JP2002324467A - Thermal protector and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal protector ultra thin shape, low contact resistance and low cost which is sufficiently adaptable to a lithium-ion battery pack by realizing a simple element composition of ultra-thin shape with a thickness dimension for an outer vessel of 1.0 mm or below, and a simple manufacturing process adapted to it, using a thermal element body made of a bimetal for temperature detection. SOLUTION: This thermal protector is equipped with a pair of two fixed electrodes 2 and 3, a movable electrode 4 including a thermal clement body, without being fastened to other members, arranged adjacent to the fixed electrodes, and an outer vessel 5 accommodating combination of the fixed electrodes and the movable electrode. The movable electrode approaches to/ moves away from the two fixed electrodes by thermal deformation of thermal element body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an element configuration of a thermal protector having an ultra-thin shape, such as an overheat protection element, particularly for a battery pack, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A thermal protector is provided in an electric device or a heat source application device, and has a function of detecting overheating or overcurrent at the time of abnormality of the device and temporarily interrupting a circuit current. This is an overheat protection element that reports an abnormal state. There are various types of thermal protectors having different configurations, shapes and dimensions, and operating characteristics according to the equipment used. Specifically, the varieties conventionally used for copper-iron ballasts and electronic inverter circuits for motors and fluorescent lamps are, so to speak, technically completed configurations and relatively large, for example, thickness t Is 3.1mm or 3.6mm
Is a product having an outer container shape. On the other hand, with the recent information society, a new type of thermal protector is being developed and deployed, particularly for battery packs of portable electric devices, for which demand is growing rapidly.

The first requirement for a thermal protector for a battery pack is to make the outer container smaller, especially thinner. This is a prerequisite for adapting the battery pack to a small size for portable use. The configuration of such a small-sized thermal protector according to the related art is disclosed in, for example, Japanese Patent No. 2636615.

FIG. 8 shows a typical configuration of such a thermal protector disclosed in the above publication. First, the thermal protector 21 is constituted by assembling a pair of fixed electrode members 22 and a movable electrode member 23 which comes into contact with and separates from the fixed electrode members 22, and this is accommodated in an outer container 24 made of PBT resin or the like. The fixed electrode body 22 has a fixed contact 2 at one end.
And a fixed electrode side lead wire 28 welded and connected to the other end of the contact plate 26 via a fixed electrode plate 27.
Consists of The movable electrode body 23 includes a thermally responsive element body 30 made of a bimetal or a trimetal to which a hemispherical movable contact 29 is welded at one end, and a movable electrode plate 31 at the other end.
And a movable electrode-side lead wire 32 which is welded and connected via a wire. The fixed contact 25 and the movable contact 29 are generally made of silver or a silver alloy material. A mount body 34 in which the fixed electrode body 22 and the movable electrode body 23 are assembled by the resin beads 33 is fixed in the outer container 24 by the resin filler 35.
It is installed. The inside of the outer container 24 is filled with air at atmospheric pressure.

[0005] In the configuration of the thermal protector 21, the thermally responsive element body 30 of the movable electrode body 23 has a basic function of detecting a temperature rise due to overheating and overcurrent at the time of equipment abnormality. Here, the thermally responsive element body 30 is used to instantaneously and reliably perform the opening and closing operation of the movable contact 29 in order to prevent an arcing phenomenon occurring between the contact with the fixed contact 25 during the opening and closing operation of the movable contact 29. Special punching processing is performed so as to have a snap operation mechanism.
This is one characteristic of the structure of the thermal protector. In addition, the movable electrode body 23 including such a thermally responsive element 30 according to the related art is installed in a form in which an end other than the movable contact side is fixed.

As described above, the thermal protector according to the prior art basically comprises (I) a movable electrode body comprising a thermally responsive element body having a movable contact at one end and a fixed electrode body comprising a fixed contact. (II) At least the movable electrode body has a structure in which the movable electrode body is assembled / installed in the outer container in a form in which an end other than the movable contact side is fixed. ing.

