WO2013039227A1

WO2013039227A1 - Positive temperature coefficient (ptc) device

Info

Publication number: WO2013039227A1
Application number: PCT/JP2012/073709
Authority: WO
Inventors: 久薄井
Original assignee: タイコエレクトロニクスジャパン合同会社
Priority date: 2011-09-15
Filing date: 2012-09-14
Publication date: 2013-03-21
Also published as: CN103918040B; CN103918040A; JP6124793B2; JPWO2013039227A1; KR20140067107A; KR101892789B1

Abstract

A PTC device, which reduces the potential of an electrical connection of a solder connection formed to be connected to a substrate from becoming defective as much as possible, is provided. The PTC device comprises a PTC element having: a PTC unit comprising a layered PTC component and a first layered electrode and a second layered electrode, which are each positioned on a surface on either side of the layered PTC component; and insulating layers positioned on the outside of each layered electrode. The PTC element has a first end and a second end, and, at the first end, has a first quarter cylindrical recess in each corner, and at the second end, has second quarter cylindrical recesses in the corners. Each first quarter cylindrical recess has a first castellated electrode that is electrically connected to the first layered electrode, and each second quarter cylindrical recess has a second castellated electrode that is electrically connected to the second layered electrode.

Description

PTC device

The present invention relates to a PTC device, and more particularly to a surface mount type PTC device.

For example, a PTC device is used in various electrical devices as a circuit protection element, and constitutes a protection circuit for the electrical device. Such a PTC device is arranged on a protection circuit board having a protection circuit. In that case, a surface mount type PTC device is often used in consideration of arrangement convenience.

The surface mount type PTC device is placed so that its electrode is located on a tab or pad provided on the protection circuit board, and is electrically connected by soldering, thereby forming a protection circuit formed on the protection circuit board. Placed in the circuit.

Such a PTC device is schematically shown in a perspective view in FIG. The illustrated PTC device 10 includes a PTC element 11 constituting the PTC device 10. The PTC element 11 includes a PTC element and layered electrodes respectively disposed on the surfaces on both sides thereof, and an insulating layer positioned outside each layered electrode. In FIG. 1, these components are not shown, but are shown as a PTC element 11.

The PTC element 11 has

semi-cylindrical recess portions

12 and 14 on the side end surfaces at both ends, and a side metal layer portion (for example, a conductive metal plating layer) 16 and the like on the surface of the semi-cylindrical recess portion. 18 On the other hand, the PTC element 11 has end metal layer portions (for example, conductive metal plating layers) 20, 22 and 24, 26 at both ends of the upper surface and the lower surface thereof. The lateral metal layer portions 16 and 18 are integrally connected to the end

metal layer portions

20, 22 and 24, 26 at their upper and lower ends, which constitute so-called castellation electrodes (20 + 16 + 22 and 24 + 18 + 26). ing.

In the illustrated embodiment, the castellation electrode has a metal layer portion on both the upper surface and the lower surface of the PTC element 11, but the castellation electrode is generally connected to both ends of the upper surface and the lower surface of the PTC element. There may be a partial metal layer portion (that is, the end metal layer portion may not be provided at the end of the other surface). Therefore, the castellation electrode has end metal layer portions at both ends of at least one of the upper surface and the lower surface of the PTC device.

Although not shown, in such a PTC device, one castellation electrode is electrically connected to one electrode of a PTC element located in the PTC device, and the other castellation electrode is connected to the other of the PTC elements. Are electrically connected to the electrodes. Such a PTC device is disclosed in Patent Document 1 below, for example.

In mounting such a PTC device on a substrate, cream solder is applied onto a pad provided on the substrate by printing, and castellation located on the lower surface of the PTC device is applied to the pad via the applied cream solder portion. The PTC device is disposed so that the end metal layer portion (for example, 22) of the electrode is positioned, and the substrate on which the PTC device is disposed is placed in a reflow furnace to melt and solidify the solder. A state in which the PTC device is mounted on the substrate by soldering in this manner is schematically shown in FIG. 2 in a sectional view.

