Breaker, safety circuit and secondary battery pack

Abstract

To provide a breaker capable of suppressing generation of cutting powder when welding a case.SOLUTION: A breaker 1 includes a movable piece 4 that includes a fixed contact 21, an elastic portion 44 that is elastically deformable, and a movable contact 41 at one end of the elastic portion 44, and presses the movable contact 41 against the fixed contact 21 to make contact with the fixed contact 21, a thermally responsive element 5 that changes the movable piece 4 from a conducting state in which the movable contact 41 is in contact with the fixed contact 21 to an interrupted state in which the movable contact 41 is separated from the fixed contact 21 by deforming with a change in a temperature, a case body 7 having a housing recess 73 for housing the fixed contact 21, the movable piece 4 and the thermally responsive element 5, and a lid member 8 fixed to the case body 7 and covering the housing recess 73. The lid member 8 includes an embedded portion in which a part of the movable piece 4 is embedded, and a first recess that is depressed in a thickness direction of the lid member 8. The case body 7 includes a first protrusion that is fitted into the first recess.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a small breaker or the like to be built into an electrical device or the like. [Background technology]

[0002] BACKGROUND ART Conventionally, breakers have been used as protective devices (safety circuits) for secondary batteries, motors, heaters, and the like of various electrical devices (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2011 / 105175 publication Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned Patent Document 1 discloses a breaker in which a case body and a cover member are ultrasonically welded to form a case.

[0005] However, vibrations during welding can cause the movable piece to shift position relative to the recessed housing of the case body, and if the movable piece vibrates while interfering with the case body, the resin of the case body is scraped away by the movable piece, generating cuttings. If the cuttings move and become trapped between the fixed contact and the movable contact, there is a risk of contact failure.

[0006] The present invention has been devised in view of the above circumstances, and has as its main object to provide a breaker that can suppress the generation of cutting powder when the case is welded. [Means for solving the problem]

[0007] The present invention is a breaker comprising: a fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, pressing the movable contact against the fixed contact to bring it into contact; a thermally responsive element that deforms in response to temperature changes, thereby transitioning the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having an accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; and a second resin case fixed to the first resin case and covering the accommodating recess, wherein the second resin case has an embedding portion for embedding a portion of the movable piece and a first recess that is recessed in the thickness direction of the second resin case, and the first resin case has a first convex portion that fits into the first recess.

[0008] In the breaker according to the present invention, it is preferable that the first protrusion includes a first side surface perpendicular to the short-side direction of the movable piece and a second side surface perpendicular to the long-side direction of the movable piece.

[0009] In the breaker of the present invention, it is desirable that the first resin case has a first slope formed on the outside of the movable piece of the first convex portion in the short direction, and the second resin case has a second slope corresponding to the first slope.

[0010] In the breaker according to the present invention, it is preferable that the second slope has a rib formed along an outer edge of the second resin case so as to protrude toward the first resin case.

[0011] In the breaker according to the present invention, it is preferable that the rib is formed continuously from the second slope to the embedded portion.

[0012] In the breaker according to the present invention, it is desirable that the first resin case has a second recess on the side of the fixed contact, and the second resin case has a second protrusion that fits into the second recess.

[0013] In the breaker according to the present invention, it is preferable that the first protrusion is disposed further outward in the longitudinal direction of the movable piece than the accommodating recess.

[0014] In the breaker of the present invention, it is desirable that the second resin case includes a protruding portion that protrudes from the embedded portion toward the movable contact, and the first recess is formed on both sides of the protruding portion in the short direction of the movable piece.

[0015] The present invention is a safety circuit for an electrical device, comprising the above-mentioned breaker.

