WO2024098788A1

WO2024098788A1 - Chip fuse and preparation method therefor

Info

Publication number: WO2024098788A1
Application number: PCT/CN2023/103563
Authority: WO
Inventors: 杨漫雪; 刘明龙
Original assignee: 南京萨特科技发展有限公司
Priority date: 2022-11-11
Filing date: 2023-06-29
Publication date: 2024-05-16
Also published as: CN115621099A

Abstract

The present invention provides a chip fuse, which comprises a housing, electrode parts located at two ends of the housing, and a fuse part located in the housing; the electrode parts and the fuse part are integrally formed by bending the same metal strip material; each electrode part comprises a long electrode part and a short electrode part; the long electrode part covers an opening or a groove at the outside of one end of the housing and enters an accommodation cavity and is connected to the electrode part, and the short electrode part covers an outer end of a bottom wall and enters through an opening into the accommodation cavity and is connected to the electrode part; at least one end of the accommodation cavity is sealed by a sealant, and an outer surface of the sealant is in contact with external air. The sealant is not in direct contact with the fuse part, thereby greatly reducing the risk of sealant aging. The present invention likewise provides a preparation method for the chip fuse.

Description

Chip fuse and preparation method thereof

Technical Field

The invention relates to a chip type fuse, in particular to a structure of a large rated current fuse with low temperature rise performance, and a method for preparing the fuse.

Background technique

With the development of industries such as power batteries and small energy storage tools, there is an increasing demand for high-current surface-mount fuse products, and their temperature rise characteristics are particularly important. Considering the structural design of the product itself, traditional tube-shell structure fuse products use lead solder and other high-temperature melting welding and similar methods to form an electrical connection between the internal metal melt and the external end cap. As the rated current of the product itself becomes higher and higher, the limitations of the structure and main performance indicators of the product obtained by welding technology, such as temperature rise, are gradually prominent, and a new product design is needed to meet this demand.

Chinese patent 201380010087.4 proposes a structural design scheme for integrally forming a metal melt and a terminal. The metal sheet is formed into a specific pattern and structure by stamping. The process mode is adopted in which the end electrodes on both sides used for welding and the fuse in the middle for protection are integrally formed on the same metal sheet. The external electrodes on both sides are overlapped to the bottom of a square insulating shell with an open end. The fuse is placed inside the insulating shell, and the open end of the insulating shell is sealed by silicone resin or epoxy resin. The advantage of this structure is mainly to reduce the contact resistance between the metal melt and the end electrode, but the disadvantage is also obvious. Because the silicone resin is at the bottom of the product, it is difficult to dissipate heat, and it is in direct contact with the metal sheet of the fuse, which is easy to cause heat accumulation. The sealing resin will age with the increase of product use time and temperature, thereby causing the end electrode and fuse to fall off.

Therefore, a new technical solution is needed to solve the above technical problems.

Summary of the invention

In view of the above problems, the present invention provides a chip fuse to solve the problem that when the electrode part and the fuse body are integrally formed by metal sheets, the sealant at the end of the shell ages and causes the electrode part to fall off easily.

The invention also provides a method for preparing the chip type fuse.

In order to achieve the above-mentioned objective functions, the chip fuse of the present invention adopts the following technical solutions:

A chip fuse comprises a shell, electrode parts located at both ends of the shell, and a fuse body located in the shell; the electrode parts and the fuse body are formed by bending the same metal strip as a whole; the shell comprises a top wall, a bottom wall, and two side walls, the top wall, the bottom wall, and the two side walls form a receiving cavity, and the two ends of the shell are provided with openings and/or openings. The electrode parts at both ends include a long electrode part and a short electrode part, the long electrode part covers the opening or slot outside one end of the shell and enters the receiving cavity to connect with the electrode part, and the short electrode part covers the outer end of the bottom wall and enters the receiving cavity from the opening to connect with the electrode part; at least one end of the receiving cavity is sealed by a sealant, and the outer surface of the sealant is in contact with the external air.

