EP0747910A2 - Résistance PTC - Google Patents

Résistance PTC Download PDF

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Publication number
EP0747910A2
EP0747910A2 EP96810322A EP96810322A EP0747910A2 EP 0747910 A2 EP0747910 A2 EP 0747910A2 EP 96810322 A EP96810322 A EP 96810322A EP 96810322 A EP96810322 A EP 96810322A EP 0747910 A2 EP0747910 A2 EP 0747910A2
Authority
EP
European Patent Office
Prior art keywords
filler
ptc
ptc resistor
particles
fraction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96810322A
Other languages
German (de)
English (en)
Other versions
EP0747910A3 (fr
Inventor
Gerd Maidorn
Ralf Dr. Strümpler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Research Ltd Switzerland
ABB Research Ltd Sweden
Original Assignee
ABB Research Ltd Switzerland
ABB Research Ltd Sweden
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ABB Research Ltd Switzerland, ABB Research Ltd Sweden filed Critical ABB Research Ltd Switzerland
Publication of EP0747910A2 publication Critical patent/EP0747910A2/fr
Publication of EP0747910A3 publication Critical patent/EP0747910A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/027—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient consisting of conducting or semi-conducting material dispersed in a non-conductive organic material

Definitions

  • the invention is based on a PTC resistor according to the preamble of claim 1.
  • Resistors based on a polymer matrix and a powdery filler made of electrically conductive material with PTC behavior embedded in the polymer matrix are used as current-limiting elements in energy technology uses and serve to limit a short-circuit or overcurrent occurring in a circuit.
  • the PTC resistor is heated by the short-circuit or overcurrent to a critical temperature at which the polymer of the PTC resistor embedding the filler particles changes its phase, for example by melting, and then interrupts the current-carrying percolation paths of the PTC resistor formed by the filler particles.
  • a PTC resistor based on a polymer matrix and a powdery filler of electrically conductive material embedded in the polymer matrix is described in WO-A-91 19 297.
  • the matrix of this resistor is made of a thermoplastic polymer, such as in particular polyethylene. Carbon black with particle sizes of up to 0.1 ⁇ m, metals such as nickel, tungsten, brass or aluminum, Borides, such as TiB 2 , nitrides, such as ZrN, oxides, such as TiO, or carbides, such as TaC, with particle sizes of up to 100 ⁇ m are used. Due to the material composition and suitable manufacturing processes, the known PTC resistor has a specific resistance between 30 and 50 m ⁇ ⁇ cm in the cold conducting state and can then be loaded with relatively high nominal currents.
  • the PTC behavior of the resistor which is important for current limitation in a power engineering circuit, it is not only its specific resistance in the cold conducting state that is important, but also material-specific properties that are significant, which quickly when the current through the resistor rises above a limit value Limit this current without the resistance being heated to an unacceptably high level.
  • this can lead to the PTC resistor forming locally overheated areas, so-called "hot spots", approximately in the middle between the contact connections.
  • the PTC resistor switches to the high-resistance state earlier than at unheated areas.
  • the total voltage across the PTC resistor then drops over a relatively small distance at the location of the highest resistance.
  • the associated high electrical field strength can then lead to breakdowns and damage to the PTC resistor.
  • the invention is based on the object of providing a PTC resistor of the type mentioned at the outset, which enables particularly rapid limitation of a short-circuit or overcurrent flowing in a circuit.
  • the PTC resistor according to the invention is characterized in that it responds extremely quickly to a short-circuit or overcurrent and can therefore limit this current at an early point in time.
  • the PTC resistor according to the invention absorbs relatively little energy and is largely spared from impermissibly high thermal and electrical loads. Overheated local areas are therefore generally avoided. These favorable properties result from the suitably selected and dimensioned filler.
  • a short-circuit or overcurrent I (t) heats the PTC resistor to its critical temperature T C , at which the PTC transition takes place and the current is limited.
  • the time ⁇ t required for a homogeneous material to limit the short-circuit or overcurrent depends on the specific resistance r, the specific density d mass and the specific heat c P of the material of the PTC resistor as well as its cross section A and its length 1 between its connection electrodes .
  • the energy converted in the response period ⁇ t in the PTC resistor must be at least as large as the energy which is necessary to heat the material of the resistor from the ambient temperature T to the transition temperature T c .
  • the energy supplied by the short-circuit or overcurrent is not converted homogeneously in the PTC resistor.
  • the resistor has percolating current paths formed by the conductive particles.
  • the greatest electrical resistance and thus also the greatest conversion from electrical to thermal energy takes place on electrical Contact between the individual filler particles instead.
  • the thermal energy generated at the contact points heats the polymer embedding the filler particles. If the filler particles are relatively large, for example larger than 100 ⁇ m, relatively large gaps filled with polymer form between the individual particles. If, on the other hand, the filler particles are relatively small, only relatively small gaps filled with polymer form between the individual particles.
  • the energy converted at the contact points can heat the polymer located in the small gaps much faster than the polymer provided in the larger gaps.
