JP6099080B2 - Non-energized breaker - Google Patents

Description

The present invention relates to a non-energized breaker for a battery pack that cuts off a current when the temperature is higher than a preset temperature.

  Devices such as battery packs and motors can improve safety by interrupting current when the temperature is abnormally high. For this purpose, a non-energized breaker that switches the contact off when the set temperature is reached is used. For example, a battery pack with a built-in lithium ion battery becomes hot when charged and discharged under abnormal conditions of use, so it has a built-in non-energized type breaker, which cuts off current at abnormally high temperatures and is safe. Can be used for In addition, the temperature of motors, etc. may become abnormally high when an overload or abnormal current flows. In this state, the current is interrupted by a non-energized breaker to protect the motor and use it safely. it can.

As a breaker used for such an application, a breaker that cuts off a current in an abnormal state has been developed. (See Patent Document 1)
As shown in FIG. 1, this breaker is an energization type breaker having a bimetal 108 as a movable contact metal plate 106. In this breaker, when the ambient temperature rises to the set temperature, the movable contact metal plate of the bimetal 108 is reversed and switched to the off state. The breaker having this structure has a disadvantage that the movable contact metal plate is made of a bimetal, so that the electric resistance of the movable contact metal plate is large and the power loss due to the voltage drop of the breaker is large. In addition, even when the ambient temperature does not rise to the set temperature, there is a drawback that it can be switched to the off state when the flowing current increases. This is because the movable contact metal plate having a large electric resistance generates heat due to the Joule heat of the current and reverses.

  As a breaker that solves the above-mentioned defects of the breaker, a non-energized breaker has been developed in which a bimetal and a movable contact metal plate are separate metal plates, and a heater for heating the bimetal is built in. (See Patent Document 2)

  This breaker is shown in the cross-sectional views of FIGS. FIG. 2 shows an ON state in which the bimetal 108 is not reversed and the movable contact 107 is brought into contact with the fixed contact 105. FIG. 3 shows an OFF state in which the bimetal 108 is reversed and the movable contact 107 is separated from the fixed contact 105. ing.

JP 2006-100054 A JP 2002-56755 A

  The breaker shown in FIGS. 2 and 3 is deformed so that the bimetal 108 is reversed when the temperature is higher than the set temperature, and the reversed bimetal 108 pushes up the movable contact metal plate 106 from below, and the movable contact 107 is fixed to the fixed contact 105. The current is cut off in the off state. When the temperature is lowered and the bimetal 108 is restored to its original shape, the movable contact 107 is brought into contact with the fixed contact 105 by the elasticity of the movable contact metal plate 106 to return to the ON state. The movable contact metal plate 106 elastically presses the movable contact 107 against the fixed contact 105 in a state where the movable metal plate 106 is not pushed up by the bimetal 108, that is, in a state where the bimetal 108 does not reverse with temperature. That is, in this state, the movable contact 107 is brought into contact with the fixed contact 105 by the elasticity of the movable contact metal plate 106 and is kept in the on state.

  In the non-energized breaker described above, when the ambient temperature becomes higher than the set temperature, the bimetal is reversed and the contact of the movable contact metal plate is separated from the fixed contact metal plate and switched to the off state. In the non-energized breaker having this structure, the movable contact metal plate is not made of bimetal, so that the electric resistance of the movable contact metal plate can be reduced. However, even in a non-energized breaker having this structure, when the current of the breaker increases in a state where the ambient temperature does not rise to the set temperature, the bimetal may be reversed and switched to the off state. This is because the movable contact metal plate generates heat due to the Joule heat of the current, and the heated movable contact metal plate heats and inverts the bimetal. In particular, when the ambient temperature is high, the bimetal is easily inverted due to heat generated by the movable contact metal plate, and even when the ambient temperature does not rise to the set temperature, the current may be switched to the off state. The non-energized breaker having this characteristic may be switched to an off state even when the set temperature is not reached, so that it cannot be used in an application in which a large current flows, and there is a drawback that the application is limited.

  The above disadvantages can be prevented by increasing the cross-sectional area of the movable contact metal plate, that is, as a thick metal plate, by reducing the electrical resistance. This is because the heat generated by the Joule heat of the movable contact metal plate increases in proportion to the product of the square of the current and the electrical resistance. However, when a thick metal plate is used as the movable contact metal plate, the bimetal is inverted and the temperature at which the movable contact of the movable contact metal plate is switched off also changes, so the temperature at which the movable contact metal plate is switched off is adjusted to the set value. Becomes difficult. This is because the set temperature at which the contact is turned off is specified by the elasticity of the movable contact metal plate and the bimetal, that is, the balance of Young's modulus. In particular, a non-energized breaker built in a battery pack or the like is required to be extremely small, with a total thickness of about 1 mm. Therefore, the elastic balance between the movable contact metal plate and the bimetal is turned off. It is extremely difficult to increase the maximum current that can be switched to the OFF state while keeping the set temperature to be switched within a specific temperature range.

The present invention has been developed for the purpose of solving the above-mentioned drawbacks. An important object of the present invention is to provide a non-energized breaker for a battery pack that can stably and reliably be switched off when the ambient temperature reaches a set temperature while increasing the maximum current that can be switched off by current. There is to do.

