Thermal sensing wire and thermal sensing technology

Abstract

A thermal sensor wire may include: a thermal sensing portion extending along the wire axis of the thermal sensor wire; and a carrier portion extending along the wire axis and adjacent to the thermal sensing portion, wherein the thermal sensing portion includes a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of circuit protection devices (including battery devices). Background Art

[0002] Materials such as polymer positive temperature coefficient (PPTC) and negative temperature coefficient (NTC) devices can be used as overcurrent or overtemperature protection devices, as well as current or temperature sensors, in a variety of applications. In known configurations, PPTC materials can be placed between a pair of electrodes to limit current or sense the temperature of a component. However, greater flexibility in the placement of PPTC and NTC devices can open up new uses or improve control in existing applications. Summary of the Invention

[0003] In one embodiment, a thermal sensor wire is provided, which may include: a thermal sensing portion extending along the wire axis of the thermal sensor wire; a carrier portion extending along the wire axis and adjacent to the thermal sensing portion, wherein the thermal sensing portion includes a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material.

[0004] In another embodiment, a method for forming a thermal sensor wire is provided. The method may include forming a carrier portion of the thermal sensor wire, the carrier portion extending along the length of the thermal sensor wire. The method may also include forming a thermal sensing material, and then forming a thermal sensing portion of the thermal sensor wire, the thermal sensing portion extending along the length of the thermal sensor wire and adjacent to the carrier portion. The thermal sensing material may be formed from a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material, characterized in that a thermal transition occurs within a target temperature range, wherein the carrier portion includes a carrier material that does not undergo a thermal transition within the target temperature range.

[0005] In another embodiment, a device may include a battery portion and a thermal sensor wire disposed in contact with the battery portion. The thermal sensor wire may include a thermal sensing portion extending along a wire axis of the thermal sensor wire; and a carrier portion extending along the wire axis and adjacent to the thermal sensing portion, wherein the thermal sensing portion includes a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figures 1A-1E Various thermal sensor wires arranged in accordance with different embodiments of the present disclosure are depicted in cross-sectional views;

[0007] Figure 1Fshows a side view of a thermal sensor wire according to various embodiments;

[0008] Figure 1G shows a graph showing the relationship between resistivity and temperature of a PPTC-based thermal sensor wire according to an embodiment of the present disclosure;

[0009] Figure 2 An embodiment of a thermal sensor wire within a device according to an embodiment of the present disclosure is depicted;

[0010] Figure 3 An embodiment of an apparatus for forming a thermal sensor wire is shown;

[0011] Figure 4 A thermal sensor wire according to a further embodiment of the present disclosure is depicted; and

[0012] Figure 5 A process flow according to other embodiments of the present disclosure is described. DETAILED DESCRIPTION

[0013] The present embodiments will be described more fully hereinafter with reference to the accompanying drawings, which show exemplary embodiments. The foregoing embodiments should not be construed as limiting the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. Like numbers in the drawings refer to like elements in various aspects.

[0014] In the following description and / or claims, "above," "superimposed on," "disposed on," and "over" may be used in the following description and claims. "Above," "superimposed on," "disposed on," and "over" may be used to indicate that two or more elements are in direct physical contact with each other. "Above," "superimposed on," "disposed on," and "over" may also mean that two or more elements are in direct contact with each other. For example, "above" may mean that one element is above another element, while the two elements are not in contact with each other and there may be another element or elements between the two elements. Additionally, "and / or" may mean "and," it may mean "or," it may mean "exclusive-or," it may mean "one," it may mean "some, but not all," it may mean "neither," and / or it may mean "both," however, the scope of the claimed subject matter is not limited in this respect.

[0015] In various embodiments, thermal indicator "wires" can be used for distributed temperature sensing. Thermal indicator wires or thermal sensor wires with temperature-sensing elements can be used to sense when a device exceeds a critical temperature. In some examples, the heat causing the excessive temperature may be generated over a large area, while in other embodiments, temperature sensors can be used to detect hot spots.

