JP2000294099A - Thermal protector and battery pack using this thermal protector - Google Patents

Abstract

(57) [Problem] To provide a manual reset type thermal protector with high safety. SOLUTION: A plunger 4 is provided in a resin block 3 serving also as a reset button 2 inside a container 1 having a locked portion 11 on an inner surface. First and second coil springs 6 and 7 are arranged in series at one end of a plunger 4 via a metal plate 5, and a locking portion locked to a locked portion 11 is provided on the second coil spring side. A leaf spring 8 having one end 10 is arranged. Further, a thermally responsive element 9 is provided, the one end of which is separated from the locked portion 11 by the curved reversal operation between the metal plate 5 and the leaf spring 8. Further, the first and second movable electrodes 12a and 12b are provided on the metal plate 5, and the movable electrodes 12a and 12b are provided.
12b, the first and second fixed electrodes 13a, 13a
3b is provided on the support 14 inside the container 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal protector for preventing burnout of electrical equipment due to overheating and overcurrent, and a secondary battery pack containing the same.

[0002]

2. Description of the Related Art A self-recovering type thermal protector includes a movable electrode having a thermally responsive element that performs an inversion operation by heat,
A fixed electrode is provided facing the movable electrode, and is provided so as to be able to contact and separate from the movable electrode. Then, the thermo-responsive element reverses to open the contact point between the movable electrode and the fixed electrode, cut off the power supply, and protect the device.
Then, when the abnormality of the electric device is removed and the temperature of the thermal responsive element falls, the thermal responsive element performs an inverting operation again and restarts power supply. As described above, the self-recovering type thermal protector does not need to be replaced and can detect an abnormality in an electric device, and is used as one of safety elements having a great advantage different from a fuse.

As shown in FIG. 9, a conventional thermal protector includes a fixed electrode support 27 and a thermally responsive element support 28 fixed to a resin block 26 in a container 25, and one end of the fixed electrode support 27. A fixed electrode 29 connected;
The thermal responsive device 30 includes a thermal responsive device 30 connected to one end of the thermal responsive device support portion 28 and a movable electrode 31 provided at one end of the thermal responsive device 30. Lead wires 32 are respectively connected to the other end portions of the fixed electrode support portion 27 and the thermally responsive device support portion 28, and each lead wire 32 is led out of the container 25 to the outside. The resin block 26 is fixed in the container 25 with the filler 15.

[0004]

Such a conventional self-recovering type thermal protector is currently used in the field of secondary battery packs for relatively low current capacity devices such as mobile phones. On the other hand, in the case of equipment with a large current capacity represented by electric tools, etc., the self-recovery type is not suitable from the viewpoint of safety. Due to the fact that the rated current is excessively large for the required shape and dimensions, there has been no suitable thermal protector for secondary short-circuits, and a highly safe thermal protector has been desired.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a manual return type thermal protector with high safety.

[0006]

According to a first aspect of the present invention, there is provided a thermal protector including a fixed electrode, a movable electrode, and a movable electrode with respect to the fixed electrode in a container having a locked portion on an inner surface. One end has a plunger for bringing the electrode into and out of contact, an elastic body arranged in the axial direction of the plunger, and a locking portion supported by the plunger and locked to the locked portion of the container. An elastic plate, and a thermally responsive element for releasing the locking portion of the elastic plate from the locked portion of the container by a bending inversion operation, wherein the locking portion of the elastic plate is separated from the locked portion of the container. Along with this, by moving the plunger in the axial direction by the extension action of the elastic body, the contact state between the fixed electrode and the movable electrode is released to separate the fixed electrode and the movable electrode, Keep this separated state It has a configuration that.

[0007] With this configuration, the elastic plate is pushed down by the reversing operation of the thermoresponsive element accompanying the temperature rise of the device, and the locking portion of the elastic plate is separated from the locked portion of the container. At this time, the plunger moves due to the extension of the elastic body, the contact state between the fixed electrode and the movable electrode is released and separated, and the circuit is cut off.

Next, after removing the abnormal state of the device, the reset button is pushed back to a position where the locking portion of the elastic plate and the locked portion are locked, and then the contact point between the fixed electrode and the movable electrode is returned. Is closed and power can be supplied.