[0016] The present invention is a secondary battery pack including the above-mentioned breaker. [Effects of the Invention]

[0017] In the breaker of the present invention, a portion of the movable piece is embedded in the second resin case. This allows the movable piece to be fixed in an accurate position relative to the second resin case. The first resin case has a first convex portion that fits into a first concave portion of the second resin case. The fit between the first concave portion and the first convex portion prevents the second resin case from shifting in position relative to the first resin case during welding. Therefore, the movable piece is accurately positioned relative to the first resin case, preventing the movable piece from shifting in position due to vibration during welding and suppressing the generation of cutting powder. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a breaker manufactured according to the present invention in an unassembled state; [Figure 2] 3 is a cross-sectional view showing the breaker in a normal charging or discharging state. FIG. [Figure 3] FIG. 4 is a cross-sectional view showing the breaker in an overcharged state or during an abnormality. [Figure 4] FIG. 10 is a perspective view showing a lid member in which a movable piece and a cover piece are embedded. [Figure 5] FIG. 10 is a perspective view showing a case body in which a fixing piece is embedded. [Figure 6]FIG. 2 is a plan view showing the configuration of a secondary battery pack equipped with the breaker of the present invention. [Figure 7] 1 is a circuit diagram of a safety circuit including the breaker of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] A circuit breaker according to an embodiment of the present invention will be described with reference to the drawings. Figures 1 to 3 show the configuration of a circuit breaker 1 manufactured according to the present invention. The circuit breaker 1 is mounted in an electrical device or the like to protect the electrical device from excessive temperature rise or overcurrent.

[0020] Breaker 1 is composed of a fixed piece 2 having a fixed contact 21, a movable piece 4 having a movable contact 41 at one end, a thermally responsive element 5 that deforms with temperature changes, a PTC (Positive Temperature Coefficient) thermistor 6, and a resin case 10 that houses fixed piece 2, movable piece 4, thermally responsive element 5, and PTC thermistor 6. Resin case 10 is composed of a case body (first resin case) 7, a lid member (second resin case) 8 attached to the top surface of case body 7, and the like.

[0021] The fixed piece 2 is formed, for example, by pressing a metal plate whose main component is copper or the like (other metal plates include copper-titanium alloy, nickel silver, brass, etc.), and is embedded in the case body 7 by insert molding. One end of the fixed piece 2 is formed with a terminal 22 that is electrically connected to an external circuit, and the other end is formed with a support portion 23 that supports the PTC thermistor 6. The terminal 22 protrudes to the outside of the case body 7. The PTC thermistor 6 is placed on and supported by convex protrusions (dowels) 24 formed in three places on the support portion 23 of the fixed piece 2. By bending the fixed piece 2 in a stepped shape, the fixed contacts 21 and the support portion 23 are arranged in a staggered manner, making it easy to ensure space for accommodating the PTC thermistor 6.

[0022] The fixed contact 21 is formed at a position facing the movable contact 41 by cladding, plating, welding, or coating with a highly conductive material such as silver, nickel, nickel-silver alloy, copper-silver alloy, or gold-silver alloy, and is exposed from a part of an opening 73a formed inside the case body 7. The terminal 22 protrudes outward from an edge of the case body 7. The support part 23 is exposed from an opening 73d formed inside the case body 7.

[0023] In this application, unless otherwise specified, the surface of fixed piece 2 on which fixed contact 21 is formed (i.e., the upper surface in FIG. 1) is referred to as the first surface, and the opposite surface is referred to as the second surface. The same applies to other components, such as movable piece 4, thermally responsive element 5, PTC thermistor 6, and resin case 10.

[0024] The movable piece 4 is formed into an arm shape symmetrical about the center line in the longitudinal direction by pressing a plate-shaped metal material whose main component is copper or the like. A part of the movable piece 4 (a fixed part 43 described later) is embedded in the cover member 8 by insert molding.

[0025] A movable contact 41 is formed at one end in the longitudinal direction of the movable piece 4. The movable contact 41 is made of, for example, the same material as the fixed contact 21, and is joined to one end of the movable piece 4 by welding, cladding, crimping, or other techniques.

[0026] A terminal 42 that is electrically connected to an external circuit is formed on the other end of the movable piece 4. The terminal 42 protrudes outward from the edge of the cover member 8. A fixed portion 43 that is embedded and fixed in the cover member 8 is provided between the movable contact 41 and the terminal 42. The fixed portion 43 is arranged on the terminal 42 side.

[0027] The movable piece 4 has an elastic portion 44 between the movable contact 41 and the fixed portion 43. The elastic portion 44 extends from the fixed portion 43 toward the movable contact 41. The movable piece 4 is cantilevered by the cover member 8 at the fixed portion 43 on the base end side of the elastic portion 44, and in this state, the elastic portion 44 elastically deforms toward the first surface, so that the movable contact 41 formed at the tip end of the elastic portion 44 is pressed against the fixed contact 21 and comes into contact with it, allowing electricity to flow between the fixed piece 2 and the movable piece 4.

