CN103106988A - Thermistor element - Google Patents

Abstract

The invention discloses a thermistor element, which comprises a thin plate type resistor element, a first insulating layer, a first electrode, a second electrode and a first heat conduction layer. The sheet-type resistance element comprises a first conductive member, a second conductive member and a polymer material layer stacked therebetween, wherein the polymer material layer has a positive temperature coefficient or a negative temperature coefficient. The first insulating layer is disposed on the first conductive member. The first electrode is electrically connected to the first conductive member. The second electrode is electrically connected to the second conductive member and electrically isolated from the first electrode. The first heat conduction layer is arranged on the surface of the first insulation layer, the heat conductivity of the first heat conduction layer is at least 30W/mK, and the thickness of the first heat conduction layer is 15-250 μm. The invention can greatly improve the heat transfer efficiency of the element, thereby improving the maintenance current of the product.

Description

Thermistor element

technical field

The present invention relates to surface mountable (SMD) variable thermistor elements made of conductive polymer materials, such as positive temperature coefficient (PTC) elements and negative temperature coefficient (NTC) elements, which can be applied to printed circuit boards (PCBs) ) on the current protection and detection of abnormal temperature environment.

Background technique

Since the resistance of conductive composite materials with positive temperature coefficient (Positive Temperature Coefficient; PTC) characteristics responds sensitively to temperature changes, it can be used as a material for current sensing components and has been widely used in overcurrent protection components or circuit components. superior. Because the resistance of the PTC conductive composite material can maintain an extremely low value at normal temperature, the circuit or battery can operate normally. However, when an over-current or over-temperature phenomenon occurs in a circuit or a battery, its resistance value will instantly increase to a high resistance state (at least 10 ² Ω), and the excessive current Reduced to achieve the purpose of protecting the battery or circuit components.

In the design and manufacture of high-density circuits, the requirements for the size of protective components must meet the requirements of lightness, thinness, and tinyness, and the design of surface-mounted components must be achieved in terms of installation. Therefore, PTC components made of organic polymer materials have been designed into different types of surface mount electronic components. However, due to the limitation of component size and poor heat transfer, the hold current of the product cannot be increased. In addition, because the thermal insulation of the element is too high, the sensitivity to the ambient temperature may also be too low.

Contents of the invention

In order to overcome the defects of the above design, the feature of the present invention is that a heat conduction layer is added on the surface of the thermistor element in order to conduct heat quickly. In this way, the holding current of the element is increased and the temperature sensitivity to the environment is increased.

According to an embodiment of the present invention, the thermistor element includes a thin-plate resistance element, a first insulating layer, a first electrode, a second electrode, and a first heat conducting layer. The thin-plate resistance element includes a first conductive member, a second conductive member and a polymer material layer, wherein the polymer material layer is stacked between the first conductive member and the second conductive member, and has a positive or negative temperature coefficient characteristic. The first insulating layer is disposed on the first conductive member, and the surface of the first insulating layer extends to form a first plane. The first electrode is electrically connected to the first conductive member. The second electrode is electrically connected to the second conductive member and is electrically isolated from the first electrode. The first heat conduction layer is arranged on the surface of the first insulation layer, its thermal conductivity is at least 30W/mK, and the thickness of the first heat conduction layer is 15-250 μm. In one embodiment, part of the first electrode and the second electrode are formed on the first plane, and form the first surface of the thermistor element with the first heat conduction layer, and the first electrode, the second electrode on the first surface and the sum of the areas of the first heat conducting layer is 40-90% of the area of the first surface.

In one embodiment, the thermistor element further includes a second insulating layer and a second heat conduction layer, the second insulating layer is disposed on the second conductive member, and the surface of the second insulating layer extends to form a second plane. The second heat conduction layer is arranged on the surface of the second insulating layer, wherein part of the first electrode and the second electrode are formed on the second plane, and form the second surface of the thermistor element with the second heat conduction layer, and the first The sum of the areas of the first electrode, the second electrode and the second heat conducting layer on the two surfaces is 40-90% of the area of the second surface.

In one embodiment, the aforementioned first conductive member and the first heat conduction layer, or the second conductive member and the second heat conduction layer may be connected by a heat conduction connector.

