KR102232139B1 - Protection element for high current - Google Patents

Abstract

The present invention relates to a small high current protection device of a surface mount device (SMD) type having a structure capable of improving rated current characteristics without increasing the size of the protection device, which includes: an insulated substrate; a first fuse-connecting electrode and a second fuse-connecting electrode; a fusible body; a first lower connecting electrode and a second lower connecting electrode; and a protective cap. According to the present invention, it is possible to increase the cross-sectional area through which the current flows, and there is an effect that the rated current can be greatly improved without increasing the size of the small SMD type protective device.

Description

High current protection device {PROTECTION ELEMENT FOR HIGH CURRENT}

The present invention relates to a high current protection device, and more particularly, a new high current protection device having a structure capable of improving the rated current characteristics without increasing the size of the protection device in a small protection device of the SMD (Surface Mount Device) type. It is about.

In general, a fuse is a protection device having a characteristic of blocking overcurrent in an electrical circuit and being blown by overcurrent. In various electric circuits, in particular, protection devices are used in secondary battery protection circuits.

The protection device that was conventionally manufactured in the DIP type has recently been replaced by the SMD (Surface Mount Device) type. The SMD type protection device is advantageous in making the component size smaller because of its higher degree of integration compared to the DIP type. In addition, the SMD type protection device has the advantage that it can be applied with high compatibility in various industries using a printed circuit board (PCB). For example, SMD-type protection devices are applied to many home appliances such as TVs as well as products that have recently grown rapidly in the market such as smartphones, tablets, notebooks, and desktop PCs.

1 is an exploded perspective view illustrating a conventional SMD-type small protection device, and FIG. 2 is a perspective view illustrating a state in which the components of FIG. 1 are assembled.

Referring to FIG. 1, in a conventional SMD type small protection device, a first fusible element connection electrode 22 and a second fusible element connection electrode 24 are spaced apart from each other on an insulating substrate 10, and two A soluble body 30 is stacked as a conductor connecting the electrodes. A first lower connection electrode 42 and a second lower connection electrode 44 for mounting on a printed circuit board (PCB) are disposed under the insulating substrate 10, and the first lower connection electrode 42 is an insulating substrate. The second lower connection electrode 44 is bent upward along one side wall of (10) and connected to the first fusible body connection electrode 22, and the second lower connection electrode 44 is bent upward along the other side wall of the insulating substrate 10 It is connected to the soluble body connection electrode 24. And a protective cap 50 for protecting the components is combined at the top.

The protection device of FIG. 1 is installed on the current path of the printed circuit board, and the first lower connection electrode 42, the first soluble body connection electrode 22, the soluble body 30, and the second soluble body connection electrode 24 , When an overcurrent is applied along a conductive line formed in the order of the second lower connection electrode 44 (or in the opposite order), the fusible material 30 is melted to block the current path of the printed circuit board. Perform the action.

However, the flow of current must be maintained smoothly within the rated current, not the overcurrent, but there is a limit to increasing the allowable current when the standard of a small protection device is determined. For example, in the case of a small protection device with a length of 9.5mm, a width of 5mm, and a height of 2mm, the rated current is only about 10A.

The easiest way to improve the rated current of the protection element is to increase the size of the fusible element. However, portable electric products are gradually being designed to be compact, and the market wants a protection device having a high rated current even in a small size. For example, if the rated current characteristic of 30A or more is exhibited in the standard of the exemplified protection device, it will have a very large market competitiveness.

Korean Patent Registration No. 10-1342501 (Surface mount type micro-conductor pattern structure for fuse) Korean Patent Registration No. 10-1409909 (Low temperature/dry conductive paste and SMD micro-fuse manufacturing method using it)

The present invention aims at a compact size of a small SMD type protection device, and an object thereof is to provide a high current protection device of a new structure capable of improving the rated current without increasing the size of the protection device.

