TW201712698A - Over-current protection device - Google Patents

Abstract

An over-current protection device includes first and second electrodes and a multilayered structure including first and second PTC polymer material layers. The first PTC polymer material layer includes a first polymer matrix and a particulate conductive filler. The second PTC polymer material layer includes a second polymer matrix and a particulate conductive filler. The second polymer matrix is made from a second polymer composition. One of the first and second polymer compositions contains polyvinylidene fluoride and polyolefin and the other of the first and second polymer compositions contains polyolefin or polyvinylidene fluoride.

Description

Overcurrent protection device

The present invention relates to an overcurrent protection device, and more particularly to an overcurrent protection device comprising a layer of two PTC polymer materials, wherein a layer of PTC polymer material comprises a layer containing polyvinylidene fluoride (PVDF). And a polymer substrate obtained by polymerizing a polyolefin.

Positive temperature coefficient (PTC) materials are suitable as protective devices [eg fuses] due to their positive temperature coefficient effect.

Referring to FIG. 1, a conventional overcurrent protection device includes a PTC polymer material layer 81, and first electrodes 82 and second electrodes 83 respectively formed on opposite sides of the PTC polymer material layer 81. The PTC polymer material layer 81 comprises a polymeric substrate of a polymeric material and a conductive particulate filler (not shown). The polymer material contains a crystalline region (not shown) and an amorphous region (not shown). The conductive particulate filler is dispersed in the amorphous region of the polymer substrate, and a continuous conductive path for electrical conduction is formed between the first electrode 82 and the second electrode 83. The phenomenon of the positive temperature coefficient effect is that when the temperature of the polymer substrate rises to its melting point, the crystal in the crystal region starts. Melting, which in turn produces a new amorphous zone. When the new amorphous region is increased to a range that can be combined with the original amorphous region, the conductive path of the conductive particulate filler becomes discontinuous and the electrical resistance of the PTC polymer material is greatly increased, thereby resulting in the first electrode. 82 is disconnected from the second electrode 83.

The overcurrent protection device can adjust the operating temperature by adjusting the composition of the polymer substrate. However, when the polymeric substrate is made of a polyolefin, the operating temperature can only range from about -40 ° C to about 85 ° C.

To achieve a higher and wider operating temperature range (eg, between -40 ° C and 125 ° C), the polymeric substrate can be made from polyvinylidene fluoride (PVDF).

U.S. Patent No. 5,451,919 discloses a conductive polymeric composition having a resistivity of less than 10 ohm-cm at 20 °C. The conductive polymer composition contains at least 50 vol% of polyvinylidene fluoride and 1 to 20 vol% of the second crystalline fluorinated polymer. The conductive polymer composition is compression-molded to form a plaque. Both sides of the plate are electrodeposited by nickel foil to form a laminate. The laminate was irradiated with an electron beam through a radiation amount of 10 Mrads. The polyvinylidene fluoride is marketed under the trade name Kynar. However, the operating voltage or the breakdown voltage of the overcurrent protection device including the foregoing conductive polymer can only reach 30 Vdc according to the thermal runaway test.

In summary, it is still necessary to simultaneously increase the operating temperature and operating voltage of the overcurrent protection device.

Accordingly, a first object of the present invention is to provide an overcurrent protection device having a high operating temperature and a high operating voltage.

Therefore, the overcurrent protection device of the present invention comprises a first electrode, a second electrode and a multilayer structure. The multilayer structure is located between the first electrode and the second electrode, and includes a first PTC polymer material layer and a second PTC polymer material layer, wherein a PTC polymer material layer is stacked on another PTC polymer material layer And glued to each other. The first PTC polymer material layer includes a first polymer substrate and a particulate conductive filler dispersed in the first polymer substrate. The first polymeric substrate is made from a first polymeric composition. The second PTC polymer material layer includes a second polymer substrate and a particulate conductive filler dispersed in the second polymer substrate. The second polymeric substrate is made from a second polymeric composition. One of the first polymer composition and the second polymer composition contains polyvinylidene fluoride and polyolefin, and the other contains polyolefin or polyvinylidene fluoride. When the first polymerization composition and the second polymerization composition contain polyolefin or one of polyvinylidene fluoride containing polyolefin, it does not substantially contain polyvinylidene fluoride; when the first polymerization composition When one of the polyolefin or polyvinylidene fluoride contained in the second polymerization composition contains polyvinylidene fluoride, it does not substantially contain a polyolefin.

