium battery can be fully charged at this voltage, and the adverse effects due to charging of the alkaline battery incorrectly set as the secondary battery 1 can be effectively prevented.

The power supply circuit 9 shown in FIG. 3 is controlled by a regulator circuit 11 and a voltage feedback circuit 10 that stabilize the output voltage, and realizes an output voltage limit characteristic. The regulator circuit 11 has a stabilized output voltage of 5 V, for example. The regulator circuit 11
Since the output current is extremely small, it can be realized with a regulator IC. The regulator circuit 11 is an electronic circuit other than the power supply circuit 9 built in the charger, for example,
Used as a power supply for driving a protection circuit and the like.

The output voltage of the regulator circuit 11 is divided and supplied to the voltage feedback circuit 10. The voltage feedback circuit 10 includes a differential amplifier 13 that controls a switching element of the power supply circuit 9. In the differential amplifier 13, the divided voltage of the regulator circuit 11 is applied to a positive input terminal. The power supply circuit 9 is connected to the negative input terminal.
Is divided and input. The differential amplifier 13 having this circuit configuration compares the output voltage of the power supply circuit 9 with the stabilized output voltage of the regulator circuit 11, amplifies the comparison voltage, and supplies the amplified voltage to the power supply circuit 9 as a switching power supply.

When the output voltage of the power supply circuit 9 becomes higher than the set voltage, the output voltage of the differential amplifier 13 becomes lower. When the output voltage of the differential amplifier 13 decreases, this signal causes the switching element of the power supply circuit 9 to shorten the on-time with respect to the off-time, that is, reduce the duty to decrease the output voltage. For this reason, the power supply circuit 9 realizes output voltage limit characteristics.

The power supply circuit 9 shown in the figure sets the duty of the switching power supply to realize output voltage limit characteristics. The power supply circuit does not necessarily need to be a switching power supply. For example, although not shown, a so-called series-type power supply circuit may be used in which a commercial power supply is stepped down to a charging voltage by a transformer, converted into direct current, and a control transistor for controlling the voltage is provided on the output side. This power supply circuit controls the internal resistance of the control transistor to realize output voltage limit characteristics. The control transistor is
When the output voltage becomes higher than the set voltage, the internal resistance is increased to lower the output voltage. When the output voltage decreases, the internal resistance of the control transistor is reduced, and the output voltage is set as the set voltage.

The dividing resistor 12 is composed of four resistors, and the four negative charging contacts 8 are connected to the ground via the dividing resistor 12. Each voltage divider 12 reduces the voltage applied to the incorrectly set primary battery. Further, the voltage dividing constant resistance 12 limits the charging current of the secondary battery 1. The voltage dividing constant resistance 12 is set to, for example, several Ω. When the resistance value of the voltage dividing constant resistor 12 is increased, the voltage applied to the primary battery decreases. However, the charging current of the secondary battery 1 also decreases. Conversely, when the voltage dividing constant resistance 12 is reduced, the voltage applied to the primary battery increases, and the charging current increases. The voltage dividing constant resistance 12 is set to an optimum value in consideration of the voltage applied to the primary battery set incorrectly and the charging current. For example, in a charger for charging AA batteries, AAA battery type nickel-cadmium batteries and nickel-hydrogen batteries, the voltage division constant resistance 12 is set to 2 to 3Ω.

In the battery charger of the present invention, the power supply circuit 9 is provided with an output voltage limit characteristic. Further, since each battery is connected to the voltage dividing constant resistance 12 in series, the power supply circuit 9 controls the output current. It is not necessary to provide a current feedback circuit for performing the operation. This is also effective in making the charging circuit a simple circuit configuration.

[0032]

The charger for charging a plurality of secondary batteries according to the present invention has an extremely simple circuit, and effectively identifies the primary battery that is erroneously mounted as a secondary battery and effectively eliminates the adverse effect of charging the primary battery. Can be prevented. This is because the charger of the present invention has a voltage dividing constant resistance connected in series with each secondary battery in addition to providing the power supply circuit with output voltage limiting characteristics.

The primary battery and the secondary battery have different electrical characteristics when charged. The voltage of the primary battery is higher than that of the secondary battery when the battery is continuously charged. However, by limiting the charging voltage, it is possible to prevent adverse effects such as liquid leakage of the charged primary battery. The voltage for preventing the harmful effects of the charged primary battery is, for example, a voltage that can sufficiently charge the secondary battery. For this reason, by giving the output voltage limit characteristic to the power supply circuit, it is possible to prevent the harmful effect of charging the incorrectly set primary battery. However, only by this, the primary battery cannot be sufficiently safely prevented from the adverse effects of charging, and therefore, the charger of the present invention further utilizes the unique characteristics of the primary battery to more safely prevent the adverse effects of charging. To prevent. Since the primary battery has a property that the internal resistance is reduced when the voltage is continuously applied, the charger of the present invention connects the voltage dividing constant resistance in series with the battery, and when the voltage is continuously applied, the primary battery is connected to the primary battery. This voltage is reduced. Even if the internal resistance of the primary battery is reduced, the voltage dividing constant resistance is constant, and the charger of the present invention, which controls the voltage applied to the primary battery and the voltage dividing constant resistance to be constant, when the voltage is continuously applied In addition, the voltage applied to the primary battery is lowered to effectively prevent the adverse effects of charging. Therefore, the battery charger of the present invention realizes a feature that a primary battery set incorrectly can be extremely safely prevented from being adversely affected by charging.

[Brief description of the drawings]

FIG. 1 is a perspective view of a charger according to an embodiment of the present invention.

FIG. 2 is a sectional view of the charger shown in FIG. 1;

FIG. 3 is a circuit diagram of a charging circuit of the charger according to the embodiment of the present invention.

[Explanation of symbols]

1 ... secondary battery 2 ... case 2A ... upper case 2B ...
Lower case 3 ... Printed circuit board 4 ... Mounting section 5 ... Switching board 6 ... Bulkhead 7 ... Outlet 8 ... Charging contact 9 ... Power supply circuit 10 ... Voltage feedback circuit 11 ... Regulator circuit 12 ... Voltage dividing constant resistance 13 ... Differential amplifier 14 ... Elastic body 15 ... Metal plate 16 ... Electronic parts

Claims (3)

[Claims] 1. A rechargeable battery having a mounting portion (4) for detachably mounting a plurality of rechargeable batteries (1), mounted on the mounting portion (4).
In the charger for charging (1) at the same time, a voltage dividing constant resistance (12) is connected in series with a plurality of secondary batteries (1), and the secondary battery (12) to which the voltage dividing constant resistance (12) is connected. 1)
A power supply circuit with output voltage limit characteristics that is connected in parallel with each other and controls the output voltage below the set voltage (9)
A charger for charging a plurality of secondary batteries, wherein the charger is connected to a battery. 2. A plurality of rechargeable batteries according to claim 1, wherein AA or AAA type rechargeable batteries (1) can be removably mounted on the mounting portion (4). Charger. 3. The battery to be charged is either a nickel-metal hydride battery or a nickel-cadmium battery, and the set voltage of the output voltage limit characteristic of the power supply circuit (9) is 1.8 ± 1.8.
The charger for charging a plurality of secondary batteries according to claim 1, which is at 0.1 V.