The present invention improves the appearance of traditional SMD products, increases the heat conduction area or heat conduction/conduction path of components, and can also be matched with solder pads with heat transfer effects, thereby greatly improving the heat transfer efficiency of components, thereby improving product maintenance. current. In addition, the present invention can also increase the sensitivity to ambient temperature to provide battery element protection and various electronic product applications.

Description of drawings

1A and FIG. 1B are schematic diagrams of a thermistor element according to a first embodiment of the present invention;

2A and 2B are schematic diagrams of a thermistor element according to a second embodiment of the present invention;

Fig. 3 is the schematic diagram of the thermistor element of the third embodiment of the present invention;

FIG. 4 is a schematic diagram of a thermistor element according to a fourth embodiment of the present invention.

Wherein, the reference signs are explained as follows:

10, 20, 30, 40 thermistor elements

11 resistance element

12 first conductive member

13 second conductive member

14 polymer material layers

15 first insulating layer

16 second insulating layer

17 first electrode

18 second electrode

19 first conductive connector

20 second conductive connector

21 first heat conduction layer

22 second heat conduction layer

24 first surface

25 solder mask

26 second surface

27 The first heat-conducting connector

28 The second heat-conducting connector

31 first plane

32 second plane

41 resistance element

42 first conductive member

43 second conductive member

44 polymer material layers

45 solder mask

46 conductive layer

47 first electrode

48 second electrode

49 conductive connectors

51 surfaces

53 heat conduction layer

57 thermal connectors

61 planes

Detailed ways

In order to make the above-mentioned and other technical content, features, and advantages of the present invention more obvious and understandable, the following specifically cites relevant embodiments, together with the accompanying drawings, and describes them in detail as follows:

FIG. 1A is a schematic diagram of a thermistor according to a first embodiment of the present invention. FIG. 1B is a top view of the thermistor element shown in FIG. 1 . The thermistor 10 includes a thin plate resistance element 11 , a first insulating layer 15 , a second insulating layer 16 , a first electrode 17 and a second electrode 18 . The thin-plate resistance element 11 comprises a first conductive member 12, a second conductive member 13 and a polymer material layer 14, wherein the polymer material layer 14 is stacked between the first conductive member 12 and the second conductive member 13, which contains Conductive particles, and have the characteristics of positive temperature or negative temperature coefficient. The polymer materials suitable for the present invention include: polyethylene, polypropylene, polyfluoroethylene, the aforementioned mixtures and copolymers, and the like. The conductive particles can be metal particles, carbon particles, metal oxides, metal carbides, or a mixture of the foregoing materials. The first insulating layer 15 is disposed on the first conductive member 12 , and the second insulating layer 16 is disposed on the second conductive member 13 . The insulating layers 15, 16 may comprise polypropylene, glass fibers or heat dissipating materials. The heat dissipation material includes polymer materials of thermosetting plastics and fibers, and polymer materials with interpenetrating structures of thermoplastic plastics and thermosetting plastics, which are disclosed in Taiwan Patent Publication No. 200816235, Publication No. I339088 and Publication No. 201101342, which is hereby incorporated herein. Wherein the polymer heat dissipation material has a thermal conductivity of at least 0.5W/mK, and 1W/mK, 2W/mK, 3W/mK, 4W/mK or 5W/mK or above are preferred embodiments of the present invention.

A part of the first electrode 17 is disposed on the first insulating layer 15 , that is, formed on the extended first plane 31 on the surface of the first insulating layer 15 . The first electrode 17 includes another part disposed on the second insulating layer 16 , that is, formed on the extended second plane 32 on the surface of the second insulating layer 16 . The first electrode 17 is electrically connected to the first conductive member 12 through a first conductive connector 19 . Similarly, the second electrode 18 includes a part disposed on the first insulating layer 15 or the first plane 31 , and includes another part disposed on the second insulating layer 16 or the second plane 32 . The second electrode 18 is electrically connected to the second conductive member 13 through the second conductive connector 20 and is electrically isolated from the first electrode 17 . In this embodiment, compared with the traditional electrode arrangement, the part of the first electrode 17 arranged on the surface of the first insulating layer 15 extends toward the direction of the second electrode 18 to serve as the first heat conducting layer 21 . Similarly, the part of the second electrode 18 disposed on the surface of the second insulating layer 16 extends toward the direction of the first electrode 17 to form the second heat conducting layer 22 . In other words, the first electrode 17 can be regarded as including the first heat conducting layer 21 , and the first heat conducting layer 21 is an extension of the first electrode 17 . The second electrode 18 can be considered to include a second thermally conductive layer 22 that is an extension of the second electrode 18 .

