TWI811678B - PTC circuit protection device - Google Patents

Abstract

A PTC circuit protection device includes a PTC polymer layer, a first conductive layer electrically connected to the PTC polymer layer, a second conductive layer electrically connected to the PTC polymer layer, and a first conductive layer disposed on the first conductive layer and an insulating layer unit on the second conductive layer, a first electrode formed on the insulating layer unit and electrically connected to the first conductive layer, and a first electrode formed on the insulating layer unit and electrically connected to the second conductive layer. The second electrode of the conductive layer, wherein the first electrode forms a first groove. The PTC circuit protection device of the present invention has excellent bonding strength to PCB.

Description

PTC circuit protection device

The present invention relates to a positive temperature coefficient (PTC) circuit protection device, and in particular to a PTC circuit protection device formed with grooves.

A positive temperature coefficient (PTC) element has the PTC effect, allowing it to be used as a circuit protection device (such as a resettable fuse). The PTC element includes a PTC polymer unit, and a first electrode and a second electrode formed on two opposite surfaces of the PTC polymer unit. The PTC polymer unit includes a polymer substrate containing a crystalline region and an amorphous region, and a granular conductive filler. The particulate conductive filler is dispersed in the amorphous region of the polymer substrate and forms a continuous conductive path for electrically connecting the first electrode and the second electrode. The PTC effect refers to a phenomenon in which when the temperature of the polymer substrate in the crystalline region is raised to its melting point, the crystals in the crystalline region begin to melt, thereby creating a new amorphous region. When the new amorphous region increases to the extent that it merges into the original amorphous region, the conductive path of the granular conductive filler will become discontinuous and the resistance of the PTC polymer unit will increase sharply, causing the first There is no electrical conduction between the electrode and the second electrode.

Referring to Figure 1, an existing surface-mounted PTC circuit protection device 1 includes a PTC unit 14, a first insulating layer 15, a second insulating layer 16, a first electrode 17 and a second electrode 18 . The PTC unit 14 includes a first conductive member 12 , a second conductive member 13 and a polymer layer 11 stacked between the first conductive member 12 and the second conductive member 13 . The polymer layer 11 exhibits PTC characteristics and includes a polymer base material and a granular conductive filler dispersed in the polymer base material. 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 first electrode 17 is electrically connected to the first conductive member 12 and is disposed on the first insulating layer 15 and further extends toward the second insulating layer 16 . Similarly, the second electrode 18 is electrically connected to the second conductive member 13 and is disposed on the second insulating layer 16 and further extends toward the first insulating layer 15 .

The above-mentioned existing surface-mounted PTC circuit protection device 1 is usually installed on an electronic device (such as a printed circuit board (not shown)) through solder. However, the solderability between the surface-mounted PTC circuit protection device 1 and the electronic equipment is not ideal.

Therefore, the object of the present invention is to provide a PTC circuit protection device that can overcome at least one of the above-mentioned shortcomings of the prior art.

Therefore, the PTC circuit protection device of the present invention includes a PTC polymer layer, a first conductive layer, a second conductive layer, an insulating layer unit, a first electrode and a second electrode. The first conductive layer is electrically connected to the PTC polymer layer. The second conductive layer is electrically connected to the PTC polymer layer and is spaced apart from the first conductive layer. The insulating layer unit is disposed on the first conductive layer and the second conductive layer. The first electrode is formed on the insulating layer unit, electrically connected to the first conductive layer and spaced apart from the second conductive layer. The second electrode is formed on the insulating layer unit, is electrically connected to the second conductive layer, and is spaced apart from the first conductive layer and the first electrode. Wherein, the first electrode is formed with a first groove, and the first groove is recessed from a surface of the first electrode toward the PTC polymer layer.

The effect of the present invention is that the PTC circuit protection device has excellent bonding strength to PCB.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are designated with the same numbering.

In addition, the directional terms (such as: up, down) used in the specification and patent application scope of the present invention are simply intended to help describe the relative positions between the components of the present invention, and are not intended to limit each component in the actual implementation of the present invention. actual location.