In the high current protection device according to an embodiment of the present invention, in a surface mount device (SMD) type protection device, a plurality of substrate via holes penetrating up and down along the longitudinal directions of both sides of a long side portion are formed, and the via holes are respectively formed on both side walls. An insulating substrate having a plurality of substrate cascades concave inwardly formed therebetween; A plurality of electrode cascades disposed to be spaced apart from each other on the upper surface of the insulating substrate, each electrode via hole formed in communication with the substrate via hole along a length direction, and concave inward at a position corresponding to the substrate cascade A first fusible element connecting electrode and a second fusible element connecting electrode which are additionally formed; A fusible element that connects the first fusible element connection electrode and the second fusible element connection electrode and melts at a melting current or higher; They are disposed to be spaced apart from each other on the lower surface of the insulating substrate, respectively, through the substrate via hole along the length direction, and connected to the electrode via hole, and a via in which a conductor is charged is vertically installed, and the substrate cascade at the end thereof. A first lower connection electrode and a second lower connection electrode bent upward to correspond to a portion and on which a vertically curved terminal wall connected to the electrode cascade is installed; And a protective cap coupled to an upper portion of the insulating substrate to protect the fusible material.

In the high-current protection device according to another embodiment of the present invention, three to five via holes are formed in each of the substrate via holes along the length directions of both sides of the insulating substrate, and the substrate castration portion is formed on both side walls of the insulating substrate. To four are formed.

In the high current protection device according to another embodiment of the present invention, the protective cap is configured to form a space in which the upper surface is sealed and the lower surface is recessed toward the upper side to form a space for accommodating the fusible body, and each sidewall of the long side is cut toward the upper side. It has a ventilated long groove.

In the high current protection device according to another embodiment of the present invention, the protection cap further includes a ventilating short groove cut upwardly in each of the front wall and the rear wall of the short side portion.

In the high current protection device according to another embodiment of the present invention, the protection cap further includes a heat induction surface portion concave in the longitudinal direction on each of the front wall and the rear wall.

In the high current protection device according to another embodiment of the present invention, the heat induction surface portion is formed by a first heat induction surface portion extending from the ventilation end groove portion, and a stepped portion protruding toward each other from the front wall and the rear wall. The second heat guide surface portion having a narrower width than the first heat guide surface portion is formed to be divided in the form of an upper narrow light.

According to the high current protection device of the present invention, by forming a plurality of vias (for example, 3 to 5) connected to the fusible element connection electrode through the insulating substrate in the lower connection electrode mounted on the printed circuit board, A curvature terminal wall that secures an additional current path passing through the configured insulating substrate, and is vertically installed along a plurality of cation parts (for example, two to four) formed on the insulating substrate at the lower connection electrode By forming the sectional area through which the current flows can be increased, there is an effect that the rated current can be greatly improved without increasing the size of the SMD type small protection device.

In addition, according to the high current protection device of the present invention, a ventilation long groove is formed in the long side of the protective cap to allow external air to pass in the width direction of the protection element, and a ventilation short groove is formed on the short side of the protective cap to allow external air in the length direction. In order to increase the heat dissipation effect in the relatively narrow ventilated end groove, the heat induction surface in the form of upper and lower light is formed to promote the effect of spreading heat inside the protective cap to the outside. , There is an effect of preventing the melting of the lower surface of the protective cap due to heat generated by high current.

1 is an exploded perspective view illustrating a conventional SMD type small protection device,
2 is a perspective view illustrating a state in which the components of FIG. 1 are assembled;
3 is an exploded perspective view illustrating a high current protection device according to the present invention,
4 is an exploded perspective view illustrating a state in which the high current protection device of the present invention is partially coupled, and
Figure 5 is a rear perspective view illustrating the internal structure of the protective cap in the present invention.

Hereinafter, specific embodiments according to the present invention will be described with reference to the accompanying drawings. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Throughout the specification, parts having similar configurations and operations are denoted by the same reference numerals. In addition, the drawings attached to the present invention are for convenience of description, and the shape and relative scale may be exaggerated or omitted.

In describing the embodiments in detail, overlapping descriptions or descriptions of technologies that are obvious in the art have been omitted. In addition, in the following description, when a certain part "includes" other components, it means that components may be further included in addition to the described components unless otherwise stated.