FIG. 2 shows an end view of the PTC device 10 of FIG. 1 mounted on the substrate 28, cut along a vertical plane including the line XX. In FIG. 2, only the right end of the PTC device of FIG. 1 is illustrated, and the castellation electrode is exaggerated for easy understanding. A solder connection portion 32 is formed by soldering between the pad 30 on the substrate and the end metal layer portion 22 of the castellation electrode, and these are joined together and electrically connected. Solder melted in the reflow furnace also wets over the semi-cylindrical concave portion, solidifies as it is, and a solder portion 34 is also present as a fillet portion on the side metal layer portion 16 of the castellation electrode, which is a solder connection portion. 32 is integrated.

US Pat. No. 6,377,467

As described above, I noticed the problem that the electrical connection between the PTC device and the substrate becomes poor when the substrate on which the PTC device is soldered is used. More specifically, a part of the solder connection portion 32 may be peeled off between the end metal layer portion 22 and the pad 30, and as a result, the electrical connection between them is insufficient. It was. Therefore, the problem to be solved by the present invention is to reduce as much as possible the possibility of such an electrical connection being defective.

When the above-described substrate having poor electrical connection is examined in detail, cracks are generated in the solder connection portion 32, or the solder connection portion comes from the end metal layer portion 22 and / or the side metal layer portion 16. It was found that a part of the solder connection portion 32 was peeled off.

Further examination of this phenomenon reveals that when the PTC device operates, the temperature rises and the PTC element expands, and then the temperature of the PTC element decreases and contracts to return to its original shape.・ It goes through a process called contraction. In addition, when the environment of the electric device having the substrate (for example, the interior of an automobile) repeatedly increases and decreases in temperature, the PTC element repeats the process of expansion and contraction.

When the PTC element repeatedly expands and contracts, a stress is generated due to the volume change, and this results in a large possibility of causing cracks and peeling. In particular, when the PTC device has a semi-cylindrical concave portion on the side as described above, the stress caused by expansion / contraction tends to concentrate on the portion, and as a result, a phenomenon such as crack / peeling is likely to occur. It came to the judgment. Therefore, by reducing the concentration of stress in such a way, more specifically, by increasing the number of locations where stress can be concentrated, reducing the total amount of stress concentrated at each such location. As a result, the inventors have thought that it is possible to suppress the occurrence of cracks, separation, etc., and to reduce the possibility of occurrence of poor electrical connection.

Based on the above-mentioned idea, the inventor has intensively studied about the suppression of stress concentration, and as a result, places where stress may concentrate are not provided in two places on both sides of the PTC device, It has been thought that by using the corner portions of the PTC device, that is, by providing them at four locations, the possibility of poor electrical connection is reduced.

Accordingly, in a first aspect, the present invention provides a PTC device,
This PTC device
A PTC unit comprising a layered PTC element and a first layered electrode and a second layered electrode respectively disposed on the surfaces of the layered PTC element, and an insulation located outside each layered electrode (ie outside the PTC unit) Comprising a (layered) PTC element having a layer,
The PTC element has a first end and a second end, the first end has a first quarter cylindrical recess at each corner, and the second end Having a second quarter cylindrical recess in the corner,
Each first quarter cylindrical recess has a first castellation electrode electrically connected to the first layered electrode, and each second quarter cylindrical recess is connected to the second layered electrode It has the 2nd castellation electrode.

In one aspect, the PTC device further includes the previously described semi-cylindrical recesses at the first end and the second end in addition to the first quarter-cylindrical recess and the second quadrant-cylindrical recess. You can do it.

In the PTC device according to the first aspect described above, in one preferred embodiment, a plurality of PTC units each including a PTC element and layered electrodes disposed on the surfaces on both sides thereof are laminated via an insulating layer. Also good.