Referring to FIG. 2 , the first embodiment of the PTC circuit protection device 2 of the present invention includes a PTC unit 21 , an insulating layer unit 23 , a first electrode 24 and a second electrode 25 . The PTC unit 21 includes a PTC polymer layer 210, a first conductive layer 211 and a second conductive layer 212. The first conductive layer 211 is electrically connected to the PTC polymer layer 210 . The second conductive layer 212 is electrically connected to the PTC polymer layer 210 and is spaced apart from the first conductive layer 211 . The insulating layer unit 23 is disposed on the first conductive layer 211 and the second conductive layer 212 . The first electrode 24 is formed on the insulating layer unit 23 , is electrically connected to the first conductive layer 211 and is spaced apart from the second conductive layer 212 . The second electrode 25 is formed on the insulating layer unit 23 , is electrically connected to the second conductive layer 212 , and is spaced apart from the first conductive layer 211 and the first electrode 24 . The first electrode 24 is formed with a first groove 244 , and the first groove 244 is recessed from a surface of the first electrode 24 toward the PTC polymer layer 210 . In some embodiments of the present invention, the second electrode 25 is formed with a second groove 254 , and the second groove 254 is recessed from a surface of the second electrode 25 toward the PTC polymer layer 210 .

The first electrode 24 has a first groove defining wall 245 that defines the first groove 244 , and the second electrode 25 has a second groove defining wall 255 that defines the second groove 254 . In some embodiments of the present invention, the surface area of the first groove defining wall 245 is not less than 10% of the surface area of the first electrode 24 . In some embodiments of the present invention, the surface area of the second groove defining wall 255 is not less than 10% of the surface area of the second electrode 25 . It should be noted that the above-mentioned surface area of the first electrode 24 and the second electrode 25 respectively means that the first electrode 24 and the second electrode 25 are not in contact with the PTC unit 21 and the insulating layer unit 23 and do not include respectively. The surface area of the portion extending to be electrically connected to the first conductive layer 211 and the second conductive layer 212 .

In some embodiments of the present invention, the surface areas of the first groove defining wall 245 and the second groove defining wall 255 are 10% to 80% of the surface areas of the first electrode 24 and the second electrode 25 respectively. .

In some embodiments of the present invention, the surface areas of the first groove defining wall 245 and the second groove defining wall 255 are 25% to 75% of the surface areas of the first electrode 24 and the second electrode 25 respectively. .

In some embodiments of the present invention, the PTC polymer layer 210 includes an upper surface, a lower surface opposite to the upper surface, and a surrounding surface interconnected between the upper surface and the lower surface. In this embodiment, the first conductive layer 211 is disposed on the upper surface, and the second conductive layer 212 is disposed on the lower surface. The insulating layer unit 23 includes a first insulating layer 231 disposed on the first conductive layer 211 and a second insulating layer 232 disposed on the second conductive layer 212 . The first electrode 24 includes an upper first electrode portion 241 disposed on the first insulating layer 231, a lower first electrode portion 242 disposed on the second insulating layer 232, and a first electrode formed on the PTC polymer. First electrode connection 243 on the surrounding surface of layer 210 . The first electrode connecting portion 243 is interconnected between the upper first electrode portion 241 and the lower first electrode portion 242 . The second electrode 25 includes an upper second electrode portion 251 disposed on the first insulating layer 231, a lower second electrode portion 252 disposed on the second insulating layer 232, and a second electrode formed on the PTC polymer. Second electrode connection 253 on the surrounding surface of layer 210 . The second electrode connecting portion 253 is interconnected between the upper second electrode portion 251 and the lower second electrode portion 252 .

In some embodiments of the present invention, the first groove 244 of the first electrode 24 is formed on one of the upper first electrode part 241 and the lower first electrode part 242 . In some embodiments of the present invention, the first electrode 24 has two first grooves 244, and the first grooves 244 are respectively formed on the upper first electrode part 241 and the lower first electrode part 242. .

In some embodiments of the present invention, the second groove 254 of the second electrode 25 is formed on one of the upper second electrode part 251 and the lower second electrode part 252 . In some embodiments of the present invention, the second electrode 25 has two second grooves 254, and the second grooves 254 are respectively formed on the upper second electrode part 251 and the lower second electrode part 252. .

Referring to Figures 3 and 4, the second embodiment of the PTC circuit protection device 2 of the present invention is similar to the first embodiment, and the differences are as follows.

