CN108701566A - Protection element - Google Patents

Abstract

Offer efficiently carrys out the heat of spontaneous heating body to fuse cell transmission and prevents thermal diffusion, to the excellent protection element of fast thawing.Fuse element 1 has:Insulating substrate 2;The 1st surface electrode 3 and the 2nd surface electrode 4 in the surface 2a of insulating substrate 2 is set in a manner of opposite one another;Heater 5;The heater extraction electrode 6 being electrically connected with heater 5;Fuse cell 7 is connected across the 1st surface electrode 3, the 2nd surface electrode 4 and heater extraction electrode 6, is melted by the heating of heater 5, to block the current path between the 1st surface electrode 3 and the 2nd surface electrode 4;The 1st backplate 3a and the 2nd backplate 4a in the back side 2b of insulating substrate 2 is set;And the 1st lateral conduction portion 3b and the 2nd lateral conduction portion 4b, it is formed in side 2c, 2d, 2e of insulating substrate 2, it is separately connected the 1st surface electrode 3 and the 2nd surface electrode 4 and the 1st backplate 3a and the 2nd backplate 4a, between the surface 2a and back side 2b of insulating substrate 2, the 1st surface electrode 3 of connection and the 2nd surface electrode 4 and whole current paths of the 1st backplate 3a and the 2nd backplate 4a are constituted.

Description

protection element

technical field

The present invention relates to a protection element that is installed on a current path and cuts off the current path by blowing a fuse element by heating of a heater when a current exceeding a rated current flows. This application claims priority based on Japanese Patent Application No. Japanese Patent Application No. 2016-058426 for which it applied in Japan on March 23, 2016, and this application is taken in in this application by reference.

Background technique

Conventionally, protection elements have been used to cut off the current path by blowing the fuse unit by heating of a heater when a current exceeding a rated current flows. As such a protective element, there is known a surface mount type protective element in which a functional chip having electrodes and a fuse unit mounted on an insulating substrate is formed and the chip is mounted on a circuit board.

In the protective element as described above, since the heater is energized based on a signal from an external circuit to heat and fuse the fuse unit, it is possible to use a switch that blocks a current path at a timing controlled by the external circuit. Such a protection element is employed as a protection circuit of a secondary battery such as a lithium ion battery, for example.

In recent years, for example, electric acceleration (assist) bicycles, electric tools, etc. require a large current output in the use of secondary batteries such as lithium-ion batteries, and the rated current of the protection circuit has increased. fuse unit.

In the technique described in Patent Document 1, a protection element using a fuse unit capable of handling a large current is disclosed.

prior art literature

patent documents

Patent Document 1: Japanese Unexamined Patent Publication No. 2015-035281.

Contents of the invention

The problem to be solved by the invention

However, in the technology described in the above-mentioned Patent Document 1, although the current path conducting from the front surface to the back surface of the insulating substrate is not clearly stated, in order to cope with large currents, the resistance value is increased at the portion corresponding to the conductive path on the side surface of the insulating substrate. It is necessary to form a via hole that directly connects the front surface and the back surface of the insulating substrate, or to fill a current path in the via hole with a conductor to reduce the resistance value.

In addition, in the technique described in Patent Document 1 above, when a via hole directly connecting the front and back surfaces of the insulating substrate is formed, or a current path in the via hole is filled with a conductor, heat from the heater passes through the current. The path spreads, making it difficult to concentrate heat and transfer it to the fuse unit, and the quick melting performance of the fuse unit deteriorates.

Therefore, an object of the present invention is to provide a protection element capable of handling a large current without hindering miniaturization, efficiently transferring heat from a heater to a fuse unit, and having excellent quick-melt properties.

Solution to the problem

In order to solve the above-mentioned problems, the protection element related to the present invention includes: an insulating substrate; a first surface electrode and a second surface electrode, which are arranged on the surface of the insulating substrate so as to face each other; a heating element; a heating element lead-out electrode, Electrically connected with the heating element; the fuse unit is connected across the first surface electrode, the second surface electrode and the heating element lead-out electrode, and is melted by the heating of the heating element, thus cutting off the first surface electrode and the second surface electrode. The current path of the current path; the first back electrode and the second back electrode are arranged on the back side of the insulating substrate; The front electrode, the first back electrode, and the second back electrode constitute a current path connecting all of the first and second front electrodes to the first and second back electrodes between the front and back of the insulating substrate.

In addition, in order to solve the above-mentioned problems, the protection element according to the present invention includes: an insulating substrate; a first surface electrode and a second surface electrode arranged on the surface of the insulating substrate so as to face each other; a heating element; The electrode is electrically connected to the heating body; the fuse unit is connected across the first surface electrode, the second surface electrode, and the heating element lead-out electrode, and is melted by heating of the heating element, thereby cutting off the first surface electrode and the second surface electrode The current path between them; the first back electrode and the second back electrode are arranged on the back side of the insulating substrate; and the first through-conducting portion and the second through-conducting portion are formed as holes penetrating through the insulating substrate, respectively connecting the first surface The electrode, the second surface electrode, and the first back electrode and the second back electrode form a conductive path between the front surface and the back surface of the insulating substrate. The first surface convex portion and the second surface convex portion protrude from the area where the second through-conduction portion contacts.

Invention effect

According to the present invention, by disposing the current path that conducts the front surface and the back surface of the insulating substrate only on the side surface of the insulating substrate, the heat from the heater can be concentratedly transferred to the fuse unit without spreading to the through hole, thereby enabling Improve the quick melting performance of the fuse unit. In addition, when the current path connecting the surface and the back surface of the insulating substrate is a through hole and the through hole is provided, only the surface protrusion protruding from the surface electrode to the periphery of the current path is formed to reduce the area of the surface electrode, thereby preventing The heat is diffused to the surface electrode, and the heat can be concentratedly transferred to the fuse unit, which can improve the fast melting performance of the fuse unit.

Description of drawings

[ Fig. 1] Fig. 1 is a plan view showing a fuse unit seen through in the fuse element according to the first embodiment.