Means for Solving the Problems and Effects of the Invention

A non-energized breaker for a battery pack according to the present invention includes an outer case 1, a fixed contact metal plate 4 having a fixed contact 5 fixed to the outer case 1, and a fixed contact 5 of the fixed contact metal plate 4. A movable contact metal plate 6 which has a movable contact 7 at a position opposite to the outer casing 1 and is partially fixed to the outer case 1 so that the movable contact 7 can be moved, and the movable contact metal plate 6 and the fixed contact metal. And a bimetal 8 which is disposed between the plate 4 and is deformed at an ambient temperature to switch the movable contact metal plate 6 from on to off. When the bimetal 8 does not press the movable contact metal plate 6, the non-energized breaker described above is turned on by bringing the movable contact 7 into contact with the fixed contact 5 due to the elasticity of the movable contact metal plate 6. 8 is deformed, and the deformed bimetal 8 presses the movable contact metal plate 6 to move the movable contact 7 away from the fixed contact 5 to be switched off. Further, in the above-mentioned non-energized type breaker, the movable contact metal plate 6 is made of Cu—Ni—P alloy containing 0.1 wt% or more and 2 wt% or less of nickel in addition to phosphorus.

The above-described non-energized breaker for a battery pack has a feature that the maximum current that can be switched to an off state by a current is increased, and that the switch can be stably and reliably switched to an off state when the ambient temperature reaches a set temperature. This is because the above-mentioned non-energized type breaker makes the movable contact metal plate a Cu-Ni-P alloy containing 0.1% by weight or more and 2% by weight or less nickel in addition to phosphorus. . The Cu-Ni-P alloy used for the movable contact metal plate achieves elasticity comparable to that of phosphor bronze used in conventional breakers, while reducing the amount of heat generated by Joule heat generated by the flowing current. Can be small. For this reason, the maximum current that can be switched to the OFF state by the heat generated by the current flowing through the movable contact metal plate is increased, and a feature that can be reliably switched to the OFF state at the set temperature is realized.

In the non-energized breaker for a battery pack according to the present invention, the movable contact metal plate is made of a Cu—Ni—P alloy containing 0.05 wt% or more and 0.3 wt% or less of phosphorus.
The above-described non-energized breaker for a battery pack has a feature that the maximum current that can be switched to the off state can be increased while realizing the excellent elasticity of the movable contact metal plate.

In the non-energized type breaker for a battery pack of the present invention, the movable contact metal plate is made of a Cu—Ni—P alloy containing 0.02 wt% or more and 0.5 wt% or less of zinc in addition to nickel. Furthermore, the movable contact metal plate is a Cu—Ni—P alloy containing 0.02 wt% or more and 0.5 wt% or less of iron in addition to nickel.
The non-energized type breaker for the battery pack described above can increase the maximum current that can be switched to the off state by the current while realizing better elasticity of the movable contact metal plate.

In the non-energized type breaker for the battery pack of the present invention, the fixed contact metal plate can be a Cu-Cr alloy containing tin, zinc, and chromium. This non-energized type breaker for battery packs has the feature that it can be connected to the fixed contact metal plate by spot welding of the lead plate stably and securely while increasing the maximum current that can be switched off by the flowing current. .

Furthermore, the non-energized type breaker for the battery pack of the present invention can arrange a heater 9 for heating the bimetal 8 between the bimetal 8 and the fixed contact metal plate 4. The non-energized breaker for a battery pack having this structure is characterized in that in the off state, the bimetal is heated by a heater and can be held in the off state without returning to the on state.

Moreover, the non-energized type breaker for the battery pack of the present invention uses the heater 9 as a PTC heater to maintain the heater temperature at the set temperature and to heat the bimetal to the set temperature with the set temperature heater. The bimetal heated to the set temperature can be kept off. This non-energized type breaker for a battery pack has a feature that it can be stably kept in an off state by a heated bimetal without heating the heater to an abnormal temperature.

It is sectional drawing of the conventional breaker. It is sectional drawing which shows the ON state of the conventional breaker. It is sectional drawing which shows the OFF state of the breaker shown in FIG. It is a perspective view of the breaker concerning one Example of this invention. It is a vertical longitudinal cross-sectional view of the breaker shown in FIG. It is sectional drawing which shows the OFF state of the breaker shown in FIG. It is the VII-VII sectional view taken on the line of the breaker shown in FIG. It is the VIII-VIII sectional view taken on the line of the breaker shown in FIG. It is the IX-IX sectional view taken on the line of the breaker shown in FIG. It is sectional drawing which shows another example of a connection rib, Comprising: It is a figure corresponded in the XX cross section of FIG. It is sectional drawing which shows another example of a connection rib, Comprising: It is a figure corresponded in the VII-VII line cross section of FIG. It is sectional drawing which shows an example which mounts the breaker shown in FIG. 4 on a circuit board. It is sectional drawing which shows another example which mounts the breaker shown in FIG. 4 on a circuit board. It is sectional drawing which shows another example which mounts the breaker shown in FIG. 4 on a circuit board. It is a perspective view of the breaker concerning the other Example of this invention. It is a vertical longitudinal cross-sectional view of the breaker shown in FIG. It is the XVII-XVII sectional view taken on the line of the breaker shown in FIG. It is a top view of the breaker shown in FIG. It is sectional drawing which shows an example which mounts the breaker shown in FIG. 15 on a circuit board. FIG. 6 is a circuit diagram for measuring a current at which a breaker is switched off.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment shown below exemplifies a non-energized type breaker for embodying the technical idea of the present invention, and the present invention does not specify the breaker as follows. Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The following non-energized breakers are built in the battery pack and used for applications that interrupt the current by deforming the bimetal when the battery or ambient temperature is high, or when the battery pack is used in an abnormal condition. Is done.