According to a second aspect of the present invention, in the thermal protector according to the first aspect, the elastic body and the fixed electrode include first and second coil springs and first and second fixed electrodes, respectively. , The first and second fixed electrodes are fixed at a fixed distance within a support, and
The first coil spring is embedded in the support between the first and second fixed electrodes, and the movable electrode is composed of first and second movable electrodes, each fixed to a conductive plate at a certain distance. And the first and second fixed electrodes and the first and second movable electrodes each take the form of a double-break type contact that is opposed to each other in pairs, and the second coil spring is formed of the conductive material. And the first coil spring is arranged in series and is supported by one end of the plunger.

With this structure, the fixed contact and the movable contact can be brought into contact with and separated from each other by driving the conductive plate on which the movable contact is formed by the expansion and contraction of the first coil spring. A load can be applied to the plate to generate a contact pressure between the fixed contact and the movable contact.

According to a third aspect of the present invention, in the thermal protector according to the first or second aspect, the plunger is fixed to a block having a convex portion, and the convex portion is led out of the container. A reset button is provided for returning the separated state between the fixed electrode and the movable electrode to a contact state.

With this configuration, in the state where the contact between the fixed electrode and the movable electrode is separated, the contact can be returned to the contact state again by pushing back the reset button led out of the container.

According to a fourth aspect of the present invention, in the thermal protector according to any one of the first to third aspects, the other end of the elastic plate where the locking portion is not formed is abutted against and supported by a part of the block. It has the configuration that has been done.

With this configuration, the stability of the elastic plate in a stationary state is increased, and the contact pressure between the fixed electrode and the movable electrode can be stabilized.

According to a fifth aspect of the present invention, in the thermal protector according to any one of the first to fourth aspects, the thermally responsive element has a configuration provided near a contact point between the fixed electrode and the movable electrode. .

With this configuration, the sensitivity of the device to self-heating due to overcurrent of the device can be improved by arranging the thermally responsive element closer to the contact between the fixed electrode and the movable electrode, that is, to the heating portion that is energized. it can.

According to a sixth aspect of the present invention, in the thermal protector according to any one of the first to fifth aspects, the end of the locking portion of the elastic plate has a curved shape.

According to this configuration, the abrasion resistance due to the sliding between the locked portion and the locking portion can be improved.

According to a seventh aspect of the present invention, in the thermal protector according to any one of the first to sixth aspects, the locking portion of the elastic plate and the locked portion of the container are made of resin or metal. Have.

According to this configuration, the abrasion resistance due to the sliding between the locked portion and the locking portion can be improved.

According to an eighth aspect of the present invention, in the thermal protector according to any one of the first to seventh aspects, a concave portion or a convex portion is formed on a part of the side where the reset button is led out. Have.

With this configuration, the thermal protector can be easily attached to an arbitrary position by fitting using the concave portion or the convex portion.

According to a ninth aspect of the present invention, the battery pack includes a plurality of battery packs.
9. A battery pack containing a secondary battery, wherein the battery pack contains:
The thermal protector according to any one of the above is connected in series to a battery circuit, the separated state between the fixed electrode and the movable electrode of the thermal protector is in a contact state, and the off state of the battery circuit is in an on state. It has a configuration in which a reset button is provided.

With this configuration, when an abnormality such as a secondary short circuit of the secondary battery occurs, the fixed electrode and the movable electrode are separated from each other, and the battery circuit can be cut off (off state).
Thereafter, the reset button is pushed back to bring the fixed electrode and the movable electrode into contact with each other, whereby the battery circuit can be turned on (on) and the power supply can be resumed.

According to a tenth aspect of the present invention, in the battery pack of the ninth aspect, an uneven portion is formed on an inner surface of the battery pack, and the unevenness is formed on the inner surface of the container of the thermal protector according to the eighth aspect. When the battery pack is fitted, the thermal protector is held in the battery pack.

With this configuration, the thermal protector can be mounted in the battery pack with one touch.

According to an eleventh aspect of the present invention, in the battery pack according to any one of the ninth and tenth aspects, when the fixed electrode and the movable electrode are in contact with each other, the tip of the reset button has an outer surface of the battery pack. It has a configuration that is located more inside.

According to this configuration, when the battery pack is used by attaching it to a predetermined device, the reset button of the thermal protector can be prevented from hindering the operation.

