CN110741457A

CN110741457A - Protective element

Info

Publication number: CN110741457A
Application number: CN201880039037.1A
Authority: CN
Inventors: 中岛慎太郎
Original assignee: Schott (japan) Corp
Current assignee: Schott (japan) Corp
Priority date: 2017-08-01
Filing date: 2018-07-31
Publication date: 2020-01-31
Anticipated expiration: 2038-07-31
Also published as: JP2019029244A; JP6912314B2; WO2019026904A1; KR102373602B1; CN110741457B; KR20190141719A; TW201921398A; TWI676202B

Abstract

The protection element (10, 20) is provided with an insulating substrate (11, 21), a plurality of electrodes (12, 22) provided on the insulating substrate (11, 21), an electrode filler (13, 23) of a low-melting metal filled between at least pairs of electrodes among the electrodes (12, 22), and a fuse element (14, 24) spanning between at least pairs of electrodes and covering the upper portion of the electrode filler (13, 23), the electrode filler (13, 23) being made of a metal material having a melting temperature equal to or lower than the liquidus temperature of the fuse element (14, 24).

Description

Protective element

Technical Field

The present invention relates to kinds of protection elements used for electric and electronic devices and the like.

Background

In recent years, with rapid spread of small electronic devices such as mobile devices, small and thin elements have been used as protection elements to be mounted in protection circuits of power supplies to be mounted thereon. As a protection circuit of the secondary battery pack, for example, a protection element of a Surface Mount Device (SMD) described in patent document 1 (japanese patent laid-open No. 2015-079608) is preferably used.

As these protection elements, there are non-recovery type protection elements that detect abnormal states such as excessive heat generation and overvoltage due to overcurrent of a device to be protected, or abnormal overheat due to sensing of ambient temperature, and operate a fuse under a predetermined condition to break a circuit. In the protection element, in order to realize safety of the device, when the protection circuit detects an abnormality occurring in the device, the resistance element is heated by a signal current from the protection circuit. In the protection element, a fuse element made of a fusible alloy material is fused by the heat generation to break an electric circuit, or the fuse element is fused by an overcurrent to break the electric circuit.

For example, patent document 1 and the like describe a protection element using a fuse element material composed of a low melting point metal material that melts at a soldering temperature and a soluble metal structure material laminated on the low melting point metal material, in the fuse element material of the protection element, the low melting point metal material that has been liquefied by a soldering operation is attached to a solid phase metal structure material at the temperature by interfacial tension, and the low melting point metal is supported and held so as not to be fused within hours.

When the soldering is completed and the circuit protection element is mounted on the circuit to be protected, the metallic structural material of the fuse element material is diffused or dissolved in the low melting point metallic material as a medium by the heat of the soldering, thereby being thinned. The metal structural material having a thinned layer is easily lost by abnormal overheating in the installation environment or heating by a heater of a built-in resistance heating element, and does not interfere with the subsequent fusing to operate.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2015-079608

Disclosure of Invention

Technical problem to be solved by the invention

From the viewpoint of coping with high current and reducing standby energy loss of the secondary battery, it is preferable to use a material having a low resistance value as much as possible for the fuse element used for the protection element. However, the fuse element applicable to the protection element has a limited variety of fusible alloys, and a fusible alloy having a low resistance value is not necessarily selected. In order to ensure practical use of the operating performance and the like, fuse elements having a large resistance value are often used.

The present invention has been made to solve the above-described problems, and an object thereof is to provide kinds of protection elements capable of reducing an internal resistance value without being affected by an intrinsic resistance value of a fuse element material.

Technical scheme for solving technical problem

The protective element according to the present invention includes an insulating substrate, a plurality of electrodes provided on the insulating substrate, an electrode filler of a low melting point metal filled between at least pairs of the electrodes, and a fuse element bridging between the at least pairs of electrodes and covering an upper portion of the electrode filler.

In the protective element, a heating element may be provided on one surface of the insulating substrate.

In the protective member, the electrode filling material may be composed of any alloys selected from the group consisting of tin-based alloys, tin-lead alloys, tin-copper alloys, tin-silver alloys, and tin-silver-copper alloys.

In the protective element, the electrode filling material may be composed of any kinds of metal materials selected from the group consisting of a metal material filled with a solder paste formed, a metal material filled with a solder ball formed, and a metal material filled by partial plating.

