CN100448133C - Overcurrent protection device and manufacturing method thereof - Google Patents

Abstract

An over-current protection device and a manufacturing method thereof, the over-current protection device comprises: at least one positive temperature coefficient element, which comprises a positive temperature coefficient material layer and two electrode layers arranged on two sides of the positive temperature coefficient material layer in an overlapping way; at least one heat dissipation layer; at least one connecting glue layer for connecting the at least one positive temperature coefficient element and the at least one heat dissipation layer and serving as a heat conduction medium therebetween; at least two isolation layers are used for separating the heat dissipation layer, the connection adhesive layer and the electrode layer into two parts so as to block the electrical connection. The invention can quickly dissipate the heat generated by the over-current protection device, so as to be suitable for electronic devices which are increasingly miniaturized.

Description

Overcurrent protection device and manufacturing method thereof

【Technical field】

The invention relates to an overcurrent protection device and a manufacturing method thereof, in particular to an overcurrent protection device with rapid heat dissipation effect and a manufacturing method thereof.

【Background technique】

With the widespread application of portable electronic products (such as mobile phones, notebook computers, portable cameras and personal digital assistants, etc.), in order to prevent the circuit from over-current or over-temperature over-current Protective gear has been clearly taken seriously.

It is known that the resistance value of a positive temperature coefficient (Positive Temperature Coefficient, PTC) element responds quite sensitively to temperature changes. When the PTC element is in normal use, its resistance can maintain a very low value so that the circuit can operate normally. However, when the temperature rises to a critical temperature due to overcurrent or overheating, its resistance value will instantly jump to a high resistance state (for example, above 10 ⁴ ohm) to counteract the excessive current in reverse to achieve protection purpose of batteries or circuit components. Therefore, the PTC element has been integrated into various circuit elements to prevent overcurrent damage.

FIG. 1 shows a known overcurrent protection device 10 , which includes a positive temperature coefficient material layer 101 , two electrode layers 102 , two isolation layers 103 , two conductive pillars 104 and two welding electrode layers 105 . The two electrode layers 102 are stacked on the upper and lower surfaces of the positive temperature coefficient material layer 101 , and the welding electrode layer 105 covers the surface of the electrode layer 102 . The conductive column 104 penetrates the positive temperature coefficient material layer 101 and the two electrode layers 102 to electrically connect the two electrode layers 102 and the surface welding electrode layer 105 . The isolation layer 103 separates the electrode layer 102 into left and right parts, so as to block their electrical connection. The overcurrent protection device 10 forms left and right electrode terminals, which can be respectively connected to circuits or components to be protected by wires (not shown).

With the current trend of miniaturization of electronic devices, heat dissipation of components has become an important design consideration. If the heat cannot be effectively dissipated, the service life and reliability of the overcurrent protection device will be greatly reduced.

【Content of invention】

The purpose of the present invention is to provide an over-current protection device and its manufacturing method, which can accelerate the dissipation of heat generated by the over-current protection device, so as to be suitable for increasingly miniaturized electronic devices.

In order to achieve the above object, the present invention provides an overcurrent protection device, characterized in that: it comprises:

At least one positive temperature coefficient element, which includes a positive temperature coefficient material layer and two electrode layers stacked on both sides of the positive temperature coefficient material layer;

at least one heat dissipation layer;

at least one adhesive layer connecting the at least one positive temperature coefficient element and at least one heat dissipation layer, and serving as a heat conduction medium between the positive temperature coefficient element and the heat dissipation layer;

At least two isolation layers separate the heat dissipation layer, the bonding adhesive layer and the electrode layer into two parts, so as to block their electrical connection.

The overcurrent protection device is characterized in that: the positive temperature coefficient material layer is composed of polymer positive temperature coefficient material.

The overcurrent protection device is characterized in that: the material of the heat dissipation layer is selected from aluminum, copper or alloys thereof.

The overcurrent protection device is characterized in that: the connecting glue layer is composed of silver glue or copper glue.

The overcurrent protection device is characterized in that: the connecting glue layer is made of resin or epoxy plastic.

The overcurrent protection device is characterized in that: the isolation layer is composed of solder resist.

The above-mentioned overcurrent protection device is characterized in that it further includes at least one conductive column for electrically connecting the two electrode layers.

The overcurrent protection device is characterized in that: the conductive column is made of silver or copper.

The above-mentioned overcurrent protection device is characterized in that it further includes two welding electrode layers, which are arranged on the surface of the electrode layer or the heat dissipation layer.

The overcurrent protection device is characterized in that: the material of the welding electrode layer is selected from tin, lead or alloys thereof.