That is, in the second aspect, the present invention provides another PTC device,
This PTC device
A plurality of PTC units having a plurality of layered PTC elements, a plurality of PTC units each having a first layered electrode and a second layered electrode disposed on both sides of each PTC element, and the PTC units being spaced apart And having a PTC element as a laminate in which insulating layers arranged between PTC units are laminated,
The PTC element has a first end and a second end,
The PTC element has a first quarter cylindrical recess at each corner portion at the first end and a second quarter cylindrical recess at the corner portion at the second end. ,
Each first quarter cylindrical recess has a first castellation electrode electrically connected to the first layered electrode of each PTC element, and each second quarter cylindrical recess has a second layered electrode And a second castellation electrode connected to the first electrode.

In one aspect, the PTC device includes the semi-cylinder described above at the first end and the second end of the PTC element stack in addition to the first quarter cylindrical recess and the second quarter cylindrical recess. You may further have a shape-like recessed part.

In the PTC device of the present invention, the corner portion of the PTC element or the PTC element laminate has a quarter-cylindrical concave portion, and the castellation electrode is arranged in that portion. Since there are at least four locations where concentration is likely to occur, as a result, the total amount of stress acting on each castellation electrode can be reduced, so that the solder connection portion that functions for electrical connection with the PTC device It is possible to reduce as much as possible the possibility of poor electrical connection.

FIG. 1 schematically shows a perspective view of a conventional PTC device. FIG. 2 schematically shows a state in which a conventional PTC device is mounted on a substrate. FIG. 3 schematically shows a plan view of the PTC device of the present invention. FIG. 4 schematically shows a plan view of another embodiment of the PTC device of the present invention. FIG. 5 schematically shows a cross section (along line YY in FIG. 4) of a PTC device of the present invention having a single PTC unit. FIG. 6 schematically shows a cross section (along line YY in FIG. 4) of a PTC device of the present invention having a plurality of PTC units. FIG. 7 schematically shows a perspective view of the PTC device of the present invention shown in FIG. FIG. 8 schematically shows a plan view of the pressure-bonded body in order to explain the method for producing the PTC device of the present invention.

When mounting the PTC device of the present invention on a substrate, a plan view of the case where the PTC device is placed so that the surface facing the substrate faces upward (corresponding to the case viewed in the direction of arrow A in FIG. 1) is shown. 3 and a perspective view are schematically shown in FIG. Accordingly, the lower surface 38 of the PTC device of FIGS. 1 and 2 becomes the upper surface 38 in FIGS. In the illustrated embodiment, the PTC device 10 includes a PTC element 11, and the PTC element includes a first end 42 and a second end 44.

The PTC element includes a first quarter cylindrical recess (see FIG. 3) 36 or a first quarter cylindrical recess (see FIG. 7), and a second quarter cylindrical recess (see FIG. 3) 37 or second. A quarter-cylindrical recess (see FIG. 7) 37 is cut out as a whole (ie, when there is no cut-out portion), and has a rectangular shape in the plan view of FIG. 3, and a rectangular parallelepiped in the perspective view of FIG. Has a shape. The quarter-circular portions (or quarter-cylindrical concave portions) 36 and 37 are derived from the fact that the PTC element 10 constituting the PTC device has the quarter-cylindrical concave portions as notches at four corner portions.

More specifically, the PTC element 11 has two first quarter cylindrical portions 36 at the first end portion 42 and two first quarter cylindrical portions 37 at the second end portion 44. . In another aspect, there may be a semi-cylindrical recess 12 as shown in FIG. 1 between the two first or second quadrants 36 and / or 37.

In addition, it is particularly preferable that the quarter-cylindrical recess 36 has a quarter shape of the cylinder (thus, in FIG. 3, a quarter-circle shape). However, the PTC element 11 may have another cutout shape instead of the quadrant shape as long as the four corner portions are cut out. In the plan view, the cutout shape may be a right triangle shape or a quarter ellipse shape.