[ Fig. 2] Fig. 2 is a cross-sectional view taken along line AA' shown in Fig. 1 .

[FIG. 3] FIG. 3 is a schematic diagram for explaining the shape of the first side conductive part, and is a plan view of the first surface electrode viewed from above. FIG. 3(A) shows a semicircular shape, and FIG. 3(B) shows a rectangular groove Shape, Figure 3(C) shows the shape of a half-slotted hole, and Figure 3(D) shows the shape of a wave groove.

[FIG. 4] FIG. 4 is an equivalent circuit diagram illustrating the circuit structure of the fuse element. FIG. 4(A) shows the state before the fuse element operates, and FIG. 4(B) shows the state of the fuse unit after the fuse element operates. molten state.

[ Fig. 5] Fig. 5 is a plan view showing a state in which the fuse element in Fig. 1 operates and the fuse unit is melted.

[ Fig. 6] Fig. 6 is a cross-sectional view taken along line AA' shown in Fig. 5 .

[ Fig. 7] Fig. 7 is a plan view showing a fuse unit seen through in the fuse element according to the first modified example.

[ Fig. 8] Fig. 8 is a plan view showing a fuse unit seen through in the fuse element according to a second modified example.

[ Fig. 9] Fig. 9 is a plan view showing a fuse unit seen through in the fuse element according to a third modification.

[ Fig. 10] Fig. 10 is a plan view showing a fuse unit seen through in the fuse element according to a fourth modification.

[ Fig. 11] Fig. 11 is a plan view showing a fuse unit seen through in the fuse element according to the second embodiment.

[ Fig. 12] Fig. 12 is a plan view of the fuse element in Fig. 11 viewed from the back.

[ Fig. 13] Fig. 13 is a sectional view taken along line AA' shown in Fig. 11 .

[ Fig. 14] Fig. 14 is a plan view showing a state in which the fuse element in Fig. 11 operates and the fuse unit is melted.

[ Fig. 15] Fig. 15 is a cross-sectional view taken along line AA' shown in Fig. 14 .

Detailed ways

Hereinafter, as a protection element to which the present invention is applied, a fuse element will be described in detail with reference to the drawings. In addition, this invention is not limited only to the following embodiment, It is obvious that a various change is possible in the range which does not deviate from the summary of this invention. In addition, the drawings are schematic, and ratios of dimensions and the like may be different from reality. Specific dimensions and the like should be judged in consideration of the following descriptions. In addition, it is obvious that the relationship or ratio of a mutual dimension differs among drawings also.

[the first embodiment]

As shown in FIG. 1 and FIG. 2 , the fuse element 1 according to the first embodiment is surface-mounted on a circuit board such as a protection circuit of a lithium-ion secondary battery by, for example, reflow soldering, so that the fuse unit 7 is assembled to the lithium-ion battery. On the charging and discharging path of the ion secondary battery.

In this protection circuit, when a large current exceeding the rating of the fuse element 1 flows, the fuse unit 7 is blown due to self-heating (Joule heat), thereby blocking the current path. In addition, in this protection circuit, electricity is supplied to the heating element 5 at predetermined timing by a current control element provided on a circuit board on which the fuse element 1 is mounted, and the heat generated by the heating element 5 blows the fuse unit 7 to cut off the current path. In addition, FIG. 1 is a plan view showing the fuse element 1 omitting the case, and FIG. 2 is a cross-sectional view of the fuse element 1 .

[fuse element]

As shown in FIG. 1 and FIG. 2, the fuse element 1 includes: an insulating substrate 2; a first surface electrode 3 and a second surface electrode 4 arranged on the surface 2a of the insulating substrate 2 in a manner facing each other; a heating element 5; The heating element lead-out electrode 6 electrically connected with the heating element 5; the fuse unit 7 is connected across the first surface electrode 3, the second surface electrode 4 and the heating element lead-out electrode 6; Heated and melted to cut off the current path between the first surface electrode 3 and the second surface electrode 4; the first back surface electrode 3a and the second back surface electrode 4a provided on the back surface 2b of the insulating substrate 2; and the first side surface conductive part 3b and the second side surface conductive portion 4b are formed on the side surface of the insulating substrate 2, respectively connected to the first surface electrode 3 and the second surface electrode 4 and the first back electrode 3a and the second back electrode 4a, on the surface 2a of the insulating substrate 2 Between the back surface 2b and the first surface electrode 3 and the second surface electrode 4, a current path connecting all of the first back electrode 3a and the second back electrode 4a is formed.

In addition, the fuse element 1 is provided with: an insulator 9 that covers the heating element 5 and prevents the contact between the heating element 5 and the heating element lead-out electrode 6; 10 and the second heating body electrode 11. One end of the heating element lead-out electrode 6 is connected to the second heating element electrode 11 , and the other end is connected to an intermediate portion of the fuse unit 7 .

In addition, the fuse element 1 is provided with: a third back electrode 10a provided on the back surface 2b of the insulating substrate 2; The back electrode 10 a serves as an entire conductive path between the front surface 2 a and the back surface 2 b of the insulating substrate 2 .

Here, the entire current path between the front surface 2a and the back surface 2b of the insulating substrate 2 means that the first surface electrode 3, the second surface electrode 4, and the first heat generating body electrode 10 are connected to the first back surface electrode 3a, the second A current path through which the back electrode 4 a and the third back electrode 10 a are respectively connected. Therefore, it shows that the current path is formed only on the side surface of the insulating substrate 2 . In other words, the fuse element 1 has a structure in which no current path is formed except on the side surface of the insulating substrate 2 .

Specifically, the first side conductive portion 3b, the second side conductive portion 4b, and the third side conductive portion 10b in the fuse element 1 are provided on the first side 2c, the second side 2d, and the third side of the insulating substrate 2, respectively. Side 2e.