The above-mentioned overcurrent protection device is characterized in that it further includes two welding electrode layers, which are arranged on the surface of the electrode layer or the heat dissipation layer, and the conductive column is further connected to the two welding electrode layers.

The present invention also provides a method for manufacturing an overcurrent protection device, which is characterized in that it includes the following steps:

(a) providing at least one positive temperature coefficient element, which is composed of a positive temperature coefficient material layer stacked between two electrode layers;

(b) forming at least one adhesive layer on the surface of the at least one positive temperature coefficient element;

(c) forming at least one heat dissipation layer on the surface of the at least one adhesive layer;

(d) At least two isolation layers are formed in the heat dissipation layer, the adhesive layer and the electrode layer for blocking their electrical connection.

The manufacturing method of the overcurrent protection device is characterized in that it further includes a step of manufacturing at least one conductive column to connect the two electrode layers.

The manufacturing method of the overcurrent protection device is characterized in that it further includes the step of manufacturing two welding electrode layers on the surface of the heat dissipation layer or the electrode layer.

The manufacturing method of the overcurrent protection device is characterized in that it further includes a step of manufacturing two welding electrode layers on the surface of the heat dissipation layer or the electrode layer, and the conductive column is further connected to the two welding electrode layers.

The manufacturing method of the overcurrent protection device is characterized in that: the conductive column is made by electroplating or filling conductive paste.

The manufacturing method of the overcurrent protection device is characterized in that: the isolation layer is formed by etching, laser, cutting or milling, and filling the opening with insulating material.

To sum up, the overcurrent protection device disclosed by the present invention includes at least one positive temperature coefficient element, at least one heat dissipation layer, at least one bonding adhesive layer, and at least two isolation layers. The at least one positive temperature coefficient element is composed of a positive temperature coefficient material layer stacked between two electrode layers. The at least one bonding glue layer is arranged between the at least one positive temperature coefficient element and the at least one heat dissipation layer, and is used for connecting the two and serving as a heat conduction medium between them. The at least two isolation layers separate the heat dissipation layer, the bonding adhesive layer and the electrode layer into two parts to block their electrical connection.

The overcurrent protection device may further include at least one conductive column for connecting the two electrode layers to realize electrical conduction. In addition, two welding electrode layers can be covered on the surface of the electrode layer or heat dissipation layer to prevent oxidation.

The function of the heat dissipation layer is similar to a heat sink, which can quickly dissipate the heat generated by the positive temperature coefficient element, so as to prolong the service life of the overcurrent protection device, improve its reliability, and expand its application range.

The overcurrent protection device of the present invention can be manufactured mainly according to the following steps (a) to (d). In step (a), at least one positive temperature coefficient element is provided, which is formed by stacking a positive temperature coefficient material layer between two electrode layers. In step (b), at least one bonding adhesive layer is formed on the surface of the at least one positive temperature coefficient element. In step (c), at least one heat dissipation layer is formed on the surface of the at least one adhesive layer. In step (d), at least two isolation layers are formed in the heat dissipation layer, the adhesive layer and the electrode layer for blocking their electrical connection.

【Description of drawings】

1 is a schematic diagram of a known overcurrent protection device;

Fig. 2 (a) is the perspective view of the overcurrent protection device of the first preferred embodiment of the present invention;

Fig. 2 (b) is a sectional view along section line 1-1 in Fig. 2 (a);

3 is a cross-sectional view of an overcurrent protection device according to a second preferred embodiment of the present invention;

4 is a cross-sectional view of an overcurrent protection device according to a third preferred embodiment of the present invention;

5 is a cross-sectional view of an overcurrent protection device according to a fourth preferred embodiment of the present invention;

6(a) to 6(g) illustrate the manufacturing process of the overcurrent protection device according to the fifth preferred embodiment of the present invention.

Explanation of component symbols in the figure:

【Detailed ways】

The main technical means of the invention is to add a heat dissipation layer in the overcurrent protection device to achieve the purpose of accelerating heat dissipation. Hereinafter, several examples will be used for illustration.