[0016] In various embodiments, a polymer positive temperature coefficient (PPTC) or negative temperature coefficient (NTC) material may be incorporated as part of a thermal sensing conductor. In short, the thermal sensing conductor described in this embodiment (also referred to herein as a "thermal sensor conductor") can be used to indicate when a target temperature has been reached or exceeded. The thermal sensing conductor can be placed in contact with a body or device where a temperature change (either localized or global) is possible. For the aforementioned devices employing the thermal sensing conductor as a protective measure, the PPTC or NTC material of the thermal sensing conductor can transition from high resistance to low resistance, or vice versa, when the temperature reaches or exceeds the target temperature. An indicator or device coupled to the thermal sensing conductor can convert this resistance change into an alarm or control signal. Thus, the thermal sensing conductor of this embodiment can be used in current embodiments of "digital" PPTC thermal indicators to change resistance from low (normal operation) impedance to high (high temperature) impedance for PTCs and vice versa for NTCs, thereby providing overcurrent and / or overtemperature protection (similar to known PPTC devices).

[0017] Figures 1A-1E Various thermal sensor wires arranged in accordance with different embodiments of the present disclosure are depicted in cross-sectional views. Figure 1A In the figure, a thermal sensor wire 100 is shown according to some embodiments of the present disclosure. The thermal sensor wire 100 may include a thermal sensing portion extending along the wire axis (Z axis of the Cartesian coordinate system shown) of the thermal sensor wire 100. Similarly, the thermal sensor wire 100 may include a carrier portion, which also extends along the wire axis. Figures 1A-1B As shown in the configuration, the thermal sensor wire 100 may include an inner core 104 and an outer core 102, wherein the outer core 102 is disposed circumferentially around the inner core. In this way, both the inner core 104 and the outer core 102 may extend along the wire axis. Figures 1A-1B As shown, the inner core 104 may be in the shape of a rod or a solid cylinder, while the outer core 102 may have a hollow cylinder or a toroidal shape. In some embodiments, the inner core 104 may represent the heat-sensing portion, while the outer core 102 may represent the carrier portion. In other embodiments, the inner core 104 may represent the carrier portion, while the outer core represents the heat-sensing portion.

[0018] The thermal sensing portion of the thermal sensor wire 100 can be formed from any suitable known PPTC material or known NTC material. Non-limiting examples of PPTC materials include polymer composites having a polymer portion and a conductive powder dispersed or interspersed therein. The polymer portion of the PPTC material can be polyvinylidene fluoride (PVDF), HDPE (high / low density polyethylene), polyurethane, ethylene-tetrafluoroethylene copolymer (EFTE), PFA (perfluoroalkoxy), or other polymers, such as polymers having crystalline and amorphous phases. Non-limiting examples of NTC materials include oxides based on nickel, manganese, iron, and the like, silicon, and the like.

[0019] In various embodiments, the carrier portion of the thermal sensor wire can be based on a polymer material, such as one of the aforementioned polymers used in PPTC materials, without a conductive powder. In other embodiments, the carrier portion of the thermal sensor wire can be based on a polymer material, such as one of the aforementioned polymers used in PPTC materials, with a dielectric powder dispersed within the polymer. In additional embodiments, the carrier portion of the thermal sensor wire can be based on other types of polymer materials, such as polyimide, PVC (polyvinyl chloride), acrylic alkyds such as Rambar, polyimide, or other polymers. In other non-limiting embodiments, the carrier portion can be formed from a carrier material including a polymer with a higher temperature (Tg glass transition or Tm melting point higher than other polymers), or a more heavily cross-linked polymer. For example, a polymer with a lower transition temperature can be used for the thermal sensing portion and can be conductive with a high-temperature (polycarbonate-based) polyurethane or a thermally cross-linked polyimide in the carrier portion. The carrier portion can be formed from a higher-temperature PET (polyethylene terephthalate) or PCT (poly(cyclohexanedimethanol)) blend. Other suitable materials for the carrier part could be fibers from ETFE or inorganic fiberglass based fibers, or organic hemp based metal wires with good pinhole free electrical insulation, nylon, polyester or other materials.