Accordingly, another object of the present invention is to provide an overcurrent protection device including a first electrode, a second electrode, and a multilayer structure. The multilayer structure is located between the first electrode and the second electrode, and includes a first PTC polymer material layer and a second PTC polymer material layer, wherein one PTC polymer material layer is stacked on another PTC polymer material Bonded on the layers and bonded to each other. The first PTC polymer material layer includes a first polymer substrate and a particulate conductive filler dispersed in the first polymer substrate. The first polymer substrate is prepared from a first polymerization composition comprising polyvinylidene fluoride and a polyolefin, and the weight ratio of the polyvinylidene fluoride to the polyolefin ranges from 1:9 to 9: 1. The second PTC polymer material layer includes a second polymer substrate and a particulate conductive filler dispersed in the second polymer substrate. The second polymeric substrate is prepared from a second polymeric composition comprising at least one of a polyolefin and polyvinylidene fluoride. When the second polymerization composition contains a polyolefin and polyvinylidene fluoride, the weight ratio of the polyvinylidene fluoride to the polyolefin of the second polymerization composition is not in the range of 1:9 to 9:1. . The overcurrent protection device has a trip surface temperature range of 110 to 150 ° C and a collapse voltage range of 30 to 100 V.

1, 82‧‧‧ first electrode

2, 83‧‧‧ second electrode

3‧‧‧Multilayer structure

31‧‧‧First PTC polymer material layer

32‧‧‧Second PTC polymer material layer

33‧‧‧ Third PTC polymer material layer

81‧‧‧ PTC polymer material layer

Other features and advantages of the present invention will be apparent from the description of the drawings, wherein: FIG. 1 is a perspective view illustrating a conventional PTC overcurrent protection device; and FIG. 2 is a perspective view illustrating the PTC of the present invention. A first preferred embodiment of the overcurrent protection device; FIG. 3 is a perspective view showing a second preferred embodiment of the PTC overcurrent protection device of the present invention; and FIG. 4 is a related diagram illustrating the second embodiment and comparison The relationship between the temperature and the resistance of the test samples of Examples 1-3; and FIG. 5 is a relationship diagram illustrating the test samples of Example 2 and Comparative Example 1-3. The relationship between the temperature of the product and the proportion of the recession.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 2, a first preferred embodiment of the overcurrent protection device of the present invention comprises a first electrode 1 and a second electrode 2, and a multilayer structure 3 between the first electrode 1 and the second electrode 2. The multilayer structure 3 includes a first PTC polymer material layer 31 and a second PTC polymer material layer 32, wherein a PTC polymer material layer is stacked on another PTC polymer material layer and bonded to each other.

The first PTC polymer material layer 31 includes a first polymer substrate and a particulate conductive filler dispersed in the first polymer substrate, the first polymer substrate being composed of a first polymer composition be made of

The second PTC polymer material layer 32 includes a second polymer substrate and a particulate conductive filler dispersed in the second polymer substrate. In the preferred embodiment, the second polymeric substrate is made from a second polymeric composition.

In the preferred embodiment, one of the first polymeric composition and the second polymeric composition comprises polyvinylidene fluoride and a polyolefin, and the other contains a polyolefin or polyvinylidene fluoride. When the first polymerization composition and the second polymerization composition contain polyolefin or one of polyvinylidene fluoride containing polyolefin, it does not substantially contain polyvinylidene fluoride; when the first polymerization composition When one of the polyolefin or polyvinylidene fluoride contained in the second polymerization composition contains polyvinylidene fluoride, it does not substantially contain a polyolefin.

Preferably, the first polymeric composition and the second polymeric composition each further comprise a grafted polyolefin.

Preferably, the first polymer composition and the second polymer composition comprise one of polyvinylidene fluoride and a polyolefin, and the weight ratio of the polyvinylidene fluoride to the polyolefin ranges from 1:9 to 9. :1.

Preferably, according to ASTM D-1238, the melt flow rate of the polyvinylidene fluoride is measured to be in the range of 0.5 g/10 min under the conditions of a temperature of 230 ° C and a loading of 12.5 kg. Up to 30g/10min.

