JP2017103118A - Breaker, safety circuit with the same, and secondary battery circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a breaker capable of easily attaining high capacity.SOLUTION: A breaker 1 comprises: a stationary piece 2 including a stationary contact 21; a movable piece 4 including a movable contact 41 and an elastic part 43 which is elastically deformed to press and bring the movable contact 41 into contact with the stationary contact 21; and a thermally-actuated element 5 which includes a thermal deformation part 51 that is thermally deformed with a temperature change, and a first abutment part 52 that is abutted with the movable piece 4 and in which, when the thermal deformation part 51 is thermally deformed, the first abutment part 52 drives the movable piece 4 and the movable piece 41 is separated from the stationary contact 21. A central portion 51a of the thermal deformation part 51 is arranged while being positionally displaced from a central portion 43a of the elastic part 43 in a planar view. Further, while the stationary contact 41 and the movable contact 42 are brought into contact with each other, the first abutment part 52 is separated from the movable piece 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a small breaker or the like built in a secondary battery pack or the like of an electric device.

  Conventionally, a breaker is used as a protection device (safety circuit) for secondary batteries and motors of various electric devices. When the temperature of the secondary battery during charging / discharging rises excessively, or when an abnormality occurs such as when an overcurrent flows through a motor or the like equipped in a device such as an automobile or home appliance, Cut off current to protect secondary batteries and motors. Breakers used as such protective devices operate accurately following temperature changes (having good temperature characteristics) and have stable resistance when energized to ensure the safety of the equipment. It is required to be.

  In addition, when the breaker is used as a protection device for a secondary battery or the like installed in an electric device such as a thin-type multifunctional mobile phone called a notebook personal computer, a tablet-type portable information terminal device, or a smartphone, the above-described case is used. In addition to ensuring safety, thinning is required. In particular, in recent portable information terminal devices, users have a strong tendency to reduce the thickness, and devices that are newly released by each company tend to be designed to be thinner in order to ensure superiority in design. It is remarkable. Against this background, a breaker mounted with a secondary battery as one component constituting a portable information terminal device is also strongly required to be thinner.

  The breaker is provided with a thermally responsive element that operates according to a temperature change and conducts or cuts off a current. Patent Document 1 discloses a breaker to which a bimetal is applied as a thermally responsive element. Bimetal is an element that is formed by laminating two types of plate-like metal materials having different coefficients of thermal expansion, and controls the conduction state of the contact by changing the shape in accordance with a temperature change. The breaker shown in the same document is a case in which parts such as a fixed piece, a movable piece, a thermally responsive element, and a PTC thermistor are housed in a case, and terminals of the fixed piece and the movable piece are connected to an electric circuit of an electric device. Used. In the breaker disclosed in Patent Document 1, the fixed piece is incorporated into the case body (resin base) by insert molding (see paragraph (0031) and the like of the same document).

WO2011 / 105175 gazette

  In recent years, with the improvement in performance of tablet-type and notebook-type personal computers, a breaker having a large current rating value and maximum allowable current value, that is, a high capacity, has been desired. In order to realize a high-capacity breaker, even if the amount of heat generated inside the breaker is larger than before due to a relatively large current flowing within the rating between the fixed piece and the movable piece, It is necessary that the thermoresponsive element does not operate (thermal deformation) and that its shape is maintained.

  By the way, in the breaker shown by the said patent document, the contact resistance which arises between a fixed contact and a movable contact becomes a big heat generation source inside a breaker. The heat generated at the fixed contact and the movable contact is conducted to the fixed piece and the movable piece.

  However, in the breaker shown in the above-mentioned patent document, since the thermally responsive element is arranged at a position adjacent to the movable piece, it is easy to be affected by the heat radiated from the movable piece, so that the capacity of the breaker can be increased. It was difficult.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a breaker capable of easily increasing the capacity.

  In order to achieve the above-described object, the present invention provides a fixed piece having a fixed contact, a movable piece having a movable contact and an elastic part that presses the movable contact against the fixed contact by elastic deformation, and a temperature change. And a first abutting portion that abuts on the movable piece due to thermal deformation of the thermal deforming portion, and the first abutting portion is deformed by the thermal deformation of the thermal deforming portion. In a breaker including a thermally responsive element that drives a movable piece and separates the movable contact from the fixed contact, the central portion of the thermally deformable portion is displaced from the central portion of the elastic portion in plan view. When the fixed contact and the movable contact are in contact with each other, the first contact portion is separated from the movable piece.

  In the breaker according to the present invention, it is desirable that the thermally deformable portion is disposed at a position that does not overlap with the elastic portion in plan view.

  In the breaker according to the present invention, it is preferable that a second abutting portion that abuts on the first abutting portion is provided at a distal end portion of the movable piece.

  The breaker according to the present invention further includes a case for housing the fixed piece, the movable piece, and the thermally responsive element, and the movable piece is a base end portion opposite to the tip end portion with the movable contact interposed therebetween. Therefore, it is desirable to be fixed to the case.