[0020] In various embodiments, the thermal sensing portion is designed to display a target transition temperature when a sharp and noticeable change in resistivity occurs. In embodiments using PPTC materials such as thermal sensing materials, the resistivity increase may include an order of magnitude increase, i.e., three orders of magnitude, five orders of magnitude, seven orders of magnitude, etc. In other embodiments where the thermal sensing portion is formed from an NTC material, the resistivity may drop sharply, such as by a factor of 5, 10, 100, etc. The embodiments are not limited thereto. The severity of the transition to resistivity may depend on the properties of the PPTC material or the NTC material. However, in some embodiments, most of the resistivity change may occur in the range of 5°C or 10°C. In Figure 1GIn the example shown, the resistivity of the PPTC-based thermal sensor wire increases by approximately four orders of magnitude (10,000) over a temperature range of 50°C to 60°C. Therefore, the thermal sensor wire can be used as a sensor to indicate when the protected device or body reaches or exceeds a target temperature of approximately 60°C.

[0021] according to Figure 1F As suggested in the

[0015] , the thermal sensor wire 100 can have the same elongated shape as known wires. The thermal sensor wire 100 and other wires described below can have similar mechanical properties to known wires, including plasticity, the ability to be shaped and wrapped around a given object. In various non-limiting embodiments, the thermal sensor wire 100 or other thermal sensor wires described in detail below can have a diameter ranging from 150 μm to 1 cm.

[0022] Go to Figure 2 , shown in the figure is an embodiment of a thermal sensor wire 100 in a device 200, wherein, in addition to the thermal sensor wire 100, the above-mentioned device 200 may further include a battery portion 202. The thermal sensor wire 100 may be wrapped around the battery portion 202, so that many areas of the battery portion 202 are in thermal contact with different parts (segments) of the thermal sensor wire 100. In one embodiment, the transition temperature of the thermal sensor wire 100 is 60°C. When a hot spot appears in any area of ​​the battery portion 202 and the temperature rises to 60°C or above, one or more segments of the thermal sensor wire 100 in thermal contact with the hot spot of the battery portion 202 will experience a sharp and obvious change in resistivity, as described above. Figure 2 As shown, thermal sensor wire 100 can be electrically connected to sensor device 204, representing any suitable circuit system, controller, or indicator, wherein a significant change in the resistance of thermal sensor wire 100 can trigger the generation of a suitable control signal or indicator signal. For example, the device 200 can stop the operation of battery portion 202 upon detecting a hot spot of 60°C, or can generate an alarm signal, such as an audible signal, a visible signal, or both.

[0023] Because the thermal sensor wire 100 can be conveniently placed next to or around many different areas of a device (e.g., the battery portion 202), the thermal sensor wire 100 and other similar wires described in detail below provide a convenient mechanism for detecting thermal events occurring anywhere in a device or body using simple circuitry. Thus, even if the exact location of a thermal event or overtemperature may not be determined, the thermal sensor wire 100 can easily detect a localized event occurring somewhere in the protected body or device, allowing appropriate action to be taken before overheating or widespread heating occurs.

[0024] In the aforementioned Figure 1AIn the embodiment shown, only the inner core 104 and the outer core 102 are shown. However, in additional embodiments, the thermal sensor wire may include a wire coating disposed around the outer core. Figure 1B An embodiment of a thermal sensor wire 110 is shown, including a wire coating 112 disposed around an outer core 102. In various non-limiting embodiments, the wire coating 112 can be formed from an insulator (e.g., the same base polymer as used in the thermal sensing portion) without any added conductive phase; can be formed from an insulator (e.g., the same base polymer as used in the thermal sensing portion) with a dielectric filler; or can be formed from an insulator (e.g., the same base polymer as used in the thermal sensing portion) with the addition of another polymer that can increase TG or increase crosslinking. Examples of other polymeric materials that can be added to a PPTC substrate to form an insulator coating include polycarbonate, PVC, polyimide, PTFE, or other known polymers.