Since the fuse element 1 does not form a current path other than the side surface of the insulating substrate 2, there is no current path such as a through hole in the central portion of the insulating substrate, so the heat generated from the heating element 5 does not pass through the central portion of the insulating substrate. The holes and the like are diffused so that the fuse unit 7 can be overheated intensively.

[insulating substrate]

The insulating substrate 2 is formed in a square shape using an insulating member such as alumina, glass ceramics, mullite, or zirconia, for example. In addition, materials used for printed wiring boards such as glass epoxy substrates and phenol substrates may be used for the insulating substrate 2 . In the insulating substrate 2 , the side surfaces facing each other are the first side surface 2c and the second side surface 2d, and the remaining side surfaces are the third side surface 2e and the fourth side surface 2f which are facing each other.

[1st surface electrode and 2nd surface electrode]

The first surface electrode 3 and the second surface electrode 4 are separately arranged on the surface 2a of the insulating substrate 2 in the vicinity of opposing side edges to be open circuits, and are mounted with a fuse unit 7 to be electrically connected via the fuse unit 7 . In addition, when a large current exceeding the rated current flows through the fuse element 1 and the fuse unit 7 is blown due to self-heating (Joule heat), or the heating element 5 generates heat along with energization and the fuse unit 7 is blown, the first surface The current path of the electrode 3 and the second surface electrode 4 is blocked.

As shown in FIG. 1 and FIG. 2, the first surface electrode 3 and the second surface electrode 4 are connected to the outside provided on the back surface 2b through half-through holes respectively provided on the first side surface 2c and the second side surface 2d of the insulating substrate 2. The electrodes, that is, the first back electrode 3 a and the second back electrode 4 a are connected. The fuse element 1 is connected to a circuit board on which an external circuit is formed via the first back electrode 3a and the second back electrode 4a, and constitutes a part of a current path of the external circuit. Therefore, the half-through holes provided on the first side surface 2c and the second side surface 2d constitute the first side surface conductive portion 3b and the second side surface conductive portion 4b.

The first surface electrode 3 and the second surface electrode 4 can be formed using general electrode materials such as Cu and Ag. In addition, it is preferable to plate a film such as Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating, etc. on the surfaces of the first surface electrode 3 and the second surface electrode 4 by a known method such as plating treatment. Thereby, the fuse element 1 can prevent the oxidation of the first surface electrode 3 and the second surface electrode 4, and can prevent the rating from fluctuating due to an increase in the on-resistance.

In addition, when the fuse element 1 is mounted by reflow soldering, it is possible to prevent the first surface electrode 3 and the second surface electrode 4 from being connected to the fuse unit 7 by the solder for connection or having a low melting point formed on the outer layer of the fuse unit 7. In the case of a metal layer, the low melting point metal is melted and eroded (solder erosion).

[heating stuff]

The heating element 5 is a conductive member that generates heat when energized, and is made of, for example, nickel chromium, W, Mo, Ru, Cu, Ag, or an alloy containing these as main components. The heating element 5 can be formed by mixing powders of these alloys, compositions, and compounds with resin binders, etc. to make a paste, patterning it on the insulating substrate 2 by screen printing technology, and performing sintering. . In addition, one end of the heating element 5 is connected to the first heating element electrode 10 , and the other end thereof is connected to the second heating element electrode 11 .

In the fuse element 1 , an insulator 9 is disposed so as to cover the heating element 5 formed on the surface 2 a of the insulating substrate 2 , and a heating element lead-out electrode is formed so as to face the heating element 5 via the insulator 9 . 6. In order to efficiently transfer the heat of the heating element 5 to the fuse unit 7 , an insulator may also be laminated between the heating element 5 and the insulating substrate 2 . As the insulator 9, for example, a glass material can be used.

One end of the heating element lead-out electrode 6 is connected to the second heating element electrode 11 , and is continuous with one end of the heating element 5 via the second heating element electrode 11 . In addition, the second heating element electrode 11 is formed on the surface 2 a side of the insulating substrate 2 , and the first heating element electrode 10 is formed from the surface 2 a side of the insulating substrate 2 to the third side surface 2 e side. In addition, the first heat generating body electrode 10 is connected to the third back surface electrode 10a formed on the back surface 2b of the insulating substrate 2 through the half-through hole formed on the third side surface 2e. Therefore, the half-through hole formed in the third side surface 2e constitutes the third side surface conductive portion 10b.

In the heating element 5, the fuse element 1 is mounted on the circuit board, and is connected to an external circuit formed on the circuit board through the third back electrode 10a. Furthermore, the heating element 5 is energized and generates heat through the third back electrode 10a at a predetermined timing to cut off the current path of the external circuit, and fuse unit 7 connecting the first front electrode 3 and the second front electrode 4 can be fused. In addition, the fuse unit 7 is blown, and the current path of the heat generating body 5 itself is also cut off, so that heat generation stops.

[Heating body lead-out electrode]

The heating element lead-out electrode 6 can be formed using a general electrode material such as Cu or Ag. In addition, it is preferable to plate Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating or the like on the surface of heating element lead-out electrode 6 by a known method such as plating treatment.

[The first heating element electrode and the second heating element electrode]

The first heating body electrode 10 and the second heating body electrode 11 are respectively arranged separately and open in the vicinity of opposing side edges on the surface 2 a of the insulating substrate 2 , and are electrically connected via the heating body 5 by mounting the heating body 5 .

The first heating body electrode 10 and the second heating body electrode 11 can be formed using common electrode materials such as Cu or Ag. In addition, it is preferable to use known methods such as plating treatment to plate Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating, etc. on the surfaces of the first heating element electrode 10 and the second heating element electrode 11. membrane.

In addition, here, the first back electrode 3a and the first side surface conductive portion 3b can be formed of the same material as the first surface electrode 3, and the second back electrode 4a and the second side surface conductive portion 4b can be made of the same material as the second surface electrode 4. They are formed of the same material, and the third back electrode 10 a and the third side conductive portion 10 b can be formed of the same material as that of the first heat generating body electrode 10 .