In the manufacturing process of the thermal protector 21, (I) each part of the fixed electrode body 22 and the movable electrode body 23 is processed and manufactured, and (II) each of the above parts is welded and connected to the fixed electrode body. 22 and the movable electrode body 23 are manufactured, and (III) a mount body 34 in which the fixed electrode body 22 and the movable electrode body 23 are assembled with the resin beads 33 is manufactured.
(IV) The mount body 34 is mounted on the outer container 24 using a resin filler 35 by a so-called potting method.

A feature of the thermal protector 21 is that the outer container 24 has a thickness t2.4 mm, a thin shape, and a mountain-shaped cross-sectional shape. As a result, as shown in FIG. 9, the thermal protector 21 is particularly suitable for the conventional mainstream, such as nickel-cadmium and nickel-hydrogen.
It can be well adapted to the equipment of the battery pack 36 and has been widely used. Further, another key feature is that the contact resistance of the thermal protector is 10%.
This is extremely low at mΩ or less. As a result, a so-called low impedance battery pack is realized in which the contact resistance loss of the thermal protector connected in series to the battery is low, and the effect of using the battery pack becomes longer is obtained.

[0009]

In recent years, new high-capacity lithium-ion batteries have been developed and spread in place of conventional nickel-cadmium and nickel-metal hydride batteries. This battery has a rectangular shape, and the protection element is attached to a side wall surface of the battery, so that the protection element is required to be thinner than a conventional battery thermal protector. On the other hand, as a recent overcurrent / overheat protection element, a so-called PT, which is a positive temperature characteristic resistance element made of a conductive resin material, is used.
C thermistor was developed and commercialized. The PTC thermistor has an extremely simple element configuration, has an ultrathin shape with a plate-shaped thickness t of 0.8 mm or less, and has a feature of a simple manufacturing process and low cost. As a result, it has been used as a main protection element for a new lithium ion battery pack instead of a conventional thermal protector. By the way, it has been pointed out from the beginning that the internal resistance of a PTC thermistor as a protection element is higher than the contact resistance of a thermal protector of 10 mΩ or less. That is, the internal resistance of the PTC thermistor is already as high as several tens of mΩ as an initial value in a room temperature state before the operation, and further increases as the temperature increases for each operation. Therefore, since the resistance loss in the PTC thermistor increases accordingly, a low-impedance battery pack when a conventional thermal protector is provided cannot be obtained, and it is inevitable that the use time becomes shorter. In addition, especially in the pulse operation accompanying the recent digitization of electric devices, the use of peak currents of battery packs has increased and the resistance loss of PTC thermistors has further increased. Have been.

[0010] As one of the measures described above, there is a demand for the redevelopment of a thermal protector which basically has a characteristic of extremely low contact resistance. As described above, the conventional thermal protector for a battery pack is smaller than the original model for motors and electronic circuits, but it must be further downsized, especially thinner, to be suitable for new lithium battery packs. Shaping is the first issue. A specific technical problem is that according to market research results by the present inventor, the thickness t of the outer container of the thermal protector achieves a level of 1.0 mm or less. This makes it possible to adapt to the equipment for the lithium battery pack. Further, another object is to reduce the cost by realizing a simpler element configuration and manufacturing process as compared with a conventional thermal protector.

According to the present invention, there is provided a thermal protector using a thermally responsive element made of bimetal or trimetal for temperature detection, wherein the outer container has a thickness t of 1.0.
Ultra-thin, low-cost thermal element that realizes a simple element configuration with an ultra-thin shape of less than 1 mm or less, and at the same time realizes a simple manufacturing process adapted to this. The purpose is to provide a protector.

[0012]

According to a first aspect of the present invention, there is provided a thermal protector having a thermally responsive element body for detecting a temperature. One fixed electrode body, a movable electrode body disposed adjacent to the fixed electrode body without being fixed to other members including the thermally responsive element body, and the fixed electrode body and the movable electrode body are combined and housed. And an outer container. The movable electrode body comes into contact with and separates from the two fixed electrode bodies due to the thermally responsive deformation of the thermally responsive element body.