[0025] In some embodiments, the wire coating 112 or similar wire coatings may be specifically arranged to convey information about the contents of the outer core 102 or the inner core 104, as follows: Figure 4 shown. Figure 3 An embodiment of an apparatus 300 for forming a thermal sensor wire, such as thermal sensor wire 110, is shown. Apparatus 300 may represent an extrusion apparatus having a central hole 302 through which inner core 104 is pulled or extruded, a second hole 304 for receiving outer core 102 to be molded around inner core 104, and a third hole 306 for receiving wire coating 112 around outer core 102.

[0026] Figure 1C An embodiment of a thermal sensor wire 120 is shown in which the cross-section is rectangular rather than circular or annular. Thus, the inner core 126 can be rectangular, while the outer core 124 is a rectangular cylinder surrounded by the wire coating 122. Depending on the application, a thermal sensor wire 120 having a rectangular, flat, or elongated cross-section may be more suitable than a circular cross-section.

[0027] Figure 1DAn embodiment of a thermal sensor wire 130 is shown. The thermal sensor wire 130 has a circular or annular cross-section and an outer wire coating 131 disposed around a carrier portion 132. In this embodiment, multiple inner wires are disposed within the carrier portion 132. These wires are shown as a first inner wire 134, a second inner wire 136, and a third inner wire 138. In various embodiments, these inner wires may have different thermal properties. For example, the first inner wire 134 may be formed from a first thermal sensing material 142 having a first transition temperature characteristic, the second inner wire 136 may be formed from a second thermal sensing material 146 having a second transition temperature characteristic, and the third inner wire 138 may be formed from a third thermal sensing material 150 having a third transition temperature characteristic. These transition temperatures may differ. Therefore, the thermal sensor wire 130 may be suitable for use when temperature sensing is useful for protected devices at a variety of different temperatures. For example, the first transition temperature may be 60°C, the second transition temperature may be 70°C, and the third transition temperature may be 80°C. Each internal conductor can be individually coupled to a circuit system or device to indicate when a given temperature has been reached. In the case of battery protection, when the temperature at a given location on the battery exceeds 60°C, the resistance of the first internal conductor 134 changes dramatically, triggering a first warning signal to be sent. When the temperature exceeds 70°C, the second internal conductor 136 can trigger a second signal, such as a higher-level alarm. When the temperature exceeds 80°C, the third internal conductor 138 can trigger a procedure such as power disconnection.

[0028] Although Figure 1D An embodiment with three inner conductors is shown. In other embodiments, fewer or more inner conductors may be used to form multiple temperature sensor conductors. It is worth noting that, to facilitate assembly and wiring, the inner coatings 140, 144, and 148 of the corresponding inner conductors may be different, such as in different colors.

[0029] Figure 1E An embodiment of a thermal sensor wire 160 is shown having a planar, elongated, or rectangular cross-section and an outer wire coating 162 disposed around a carrier portion 161. Figure 1D, a plurality of inner conductors are disposed within the carrier portion 161. These conductors are shown as a first inner conductor 164, a second inner conductor 166, and a third inner conductor 168. In various embodiments, these inner conductors may have different thermal properties. For example, the first inner conductor 164 may be formed from a first thermal sensing material 172 (surrounded by an inner coating 170) having a first transition temperature characteristic, the second inner conductor 166 may be formed from a second thermal sensing material 176 (surrounded by an inner coating 174) having a second transition temperature characteristic, and the third inner conductor 168 may be formed from a third thermal sensing material 180 (surrounded by an inner coating 170) having a third transition temperature characteristic. These transition temperatures may differ. Therefore, like the thermal sensor conductor 130 described above, the thermal sensor conductor 160 may be suitable for use when temperature sensing is useful for a protected device at a variety of different temperatures.