  The breaker shown in FIGS. 4 to 9 includes a fixed contact metal plate 4 having a fixed contact 5, a movable contact metal plate 6 in which a movable contact 7 is disposed at a position facing the fixed contact 5, and the movable contact metal plate. A bimetal 8 arranged at a position for switching 6 on and off, a fixed contact 5 of the fixed contact metal plate 4, and a movable contact 7 of the movable contact metal plate 6, and the bimetal 8 arranged inside. The outer case 1 is provided. When the breaker is in an ON state, the bimetal does not press the movable contact metal plate, and the movable contact is pressed against the fixed contact by the elasticity of the movable contact metal plate. When the ambient temperature rises to a high temperature, the bimetal 8 is deformed by this temperature rise, the deforming bimetal 8 presses the movable contact metal plate 6, deforms it, and moves the movable contact 7 away from the fixed contact 5. To the off state. Further, when the ambient temperature drops to a predetermined temperature, the breaker returns to the movable contact metal plate 6 and the bimetal 8, and the movable contact 7 is brought into contact with the fixed contact 5 to be switched on.

  The breaker shown in FIGS. 4 to 9 fixes a fixed contact metal plate 4 and a movable contact metal plate 6 to the exterior case 1 and deforms the movable contact metal plate 6, and adds the bimetal 8. A heater 9 for heating is incorporated. Since the breaker shown in the figure has a built-in heater 9 for heating the bimetal 8, the breaker is optimally used for heating the bimetal 8 with the heater 9 to keep the current cut off. However, the breaker does not necessarily need to have a built-in heater for heating the bimetal.

  The outer case 1 is formed of a plastic insulating case 2 and an outer metal plate 3. The outer case 1 has the fixed contact metal plate 4 inserted and fixed to the bottom 13 of the insulating case 2 and fixed to the upper surface of the outer metal plate 3. The insulating case 2 is provided at both end portions so as to project the first outer wall 11A and the second outer wall 11B, and a storage space 20 is provided between the first outer wall 11A and the second outer wall 11B. Yes. The storage space 20 is closed at the bottom with the fixed contact metal plate 4 that is fixed by insert molding, and closed at the top with the exterior metal plate 3. Therefore, the exterior case 1 has the fixed contact metal plate 4 exposed on the bottom surface and the exterior metal plate 3 exposed on the top surface. The exterior metal plate 3 is not fixed by insert molding to the plastic insulating case 2, and almost the entire surface is exposed to the upper surface side.

  The insulating case 2 is provided with opposing walls 12 that connect the first outer wall 11 </ b> A and the second outer wall 11 </ b> B on both sides of the storage space 20, and the opposing wall 12 and the outer wall 11 surround the storage space 20. The surrounding outer peripheral wall 10 is constituted. Accordingly, the storage space 20 has a hollow shape in which the periphery is surrounded by the outer peripheral wall 10, the bottom surface is closed by the fixed contact metal plate 4, and the upper surface is closed by the exterior metal plate 3 to close the inside.

  The insulating case 2 is formed by insert-molding a part of the fixed contact metal plate 4 on the first outer wall 11A and the intermediate portion 4B of the fixed contact metal plate 4 in the middle of the first outer wall 11A in FIGS. It is fixed. Therefore, the fixed contact metal plate 4 is fixed to the insulating case 2 in a state of penetrating the first outer wall 11A, the portion exposed to the inside of the storage space 20 is set as the fixed contact 5, and the portion drawn out to the outside is the connection terminal 4X. It is said.

  The connection terminal 4X of the fixed contact metal plate 4 is connected to the front end connecting surface (the bottom surface in FIGS. 5 and 6) so that it can be fixed to the surface of the circuit board by soldering such as reflow solder. ) Is bent so as to be positioned substantially in the same plane as the bottom surface of the outer case 1, that is, the bottom surface of the insulating case 2. This breaker is heat-treated in a state where the connection terminals 4X are arranged on the solder surface of the circuit board, and is reflow soldered. However, the breaker can reflow solder the exposed portion 44 on the solder surface of the circuit board by using the exposed portion of the fixed contact metal plate 4 exposed from the bottom surface of the insulating case 2 as the exposed terminal 44. This breaker can be fixed by soldering the exposed terminal 44 of the fixed contact metal plate 4 to the surface of a circuit board or the like without necessarily pulling out the connection terminal 4X from the exterior case 1 to the outside.

  The insulating case 2 fixes the non-movable part 6B of the movable contact metal plate 6 to the second outer wall 11B. In the non-energized type breaker of FIGS. 5 and 6, the non-movable part 6B of the movable contact metal plate 6 is fixed to the upper end surface of the second outer wall 11B. The movable contact metal plate 6 is bonded and fixed to the second outer wall 11B, or sandwiched between the exterior metal plates 3 and fixed to the upper end surface of the second outer wall 11B. In the illustrated exterior case 1, one end of the exterior metal plate 3 is laminated in contact with the non-movable portion 6 </ b> B of the movable contact metal plate 6 and fixed to the insulating case 2. In this structure, since the exterior metal plate 3 is directly laminated and fixed on the movable contact metal plate 6, the whole can be made thinner.

  Further, the insulating case 2 shown in the sectional views of FIGS. 5 to 7 is provided with a storage recess 21 in which the heater 9 is disposed in the storage space 20. The storage recess 21 is in the center of the storage space 20, and the bottom surface thereof is closed by the tip end 4 </ b> A of the fixed contact metal plate 4. The storage recess 21 has an inner shape slightly larger than the outer shape of the heater 9 so that the heater 9 can be inserted therein. The storage recess 21 is provided with a protrusion 14 along the outer peripheral edge. The heater 9 inserted into the storage recess 21 slightly protrudes from the upper surface of the protruding portion 14 and places the bimetal 8 that is curved on the upper surface in a thermally coupled state.