In the protective element, the fuse element may be composed of any kinds of alloys selected from the group consisting of tin-based alloys, tin-lead alloys, tin-copper alloys, tin-silver alloys, and tin-silver-copper alloys.

In the protection element, the fuse element may be composed of a composite material in which a plurality of metal materials of different compositions are combined.

In the protective element of the present invention, the internal resistance of the protective element is reduced by providing an electrode filler in a groove-like portion formed by end faces of opposing counter electrodes and an insulating substrate surface therebetween, so as to fill a gap between the electrodes between which the fuse element is bridged, and the electrode filler is preferably formed of a material having a lower resistance than the fuse element, and as , tin or a tin-based solder material is given.

Effects of the invention

In the protection element according to the present invention, the electrode filler fills a gap (hollow space) between electrodes provided in the fuse element. This can enlarge the cross-sectional area of the current-carrying path of the fuse element, and reduce the internal resistance of the protection element. The electrode filler is made of a metal material having a melting temperature of the fuse element or lower, and therefore does not interfere with the fusing operation of the fuse element. Furthermore, the electrode filler can be made of a fusible alloy such as a solder material as it is, and a noble metal material such as pure silver or a silver alloy (high silver content alloy) can be omitted, so that it is economical.

Drawings

Fig. 1 is an exploded perspective view of embodiments of the protective element of the present invention.

Fig. 2 shows protective elements according to embodiments of the present invention, in which (a) is a plan view obtained by cutting a lid along line IIa-IIa of (b), (b) is a sectional view taken along line IIb-IIb of (a), and (c) is a bottom view.

Fig. 3 is a main part cross-sectional view of embodiments of the protection device of the present invention, in which a cover, an electrode on the rear surface of an insulating substrate, and a heat generating element are omitted.

Detailed Description

As shown in fig. 1, the protection element 10 with an electrode filler according to the present embodiment includes an insulating substrate 11, a plurality of electrodes 12a to 12g provided on the insulating substrate 11, an electrode filler 13 of a low melting point metal filled between at least pairs of the electrodes 12a to 12g and filled between the electrodes 12a and 12b and between the electrodes 12b and 12c as examples, a fuse element 14 spanning between the at least pairs of the electrodes and covering an upper portion of the electrode filler 13, an operation flux (not shown) applied to a surface of the fuse element 14, and a lid 15 covering the operation flux and the upper portion of the fuse element 14, the electrode filler 13 being made of a metal material having a melting temperature equal to or lower than a liquidus temperature of the fuse element 14.

The insulating substrate 11 may be made of any insulating material and have any composition. As a material of the insulating substrate 11, for example, plastic, glass ceramic, or the like is preferable.

The electrode 12 provided on the insulating substrate 11 may be made of any conductive material and have any composition. As the material of the electrode 12, for example, copper, silver, a copper alloy, and a silver alloy are preferable.

The electrode filler 13 may be any material or composition as long as it can fill the metal material that is formed in the gap between the electrodes 12a and 12b and the gap between the electrodes 12b and 12c and has a melting temperature equal to or lower than that of the fuse element 14. Examples of the electrode filling material 13 include a metal material filled with a solder paste formed of a tin-based alloy, a tin-lead alloy, a tin-copper alloy, a tin-silver alloy, and a tin-silver-copper alloy, a metal material filled with a solder ball formed of a tin-based alloy, a tin-lead alloy, a tin-copper alloy, a tin-silver alloy, and a tin-silver-copper alloy, and a metal material filled with a partial plating filling formed of a tin-based alloy, a tin-lead alloy, a tin-copper alloy, a tin-silver alloy, and a tin-silver-copper alloy.

The electrode filler 13 can be integrated with the fuse element 14 in accordance with the surface mounting of the protection element 10, and since the electrode filler 13 forms a sphere with the liquefied fuse element 14 when the fuse element 14 is blown, the electrode filler does not interfere with the blowing operation.

The fuse element 14 may be any material and composition as long as it is a fusible metal material, and for example, a tin-based alloy, a tin-lead alloy, a tin-copper alloy, a tin-silver-copper alloy, or the like may be suitably used as the fuse element 14, and a metal material having a single composition may be used as the fuse element 14, or a composite material may be formed by combining a plurality of metal materials having different compositions.

In the protective element 10 of the present embodiment, a heating element may be provided on one surface of the insulating substrate 11 as needed. The heat generating element is subjected to an insulating coating as required. When the heating element is not provided, the central electrode 12b connected to the fuse element 14 among the electrodes 12a, 12b, and 12c may be omitted.