[0030] Figure 4 A thermal sensor wire 400 according to a further embodiment of the present disclosure is depicted. The thermal sensor wire 400 includes an inner core 402, an outer core 404 disposed around the inner core 402, and a wire coating 406 disposed around the outer core 404. As shown, the inner core 402 can be segmented, comprising a first core segment 402A and a second core segment 402B disposed longitudinally relative to one another along the wire axis (z-axis). The first core segment 402A includes a thermal sensing material having a transition temperature when the conductivity within a target temperature range changes by at least an order of magnitude. Thus, for example, the first core segment 402A can include a PPTC material or an NTC material. In contrast, the second core segment 402B does not exhibit a transition temperature within the target temperature range. For example, if the thermal sensor wire 400 is designed to detect overtemperatures above approximately 80°C, the material of the first core segment 402A can be designed to have a transition temperature within a range between approximately 70°C and 80°C.

[0031] Generally, the inner core 402 (including the second core segment 402B) is conductive, so the total resistance and resistance change of the inner core 402 can be easily measured when the first core segment 402A is transformed at 80°C. In various embodiments, the first core segment 402A can be repeated multiple times along the inner core 402, such as Figure 4As shown. For example, the thermal sensor wire 400 can be used in a battery pack, wherein a plurality of first core segments 402A are used on the surface of the battery area to monitor the temperature. In addition, the second core segment 402B can include a simple conductor that does not exhibit a transition temperature, such as carbon black, wherein the conductivity varies by an order of magnitude or more within a few degrees (at least not within the target temperature range to be monitored). Therefore, the second core segment 402B can be arranged next to an area where no temperature is to be monitored, such as a gap between batteries, an edge, etc. In this way, the PPTC material or NTC material does not need to be provided throughout the inner core 402, but only needs to be provided in a selected segment, which can be selectively arranged near the device area to be monitored.

[0032] like Figure 4 As further shown, the wire coating 406 includes a first coating segment 406A disposed around the first core segment 402A and a second coating segment 406B disposed around the second core segment 402B. The first coating segment 406A has a first color, and the second core segment 406B has a second color different from the first color. In this manner, the thermal sensor wire 400 can indicate the location of the thermal sensing portion (first core segment 402A) along its length, facilitating appropriate application of the thermal sensing portion of the thermal sensor wire 400 to various portions of the device to be monitored or protected.

[0033] According to various embodiments, the thermal sensor wire can be formed using any suitable technique, including single-wire extrusion of PTC material, where the cross-section is controlled by various dies (ranging from circular to rectangular); multi-layer coextrusion to create multi-layer wire configurations with varying functional properties, where some layers are conductive and others are non-conductive; extrusion along the length of the wire to provide a variable cross-section; lamination / calendering of multiple "wires" into segments with periodically varying lengths along the length of the thermal sensor wire, in roll-to-roll or batch processing; hot melt pressing or printing followed by lamination. In some embodiments, the core portion forming the thermal sensing portion of the thermal sensor wire can be extruded with a constant diameter. In some embodiments, the core portion can be extruded to produce a variable diameter within the core portion. For example, the overall resistance of the wire can be maintained at an acceptable level by maintaining a first diameter of the core portion over a certain length of wire, while at some point the diameter can be changed to a second, smaller diameter. For example, the diameter of the (conductive) core portion can be determined to have a first value along a wire segment where thermal sensing is not performed, and a second value along each segment where thermal sensing is performed.

[0034] Now go to Figure 5 , an exemplary process flow 500 is shown. At block 502, a carrier portion of a thermal sensor wire is formed. The carrier portion may extend along a long axis of the thermal sensor wire.

[0035] At block 504, the thermal sensing material is formed into a thermal sensing portion of the thermal sensor wire, wherein the thermal sensing portion extends along the length of the thermal sensor wire and is adjacent to the carrier portion. In some embodiments, the thermal sensing portion may be formed as a core and disposed within the carrier portion, while in other embodiments, the carrier portion may be formed as a core within the thermal sensing portion.