  • the temperature T c required to carry out the PTC transition is therefore reached more quickly with smaller filler particles.
  • the major part of the filler particles must not be less than 10 ⁇ m, since otherwise the specific resistance becomes too great.
  • thermoplastic PTC polymer such as, in particular, polyethylene
  • electrically conductive filler powder using a process customary in the production of PTC resistors, and cuboidal resistance bodies with end faces smoothed out by lapping or polishing from the resulting mixture at elevated temperature and pressure pressed. Contact connections were soldered to the end faces.
  • the length 1 of the resistors was in the centimeter range, the cross-sectional area A was in the square centimeter range. Typical values for 1 and A were approx. 0.5 to approx. 2 cm and 0.3 cm 2 .
  • Polyethylene was used as the starting material for the polymer.
  • an epoxy or some other thermoplastic or thermosetting polymer can also be used.
  • Powdery TiB 2 with different particle sizes was used as filler, in particular with average particle sizes between 100 and 200 ⁇ m, between 71 and 90 ⁇ m, between 63 and 71 ⁇ m, between 50 and 63 ⁇ m, between 32 and 50 ⁇ m, between 32 and 45 ⁇ m , between 10 and 30 ⁇ m, between 1 and 5 ⁇ m and with average particle sizes smaller than 45 ⁇ m, of which Particles were 10% by weight less than 4 ⁇ m, 20% by weight less than 8 ⁇ m, 50% by weight less than 15 ⁇ m and 90% by weight less than 20 ⁇ m.
  • the filler may also be another conductive boride such as ZrB 2 , a conductive carbide such as TiC, VC or SiC, a conductive nitride such as ZrN, a conductive oxide such as RUO 2 or VO, or a conductive silicide, such as MoSi 2 or WSi 2 , and / or a metal or an alloy containing this metal, for example based on nickel, silver, tungsten, cobalt, copper, aluminum, zinc, tin or molybdenum.
  • a conductive boride such as ZrB 2
  • a conductive carbide such as TiC, VC or SiC
  • a conductive nitride such as ZrN
  • a conductive oxide such as RUO 2 or VO
  • a conductive silicide such as MoSi 2 or WSi 2
  • the individual PTC resistors were designed in such a way that they had the same cross-section A with the same chemical composition of polymer and filler and differed from one another by length 1 and above all by the size of the powdery filler.
  • PTC resistance samples A to N were produced with the mean filler particle sizes and filler quantities as well as geometric dimensions given in the table below.
  • each of the resistance samples A - N to be examined was installed in a circuit in which a capacitor bank with a capacity of 7.5 was charged as the short-circuit current source in the samples A-D to 200 V and in the samples E - N to 400 V. mF was available.
  • the inductance of the circuit was 4.5 ⁇ H, which after short-circuiting the circuit with an ignitron led to a resonant circuit frequency of approx. 800 Hz.
  • the resistance samples A - N were each protected from overvoltages by varistors connected in parallel. Samples E, F, H, J and L - N were protected against external flashovers by immersion in transformer oil and samples G and K were each protected by applying a silicone coating.
  • the current I max is the highest measured current that has flowed through the respective test resistor during the short-circuit current test. The higher its value, the later the PTC transition and thus the current limitation started.
  • [Energy consumption ⁇ U (t) ⁇ I (t) dt]
  • the energy consumption is a measure of the switching behavior of the PTC resistors.
  • the switching capacity of the PTC resistors is all the better the lower the energy consumption under comparable conditions.
  • sample B and C with particle sizes between 63 and 71 ⁇ m or 32 and 45 ⁇ m
  • the short-circuit current is sometimes limited considerably earlier (with sample C approx. 50 ⁇ s, ie approx. 25% rather than with sample A).
  • the short-circuit current is no longer as high as with sample A (with sample C with 1200 A only about 90% of the value of sample A).
  • the energy absorbed by the resistors when limiting the current is lower. In sample B this energy is approx. 15% and in sample C approx. 45% smaller than in sample A.
  • PTC resistors which mainly contain filler particles with average diameters larger than 100 ⁇ m
  • PTC resistors in which the predominant volume fraction of the filler has particles with average diameters smaller than approx. 100 ⁇ m or better smaller than approx. 70 ⁇ m, have a significantly improved switching behavior on.
  • a particularly favorable switching behavior with low energy consumption, shorter Response time and small peak value of the current I max carried in the resistor is achieved when the predominant volume fraction of the filler has particles with particle sizes smaller than 30 ⁇ m or even smaller than 20 ⁇ m.
  • the average size of the particles provided in the predominant volume fraction must not be chosen too small, since then among other things the specific resistance and thus also the cold resistance of a PTC resistor made from such a material increases too much.
  • sample D in which the filler particles had average particle sizes between 1 and 5 ⁇ m.
  • practically 50% more filler had to be mixed into the polymer with Sample D with a volume fraction of approx. 60% than with the others Rehearse.
  • Current limitation through a PTC transition could not be achieved with such a resistor at a test voltage of 200 V.
  • the limit current I max given in the table above is only due to the high cold resistance of 226 m ⁇ and not due to a PTC transition.
  • a further improvement in the response behavior of the PTC resistor according to the invention is achieved if the filler particles are hollow or have a low mass, since particularly rapid heating of the polymer can then be achieved due to a relatively low specific heat.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
EP96810322A 1995-06-08 1996-05-22 Résistance PTC Withdrawn EP0747910A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19520869 1995-06-08
DE1995120869 DE19520869A1 (de) 1995-06-08 1995-06-08 PTC-Widerstand