The illustrated PTC device 10 has a side metal layer portion 16 on a side surface 40 defining each first quarter cylindrical recess 36 of the PTC element 11, and one end portion of the side surface (the embodiment shown in FIG. 7). The upper end 46) has the end metal plating layer portion 22, and these metal layer portions are integrally connected to form the first castellation electrode 50. The PTC device 10 has a side metal layer portion 17 on a side surface 41 that defines each second quarter cylindrical recess 37 of the PTC element 11, and one end portion of the side surface (the mode shown in FIG. 7). Then, the upper end 47) has the end metal layer portion 23, and these metal layer portions are connected together to form the second castellation electrode 52.

The lateral metal layer of the castellation electrode extends over the entire side surface defining the recess, and the end metal layer portions 22 and / or 23 may be annular as shown in FIG. In an aspect, as shown in FIG. 4, it may be rectangular (however, it has a notch corresponding to a quarter circle).

Note that the side surface 40 and / or the side surface 41 has the end metal layer portion 20 (in FIG. 7, for example, the front side is indicated by a broken line at the other end (lower end 48 in the embodiment shown in FIG. 7). These three metal layer portions (ie, the end

metal layer portion

22 or 23 on one end 46, the side

metal layer portion

16 or 17 on the side, and the other end). The end metal layer portion 20) on the portion 48 may constitute first and / or second castellation electrodes. Although not shown, the first castellation electrode 50 is electrically connected to a first layered electrode disposed on the main surface of one or more PTC elements constituting the PTC element, and the second castellation The electrode 52 is electrically connected to a second layered electrode disposed on the main surface of one or more PTC elements constituting the PTC element.

Note that the entire castellation electrode may be formed by plating with a conductive metal. In that case, the castellation electrode can be formed by masking the portion other than the portion where the castellation electrode is to be formed, plating a conductive metal (eg, copper, nickel, tin, etc.), and then removing the masking. In this case, each of the side metal layer portion and the end metal layer portion is constituted by a plating layer.

In another aspect, the end metal layer portion may be a metal foil and a plating layer formed thereon. In this case, as will be described later, after forming a pressure-bonded body in which a metal foil is stacked on an insulating resin sheet for forming an insulating layer as an outermost layer of the PTC element, and leaving a metal foil at a predetermined position by etching, a plating process is performed. By doing so, such an end metal layer portion can be formed. Also in this aspect, the side metal layer portion is constituted by a plating layer.

Furthermore, in another aspect, the metal having excellent corrosion resistance is formed on the outermost layer of the castellation electrode formed by the plated layer or the castellation electrode formed by the metal foil and the plated layer formed thereon as described above. The layer may be further formed by a plating process. For example, when the outermost layer is made of copper, it is preferable to overlay a nickel and then tin plating layer or a nickel and then gold plating layer thereon.

FIG. 5 schematically shows a cross section that appears when the PTC device of the present invention is cut along line YY in FIG. The illustrated PTC element 10 includes a PTC unit 60 having a layered PTC element 54 and a first layered electrode 56 and a second layered electrode 58 disposed on the surfaces of the layered PTC element 54, and outside the layered electrodes ( In other words, the PTC element 66 is formed as a whole having the first insulating layer 62 and the second insulating layer 64 positioned outside the PTC unit. The PTC element 66 has a first end portion 42 and a second end portion. At the first end portion, the PTC element 66 has a first quarter cylindrical recess 36 at each corner portion thereof, and at the second end portion. In addition, a second quarter cylindrical recess 37 is provided at the corner.

Note that a PTC unit having a layered PTC element, a layered electrode (usually a metal foil) located on both sides of the layered PTC element, and an insulating layer is a well-known member, and is described in detail, for example, in the above-mentioned patent document. Is omitted.

As shown in the figure, a first castellation electrode 50 electrically connected to the first layered electrode 56 at its end 68 is formed on the side surface 40 defining the first quarter cylindrical recess, A second castellation electrode 52 electrically connected to the second layered electrode 58 at its end 70 is formed on the side surface 41 that defines each second quadrant cylindrical recess 37.