[0028] It is desirable that the movable piece 4 is curved or bent by press working at the elastic part 44. There are no particular limitations on the degree of curvature or bending as long as it can accommodate the thermally responsive element 5, and it may be set appropriately taking into consideration the elastic force at the operating temperature and the return temperature, the pressing force of the contacts, etc. Also, a pair of protrusions (contact parts) 44a, 44b are formed on the second surface of the elastic part 44 so as to face the thermally responsive element 5. The protrusions 44a, 44b contact the thermally responsive element 5, and deformation of the thermally responsive element 5 is transmitted to the elastic part 44 via the protrusions 44a, 44b (see FIGS. 1, 2 and 3).

[0029] The thermally responsive element 5 is disposed between the movable piece 4 and the PTC thermistor 6. That is, the thermally responsive element 5 is placed on a first surface of the PTC thermistor 6, which will be described later. The thermally responsive element 5 transitions the state of the movable piece 4 from a conductive state in which the movable contact 41 contacts the fixed contact 21 to a cutoff state in which the movable contact 41 is separated from the fixed contact 21. The thermally responsive element 5 is formed into a plate shape by laminating thin plates with different thermal expansion coefficients, and has an initial shape with a curved arc-like cross section. When the reversal operating temperature is reached due to overheating, the curved shape of the thermally responsive element 5 reverses with a snap motion, and returns to its original shape when the temperature drops below the forward rotation return temperature due to cooling. The initial shape of the thermally responsive element 5 can be formed by press working. The material and shape of the thermally responsive element 5 are not particularly limited as long as the elastic portion 44 of the movable piece 4 is pushed up by the reverse warping deformation of the thermally responsive element 5 at the desired temperature and returns to its original shape by the elastic force of the elastic portion 44, but a rectangular shape is desirable from the standpoint of productivity and efficiency of the reverse warping deformation.

[0030] The material for the thermally responsive element 5 is a laminate of two types of materials with different thermal expansion coefficients, such as nickel silver, brass, or stainless steel, which are combined according to the required conditions. For example, a material for the thermally responsive element 5 that can achieve stable reverse operation temperatures and forward rotation return temperatures is preferably a combination of a copper-nickel-manganese alloy on the high expansion side and an iron-nickel alloy on the low expansion side. Furthermore, from the standpoint of chemical stability, a more desirable material is a combination of an iron-nickel-chromium alloy on the high expansion side and an iron-nickel alloy on the low expansion side. Furthermore, from the standpoints of chemical stability and processability, a more desirable material is a combination of an iron-nickel-chromium alloy on the high expansion side and an iron-nickel-cobalt alloy on the low expansion side.

[0031] When the movable piece 4 is in a disconnected state, the PTC thermistor 6 establishes electrical continuity between the fixed piece 2 and the movable piece 4 via the thermally responsive element 5. The PTC thermistor 6 is disposed between the fixed piece 2 and the thermally responsive element 5. In other words, the support portion 23 of the fixed piece 2 is located directly below the thermally responsive element 5, sandwiching the PTC thermistor 6 between them. When the electrical continuity between the fixed piece 2 and the movable piece 4 is interrupted due to reverse warpage of the thermally responsive element 5, the current flowing through the PTC thermistor 6 increases. The PTC thermistor 6 can be selected based on the operating current, operating voltage, operating temperature, and reset temperature, as long as it is a positive temperature coefficient thermistor that limits the current by increasing its resistance with increasing temperature. The material and shape of the PTC thermistor 6 are not particularly limited as long as these characteristics are not impaired. In this embodiment, a ceramic sintered body containing barium titanate, strontium titanate, or calcium titanate is used. In addition to a ceramic sintered body, a so-called polymer PTC, in which conductive particles such as carbon are incorporated into a polymer, may also be used.

[0032] The case body 7 and the lid member 8 that constitute the resin case 10 are molded from thermoplastic resins such as flame-retardant polyamide, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT), etc. Materials other than resins may be used as long as they have properties equivalent to or better than those of the above-mentioned resins.