  In the storage space 20, the bottom surface of the storage recess 21 is closed with the fixed contact metal plate 4, and the outer bottom surface of the storage recess 21 is closed with the plastic of the insulating case 2. The insulating case 2 is fixed to the insulating case 2 by insert-molding a fixed contact metal plate 4 on a plastic bottom 13 that closes the bottom of the storage space 20 outside the storage recess 21.

  The exterior metal plate 3 that closes the upper surface of the storage space 20 is fixed to the outer wall 11 of the insulating case 2 at both ends without insert molding. In the non-energized type breaker of FIGS. 4 to 6, both end portions of the outer metal plate 3 are fixed to the upper end surfaces of the first outer wall 11A and the second outer wall 11B. The exterior metal plate 3 is fixed to the insulating case 2 via connecting ribs 15 that are integrally formed on the first outer wall 11A and the second outer wall 11B. 5 and FIG. 7, the connecting rib 15 for connecting the exterior metal plate 3 is provided so as to protrude from the front end surface of the outer wall 11, as indicated by a chain line. The exterior metal plate 3 is provided with through holes 25 that allow the connection ribs 15 to pass therethrough. The connection ribs 15 are inserted into the through holes 25 to fix the exterior metal plate 3 to the insulating case 2. In a state where the connecting rib 15 is inserted into the through-hole 25, the distal end surface of the outer wall 11 of the insulating case 2 is reliably secured by pressing and crushing the distal end of the connecting rib 15 or by ultrasonic vibration. That is, it is fixed to the upper surface. With the above structure, the exterior metal plate 3 can be reliably and easily fixed to the accurate position of the insulating case 2. However, the exterior metal plate can be bonded and fixed to the upper surface, which is the front end surface of the insulating case. The exterior metal plate that is bonded and fixed to the insulating case is also provided with a through hole, a connecting rib that is inserted into the through hole is provided on the outer wall, and the connecting rib is inserted into the through hole so that the fixed position of the insulating case is maintained. Can be fixed securely.

  The exterior metal plate 3 is provided with through holes 25 at the four corners, and the connecting ribs 15 inserted into the respective through holes 25 are provided on the distal end surface of the outer wall 11 of the insulating case 2. 8 shows a cross-sectional view of the first outer wall 11A fixing the exterior metal plate 3, and FIG. 9 shows a cross-sectional view of the second outer wall 11B. The first outer wall 11 </ b> A shown in FIG. 8 protrudes from the upper end surface of the opposing wall 12 provided on both sides of the storage space 20 and is provided with connecting ribs 15. The connecting rib 15 is formed in the shape shown on the right side of the drawing, and in the state inserted into the through hole 25, as shown on the left side, the distal end is crushed to fix the exterior metal plate 3. The first outer wall 11A shown in FIG. 8 is provided with the connecting rib 15 on the upper surface of the opposing wall 12 provided on both sides of the storage space 20, but the first outer wall 11A is taken along the line XX in FIG. At the position shown, as shown in the cross-sectional view of FIG. 10, the exterior metal plate 3 can be fixed by providing a connecting rib 15 on the upper surface of the first outer wall 11A. Furthermore, as shown in the cross-sectional view of FIG. 11, the exterior case 1 is provided with a connecting rib 15 protruding from the upper surface of the opposing wall 12 at the position indicated by the line VII-VII in FIG. It is also possible to provide through holes 25 in the exterior metal plate 3 and fix the intermediate part of the exterior metal plate 3 to the insulating case 2.

  Further, the exterior metal plate 3 shown in the cross-sectional views of FIGS. 7 to 9 is provided with a bent side wall 22 that is bent along the outer surface of the facing wall 12 on both sides, and is opposed to the bent side wall 22. The wall 12 is connected by a locking structure. The exterior metal plate 3 shown in the figure is provided on the bent side wall 22 with a locking projection 16 provided on the bent side wall 22 and the opposing wall 12 so as to protrude outward from the opposing wall 12. It comprises a locking hole 26 that guides and locks the locking projection 16. The locking projection 16 is provided with an inclined surface 16A that gradually protrudes in the insertion direction so that the locking projection 16 can be smoothly guided to the locking hole 26.

  Further, in the locking structure of FIG. 10, a locking piece 27 bent inward is provided at the distal end edge of the bent side wall 22, and the locking recess 17 for guiding the locking piece 27 is provided opposite to the insulating case 2. Provided on the outer surface of the wall 12, the locking piece 27 is guided to the locking recess 17, and the exterior metal plate 3 is fixed to the insulating case 2 with a locking structure.

  Further, the locking structure of FIG. 11 is provided with a locking piece 27 bent inward at the front end edge of the bent side wall 22, and this locking piece 27 is hooked on the bottom surface of the opposing wall 12, 3 is fixed to the insulating case 2 with a locking structure. These locking structures are formed by elastically deforming the bent side wall 22 and connecting it to the insulating case 2 with a locking structure. In the connected state, the locking convexity is generated by the elastic restoring force of the bent side wall 22. The part 16 and the locking piece 27 are held in a position to be hooked on the locking hole 26, the locking recess 17 or the bottom surface.

  Furthermore, the exterior metal plate 3 is provided with an insulating film (not shown) on the surface. This insulating film is provided on the surface of the exterior metal plate 3 by applying an insulating paint. However, the insulating layer can be provided by attaching an insulating sheet to the surface of the exterior metal plate. Thus, the non-energized type breaker in which the exterior metal plate 3 is provided with the insulating film can be insulated from the surface of the exterior metal plate 3 with the insulation film, and can be incorporated in the device in a contact state.