Preferably, the polyvinylidene fluoride has a melting point in the range of 140 to 180 °C.

Preferably, the particulate conductive filler of the first polymeric composition and the second polymeric composition is carbon blake.

Preferably, the polyolefin is polyethylene.

Preferably, the first PTC polymer material layer contains 4.7 to 42.3 wt% of polyvinylidene fluoride and 4.7 to 42.3 wt% of polyolefin based on 100 wt% of the total weight of the first PTC polymer material layer. .

Preferably, the second PTC polymer material layer contains 23.5 to 45.0% by weight of the polyolefin based on 100% by weight of the total weight of the second PTC polymer material layer.

Referring to FIG. 3, a second preferred embodiment of the overcurrent protection device of the present invention comprises a first electrode 1 and a second electrode 2, and a multilayer structure 3 between the first electrode 1 and the second electrode 2. The multilayer structure 3 includes a first PTC polymer material layer 31, a second PTC polymer material layer 32, and a third A layer of PTC polymer material 33 in which a layer of PTC polymer material is stacked on another layer of PTC polymer material and bonded to each other. The first PTC polymer material layer 31 is the same as the second PTC polymer material layer 32 and the first preferred embodiment. In the preferred embodiment, the third PTC polymer material layer 33 is stacked on the side of the first PTC polymer material layer 31 opposite to the second PTC polymer material layer 32, and includes a third polymer. a substrate and a particulate electrically conductive filler dispersed in the third polymeric substrate, the third polymeric substrate being prepared from a third polymeric composition.

In certain preferred embodiments, the first polymeric composition comprises polyvinylidene fluoride and a polyolefin, and the third polymeric composition comprises a polyolefin or polyvinylidene fluoride.

In certain preferred embodiments, the first polymeric composition comprises polyvinylidene fluoride or a polyolefin, and the third polymeric composition comprises a polyolefin and polyvinylidene fluoride.

The structure of the third preferred embodiment of the overcurrent protection device of the present invention is similar to that of the first preferred embodiment, except that in the preferred embodiment, the first polymeric composition and the second polymeric composition All contain polyolefin and polyvinylidene fluoride. The weight ratio of the polyvinylidene fluoride to the polyolefin of the first polymeric composition ranges from 1:9 to 9:1, and the polyvinylidene fluoride of the second polymeric composition and the weight of the polyolefin The ratio is not in the range of 1:9 to 9:1.

The overcurrent protection device of each of the preferred embodiments has a tripping surface temperature range of 110 to 150 ° C and a collapse voltage range of 30 to 100 V.

The invention will be further illustrated by the following examples, but It is to be understood that the examples are for illustrative purposes only and are not to be construed as limiting.

Example

Eight formulations (polymeric compositions) were used to prepare the PTC polymer material layers of the following examples and comparative examples (see Table 1).

The materials used for the eight formulations included: HDPE as a polyolefin (purchased from Taiwan Plastics Co., Ltd.; model HDPE9002; weight average molecular weight 150,000 g/mole; according to ASTM D-1238, at 230 ° C, loaded as Grafted HDPE as a grafted polyolefin under the condition of 12.5 kg (45 g/10 min) (purchased from DuPont; model MB100D; weight average molecular weight 80,000 g/mole; according to ASTM D-1238, at temperature Carbon black as a particulate conductive filler at 230 ° C under a load of 12.5 kg, purchased from Columbia Chemical Company; model Raven 430UB; DBP/D 0.95; bulk density 0.53 g/cm ³ ), and PVDF (purchased from Arkema; model Kynar 761; melting point 170 ° C; at a temperature of 230 ° C, loading of 12.5 kg, melt flow rate of 3.0 g/10 min)