[0033] An accommodating recess 73 is formed on the first surface side of the case body 7, which is an internal space for accommodating the fixed contact 21, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, etc. The accommodating recess 73 has an opening 73a for accommodating the fixed contact 21 and the movable piece 4, an opening 73c for accommodating the movable piece 4 and the thermally responsive element 5, and an opening 73d for accommodating the PTC thermistor 6. The edges of the movable piece 4 and the thermally responsive element 5 incorporated in the case body 7 are abutted by frames that form the accommodating recess 73, and are guided when the thermally responsive element 5 undergoes reverse warpage deformation. In other words, the accommodating recess 73 accommodates the movable piece 4 and the thermally responsive element 5 in a deformable manner.

[0034] The lid member 8 is configured to cover the accommodating recess 73. The lid member 8 may be configured to cover at least a portion of the accommodating recess 73. A cover piece 9 made of a metal plate mainly composed of copper or stainless steel is embedded in the lid member 8 by insert molding. The cover piece 9 is embedded in the lid member 8 together with the fixed portion 43 of the movable piece 4 in a state of abutting against a first surface of the fixed portion 43. The cover piece 9 restricts the movement of the movable piece 4, and also contributes to the miniaturization of the breaker 1 while increasing the rigidity and strength of the lid member 8 and, by extension, the resin case 10 serving as the housing.

[0035] The case body 7 and the cover member 8 are formed by injection molding using the above-mentioned resin material. As already mentioned, the fixed piece 2 is inserted into the case body 7, and the movable piece 4 and the cover piece 9 are inserted into the cover member 8.

[0036] 1, a lid member 8 is attached to the case body 7 so as to close openings 73a, 73c, etc. of the case body 7, which houses the fixed piece 2, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, etc. The lid member 8 covers the housing recess 73. The case body 7 and the lid member 8 are joined by, for example, ultrasonic welding. In this way, the resin case 10 is formed.

[0037] 2 and 3 show an outline of the operation of the breaker 1. FIG. 2 shows the operation of the breaker 1 in a normal charging or discharging state. In a normal charging or discharging state, the thermally responsive element 5 maintains its initial shape before reverse warping. The movable contact 41 is pressed toward the fixed contact 21 by the elastic portion 44, so that the movable contact 41 and the fixed contact 21 come into contact with each other, and the fixed piece 2 and the movable piece 4 of the breaker 1 are brought into a state in which they can be electrically connected via the elastic portion 44 of the movable piece 4.

[0038] The elastic portion 44 of the movable piece 4 and the thermally responsive element 5 may be in contact. In this case, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, and the fixed piece 2 are electrically connected as a circuit. However, since the resistance of the PTC thermistor 6 is overwhelmingly greater than the resistance of the movable piece 4, the current flowing through the PTC thermistor 6 is substantially negligible compared to the amount of current flowing through the fixed contact 21 and the movable contact 41.

[0039] Figure 3 illustrates the operation of the breaker 1 during an overcharge or other abnormal condition. The thermally responsive element 5, which is constructed by laminating thin plates with different thermal expansion coefficients, deforms as the temperature rises, correcting its initial curved shape shown in Figure 2. When the thermally responsive element 5 reaches its operating temperature, it snaps into a reverse-bowed shape as shown in Figure 3. This causes the thermally responsive element 5 to contact the elastic portion 44 of the movable piece 4, which pushes the elastic portion 44 upward, separating the fixed contact 21 from the movable contact 41. At this time, the current flowing between the fixed contact 21 and the movable contact 41 is interrupted. Meanwhile, the thermally responsive element 5 contacts the movable piece 4, allowing a small leakage current to flow through the thermally responsive element 5 and the PTC thermistor 6. In other words, the PTC thermistor 6 establishes electrical continuity between the fixed piece 2 and the movable piece 4 via the thermally responsive element 5, which transitions the movable piece 4 to an interrupted state. As long as this leakage current flows, the PTC thermistor 6 continues to generate heat, maintaining the thermally responsive element 5 in a reversely curved state and dramatically increasing its resistance, so that the current does not flow through the path between the fixed contact 21 and the movable contact 41, and only the slight leakage current mentioned above exists (forming a self-holding circuit). This leakage current can be used for other functions of the safety device.