The first heat-conducting layer 21 and the second heat-conducting layer 28 can adopt materials such as metal nickel, copper, aluminum, lead, tin, silver, gold or their alloys with a thermal conductivity greater than 30W/mK, especially aluminum with a thermal conductivity greater than 200W/mK. Copper (about 238W/mK) and greater than 300W/mK (about 397W/mK), silver, gold, etc. have better heat conduction efficiency, and are better choices for the present invention.

In other words, the first conductive member 12 and the second conductive member 13 are respectively provided on the upper and lower surfaces of the resistance element 11 , and each extends to two opposite ends of the thin-plate resistance element 11 . The conductive members 12, 13 can be made of a flat metal thin film, through general etching methods (such as laser trimming (Laser Trimming), chemical etching or mechanical methods) to produce upper and lower sides, one on the left and one on the right, asymmetrical gaps (stripped metal) gaps in the membrane). The material of the above-mentioned conductive member can be nickel, copper, zinc, silver, gold, and alloys or multi-layer materials composed of the aforementioned metals. In addition, the notch can be rectangular, semicircular, triangular or irregular in shape and pattern, but the area of the notch should not exceed 25% of the total area of one side.

After the above-mentioned gap is formed by stripping the metal film, various excellent adhesive films (that is, insulating layers 15, 16, such as epoxy resin and glass fiber cloth) can be used to bond the resistance element 11 to the outer layer. The upper and lower metal copper films are solidified and sealed by hot pressing. Afterwards, the upper and lower outer copper films can be etched to produce electrodes, as shown in Figures 17 and 18.

The electrodes 17 and 18 at the left and right ends can selectively connect the electrodes in the upper, lower, left and right regions vertically through the electroplating method of the conductive connectors 19 and 20 or the comprehensive cutting surface. Between the first heat conduction layer 21 and the first and second electrodes 17 and 18 , or between the second heat conduction layer 22 and the first and second electrodes 17 and 18 can be etched to form electrical isolation. Wherein the spacing is at least 15 μm, 20 μm or 30 μm.

In one embodiment, an insulating solder resist layer 25 is used as isolation between the first electrode 17 and the second heat conduction layer 22 , and between the second electrode 18 and the first heat conduction layer 21 . Although the solder resist layer 25 used as the isolation in this embodiment is rectangular, other shapes of isolation such as semicircle, arc, triangle or irregular shapes and patterns are also applicable to the present invention.

The conductive connectors 19 and 20 in this embodiment are described by taking a semicircular via hole as an example. A layer of conductive metal (such as copper or gold) can be plated on the hole wall of the via hole by electroless plating or electroplating to achieve the purpose of connecting the upper and lower electrodes. In addition to a semicircle, the cross-sectional shape of the via hole can be a circle, a quarter circle, an arc, a square, a rhombus, a rectangle, a triangle, or a polygon.

The first electrode 17, the second electrode 18, and the first heat conduction layer 21 formed on the first insulating layer 15 (that is, the first plane 31) form the first surface 24 of the thermistor element 10; The first electrode 17 , the second electrode 18 and the second heat conducting layer 22 on the layer 16 (ie the second plane 32 ) form the second surface 26 of the thermistor element 10 .

In the first surface 24, the sum of the area of the first electrode 17, the second electrode 18 and the first heat conduction layer 21 accounts for about 40-90% of the area of the first surface 24, especially 45-85%, preferably 50-80%. In practical application, the aforementioned percentages may be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%. Similarly, the sum of the areas of the first electrode 17, the second electrode 18 and the second heat conducting layer 22 in the second surface 26 may be about 40-90%, especially 45-85% of the area of the second surface 26 as a whole. , preferably 50-80%. In practical application, the ratio can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%.