As a result, a simple structure having an ultra-thin shape can be obtained, a simple manufacturing process suitable for this structure can be realized, and the device can be sufficiently adapted to a new lithium ion battery pack.

Preferably, in the above basic structure, the outer container includes a resin base on which two fixed electrode bodies are insert-molded, and a resin cover mounted on the resin base as an upper lid. The fixed contact formed on each of the two fixed electrode bodies is exposed from the resin base, and the movable contact portion formed on the movable electrode body comes into contact with and separates from the fixed contact.

As a result, the structure of the ultra-thin element can be further simplified, and the manufacturing process can be further simplified by reducing the number of manufacturing steps, thereby achieving further cost reduction.

In any one of the above configurations,
As described in above, it is possible to adopt a configuration in which separate contact members are not attached to both the fixed electrode body and the movable electrode body.

As a result, the thickness of the outer container is reduced by the thickness of the unmounted contact member, and the thickness t of the container is reduced to 1.0 m.
m, and the element configuration is further simplified, the number of members and related manufacturing steps are reduced, and the cost can be further reduced.

Preferably, in any one of the above structures, the two fixed electrode members are each formed with a semi-circular fixed contact, and the movable electrode member has a disk shape. An arcuate movable contact portion which comes into contact with and separates from the two fixed contacts is formed along the outer periphery.

As a result, even if individual contact members are not mounted, a wider contact area is ensured by multipoint contact, and a low contact resistance unique to a thermal protector can be achieved. Therefore, an ultra-thin and low-cost thermal protector having a low contact resistance, which can be adapted to a new lithium ion battery pack, can be obtained.

Preferably, in any one of the above structures, the movable electrode body has a disk shape and is mounted on the outer container while being pressed by the inner portion of the resin cover. And More preferably, in this configuration, the movable electrode body is mounted on the outer container in a state where the movable electrode body is pressed by a protrusion formed inside the resin cover.

Thus, the arc-shaped movable contact portion of the movable electrode body is brought into pressure contact with the semi-circular fixed contact of the two fixed electrode bodies, and a low contact resistance value of 10 mΩ or less unique to the thermal protector is ensured. can get. Therefore, an ultra-thin and low-cost thermal protector having a low contact resistance suitable for a new lithium ion battery pack can be realized.

Preferably, in any one of the above structures, a noble metal thin film is formed on the surfaces of the fixed contact of the fixed electrode and the movable contact of the movable electrode.

As a result, even if individual contact members are not mounted, even if the contact is opened and closed more than 5,000 times, problems such as contact welding do not occur, excellent life characteristics can be achieved, and high quality and ultra thinness can be achieved. A low-cost thermal protector with a shape can be obtained.

In any one of the above structures, preferably, at least one of the resin base and the resin cover has a thin cylindrical space for accommodating a disk-shaped movable electrode body. Are formed along the outer periphery of the disk of the movable electrode body.

As a result, the movement of the movable electrode body is regulated, and a reliable contact opening / closing operation can be guaranteed. Thus, a high-quality, ultra-thin, and low-cost thermal protector can be obtained.

Preferably, in any one of the above structures, a circular portion at the center of the disk-shaped movable electrode body is punched, and the resin base of the outer container or the resin cover is formed. A fine rod is formed in any of them, and the fine rod is inserted into a circular portion of the movable electrode body.

Thus, the movement of the movable electrode body, particularly in the horizontal direction, at the time of opening and closing operation is restricted, and the movement in the vertical direction along the fine rod is mainly performed, so that a more reliable contact opening and closing operation is guaranteed. . At the same time, in the element manufacturing, the permissible range of the processing dimensions of the movable electrode body and the like is expanded, and the cost reduction can be achieved by reducing the cost of parts and improving the manufacturing yield. A costly thermal protector is obtained.

Preferably, in the configuration corresponding to the eighth aspect, at least one of the resin base and the resin cover of the outer container is provided with a guide groove or a guide protrusion along the cylindrical space. Are formed, and a guide piece or a guide piece that fits into a guide groove or a guide protrusion is formed on the outer periphery of the movable electrode body.