[0040] When the overcharged state is released or the abnormal state is resolved, the heat generated by the PTC thermistor 6 subsides, the temperature of the thermally responsive element 5 returns to the normal rotation return temperature, and the element 5 returns to its original shape. Then, the elastic force of the elastic portion 44 of the movable piece 4 brings the movable contact 41 and the fixed contact 21 back into contact, the circuit is released from the interrupted state, and the circuit returns to the conductive state shown in Figure 2.

[0041] 4 shows the lid member 8 in which the movable piece 4 and the cover piece 9 are embedded. The lid member 8 has an embedding portion 81 in which the movable piece 4 is embedded, and a first recess .

[0042] The embedded portion 81 embeds the fixed portion 43 of the movable piece 4. This allows the movable piece 4 to be fixed at an accurate position relative to the cover member 8. The embedded portion 81 is formed to extend in the short-side direction D1 of the movable piece 4 along the edge of the cover member 8 on the terminal 42 side. In this embodiment, the embedded portion 81 extends to the edge of the cover member 8 in the short-side direction D1.

[0043] The first recess 82 is recessed from the embedded portion 81 in the thickness direction of the cover member 8. The first recess 82 is formed across both outer sides of the movable piece 4 in the short-side direction D1. Furthermore, the first recess 82 in this embodiment is formed along the longitudinal direction D2 of the movable piece 4. The first recess 82 constitutes a part of an accommodating recess 83 that accommodates the movable contact 41 and the elastic portion 44 of the movable piece 4. By forming the first recess 82 in the cover member 8, the cover piece 9 is exposed in the accommodating recess 83.

[0044] 5 shows the case body 7 in which the fixing piece 2 is embedded. The case body 7 has a first protrusion 74 that protrudes toward the cover member 8. The first protrusion 74 is formed in a position and shape that corresponds to the first recess 82. When the cover member 8 is attached to the case body 7, the first protrusion 74 of the case body 7 is fitted into the first recess 82 of the cover member 8.

[0045] The engagement between the first recess 82 and the first protrusion 74 prevents the lid member 8 from shifting in position relative to the case body 7 during welding. At this time, the movable piece 4 is fixed in an accurate position relative to the lid member 8 by insert molding, so the movable piece 4 is accurately positioned relative to the case body 7 via the lid member 8. This prevents the movable piece 4 from shifting in position relative to the accommodating recess 63 due to vibration during welding, and prevents the generation of cutting powder.

[0046] The first protrusion 74 preferably includes a first side surface 74a perpendicular to the short-side direction D1 of the movable piece 4 and a second side surface 74b perpendicular to the long-side direction D2 of the movable piece 4. The first side surface 74a and the second side surface 74b are perpendicular to each other.

[0047] 4, the first recess 82 includes a third side surface 82a facing the first side surface 74a and a fourth side surface 82b facing the second side surface 74b. The abutment between the first side surface 74a and the third side surface 82a suppresses misalignment of the lid member 8 relative to the case body 7 in the short direction D1. The abutment between the second side surface 74b and the fourth side surface 82b suppresses misalignment of the lid member 8 relative to the case body 7 in the long direction D2.

[0048] 4, the cover member 8 has a first bottom surface 84a and a second bottom surface 84b. The first bottom surface 84a is formed from the periphery of the movable contact 41 to the side of the elastic portion 44. The second bottom surface 84b is formed in the embedded portion 81.

[0049] The embedded portion 81 protrudes toward the case body 7 since it embeds the fixed portion 43 of the movable piece 4. Therefore, the second bottom surface 84b protrudes toward the case body 7 more than the first bottom surface 84a.

[0050] 5, the case body 7 has a first top surface 75a and a second top surface 75b. The first top surface 75a is formed from the periphery of the fixed contact 21 to the periphery of the side of the accommodating recess 73. The second top surface 75b is formed on the side of the accommodating recess 73 that is closer to the terminal 42 of the movable piece 4.

[0051] 4 and 5, the height of second top surface 75b relative to first top surface 75a is set according to the height of second bottom surface 84b relative to first bottom surface 84a. Therefore, the height of first top surface 75a from the bottom surface (second surface) of case body 7 is formed higher than the height of second top surface 75b. When lid member 8 is attached to case body 7, first top surface 75a and first bottom surface 84a abut and are welded, and second top surface 75b and second bottom surface 84b abut and are welded.