Referring to FIGS. 3 and 4 , the PTC polymer layer 210 includes an upper surface, a lower surface opposite to the upper surface, and a surrounding surface interconnected between the upper surface and the lower surface. In this embodiment, the first conductive layer 211 includes an upper first conductive portion 2111 disposed on the upper surface and a lower first conductive portion 2112 disposed on the lower surface. The second conductive layer 212 includes an upper second conductive portion 2121 disposed on the upper surface and a lower second conductive portion 2122 disposed on the lower surface. The insulating layer unit 23 includes a first insulating layer 231 disposed on the first conductive layer 211 and a second insulating layer 232 disposed on the second conductive layer 212 . The first insulating layer 231 includes an upper first insulating portion 2311 disposed on the upper first conductive portion 2111 and a lower first insulating portion 2312 disposed on the lower first conductive portion 2112 . The second insulating layer 232 includes an upper second insulating portion 2321 disposed on the upper second conductive portion 2121 and a lower second insulating portion 2322 disposed on the lower second conductive portion 2122 . The first electrode 24 includes an upper first electrode portion 241 disposed on the upper first insulating portion 2311, a lower first electrode portion 242 disposed on the lower first insulating portion 2312, and a first electrode portion 242 formed on the PTC. The first electrode connection portion 243 on the surrounding surface of the polymer layer 210 . The first electrode connecting portion 243 is interconnected between the upper first electrode portion 241 and the lower first electrode portion 242 . The second electrode 25 includes an upper second electrode portion 251 disposed on the upper second insulating portion 2321, a lower second electrode portion 252 disposed on the lower second insulating portion 2322, and a second electrode formed on the PTC. The second electrode connection portion 253 on the surrounding surface of the polymer layer 210 . The second electrode connecting portion 253 is interconnected between the upper second electrode portion 251 and the lower second electrode portion 252 .

In some embodiments of the present invention, the first groove 244 of the first electrode 24 is formed on one of the upper first electrode part 241 and the lower first electrode part 242 . In some embodiments of the present invention, the first electrode 24 is formed with two first grooves 244, and the first grooves 244 are respectively formed on the upper first electrode part 241 and the lower first electrode part 242. superior.

In some embodiments of the present invention, the second groove 254 of the second electrode 25 is formed on one of the upper second electrode part 251 and the lower second electrode part 252 . In some embodiments of the present invention, the first electrode 24 is formed with two second grooves 254, and the second grooves 254 are respectively formed on the upper second electrode part 251 and the lower second electrode part 252. superior.

In some embodiments of the present invention, the upper first electrode part 241 has a first groove defining wall 245 that defines the first groove 244, and the upper second electrode part 251 has a first groove defining wall 245 that defines the second groove. The surface area of the second groove definition wall 255 of the groove 254, the first groove definition wall 245 and the second groove definition wall 255 is not less than the upper surface area of the upper first electrode part 241 and the upper second electrode part 251. 10% of the surface area.

In some embodiments of the present invention, the surface area of the first groove defining wall 245 and the second groove defining wall 255 is 10% of the upper surface area of the upper first electrode part 241 and the upper second electrode part 251 % to 80%, or 25% to 75%.

In some embodiments of the present invention, the surface area of the first groove defining wall 245 is not less than 10% of the upper surface area of the upper first electrode part 241, or 10% of the upper surface area of the upper first electrode part 241. % to 80%, or 25% to 75%. In some embodiments of the present invention, the surface area of the second groove defining wall 255 is not less than 10% of the upper surface area of the upper second electrode part 251 , or 10% of the upper surface area of the upper second electrode part 251 % to 80%, or 25% to 75%. In some embodiments of the present invention, an insulating spacer 28 is disposed between the upper first conductive part 2111 and the upper second conductive part 2121. The insulating spacer 28 may also be disposed between the lower first conductive part 2112 and the lower second conductive part 2122 .

In some embodiments of the present invention, the PTC circuit protection device 2 further includes a third conductive layer 26 and a fourth conductive layer 27 . The third conductive layer 26 includes an upper third conductive portion 261 disposed between the upper first insulating portion 2311 and the upper first electrode portion 241 and a third conductive portion 261 disposed between the lower first insulating portion 2312 and the lower first electrode portion 241 . The lower third conductive portion 262 is between the electrode portions 242 . The fourth conductive layer 27 includes an upper fourth conductive portion 271 disposed between the upper second insulating portion 2321 and the upper second electrode portion 251 and a lower second insulating portion 2322 and the lower second electrode portion 251 . The lower fourth conductive portion 272 is between the electrode portions 252 .