Referring to Fig. 2 (a) and 2 (b), wherein Fig. 2 (a) is the perspective view of the overcurrent protection device of the first preferred embodiment of the present invention, and Fig. 2 (b) is along 1 in Fig. 2 (a) Sectional drawing of -1 section line. An overcurrent protection device 20 includes a positive temperature coefficient material layer 201, two electrode layers 202, a bonding adhesive layer 203, a heat dissipation layer 204, two isolation layers 207 and 208, two conductive pillars 209 and two welding electrode layers 205 and 206 . The positive temperature coefficient material layer 201 is stacked between the two electrode layers 202 to form a positive temperature coefficient element 21 similar to a sandwich structure. The positive temperature coefficient material layer 201 may be composed of a polymer positive temperature coefficient material (Polymer Positive Temperature Coefficient, PPTC). The bonding glue layer 203 is interposed between the positive temperature coefficient element 21 and the heat dissipation layer 204 for connecting the two and serving as a heat conduction medium therebetween. The bonding adhesive layer 203 can be made of conductive or non-conductive materials, such as conductive silver glue, copper glue or non-conductive resin, epoxy plastic and the like. The heat dissipation layer 204 is disposed on the surface of the bonding adhesive layer 203 and can be made of aluminum, copper metal or alloys thereof with good heat dissipation performance. When over-current or over-temperature occurs, the heat generated by the positive temperature coefficient element 21 can be conducted to the heat dissipation layer 204 through the bonding adhesive layer 203 to be quickly dissipated. The isolation layer 207 separates the heat dissipation layer 204 , the bonding adhesive layer 203 and the electrode layer 202 above the PTC material layer 201 into two parts to block the electrical connection between the two parts. The isolation layer 208 separates the electrode layer 202 below the positive temperature coefficient material layer 201 into two parts, and its purpose is also to block the electrical connection. The conductive pillar 209 can be formed by mechanical drilling or laser penetration, and then made by electroplating copper, silver or filling conductive paste (such as copper paste or silver paste, etc.). The welding electrode layer 205 covers the surface of the heat dissipation layer 204, and the welding electrode layer 206 covers the surface of the electrode layer 202 below the positive temperature coefficient material layer 201, so that the overcurrent protection device 20 can be connected to The circuit or component to be protected. The welding electrode layers 205 and 206 are generally made of tin, lead or their alloys which are not easily oxidized, so the heat dissipation layer 204 and the electrode layer 202 can be prevented from being oxidized.

In this embodiment, although the bonding adhesive layer 203 can be made of non-conductive materials, this will cause the welding electrode layer 205 to be difficult to electrically connect to the positive temperature coefficient element 21, so that the wire (not marked in the figure) can only be welded To the welding electrode layer 206, thus reducing the flexibility in fabrication. However, when the bonding adhesive layer 203 is made of non-conductive material, and two wires (not shown) are respectively connected to the left and right parts of the welding electrode layer 206, even if there is no conductive post 209 on the left, the two The wire can also be electrically connected in series with the positive temperature coefficient element 21 to achieve a protective effect, so the conductive column 209 on the left can be omitted.

The thermal conductivity, heat capacity and electrical conductivity of aluminum and copper metals are shown in Table 1. It can be seen from Table 1 that both aluminum and copper have good heat dissipation and electrical conductivity properties, and aluminum and copper are cheaper than silver, so the heat dissipation layer 204 made of aluminum, copper or their alloys (aluminum-copper alloy) can achieve The purpose of dissipating the heat generated by the positive temperature coefficient element 21 quickly.

Table I

aluminum copper Electrical conductivity (siemens/m) 0.377*106 0.596*106 Heat capacity (J/Kg℃) 910 390 Thermal conductivity (W/m℃) 160 200

Because the three-dimensional appearance of the overcurrent protection device in other embodiments of the present invention is similar to the structure shown in FIG. 2( a ), the only difference is the change of the internal structure and thickness. Therefore, the following embodiments will omit to show their three-dimensional views, and only show them in cross-sectional views.

FIG. 3 is a cross-sectional view of an overcurrent protection device according to a second preferred embodiment of the present invention. An overcurrent protection device 30 includes a positive temperature coefficient material layer 301, two electrode layers 302, a bonding adhesive layer 303, a heat dissipation layer 304, two isolation layers 307 and 308, two conductive pillars 309 and two welding electrode layers 305 and 306 . The positive temperature coefficient material layer 301 is stacked between the two electrode layers 302 to form a positive temperature coefficient element 31 . Compared with the overcurrent protection device 20 of the first preferred embodiment, the overcurrent protection device 30 of this embodiment extends the conductive column 309 to connect the upper and lower welding electrode layers 305 , 306 . In this way, even if the connecting glue layer 303 is made of non-conductive material, it can electrically connect the PTC element 31 and the welding electrode layer 305 . In addition, as far as the manufacturing process is concerned, in this embodiment, the bonding adhesive layer 303 and the heat dissipation layer 304 can be laminated on the positive temperature coefficient device 31 before drilling and manufacturing the conductive pillar 309, thereby increasing the flexibility of manufacturing.

