JPH09285030A - Battery pack and charging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the abnormal heat generations of individual batteries and prevent the fusions of temperature fuses from being caused by a short circuit current. SOLUTION: In respective batteries B1-B8 stored in a battery pack 50, temperature fuses H1-H8 are provided respectively, and the temperature fuses H1-H8 are connected in series with each other. The temperature fuse H1 is connected with one terminal of a thermistor TM to connect the other terminal of the thermistor TM with a detecting terminal T7. Accordingly, the fusions of the temperature fuses caused by the abnormal heat generations of the individual batteries B1-B8 can be detected by a CPU 21 of a charging control circuit 20. Also, even when the short circuit of an input terminal T6 and the detecting terminal T7 occurs, since the short circuit current can be restricted by the resistance of the thermistor TM, the fusions of the temperature fuses H1-H8 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage battery pack and a charging device capable of detecting abnormal heat generation of a storage battery.

[0002]

2. Description of the Related Art Conventionally, the charging device shown in FIG. 6 has been known. As shown in FIG. 6, this one supplies a charging current I from a DC power supply circuit 14 to a storage battery pack 80 accommodating a plurality of storage batteries 82 for charging, and any one of the plurality of storage batteries 82 described above. Is provided with a temperature fuse 84 that is blown by the abnormal heat generation of the storage battery. Further, a thermostat 86 that opens and closes due to the heat generation of the storage battery 82 is connected in series to the temperature fuse 84. The change in the voltage between the input terminals T7 and T8 due to the opening and closing of the thermostat 86 changes the output terminal T.
It is detected by the charge control circuit 20 via 4 and T5.
Then, normally, the supply of the charging current I is stopped by opening the thermostat 86, and when the storage battery 82 abnormally generates heat, the temperature fuse 84 is melted and the supply of the charging current I is stopped. .

[0003]

However, in the conventional battery described above, since one storage battery of the plurality of storage batteries 82 is provided with the thermal fuse 84, another storage battery 84 not provided with this thermal fuse 84 is provided. Even if abnormal heat is generated, it takes time until the heat is conducted to the thermal fuse 84, so there is a problem that the abnormal heat cannot be detected early. Moreover, when the input terminals T6 and T7 are short-circuited, there is a problem that the thermal fuse 84 is blown and the storage battery 82 cannot be charged even though the storage battery is not abnormally heated.

The present invention has been made in order to solve the above problems, and an object of the present invention is to detect abnormal heat generation of each storage battery at an early stage and to detect a blowout of a temperature fuse and a charging terminal. This is to prevent the thermal fuse from being blown out even when the terminal of is short-circuited.

[0005]

In order to achieve the above-mentioned object, the present invention provides a storage battery pack having a plurality of storage batteries, wherein each of the plurality of storage batteries has a thermal fuse. The temperature fuses are provided and are connected in series with each other, and the thermistor is connected in series with the temperature fuses connected in series. The technical means is employed in which a detection terminal for detecting the fusing of the above is detected through the thermistor.

According to a second aspect of the invention, there is provided a charging device for charging the plurality of storage batteries according to the first aspect, wherein any one of the thermal fuses is blown by electrically connecting to the detection terminal. The technical means that a detection means for detecting is provided.

[0007]

In the invention described in claim 1 or 2, since a thermal fuse is provided in each of the plurality of storage batteries, even if any of the storage batteries abnormally heats up,
The abnormal heat generation can be detected from the detection terminal. Moreover, since the temperature fuses are connected in series with each other and the thermistor is connected in series with the temperature fuses connected in series, the short circuit current flows from the detection terminal to the temperature fuse through the thermistor. Even if the current flows, the short-circuit current is limited by the resistance of the thermistor, so that the thermal fuse can be prevented from being blown. Therefore, it is possible to prevent the thermal fuse from being blown out due to a short circuit of the input terminal, and it is possible to prevent the storage battery that has not abnormally generated heat from becoming unusable.

Particularly, in the invention described in claim 2, it is possible to realize a charging device capable of detecting the fusing of the temperature fuse by charging the storage battery and electrically connecting it to the detection terminal. You can

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory perspective view showing the appearance of a storage battery pack according to an embodiment of the present invention, and FIG.
1 is an external view showing a state in which a thermal fuse is attached to the storage battery housed in the storage battery pack shown in FIG.
FIG. 4 is a block diagram showing a main circuit configuration of the storage battery pack shown in FIG. 4 and the charging device shown in FIG. 4, and FIG. 4 is an external perspective explanatory view of the charging device charging the storage battery pack shown in FIG. In addition, in the present embodiment, a charging device that charges a storage battery of a rechargeable electric tool represented by an electric drill, an electric screwdriver, and the like will be described as an example. Further, it is assumed that the battery is charged using 100V commercial AC power.