  In the storage space 20 of the insulating case 2, the heater 9, the bimetal 8, and the movable part 6 </ b> A of the movable contact metal plate 6 are stored in order from the bottom, and the fixed contact metal plate is placed on the first outer wall 11 </ b> A of the insulating case 2. 4 is fixed, and the non-movable portion 6B of the movable contact metal plate 6 is fixed to the second outer wall 11B.

  The fixed contact metal plate 4 is fixed to the insulating case 2 by insert molding. The fixed contact metal plate 4 is insert-molded so that the front end portion 4A is embedded in the bottom portion 13 of the storage space 20 and the intermediate portion 4B is embedded from the bottom portion 13 of the storage space 20 to the first outer wall 11A of the insulating case 2. It is fixed to the insulating case 2. The fixed contact metal plate 4 shown in FIGS. 5 and 6 is provided with a step 4D so that a portion embedded in the first outer wall 11A is higher than a portion closing the bottom of the storage recess 21. Is embedded in the bottom portion 13 of the insulating case 2, and the rear end side of the stepped portion 4 </ b> D is exposed on the upper surface of the bottom portion 13, and this exposed portion is used as the fixed contact 5.

  The fixed contact metal plate is a Cu-Cr alloy. The Cu—Cr alloy contains 0.1 mass% or more, preferably 0.2 mass% or more, and 0.5 mass% or less, preferably 0.3 mass% or less of Cr in the base Cu. Further, the Cu—Cr alloy can contain Sn and Zn in addition to Cr. The Sn content is 0.15 mass% or more, preferably 0.23 mass% or more, and is 0.4 mass% or less, preferably 0.27 mass% or less. The Zn content is 0.1 mass% or more, preferably Is 0.18 mass% or more and 0.5 mass% or less, preferably 0.27 mass% or less.

  The above-mentioned fixed contact metal plate can increase the maximum current for switching the contact point to the OFF state by heating the bimetal with the Joule heat of the current flowing through it, and the electrical resistance is optimal for spot welding the lead plate. Can be resistance. For this reason, it is possible to reliably and stably spot weld the lead plate directly to the fixed contact metal plate while preventing the breaker from being switched off by the current. However, the breaker of the present invention does not specify the fixed contact metal plate as a Cu—Cr alloy, and other metal plates that can reduce the heating of the bimetal due to Joule heat due to electric current can be used.

  The heater 9 generates heat when energized and heats the bimetal 8. The heater 9 is a PTC heater having a thickness in which an opposing surface is an oval or a rectangle, and electrodes are provided on the upper surface and the lower surface. However, it is not always necessary to use a PTC heater as the heater, and all heaters that can be energized to heat the bimetal 8 can be used. The heater 9 provided with electrodes on the upper and lower surfaces makes the lower surface contact the fixed contact metal plate 4 and allows the upper surface to contact the movable contact metal plate 6 via the bimetal 8. In the heater 9, when the movable contact 7 of the movable contact metal plate 6 contacts the fixed contact 5, the movable contact metal plate 6 and the bimetal 8 are not in contact with each other and are not energized. In a state in which the movable contact 7 is away from the fixed contact 5 and is in the off state, the bimetal 8 is energized through the bimetal 8 that contacts the movable contact metal plate 6 and the fixed contact metal plate 4 to generate heat, thereby heating the bimetal 8. As shown in FIG. 6, the heated bimetal 8 holds the movable contact 7 in an off state in which the movable contact 7 is separated from the fixed contact 5. This non-energized type breaker holds the movable contact 7 in the OFF state in the state switched to the OFF state, so that it can be safely used for a battery pack. That is, the battery pack is used in an abnormal state and becomes higher than the set temperature, and after the non-energized breaker is switched off, the heater 9 is continuously energized from the battery pack battery and the bimetal 8 is heated. Therefore, the circuit breaker can be maintained in a state of interrupting the current until the battery is discharged without returning to the on state.

  However, the breaker is not necessarily limited to a structure with a built-in heater. Breakers without a built-in heater are deformed when the bimetal becomes higher than the set temperature, and when the contact point is turned off by deforming the movable contact metal plate, the bimetal is heated and the breaker is not held in the off state. When the bimetal is lowered to a predetermined temperature, the bimetal and the movable contact metal plate are restored, and the breaker is turned on.

  The bimetal 8 is formed by laminating metals having different coefficients of thermal expansion so as to be deformed by heating. The bimetal 8 is disposed between the heater 9 and the movable contact metal plate 6 and is deformed so as to be reversed by being heated, so that the movable contact 7 is separated from the fixed contact 5 and the breaker is turned off. In the state where the bimetal 8 is curved in the center convex shape and is not thermally deformed, that is, in the state where the movable contact 7 is brought into contact with the fixed contact 5, as shown in FIG. In a state of projecting to the side and deforming so as to be reversed by thermal deformation, the center projecting portion projects to the heater 9 side as shown in FIG. As shown in FIG. 6, in the state where the bimetal 8 is reversed by thermal deformation, the center protruding portion is brought into contact with the heater 9 and both end portions are brought into contact with the movable contact metal plate 6 and pressed, thereby moving the movable portion 6A. Push up to move the movable contact 7 away from the fixed contact 5 and switch it off.