FIG. 4 is a cross-sectional view of an overcurrent protection device according to a third preferred embodiment of the present invention, which discloses an overcurrent protection device including double heat dissipation layers. An overcurrent protection device 40 includes a positive temperature coefficient material layer 401 , two electrode layers 402 , two bonding glue layers 403 , two heat dissipation layers 404 , two isolation layers 407 , two conductive pillars 409 and two welding electrode layers 405 . The positive temperature coefficient material layer 401 is stacked between the two electrode layers 402 to form a positive temperature coefficient element 41 . The two bonding adhesive layers 403 , the two heat dissipation layers 404 and the two welding electrode layers 405 are sequentially stacked on the upper and lower surfaces of the PTC element 41 . Compared with the overcurrent protection device 20 of the first preferred embodiment, the overcurrent protection device 40 of this embodiment mainly adds a heat dissipation layer 404 on one side of the positive temperature coefficient element 41, so that the positive temperature coefficient element 41 can be The heat dissipation efficiency is greatly improved through the heat dissipation layers 404 located on both sides thereof.

FIG. 5 is a cross-sectional view of an overcurrent protection device according to a fourth preferred embodiment of the present invention. An overcurrent protection device 50 includes a positive temperature coefficient material layer 501 , two electrode layers 502 , two bonding glue layers 503 , two heat dissipation layers 504 , two isolation layers 507 , two conductive pillars 509 and two welding electrode layers 505 . The positive temperature coefficient material layer 501 and the two electrode layers 502 form a positive temperature coefficient element 51 . Compared with the overcurrent protection device 40 of the third preferred embodiment, the overcurrent protection device 50 of this embodiment extends the conductive column 509 to connect the upper and lower welding electrode layers 505, 506, and its advantages are similar to those of the second embodiment. The example overcurrent protection device 30 is the same and will not be described again.

In addition, the overcurrent protection device of the present invention can also include several positive temperature coefficient elements, and the resistance value can be reduced by utilizing their parallel connection characteristics. An overcurrent protection device including two positive temperature coefficient elements is disclosed below, and the manufacturing process of the overcurrent protection device of the present invention is disclosed through this example.

6(a) to 6(g) illustrate the fabrication process of the overcurrent protection device according to the fifth preferred embodiment of the present invention. Referring to FIG. 6( a ), firstly, two PTC elements 61 are provided. Each PTC element 61 is composed of a PTC material layer 601 stacked between two electrode layers 602 . Next, a notch 62 is cut out in the two electrode layers 602 by means of etching or the like, as shown in FIG. 6( b ). Please note that for simplicity of the drawings, only one positive temperature coefficient element 61 is shown in FIGS. 6(a) and 6(b) as a representative. Referring to FIG. 6( c ), the two PTC devices 61 are laminated with a bonding glue layer 603 , and the gap 62 is filled with insulating materials such as solder resist to form isolation layers 607 and 608 . Referring to FIG. 6( d ), two heat dissipation layers 604 are respectively bonded to the exposed electrode layer 602 by using two connecting glue layers 603 . Referring to FIG. 6( e ), two through holes 612 are formed through the two positive temperature coefficient elements 61 , the two heat dissipation layers 604 and the connecting glue layer 603 therebetween by means of mechanical or laser drilling. In addition, two openings 613 are cut out from the heat dissipation layer 604 , the bonding glue layer 603 and the isolation layer 608 by means of etching, laser, cutting or milling. Referring to FIG. 6( f ), two conductive pillars 609 are fabricated by means of electroplating or filled with conductive paste, and solder resist is filled into the opening 613 to form two isolation layers 610 . Referring to FIG. 6( g ), finally, the surface of the heat dissipation layer 604 is covered with a welding electrode layer 605 .

In fact, the overcurrent protection devices disclosed in the above-mentioned first to fourth preferred embodiments can also be manufactured using the same principle as that of the fifth preferred embodiment, only the manufacturing sequence is different, for example, the order of manufacturing the conductive pillars and the heat dissipation layer is different. . In addition, the overcurrent protection devices in the above diagrams all include two conductive posts, but in fact, if the connecting adhesive layer is made of conductive materials, and the external wires are connected to the welding electrode layers on both sides of the positive temperature coefficient element, even if omitted The two conductive pillars and the wire can also be electrically connected in series with the positive temperature coefficient element to achieve a protective effect.

Although those skilled in the art may have the possibility to reverse the order of the above-mentioned manufacturing steps according to different structural needs, as long as the principle of the present invention is also applied, it is still covered by the technical scope of the present invention.