Publications (2)

Publication Number Publication Date
EP0747910A2 true EP0747910A2 (fr) 1996-12-11
EP0747910A3 EP0747910A3 (fr) 1997-09-10

Family

ID=7763881

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96810322A Withdrawn EP0747910A3 (fr) 1995-06-08 1996-05-22 Résistance PTC

Country Status (4)

Country Link
EP (1) EP0747910A3 (fr)
JP (1) JPH097802A (fr)
CN (1) CN1140318A (fr)
DE (1) DE19520869A1 (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5929744A (en) * 1997-02-18 1999-07-27 General Electric Company Current limiting device with at least one flexible electrode
US5977861A (en) * 1997-03-05 1999-11-02 General Electric Company Current limiting device with grooved electrode structure
US6124780A (en) * 1998-05-20 2000-09-26 General Electric Company Current limiting device and materials for a current limiting device
US6133820A (en) * 1998-08-12 2000-10-17 General Electric Company Current limiting device having a web structure
US6191681B1 (en) 1997-07-21 2001-02-20 General Electric Company Current limiting device with electrically conductive composite and method of manufacturing the electrically conductive composite
US6290879B1 (en) 1998-05-20 2001-09-18 General Electric Company Current limiting device and materials for a current limiting device
US6323751B1 (en) 1999-11-19 2001-11-27 General Electric Company Current limiter device with an electrically conductive composite material and method of manufacturing
US6373372B1 (en) 1997-11-24 2002-04-16 General Electric Company Current limiting device with conductive composite material and method of manufacturing the conductive composite material and the current limiting device
US6535103B1 (en) 1997-03-04 2003-03-18 General Electric Company Current limiting arrangement and method
WO2018080441A1 (fr) * 2016-10-25 2018-05-03 Hewlett-Packard Development Company, L.P. Capteurs de température