In some embodiments of the present invention, each first conductive layer 211 and each second conductive layer 212 can be made of a metal material, such as metal foil, metal-plated foil (such as nickel-plated copper foil) wait.

In some embodiments of the present invention, the insulating layer unit 23 is made of epoxy resin.

In the present invention, the PTC polymer layer 210 includes a polymer base material and a granular conductive filler dispersed in the polymer base material. The polymer substrate can be made from a polymer composition containing a non-grafted olefin polymer (eg, high density polyethylene (HDPE)). In some embodiments of the present invention, the polymer composition further includes a grafted olefin polymer. In some embodiments of the present invention, the grafted olefinic polymer includes an olefinic polymer grafted with carboxylic acid anhydride. The carboxylic acid anhydride-grafted olefin polymer may be a carboxylic acid anhydride-grafted high-density polyethylene. In this embodiment, the olefin polymer grafted with carboxylic anhydride is HDPE grafted with maleic anhydride.

In the present invention, the granular conductive filler can be made of carbon black, metal, conductive ceramic materials or combinations thereof. In some embodiments of the present invention, the granular conductive filler is selected from carbon black powder, metal powder, conductive ceramic powder or combinations thereof.

Examples of the particulate conductive filler include titanium carbide, zirconium carbide, vanadium carbide, niobium carbide, tantalum carbide, chromium carbide, molybdenum carbide, tungsten carbide, titanium nitride, zirconium nitride, vanadium nitride, niobium nitride, nitride Tantalum, chromium nitride, titanium disilicide, zirconium disilicide, niobium disilicide, tungsten disilicide, gold, silver, copper, aluminum, nickel, nickel metallized glass beads, nickel metallized graphite, Ti-Ta solid solution, W-Ti-Ta-Cr solid solution, W-Ta solid solution, W-Ti-Ta-Nb solid solution, W-Ti-Ta solid solution, W-Ti solid solution, Ta-Nb solid solution entity or combination thereof.

In some embodiments of the present invention, the polymer substrate may account for 5 wt% to 50 wt% of the PTC polymer layer 210, and the particulate conductive filler may account for 50 wt% of the PTC polymer layer 210. to 95 wt%.

The method of manufacturing the PTC circuit protection device 2 includes the following steps: (a) providing a PTC polymer layer 210; (b) electrically forming a first conductive layer 211 on the PTC polymer layer 210; (c) A second conductive layer 212 is electrically connected to the PTC polymer layer 210 and is spaced apart from the first conductive layer 211; (d) forming an insulating layer on the first conductive layer 211 and the second conductive layer 212 Unit 23; (e) heat press the PTC polymer layer 210, the first conductive layer 211, the second conductive layer 212 and the insulating layer unit 23 to form a stack; (f) form a stack on the stack The first electrode 24 electrically connected to the first conductive layer 211; (g) forming a second electrode 25 electrically connected to the second conductive layer 212 and spaced apart from the first electrode 24 on the stack; (h) ) A first groove 244 is formed on the first electrode 24, and the first groove 244 is recessed from a surface of the first electrode 24 toward the PTC polymer layer 210. In some specific embodiments of the present invention, the method further includes the step (i) forming a second groove 254 on the second electrode 25, the second groove 254 facing from a surface of the second electrode 25 toward The PTC polymer layer 210 is recessed.

The present invention will be further described with reference to the following examples, but it should be understood that these examples are only for illustration and should not be construed as limitations on the implementation of the present invention.

Example

<Example 1 (E1) ＞

First, 10.5 g HDPE (purchased from Taiwan Plastics Industry Co., Ltd., product model: HDPE9002) was used as a non-grafted olefin polymer, and 10.5 g of HDPE grafted with maleic anhydride (purchased from DuPont, product model: MB100D ) as an olefin polymer grafted with carboxylic anhydride, and 29 g of carbon black powder (purchased from Columbian Chemicals Company, product model: Raven 430UB) as a granular conductive filler.

Mix the above ingredients in a mixer (brand: Brabender), mix the ingredients at a temperature of 200°C and a stirring speed of 50 rpm for 10 minutes to obtain an ingredient mixture.