FIG. 2A is a schematic diagram of a thermistor element according to a second embodiment of the present invention. FIG. 2B is a top view of the thermistor element shown in FIG. 2A . Similar to the thermistor element 10 shown in FIGS. 1A and 1B , the thermistor element 20 also includes a thin-plate resistance element 11 , insulating layers 15 and 16 , a first electrode 17 , a second electrode 18 and the like. The difference from that shown in FIGS. 1A and 1B is that the first heat conducting layer 21 is not an extension of the first electrode 17 , but is separately provided on the first insulating layer 15 . The second heat conducting layer 22 is not an extension of the second electrode 18 , but is independently disposed on the second insulating layer 16 . In one embodiment, the first heat conduction layer 21 is separated from the first and second electrodes 17 and 18 by etching or isolating by a solder resist layer 25 . The second heat conduction layer 22 and the first and second electrodes 17 and 18 may also be etched to form a space or separated by a solder resist layer 25 . The ratio of the sum of the area of the first electrode 17, the second electrode 18 and the first heat conducting layer 21 to the area of the whole first surface 24 and the sum of the area of the first electrode 17, the second electrode 18 and the second heat conducting layer 22 to the whole second The ratio of the area of the surface 26 can also refer to the description of the first embodiment.

FIG. 3 is a schematic diagram of a thermistor element according to a third embodiment of the present invention. Compared with the thermistor element 20 shown in FIG. 2A , the thermistor element 30 is additionally provided with a heat conduction connecting piece 27 between the first heat conduction layer 21 and the first conductive member 12 to increase the heat conduction efficiency of the resistance element 11 . Likewise, a heat-conducting connector 28 can be disposed between the second heat-conducting layer 22 and the second conductive member 13 . The thermally conductive connectors 27, 28 can be made of the same metal nickel, copper, aluminum, lead, tin, silver, gold or their alloys as the thermally conductive layers 21, 22, etc., with a thermal conductivity greater than 30W/mK, especially with a thermal conductivity greater than 200W/mK. Aluminum of mK and copper, silver, gold or their alloys of more than 300 W/mK have the best heat conduction efficiency, and are preferred choices of the present invention.

The above design and manufacturing method can increase the number of resistive element layers to more than two layers (that is, include more than two resistive elements 11 ) for parallel connection to achieve a multi-layer parallel surface mount resistive element. In addition, the number of thermally conductive connectors 27 connecting the first thermally conductive layer 21 and the first conductive member 12 , or the thermally conductively connected members 28 connecting the second thermally conductive layer 22 and the second conductive member 13 may be multiple to increase thermal conductivity.

FIG. 4 is a schematic diagram of a thermistor element according to a fourth embodiment of the present invention. The thermistor 40 includes a thin-plate resistance element 41 , an insulating layer 55 , a first electrode 47 and a second electrode 48 . The thin-plate resistance element 41 includes a first conductive member 42, a second conductive member 43 and a polymer material layer 44, wherein the polymer material layer 44 is stacked between the first conductive member 42 and the second conductive member 43, which contains Conductive particles, and have the characteristics of positive temperature or negative temperature coefficient. The insulating layer 55 is disposed on the first conductive member 42 . The first electrode 47 is electrically connected to the first conductive member 42 through the conductive layer 46 . The first electrode 47 is formed on the extension plane 61 on the surface of the insulating layer 55 . The second electrode 48 is disposed on the insulating layer 55 (ie, the plane 61 ), is electrically connected to the second conductive member 43 through the conductive connector 49 , and is electrically isolated from the first electrode 47 . The heat conducting layer 53 is disposed on the surface of the insulating layer 55 . In one embodiment, the heat conduction layer 53 is preferably connected to the first conductive member 42 through a heat conduction connector 57 . Wherein the first electrode 47, the second electrode 48 and the heat conduction layer 53 formed on the plane 61 form the surface 51 of the thermistor element 40, and the sum of the areas of the first electrode 47, the second electrode 48 and the heat conduction layer 53 is the surface 40-90% of the area of 51, especially 45-85%, preferably 50-80%. In practical application, the ratio can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%.

Other structural types of other surface mount thermistor elements are also disclosed in Chinese Taiwan Patent Publication No. 415624 and Publication No. I282696. The relevant structural type disclosures of the above-mentioned patents are hereby incorporated herein. Thermistor elements with various structures above can apply the present invention to add a heat-conducting layer or further add a heat-conducting connector to increase the heat dissipation effect. In addition, the thickness of the aforementioned heat conducting layer is between 15-250 μm, and can also be 18 μm, 35 μm, 70 μm, 140 μm or 210 μm, wherein a thicker heat conducting layer has a better heat conducting effect.