Thus, the movement of the movable electrode body in the horizontal and rotational directions at the time of opening and closing operation is restricted, and the movement in the vertical direction along the guide groove or guide projection is mainly performed, so that more reliable contact opening and closing can be performed. Operation can be guaranteed, and a high-quality, ultra-thin and low-cost thermal protector can be obtained.

The method for manufacturing a thermal protector according to the present invention is a method for manufacturing a thermal protector having the above-mentioned basic structure, wherein a resin base on which two fixed electrode bodies are insert-molded is first used. Made,
Next, after the movable electrode body is accommodated in the resin base in a state where it is not fixed to other elements, a resin cover is attached.

According to this method, the manufacturing process is simplified as compared with the prior art, the manufacturing cost can be greatly reduced, and an ultra-thin and low-cost thermal protector can be obtained.

Applied equipment provided with the thermal protector of any of the above structures, particularly a battery pack of lithium ion or the like can be constructed.

As a result, an applied device such as a small, low-impedance battery pack for portable use can be obtained.

[0034]

(Embodiment 1) FIGS. 1 to 4
1 shows an element configuration of the thermal protector according to Embodiment 1 of the present invention. The basic structure of this thermal protector 1 is that three parts, a pair of fixed electrode bodies 2 and 3 and a movable electrode body 4 composed of a free heat-responsive element itself coming and going, are made of a hardly soluble PBT. It is housed in an outer container 5 made of resin. Here, free means that it is not fixed to another member.

FIGS. 1 and 2 show a fixed electrode body 2,
FIG. 3 is a plan cross-sectional view of the thermal protector 1 when 3 is in a conductive state, and a front cross-sectional view of a central portion. FIG. 1 shows a state in which the upper part of the outer container 5 has been removed. Fixed electrode body 2, 3
Are copper-nickel plates (plate thickness t
0.2 mm), and the semicircular fixed contacts 6 and 7 (external diameter φ3.2 mm, internal diameter φ2.2 mm of the semicircular arc) exposed inside the outer container 5 are drawn out of the outer container 5. It comprises external lead plates 8 and 9 and plate portions 10 and 11 embedded in the resin of the outer container 5. Here, on the exposed surfaces of the fixed contacts 6 and 7, a silver or gold thin film is formed by plating or cladding. Further, an insulating gap g0.3 mm is provided between the fixed electrode bodies 2 and 3. In order to firmly fix the fixed electrode bodies 2, 3 in the resin of the outer container 5, the embedded plate parts 10, 11
Are provided with circular punching portions 12 and 13.
The movable electrode body 4 is made of a material of Fe—Ni—Mn / Ni / Fe
-Disc-shaped trimetal plate consisting of three layers of Ni (diameter φ
It is made of a thermally responsive element body having a thickness of 3.0 mm and a thickness of 0.088 mm), and is formed by punching so as to perform a snapping operation, and has a convex shape in which a central portion bulges upward. At its outer periphery, an arc-shaped movable contact portion 14 that comes into contact with and separates from the fixed contacts 6 and 7 of the fixed electrode bodies 2 and 3 is formed. On the surface of the movable contact portion 14, a silver or gold thin film is formed by plating or cladding. The movable electrode body 4 is mounted in the outer container 5 in a so-called free state without fixing any part.

The outer container 5 includes a resin base 15 in which the fixed electrode bodies 2 and 3 are formed by insert molding, and a resin base 1.
5 comprises a resin cover 16 mounted as an upper lid. The shapes of the resin base 15 and the resin cover 16 are as follows.
Both are square (one side L = 3.8 mm). Outer container 5
Is filled with air at atmospheric pressure. A thin cylindrical space 17 (diameter φ3.35 mm, height 0.35 mm) for accommodating the movable electrode body 4 is provided in the resin base 15.
The movable electrode body 4 is formed along the outer periphery of the disk. A cylindrical projection 19 (diameter φ0.6 mm, thickness t0.1 mm) is provided at the center of the resin bottom surface 18 of the resin base 15. The thickness t of the resin bottom surface 18 excluding the cylindrical protrusion 19 is set to 0.45 mm. On the other hand, a cylindrical projection 20 (diameter φ0.6 m) for pressing the center of the free movable electrode body 4 is also provided at the center of the resin cover 16.
m, thickness t0.17 mm). Further, the thickness t of the resin cover 16 is 0.2
mm. As shown in FIG. 3, the resin base 15 and the resin cover 1 are formed such that a cylindrical space 17 for accommodating the movable electrode body 4 is formed toward the resin cover 16.
6 may be changed together.