Furthermore, one end of the shell is provided with an end wall and the other end is an opening, the end wall is provided with a groove connected to the receiving cavity, the long electrode part covers the end wall and the outside of the groove and extends from the groove into the receiving cavity to connect with the electrode part; the electrode part extends obliquely downward in the receiving cavity from the position where it is connected with the long electrode part and is connected with the short electrode part; and a sealant is provided at the opening and the groove to seal the opening and the groove.

Furthermore, the opening area is the same as the cross-sectional area of the receiving cavity; the short electrode portion covers the outer end of the bottom wall and bends to extend to the bottom of the bottom wall; the cross-sectional area of the groove is smaller than the cross-sectional area of the receiving cavity, and the long electrode portion covers the end wall and bends to extend from the outside of the end wall to the bottom of the bottom wall.

Furthermore, the accommodating cavity is filled with arc-extinguishing material that wraps the fuse body.

Furthermore, both ends of the shell are provided with openings, one end of the bottom wall is provided with a concave portion inclined inwardly to form a chamfer, and the long electrode portion is provided with an elastic protrusion bent inwardly, and the protrusion abuts against the concave portion; the long electrode portion completely covers and closes the opening and extends closely from the inner surface of the top wall into the accommodating cavity to be connected to the fuse body.

Furthermore, the opening area of one end of the concave portion provided on the bottom wall of the shell is larger than the cross-sectional area of the accommodating cavity; the opening area of the other end of the shell is the same as the cross-sectional area of the accommodating cavity.

Furthermore, the opening at the end where the long electrode portion is located is not provided with sealant, and the end where the short electrode portion is located is covered with sealant for sealing.

Beneficial effects:

Since the present invention adopts the above technical scheme, it has the following advantages: in the structure of the chip-type fuse described in the present invention, the metal strip is firmly fixed to the two ends of the shell by diagonal bending, thereby avoiding the potential risk of the insulating shell falling off of similar products in the industry; in addition, in the structure of the chip fuse described in the present invention, at least one surface of the sealant is in contact with the air and is not in direct contact with the fuse body, thereby greatly reducing the risk of aging of the sealant and improving the service life of the product.

The present invention also provides a method for preparing the chip-type fuse, comprising the following steps:

Step (1): stamping a metal strip into a fuse body;

Step (2): Insert the metal strip formed by punching the fuse body into the receiving cavity through the slot of the insulating shell. Inside, and out through the open side at the other end;

Step (3): firstly bend the metal strip inserted into the receiving cavity downward along the end surface of the lower side wall to form a short electrode portion, and then bend it inward along the bottom surface of the bottom wall to form a welding surface, so that the metal strip is completely fixed to the shell;

Step (4): Place the end of the shell with the welding surface downward, use a glue dispenser to dispense glue to seal the slot of the shell, and allow the sealant to cure;

Step (5): With the opening of the shell facing upward and the sealed surface facing downward, fill the receiving cavity with arc extinguishing material and compact it;

Step (6): The opening is sealed by filling the sealant on the surface of the arc extinguishing material and then solidified.

The present invention also provides another method for preparing the chip-type fuse, comprising the following steps:

Step (1): stamping a metal strip to form a fuse body; stamping and bending the metal strip to form a protrusion at a position required by the design;

Step (2): passing the metal strip material punched to form the fuse body into the receiving cavity through the slot of the insulating housing and out from the other end opening;

Step (3): first tighten the metal strip so that the raised portion on the metal strip fits tightly against the concave portion of the shell, and the upper end of the metal strip fits tightly against the inner surface of the top wall by the elastic force of the raised portion, and then both ends of the metal strip are simultaneously bent toward the bottom of the bottom wall to form a welding surface, and at the same time, one end of the shell is sealed with the width of the metal strip;

Step (4): With the opening of the shell facing upward and the sealed surface facing downward, fill the receiving cavity with arc extinguishing material and compact it;

Step (5): The opening is sealed by filling the sealant on the surface of the arc extinguishing material and then solidified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a longitudinal cross-sectional view of a chip fuse according to a first embodiment of the present invention;

FIG2 is a three-dimensional structural diagram of an insulating housing for a fuse according to Embodiment 1 of the present invention;

FIG3 is a flow chart of a method for preparing a fuse according to Embodiment 1 of the present invention;

FIG4 is a longitudinal cross-sectional view of the chip fuse according to the second embodiment of the present invention;

5 is a schematic diagram of the metal strip bent to form the electrode portion and the fuse portion after being assembled with the housing in the second embodiment of the present invention;

6 is a longitudinal sectional view of the insulating housing for the fuse according to the second embodiment of the present invention;

7 is a cross-sectional view of the melt penetration structure in the fuse according to the second embodiment of the present invention;

FIG. 8 is a schematic diagram of strip stamping in the fuse production process described in the second embodiment of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below:

The present invention is described in detail below with reference to the accompanying drawings and embodiments.