  The breaker according to the present invention preferably further includes a terminal piece connected to an external circuit, and a part of the terminal piece is embedded in the case and electrically connected to the base end.

  In the breaker according to the present invention, it is desirable that the base end portion, the movable contact, and the second contact portion are arranged in a straight line in this order.

  In the breaker according to the present invention, it is preferable that the elastic portion extends linearly, and the fixing piece includes an extending portion that extends in a direction intersecting with the elastic portion in plan view.

  In the breaker according to the present invention, it is preferable that the extending portion is provided on the side of the base end portion with respect to the fixed contact in a plan view.

  A safety circuit for an electric device according to the present invention includes the breaker.

  The secondary battery circuit according to the present invention includes the breaker.

  The breaker of the present invention has a fixed piece having a fixed contact, a movable contact and an elastic part that elastically deforms, a movable piece that presses and contacts the movable contact with the fixed contact, and thermally deforms as the temperature changes. And a thermally responsive element that drives the movable piece and separates the movable contact from the fixed contact. The thermally responsive element includes a thermally deformable portion that is thermally deformed in accordance with a temperature change and a first abutting portion that is in contact with the movable piece. In plan view, the center portion of the thermally deformable portion is the center of the elastic portion. The position is shifted from the part. Thereby, a heat deformation part becomes difficult to receive to the influence of the heat radiated | emitted from the movable piece, and the temperature change of a heat deformation part is suppressed. Furthermore, when the fixed contact and the movable contact are in contact, the first contact portion is separated from the movable piece, so that heat conduction from the movable piece to the thermally responsive element is suppressed. Therefore, the thermal stress generated in the thermally responsive element is suppressed, and the capacity of the breaker can be easily increased.

The perspective view before the assembly which shows schematic structure of the breaker by one Embodiment of this invention. Sectional drawing which shows the said breaker in a normal charge or discharge state. Sectional drawing which shows the said breaker in the overcharge state or the time of abnormality. The perspective view which shows the structure of the breaker before a cover member is mounted | worn with a case main body. The top view which shows the state by which the PTC thermistor, the thermoresponsive element, and the movable piece were integrated in the case main body of the said breaker. The top view which shows the modification of the said breaker. The top view which shows another modification of the said breaker. The top view which shows the structure of the secondary battery pack provided with the said breaker of this invention. The circuit diagram of the safety circuit provided with the said breaker of this invention.

  A breaker according to an embodiment of the present invention will be described with reference to the drawings. 1 to 3 show the configuration of the breaker. The breaker 1 includes a fixed piece 2 having a fixed contact 21, a terminal piece 3 on which a terminal is formed, a movable piece 4 having a movable contact 41 at the tip, a thermally responsive element 5 that deforms with a change in temperature, A PTC (Positive Temperature Coefficient) thermistor 6, a fixed piece 2, a terminal piece 3, a movable piece 4, a thermally responsive element 5, a case 7 for housing the PTC thermistor 6, and the like are included. The case 7 includes a case main body (first case) 71, a lid member (second case) 81 attached to the upper surface of the case main body 71, and the like.

  The fixed piece 2 is formed, for example, by pressing a metal plate mainly composed of copper or the like (other metal plate such as copper-titanium alloy, white or brass). The fixed piece 2 is embedded in the case body 71 by insert molding. A terminal 22 electrically connected to an external circuit is formed on one end side of the fixed piece 2, and a fixed contact 21 is formed on the other end side.

  The fixed contact 21 is formed at a position facing the movable contact 41 by clad, plating, coating, or the like of a conductive material such as copper, silver alloy, gold-silver alloy in addition to silver, nickel, nickel-silver alloy. The case 7 is exposed in the internal space. The terminal 22 protrudes outward from the edge of the case body 71.

  A support portion 23 for supporting the PTC thermistor 6 is formed between the fixed contact 21 and the terminal 22. The support part 23 is exposed in the internal space of the case 7. The PTC thermistor 6 is placed on the convex protrusions (dowels) 24 formed on the support portion 23 of the fixed piece 2 and supported by the protrusions 24.

  In the present application, unless otherwise specified, in the fixed piece 2, the surface on which the fixed contact 21 is formed (that is, the upper surface in FIG. 1) is the front surface and the opposite surface. Is described as the back side. The same applies to other parts, for example, the movable piece 4 and the thermally responsive element 5.

  The fixed piece 2 has step bent portions 25a and 25b bent in a crank shape in a side view. The step bent portion 25 a is formed between the support portion 23 and the terminal 22. The step bent portion 25 b is formed between the support portion 23 and the fixed contact 21. By providing the bent portions 25 a and 25 b in the fixed piece 2, a space for accommodating the PTC thermistor 6 is formed. In the present embodiment, the surface of the PTC thermistor 6 (that is, the upper end surface) is arranged lower than the surface of the fixed contact 21 and the surface of the terminal 22. Thereby, the breaker 1 can be downsized.