The above-mentioned ingredient mixture was placed in a mold and hot-pressed for 4 minutes at a hot-pressing temperature of 200°C and a hot-pressing pressure of 80 kg/cm ² to form multiple PTC polymer embryos. The embryos were taken out of the mold, sandwiched between two upper and lower pieces of nickel-plated copper foil, and hot-pressed at 200°C and 80 kg/ ^cm for 4 min, and then irradiated with Co-60 γ-rays using total radiation. Irradiate with a dose of 15 Mrad, and then etch the upper and lower nickel-plated copper foils respectively to form an upper first conductive part and an upper second conductive part that are spaced apart from each other, and a lower first conductive part and a lower second conductive part that are spaced apart from each other to obtain a PTC unit with a thickness of 0.32 mm. As shown in FIGS. 3 and 4 , the upper first conductive part and the lower first conductive part jointly serve as the first conductive layer, and the upper second conductive part and the lower second conductive part jointly serve as the second conductive layer. .

Next, an epoxy resin layer is provided on the two exposed opposite surfaces of the first conductive layer, the second conductive layer and the PTC polymer layer, and then hot pressed to form the first insulating layer, the second insulating layer and the PTC polymer layer. An insulating spacer is provided between the first conductive layer and the second conductive layer (as shown in Figures 3 and 4).

A third conductive layer and a fourth conductive layer are respectively disposed on the first insulating layer and the second insulating layer to obtain a laminate. The formation method of the third conductive layer and the fourth conductive layer is similar to the formation method of the above-mentioned first conductive layer and the second conductive layer. A first electrode and a second electrode are respectively plated on the third conductive layer and the fourth conductive layer, and are plated on the side surface of the laminate to extend and connect the third conductive layer and the fourth conductive layer respectively. Upper and lower parts. The first electrode includes an upper first electrode part, a lower first electrode part and a first electrode connecting part. The second electrode includes an upper second electrode part, a lower second electrode part and a second electrode connecting part. A CNC engraving machine (purchased from Shanghai Yidiao Company, model: YD3040G) was used to form a first groove and a second groove respectively on the upper first electrode part and the upper second electrode part. The first groove and the second groove are respectively defined by a first groove defining wall and a second groove defining wall. In Embodiment 1, the surface area of the first groove defining wall is 10% of the upper surface area of the upper first electrode part, and the surface area of the second groove defining wall is 10% of the upper surface area of the upper second electrode part. %. Finally, we got E1’s PTC circuit protection device.

<Example 2 to 7 (E2-E7) ＞

The process conditions of the PTC circuit protection devices of E2-E7 are similar to those of E1. The difference is that the surface areas of the first groove defining wall and the second groove defining wall are based on the upper first electrode part and the upper second electrode part. The proportion of the upper surface area (as shown in Table 1).

<Comparative Example 1 (CE1) ＞

The manufacturing conditions of the PTC circuit protection device of CE1 are similar to those of E1, except that no grooves are formed on the first electrode and the second electrode (as shown in Table 1). 【Table 1】 The surface area of the first groove defining wall and the second groove defining wall is based on the proportion of the upper surface area of the upper first electrode part and the upper second electrode part. E1 10% E2 25% E3 50% E4 75% E5 80% E6 5% E7 90% CE1 0%

Performance testing

[ Solderability test ]

Coat the upper surfaces of the upper first electrode part and the upper second electrode part of the PTC circuit protection devices of E1-E7 and CE1 with tin-based solder respectively. Subsequently, the PTC circuit protection devices of E1-E7 and CE1 were respectively attached to a printed circuit board (PCB) through the tin-based solder to obtain test samples of E1-E7 and CE1 respectively. Next, each test sample was placed in a reflow oven for reflow soldering. The peak temperature of the reflow furnace is set to 285°C to control the reflow interval to be above the liquidus temperature of 260°C for 20 seconds, and the overall reflow time is 4 minutes. Then, test the solderability of each test sample (taking "the area covered by solder accounting for more than 90% of the upper surface area of the upper first electrode part and the upper second electrode part" as the standard for successful welding), and calculate the soldering The ratio of successful test samples, the results are shown in Table 2. 【Table 2】 Total number of test samples (pieces) Number of successfully welded test samples (pieces) Welding success rate E1 1000 995 99.5% E2 1000 1000 100.0% E3 1000 1000 100.0% E4 1000 1000 100.0% E5 1000 983 98.3% E6 1000 945 94.5% E7 1000 948 94.8% CE1 1000 913 91.3%

The results in Table 2 show that compared to the PTC circuit protection device of CE1 (without grooves), the PTC circuit protection devices of E1-E7 (especially the grooves of E1-E5) account for 10% to 80% of the surface area of the defined wall. %) has good solderability for PCB. In particular, when the surface area of the test sample's groove-defined wall of the PTC circuit protection device accounted for 25% to 75% (E2-E4), the welding success rate was as high as 100%.