Embodiment 1:

As shown in FIG. 1 to FIG. 3 , this embodiment provides a chip fuse, comprising: an insulating housing 1, a metal strip 2, an arc extinguishing material 3 and a sealant 4. Among them:

The insulating shell 1 includes a top wall, a bottom wall, and two side walls, which enclose a receiving cavity. One end of the receiving cavity is fully open, and the other end is an end wall. A set of transversely extending slots 11 are opened on the end wall, and the slots 11 are connected to the receiving cavity. The insulating shell 1 is a tubular structure, and is formed by high-temperature sintering of ceramic materials such as alumina by hot die casting and other molding processes. It has high thermal conductivity, mechanical strength and heat resistance; it can also be injection molded by high-temperature resistant resins such as epoxy resin and polyphenylene sulfide. The interior of the insulating shell 1 can be a circular cross-section, a square cross-section or other irregular cross-sections.

The metal strip 2 includes an end electrode portion 21 and a fuse body portion 22 which are integrally formed, and are made of metal materials such as copper, silver or their alloys, and are silver-plated, nickel-plated or tin-plated on the surface. The metal strip 2 adopts a diagonally inclined structural design, and the end electrode portions 21 are respectively fixed on the two surfaces of the opening of the insulating shell 1, that is, the fuse body portion 22 of the metal strip 2 is obliquely placed inside the tubular insulating shell 1, and the end electrode portion 21 is bent downward along the two opposite openings or slotted end surfaces of the insulating shell 1 to form a fuse side electrode 211, and is bent toward the inside along the outer surface of the side wall of the insulating shell 1 to form a welding surface electrode 212 of the fuse.

The arc extinguishing material 3 is solid particles of quartz sand or gas-generating arc extinguishing material with a mesh size of 50 to 150; the arc extinguishing material 3 is filled in the internal cavity of the insulating shell 1 and vibrated, so that it is tightly wrapped around the fuse body 22 in the metal strip 2, which plays a role in reducing the temperature rise during normal use of the product and quickly extinguishing the arc when the product is abnormally blown.

The sealant 4 is high temperature resistant silica gel or silicone glue, which is used to seal the opening part of the insulating shell 1. It is in close contact with the surface of the arc extinguishing material 3 and is separated from the fuse body 22 to prevent the fuse body 22 from directly and continuously heating it, thereby greatly improving its heat dissipation and avoiding the sealant 4 from falling off due to aging of the sealant 4 caused by internal accumulated heat when the product works at abnormal current for a long time, thereby greatly extending the service life of the product.

As shown in FIG3 , the method for preparing the chip fuse according to the first embodiment of the present invention includes the following steps:

Step (1): stamping the metal strip 2 into a fuse body 22 as required;

Step (2): inserting the metal strip 2 punched to form the fuse body 22 into the insulating housing 1 from the semi-enclosed opening 11 side of the insulating housing 1 and out from the fully-opened side;

Step (3): The metal strip 2 inserted into the insulating housing 1 is first bent downward along the end surface of the insulating housing 1 to form a side electrode 211 of the fuse, and then bent inward along the bottom side wall of the insulating housing 1 to form a welding surface electrode 212 of the fuse, so that the metal strip 2 is completely fixed to the insulating housing 1;

Step (4): Place the side wall of the insulating housing 1 with the welding surface electrode 212 downward, use a glue dispenser to dispense glue to seal the uncompletely sealed position on the semi-enclosed surface of the insulating housing 1, and use a suitable process to cure the sealant;

Step (5): With the opening surface of the insulating housing 1 facing upward and the sealed surface facing downward, fill the insulating housing 1 with quartz sand as the arc extinguishing material 3 by means of a vibrating sand process, and compact the quartz sand. The quartz sand has a mesh size of 50 to 150, and the filling height is such that at least the fuse body 22 in the metal strip 2 is submerged, and the upper limit is such that the sealant 4 has a sufficient bonding contact area to provide the required bonding strength;

Step (6): fill the surface of the quartz sand arc-extinguishing material 3 with sealant 4 by a glue dispensing machine and solidify it, thereby obtaining the chip fuse described in the first embodiment of the present invention.