<Example 1 (E1)>

A first sheet of PTC polymer material (as a first PTC polymer material layer) is prepared from Formulation (1) comprising 1.175 g of HDPE (purchased from Taiwan Plastics Industry Co., Ltd.; model HDPE9002; The weight average molecular weight is 150,000 g/mole; according to ASTM D-1238, at a temperature of 230 ° C, a loading of 12.5 kg, a melt flow rate of 45 g/10 min), 1.175 g of a carboxylic acid anhydride Grafted) HDPE polyethylene (purchased from DuPont; model MB100D; weight average molecular weight 80,000 g/mole; melt flow rate 75 g/10 min according to ASTM D-1238 at 230 ° C and 12.5 kg loading) ), 21.15 g of PVDF (purchased from Arkema; model Kynar 761; melting point 170 ° C; melt flow rate of 3.0 g/10 min at 230 ° C, loading of 12.5 kg), and 26.5 g of carbon black particles [purchased from Columbia Chemical Company; trade name Raven 430UB; average particle size 82nm; DBP-oil absorption is 75cc/100g; volatile content 1.0wt%; conductivity 2.86×10 ⁴ m ^-1 Ω ^{- 1} ]. Formulation (1) was mixed in a Brabender mixer. The mixing temperature was 200 ° C, the stirring rate was 30 rpm, and the mixing time was 10 minutes. The mixed mixture was subjected to hot pressing to form a first sheet (as a first PTC polymer material layer) of a PTC polymer material having a thickness of 0.175 mm. The hot pressing temperature was 200 ° C, the hot pressing time was 4 minutes, and the hot pressing pressure was 80 kg/cm ² .

A second sheet of PTC polymer material (as a second layer of PTC polymer material) is prepared from Formulation (7) and is prepared in a similar manner to the first sheet of the PTC polymer material.

The copper foil sheets respectively serving as the first electrode layer 1 and the second electrode layer 2 are respectively connected to opposite sides of the stack of the first PTC polymer material layer and the second PTC polymer material layer, and at 200 ° C and The sandwiched PTC laminate was formed by hot pressing at 80 kg/cm ² for 4 minutes. The PTC laminate was cut into test samples having a size of 8 mm x 8 mm. Each test sample was exposed to a cobalt-60 source with a total dose of 50 kGy.

The average resistance of the test sample of Example 1 at room temperature is shown in Table 2.

<Examples 2 to 6, 9 and 10 (E2 to E6, E9 and E10)>

The preparation process and conditions of the test samples of Examples 2 to 6, 9 and 10 (E2 to E6, E9 and E10), except that the composition of the first sheet of the PTC polymer material and the second sheet were different, Both are similar to the embodiment 1.

The formulations of E2 to E6, E9 and E10 used to form the PTC laminate are shown in Table 2. The average electrical resistance of the test samples of Examples 2 to 6, 9 and 10 is shown in Table 2.

<Examples 7 and 8 (E7 and E8)>

The preparation process and conditions of the test samples of Examples 7 and 8 (E7 and E8), except that each of the PTC laminates of Examples 7 and 8 further comprises a third sheet of PTC polymer material, 1 is similar.

The compositions of the PTC laminates of Examples 7 and 8 are shown in Table 2. The average resistance of the test samples of Examples 7 and 8 is shown in Table 2.

<Comparative Examples 1 to 4 (CE1 to CE4)>

The preparation procedures and conditions of the test samples of Comparative Examples 1 to 4 (CE1 to CE4) were similar to those of Example 1 except that each of the comparative examples had only one sheet of the PTC polymer material layer.

The compositions of the PTC laminates of Comparative Examples 1 to 4 are shown in Table 2. The average resistance of the test samples of Comparative Examples 1 to 4 is shown in Table 2.

<Comparative Example 5 (CE5)>

The preparation process and conditions of the first sheet and the second sheet of Comparative Example 5 (CE5), except that the first sheet and the second sheet of Comparative Example 5 were prepared by the formulation (7) and the formulation (8), respectively. Both are similar to the embodiment 1. Since the second sheet is made of a formulation (8) containing PVDF and no polyolefin, it is substantially non-tacky. Therefore, the first sheet and the second sheet cannot be laminated to form a PTC laminate.

<Comparative Examples 6 and 7 (CE6 and CE7)>

The preparation procedures and conditions of the test samples of Comparative Examples 6 and 7 (CE6 and CE7) were similar to those of Example 1 except that the first sheet of the PTC polymer material was different from the formulation used for the second sheet.

The compositions of the PTC laminates of Comparative Examples 6 and 7 are shown in Table 2. The average resistance of the test samples of Comparative Examples 6 and 7 is shown in Table 2.