According to a twelfth aspect of the present invention, there is provided the battery pack according to any one of the ninth to eleventh aspects, wherein the battery pack has a cap attached to the through hole and operable to operate the reset button. ing.

With this configuration, the battery pack can be protected from moisture, dust, etc., which may enter through the through-holes of the battery pack, which may adversely affect the secondary battery and the thermal protector inside the battery pack. it can.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a thermal protector according to a first embodiment of the present invention includes a reset button inside an insulating container 1 made of a resin such as PBT (polybutylene terephthalate). A plate-like plunger 4 made of a metal such as aluminum is provided on a resin block 3 also serving as 2 in the same direction as the central axis of the container 1. A first coil spring 6 and a second coil spring 7 are arranged in series at one end of the plunger 4 via a metal plate 5 such as copper in a coaxial direction with the center axis of the container 1. A metal leaf spring 8 made of elastic material such as copper is arranged on the spring side. Here, the leaf spring may be an elastic plate, and is not limited to a leaf spring. Further, one end is sandwiched between the metal plate 5 and the leaf spring 8, and the other end is provided with a conductive heat responsive element 9 having a function of pushing down the leaf spring 8 in the direction of the arrow A by reversing operation. Further, a locking portion 10 formed in a curved shape is provided at one end of the leaf spring 8,
One end of the locking portion 10 is housed in a stepped portion of the locked portion 11 formed at a predetermined position on the inner surface of the container 1, while the other end where the locking portion is not formed has an L-shape. And is supported by being in contact with one end of the resin block 3 extending to the end. Metal plate 5
Are provided with first and second movable electrodes 12a and 12b made of silver or the like, respectively. Further, the first and second fixed electrodes 13a, 1
One end of 3b is a support 14 having an insulating property such as resin.
And the other end is led out of the container 1. One end of the first coil spring 6 is embedded in a hole provided in the center of the support 14. The first and second movable electrodes 12a and 12b are connected to the first and second fixed electrodes 1 respectively.
3a and 13b, respectively, and the first and second movable electrodes 12
a, 12b and first and second fixed electrodes 13a, 13b
Contact pressure is generated between the contact and the contact, and the contact keeps the contact state,
As a result, a current path from the external end of the fixed electrode 13a to the external end of the fixed electrode 13b is sequentially formed through the movable electrode 12a, the metal plate 5, and the movable electrode 12b. Here, the current may flow in a direction opposite to the current path. Note that the container 1 is sealed with a support 14 and a filler 15.

Next, the operation of the thermal protector will be described.

When the temperature of a device (not shown) rises due to an overcurrent or an excessive rise in temperature, the thermally responsive element 9 bends inward, thereby causing the leaf spring 8 to move as shown in FIG. When the operating temperature of the thermally responsive element 9 reaches a predetermined temperature and the amount of pushing of the thermally responsive element 9 exceeds the step width of the locked portion 11, the leaf spring is pushed. 8 is separated from the locked portion 11. At this moment, as shown in FIG. 2, the first coil spring 6 and the second coil spring 7 urged in the extension direction extend, and the metal plate 5 and the plunger 4 move in the extension direction. The first and second movable electrodes 12a and 12b attached to the metal plate 5 are first and second fixed electrodes 13
a, 13b to be separated from each other, open the contact and cut off the current path. As a result, the end of the resin block 3, that is, the reset button 2, projects out of the container 1 by the sum of the extension distances of the first coil spring 6 and the second coil spring 7.

After the operation of the thermal protector, it is confirmed that the abnormal state of the device has been removed, and the reset button 2 is pushed back to a position where the locking portion 10 is fitted in the locked portion 11. The first fixed electrode 13a and the first movable electrode 12a, and the second fixed electrode 13b and the second movable electrode 12b are in contact with each other, the contacts are closed again, and power can be supplied.

The bending operation of the thermoresponsive element 9 is performed by the leaf spring 8.
The leaf spring 8 may be provided with a protrusion in order to transmit the vibration efficiently. In addition, the bending operation of the thermally responsive element 9 may be either a snap action or a slow action. Further, in the present embodiment, the case where the container 1 and the support 14 are sealed with the filler 15 has been described, but the container 1 and the support 14 can be fixed using ultrasonic waves.

As shown in FIG. 3, a thermal protector according to a second embodiment of the present invention has the same configuration as that of the thermal protector shown in FIG.
The portion where the locking portion 10 of the leaf spring 8 contacts the locked portion 11 of the container 1 has a curved end portion made of a resin such as PBT (polybutylene terephthalate).