  Similarly to the fixed piece 2, the terminal piece 3 is formed by pressing a metal plate mainly composed of copper or the like. The terminal piece 3 is embedded in the case main body 71 by insert molding. A terminal 32 electrically connected to an external circuit is formed on one end side of the terminal piece 3, and a connection portion 33 electrically connected to the movable piece 4 is formed on the other end side. The terminal 32 protrudes outward from the edge of the case body 71. The connection portion 33 is exposed to the internal space of the case 7 and is electrically connected to the movable piece 4.

  The movable piece 4 is formed in an arm shape symmetrical to the center line in the longitudinal direction by pressing a plate-like metal material. As a material of the movable piece 4, a material mainly composed of copper or the like equivalent to the fixed piece 2 is preferable. In addition, a conductive elastic material such as copper-titanium alloy, white or brass may be used.

  A movable contact 41 is formed at the distal end of the movable piece 4 (in the present embodiment, slightly closer to the base end than the most distal end). The movable contact 41 is formed of the same material as the fixed contact 21 and is joined to the tip of the movable piece 4 by a technique such as clad or crimping in addition to welding.

  A base end portion 42 that is electrically connected to the connection portion 33 of the terminal piece 3 is formed on the side of the movable piece 4 opposite to the distal end portion. The base end portion 42 is provided with a protruding portion 42 a that protrudes toward the terminal 32. The protrusion 42a is used, for example, for transporting and positioning the movable piece 4. The connection part 33 of the terminal piece 3 and the base end part 42 of the movable piece 4 are fixed by welding, for example.

  The movable piece 4 has an elastic part 43 between the movable contact 41 and the base end part 42. The elastic part 43 extends linearly from the base end part 42 toward the movable contact 41 side. The movable piece 4 is fixed by being fixed to the connection portion 33 of the terminal piece 3 at the base end portion 42, and the elastic contact 43 is elastically deformed, whereby the movable contact 41 formed at the tip thereof is the back surface, that is, the fixed contact. The fixed piece 2 and the movable piece 4 can be energized by being pressed and brought into contact with the side 21. Since the movable piece 4 and the terminal piece 3 are electrically connected, the fixed piece 2 and the terminal piece 3 can be energized.

  The movable piece 4 is curved or bent at the elastic portion 43 by pressing. Thereby, the top part 45 is formed in the elastic part 43. In the present embodiment, the top portion 45 is provided on the base end portion 42 side. The degree of bending or bending is not particularly limited as long as the thermally responsive element 5 can be accommodated, and may be appropriately set in consideration of the elastic force at the operating temperature and the return temperature, the pressing force of the contact point, and the like.

  The thermally responsive element 5 has an initial shape whose cross section is curved in an arc shape, and is formed by laminating thin plate materials having different thermal expansion coefficients. When the operating temperature is reached due to overheating, the curved shape of the thermally responsive element 5 instantaneously undergoes reverse warping with a snap motion, and recovers when the temperature falls below the return temperature due to cooling. The initial shape of the thermoresponsive element 5 can be formed by pressing. As long as the elastic portion 43 of the movable piece 4 is pushed up by the reverse warping operation of the thermal response element 5 at a desired temperature and returns to the original state by the elastic force of the elastic portion 43, the material and shape of the thermal response element 5 are particularly limited. Although not intended, a rectangular shape is desirable from the viewpoint of productivity and efficiency of reverse warping operation, and it is desirable that the rectangular shape is close to a square in order to efficiently push up the elastic portion 43 while being small. Examples of the material of the thermally responsive element 5 include, for example, white, brass, and stainless steel including copper-nickel-manganese alloy or nickel-chromium-iron alloy on the high expansion side and iron-nickel alloy on the low expansion side. A laminate of two types of materials having different coefficients of thermal expansion made of various alloys such as steel is used in combination according to the required conditions.

  The PTC thermistor 6 is disposed between the fixed piece 2 and the thermally responsive element 5. That is, the fixed piece 2 is positioned directly below the thermal actuator 5 with the PTC thermistor 6 interposed therebetween. When the energization of the fixed piece 2 and the movable piece 4 is interrupted by the reverse warping operation of the thermal response element 5, the current flowing through the PTC thermistor 6 increases. As long as the PTC thermistor 6 is a positive temperature coefficient thermistor that limits the current by increasing the resistance value as the temperature rises, the type of operation current, operation voltage, operation temperature, return temperature, etc. can be selected as necessary. The material and shape are not particularly limited as long as these properties are not impaired. In the present embodiment, a ceramic sintered body containing barium titanate, strontium titanate or calcium titanate is used. In addition to the ceramic sintered body, a so-called polymer PTC in which conductive particles such as carbon are contained in a polymer may be used.

  The case main body 71 and the lid member 81 constituting the case 7 are formed of a thermoplastic resin such as flame retardant polyamide, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT) having excellent heat resistance. Has been. A material other than the resin may be applied as long as characteristics equal to or higher than those of the above-described resin can be obtained.