  As shown in FIGS. 5 and 6, the movable contact metal plate 6 fixes the non-movable part 6 </ b> B, which is an intermediate part, to the upper end surface of the second outer wall 11 </ b> B, and moves the movable part 6 </ b> A on the distal end side of the storage space 20. Arranged inside, the rear end is drawn out of the outer case 1 to form the connection terminal 6X. The movable contact metal plate 6 is fixed to the upper end surface of the second outer wall 11B by bonding the non-movable part 6B. Further, as shown in FIGS. 5, 6, and 9, the movable contact metal plate 6 has a non-movable portion 6B sandwiched between the second outer wall 11B and the exterior metal plate 3, so that the second outer wall 11B It is fixed to the top surface. In the non-energized type breaker shown in the figure, one end portion of the exterior metal plate 3 is laminated in contact with the non-movable portion 6B of the movable contact metal plate 6. Therefore, the exterior metal plate 3 can also be used as a contact point of the movable contact metal plate 6. However, the movable contact metal plate can be laminated while being insulated from the exterior metal plate.

The movable contact metal plate 6 is a metal plate that can elastically deform the movable portion 6A disposed in the storage space 20. The movable contact metal plate 6 is a Cu—Ni—P alloy containing Ni in addition to P. This Cu-Ni-P alloy is used as the base Cu.
0.1 mass% or more, preferably 0.3 mass% or more, more preferably 0.6 mass% or more, 1.6 mass% or less, preferably 1 mass% or less, more preferably 0.8 mass% or less, and Ni 0.05 mass% or more,
Preferably it is 0.1 mass% or more, 0.3 mass% or less, Preferably it contains 0.15 mass% or less P.
Furthermore, the Cu—Ni—P alloy can contain Zn and Fe in addition to P and Ni. This Cu-Ni-P alloy is
0.02 mass% or more, preferably 0.05 mass% or more, 0.5 mass% or less, preferably 0.2 mass% or less, and Zn
It is 0.02 mass% or more, preferably 0.05 mass% or more, and contains 0.3 mass% or less, preferably 0.15 mass% or less of Fe.

  Further, the movable contact metal plate 6 is provided with a movable contact 7 on the surface of the movable portion 6 </ b> A that faces the fixed contact 5. When the bimetal 8 is not thermally deformed, the movable contact metal plate 6 is turned on when the movable contact 7 comes into contact with the fixed contact 5, and when the bimetal 8 is thermally deformed, the movable portion 6A pushed by the bimetal 8 is Due to elastic deformation, the movable contact 7 is separated from the fixed contact 5 and is turned off. The non-energized type breaker shown in FIG. 5 and FIG. 6 presses the rear end portion of the movable portion 6A downward so that the movable contact 7 can be surely brought into contact with the fixed contact 5 without the bimetal 8 being thermally deformed. The pressing convex portion 23 is provided so as to protrude from the inner surface of the exterior metal plate 3. In this movable contact metal plate 6, the rear end portion of the movable portion 6A is pressed downward by the pressing convex portion 23, whereby the distal end portion of the movable portion 6A is urged downward, and the movable contact 7 at the distal end is reliably secured. To the fixed contact 5.

  Further, the movable contact metal plate 6 shown in FIGS. 5 to 7 is provided with a protruding portion 6C on the lower surface, and both ends of the bimetal 8 are brought into contact with the protruding portion 6C and pressed against each other. The projecting portion 6C shown in the drawing has an arc shape, so that both end portions of the bimetal 8 can be reliably brought into contact with each other without being slid in the lateral direction and pressed together. The movable contact metal plate 6 shown in the figure has a plurality of protrusions 6 </ b> C on the lower surface facing both ends of the bimetal 8. In this structure, even the wide bimetal 8 can be brought into contact with each other and pressed together.

  The connection terminal 6X of the movable contact metal plate 6 has a connection surface (bottom surface in FIGS. 5 and 6) at the tip portion that is pulled out from the outer case 1 so that it can be fixed to the circuit board by soldering such as reflow solder. The outer case 1 is bent so as to be positioned substantially in the same plane as the bottom surface of the outer case 1, that is, the bottom surface of the insulating case 2. This breaker is heat-treated in a state where the connection terminals 6X are arranged on the solder surface of the circuit board, and is reflow soldered. However, the breaker laminates the exterior metal plate 3 in contact with the movable contact metal plate 6, and uses the exposed portion of the exterior metal plate 3 electrically connected to the movable contact metal plate 6 as the exposed terminal 43. Can be reflow soldered onto the solder surface of the circuit board. This breaker can connect and fix the movable contact metal plate 6 to the surface of a circuit board or the like via the exterior metal plate 3 without necessarily pulling out the connection terminal 6X of the movable contact metal plate 6 from the exterior case 1 to the outside.

  As shown in FIG. 12, the circuit breaker shown in FIGS. 4 to 6 is a circuit that connects the connection terminals 6X of the movable contact metal plate 6 and the connection terminals 4X of the fixed contact metal plate 4 drawn out from both ends of the outer case 1 to the outside. It is fixed to the substrate 60 by soldering. The breaker is disposed on the circuit board 60 and soldered so that the bottom surface of the outer case 1, that is, the bottom surface of the insulating case 2 faces the upper surface of the circuit board 60. This breaker is heat-treated in a state where the connection terminals 6X and the connection terminals 4X provided at both ends of the outer case 1 are disposed on the solder surface 61 provided on the surface of the circuit board 60, and is reflow soldered. The breaker is connected to the solder surface 61 of the circuit board 60 via the connection terminal 6X and the connection terminal 4X, and is fixed to a fixed position of the circuit board 60.