The above-mentioned welding electrode layer is not an essential element of the overcurrent protection device of the present invention. If the overcurrent protection device is applied in a vacuum or other environments without oxidation concerns, the welding electrode layer can be omitted.

The technical content and technical features of the present invention have been disclosed above, but those skilled in the art may still make various substitutions and modifications based on the teaching and disclosure of the present invention without departing from the spirit of the present invention. Therefore, the protection scope of the present invention should not be limited to the contents disclosed in the embodiments, but should include various replacements and modifications without departing from the present invention.

Claims (17)

1. overcurrent protective device, it is characterized in that: it comprises:

At least one positive temperature coefficient element, one first electrode layer and a second electrode lay that it comprises a PTC material layer and is stacked at these PTC material layer both sides;

At least one heat dissipating layer;

At least one binding glue-line links this at least one positive temperature coefficient element and at least one heat dissipating layer, and as the heat-conduction medium between positive temperature coefficient element and the heat dissipating layer;

One first separator, with this heat dissipating layer, link glue-line and first electrode layer is divided into two parts separately, with blocking-up respectively this heat dissipating layer, link being electrically connected between two parts of the glue-line and first electrode layer;

One second separator is divided into two parts with this second electrode lay, with being electrically connected between two parts of blocking this second electrode lay.

2. overcurrent protective device as claimed in claim 1 is characterized in that: this PTC material layer is made up of the high molecular positive temperature coefficient material.

3. overcurrent protective device as claimed in claim 1 is characterized in that: the material of this heat dissipating layer is to be selected from aluminium or copper or aluminium alloy or copper alloy.

4. overcurrent protective device as claimed in claim 1 is characterized in that: this binding glue-line is made up of elargol or copper glue.

5. overcurrent protective device as claimed in claim 1 is characterized in that: this binding glue-line is made up of resin or epoxy plastics.

6. overcurrent protective device as claimed in claim 1 is characterized in that: this first separator and second separator are made up of anti-solder flux.

7. overcurrent protective device as claimed in claim 1 is characterized in that: it comprises at least one conductive pole in addition, is used to be electrically connected this first electrode layer and the second electrode lay.

8. overcurrent protective device as claimed in claim 7 is characterized in that: this conductive pole is made up of silver or copper.

9. overcurrent protective device as claimed in claim 1 is characterized in that: it comprises two welding electrode layers in addition, and described two welding electrode layers are arranged at the surface of this second electrode lay and heat dissipating layer respectively.

10. overcurrent protective device as claimed in claim 9 is characterized in that: the material of this two welding electrodes layer is to be selected from tin or lead or ashbury metal or lead alloy.

11. overcurrent protective device as claimed in claim 7 is characterized in that: it comprises two welding electrode layers in addition, and described two welding electrode layers are arranged at the surface of this second electrode lay and heat dissipating layer respectively, and this conductive pole is connected to this two welding electrodes layer in addition.

12. the manufacture method of an overcurrent protective device is characterized in that: it comprises the following step:

The first step provides at least one positive temperature coefficient element, and it is made up of stacked being located between one first electrode layer and the second electrode lay of a PTC material;

In second step, form at least one binding glue-line on this at least one positive temperature coefficient element surface;

In the 3rd step, form at least one heat dissipating layer on this at least one binding glue-line surface;

The 4th step, form one first separator, this heat dissipating layer, binding glue-line and first electrode layer are divided into two parts separately, with blocking-up respectively this heat dissipating layer, link being electrically connected between two parts of the glue-line and first electrode layer, and formation one second separator, this the second electrode lay is divided into two parts, with being electrically connected between two parts of blocking this second electrode lay.

13. the manufacture method of overcurrent protective device as claimed in claim 12 is characterized in that: it comprises one in addition and makes at least one conductive pole to connect the step of this first and second electrode layer.

14. the manufacture method of overcurrent protective device as claimed in claim 12 is characterized in that: the step that it is included in described heat dissipating layer in addition and the second electrode lay surface makes the welding electrode layer respectively.

15. the manufacture method of overcurrent protective device as claimed in claim 13 is characterized in that: it comprises a step of making the welding electrode layer respectively on heat dissipating layer and the second electrode lay surface in addition, and this conductive pole is connected to this two welding electrodes layer in addition.

16. the manufacture method of overcurrent protective device as claimed in claim 13 is characterized in that: this conductive pole is to utilize plating or filling conductive paste to make.

17. the manufacture method of overcurrent protective device as claimed in claim 12 is characterized in that: this first or second separator is to utilize the mode of etching, laser, excision or milling to form opening, and this opening fill insulant is formed.

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