  The case main body 71 is formed with an accommodation recess 73 a for accommodating the movable piece 4 and an accommodation recess 73 b for accommodating the thermally responsive element 5 and the PTC thermistor 6. The housing recesses 73 a and 73 b are formed to be recessed downward from the upper end surface 72 of the case main body 71. The housing recesses 73 a and 73 b are arranged side by side in the longitudinal direction of the case main body 71. Therefore, the movable piece 4, the thermally responsive element 5, and the PTC thermistor 6 are mounted in a position shifted in the longitudinal direction of the case body 71 in the internal space of the case 7. The side wall of the housing recess 73 a is formed along the edge of the movable piece 4, and the side wall of the housing recess 73 b is formed along the edge of the thermally responsive element 5. At the time of reverse warping due to thermal deformation of the heat-responsive element 5, the movable piece 4 is guided by the side wall of the housing recess 73a, and the heat-responsive element 5 is guided by the side wall of the housing recess 73b.

  A cover piece 9 is embedded in the lid member 81 by insert molding. The cover piece 9 is formed by pressing a metal plate mainly composed of copper or the like, or a metal plate such as stainless steel. As shown in FIGS. 2 and 3, the cover piece 9 abuts on the surface of the movable piece 4 as appropriate to restrict the movement of the movable piece 4, and the lid member 81 and thus the rigidity and strength of the case 7 as the casing. Contributes to the downsizing of the breaker 1 Resin is disposed on the outer surface side of the cover piece 9.

  As shown in FIG. 1, the lid member 81 includes a case 81 so as to close the housing recess 73 a and the housing recess 73 b of the case body 71 that houses the fixed piece 2, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, and the like. Mounted on the main body 71. The case main body 71 and the lid member 81 are joined by, for example, ultrasonic welding. Thereby, the internal space of the case 7 by the accommodating recesses 73a and 73b is sealed, and components such as the movable piece 4, the thermally responsive element 5 and the PTC thermistor 6 can be shielded from the atmosphere outside the case 7 and protected.

  FIG. 2 shows the operation of the breaker 1 in a normal charge or discharge state. In a normal charging or discharging state, the thermal responsive element 5 maintains the initial shape (before reverse warping), the fixed contact 21 and the movable contact 41 are in contact, and the breaker 1 is connected through the elastic portion 43 of the movable piece 4. The terminals 22 and 32 are electrically connected.

  FIG. 3 shows the operation of the breaker 1 in an overcharged state or an abnormality. When the high temperature state is reached due to overcharge or abnormality, the thermally responsive element 5 that has reached the operating temperature is warped reversely due to thermal deformation, abuts against the elastic portion 43 of the movable piece 4, and the elastic portion 43 is further pushed up to cause the fixed contact 21. And the movable contact 41 are separated from each other. At this time, the current flowing between the fixed contact 21 and the movable contact 41 is interrupted. On the other hand, since the terminal piece 3, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6 and the fixed piece 2 are conductive as a circuit, a slight leakage current flows through the thermally responsive element 5 and the PTC thermistor 6. Become. Since the PTC thermistor 6 continues to generate heat as long as such a leakage current flows, the resistance value is drastically increased while maintaining the thermally actuated element 5 in the reverse warping state, so that the current is a path between the fixed contact 21 and the movable contact 41. There is only the above-described slight leakage current (which constitutes a self-holding circuit). This leakage current can be used for other functions of the safety device.

  When the overcharge state is canceled or the abnormal state is resolved, the heat generation of the PTC thermistor 6 is also stopped, and the thermal actuator 5 returns to the return temperature and is restored to the original initial shape. Then, the movable contact 41 and the fixed contact 21 come into contact again by the elastic force of the elastic portion 43 of the movable piece 4, the circuit is released from the interruption state, and returns to the conduction state shown in FIG. 2.

  FIG. 4 shows the breaker 1 before the cover member 81 is mounted after the parts such as the movable piece 4 are incorporated into the case main body 71. As already described, the movable piece 4 is fixed to the terminal piece 3 by welding. For this reason, a welding mark 46 is formed on the surface of the base end portion 42 of the movable piece 4. The case main body 71 is formed with a convex portion 74 protruding from the upper end surface 72. The convex portion 74 is formed around the base end portion 42 along the side wall of the housing concave portion 73a. The convex portion 74 is formed in a region excluding the periphery of the protruding portion 42 a of the movable piece 4. Thereby, interference with the protrusion part 42a and the convex part 74 is avoided. When the movable piece 4 is incorporated into the housing recess 73 a of the case body 71, the movable piece 4 is guided by the convex portion 74. Thereby, the positioning accuracy of the movable piece 4 at the time of welding is improved.

  On the inner surface side of the lid member 81, recesses 83a and 83b are provided for preventing interference with the movable piece 4 and the thermally responsive element 5 in the shut-off state shown in FIG. The recesses 83 a and 83 b are formed by being recessed from the lower end surface 82 of the lid member 81. A part of the cover piece 9 is exposed to the internal space of the case 7 by the recesses 83a and 83b.