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19800470A1 (de) * 1998-01-09 1999-07-15 Abb Research Ltd Widerstandselement
US6128168A (en) 1998-01-14 2000-10-03 General Electric Company Circuit breaker with improved arc interruption function
US6144540A (en) 1999-03-09 2000-11-07 General Electric Company Current suppressing circuit breaker unit for inductive motor protection
US6157286A (en) 1999-04-05 2000-12-05 General Electric Company High voltage current limiting device
CN101935418B (zh) * 2009-06-30 2013-05-29 比亚迪股份有限公司 正温度系数材料及其制备方法及含该材料的热敏电阻及其制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0373633A2 (fr) * 1988-12-14 1990-06-20 Idemitsu Kosan Company Limited Polyéthers copolymères, procédé de leur préparation, composition les contenant, leurs objets formés et leur application
EP0590347A1 (fr) * 1992-10-01 1994-04-06 Abb Research Ltd. Résistance à comportement PTC

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1604735A (en) * 1978-04-14 1981-12-16 Raychem Corp Ptc compositions and devices comprising them
US4616125A (en) * 1984-02-03 1986-10-07 Eltac Nogler & Daum Kg Heating element
JPH0777161B2 (ja) * 1986-10-24 1995-08-16 日本メクトロン株式会社 Ｐｔｃ組成物、その製造法およびｐｔｃ素子
SE468026B (sv) * 1990-06-05 1992-10-19 Asea Brown Boveri Saett att framstaella en elektrisk anordning
DE4221309A1 (de) * 1992-06-29 1994-01-05 Abb Research Ltd Strombegrenzendes Element

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0373633A2 (fr) * 1988-12-14 1990-06-20 Idemitsu Kosan Company Limited Polyéthers copolymères, procédé de leur préparation, composition les contenant, leurs objets formés et leur application
EP0590347A1 (fr) * 1992-10-01 1994-04-06 Abb Research Ltd. Résistance à comportement PTC

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JOURNAL OF MATERIALS SCIENCE, Bd. 26, Nr. 1, 1.Januar 1991, Seiten 145-154, XP000371800 SHROUT T R ET AL: "COMPOSITE PTCR THERMISTORS UTILIZING CONDUCTING BORIDES, SILICIDES, AND CARBIDE POWDERS" *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5929744A (en) * 1997-02-18 1999-07-27 General Electric Company Current limiting device with at least one flexible electrode
US6535103B1 (en) 1997-03-04 2003-03-18 General Electric Company Current limiting arrangement and method
US5977861A (en) * 1997-03-05 1999-11-02 General Electric Company Current limiting device with grooved electrode structure
US6191681B1 (en) 1997-07-21 2001-02-20 General Electric Company Current limiting device with electrically conductive composite and method of manufacturing the electrically conductive composite
US6540944B2 (en) 1997-11-24 2003-04-01 General Electric Company Current limiting device with conductive composite material and method of manufacturing the conductive composite material and the current limiting device
US6373372B1 (en) 1997-11-24 2002-04-16 General Electric Company Current limiting device with conductive composite material and method of manufacturing the conductive composite material and the current limiting device
US6124780A (en) * 1998-05-20 2000-09-26 General Electric Company Current limiting device and materials for a current limiting device
US6290879B1 (en) 1998-05-20 2001-09-18 General Electric Company Current limiting device and materials for a current limiting device
US6366193B2 (en) 1998-05-20 2002-04-02 General Electric Company Current limiting device and materials for a current limiting device
US6133820A (en) * 1998-08-12 2000-10-17 General Electric Company Current limiting device having a web structure
US6323751B1 (en) 1999-11-19 2001-11-27 General Electric Company Current limiter device with an electrically conductive composite material and method of manufacturing
US6711807B2 (en) 1999-11-19 2004-03-30 General Electric Company Method of manufacturing composite array structure
WO2018080441A1 (fr) * 2016-10-25 2018-05-03 Hewlett-Packard Development Company, L.P. Capteurs de température
US11199456B2 (en) 2016-10-25 2021-12-14 Hewlett-Packard Development Company, L.P. Temperature sensors

Also Published As

Publication number Publication date
EP0747910A3 (fr) 1997-09-10
JPH097802A (ja) 1997-01-10
CN1140318A (zh) 1997-01-15
DE19520869A1 (de) 1996-12-12

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