The operation of the above-described thermal protector 1 is shown in FIG. When the temperature of the movable electrode body 4 composed of the thermally responsive element body rises from a so-called inversion temperature value defined in a range of 70 to 80 ° C. due to overheating of the applied device incorporating the thermal protector 1 at the time of abnormality, the movable electrode body The body 4 reverses to a concave shape that swells downward. Thereby,
The arcuate movable contact portion 14 is separated from the fixed contacts 6 and 7, and the conduction between the fixed electrode bodies 2 and 3 is cut off. In this case, the central part of the movable electrode body 4 is pressed by the cylindrical projection 19 of the resin base 15, whereby the movement of the movable electrode body 4 is suppressed, and the movable contact part 14 is securely separated from the fixed contacts 6, 7. It is. The temperature of the movable electrode body 4 is 40 to 50 ° C.
When the temperature is lower than the so-called return temperature value defined in the range, the movable electrode body 4 returns to the original shape in FIG. 2, and the movable contact part 14 comes into pressure contact with the fixed contacts 6 and 7 to fix the fixed electrode body. The continuity between the two and three is restored.

The thermal protector 1 according to the present embodiment
The basic feature of the present invention is that instead of the combination of a pair of fixed electrode bodies and a movable electrode body fixed at one end using a thermally responsive element body according to the prior art, two fixed electrode bodies forming a pair and a free thermally responsive element body are used. This is the introduction of a new combination of movable electrode bodies. As a result, an ultra-thin and low-cost thermal protector having a simple element configuration, which is a basic object, is realized.

The first feature of the structure of the thermal protector 1 is that the outer container 5 includes a resin base 15 on which two fixed electrode bodies 2 and 3 are insert-molded, and a resin cover mounted on the resin base 15 as an upper lid. The fixed contacts 6 and 7 formed on each of the two fixed electrode bodies 2 and 3 are exposed from the resin base 15, while the movable contact portion 14 formed on the free movable electrode body 4 is That is, it is configured to be brought into contact with and separated from the two fixed contacts 6 and 7. As a result, the element configuration having an ultra-thin shape is simplified, and the manufacturing process is further simplified by reducing the number of manufacturing steps. The second feature is that none of the fixed electrode members 2 and 3 and the movable electrode member 4 is provided with a conventional contact member such as silver. As a result, the thickness of the outer container 5 is reduced by the thickness of the contact member, an ultra-thin shape with a container thickness t of 1.0 mm or less is realized, and the element configuration is further simplified, and such members are also added. Further cost reduction was achieved by reducing the number of related man-hours. The third feature is that semi-circular fixed contacts 6 and 7 are formed on the fixed electrode bodies 2 and 3, while a movable contact part 14 having an arc shape which comes into contact with and separates from the fixed contacts 6 and 7 has a convex disk-shaped movable electrode. That is, it is formed along the outer periphery of the body 4. As a result, even if individual contact members were not mounted, a wider contact area was ensured, and this was combined with the pressurized contact described later to obtain a low contact resistance of 10 mΩ or less specific to a thermal protector. A fourth feature is that the movable electrode body 4 is pressed by the cylindrical projection 20 formed at the center of the resin cover 16. Thus, the arc-shaped movable contact portion 14 of the movable electrode body 4 is brought into pressure contact with the fixed contacts 6 and 7 of the fixed electrode bodies 2 and 3. By the combination of the pressure contact and the above-mentioned large contact area, a low contact resistance value of 10 mΩ or less unique to the thermal protector was obtained. The fifth feature is that the fixed contacts 6 of the fixed electrode bodies 2 and 3
7 and a noble metal thin film such as silver or gold is formed on the surface of the movable contact portion 14 of the movable electrode body 4. As a result, even if individual contact members were not mounted, the thermal protector 1 was able to obtain excellent life characteristics and high quality characteristics without causing problems such as contact welding even in 5000 times of contact opening and closing operations. The sixth feature is the resin base 1
5 is that a thin cylindrical space 17 for accommodating the free disk-shaped movable electrode body 4 is formed along the outer periphery of the disk of the movable electrode body 4. As a result, the free movement of the movable electrode body 4 is regulated, the reliable contact opening / closing operation is guaranteed, and high-quality operating characteristics of the element are obtained.