  When the case member 7 is integrated by attaching the lid member 81 to the case body 71 and welding the upper end surface 72 and the lower end surface 82, the housing recess 73a of the case body 71 and the recess 83a of the lid member 81 Are opposed to each other, and the housing recess 73b of the case body 71 and the recess 83b of the lid member 81 are opposed to each other. The housing recess 73 a and the housing recess 73 b of the case main body 71 and the recesses 83 a and 83 b of the lid member 81 communicate with each other to form an internal space of the case 7. Such a structure of the case 7 can improve strength and rigidity while improving space efficiency and downsizing inside the breaker 1.

  The side wall of the recess 83a overlaps with the side wall of the housing recess 73a in plan view, and the side wall of the recess 83b overlaps with the side wall of the storage recess 73b in plan view. Therefore, the movable piece 4 is guided by the side wall of the accommodating recess 73a and the side wall of the recess 83a when the warp is caused by the thermal deformation of the thermoresponsive element 5. On the other hand, the thermally responsive element 5 is guided by the side wall of the housing recess 73b and the side wall of the recess 83b. Thereby, operation | movement of the movable piece 4 and the thermal response element 5 becomes smooth.

  The lid member 81 is provided with a pair of convex portions 84 projecting from the lower end surface 82. The convex portion 84 is formed at a position facing the corner portion 53 of the thermal response element 5 adjacent to the terminal 22. As shown in FIG. 3, the convex portion 84 abuts against the corner portion 53 of the thermally responsive element 5 that is thermally deformed, and regulates the posture of the thermally responsive element 5. Thereby, the displacement of the thermally responsive element 5 on the movable piece 4 side is increased, and a sufficient distance between the fixed contact 21 and the movable contact 41 can be ensured. The position and the number of the convex portions 84 are not particularly limited as long as the side adjacent to the terminal 22 of the thermal response element 5 (the side opposite to 52) can be pressed downward in FIG.

  The lid member 81 is provided with a pressing portion 85 that contacts the base end portion 42 of the movable piece 4 and presses the base end portion 42 toward the connection portion 33. The presser portion 85 has a shape that fits with the convex portion 74 of the case main body 71. A groove 86 that fits with the tip of the convex portion 74 is formed around the presser portion 85. Moreover, the recessed part 85a is formed in the center part of the press part 85, and interference with the press part 85 with the welding mark 46 of the movable piece 4 is avoided. The pressure between the base end portion 42 and the connection portion 33 is increased by the presser portion 85.

  The cover piece 9 is provided with a protruding portion 91 that protrudes toward the movable piece 4. As shown in FIG. 2, the protruding portion 91 abuts on the top portion 45 provided on the elastic portion 43 of the movable piece 4 and presses the top portion 45 downward. Thereby, the elastic part 43 is elastically deformed, and the pressure between the movable contact 41 and the fixed contact 21 is increased by the elastic force, and the contact resistance can be suppressed.

  FIG. 5 shows a state in which the PTC thermistor 6, the thermally responsive element 5, and the movable piece 4 are sequentially incorporated in the case body 71 in which the fixed piece 2 and the terminal piece 3 are embedded. The thermally responsive element 5 includes a thermally deformable portion 51 that thermally deforms with a temperature change and a first abutting portion 52 that abuts the movable piece 4.

  The thermal deformation portion 51 is a region that undergoes reverse warping deformation with snap motion due to a temperature change. For example, in a thermally responsive element having a dome-shaped snap element disclosed in Japanese Patent Application Laid-Open No. 2015-141886, the snap element corresponds to a thermal deformation portion.

  On the other hand, the first contact portion 52 is provided in the edge region of the thermally responsive element 5. That is, the first contact portion 52 is provided outside the thermal deformation portion 51. For example, in a thermally responsive element having a flange portion provided on the outer peripheral edge of a snap element disclosed in JP-A-2015-141886, the flange portion can be applied to the first contact portion.

  As shown in FIG. 2, the first contact portion 52 is separated from the movable piece 4 when the fixed contact 21 and the movable contact 41 are in contact with each other. Thereby, the heat conduction from the movable piece 4 to the thermoresponsive element 5 is suppressed, and the temperature rise of the thermoresponsive element 5 can be suppressed.

  The present invention has been completed by finding that the positional relationship between the central portion 51a of the thermal deformation portion 51 and the central portion 43a of the elastic portion 43 of the movable piece 4 significantly affects the operating temperature of the breaker 1. In other words, in the breaker 1 of the present embodiment, the central portion 51a of the thermal deformation portion 51 is arranged so as to be displaced in the longitudinal direction of the breaker 1 from the central portion 43a of the elastic portion 43 in plan view. Such a breaker 1 can suppress the width | variety (length of a transversal direction) and thickness, and contributes to the improvement of the design freedom of an electric equipment.