Performance Testing

Resistance at different temperatures

Ten test samples of E1~E10 and CE1~CE7 were tested to determine the resistance of the test samples of E1~E10 and CE1~CE7 between 25 and 185 °C.

The resistance test of each test sample was completed at a fixed rate of 2 ° C/min, and each test sample was gradually heated from an initial temperature of 25 ° C to a final temperature of 185 ° C. The resistance of each test sample in E1~E10 and CE1~CE7 at room temperature was recorded. The resistance test results are shown in Table 3, and E2 The relationship between temperature and resistance of the test samples with CE1~CE3 is shown in Fig. 4. At the same temperature, the higher the resistance of the PTC laminate, the higher the working voltage of the PTC laminate. The results show that Examples 1 to 10 can be operated at a higher operating voltage than Comparative Examples 1 to 7. For example, E2 has a resistance of 24.58 ohms at 140 ° C and a resistance of 1313.05 ohm at 170 ° C, a resistance of 18.98 ohms at 140 ° C higher than that of Comparative Example 1, and a resistance of 47.86 ohms at 170 ° C.

Thermal derating test

Each test sample in E1~E10 and CE1~CE7 is subjected to thermal decay test to determine the thermal decay ratio of E1~E10 and CE1~CE7 (operating current at test temperature/operating current at 25 °C× 100%). The thermal decay test was performed by measuring the operating current of each test sample at -40 ° C, 25 ° C, 85 ° C, and 125 ° C.

The results of the thermal decay test are shown in Table 3. The relationship between the temperature of E2 and CE1~CE3 test samples and the decay ratio is shown in Fig. 5.

Thermal runaway test

Five test samples of E1~E10 and CE1~CE7 were used for thermal runaway test. The thermal runaway test of each test sample is sufficient to burn each test sample at a fixed current of 100 A, and the test sample is gradually increased from an initial voltage of 20 Vdc to a final voltage of 1000 Vdc. The applied voltage is an increase in the amount of 5 Vdc per step and the duration of each step is 2 minutes (ie, each new applied voltage lasts 2 minutes). The maximum tolerable voltage (ie, collapse voltage) of each test sample of E1~E10 and CE1~CE7 was recorded. Thermal runaway test results are shown in Table 3.

The results of the thermal decay test (see Table 3) show that the test current of the CE1 test sample at 125 ° C is close to zero due to the lack of PVDF in the PTC polymer material layer of CE1. Only the test sample of CE3 and CE4 of a polymer material layer had an operating current close to zero at 125 °C. Each test sample of CE1, CE3, and CE4 can only be operated between the operating temperature ranges of -40 to 85 °C.

Both the first PTC polymer material layer and the second PTC polymer material layer comprise CE6 and CE7 of polyolefin and PVDF, and the test current of the test sample at 125 ° C is also close to zero. Each test sample of CE6 and CE7 can only be operated between -40 and 85 °C operating temperature range.

The operating current of the test samples of E1~E10 at 125 °C is still dimensional Hold at 20% or more. Each of the test samples E1 to E10 (one of which contains PVDF) has an operating temperature range of -40 to 125 °C.

The thermal runaway test results (see Table 3) show that the collapse voltage of E1~E10 (90 to 100V) is higher than CE1~CE4 (30 to 60V), indicating that the overcurrent protection device of the present invention can operate at a higher voltage.

In summary, since the overcurrent protection device of the present invention includes the first PTC polymer material layer and the second PTC polymer material layer, and at least one of them contains PVDF and polyolefin, the disadvantages of the foregoing prior art can be reduced. Therefore, the object of the present invention can be achieved.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the equivalent equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still The scope of the invention is covered.

1‧‧‧first electrode

2‧‧‧second electrode

3‧‧‧Multilayer structure

31‧‧‧First PTC polymer material layer

32‧‧‧Second PTC polymer material layer

Claims (12)