[Fuse unit]

The fuse unit 7 is made of a material that melts quickly due to the heat generated by the heating element 5 , and for example, a low-melting-point metal such as solder or lead-free solder mainly composed of Sn can be preferably used.

In addition, the fuse unit 7 can use high-melting-point metals such as In, Pb, Ag, Cu, or an alloy mainly composed of any of these, or the inner layer can be a low-melting-point metal layer and the outer layer can be a low-melting-point metal layer. A laminate of a low-melting-point metal and a high-melting-point metal such as a high-melting-point metal layer. By containing the high-melting-point metal and the low-melting-point metal, when the fuse element 1 is mounted by reflow soldering, even if the reflow temperature exceeds the melting temperature of the low-melting-point metal and the low-melting-point metal melts, the outflow of the low-melting-point metal to the outside is suppressed, and the fuse element 1 can be maintained. The shape of the fuse unit 7. In addition, at the time of fusing, the high-melting-point metal is eroded (solder erosion) by melting the low-melting-point metal, so that rapid fusing can be performed at a temperature lower than the melting point of the high-melting-point metal.

In addition, the fuse unit 7 is connected to the heating element lead-out electrode 6 and the first surface electrode 3 and the second surface electrode 4 by solder or the like. The fuse unit 7 can be easily connected by reflow soldering. The fuse unit 7 is mounted on the heat generating body lead electrode 6 , overlaps with the heat generating body lead electrode 6 , and also overlaps with the heat generating body 5 . In addition, the fuse unit 7 connected between the first surface electrode 3 and the second surface electrode 4 is fused between the first surface electrode 3 and the second surface electrode 4, thereby disconnecting the first surface electrode 3 and the second surface electrode. 2 between surface electrodes 4. That is, the central portion of the fuse unit 7 is supported by the heat generating body lead-out electrode 6 , and the central portion supported by the heat generating body lead-out electrode 6 is set as a fuse portion.

In addition, the fuse unit 7 is coated with flux (not shown) for oxidation prevention, wettability improvement, and the like. By holding the flux in the fuse unit 7 , oxidation of the fuse unit 7 and an increase in the fusing temperature associated with oxidation are prevented, and fluctuations in fusing characteristics are suppressed, enabling rapid fusing.

[side conduction part]

Here, the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the second side surface conductive portion 10b will be described in detail.

The first side conductive portion 3b, the second side conductive portion 4b, and the second side conductive portion 10b can be formed using common electrode materials such as Cu or Ag. In addition, it is preferable to use a known method such as plating treatment to plate Ni/Au plating, Ni/Pd plating, Ni/Pd plating, Ni/ Coatings such as Pd/Au plating.

Next, the shapes of the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the second side surface conductive portion 10b will be described based on FIG. 3 . In addition, only the first side surface conductive part 3b will be described below, but the shapes of the second side surface conductive part 4b and the second side surface conductive part 10b may also be the same shape, so the description will be omitted.

The first side surface conductive portion 3 b shown in FIG. 3(A) is formed by adding a semicircular notch to the insulating substrate 2 to form a recess, and patterning a conductive material on the recess. The first side conductive portion 3 b is a so-called half-through hole, and electrically connects the first front surface electrode 3 and the first back surface electrode 3 a between the front surface 2 a and the back surface 2 b of the insulating substrate 2 .

Regarding the first side conductive portion 3b shown in FIG. 3(A), circular through-holes can be provided between adjacent individual insulating substrates when the insulating substrate 2 is cut out from the mother substrate not shown, and the through-hole Each insulating substrate is cut out as a boundary with a hole, and formed as a semicircular recess. The through-holes can be easily produced by providing cylindrical protrusions in the mold used to form the motherboard, and thus are easy to manufacture.

In addition, the first side conductive portion 3b may also be formed in other shapes. For example, the first side conductive portion 3c shown in FIG. Formed by patterning conductive material. The first side surface conductive portion 3 c electrically connects the first surface electrode 3 and the first back surface electrode 3 a between the front surface 2 a and the back surface 2 b of the insulating substrate 2 .

The first side conductive portion 3c shown in FIG. 3(B) can be formed by providing a rectangular through hole between adjacent individual insulating substrates when the insulating substrate 2 is cut out from the mother substrate not shown, and the through hole is used as a boundary. Each insulating substrate was cut out to form a concave portion in the shape of a rectangular groove. The through hole can be easily produced by providing a rectangular prism-shaped protrusion in a mold when forming a mother board, and thus is easy to manufacture.

Compared with the first side conductive part 3b shown in FIG. 3(A), the first side conductive part 3c shown in FIG. As a result, the width of the current path can be enlarged to reduce the resistance value, which is suitable for handling large currents.

In addition, the first side conductive portion 3b can also be formed in other shapes. For example, the first side conductive portion 3d shown in FIG. The recesses are formed by patterning the conductive material. The first side surface conductive portion 3 d electrically connects the first front surface electrode 3 and the first back surface electrode 3 a between the front surface 2 a and the back surface 2 b of the insulating substrate 2 .

With respect to the first side conductive portion 3d shown in FIG. Each insulating substrate is cut out as a boundary with a through hole, and formed as a semi-long hole-shaped concave portion. The through hole can be easily produced by providing a columnar protrusion corresponding to the shape of the rectangular long hole in a mold when forming the mother board, and thus is easy to manufacture.

Compared with the first side conductive portion 3b shown in FIG. 3(A), the first side conductive portion 3d shown in FIG. As a result, the width of the current path can be enlarged to reduce the resistance value, which is suitable for handling large currents.

In addition, the first side conductive portion 3b can also be formed in other shapes. For example, the first side conductive portion 3e shown in FIG. The recesses are formed by patterning the conductive material. The first side surface conductive portion 3 e electrically connects the first surface electrode 3 and the first back surface electrode 3 a between the front surface 2 a and the back surface 2 b of the insulating substrate 2 .

Regarding the first side conductive part 3e shown in FIG. Each insulating substrate is cut out as a boundary by the through hole, and formed as a groove-shaped concave portion. The through hole can be easily produced by providing a columnar protrusion corresponding to the shape of the wavy long hole in the mold when forming the motherboard, and thus is easy to manufacture.