  In the breaker 1 of the present embodiment, since the central portion 51a of the thermal deformation portion 51 is arranged so as to be displaced from the central portion 43a of the elastic portion 43 in plan view, the thermal deformation portion 51 radiates from the movable piece 4. It becomes difficult to be influenced by the heat that is applied, and the temperature change of the thermal deformation portion 51 is suppressed. Therefore, coupled with the suppression of the heat conduction from the movable piece 4 to the thermally responsive element 5 described above, the thermal stress of the thermal deformation portion 51 is reduced, and the thickness of the breaker 1 is suppressed, and the breaker 1 can be easily formed. It is possible to increase the capacity. The present invention is particularly effective in an ultra-thin breaker having a thickness of about 1 mm, for example.

  On the other hand, the first abutting portion 52 abuts on the movable piece 4 and is disposed at a position overlapping the movable piece 4 in a plan view in relation to driving the movable piece 4. However, since the first contact portion 52 is provided at the end edge portion of the thermally responsive element 5, the thermal stress generated in the first contact portion 52 even if the temperature changes in the first contact portion 52. Is small, and the influence on the operation of the movable piece 4 is suppressed.

  For example, according to the breaker 1 configured such that the central portion 51a of the thermal deformation portion 51 is displaced from the central portion 43a of the elastic portion 43 in a plan view, a high capacity of several percent or more It has been confirmed by the inventor's experiment that this can be achieved.

  In the present embodiment, the thermal deformation portion 51 is arranged at a position that does not overlap with the elastic portion 43 in plan view. According to such an arrangement of the thermal deformation portion 51 and the elastic portion 43, the heat of the elastic portion 43 becomes more difficult to be transmitted by the thermal deformation portion 51, and the thermal stress of the thermal deformation portion 51 is suppressed. Therefore, it is possible to easily increase the capacity of the breaker 1.

  For example, the inventor is able to achieve a capacity increase of 30% or more according to the breaker 1 having such a configuration in which the thermal deformation portion 51 is arranged at a position that does not overlap with the elastic portion 43 in plan view. Has been confirmed by experiments.

  As shown in FIGS. 1 to 4, the movable piece 4 has a second contact portion 44 that contacts the first contact portion 52 at the distal end thereof. The second contact portion 44 is formed to have a narrower shape than the elastic portion 43. Thereby, heat conduction from the movable contact 41 to the second contact portion 44 is suppressed. The second contact portion 44 is formed with a convex portion 44 a that protrudes to the back surface side, that is, the first contact portion 52 side and contacts the first contact portion 52. By providing the convex portion 44a in the second contact portion 44, a sufficient distance between the fixed contact 21 and the movable contact 41 in the interrupted state shown in FIG. The operation speed to the shut-off state is improved. In addition, it is possible to reduce the size of the thermally responsive element 5.

  In the present embodiment, the elastic portion 43 and the second contact portion 44 are integrally formed by a single metal plate. For this reason, elastic deformation can also occur in the second contact portion 44. However, since the second contact portion 44 is provided in the region on the distal end side of the movable piece 4 with respect to the movable contact 41, the elastic deformation in the second contact portion 44 fixes the movable contact 41. No contribution is made when the contact 21 is pressed.

  The movable piece 4 is fixed to the case main body 71 via the connection portion 33 of the terminal piece 3 at the base end portion 42 opposite to the distal end portion with the movable contact 41 interposed therebetween. Thereby, the elastic part 43 can press the movable contact 41 to the fixed contact 21 with a large force, the contact resistance between the contacts is reduced, and the heat generation in the internal space of the case 7 is suppressed. Therefore, the capacity of the breaker 1 can be further increased.

  In the present embodiment, a part of the terminal piece 3 (the other end side) is embedded in the case body 71 and is electrically connected to the base end portion 42 by welding or the like at the connection portion 33. Therefore, a configuration in which the base end portion 42 is fixed to the case main body 71 can be realized simply.

  The base end portion 42, the movable contact 41, and the second contact portion 44 are arranged on a straight line. That is, the movable contact 41 is disposed on a line connecting the base end portion 42 and the second contact portion 44. Moreover, the base end portion 42, the movable contact 41, and the second contact portion 44 are arranged in this order from the terminal piece 3 side toward the fixed piece. With such an arrangement, it is possible to reduce the size of the breaker 1 in the short direction, and the degree of freedom of mounting the breaker 1 on an electric device is improved.

  FIG. 6 shows a breaker 1 </ b> A that is a modification of the breaker 1. In the figure, a plan view of the breaker 1A before the cover member 81 is mounted is shown. Regarding the portion of the breaker 1 </ b> A that is not described below, the configuration of the breaker 1 described above can be appropriately employed.