Further, the feature of the manufacturing process of the thermal protector 1 is that the manufacturing process is simplified as compared with the prior art, by making the most of the feature in the above-described configuration. As a result, a significant reduction in manufacturing cost was realized. Actually, the thermal protector 1 manufactures (I) a pair of fixed electrodes 2 and 3 and a movable electrode 4 by punching and molding, and (II) insert-molds the pair of fixed electrodes 2 and 3 to form a resin. The base 15 is manufactured, and (III) the movable electrode body 4 is simply accommodated in the resin base 15, and finally the resin cover 16 is attached to the resin base 15 by any method such as a resin adhesive, heat welding, or ultrasonic welding. It is manufactured by an extremely simple manufacturing process of mounting.

The thermal protector 1 manufactured according to the element configuration and the manufacturing process shown in the first embodiment has a target size of 3.8 mm square of the outer container 5 and a thickness t of 1.0 mm. A thin profile has been achieved. In addition, it was found that the total cost including the manufacturing cost estimated by the present inventor can be greatly reduced to 40% as compared with the conventional thermal protector of FIG. On the other hand, in the element characteristics, as the contact resistance in the closed state of the fixed contacts 6 and 7 and the movable contact portion 14, a value in the range of 7 to 9 mΩ was obtained, and the characteristic of the low contact resistance unique to the thermal protector was maintained. As a result, a reliable contact opening / closing operation was assured, and excellent life characteristics that could withstand 5,000 or more contact opening / closing operations were obtained.

(Embodiment 2) FIGS. 5 and 6 are a plan sectional view and a central sectional view, respectively, showing an element configuration of a thermal protector 101 according to Embodiment 2 of the present invention. The planar element configuration of the thermal protector 101 shown in FIG. 5 is almost the same as the thermal protector 1 shown in FIG. 5 and 6
, The elements corresponding to the elements in FIG. 1 will be described with reference numbers having the same last two digits of the reference numbers. The only difference from the first embodiment is that a circular portion 121 (diameter φ0.6 mm) is punched in the center of the movable electrode body 104 made of a free thermoresponsive element body, while the resin base of the outer container 105 is formed. A fine rod 122 (diameter φ 0.5 mm) is formed on the cylindrical projection 119 of 115, and the fine rod 122 is inserted into the circular portion 121 of the movable electrode body 104. This is a new feature of the thermal protector 101 according to the second embodiment provided in terms of the element configuration. As shown in FIG. 6, the resin cover 116 is attached to the resin base 115 such that the distal end of the fine rod 122 of the resin base 115 also penetrates the center of the resin cover 116. The fine rod 122 may be formed not on the resin base 115 but on the cylindrical protrusion 120 of the resin cover 116.

The manufacturing process of the thermal protector 101 of FIG. 5 is almost the same as that of the thermal protector 1 of FIG.
It is very simple. The only difference is that, as shown in FIG. 6, in the final step in which the resin cover 116 is mounted on the resin base 115 by the thermal welding method, the resin cover 1
The fine rod 122 provided at the center of the core 16 and inserted into the through hole 123 is also thermally welded to the resin cover 116 at the same time.