Compared with the original SMD element structure, the present invention increases the size of the copper foil circuit as the heat conduction layer and/or increases the copper pillar structure as the heat conduction connector, so that the SMD element can conduct the excess heat source to the circuit, or the circuit substrate used. In the case of effectively suppressing the temperature rise, the holding current of the thermistor element can be greatly increased to meet the high current demand. At the same time, the circuit design can also improve the heat transfer and effectively increase the sensitivity of the element to the external temperature.

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 that do not depart from the present invention, and are covered by the scope of the following claims.

Claims (18)

1. a thermistor element, is characterized in that, comprising:

One sheet-type resistive element comprises the first conductive member, the second conductive member and polymer material layer, and wherein this polymer material layer is stacked between this first conductive member and this second conductive member, and has the characteristic of positive temperature or negative temperature coefficient;

One first insulating barrier is arranged on this first conductive member;

One first electrode is electrically connected this first conductive member;

One second electrode is electrically connected this second conductive member, and with this first electrode electrical isolation; And

One first heat-conducting layer is arranged at this first surface of insulating layer, and this first heat-conducting layer thermal conductivity is at least 30W/mK, and its thickness is between 15～250 μ m.

2. according to claim 1 thermistor element, wherein the extension of the surface of this first insulating barrier consists of the first plane, this second electrode of this first electrode of part and part is formed on this first plane, and and this first heat-conducting layer forms the first surface of this thermistor element, and in this first surface the area summation of this first electrode, this second electrode and this first heat-conducting layer be this first surface area 40～90%.

3. according to claim 1 thermistor element, it also comprises one second insulating barrier and one second heat-conducting layer, and this second insulating barrier is arranged on this second conductive member, and this second heat-conducting layer is arranged at this second surface of insulating layer.

4. according to claim 3 thermistor element, wherein the extension of the surface of this second insulating barrier consists of the second plane, this second electrode of this first electrode of part and part is formed on this second plane, and and this second heat-conducting layer forms the second surface of this thermistor element, and in this second surface the area summation of this first electrode, this second electrode and this second heat-conducting layer be this second surface area 40～90%.

5. according to claim 3 thermistor element, wherein this first electrode and this second electrode are formed at this first insulating barrier and this second surface of insulating layer.

6. according to claim 1 thermistor element, wherein this first heat-conducting layer extension that is this first electrode.

7. according to claim 2 thermistor element, wherein this first heat-conducting layer is arranged between this first electrode and this second electrode on this first plane.

8. according to claim 1 thermistor element, be wherein electrical isolation between this first heat-conducting layer and this first electrode and this second electrode.

9. according to claim 8 thermistor element, wherein between this first heat-conducting layer and this first electrode or this second electrode between every being at least 15 μ m.

10. according to claim 1 thermistor element, be wherein to isolate with welding resisting layer between this first heat-conducting layer and this first electrode and this second electrode.

11. thermistor element according to claim 1, wherein this first heat-conducting layer comprises nickel, copper, aluminium, lead, tin, silver, gold or its alloy.

12. thermistor element according to claim 1, it also comprises the heat-conducting connecting by this first insulating barrier, and this heat-conducting connecting connects this first heat-conducting layer and this first conductive member.

13. thermistor element according to claim 12, wherein the thermal conductivity of this heat-conducting connecting is at least 30W/mK.

14. thermistor element according to claim 12, wherein this heat-conducting connecting comprises nickel, copper, aluminium, lead, tin, silver, gold or its alloy.

15. thermistor element according to claim 1, wherein this first insulating barrier comprises polypropylene, glass fibre or heat sink material.

16. thermistor element according to claim 1, wherein the thermal conductivity of this first insulating barrier is at least 0.5W/mK.

17. thermistor element according to claim 1, it also comprises the first conducting connecting part and the second conducting connecting part, wherein this first conducting connecting part is used for this first electrode of electrical connection and this first conductive member, and this second conducting connecting part is used for connecting this second electrode and this second conductive member.

18. thermistor element according to claim 2, wherein in this first surface the area summation of this first electrode, this second electrode and this first heat-conducting layer be first surface area 50～80%.

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