Terms including ordinal numbers such as first and second may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, the second element may be referred to as the first element, and similarly, the first element may be referred to as the second element.

The high current protection device of the present invention is a compact SMD (Surface Mount Device) type that can be applied with high compatibility to various electrical products (e.g., smartphones, tablets, notebooks, desktop PCs, TVs, etc.) using a printed circuit board (PCB). In the protection device, it relates to a high current protection device that improves the rated current without increasing the size. In the following description, the protection element described with reference to the drawings is provided in, for example, a length of 9.5 mm, a width of 5 mm, and a height of 2 mm. While the small protection device of such a standard has a conventional rated current of 10A, the present invention proposes a structure capable of improving the rated current from 30A to 60A in the same standard. Of course, as the illustrated standard increases or decreases, the rated current may also increase or decrease. In addition, the high current protection device of the present invention is concerned that the melting of the protection cap may occur as the rated current is increased while maintaining a small size, and thus a structure of a protection cap to prevent this is further proposed. A specific embodiment of the present invention will be described with reference to FIGS. 3 to 5.

3 is an exploded perspective view illustrating a high current protection device according to the present invention, and FIG. 4 is an exploded perspective view illustrating a state in which the high current protection device of the present invention is partially coupled.

3, the high current protection device of the present invention includes an insulating substrate 100, a first fusible element connection electrode 110, a second fusible element connection electrode 120, a fusible element 130, and a first It includes a lower connection electrode 140, a second lower connection electrode 150, and a protective cap 160.

The insulating substrate 100 is an insulating member formed of a material such as ceramic. The insulating substrate 100 may be provided with a length of 9.5 mm and a width of 5 mm. In the following description, the term'long side portion' means a longer side of the insulating substrate 100, that is, a side corresponding to the length of the standard. In addition, the term'short side portion' means a shorter side of the insulating substrate 100, that is, a side corresponding to the width of the standard.

Referring to FIG. 3, a plurality of (eg, 3 to 5) substrate via holes 102 and 106 are formed on both sides along the length direction of the long side of the insulating substrate 100. In the illustrated embodiment, the first substrate via holes 102 formed along the long side of the insulating substrate 100 are all five, and each of the first substrate via holes 102 may have a diameter of about 1 mm. A second substrate via hole 106 is formed along the other long side of the insulating substrate 100 so as to be symmetrical with the first substrate via hole 102.

In addition, a plurality of (for example, two to four) first substrate casting units 104 concave to have a predetermined curvature inward between the via holes 102 of the first substrate on one side wall of the insulating substrate 100 Is formed. In the illustrated embodiment, there are four first substrate casters 104. Four second substrate casting units 108 are formed on the other side wall of the insulating substrate 100 so as to be symmetrical with the first substrate casting unit 104.

3, the first fusible element connection electrode 110 and the second fusible element connection electrode 120 are spaced apart from each other on the upper surface of the insulating substrate 100, and the fusible element 130 is stacked to connect the two electrodes. do. The fusible body 130 is composed of a material that melts above the melting current.

As illustrated, the first fusible element connection electrode 110 includes five first electrode via holes 112 along the length direction so as to communicate with the first substrate via hole 102. In addition, at the outer end of the first fusible element connection electrode 110, four first electrode cascades concave inward to have a position and shape corresponding to the first substrate cascade 104 of the insulating substrate 100. A portion 114 is formed. The second fusible element connection electrode 120 also includes five second electrode via holes 122 and four second electrode cascades 124 so as to be symmetric with the first fusible element connection electrode 110.

Referring to FIG. 3, a first lower connection electrode 140 and a second lower connection electrode 150 are spaced apart from the lower surface of the insulating substrate 100. These two electrodes are electrodes for mounting the protection device on a printed circuit board (PCB), and in the protection device, the first lower connection electrode 140 is connected to the first fusible body connection electrode 110, and the second lower connection The electrode 150 is connected to the second fusible element connection electrode 120.