Compared with the first side conductive part 3b shown in FIG. 3(A), the first side conductive part 3e shown in FIG. As a result, the width of the current path can be enlarged to reduce the resistance value, which is suitable for handling large currents.

Summarizing the shapes of the above-mentioned recesses, it is possible to obtain a larger area of the recesses by constituting the side surface of the insulating substrate 2 with a non-planar surface including a curved surface. As a result, the width of the current path can be enlarged and the resistance value can be reduced. current is suitable.

In addition, the fuse element 1 is a component that realizes a small and high-rated protection element. For example, while the size of the insulating substrate 2 is as small as 2 to 3 mm×1 to 2 mm, the resistance value is 0.5 to 1 mΩ and 50 to 60 A. Rated high rating. Furthermore, the invention is obviously applicable to protective elements of all sizes, resistance values and current ratings. In this embodiment, the size of the insulating substrate 2 is set to 2.7mm×1.8mm.

Further, regarding the fuse element 1 , an unillustrated cover member that protects the inside and prevents scattering of the melted fuse unit 7 is mounted on the surface 2 a of the insulating substrate 2 . The cover member has side walls mounted on the surface 2 a of the insulating substrate 2 , and a top surface constituting the upper surface of the fuse element 1 . The cover member can be formed using an insulating member such as thermoplastics, ceramics, or a glass epoxy substrate, for example. In addition, the characteristic configuration of the present invention is the internal configuration of the cover member, and therefore, reference to the cover member will be omitted in the following description.

[Circuit configuration]

Here, the circuit configuration of the fuse element 1 and the interruption operation of the conduction path will be described. As shown in Figure 1 and Figure 4(A), the fuse element 1 is connected across the fuse unit 7 from the first surface electrode 3 to the second surface electrode 4, and the heating element lead-out electrode is connected to the middle part of the fuse unit 7 6. In addition, the heating element lead-out electrode 6 is connected to the second heating element electrode 11 , the heating element 5 , and the first heating element electrode 10 in the order opposite to the side connected to the fuse unit 7 . Therefore, the fuse element 1 can be said to be connected from the first surface electrode 3, the second surface electrode 4, and the first heating element electrode 10 through the first side surface conductive portion 3b, the second side surface conductive portion 4b, and the second side surface conductive portion. The first back electrode 3a, the second back electrode 4a, and the third back electrode 10a connected to each other at 10b serve as a three-terminal element as an external terminal.

The fuse element 1 is configured such that the current of the main circuit flows from the first surface electrode 3 to the second surface electrode 4, and when the current flows through the first heating element electrode 10, the heating element 5 generates heat, as shown in Fig. 5 and Fig. 5 . 6 and FIG. 4(B), the fuse unit 7 is melted, and the molten body 7a aggregates on the heating element lead-out electrode 6, thereby cutting the fuse unit 7. Accordingly, in the fuse element 1 , the current path between the first surface electrode 3 and the second surface electrode 4 is blocked, and the current path to the heating element 5 is also blocked.

[Modification 1]

Next, modified examples of the fuse element 1 described above will be described. In addition, the same code|symbol is attached|subjected to the part substantially equivalent to the fuse element 1 demonstrated above, and description is abbreviate|omitted, and the difference is demonstrated. In addition, as an equivalent circuit, since it is the same as the structure demonstrated with FIG. 4, description is abbreviate|omitted.

In the structure of the fuse element 20 according to Modification 1, as shown in FIG. 7, the first surface electrode 3 is extended to the fourth side surface 2f of the insulating substrate 2, and the first side surface conductive portion 3b is not provided, and the first side surface The conductive part 3b1 is arranged on the fourth side 2f of the insulating substrate ₂ , the second surface electrode 4 is extended to the third side 2e of the insulating substrate ₂ , and the second side conductive part 4b is not provided, and the second side conductive part 4b1 It is provided on the third side surface 2 e of the insulating substrate 2 , and the first side conductive portion 3 b ₁ and the second side conductive portion 4 b ₁ are arranged at diagonal positions of the insulating substrate 2 .

In addition, the illustration is omitted, but the fuse element 20 is on the back surface 2b side of the insulating substrate 2, the first back electrode 3a is extended to the fourth side surface 2f of the insulating substrate ₂ , and is connected to the first side conductive part 3b1, and the second The back electrode 4a is extended to the third side surface 2e of the insulating substrate ₂ , and is connected to the second side surface conductive portion 4b1.

In the fuse element 20, the _first side surface conductive portion 3b1 and the second side surface conductive portion 4b1 are arranged at _a position far from the heating element 5, so the effect of preventing heat diffusion from the heating element 5 is improved, and the heat is easily heated. Focus on fuse unit 7.

[Modification 2]

In addition, a modified example of the fuse element 1 described above will be described. In addition, the same code|symbol is attached|subjected to the part substantially equivalent to the fuse element 1 demonstrated above, and description is abbreviate|omitted, and the difference is demonstrated. In addition, as an equivalent circuit, since it is the same as the structure demonstrated with FIG. 4, description is abbreviate|omitted.

The fuse element 30 according to Modification 2, as shown in FIG. The first side conductive part 3b1 is provided on the fourth side 2f of the insulating substrate ₂ , the second surface electrode 4 is extended to the third side 2e of the insulating substrate 2, and the second side conductive part 4b is provided but the second side is provided on the third side 2e of the insulating substrate 2. The side conductive portion 4b ₁ arranges the first side conductive portion 3b and the second side conductive portion 4b at opposing positions, and arranges the first side conductive portion 3b ₁ and the second side conductive portion 4b ₁ on opposite sides of the insulating substrate 2. corner position.

In addition, the illustration is omitted, but the fuse element 30 is on the back surface 2b side of the insulating substrate 2, and the first back electrode 3a is extended to the fourth side surface 2f of the insulating substrate ₂ and connected to the first side conductive part 3b1, and the second The back electrode 4a is extended to the third side surface 2e of the insulating substrate ₂ , and is connected to the second side surface conductive portion 4b1.