In summary, the PTC circuit protection device 2 of the present invention forms the groove on its electrode and even further controls the proportion of the surface area of the groove defining wall. The PTC circuit protection device 2 has excellent bonding strength to the PCB. , so the purpose of the present invention can indeed be achieved.

However, the above are only examples of the present invention, and should not be used to limit the scope of the present invention. All simple equivalent changes and modifications made based on the patent scope of the present invention and the content of the patent specification are still within the scope of the present invention. Within the scope covered by the patent of this invention.

1:PTC circuit protection device 11:Polymer layer 12: First conductive member 13: Second conductive member 14:PTC unit 15: First insulation layer 16: Second insulation layer 17: First electrode 18:Second electrode 2:PTC circuit protection device 21:PTC unit 210:PTC polymer layer 211: First conductive layer 2111: Go to the first conductive department 2112: Lower first conductive part 2121: Upper second conductive part 2122: Lower second conductive part 212: Second conductive layer 23:Insulation layer unit 231: First insulation layer 2311: Go to the first insulation department 2312: Lower first insulation department 232: Second insulation layer 2321: Upper second insulation part 2322:Lower second insulation part 24: First electrode 241: Upper first electrode part 242: Lower first electrode part 243: First electrode connection part 244: first groove 245: The first groove defines the wall 25:Second electrode 251: Upper second electrode part 252: Lower second electrode part 253: Second electrode connection part 254: Second groove 255: The second groove defines the wall 26:Third conductive layer 261: Go to the third conductive part 262: Lower third conductive part 27:Fourth conductive layer 271: Upper fourth conductive part 272: Lower fourth conductive part 28: Insulation gap

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: [Figure 1] is a schematic cross-sectional view of an existing PTC circuit protection device; [Figure 2] is a schematic cross-sectional view of the first embodiment of the PTC circuit protection device of the present invention; [Figure 3] is a schematic cross-sectional view of the second embodiment of the PTC circuit protection device of the present invention; and [Fig. 4] is a schematic perspective view of the second embodiment.

2:PTC circuit protection device

21:PTC unit

210:PTC polymer layer

211: First conductive layer

2111: Go to the first conductive department

2112: Lower first conductive part

2121: Upper second conductive part

2122: Lower second conductive part

212: Second conductive layer

23:Insulation layer unit

231: First insulation layer

2311: Go to the first insulation department

2312: Lower first insulation department

232: Second insulation layer

2321: Upper second insulation part

2322:Lower second insulation part

24: First electrode

241: Upper first electrode part

242: Lower first electrode part

243: First electrode connection part

244: first groove

245: The first groove defines the wall

25:Second electrode

251: Upper second electrode part

252: Lower second electrode part

253: Second electrode connection part

254: Second groove

255: The second groove defines the wall

26:Third conductive layer

261: Go to the third conductive part

262: Lower third conductive part

27:Fourth conductive layer

271: Upper fourth conductive part

272: Lower fourth conductive part

28: Insulation gap

Claims (17)