  In the breaker 1A, the shape of the fixed piece 2A is different from that of the fixed piece 2 of the breaker 1. The fixed piece 2 shown in FIG. 5 extends linearly in the longitudinal direction of the breaker 1 from the terminal 22 on one end side to the fixed contact 21 on the other end side through the support portion 23. Therefore, the current path in the fixed piece 2 in the conductive state shown in FIG. 2 extends from the terminal 22 to the fixed contact 21 via the support portion 23.

  On the other hand, in the fixed piece 2A shown in FIG. 6, the extending part 25 orthogonal to the longitudinal direction of the breaker 1A is provided in plan view, and the fixed contact 21 and the extending part 25 are connected from the support part 23 on one end side. Then, it extends in an L shape in plan view up to the terminal 22 on the other end side. That is, the extending part 25 extends in a direction orthogonal to the elastic part 43 of the movable piece 4 in plan view.

  In the breaker 1 </ b> A, the current path in the fixed piece 2 </ b> A in the conductive state extends from the terminal 22 to the fixed contact 21 without passing through the support portion 23 positioned below the thermal response element 5. Therefore, in the breaker 1, since the resistance value is reduced by shortening the current path in the fixed piece 2A, the capacity can be further increased. In addition, since heat generation at the support portion 23 located immediately below the thermally responsive element 5 in the fixed piece 2A is suppressed, it is possible to further increase the capacity. From the viewpoint of shortening the current path in the fixed piece 2A in the conductive state while separating the terminal 22 and the terminal 32, the extending direction of the extending portion 25 is the elastic portion 43 of the movable piece 4 in plan view. However, it is sufficient that the direction intersects with the elastic portion 43 of the movable piece 4 in a plan view.

  In the fixed piece 2 </ b> A, it is desirable that the extending portion 25 is provided on the base end portion 42 side of the movable piece 4 with respect to the fixed contact 21 in a plan view. In the present modification, the extending portion 25 extends in the short direction of the breaker 1A from between the fixed contact 21 and the base end portion 42 in a plan view. As a result, the current path in the conductive state can be concentrated on the base end portion 42 side, that is, on the side farther from the thermal actuator 5 than the fixed contact 21 and the movable contact 41. Therefore, the heat generation around the thermally responsive element 5 is further suppressed, and the capacity of the breaker 1A can be further increased.

  The fixed piece 2 </ b> A is not limited to an L-shape in plan view, and the terminal 22 extends in the same direction as the terminal 32 and has a crank-like shape in plan view, or the terminal 22 extends in the direction opposite to the terminal 32. It may be U-shaped when viewed in plan.

  FIG. 7 shows breakers 1B and 1C which are another modified example of the breaker 1. In the figure, a plan view of the breakers 1B and 1C before the cover member 81 is mounted is shown.

  The breakers 1B and 1C are such that the movable piece 4, the thermally responsive element 5 and the PTC thermistor 6 are arranged so as to be displaced in the short direction of the breakers 1B and 1C. Is different. Accordingly, the shapes of the case main body 71, the fixed piece 2 and the like are also changed. Of the breakers 1B and 1C, the configuration of the breaker 1 described above can be adopted as appropriate for portions not described below.

  Even in the breakers 1B and 1C, the central portion 51a of the thermal deformation portion 51 is arranged so as to be displaced from the central portion 43a of the elastic portion 43 in plan view. As a result, similarly to the breaker 1, the heat transmitted from the movable contact 41 to the elastic portion 43 is less likely to be transmitted to the thermal deformation portion 51, the thermal deformation of the thermal deformation portion 51 is suppressed, and the capacity can be easily increased. It becomes possible. In the breakers 1B and 1C, the length of the case main body 71 and thus the breakers 1B and 1C can be shortened while maintaining the capacity as high as that of the breaker 1.

  In the breaker 1C, the thermally responsive element 5 and the PTC thermistor 6 are more significantly displaced from the breaker 1B. That is, the thermal deformation portion 51 is arranged at a position that does not overlap with the elastic portion 43 in plan view. Accordingly, the second contact portion 44 is formed at a position extending from the elastic portion 43 in the short direction of the movable piece 4. According to such a breaker 1C, the heat of the elastic portion 43 is more difficult to be transmitted to the thermal deformation portion 51, the thermal deformation of the thermal deformation portion 51 is suppressed, and the capacity can be easily increased.

  The present invention is not limited to the configuration of the above-described embodiment, but at least the fixed piece 2 having the fixed contact 21 and the elastic part that presses and contacts the movable contact 41 to the fixed contact 21 by elastic deformation with the movable contact 41. 43, a thermally deformable portion 51 that thermally deforms in accordance with a temperature change, and a first abutting portion 52 that abuts the movable piece 4, and the first deformation is caused by thermal deformation of the thermally deformable portion 51. The contact portion 52 includes a thermally responsive element 5 that drives the movable piece 4 and the movable contact 41 is separated from the fixed contact 21, and the central portion 51 a of the thermal deformation portion 51 is a central portion 43 a of the elastic portion 43 in plan view. When the fixed contact 21 and the movable contact 41 are in contact with each other, the first contact portion 52 only needs to be separated from the movable piece 4.