[0052] A pair of first slopes 76 are formed on the case body 7. The first slopes 76 are formed on the outside of the first protrusions 74 in the short direction D1. The first slopes 76 are arranged between the first top surface 75a and the second top surface 75b, and connect the first top surface 75a and the second top surface 75b, which are at different heights. The first top surface 75a, the second top surface 75b, and the first slopes 76 form an outer periphery that continuously goes around the outer edge of the case body 7.

[0053] A pair of second slopes 85 are formed on the lid member 8. The second slopes 85 are formed at positions corresponding to the first slopes 76, i.e., on the outside of the first recess 82 in the short direction D1. The second slopes 85 are arranged between the first bottom surface 84a and the second bottom surface 84b, and connect the first bottom surface 84a and the second bottom surface 84b, which are at different heights. The first bottom surface 84a, the second bottom surface 84b, and the second slopes 85 form an outer periphery that continuously goes around the outer edge of the lid member 8.

[0054] When the lid member 8 is attached to the case body 7, the first slope 76 and the second slope 85 come into contact and are welded. The first slope 76 and the second slope 85 smoothly absorb the steps between the first top surface 75a and the second top surface 75b and the steps between the first bottom surface 84a and the second bottom surface 84b, easily improving the airtightness between the case body 7 and the lid member 8.

[0055] It is desirable that a rib 86 be formed on the second slope 85. The rib 86 is formed along the outer edge of the lid member 8 so as to protrude toward the case body 7. When the case body 7 and the lid member 8 are welded together, the rib 86 melts in the early stages, ensuring good welding between the case body 7 and the lid member 8.

[0056] It is desirable that the rib 86 be formed continuously from the second slope 85 to the embedded portion 81. In this embodiment, the rib 86 is formed continuously around the outer edge of the lid member 8 along the first bottom surface 84a, the second slope 85, and the second bottom surface 84b. Such a rib 86 further improves welding between the case body 7 and the lid member 8, and easily improves the airtightness between the case body 7 and the lid member 8.

[0057] A rib may be formed on the first slope 76 instead of the rib 86. In this case, it is desirable that the rib be formed continuously around the outer edge of the case body 7 along the first top surface 75a, the first slope 76, and the second top surface 75b.

[0058] A second recess 77 is formed in the case body 7. The second recess 77 is disposed closer to the fixed contact 21 than the opening 73c for accommodating the thermally responsive element 5. In this embodiment, the second recess 77 is provided on both sides of the fixed contact 21 in the short direction D1.

[0059] A second protrusion 87 is formed on the cover member 8. The second protrusion 87 is formed at a position corresponding to the second recess 77. When the cover member 8 is attached to the case body 7, the second protrusion 87 is fitted into the second recess 77. By fitting the second protrusion 87 into the second recess 77, the cover member 8 is more accurately positioned with respect to the case body 7 around the fixed contact 21 and the movable contact 41. In this embodiment, the fit between the first protrusion 74 and the first recess 82 and the fit between the second protrusion 87 and the second recess 77 allows the entire cover member 8 to be more accurately positioned and fixed to the case body 7.

[0060] The first protrusions 74 are preferably disposed outward in the longitudinal direction D2 from the accommodating recesses 73. With this configuration, the lid member 8 is more accurately positioned and fixed to the case body 7. Furthermore, the second recesses 77 are preferably disposed on the opposite side in the longitudinal direction D2 from the first protrusions 74, with the accommodating recesses 73 in between. With this configuration, the lid member 8 is more accurately positioned and fixed to the case body 7 in the vicinity of the four corners thereof.

[0061] The cover member 8 of this embodiment includes a protruding portion 88 that protrudes from the embedded portion 81 toward the movable contact 41. By providing the protruding portion 88, the movable piece 4 is sandwiched between the cover piece 9 and the protruding portion 88, and the movable piece 4 is firmly fixed to the cover member 8 in an accurate position.