The shape and material of the cover 15 are not limited as long as the cover covers the insulating substrate 11 and the upper portion of the fuse element 14 to secure a desired space. For example, a dome-shaped resin film cover, a plastic cover, a ceramic cover, or the like can be suitably used for the cover body 15.

Example 1

As shown in fig. 2 and 3, the protection element 20 with an electrode filling material of example 1 has an insulating substrate 21 of alumina ceramic. A plurality of silver alloy electrodes 22a to 22g are provided on the insulating substrate 21. On the lower surface of the insulating substrate 21, a resistance heating element 26 electrically connected to the electrode 22f and the electrode 22h is provided.

Electrode filling material 23 of 96.5Sn-3Ag-0.5Cu alloy is filled between three

electrodes

22a, 22b, 22c of the electrodes 22a to 22g, that is, between the electrode 22a and the electrode 22b and between the electrode 22b and the electrode 22 c. A fuse element 24 made of a clad material of 92Pb-Sn alloy 24a and 99.3Sn-0.7Cu alloy 24b is provided so as to span between the three

electrodes

22a, 22b, 22c and cover the upper part of the electrode filler 23.

A lid 25 made of a liquid crystal polymer is provided so as to cover the operation flux (not shown) applied to the surface of the fuse element 24, and the operation flux and the upper portion of the fuse element 24.

The electrode filler 23 is made of a metal material having a melting temperature equal to or lower than the liquidus temperature of the fuse element 24. The

electrodes

22a and 22e, 22b and 22f, 22c and 22g, and 22d and 22h are electrically connected to each other through half-through holes of silver alloy.

The surface of the resistance heating element 26 of example 1 was glazed with an insulating glass. For the purpose of comparison with the electrode-filled protective element 20 of example 1, a protective element of a comparative example was prepared using the same members and members as those of example 1 but without the electrode filling material, and the internal resistance values of the two elements were measured. The internal resistance value of the protective element 20 with the electrode filling material of example 1 was 0.45m Ω (corresponding to the rated current 25A), while the internal resistance value of the protective element of the comparative example without the electrode filling material was 0.60m Ω (corresponding to the rated current 20A). It is understood that the structure of the present embodiment reduces the internal resistance of the protection element, thereby improving the rated current value.

In the protective element with an electrode filling material according to the present embodiment, although a void may be generated at the interface between the electrode filling material and the insulating substrate by heating, the conductive path is maintained, and thus there is no problem.

The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined not by the above description but by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Industrial applicability of the invention

The protective element with the electrode filling material of the present invention can be mounted on a circuit board to be protected together with another surface-mounted component , and mounted by soldering by a reflow method or the like , and can be used as a protective device for a secondary battery such as a battery pack.

Description of the reference symbols

10. 20 protective elements, 11, 21 insulating substrates, 12, 22 electrodes, 13, 23 electrode filling materials, 14, 24 fuse elements, 15, 25 caps, 26 heating elements.

Claims

A protective element of the kind 1, , wherein,

comprising an insulating substrate, a plurality of electrodes provided on the insulating substrate, an electrode filler of a low melting point metal filled between at least pairs of electrodes among the electrodes, and a fuse element bridging between the at least pairs of electrodes and covering the upper part of the electrode filler,

the electrode filling material is made of a metal material having a melting temperature equal to or lower than a liquidus temperature of the fuse element.
2. The protective element according to claim 1,

a heating element is provided on one surface of the insulating substrate.
3. Protection element according to claim 1 or 2,

the electrode filling material is composed of any alloys selected from the group of tin-based alloys, tin-lead alloys, tin-copper alloys, tin-silver alloys, and tin-silver-copper alloys.
4. The protective element of any one of claims 1 to 3, ,

the electrode filling material is composed of any metal materials selected from the group consisting of a metal material filled with a solder paste, a metal material filled with a solder ball, and a metal material filled by partial plating.
5. The protective element of any one of claims 1 to 4, ,

the fuse element is composed of any alloys selected from the group consisting of tin-based alloys, tin-lead alloys, tin-copper alloys, tin-silver alloys, and tin-silver-copper alloys.
6. The protective element according to claim 5,

the fuse element is composed of a composite material in which a plurality of metal materials having different compositions are combined.