  Further, the breaker shown in FIG. 13 includes a connection terminal 6X of the movable contact metal plate 6 drawn out from one end of the outer case 1 and an exposed terminal of the fixed contact metal plate 4 exposed from the bottom surface of the insulating case 2. 44 is fixed to the circuit board 60 by soldering. Since this breaker connects the exposed terminal 44 of the fixed contact metal plate 4 to the circuit board 60, the connecting terminal 4X shown in FIG. 5 and FIG. This breaker is also placed on the upper surface of the circuit board 60 and soldered so that the bottom surface of the outer case 1, that is, the bottom surface of the insulating case 2 faces the upper surface of the circuit substrate 60. In this breaker, the connection terminal 6X provided at one end of the outer case 1 and the exposed terminal 44 exposed from the bottom surface of the insulating case 2 are arranged on the solder surface 61 provided on the surface of the circuit board 60. Heat treated and reflow soldered. The breaker is connected to the solder surface 61 of the circuit board 60 via the connection terminal 6 </ b> X and the exposed terminal 44, and is fixed to a fixed position on the circuit board 60.

  Further, the breaker shown in FIG. 14 is an exterior metal plate that is laminated and electrically connected to the connection terminal 4X of the fixed contact metal plate 4 drawn out from one end of the exterior case 1 and the movable contact metal plate 6. 3 and the exposed terminals 43 are fixed to the circuit board 60 by soldering. This breaker is disposed on the upper surface of the circuit board 60 and soldered in a posture in which it is turned upside down from the state shown in FIGS. Therefore, the breaker shown in FIG. 14 has the connection surface (lower surface in FIG. 14) of the connection terminal 4X of the fixed contact metal plate 4 drawn out from the insulating case 2 as the upper surface of the exterior metal plate 3, that is, the exterior metal plate 3. Is bent so as to be substantially flush with the upper surface (the lower surface in FIG. 14). Furthermore, since this breaker connects the exposed terminal 43 of the exterior metal plate 3 to the circuit board 60, the connection terminal 6X shown in FIG. 5 and FIG. This breaker is heat-treated in a state where the connection terminal 4X provided at one end of the exterior case 1 and the exposed terminal 43 of the exterior metal plate 3 are disposed on the solder surface 61 provided on the surface of the circuit board 60, and the reflow solder Is done. The breaker is connected to the solder surface 61 of the circuit board 60 via the connection terminal 4X and the exposed terminal 43, and is fixed to a fixed position on the circuit board 60.

  Further, in the breaker shown in FIGS. 15 to 18, the outer metal plate 3 is fixed to the connecting plastic 52, the connecting plastic 52 is fixed to the insulating case 2, and the outer metal plate 3 is fixed to the insulating case 2. The exterior metal plate 3 is fixed to the connecting plastic 52 by insert molding. The exterior metal plate 3 to be insert-molded is temporarily fixed in a molding chamber of a mold for molding the connecting plastic 52, and molten plastic is injected into the molding chamber and fixed to the connecting plastic 52. The connecting plastic 52 is ultrasonically welded and fixed to the insulating case 2, and the insulating case 2 and the connecting plastic 52 constitute the outer case 1. However, the connecting plastic can be bonded or fixed to the insulating case with a fitting structure. The connecting plastic 52 is fixed to the first outer wall 11 </ b> A and the second outer wall 11 </ b> B provided at both ends of the insulating case 2 around the outer metal plate 3, and further fixed to the opposing wall 12. The exterior metal plate 3 is exposed terminals 43 excluding the outer peripheral portion. As shown in FIGS. 15 to 17, the outer metal plate 3 and the connecting plastic 52 have the same upper surface. This breaker can be connected with the exposed terminal 43 in contact with the solder surface of the circuit board. That is, the connecting plastic 52 protrudes, and the exposed terminal 43 to be connected can be reliably and stably connected to the solder surface without separating the exposed terminal 43 from the solder surface. In order to make the upper surface of the exterior metal plate 3 flush with the connecting plastic 52, a stepped portion 3a that is lowered is provided on the outer peripheral portion of the upper surface, and the connecting plastic 52 is formed on the stepped portion 3a.

  Further, in the breaker shown in FIGS. 15 and 16, one end of the fixed contact metal plate 4 is drawn out of the insulating case 2 to be a connection terminal 4X. The connection terminal 4X of the fixed contact metal plate 4 has an exterior connection surface (upper surface in FIG. 15) that is pulled out from the exterior case 1 so that it can be fixed to the surface of the circuit board by soldering such as reflow solder. The upper surface of the case 1, that is, the upper surface of the exterior metal plate 3 is bent so as to be positioned substantially in the same plane.

As shown in FIG. 19, the breaker is disposed on the upper surface of the circuit board 60 and soldered in a posture in which it is turned upside down from the state shown in FIGS. This breaker includes a connection terminal 4X of the fixed contact metal plate 4 drawn out from one end of the exterior case 1 and an exposed terminal 43 of the exterior metal plate 3 laminated and electrically connected to the movable contact metal plate 6 in a contact state. Are reflow soldered by heat treatment in a state of being disposed on a solder surface 61 provided on the surface of the circuit board 60. The breaker is connected to the solder surface 61 of the circuit board 60 via the connection terminal 4 </ b> X and the exposed terminal 43, and is fixed to a fixed position on the circuit board 60. However, this breaker is also provided with a connection terminal 6X by pulling out one end of the movable contact metal plate 6 to the outside of the exterior case 1 as shown by a chain line in FIG. 16, and the connection terminal 6X of the movable contact metal plate 6 and the fixed contact metal. It is also possible to solder to the solder surface 61 of the circuit board 60 via the connection terminals 4X of the board 4.
[Example]

The movable contact metal plate 6 is made of Cu as a base metal, and a Cu—Ni—P alloy containing Ni and P is used. The fixed contact metal plate is made of Cu as a base metal, and Cr. A breaker having a structure shown in FIGS. 4 to 9 is manufactured using a Cu—Cr alloy containing Cu.
The Cu—Ni—P alloy used for the movable contact metal plate contains the following metals in the base metal Cu.
This Cu—Ni—P alloy has a conductivity of 65% IACS, a volume resistivity of 0.0265 μΩ · m, a thermal conductivity coefficient of 267 W / m · k, and a Young's modulus of 110 GPA.
Ni …… 0.7mass%
P ………… 0.13mass%
Zn …… 0.1mass%
Fe …… 0.1mass%