[0062] The protruding portion 88 is preferably formed between the pair of first recessed portions 82. In other words, the first recessed portions 82 are preferably formed on both sides in the short direction D1 of the protruding portion 88. With this arrangement, the movable piece 4 is positioned with respect to the case body 7 even more accurately.

[0063] Although the breaker 1 of the present invention has been described in detail above, the present invention is not limited to the above-described specific embodiment, and can be modified and implemented in various aspects.

[0064] That is, the breaker 1 of the present invention is a breaker 1 that includes at least a fixed contact 21, a movable piece 4 that has an elastically deformable elastic portion 44 and a movable contact 41 at one end of the elastic portion 44, and presses the movable contact 41 into contact with the fixed contact 21, a thermally responsive element 5 that deforms with temperature changes, thereby transitioning the movable piece 4 from a conductive state in which the movable contact 41 is in contact with the fixed contact 21 to a cut-off state in which the movable contact 41 is separated from the fixed contact 21, a case main body 7 that has an accommodating recess 73 that accommodates the fixed contact 21, the movable piece 4, and the thermally responsive element 5, and a cover member 8 that is fixed to the case main body 7 and covers the accommodating recess 73, wherein the cover member 8 has an embedded portion 81 in which a portion of the movable piece 4 is embedded, and a first recess 82 that is recessed in the thickness direction of the cover member 8, and the case main body 7 has a first protrusion 74 that fits into the first recess 82. [Explanation of symbols]

[0065] 1: Breaker 4: Movable piece 5: Thermal response element 6: PTC thermistor (thermal response element) 7: Case body (first resin case) 8: Lid member (second resin case) 10: Resin case 21: Fixed contact 41: Movable contact 44: Elastic part 73: Storage recess 74: First convex part 74a: 1st side 74b: 2nd side 76: First slope 77: Second recess 81: Buried section 82: First recess 83: Storage recess 85: Second slope 86: Rib 87: Second convex part 88: Protrusion D1: Lateral direction D2: Longitudinal direction

Claims

1. A fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, the movable contact being pressed against the fixed contact to bring the movable contact into contact with the fixed contact; a thermally responsive element that deforms in response to a temperature change, thereby shifting the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having a first accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; a second resin case fixed to the first resin case and covering the first accommodating recess, the second resin case has a second accommodating recess that accommodates the movable piece, a embedding portion that embeds a portion of the movable piece, and a first recess that is recessed in a thickness direction of the second resin case, the first resin case has a first protrusion that fits into the first recess, the first protrusion includes a first side surface perpendicular to a short-side direction of the movable piece and a second side surface perpendicular to a long-side direction of the movable piece, The first recess constitutes a part of the second accommodating recess. breaker.

2. A fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, the movable contact being pressed against the fixed contact to bring the movable contact into contact with the fixed contact; a thermally responsive element that deforms in response to a temperature change, thereby shifting the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having a first accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; a second resin case fixed to the first resin case and covering the first accommodating recess, the second resin case has an embedding portion in which a portion of the movable piece is embedded, and a first recess portion recessed in a thickness direction of the second resin case, the first resin case has a first protrusion that fits into the first recess, the first resin case has a first slope formed on an outer side of the first protrusion in a short-side direction of the movable piece, the first slope is formed so that its height from the bottom surface of the first resin case decreases with increasing distance from the movable contact in the longitudinal direction of the movable piece, the second resin case has a second slope corresponding to the first slope; breaker.

3. A fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, the movable contact being pressed against the fixed contact to bring the movable contact into contact with the fixed contact; a thermally responsive element that deforms in response to a temperature change, thereby shifting the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having a first accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; a second resin case fixed to the first resin case and covering the first accommodating recess, the second resin case has an embedding portion in which a portion of the movable piece is embedded, and a first recess portion recessed in a thickness direction of the second resin case, the first resin case has a first protrusion that fits into the first recess, the first resin case has a first top surface and a second top surface adjacent to the first protrusion and at different heights from a bottom surface of the first resin case; breaker.