As can be readily appreciated, in the illustrated embodiment, each castellation electrode is located at each end of the side metal layer portion 72 (corresponding to 16 or 18 in FIG. 1) and the top and bottom surfaces of the PTC element 66, respectively. End metal layer portions 74 (corresponding to 20 or 24 in FIG. 1) and 76 (corresponding to 22 or 26 in FIG. 1). Such a metal layer portion is preferably a metal plating layer from the viewpoint of efficient production as described later.

FIG. 6 schematically shows a cross section that appears when a PTC device according to another aspect of the present invention is cut in the same manner as in FIG. In the illustrated embodiment, as an example, it has two layered PTC elements 78 and 80, and a first

layered electrode

82 and 84 and a second layered electrode 86 and 88 respectively disposed on the surfaces on both sides of each PTC element. And two

PTC units

90 and 92. These PTC units are sandwiched between insulating

layers

94, 96 and 98 so that the insulating layers are located on both sides of the PTC units, and are disposed between them. These insulating layers and the PTC units disposed therebetween are laminated to form a PTC element as a laminate.

Similar to the embodiment of FIG. 5, the PTC element has a first end 42 and a second end 44 at the first quarter cylindrical portion 36 and the second quarter cylindrical portion. 37, and a first castellation electrode 50 and a second castellation electrode 52 are formed on the side surface defining these. In the illustrated embodiment, the first

layered electrodes

82 and 84 are electrically connected to the first castellation electrode 50 at their ends, and the second layered electrodes 86 and 88 are electrically connected to the second castellation electrode 52. Connected.

In the embodiment shown in FIG. 6, two PTC units are laminated, but more PTC units may be laminated so that the PTC units are sandwiched between insulating layers. In this case, one layered electrode of each PTC unit is connected to the first castellation electrode, and the other layered electrode is connected to the second castellation electrode, whereby the PTC units are connected in parallel. The device can be configured.

For example, the PTC device of the present invention can be manufactured as follows. First, a main layer on both sides of a polymer PTC sheet obtained by extruding a polymer PTC composition is pressure-bonded to a metal layer (for example, a metal foil) constituting a layered electrode, or a polymer PTC composition And a metal layer are coextruded to obtain a laminate in which the PTC sheet is sandwiched between the metal layers. Next, the obtained laminate is subjected to an etching process to remove a part of the metal layer (a part corresponding to the part 100 in FIG. 5 or FIG. 6), and then an insulating layer is formed on both sides. Insulating resin sheets (for example, prepreg sheets) are stacked, and conductive metal foils (for example, copper foils) are stacked on the outside as necessary, and these are integrally pressed to obtain a pressed body.

Then, as shown in FIG. 8, drilling is performed so that a cylindrical hole is formed at a predetermined position of the crimping body. Then, the entire punched crimped body is subjected to copper plating in a lump, and thereafter, only the portions corresponding to the end metal layer portions on the upper surface and the lower surface and the cylindrical recess formed by drilling are masked. Etch the metal part. Thereafter, the masking is removed, and four

portions

22 or 23 corresponding to the end metal layer portions on the upper surface and the lower surface (rectangles obtained by cutting out the 90 ° fan-shaped portion 104) are defined and defined. Two larger rectangular plating layers 106 and plating layers on the sides of the cylindrical recess formed by drilling are formed. FIG. 8 is a schematic plan view showing the crimp body 102 formed as described above. In addition, although the part corresponding to the edge part

metal layer part

22 or 23 of the upper surface and lower surface formed in this way is comprised by copper foil and the copper plating layer formed on it, for example, FIG. In FIG. 6 and FIG. 7, these are shown as an integrated object. Thereafter, the pressure-bonded body 102 may be subjected to a metal plating process (for example, a nickel or tin plating process) as necessary.

By drilling, the thickness portion of the layered metal disposed on the PTC element is exposed on the side surface portion of the cylindrical recess, and such side surface portion is plated so that the castellation electrode is formed on the side surface. Since the side metal plating layer is formed, the end portion of the layer metal is electrically connected to the side metal plating layer.