The Cu-Cr alloy used for the fixed contact metal plate contains the following metals in the base metal Cu.
This Cu—Cr alloy has an electrical conductivity of 65% IACS, a volume resistivity of 0.023 μΩ · m, a thermal conductivity coefficient of 301 W / m · k, and a Young's modulus of 127 GPA.
Cr ………… 0.25mass%
Sn ............ 0.25mass%
Zn ............ 0.22 mass%
[Comparative example]

A breaker having the same structure as in Example 1 was manufactured except that the movable contact metal plate and the fixed contact metal plate were made of phosphor bronze. The phosphor bronze used in Comparative Example 1 contains the following metals in the base metal Cu.
This phosphor bronze has a conductivity of 12% IACS, a volume resistivity of 0.133 μΩ · m, a thermal conductivity coefficient of 67 W / m · k, and a Young's modulus of 110 GPA.
Sn …… 7.0mass%
P ………… 0.2mass%

  The current at which the breakers of the above examples and comparative examples are switched off is measured by the measurement circuit shown in FIG. In the measurement circuit of this figure, a shunt resistor 63 for detecting a current, a breaker, and an electronic load 65 for controlling the current are connected in series to a DC power source 62. The current is measured from the voltage across the shunt resistor 63. The breaker 64 is placed in a constant temperature bath 66 at 60 ° C., and the ambient temperature is maintained at a constant temperature of 60 ° C. The breaker 64 sets the bimetal and the movable contact metal plate so that when the ambient temperature reaches 75 ° C., the bimetal is inverted and switched to the off state. The electronic load 65 increases the breaker current with a slope of 0.2 A / min.

  When the current at which the breaker was switched to the off state was measured with the above measuring apparatus, the breaker of the example was switched to the off state at 7.6 A, and the breaker of the comparative example was switched to the off state at 4.1 A. Therefore, the breaker according to the embodiment of the present invention can be used as a protection element for a battery pack or the like having a maximum current of 7A. On the other hand, the breaker of the comparative example can be used as a protective element only for equipment having a maximum current of 4A.

DESCRIPTION OF SYMBOLS 1 ... Exterior case 2 ... Insulation case 3 ... Exterior metal plate 3a ... Step part 4 ... Fixed contact metal plate 4A ... Tip part
4B ... Intermediate part
4D ... Step part
4X: Connection terminal 5 ... Fixed contact 6 ... Movable contact metal plate 6A ... Movable part
6B ... Non-movable part
6C ... Projection
6X: connection terminal 7 ... movable contact 8 ... bimetal 9 ... heater 10 ... outer peripheral wall 11 ... outer wall 11A ... first outer wall
DESCRIPTION OF SYMBOLS 11B ... 2nd outer wall 12 ... Opposite wall 13 ... Bottom part 14 ... Protrusion part 15 ... Connection rib 16 ... Locking convex part 16A ... Inclined surface 17 ... Locking recessed part 20 ... Storage space 21 ... Storage recessed part 22 ... Bending side wall 23 ... Pressing convex part 25 ... Through hole 26 ... Locking hole 27 ... Locking piece 43 ... Exposed terminal 44 ... Exposed terminal 52 ... Connecting plastic 60 ... Circuit board 61 ... Solder surface 62 ... DC power supply 63 ... Shunt resistor 64 ... Breaker 65 ... Electronic load 66 ... Constant temperature bath 105 ... Fixed contact 106 ... Moving contact metal plate 107 ... Moving contact 108 ... Bimetal

Claims (4)

A fixed contact metal plate (4) having an outer case (1), a fixed contact (5) fixed to the outer case (1), and a fixed contact (5) of the fixed contact metal plate (4). A movable contact metal plate (6) having a movable contact (7) at a position where the movable contact (7) is movable, and a part of the movable contact metal plate (6) fixed to the outer case (1) so that the movable contact (7) can be moved. A bimetal (8) disposed between the plate (6) and the fixed contact metal plate (4), and deformed at an ambient temperature to switch the movable contact metal plate (6) from on to off;
In the state where the bimetal (8) does not press the movable contact metal plate (6), the movable contact (7) is brought into contact with the fixed contact (5) by the elasticity of the movable contact metal plate (6), and is turned on. The bimetal (8) is deformed at ambient temperature, and the deformed bimetal (8) presses the movable contact metal plate (6) to move the movable contact (7) away from the fixed contact (5) to be switched off. A non-energized type breaker for a battery pack ,
The movable contact metal plate (6),
In addition to 0.05 wt% to 0.3 wt% phosphorus,
0.1 wt% or more and 2 wt% or less of nickel;
0.02 wt% or more and 0.5 wt% or less of zinc,
Contains 0.02 wt% or more and 0.5 wt% or less of iron
A non-energized breaker for a battery pack , characterized by being a Cu-Ni-P alloy. The non-energized type breaker for a battery pack according to claim 1 , wherein the fixed contact metal plate (6) is a Cu-Cr alloy containing tin, zinc, and chromium. The non-energized type for a battery pack according to claim 1 or 2 , wherein a heater (9) for heating the bimetal (8) is disposed between the bimetal (8) and the fixed contact metal plate (4). Breaker. The non-energized breaker for a battery pack according to claim 3 , wherein the heater (9) is a PTC heater.

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