According to the second embodiment, the locking portion 1
It is possible to improve the wear resistance due to the sliding between the lock portion 11 and the locked portion 11.

As shown in FIG. 4, the thermal protector according to the third embodiment of the present invention has the same configuration as that of the thermal protector shown in FIG.
That is, the metal body 16 is disposed on the locked portion 11 of the container 1 and the sliding portion around the locked portion 11.

According to the third embodiment, the locking portion 1
It is possible to improve the wear resistance due to the sliding between the lock portion 11 and the locked portion 11.

As shown in FIG. 5, the thermal protector according to the fourth embodiment of the present invention has the same configuration as that of the thermal protector shown in FIG.
This is the shape of the container 1, and two convex portions 17 are formed on the outer surface of the container 1 on the side from which the reset button of the container 1 is extended.

According to the fourth embodiment, the projection 17
By using the method described above, a concave portion is separately provided in the mounted portion, and the thermal protector can be easily mounted on an arbitrary portion of the mounted portion by fitting the two.

Although FIG. 5 shows an example of the convex portion, it goes without saying that a concave portion may be formed on the thermal protector side if a convex portion is formed on the mounting portion. Further, if a screw is cut on the outer surface of the cylindrical container convex portion surrounding the reset button of the thermal protector (not shown), it is possible to easily realize the screw-on type mounting on the mounting portion.

As shown in FIG. 6, the structure of the battery pack according to the fifth embodiment of the present invention is such that
The thermal protector 19 according to any one of the first to third embodiments of the present invention is connected in series to a battery circuit in a space formed between the battery packs, and the reset button 2 of the thermal protector 19 is operated from outside the battery pack. It is provided to be able to. A through hole 21 is formed in a part of the case 20 of the battery pack, and the reset button 2 is disposed in the through hole 21.

According to the fifth embodiment, when an abnormality such as a secondary short circuit occurs in the battery pack, the contact between the fixed electrode and the movable electrode in the mounted thermal protector 19 is separated, and the circuit is cut off. can do. After confirming that the abnormal state has been removed, the reset button 2 protruding from the through hole 21 is pushed back to bring the contact between the fixed electrode and the movable electrode into a contact state, whereby the contact is closed again and power is supplied.

The tip of the reset button 2 may be always located inside the outer surface of the battery pack as shown in FIG. 6 when the contact between the fixed electrode and the movable electrode in the thermal protector 19 is in contact. .

As shown in FIG. 7, the battery pack according to the sixth embodiment of the present invention has the same configuration as the battery pack shown in FIG. 6, but differs from the battery pack shown in FIG. The protrusion 22 is formed on a part of the outer surface of the container 1 on the side from which the reset button 2 of the thermal protector 19 extends, and the recess 23 is formed on the case 20 side of the battery pack.

According to the sixth embodiment, the protrusion 22
The thermal protector 19 is fitted by fitting the
Can be easily attached to and held in the case 20 of the battery pack.

As shown in FIG. 8, the battery pack according to the seventh embodiment of the present invention has the same configuration as the battery pack shown in FIG. 6, but differs from FIG. 21
And an elastic cap 24 made of rubber or the like which is capable of operating the reset button 2.

According to the seventh embodiment, the manual reset operation by the reset button 2 is not hindered.
This has the effect of protecting the battery pack from moisture, dust, etc., which may enter through the through-holes 21 during operation and adversely affect the secondary battery and the thermal protector 19 in the battery pack.

Although the cap 24 is attached from the inside of the case 20, there is no problem if it is attached to the outer surface of the case 20.

[0051]

As described above, according to the present invention, it is possible to obtain a highly safe thermal protector which is operated once by an operator after being operated by an overcurrent and has high safety. When used in a battery pack such as a tool, there is an excellent effect that power supply can be manually restarted when an abnormality such as a secondary short circuit of a secondary battery occurs.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thermal protector according to a first embodiment of the present invention, in which a fixed electrode and a movable electrode are in contact with each other.

FIG. 2 is a cross-sectional view in which a fixed electrode and a movable electrode are separated from each other.

FIG. 3 is an enlarged sectional view of a main part of a thermal protector according to a second embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a main part of a thermal protector according to a third embodiment of the present invention.