An overcurrent protection device comprising: a first electrode and a second electrode; and a multilayer structure between the first electrode and the second electrode, and comprising a first PTC polymer material layer and a second PTC polymer material a layer, wherein a layer of PTC polymer material is stacked on another PTC polymer material layer and bonded to each other; wherein the first PTC polymer material layer comprises a first polymer substrate and a dispersion of the first polymer a particulate electrically conductive filler in the substrate, the first polymeric substrate being made from a first polymeric composition; the second PTC polymeric material layer comprising a second polymeric substrate and a second dispersed in the second a particulate electrically conductive filler in a polymeric substrate, the second polymeric substrate being prepared from a second polymeric composition; one of the first polymeric composition and the second polymeric composition comprising a polypyramid Difluoroethylene and polyolefin, the other contains polyolefin or polyvinylidene fluoride; when the first polymeric composition and the second polymeric composition contain polyolefin or polyvinylidene fluoride, one contains polyolefin When it is substantially free of polyvinylidene fluoride ; When the first polymeric composition and the second polymer composition containing a polyolefin or polyvinylidene fluoride containing one of polyvinylidene fluoride, which does not substantially contain a polyolefin. The overcurrent protection device according to claim 1, wherein the first polymerization composition and the second polymerization composition each further comprise a graft polyolefin. The overcurrent protection device according to claim 1, wherein the first polymerization composition and the second polymerization composition comprise one of polyvinylidene fluoride and polyolefin, and polyvinylidene fluoride and polyolefin. The weight ratio ranges from 1:9 to 9:1. The overcurrent protection device according to claim 1, wherein the melt flow rate range of the polyvinylidene fluoride is measured according to ASTM D-1238 at a temperature of 230 ° C and a load of 12.5 kg. It is from 0.5 g/10 min to 30 g/10 min. The overcurrent protection device according to claim 1, wherein the polyvinylidene fluoride has a melting point in the range of 140 to 180 °C. The overcurrent protection device of claim 1, wherein the particulate conductive filler of the first polymeric composition and the second polymeric composition is carbon black. The overcurrent protection device according to claim 1, wherein the polyolefin of the first polymerization composition and the second polymerization composition is polyethylene. The overcurrent protection device according to claim 1, wherein the first PTC polymer material layer contains 4.7 to 42.3 wt% of polyvinylidene fluoride based on 100 wt% of the total weight of the first PTC polymer material layer. Ethylene and 4.7 to 42.3 wt% of polyolefin. The overcurrent protection device according to claim 1, wherein the second PTC polymer material layer contains 23.5 to 45.0% by weight of the polyolefin based on 100% by weight of the total weight of the second PTC polymer material layer. The overcurrent protection device of claim 1, wherein the multilayer structure further comprises a third PTC polymer material layer stacked on the first PTC polymer material layer, the third PTC polymer material layer comprising Third gathering a substrate and a particulate conductive filler dispersed in the third polymer substrate, the third polymer substrate being prepared from a third polymer composition comprising a polydisperse Fluorine and polyolefin, the third polymer composition contains polyolefin or polyvinylidene fluoride. The overcurrent protection device of claim 1, wherein the multilayer structure further comprises a third PTC polymer material layer stacked on the first PTC polymer material layer, the third PTC polymer material layer comprising a third polymer substrate and a particulate conductive filler dispersed in the third polymer substrate, the third polymer substrate being prepared from a third polymer composition, the first polymer composition comprising a poly Part of vinylidene fluoride or polyolefin, the third polymeric composition comprising polyolefin and polyvinylidene fluoride. An overcurrent protection device comprising: a first electrode and a second electrode; and a multilayer structure between the first electrode and the second electrode, and comprising a first PTC polymer material layer and a second PTC polymer material a layer, wherein a layer of PTC polymer material is stacked on another PTC polymer material layer and bonded to each other; wherein the first PTC polymer material layer comprises a first polymer substrate and a dispersion of the first polymer a particulate electrically conductive filler in a substrate, the first polymeric substrate being prepared from a first polymeric composition comprising polyvinylidene fluoride and a polyolefin, the weight ratio of the polyvinylidene fluoride to the polyolefin The range of 1:9 to 9:1; the second PTC polymer material layer comprises a second polymer substrate and a particulate conductive filler dispersed in the second polymer substrate, the first The second polymer substrate is prepared from a second polymer composition comprising at least one of a polyolefin and polyvinylidene fluoride; when the second polymer composition comprises a polyolefin and a poly In the case of vinylidene fluoride, the weight ratio of the polyvinylidene fluoride to the polyolefin of the second polymer composition is not in the range of 1:9 to 9:1; and the surface temperature of the overcurrent protection device The range is 110~150°C, and the collapse voltage range is 30~100V.