Embodiment 2:

As shown in FIG. 4 to FIG. 8, another structural form of the chip fuse of the present invention is shown. Compared with the first embodiment, the main difference is that both ends of the insulating shell 1 of the chip fuse are fully open, which is similar to the ceramic tube structure used in the traditional fuse, as shown in FIG. 6. An open end face of the insulating shell 1 is designed with a larger chamfered concave portion 12 as the inner side surface that contacts the welding surface electrode of the fuse. Accordingly, the metal strip 2 is stamped and bent at the lower part of the side electrode position to form an elastic protrusion 23, and the protrusion 23 abuts against the concave portion 12. The long electrode portion 211 completely covers and closes the opening and is close to the inner surface of the top wall. The long electrode portion 211 is fixed between the top wall and the concave portion 12 through the elastic force of the elastic protrusion 23 from the inner surface of the top wall, and at the same time limits the position of the metal strip 2 when the melt penetrates, so that the metal strip 2 can be tightened more conveniently, as shown in FIG. 7. As shown in FIG6 , due to the provision of the concave portion 12, the opening area of the insulating housing 1 at one end of the bottom wall where the concave portion is provided is larger than the cross-sectional area of the receiving cavity; the opening area of the other end of the insulating housing 1 is the same as the cross-sectional area of the receiving cavity. Since the long electrode portion 211 serves as both an electrode and a closed portion that covers and closes the opening at one end of the insulating housing 1, the opening at the end where the long electrode portion 211 is located is not provided with a sealant, and the end where the short electrode portion 213 is located is covered with a sealant seal 4.

The method for preparing the chip fuse according to the second embodiment of the present invention comprises the following steps:

Step (1): stamping the metal strip 2 into the fuse body 22 as required, and punching the fuse body 22 at the required position. The protrusion 23 is formed by pressing and bending, and the downward bending distance of the protrusion 23 is equivalent to the inner cavity height of the insulating housing 1;

Step (2): passing the metal strip 2 punched to form the fuse body 22 through the interior of the insulating housing 1;

Step (3): first tighten the metal strip 2 inserted into the insulating housing 1 so that the raised portion 23 on the metal strip 2 is closely attached to the concave portion 12 of the insulating housing 1, and then simultaneously bend both ends of the metal strip 2 toward the inner side of the insulating housing 1 to form a welding surface electrode 212, and at the same time seal one end of the insulating housing 1 with the width of the metal strip 2;

Step (4): With the opening surface of the insulating housing 1 facing upward and the closed surface facing downward, the insulating housing 1 is filled with quartz sand as the arc extinguishing material 3 by means of a sand vibrating process, etc., and the quartz sand is vibrated to compact the inside. The quartz sand has a mesh size of 50 to 150, and the filling height is such that at least the fuse body 22 in the metal strip 2 is submerged, and the upper limit is such that the sealant 4 has a sufficient bonding contact area to provide the required bonding strength;

Step (5): Fill the surface of the quartz sand arc-extinguishing material 3 with sealant 4 by a glue dispensing machine and solidify it, thereby obtaining the chip fuse described in the second embodiment of the present invention.