Due to the new feature of the thermal protector 101, the free operation of the movable electrode body 104 at the time of opening / closing operation or the like is restricted particularly in the horizontal direction.
The movement in the vertical direction along the fine rod 122 is mainly performed,
A more reliable contact opening and closing operation was guaranteed. Further, in the actual manufacture of the element, the movable electrode body 104 and the resin base 115
The allowable range of the processing dimensions of the cylindrical space 117 and the like can be widened, and the cost can be further reduced by reducing the cost of parts and improving the production yield. In addition,
In the thermal protector 101, a small and ultra-thin shape, low contact resistance, and excellent life characteristics similar to the thermal protector 1 of the first embodiment were realized.

(Embodiment 3) FIGS. 7A and 7B are plan sectional views showing the element configurations of two types of thermal protectors 201 according to Embodiment 3 of the present invention. The element configuration of the thermal protector 201 shown in FIGS. 7A and 7B is almost the same as that of the thermal protector 1 according to the first embodiment shown in FIG. FIG.
Regarding each element in (a) and (b), the elements corresponding to the elements in FIG. 1 will be described with reference numbers having the same last two digits of the reference numbers. The only difference from the first embodiment is that, in order to restrict both the horizontal and rotational movements of the free movable electrode body 204, for example, FIG.
In the type of (a), the cylindrical space 2 of the resin base 215 is used.
17, guide grooves 221 and 222 are provided, and guide pieces 223 and 224 that fit into the guide grooves 221 and 222 are provided on the outer periphery of the movable electrode body 204. For the same purpose, in the type of FIG.
Guide protrusions 225, 226 along the cylindrical space 217 of
Are provided on the outer periphery of the movable electrode body 204.
5 and 226 are provided with guide pieces 227 and 228 to be fitted. These are new features of the thermal protector 201 according to the third embodiment. The manufacturing process of the thermal protector 201 is exactly the same as that of the thermal protector 1 shown in FIG.

Due to the new feature of the thermal protector 201, the movement of the free movable electrode body 204 at the time of opening / closing operation or the like is restricted both in the horizontal and rotational directions, so that the guide grooves 221 and 222 or the guide protrusion 225 are provided. , 226 in the vertical direction. Thereby, as in the case of the thermal protector 101 according to the second embodiment, a more reliable contact opening / closing operation is guaranteed. In the thermal protector 201, the same small and ultra-thin shape and low cost as in the thermal protector 1 according to the first embodiment, and the same low contact resistance and excellent life characteristics were realized.

As described above, by providing the element configuration shown in each of the above-described embodiments and manufacturing it in the above-described manufacturing process, the outer container has a small and ultra-thin shape having a thickness t of 1.0 mm or less. In addition, a low contact resistance of 10 mΩ or less unique to the thermal protector and excellent life characteristics are achieved, and the intended thermal protector can be obtained.

[0048]

According to the present invention, in a thermal protector using a thermally responsive element made of bimetal or trimetal for temperature detection, the thickness t of the outer container is increased.
Is an ultra-thin simple element configuration of 1.0 mm or less;
A simple manufacturing process adapted to this can be realized. At the same time, a low contact resistance of 10 mΩ or less and excellent life characteristics unique to the thermal protector are achieved. As a result, an ultra-thin and low-cost thermal protector that can be sufficiently applied to a new lithium ion battery pack can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a thermal protector in a closed state according to Embodiment 1 of the present invention.

2 is a front sectional view of a central portion of the thermal protector in FIG. 1 in a closed state.

FIG. 3 is a front sectional view of a thermal protector showing a modification of the embodiment shown in FIG. 2;

4 is a front sectional view of a central portion of the thermal protector of FIG. 1 in an open state.

FIG. 5 is a cross-sectional plan view of the thermal protector according to Embodiment 2 of the present invention in a closed state.

6 is a front sectional view of a central portion of the thermal protector in FIG. 5 in a closed state.

FIG. 7 is a cross-sectional plan view of the thermal protector according to Embodiment 3 of the present invention in a closed state.

FIG. 8 is a diagram showing an element configuration of a thermal protector in a conventional example.

FIG. 9 is a configuration diagram of a conventional example in which a thermal protector is attached to a battery pack.