In the fuse element 30, in addition to the first side conductive portion 3b and the second side conductive portion 4b, it also has the first side conductive portion 3b ₁ and the second side conductive portion 4b ₁ , so there are many current paths. The overall path can reduce the resistance value. Therefore, the fuse element 30 can cope with a large current by reducing the resistance value of the current path.

[Modification 3]

In addition, a modified example of the fuse element 1 described above will be described. In addition, the same code|symbol is attached|subjected to the part substantially equivalent to the fuse element 1 demonstrated above, and description is abbreviate|omitted, and the difference is demonstrated. In addition, as an equivalent circuit, since it is the same as the structure demonstrated with FIG. 4, description is abbreviate|omitted.

_The fuse element 40 according to Modification ₃ , as shown in FIG. The conduction path is provided with two current paths of the second side conductive portion 4b ₂ and the second side conductive portion 4b ₃ on the second side 2d of the insulating substrate 2, respectively connecting the first side conductive portion 3b ₂ and the second side conductive portion 4b. ₂ are arranged at opposing positions, and the first side surface conductive portion _3b3 and the second side surface conductive portion _4b3 are arranged at opposing positions.

In addition, illustration is omitted, but with regard to the fuse element 40, on the back surface 2b side of the insulating substrate ₂ , the first back electrode _3a is connected to the first side conductive part 3b2 and the first side conductive part 3b3, and the second back electrode 4a is connected to the second side conductive portion 4b ₂ and the second side conductive portion 4b ₃ .

In the fuse element 40, the first side conductive part 3b and the _second side conductive part 4b are respectively made into the first side conductive part 3b2, the first side conductive part _3b3 and the _second side conductive part 4b2, and the second side conductive part Due to the multiple structure of the portion _4b3 , the current path becomes multiple, and the resistance value can be reduced as a whole of the current path. Therefore, the fuse element 40 can cope with a large current by reducing the resistance value of the current path.

In addition, in the fuse element 40, the first side conductive portion 3b ₂ , the first side conductive portion 3b ₃ , the second side conductive portion 4b ₂ , and the second side conductive portion 4b ₃ are provided on the first side surface of the insulating substrate 2, respectively. 2c and the second side surface 2d, that is, are respectively provided on the same side surface. Since the part where the insulating substrate is cut out from the mother substrate is the place where the through hole is lightened, the cutting work can be easily performed at the part where the plurality of through holes are arranged in parallel.

[Modification 4]

In addition, a modified example of the fuse element 1 described above will be described. In addition, the same code|symbol is attached|subjected to the part substantially equivalent to the fuse element 1 demonstrated above, and description is abbreviate|omitted, and the difference is demonstrated. In addition, as an equivalent circuit, since it is the same as the structure demonstrated with FIG. 4, description is abbreviate|omitted.

A fuse element 50 according to Modification 4, as shown in FIG. The third side 2e of the insulating substrate 2 is provided with a first side conductive portion 3b ₄ , the second surface electrode 4 is extended to the third side 2e of the insulating substrate 2, and the second side conductive portion 4b is not provided, and on the second side of the insulating substrate 2 The second side conductive portion 4b ₄ is provided on the third side 2e, and the first side conductive portion 3b ₁ and the second side conductive portion 4b ₁ including the third side conductive portion 10b are disposed on the third side 2e of the insulating substrate 2, that is, on the same side. side.

In addition, the illustration is omitted, but the fuse element 50 is on the back surface 2b side of the insulating substrate 2, the first back electrode 3a is extended to the third side surface 2e of the insulating substrate 2, and is connected to the first side conductive part _3b4 , and the second The back electrode 4a is extended to the third side surface 2e of the insulating substrate 2, and is connected to the second side surface conductive portion _4b4 .

In the fuse element 50, including the third side conductive portion 10b, the _first side conductive portion 3b1 and the second side conductive portion _4b1 are disposed on the same side surface of the insulating substrate 2. Therefore, since the insulating substrate is cut out from the mother substrate When the separation part is used as a place to punch a through hole, the cutting operation can be easily performed.

Furthermore, in the fuse element 50, including the third side conductive portion 10b, the first side conductive portion 3b ₁ and the second side conductive portion 4b ₁ are disposed on the same side surface of the insulating substrate 2, so when mounted on the circuit board, Solder for connection is attracted to the third side conductive part 10b, the first side conductive part _3b4 , and the second side conductive part _4b4 , and the work of visually confirming whether the electrical connection is normal is completed by observing only one side surface, so that the work can be simplified. Connect to confirm itinerary.

[the second embodiment]

Next, a fuse element 60 according to the second embodiment will be described using FIGS. 11 to 15 . In addition, the same code|symbol is attached|subjected to the part substantially equivalent to the fuse element 1 demonstrated above, and description is abbreviate|omitted, and the difference is demonstrated. In addition, as an equivalent circuit, since it is the same as the structure demonstrated with FIG. 4, description is abbreviate|omitted.

In this protection circuit, when a large current exceeding the rating of the fuse element 60 flows, the fuse unit 7 is blown due to self-heating (Joule heat), thereby blocking the current path. In addition, in this protection circuit, electricity is supplied to the heating element 5 at predetermined timing by a current control element provided on a circuit board on which the fuse element 1 is mounted, and the heat generated by the heating element 5 blows the fuse unit 7 to cut off the current path. 11 is a plan view showing the fuse element 60 with the case omitted, FIG. 12 is a plan view of the fuse element 60 viewed from the rear side, and FIG. 13 is a cross-sectional view of the fuse element 60 .