The individual PTC devices 10 of the present invention can be obtained by cutting the pressure-bonded body 102 thus plated, along the dividing line 110 in the vertical direction and the dividing line 112 in the horizontal direction. Thus, a PTC device can be efficiently manufactured by forming the press-bonded body in a state where the PTC devices are adjacent to each other in the vertical and horizontal directions, and then dividing them.

Except for forming a quarter-cylindrical recess at a predetermined location of the PTC element, the layered structure of the PTC element as shown in FIGS. A method of manufacturing a PTC device having a structure in which an electrode is electrically connected to a castellation electrode is basically known, and can be referred to, for example, Patent Document 1 described above.

The PTC device of the present invention is particularly effective when the PTC element is hard. That is, when the conductive polymer composition constituting the PTC element includes a relatively hard polymer, for example, when it includes polyvinylidene fluoride resin (PVDF), compared to a softer resin (for example, polyethylene), PTC Since it is difficult to relieve the stress generated by the expansion / contraction of the element, it is effective to provide a quarter cylindrical recess in the PTC device and form a castellation electrode there.

10 ... PTC device, 11 ... PTC element, 12, 14 ... Semi-cylindrical concave portion,
16, 18 ... Side metal layer portion, 20, 22, 24, 26 ... End metal layer portion, 28 ... Substrate,
30 ... Pad, 32 ... Solder connection part, 34 ... Solder part, 36 ... First quarter cylindrical recess,
37 ... 2nd quarter cylindrical recessed part, 40, 41 ... Side surface, 42 ... 1st edge part, 44 ... 2nd edge part,
46 ... one end, 48 ... the other end, 50 ... the first castellation electrode,
52 ... second castellation electrode, 54 ... layered PTC element, 56 ... first layer electrode,
58 ... second layered electrode, 60 ... PTC unit, 62 ... first insulating layer, 64 ... second insulating layer,
66 ... PTC element, 68 ... end of the first layered electrode, 70 ... end of the second layered electrode,
72 ... side metal layer part, 74, 76 ... end metal layer part, 78, 80 ... layered PTC element,
82, 84 ... first layered electrode, 86, 88 ... second layered electrode, 90, 92 ... PTC unit,
94, 96, 98 ... insulating layer, 100 ... part of the metal layer, 102 ... pressure-bonded body,
104 ... Fan-shaped part, 106 ... Larger rectangular plating layer.

Claims

A PTC unit having a layered PTC element and a first layered electrode and a second layered electrode respectively disposed on the surfaces of the layered PTC element, and a PTC element having an insulating layer positioned outside each layered electrode A PTC device comprising:
The PTC element has a first end and a second end, the first end has a first quarter cylindrical recess at each corner, and the second end Having a second quarter cylindrical recess in the corner,
Each first quarter cylindrical recess has a first castellation electrode electrically connected to the first layered electrode, and each second quarter cylindrical recess is connected to the second layered electrode A PTC device comprising a second castellation electrode.
A plurality of PTC units having a plurality of layered PTC elements, a plurality of PTC units each having a first layered electrode and a second layered electrode disposed on both sides of each PTC element, and the PTC units being spaced apart And having a PTC element as a laminate in which insulating layers arranged between PTC units are laminated,
The PTC element has a first end and a second end,
The PTC element has a first quarter cylindrical recess at each corner portion at the first end and a second quarter cylindrical recess at the corner portion at the second end. ,
Each first quarter cylindrical recess has a first castellation electrode electrically connected to the first layered electrode of each PTC element, and each second quarter cylindrical recess has a second layered electrode And a second castellation electrode connected to the PTC device.
Each castellation electrode has a side metal layer portion formed on a side surface defining a quarter-cylindrical concave portion and an end metal layer portion extending on an end portion of one main surface of the PTC element. The PTC device according to claim 1, wherein:
The PTC device according to claim 3, wherein the end metal layer portion includes a metal foil portion and a metal plating layer portion formed thereon.
5. The PTC device according to claim 3, wherein the side metal layer portion is formed of a metal plating layer.
The PTC device according to any one of claims 1 to 5, wherein the layered PTC element is formed of a conductive polymer composition containing polyvinylidene fluoride.