FIG. 5 is an enlarged perspective view of a main part of a thermal protector according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a battery pack according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view of a main part of a battery pack according to a sixth embodiment of the present invention.

FIG. 8 is a sectional view of a main part of a battery pack according to a seventh embodiment of the present invention.

FIG. 9 is a sectional view of a conventional thermal protector.

[Description of Signs] 1 Container 2 Reset button 3 Resin block 4 Plunger 5 Metal plate 6 First coil spring 7 Second coil spring 8 Plate spring 9 Thermal response element 10 Locking portion 11 Locked portions 12a, 12b Movable electrodes 13a, 13b Fixed electrode 14 Support 15 Filler 16 Metal body 17 Convex part 18 Battery 19 Thermal protector 20 Battery pack case 21 Through hole 22 Convex part 23 Concave part 24 Cap

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01M 10/48 301 H01M 10/48 301 10/50 10/50 F term (Reference) 5G041 AA09 BB11 DA02 DB01 DC09 5H020 AA01 AS06 CC06 CC13 EE01 EE06 KK00 5H030 AA03 AA04 AA06 AS12 FF21 FF26 5H031 CC05 EE01 EE04 KK00

Claims (12)

[Claims] 1. A fixed electrode, a movable electrode, a plunger for bringing the movable electrode into and out of contact with the fixed electrode, and a plunger arranged in an axial direction of the plunger in a container having a locked portion on an inner surface. An elastic body, an elastic plate supported by the plunger and having an engaging portion at one end that is engaged with the locked portion of the container, and a bent inversion operation from the locked portion of the container. A thermal responsive element for detaching the locking portion of the elastic plate, and as the locking portion of the elastic plate separates from the locked portion of the container, the plunger is caused to extend in the axial direction by the extension action of the elastic body. A thermal protector wherein the contact state between the fixed electrode and the movable electrode is released to separate the fixed electrode and the movable electrode, and the separated state is maintained. . 2. The elastic body and the fixed electrode include first and second coil springs and first and second fixed electrodes, respectively, and the first and second fixed electrodes are fixed distances in a support. And the first coil spring is embedded in the support between the first and second fixed electrodes, and the movable electrode comprises first and second movable electrodes, each having a fixed distance. In the conductive plate,
The first and second fixed electrodes and the first and second movable electrodes each take the form of a double-break type contact that is opposed to each other in pairs, and the second coil spring is formed of the conductive material. 2. The thermal protector according to claim 1, wherein the thermal protector is arranged in series with the first coil spring via a plate, and is supported at one end of the plunger. 3. 3. The plunger is fixed to a block having a convex portion, and the convex portion is led out of the container to return a separated state between the fixed electrode and the movable electrode to a contact state. 3. The thermal protector according to claim 1, wherein the thermal protector is a reset button. 4. The elastic plate according to claim 1, wherein the other end of the elastic plate on which the locking portion is not formed is supported in contact with a part of the block. Thermal protector. 5. The thermal protector according to claim 1, wherein the thermally responsive element is provided near a contact between the fixed electrode and the movable electrode. 6. The thermal protector according to claim 1, wherein an end of the locking portion of the elastic plate has a curved shape. 7. The locking portion of the elastic plate and the locked portion of the container are made of resin or metal.
7. The thermal protector according to any one of items 6 to 6. 8. The thermal protector according to claim 1, wherein a concave portion or a convex portion is formed on a part of an outer surface of the container from which the reset button is led out. 9. The thermal protector according to claim 1, wherein the thermal protector is connected in series to a battery circuit in a battery pack containing a plurality of secondary batteries, and the reset button of the thermal protector is connected to the thermal protector. A battery pack characterized by being disposed in a through hole formed in a part of a battery pack. 10. A concave or convex portion is formed on an inner surface of a battery pack, and the concave or convex portion is fitted with a concave or convex portion formed in a container of the thermal protector according to claim 8, so that the thermal protector is formed. The battery pack according to claim 9, wherein the battery pack is held in the battery pack. 11. The device according to claim 9, wherein when the fixed electrode and the movable electrode are in contact with each other, the tip of the reset button is located inside the outer surface of the battery pack. 11. The battery pack according to 10. 12. The battery pack according to claim 9, further comprising a cap attached to the through hole and operable to operate the reset button.