  For example, the fixed piece 2 may be extended to the terminal piece 3 side. In this case, the terminal 32 of the terminal piece 3 and the terminal 22 of the fixed piece 2 may overlap in plan view. Moreover, as a support structure of the movable piece 4, a structure in which the movable piece 4 is joined to the cover piece as shown in JP 2014-235913 A may be applied to the present invention.

  The case 7 may be sealed with resin or the like by secondary insert molding or the like. In this case, the terminal 22 of the fixed piece 2 and the terminal 32 of the terminal piece 3 may be exposed from the resin formed on the outer side of the case 7 so as to be fixed to and conductive with a land such as a circuit board.

  Moreover, the joining method of the case main body 71 and the lid member 81 is not limited to ultrasonic welding, and can be appropriately applied as long as both are firmly joined. For example, a liquid or gel adhesive may be applied, filled, and cured to bond them together. Further, for joining the case main body 71 and the lid member 81, a technique such as caulking can be used. Such a technique is particularly effective when a metal is disposed at the joint between the two. Further, the case 7 is not limited to the form constituted by the case main body 71 and the lid member 81, but may be constituted by two or more parts.

  In the present embodiment, the PTC thermistor 6 has a self-holding circuit, but it can be applied even in a form in which such a configuration is omitted, while ensuring stable temperature followability and resistance value. The breaker 1 can be downsized.

  Alternatively, the movable piece 4 and the thermally responsive element 5 may be integrally formed by forming the movable piece 4 from a laminated metal such as bimetal or trimetal. In this case, the configuration of the breaker is simplified and the size can be reduced.

  Further, the shapes of the fixed piece 2, the terminal piece 3, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, the housing recess 73, and the like are not limited to those shown in FIG.

  Moreover, you may apply this invention to the form by which the terminal piece 3 and the movable piece 4 are integrally formed as shown by the said patent document 1. FIG. In this case, the integrated terminal piece 3 and movable piece 4 are sandwiched and welded between the case body 71 and the lid member 81, for example.

  Further, the breaker 1 of the present invention can be widely applied to secondary battery packs, safety circuits for electric devices, and the like. FIG. 8 shows a secondary battery pack 500. The secondary battery pack 500 includes a secondary battery 501 and a breaker 1 provided in the output terminal circuit of the secondary battery 501. FIG. 9 shows a safety circuit 502 for electrical equipment. The safety circuit 502 includes the breaker 1 in series in the output circuit of the secondary battery 501. According to the secondary battery pack 500 or the safety circuit 502 including the breaker 1, the secondary battery pack 500 or the safety circuit 502 that can ensure a good current interruption operation can be manufactured.

DESCRIPTION OF SYMBOLS 1 Breaker 2 Fixed piece 21 Fixed contact 3 Terminal piece 4 Movable piece 41 Movable contact 42 Base end part 43 Elastic part 43a Center part 44 2nd contact part 5 Thermally responsive element 51 Thermal deformation part 51a Center part 52 1st contact part 7 Case 71 Case body 501 Secondary battery 502 Safety circuit

Claims (10)

A fixed piece having a fixed contact;
A movable piece having a movable contact and an elastic part that presses and contacts the movable contact with the fixed contact by elastic deformation;
A heat deforming portion that is thermally deformed in accordance with a temperature change; and a first contact portion that contacts the movable piece by the heat deformation of the heat deforming portion, and the first contact portion is formed by the heat deformation of the heat deforming portion. A breaker comprising a thermally responsive element that drives the movable piece and separates the movable contact from the fixed contact;
In plan view, the central portion of the thermally deformable portion is arranged to be displaced from the central portion of the elastic portion,
The breaker, wherein the first contact portion is separated from the movable piece when the fixed contact and the movable contact are in contact with each other.   The breaker according to claim 1, wherein the thermal deformation portion is arranged at a position that does not overlap with the elastic portion in plan view.   The breaker according to claim 1 or 2, wherein a second contact portion that contacts the first contact portion is provided at a tip portion of the movable piece. A case that accommodates the fixed piece, the movable piece, and the thermally responsive element;
The breaker according to claim 3, wherein the movable piece is fixed to the case at a base end portion opposite to the tip end portion with the movable contact in between. A terminal piece connected to an external circuit;
The breaker according to claim 4, wherein a part of the terminal piece is embedded in the case and electrically connected to the base end portion.   The breaker according to claim 4 or 5, wherein the base end portion, the movable contact point, and the second contact portion are arranged in a straight line in this order. The elastic part extends linearly,
The breaker according to any one of claims 1 to 6, wherein the fixing piece includes an extending portion that extends in a direction intersecting with the elastic portion in a plan view.   The breaker according to claim 7, wherein the extension portion is provided closer to the base end portion than the fixed contact in a plan view.   A safety circuit for electrical equipment, comprising the breaker according to any one of claims 1 to 8.   A secondary battery circuit comprising the breaker according to claim 1.

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