The first lower connection electrode 140 includes five first vias 142 vertically installed to pass through the first substrate via hole 102 and upward from the outer end to correspond to the first substrate casting unit 108. It includes four first vertically curved terminal walls 144 that are bent in a direction. The first via 142 has a cylindrical shape, and a silver (Ag) paste is filled inside the first via 142 to electrically connect the first lower connection electrode 140 and the first fusible body connection electrode 110 Let it. In the illustrated example, since a total of five first vias 142 are formed, five new current paths may be generated for the insulating substrate 100.

The first vertical curvature terminal wall 144 is connected to the first electrode casting unit 124 of the first fusible element connection electrode 110 at the upper end. For example, the first vertical curvature terminal wall 144 and the first electrode casting unit 124 may be connected by soldering or the like. In the illustrated example, since a total of four first vertically curved terminal walls 144 are formed to be concave inward, a cross-sectional area through which current flows can be increased.

Referring to FIG. 3, the second lower connection electrode 150 has a shape symmetrical to the first lower connection electrode 140, and the second via 152 is symmetrical to the first via 142 and has a second vertical curvature. The terminal wall 154 is symmetrical with the first vertically curved terminal wall 144. Accordingly, five new current paths are added to the insulating substrate 100 by the second via 152 and the cross-sectional area through which current flows is added by the second vertically curved terminal wall 154 is also the same.

The protective cap 160 is configured such that the upper surface is sealed and the lower surface is recessed toward the upper side to form a space for accommodating the fusible body 130. As shown in FIG. 3, a ventilation long groove 162 and 164 cut upward is formed in each of the sidewalls of the long side of the protective cap 160, and a ventilation end cut toward the upper side of the front wall and the rear wall of the short side, respectively. Grooves 166 and 168 are formed. Description of these configurations will be described later in detail with reference to FIG. 5.

Figure 5 is a rear perspective view illustrating the internal structure of the protective cap in the present invention, showing the protective cap 160 illustrated in Figure 3 rotated 180 degrees.

The high current protection device of the present invention is designed to withstand a high rated current with a small size. For example, when a conventional small SMD type protection device has a standard of 9.5mm in length, 5mm in width, and 2mm in height, if the rated current of 10A is the limit, the high current protection device of the present invention has a rated current characteristic of 30A to 60A in the same standard. Have. By forming three vias in each lower connection electrode and two vertically curved terminal walls, it may have a rated current characteristic of approximately 30A. As the number of vias and vertically curved terminal walls increases, the cross-sectional area in which the current path is formed increases, and the rated current becomes higher. For example, as illustrated in FIG. 3, as five vias and four vertically curved terminal walls are formed on each lower connection electrode, a cross-sectional area of a copper wire capable of applying 60A can be configured to have a current path cross-sectional area of 5.5 mm2 or more. So, the rated current can be improved up to 60A.

The problem is that the high current protection device of the present invention allows a high rated current in a small size, and heat generation occurs due to a high current due to a trade off phenomenon, and a phenomenon that the protective cap 160, which is most vulnerable to heat, melts within the rated current may occur. Is that there is.

In the present invention, by forming ventilation grooves on each of the four sides of the protective cap 160, it provides a solution to this. As shown by the thick arrow in FIG. 5, the ventilation long grooves 162 and 164 pass outside air in the width direction. And, as shown by a thin arrow in Fig. 5, the ventilation end grooves 166 and 168 pass outside air in the longitudinal direction. Through this ventilation structure, heat inside the protection device can be quickly released to the outside.

Here, since the short side portion of the protection element is smaller than the long side portion, heat dissipation in the longitudinal direction may not be made quickly, and the present invention provides a structure for solving this. Referring to FIG. 5, heat induction surface portions 174, 176, 184, and 186 that are concave inward in the longitudinal direction are formed on the front wall and the rear wall of the short side portion of the protective cap 160, respectively.