[Explanation of symbols]

1, 101, 201 Thermal protector 2, 3, 102, 103, 202, 203 Fixed electrode body 4, 104, 204 Movable electrode body 5, 105, 205 Outer container 6, 7, 106, 107, 206, 207 Fixed contact 8 , 9, 108, 109, 208, 209 External lead plate 10, 11, 110, 111, 210, 211 Embedded plate portion 12, 13, 112, 113, 212, 213 Punching portion 14, 114, 214 Movable contact portion 15, 115, 215 Resin base 16, 116 Resin cover 17, 117, 217 Cylindrical space 18, 118 Resin bottom 19 Cylindrical projection 20 Cylindrical projection 121 Circular portion 122 Fine rod 221, 222 Guide groove 223, 224 Guide pieces 225, 226 Guide protrusions 227, 228 Guide pieces

Claims (13)

[Claims] 1. A thermal protector having a thermally responsive element body for detecting temperature, comprising: a pair of fixed electrode bodies; and a fixed electrode including the thermally responsive element body and not being fixed to another member. A movable electrode body disposed adjacent to the body, and an outer container in which the fixed electrode body and the movable electrode body are combined and housed, wherein the movable electrode body is thermally responsive to the thermally responsive element body. A thermal protector which comes into contact with and separates from the two fixed electrode bodies by deformation. 2. The outer container includes a resin base on which the two fixed electrode bodies are insert-molded, and a resin cover mounted on the resin base as an upper lid, and is formed on each of the two fixed electrode bodies. The thermal protector according to claim 1, wherein the fixed contact is exposed from the resin base, and a movable contact portion formed on the movable electrode body contacts and separates from the fixed contact. 3. The thermal protector according to claim 1, wherein a separate contact member is not mounted on any of the two fixed electrode bodies and the movable electrode body. 4. A fixed contact having a semicircular arc shape is formed on each of the two fixed electrode bodies, and the movable electrode body has a disk shape, and comes into contact with and separates from the two fixed contacts along its outer periphery. The thermal protector according to any one of claims 1 to 3, wherein an arc-shaped movable contact portion is formed. 5. The movable electrode body according to claim 2, wherein the movable electrode body has a disk shape and is mounted on the outer container in a state where the movable electrode body is pressed by an inner portion of the resin cover. Thermal protector. 6. The thermal protector according to claim 5, wherein the movable electrode body is provided on the outer container in a state where the movable electrode body is pressed by a protrusion formed inside the resin cover. 7. The thermal protector according to claim 2, wherein a noble metal thin film is formed on surfaces of a fixed contact of the fixed electrode body and a movable contact portion of the movable electrode body. 8. A thin cylindrical space for accommodating the disk-shaped movable electrode body is formed along at least one of the resin base and the resin cover along the outer periphery of the disk of the movable electrode body. The thermal protector according to any one of claims 3 to 7, wherein: 9. A circular portion at the center of the disk-shaped movable electrode body is punched, and a fine rod is formed on either a resin base or a resin cover of the outer container, and the fine rod is The thermal protector according to any one of claims 2 to 8, wherein the thermal protector is configured to be inserted into a circular portion of the movable electrode body. 10. A guide groove or guide protrusion is formed along at least one of the resin base and the resin cover of the outer container along the cylindrical space, and the guide groove or guide protrusion is formed on an outer periphery of the movable electrode body. 9. The thermal protector according to claim 8, wherein a guide piece or a guide piece that fits into the guide is formed. 11. A pair of fixed electrode bodies, a movable electrode body including a thermally responsive element body and arranged adjacent to the fixed electrode body without being fixed to another member, and the fixed electrode body And an outer container in which the movable electrode body is combined and accommodated, wherein the outer container is composed of a resin base and a resin cover attached to the resin base, and the movable electrode body is a heat-responsive element body. In the method for manufacturing a thermal protector that comes into contact with and separates from the two fixed electrode bodies by thermally responsive deformation, first, the resin base on which the two fixed electrode bodies are insert-molded is manufactured. A method for manufacturing a thermal protector, wherein the resin cover is attached after the movable electrode body is accommodated in a state where it is not fixed to other elements. 12. An applied device comprising the thermal protector according to claim 1. 13. A battery pack comprising the thermal protector according to claim 1.