A PTC circuit protection device, including: a PTC polymer layer having an upper surface, a lower surface opposite to the upper surface, and a surrounding surface interconnected between the upper surface and the lower surface; a first conductive layer , electrically connected to the PTC polymer layer, and includes an upper first conductive part disposed on the upper surface and a lower first conductive part disposed on the lower surface; a second conductive layer, electrically is disposed connectedly on the PTC polymer layer and spaced apart from the first conductive layer, and includes an upper second conductive portion disposed on the upper surface and a lower second conductive portion disposed on the lower surface; An insulating layer unit includes a first insulating layer disposed on the first conductive layer and a second insulating layer disposed on the second conductive layer. The first insulating layer includes a first conductive layer disposed on the upper conductive layer. The upper first insulating part is provided on the upper first insulating part and a lower first insulating part is provided on the lower first conductive part. The second insulating layer includes an upper second insulating part provided on the upper second conductive part and a lower first insulating part. a lower second insulating part provided on the lower second conductive part; a first electrode formed on the insulating layer unit, electrically connected to the first conductive layer and spaced apart from the second conductive layer, and includes a an upper first electrode portion disposed on the upper first insulating portion, a lower first electrode portion disposed on the lower first insulating portion, and a first electrode formed on the surrounding surface of the PTC polymer layer a connecting portion, the first electrode connecting portion is interconnected between the upper first electrode portion and the lower first electrode portion; and a second electrode is formed on the insulating layer unit, electrically connected to the second conductive layer and with The first conductive layer and the first electrode are spaced apart and include It includes an upper second electrode portion disposed on the upper second insulating portion, a lower second electrode portion disposed on the lower second insulating portion, and a third electrode formed on the surrounding surface of the PTC polymer layer. Two electrode connection parts, the second electrode connection part is interconnected between the upper second electrode part and the lower second electrode part, wherein the first electrode forms a first groove, and the first groove is formed from the first One surface of the electrode is recessed toward the PTC polymer layer. The PTC circuit protection device of claim 1, wherein the second electrode is formed with a second groove, and the second groove is recessed from a surface of the second electrode toward the PTC polymer layer. The PTC circuit protection device of claim 2, wherein the first electrode has a first groove defining wall that defines the first groove, and the second electrode has a third groove that defines the second groove. Two grooves define walls, and the surface areas of the first groove definition wall and the second groove definition wall are not less than 10% of the surface areas of the first electrode and the second electrode. The PTC circuit protection device of claim 2, wherein the second groove of the second electrode is formed on one of the upper second electrode part and the lower second electrode part. The PTC circuit protection device of claim 1, wherein the first groove of the first electrode is formed on one of the upper first electrode part and the lower first electrode part. The PTC circuit protection device according to claim 1, wherein the first electrode is formed with two first grooves, and the first grooves are respectively formed on the upper first electrode part and the lower first electrode part. . The PTC circuit protection device of claim 6, wherein the second electrode is formed with at least one second groove, and the at least one second groove is formed in the upper second electrode part and the lower second electrode part. Enter one of them. The PTC circuit protection device according to claim 7, wherein the upper first electrode part has a first groove defining wall that defines the first groove, and the upper second electrode part has a first groove defining wall that defines the second groove. The surface area of the second groove definition wall of the groove is not less than 10% of the upper surface area of the upper first electrode part and the upper second electrode part. The PTC circuit protection device according to claim 8, wherein the surface area of the first groove defining wall and the second groove defining wall is 10% of the upper surface area of the upper first electrode part and the upper second electrode part. % to 80%. The PTC circuit protection device according to claim 9, wherein the surface area of the first groove defining wall and the second groove defining wall is 25% of the upper surface area of the upper first electrode part and the upper second electrode part. % to 75%. The PTC circuit protection device of claim 1 further includes an insulating spacer, the insulating spacer is disposed between the upper first conductive part and the upper second conductive part. The PTC circuit protection device according to claim 1, further comprising a third conductive layer and a fourth conductive layer, wherein the third conductive layer includes a first insulating part and an upper first electrode part. an upper third conductive part therebetween and a lower third conductive part disposed between the lower first insulating part and the lower first electrode part; and The fourth conductive layer includes an upper fourth conductive portion disposed between the upper second insulating portion and the upper second electrode portion and a second conductive portion disposed between the lower second insulating portion and the lower second electrode portion. Lower fourth conductive part. The PTC circuit protection device of claim 1, wherein each first conductive layer and each second conductive layer are nickel-plated copper foils. The PTC circuit protection device according to claim 1, wherein the insulating layer unit is made of epoxy resin. The PTC circuit protection device according to claim 1, wherein the PTC polymer layer includes a polymer base material and a granular conductive filler dispersed in the polymer base material, and the polymer base material includes a non-contact branched olefin polymer. The PTC circuit protection device according to claim 15, wherein the polymer substrate further includes an olefin polymer grafted with carboxylic anhydride. The PTC circuit protection device of claim 15, wherein the granular conductive filler is selected from carbon black powder, metal powder, conductive ceramic powder or combinations thereof.

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