4. A fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, the movable contact being pressed against the fixed contact to bring the movable contact into contact with the fixed contact; a thermally responsive element that deforms in response to a temperature change, thereby shifting the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having a first accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; a second resin case fixed to the first resin case and covering the first accommodating recess, the second resin case has an embedding portion in which a portion of the movable piece is embedded, and a first recess portion recessed in a thickness direction of the second resin case, the first resin case has a first protrusion that fits into the first recess, the second resin case includes a protruding portion that protrudes from the embedded portion toward the movable contact, the first recesses are formed on both sides of the protrusion in a lateral direction of the movable piece, At least a portion of the first recess overlaps with at least a portion of the protrusion in the longitudinal direction of the movable piece. breaker.

5. A fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, the movable contact being pressed against the fixed contact to bring the movable contact into contact with the fixed contact; a thermally responsive element that deforms in response to a temperature change, thereby shifting the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having a first accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; a second resin case fixed to the first resin case and covering the first accommodating recess, the second resin case has an embedding portion in which a portion of the movable piece is embedded, and a first recess portion recessed in a thickness direction of the second resin case, the first resin case has a first protrusion that fits into the first recess, the first protrusion includes a first side surface perpendicular to a short-side direction of the movable piece and a second side surface perpendicular to a long-side direction of the movable piece, the first resin case has a first slope formed on an outer side of the first protrusion in a short-side direction of the movable piece, the second resin case has a second slope corresponding to the first slope, a rib protruding toward the first resin case along an outer edge of the second resin case is formed on the second slope; breaker.

6. A fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, the movable contact being pressed against the fixed contact to bring the movable contact into contact with the fixed contact; a thermally responsive element that deforms in response to a temperature change, thereby shifting the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having a first accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; a second resin case fixed to the first resin case and covering the first accommodating recess, the second resin case has an embedding portion in which a portion of the movable piece is embedded, and a first recess portion recessed in a thickness direction of the second resin case, the first resin case has a first protrusion that fits into the first recess, the second resin case includes a protruding portion that protrudes from the embedded portion toward the movable contact, the first recesses are formed on both sides of the protrusion in a lateral direction of the movable piece, the first resin case has a first slope formed on an outer side of the first protrusion in a short-side direction of the movable piece, the second resin case has a second slope corresponding to the first slope, a rib protruding toward the first resin case along an outer edge of the second resin case is formed on the second slope; breaker.

7. A fixed contact; a movable piece having an elastically deformable elastic portion and a movable contact at one end of the elastic portion, the movable contact being pressed against the fixed contact to bring the movable contact into contact with the fixed contact; a thermally responsive element that deforms in response to a temperature change, thereby shifting the movable piece from a conductive state in which the movable contact is in contact with the fixed contact to a cut-off state in which the movable contact is separated from the fixed contact; a first resin case having a first accommodating recess for accommodating the fixed contact, the movable piece, and the thermally responsive element; a second resin case fixed to the first resin case and covering the first accommodating recess, the second resin case has an embedding portion in which a portion of the movable piece is embedded, and a first recess portion recessed in a thickness direction of the second resin case, the first resin case has a first protrusion that fits into the first recess, the first resin case has a first slope formed on an outer side of the first protrusion in a short-side direction of the movable piece, the second resin case has a second slope corresponding to the first slope, a rib protruding toward the first resin case along an outer edge of the second resin case is formed on the second slope; breaker.

8. The first resin case has a first slope formed on the outside of the movable piece of the first convex portion in the short direction, 5. The breaker according to claim 1, wherein the second resin case has a second slope corresponding to the first slope.

9. A breaker as described in claim 2 or 8, wherein the second slope has a rib formed along the outer edge of the second resin case that protrudes toward the first resin case.

10. A breaker as described in claim 5, 6 or 9, wherein the rib is formed continuously from the second slope to the buried portion.

11. The first resin case has a second recess on the side of the fixed contact, The breaker according to claim 1 , wherein the second resin case has a second protrusion that fits into the second recess.

12. A breaker described in any one of claims 1 to 11, wherein the first convex portion is arranged further outward in the longitudinal direction of the movable piece than the first accommodating recess.

13. The second resin case includes a protruding portion protruding from the embedded portion toward the movable contact, 8. The breaker according to claim 1, wherein the first recess is formed on both sides of the protrusion in the short direction of the movable piece.

14. A safety circuit for electrical equipment, comprising a breaker as claimed in any one of claims 1 to 13.

15. A secondary battery pack equipped with a breaker described in any one of claims 1 to 13.

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