The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above-mentioned technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

A chip fuse comprises a shell, electrode parts located at both ends of the shell, and a fuse body located in the shell; the electrode parts and the fuse body are formed by bending the same metal strip in one piece; the shell comprises a top wall, a bottom wall, and two side walls, the top wall, the bottom wall, and the two side walls form a receiving cavity, and openings and/or slots are provided at both ends of the shell;

The electrode parts at both ends include a long electrode part and a short electrode part. The long electrode part covers the opening or groove on the outside of one end of the shell and enters the receiving cavity to be connected with the electrode part. The short electrode part covers the outer end of the bottom wall and enters the receiving cavity from the opening to be connected with the electrode part. At least one end of the receiving cavity is sealed by a sealant, and the outer surface of the sealant is in contact with the external air.
The chip-type fuse according to claim 1 is characterized in that: one end of the shell is provided with an end wall and the other end is an opening, the end wall is provided with a slot connected to the receiving cavity, the long electrode portion covers the end wall and the outside of the slot and extends from the slot into the receiving cavity to connect with the electrode portion; the electrode portion extends obliquely downward in the receiving cavity from the position where it is connected to the long electrode portion and is connected to the short electrode portion; a sealant is provided at the opening and the slot to seal the opening and the slot.
The chip-type fuse according to claim 2 is characterized in that: the opening area is the same as the cross-sectional area of the receiving cavity; the short electrode portion covers the outer end of the bottom wall and bends to extend to the bottom of the bottom wall; the cross-sectional area of the groove is smaller than the cross-sectional area of the receiving cavity, and the long electrode portion covers the end wall and bends to extend from the outside of the end wall to the bottom of the bottom wall.
The chip fuse according to claim 2 or 3 is characterized in that the accommodating cavity is filled with arc extinguishing material that wraps the fuse body.
The chip-type fuse according to claim 1 is characterized in that: both ends of the shell are provided with openings, one end of the bottom wall is provided with a concave portion inclined inwardly to form a chamfer, and the long electrode portion is provided with an elastic protrusion bent inwardly, and the protrusion abuts against the concave portion; the long electrode portion completely covers and closes the opening and is in close contact with the inner surface of the top wall, and the long electrode portion extends from the inner surface of the top wall into the accommodating cavity to connect with the fuse body.
The chip fuse according to claim 5 is characterized in that: the opening area of one end of the shell body where the concave portion is arranged on the bottom wall is larger than the cross-sectional area of the accommodating cavity; the opening area of the other end of the shell body is the same as the cross-sectional area of the accommodating cavity.
The chip fuse according to claim 5 or 6 is characterized in that: the opening at the end where the long electrode portion is located is not provided with sealant, and the end where the short electrode portion is located is covered with sealant for sealing.
The chip fuse according to claim 7 is characterized in that: the receiving cavity is filled with There is arc extinguishing material wrapped around the fuse body.
A method for preparing a chip fuse according to any one of claims 2 to 4, characterized in that it comprises the following steps:

Step (1): stamping a metal strip into a fuse body;

Step (2): passing the metal strip material punched to form the fuse body into the receiving cavity through the slot of the insulating housing and out from the other end opening;

Step (3): firstly bend the metal strip inserted into the receiving cavity downward along the end surface of the lower side wall to form a short electrode portion, and then bend it inward along the bottom surface of the bottom wall to form a welding surface, so that the metal strip is completely fixed to the shell;

Step (4): Place the end of the shell with the welding surface downward, use a glue dispenser to dispense glue to seal the slot of the shell, and allow the sealant to cure;

Step (5): With the opening of the shell facing upward and the sealed surface facing downward, fill the receiving cavity with arc extinguishing material and compact it;

Step (6): The opening is sealed by filling the sealant on the surface of the arc extinguishing material and then solidified.
A method for preparing a chip fuse according to any one of claims 5 to 8, characterized in that it comprises the following steps:

Step (1): stamping a metal strip to form a fuse body; stamping and bending the metal strip to form a protrusion at a position required by the design;

Step (2): passing the metal strip material punched to form the fuse body into the receiving cavity through the slot of the insulating housing and out from the other end opening;

Step (3): first tighten the metal strip so that the raised portion on the metal strip fits tightly against the concave portion of the shell, and the upper end of the metal strip fits tightly against the inner surface of the top wall by the elastic force of the raised portion, and then both ends of the metal strip are simultaneously bent toward the bottom of the bottom wall to form a welding surface, and at the same time, one end of the shell is sealed with the width of the metal strip;

Step (4): With the opening of the shell facing upward and the sealed surface facing downward, fill the receiving cavity with arc extinguishing material and compact it;

Step (5): The opening is sealed by filling the sealant on the surface of the arc extinguishing material and then solidified.