First, the main structure of the storage battery pack will be described. As shown in FIG. 1, the storage battery pack 50 is provided with an outer case 51 having a rectangular cross section and having an upper surface opening.
Inside the outer case 51, a lower accommodating portion 52 having a rectangular cross section accommodating six columnar storage batteries B made of nickel cadmium shown in FIG. On the lower accommodation portion 52, two storage batteries B are accommodated, and the upper accommodation portion 5 having an oval cross section and a columnar shape.
3 are provided, and on the outer peripheral surfaces of the upper housing portion 53 that face each other, the input terminals T6 and T8 that receive the supply of the charging current I, the detection of detecting the melting of the temperature fuse H and the temperature of the storage battery, which will be described later, are detected. And a terminal T7.

A plate-shaped guide member 54 is formed on the outer peripheral surface of the lower portion of the input terminal T8 so as to project. The guide member 54 is formed on the inner surface of the insertion port 42 of the charging device 10 shown in FIG. It is slid and fitted into the guide groove 44. That is, when the storage battery pack 50 is charged by the charging device 10, the upper accommodation portion 53 is prevented from being inserted into the insertion opening 42 in the wrong orientation. Further, locking claws 55 (one of which is not shown) are provided on opposite side surfaces of the outer case 51, and as shown in FIG. 5, the storage battery pack 50 is placed inside the grip 74 of the electric drill 70. It is adapted to be locked by a member (not shown) formed at the lower end of the grip 74 when the grip 74 is loaded.

As shown in FIG. 2, a thermal fuse H is attached to the storage battery B with an adhesive or the like, and lead wires 32 and 34 are connected to the thermal fuse H. The thermal fuse H, as shown in FIG.
Storage batteries B1 to B8 are attached to all of them, and the temperature fuses H1 to H8 are connected in series with each other by lead wires 32 and 34. One end of the thermal fuse H8 is connected to the electric path 55 that connects the storage battery B8 and the input terminal T8, and the thermal fuse H1
Is connected in series with the thermistor TM. The thermistor TM is connected to the detection terminal T7.

As described above, according to the present storage battery pack 50, since the temperature fuses H1 to H8 are attached to all the storage batteries B1 to B8, when any one of the storage batteries B1 to B8 abnormally heats up. Even if there is, the heat can blow the thermal fuse attached to the storage battery. Therefore, by detecting the voltage between the detection terminal T7 and the input terminal T8, it is possible to detect the melting of any one of the temperature fuses. Moreover, for example, even when the input terminal T6 and the detection terminal T7 contact with a nail or the like and short-circuits, the short-circuit current is limited by the resistance of the thermistor TM, so that the thermal fuse is prevented from being blown. Therefore, it is possible to prevent the storage battery pack 50 that does not generate abnormal heat from becoming unchargeable.

Next, the main circuit configuration of the charging device 10 will be described with reference to FIG. As shown in FIG. 3, the present charging device 10 is provided with connection terminals (power plugs) T1 and T2 connected to a commercial AC power supply 12 of 100V. Further, the charging device 10 is provided with output terminals T3 and T5 electrically connected to the input terminals T6 and T8 provided in the storage battery pack 50, and a terminal T4 electrically connected to the detection terminal T7. Has been. A DC power supply circuit 14 for converting an AC current of 100 V into a DC current is connected to the connection terminals T1 and T2, and a charging current I is supplied between the DC power supply circuit 14 and the output terminal T3. A switch element 18 composed of an FET or a transistor for stopping the supply is connected.

Between the terminal T4 and the output terminal T5, the voltage between the terminal T4 and the output terminal T5 is detected to detect that the storage battery pack 50 is connected to the charging device 10, and the temperature fuses H1 to H8. A charge control circuit 20 including a CPU 21 and the like for detecting that any of the above has been melted and controlling the charge current I is connected. The charge control circuit 20 is connected to the switch element 18, and controls ON / OFF of the switch element 18. Further, the DC power supply circuit 14 is connected to a constant voltage circuit 16 that converts the voltage supplied from the DC power supply circuit 14 into a constant voltage. The constant voltage circuit 16 is connected to the charging control circuit 20. There is.