[fuse element]

As shown in FIGS. 11 to 13, the fuse element 60 includes: an insulating substrate 2; a first surface electrode 3 and a second surface electrode 4 arranged on the surface 2a of the insulating substrate 2 in a manner to face each other; a heating element 5; The heating element lead-out electrode 6 electrically connected to the heating element 5; the fuse unit 7 is connected across the first surface electrode 3, the second surface electrode 4 and the heating element lead-out electrode 6, and is melted by heating of the heating element 5, Thus, the current path between the first surface electrode 3 and the second surface electrode 4; the first back surface electrode 3a and the second back surface electrode 4a provided on the back surface 2b of the insulating substrate 2; The penetrating conductive part 16 is formed as a hole penetrating the insulating substrate 2, and connects the first surface electrode 3 and the second surface electrode 4 with the first back electrode 3a and the second back electrode 4a respectively, and becomes the front surface 2a and the back surface of the insulating substrate 2. In the current path between 2b, the first surface electrode 3 and the second surface electrode 4 respectively have a first surface convex portion 3f and a first surface convex portion 3f protruding to the area in contact with the first penetrating conductive portion 15 and the second penetrating conductive portion 16. 2 surface convex portion 4f.

In addition, the fuse element 60 includes: an insulator 9 that covers the heating element 5 and prevents the contact between the heating element 5 and the heating element lead-out electrode 6; The second heating element electrode 11 . One end of the heating element lead-out electrode 6 is connected to the second heating element electrode 11 , and the other end is connected to an intermediate portion of the fuse unit 7 .

In addition, in the fuse element 60, as shown in FIG. 12 , the first back surface electrode 3a and the second back surface electrode 4a each have a first back surface protruding to a region in contact with the first penetrating conductive portion 15 and the second penetrating conductive portion 16. 1 rear convex part 3g and the 2nd rear convex part 4g.

In addition, the fuse element 60 has a first side conductive portion 3b and a second side conductive portion 4b formed on the side surface of the insulating substrate 2, and the first side conductive portion 3b and the second side conductive portion 4b are respectively connected to the first surface electrode 3. And the second surface electrode 4, the first back electrode 3a and the second back electrode 4a, and form a current path between the front surface 2a and the back surface 2b of the insulating substrate 2.

Specifically, the first side conductive portion 3b, the second side conductive portion 4b, and the third side conductive portion 10b in the fuse element 60 are provided on the first side 2c, the second side 2d, and the third side of the insulating substrate 2, respectively. Side 2e.

Here, the first surface convex portion 3f and the second surface convex portion 4f represent the rectangular shape described in the fuse element 1 described in the first embodiment, with respect to the first surface electrode 3 and the second surface electrode 4 . Part of the structure is formed at a portion close to the heating element 5 other than the region corresponding to the first through-conduction portion 15 and the second through-conduction portion 16 . In addition, in other words, it can also be said to be a region protruding from the main part of the first surface electrode 3 in order to connect the first surface electrode 3 and the first penetrating conductive portion 15 .

The fuse element 60 has a current path penetrating the insulating substrate 2 in addition to the first side surface 2c and the second side surface 2d of the insulating substrate 2, and the overall resistance value of the current path is reduced, so that it is easy to handle large currents.

In addition, the fuse element 60 is configured such that only in the area corresponding to the first penetrating conductive portion 15 and the second penetrating conductive portion 16 on the side close to the heating element 5 among the first surface electrode 3 and the second surface electrode 4 Forming the first surface convex portion 3f and the second surface convex portion 4f prevents the heat generated from the heating element 5 from diffusing to the first surface electrode 3 and the second surface electrode 4 , thereby concentrating and overheating the fuse unit 7 .

In addition, the fuse element 60 is configured such that, among the first back electrode 3a and the second back electrode 4a, the side close to the heating element 5 is the same as the first front electrode 3 and the second front electrode 4, only the first The regions corresponding to the penetrating conductive portion 15 and the second penetrating conductive portion 16 form the first rear surface convex portion 3g and the second surface convex portion 4g, so that the heat generated from the heating element 5 will not spread to the first rear surface electrode 3a and the second surface electrode 3a. The back electrode 4a can cause the fuse unit 7 to be overheated intensively.

In the fuse element 60 according to the second embodiment, since the heating element 5 is disposed on the surface 2a of the insulating substrate 2, the effect of preventing heat diffusion by the first surface protrusions 3f and the second surface protrusions 4f is particularly large.

Therefore, in the fuse element in which the heating element 5 is provided on the surface 2a of the insulating substrate 2, at least the first surface electrode 3 and the second surface electrode 4 only need to have the first surface convex portion 3f and the second surface convex portion 4f. The first rear convex portion 3g and the second rear convex portion 4g may not be provided.

In addition, in the fuse element in which the heating element 5 is provided on the back surface 2b of the insulating substrate 2, the effect of preventing heat diffusion by the first rear surface convex portion 3g and the second rear surface convex portion 4g is particularly large.

Therefore, in the fuse element in which the heating element 5 is provided on the back surface 2b of the insulating substrate 2, at least the first back surface electrode 3a and the second back surface electrode 4a may have the first back surface convex portion 3g and the second back surface convex portion 4g. The first surface convex portion 3f and the second surface convex portion 4f may not be provided.

Here, the first through-conduction portion 15 and the second through-conduction portion 16 are via holes, especially filled via holes filled with a conductive material, so that the effect of reducing the resistance value of the entire current path can be enhanced.

Here, in the case where the effect of reducing the resistance value by the first penetrating conductive portion 15 and the second penetrating conductive portion 16 is high, the first side conductive portion 3b and the second side conductive portion 4b may not be provided. However, in order to secure the mounting state on the circuit board or the like, it is preferable to leave the fuse element as a half-through hole for sucking the solder for bonding.

In addition, in the fuse element 60 , two first penetrating conductive portions 15 and two second penetrating conductive portions 16 are respectively provided. Therefore, in the fuse element 60, the first surface convex portion 3f and the second surface convex portion 4f corresponding to the first penetrating conductive portion 15 and the second penetrating conductive portion 16, and the first rear convex portion 3g and the second rear convex portion Two parts 4g are also provided.