Since the structure of the front wall and the rear wall of the short side portion of the protective cap 160 is symmetric, it will be described with reference to the heat induction surface portions 184 and 186 of the front wall illustrated in FIG. 5. The heat induction surface portions 184 and 186 may have a structure in which the first heat induction surface portion 184 and the second heat induction surface portion 186 are spatially partitioned by the stepped portion 182. The first heat guide surface portion 184 is formed as a concave surface extending from the ventilating end groove portion 168 of the front wall. In addition, stepped portions 182 protruding toward each other are formed at an intermediate height of the front wall, and the second heat guide surface portion 186 is formed with a narrower width than the first heat guide surface portion 184 by the stepped portions 182. It is formed as a concave surface with In this way, by forming the heat induction surface portion in the form of upper and lower light (上狹下廣), it is possible to rapidly diffuse the heat inside the protective cap 160 to the outside.

The invention disclosed above can be variously modified within a range that does not damage the basic idea. That is, all of the above embodiments should be interpreted as illustratively, and not limitedly interpreted. Therefore, the scope of protection of the present invention should be determined according to the appended claims, not the above-described embodiments, and if the components defined in the appended claims are substituted with equivalents, it should be considered as belonging to the protection scope of the present invention.

100: insulating substrate 102: first substrate via hole
104: first substrate casting unit 106: second substrate via hole
108: second substrate casting unit 110: first fusible body connection electrode
112: first electrode via hole 114: first electrode casting unit
120: second fusible body connection electrode 122: second electrode via hole
124: second electrode casting unit 130: soluble body
140: first lower connection electrode 142: first via
144: first vertical curvature terminal wall 150: second lower connection electrode
152: second via 154: second vertically curved terminal wall
160: protective cap 162, 164: ventilation long groove
166, 168: ventilation end groove 174, 184: first heat induction surface
176, 186: second heat induction surface portion 182: stepped portion

Claims (6)

In the SMD (Surface Mount Device) type protection device,
An insulating substrate having a plurality of substrate via holes penetrating vertically along the longitudinal directions of both sides of the long side portion, and having a plurality of substrate cascading portions concave inwardly formed between each of the via holes on both sidewalls;
A plurality of electrode cascades disposed to be spaced apart from each other on the upper surface of the insulating substrate, each electrode via hole formed in communication with the substrate via hole along a length direction, and concave inward at a position corresponding to the substrate cascade A first fusible element connecting electrode and a second fusible element connecting electrode which are additionally formed;
A soluble body that connects the first soluble body connection electrode and the second soluble body connection electrode and melts at a melting current or more;
They are disposed to be spaced apart from each other on the lower surface of the insulating substrate, respectively, through the substrate via hole along the length direction, and connected to the electrode via hole, and a via in which a conductor is charged is vertically installed, and the substrate cascade at the end thereof. A first lower connection electrode and a second lower connection electrode bent upward to correspond to a portion and on which a vertically curved terminal wall connected to the electrode cascade is installed; And
A protective cap coupled to the upper portion of the insulating substrate to protect the fusible material
High current protection device comprising a.
The method of claim 1,
The substrate via-hole is formed in 3 to 5 respectively along the length direction of both sides of the insulating substrate, the substrate casting part is a high current protection device that is formed in two to four, respectively, on both sidewalls of the insulating substrate.
The method according to claim 1 or 2,
The protective cap is configured to form a space in which the upper surface is sealed and the lower surface is recessed toward the upper side to accommodate the fusible material, and a high current protection device having a vented long groove cut toward the upper side of each of the sidewalls of the long side.
The method of claim 3,
The protection cap is a high current protection device further comprising a ventilating short groove cut toward the upper side in each of the front wall and the rear wall of the short side portion.
The method of claim 4,
The protection cap is a high current protection device further comprising a heat induction surface concave inwardly in the longitudinal direction on each of the front wall and the rear wall.
The method of claim 5,
The heat guide surface portion has a first heat guide surface portion extending from the ventilating end groove portion, and a stepped portion protruding toward each other from the front wall and the rear wall, thereby having a narrower width than the first heat guide surface portion. 2 A high-current protection device that is formed so that the heat induction surface is divided in the form of upper and lower light.

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