Next, the operation of each circuit when the storage battery pack 50 is charged using the charging device 10 having the above-mentioned configuration will be described with reference to FIG. The storage battery pack 50 is
It is assumed that the thermistor TM has been sufficiently naturally cooled and the temperature of the thermistor TM has not risen. First, when the storage battery pack 50 is loaded into the charging device 10, the voltage divided by the resistance R1 and the resistance of the thermistor TM is detected by the CPU 21 in the charging control circuit 20 via the terminal T4. Then
A switch ON signal is output from the CPU 21 to the switch element 18, and the charging current I is output from the output terminal T3 to the input terminal T6.
Through the storage batteries B1 to B8 to start charging the storage batteries B1 to B8.

Here, if the storage battery B2 abnormally generates heat, the temperature fuse H2 attached to the storage battery B2 is blown by the heat, so that the voltage at the terminal T4 becomes
It rises to a voltage value equal to the output voltage of the constant voltage circuit 16.
Then, the change is detected by the CPU 21 and the CP
A switch OFF signal is output from U21 to the switch element 18, and the supply of the charging current I is stopped. On the other hand, in the case where the above-mentioned abnormal heat generation does not occur in any of the storage batteries and the batteries are normally charged, the voltage at the terminal T4 is reduced due to the decrease in the resistance value of the thermistor TM accompanying the temperature rise when the storage batteries are fully charged. Since the voltage value changes according to the temperature when fully charged,
This change is detected by the CPU 21, and the switch element 1
8 is turned off, and the supply of the charging current I is stopped.

As described above, according to the present charging device 10, it is possible to detect the abnormal heat generation of one of the storage batteries B1 to B8 housed in the storage battery pack 50 and stop the charging.

As shown in FIG. 5, the storage battery pack 50, which is normally charged and fully charged, is provided with a storage space 72 formed inside a grip 74 of the electric drill 70.
The guide 52 is accommodated therein by sliding the guide 52 into a guide groove 72 formed in the accommodation space 72. And
The electric drill 70 receives electric power from the storage battery pack 50 and rotates the rotating unit 76. In addition, although the plate-shaped one is shown as the temperature fuse in the above-mentioned embodiment, other shapes such as a thread-shaped one can be used. Further, the CPU 21 functions as a detection unit according to the present invention.

[0020]

As described above, according to the present invention, since each storage battery is provided with a temperature fuse, even if any of the storage batteries abnormally generates heat, the abnormal heat generation can be detected. You can Moreover, since a thermistor is connected to these temperature fuses, even if a short circuit current flows through the temperature fuse, the short circuit current is limited by the resistance of the thermistor.
It is possible to prevent the thermal fuse from being blown. Therefore, it is possible to prevent the storage battery that does not generate abnormal heat from becoming unusable due to the melting of the thermal fuse.

[Brief description of drawings]

FIG. 1 is an external perspective view illustrating a storage battery pack according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing a state in which a thermal fuse is attached to a storage battery housed in a storage battery pack.

FIG. 3 is a block diagram showing main circuit configurations of a charging device and a storage battery pack according to an embodiment of the present invention.

FIG. 4 is an external perspective view of the charging device.

FIG. 5 is an external view of an electric drill equipped with a storage battery pack.

FIG. 6 is a block diagram showing main circuit configurations of a conventional charging device and a storage battery pack.

[Explanation of symbols]

 10 Charging Device 20 Charging Control Circuit 21 CPU 50 Storage Battery Pack B1 to B8 Storage Battery H1 to H8 Temperature Fuse TM Thermistor T7 Detection Terminal

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H02H 7/18 H02H 7/18 H02J 7/00 H02J 7/00 S (72) Inventor Tomoyasu Kasuya Aichi Makita, 3-11-8, Sumiyoshi-cho, Anjo City, Japan

Claims (2)

[Claims] 1. A storage battery pack having a plurality of storage batteries, wherein each of the plurality of storage batteries is provided with a temperature fuse, and the temperature fuses are connected in series to each other, and A thermistor is connected in series to the temperature fuse connected to, and a detection terminal for detecting the fusing of any of the plurality of temperature fuses through the thermistor is provided. 2. A charging device for charging the plurality of storage batteries according to claim 1, further comprising a detection unit that electrically connects to the detection terminal to detect melting of any one of the temperature fuses. Charging device characterized in that