In addition, the number of the first through-conduction portion 15 and the second through-conduction portion 16 and the shape and diameter of the through-hole can be appropriately changed after adjusting the resistance value of the current path, and are not limited to the description of this embodiment.

[Summarize]

As described above, the fuse element described as the first embodiment, each modified example, and the second embodiment can prevent thermal diffusion from the heating element to the outside of the fuse unit, and reduce the resistance value as a conductive path as a whole. Compatible with large currents while achieving miniaturization of components.

In addition, as the structure of the fuse element in the first embodiment, it is also possible to appropriately combine the structures of the above-mentioned modification examples. For example, it is obvious that any combination can be adopted for the shape, number, arrangement position, etc. of the side conductive portions.

Label description

1, 20, 30, 40, 50, 60 fuse element; 2 insulating substrate; 2a surface; 2b back; 2c 1st side; 2d 2nd side; 2e 3rd side; 2f 4th side; 3 1st surface electrode ; 3a the first back electrode; 3b, 3c, 3d, 3e the first side conductive part; 3f the first surface protrusion; 3g the first back protrusion; 4 the second surface electrode; 4a the second back electrode; 4d, 4e second side conductive part; 4f second surface convex part; 4g second back convex part; 5 heating element; 6 heating element lead-out electrode; 7 fuse unit; 7a melting body; 9 insulator; Electrode; 10a third back electrode; 10b third side conductive part; 11 second heating element electrode; 15 first through conductive part; 16 second through conductive part.

Claims (13)

1. a kind of protection element, has:

Insulating substrate;

1st surface electrode and the 2nd surface electrode are arranged in a manner of opposite one another on the surface of above-mentioned insulating substrate;

Heater;

Heater extraction electrode is electrically connected with above-mentioned heater;

Fuse cell is connected across above-mentioned 1st surface electrode, above-mentioned 2nd surface electrode and above-mentioned heater extraction electrode, is led to It crosses the heating of above-mentioned heater and melts, to block the electric current road between above-mentioned 1st surface electrode and above-mentioned 2nd surface electrode Diameter;

1st backplate and the 2nd backplate are arranged at the back side of above-mentioned insulating substrate;And

1st lateral conduction portion and the 2nd lateral conduction portion are formed in the side of above-mentioned insulating substrate, are separately connected above-mentioned 1st surface Electrode and above-mentioned 2nd surface electrode and above-mentioned 1st backplate and above-mentioned 2nd backplate, on the surface of above-mentioned insulating substrate Between the back side, constitutes and connect above-mentioned 1st surface electrode and above-mentioned 2nd surface electrode and above-mentioned 1st backplate and the above-mentioned 2nd Whole current paths of backplate.

2. protection element as described in claim 1, wherein above-mentioned insulating substrate with above-mentioned 1st surface electrode and the above-mentioned 2nd Recess portion is arranged in the corresponding side of surface electrode, and above-mentioned 1st lateral conduction portion and above-mentioned 2nd lateral conduction are formed in the recess portion Portion.

3. protection element as claimed in claim 2, wherein above-mentioned 1st lateral conduction portion and above-mentioned 2nd lateral conduction portion difference It is arranged in the side opposite one another of above-mentioned insulating substrate.

4. protection element as claimed in claim 3, wherein above-mentioned 1st lateral conduction portion and above-mentioned 2nd lateral conduction portion difference It is arranged in position opposite one another.

5. protection element as claimed in claim 3, wherein above-mentioned 1st lateral conduction portion and above-mentioned 2nd lateral conduction portion difference It is arranged from the position of position offset opposite one another.

6. protection element as claimed in claim 2, wherein above-mentioned 1st lateral conduction portion and the setting of above-mentioned 2nd lateral conduction portion In the same side of above-mentioned insulating substrate.

7. as claim 2 to claim 6 any one of them protection element, wherein above-mentioned 1st lateral conduction portion or on State the 2nd surface electrode be respectively set it is multiple.

8. such as any one of them protection element of claim 2 to claim 7, wherein above-mentioned recess portion is half-via.

9. such as any one of them protection element of claim 2 to claim 8, wherein above-mentioned recess portion is by including curved surface On-plane surface constitutes the side of above-mentioned insulating substrate.

10. a kind of protection element, has:

Insulating substrate;

1st surface electrode and the 2nd surface electrode are arranged in a manner of opposite one another on the surface of above-mentioned insulating substrate;

Heater;

Heater extraction electrode is electrically connected with above-mentioned heater;

Fuse cell is connected across above-mentioned 1st surface electrode, above-mentioned 2nd surface electrode and above-mentioned heater extraction electrode, is led to It crosses the heating of above-mentioned heater and melts, to block the current path between above-mentioned 1st surface electrode and the 2nd surface electrode;

1st backplate and the 2nd backplate are arranged at the back side of above-mentioned insulating substrate;And

1st perforation conductive part and the 2nd perforation conductive part, form as the hole for penetrating through above-mentioned insulating substrate, are separately connected above-mentioned 1st surface electrode and above-mentioned 2nd surface electrode and above-mentioned 1st backplate and above-mentioned 2nd backplate, become above-mentioned insulation Current path between the surface and the back side of substrate,

Above-mentioned 1st surface electrode and above-mentioned 2nd surface electrode are respectively provided with to above-mentioned 1st perforation conductive part and the 2nd perforation and lead Region the 1st surface protrusion outstanding and the 2nd surface protrusion that electric portion connects.

11. protection element as claimed in claim 10, wherein above-mentioned 1st backplate and above-mentioned 2nd backplate have respectively Oriented region the 1st back side protrusion outstanding to connect with above-mentioned 1st perforation conductive part and the 2nd perforation conductive part and the 2nd back side are convex Portion.

12. the protection element as described in claim 10 or claim 11, wherein above-mentioned 1st perforation conductive part and the 2nd perforation Conductive part is through-hole.

13. the protection element as described in claim 10 or claim 11, wherein above-mentioned 1st perforation conductive part and the 2nd perforation Conductive part is the filling type through-hole filled with conductive material inside hole.