[0036] In various embodiments, the thermal sensing material may include a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material. Within a target temperature range, the thermal sensing material may exhibit a thermal transition characteristic. For example, the thermal transition may involve an increase or decrease in resistance by one, two, or four orders of magnitude within a narrow temperature range, such as within a few degrees Celsius. The target range for the thermal transition may be set depending on the application, but according to various non-limiting embodiments, the target range for the thermal transition may generally be within a range of -50°C to 200°C. In contrast, the carrier portion may be formed of a carrier material that exhibits no thermal transition within the target temperature range, meaning that the resistance does not change abruptly, such as by a factor of 10 (one order of magnitude) or more within a narrow temperature range, such as by a few degrees Celsius within the target temperature range. Therefore, due to the thermal transition of the thermal sensing material within the target temperature range, the thermal sensor wire may experience a dramatic change in resistance.

[0037] In some embodiments, the thermal sensing portion can be formed as a plurality of different inner conductors, each of which includes a thermal sensing material having a given transition temperature. For example, three different thermal sensing materials having three different transition temperatures can be used to form three different inner conductors. To facilitate identification, the three different inner conductors can be coated with different corresponding coatings and can be disposed within a common carrier portion that includes the thermal sensing conductors and a common coating disposed around the carrier portion.

[0038] At block 506, a coating is formed around the thermal sensing portion and the carrier portion. In various embodiments, the coating may be an electrical insulator as in known wire coatings.

[0039] In some embodiments, the thermal sensing portion can be formed as a plurality of different inner conductors, each of which includes a thermal sensing material having a given transition temperature. For example, three different thermal sensing materials having three different transition temperatures can be used to form three different inner conductors. To facilitate identification, the three different inner conductors can be coated with different coatings, and the three different inner conductors can be disposed within a common carrier portion of the thermal sensing conductor, which includes a common coating disposed around the carrier portion.

[0040] In summary, this embodiment can be used for overcurrent and / or overtemperature protection similar to standard PPTC devices. In various embodiments, thermal sensor wires can be arranged as sensing elements (as a continuous PPTC structure) or in series and / or parallel electrical configurations for multiple temperature sensing zones. Digital components can be placed in series, where the resistance / impedance is low during normal operation, and where the resistance / impedance is high during abnormal conditions, allowing the use of a simple digital signal that can be detected by a microprocessor or driving an electrical switch such as a relay or field-effect transistor.

[0041] Although the present embodiment has been disclosed with reference to certain embodiments, the above-described embodiments may be modified, altered, and varied in many ways without departing from the scope and spirit of the present disclosure, as defined in the appended claims. Accordingly, the present embodiment is not limited to the above-described embodiments, but may have the full scope defined by the language of the following claims and their equivalents.

Claims

1. A thermal sensor wire, comprising: a heat sensing portion extending along the wire axis of the heat sensor wire; as well as a carrier portion extending along the wire axis and adjacent to the thermal sensing portion, wherein the thermal sensing portion comprises a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material; The heat sensing portion includes an inner core, the carrier portion is arranged circumferentially around the inner core, and further includes: a wire coating disposed around the carrier portion, and The inner core includes a first core segment and a second core segment, and the first core segment and the second core segment are longitudinally arranged with respect to each other along the wire axis, wherein the first core segment includes a transition temperature in which the electrical conductivity changes by at least one order of magnitude within the target temperature range, and wherein the second core segment does not have a transition temperature within the target temperature range. 2 . The thermal sensor wire according to claim 1 , comprising a circular cross-section or a rectangular cross-section.

3. A thermal sensor wire according to claim 1, comprising a plurality of layers with different functional properties, wherein: The thermal sensing portion includes a first layer having electrical conductivity, wherein the second layer is an electrical insulating layer. 4 . The thermal sensor wire according to claim 1 , wherein the thermal sensing portion comprises a variable cross-section along the length of the thermal sensor wire.

5. The thermal sensor wire according to claim 1, wherein: The wire coating includes a first coating segment disposed around the first core segment and a second coating segment disposed around the second core segment, wherein the first coating segment has a first color and the second core segment has a second color different from the first color.

6. The thermal sensor wire according to claim 1, further comprising: an outer conductor coating disposed around the carrier portion; as well as a plurality of inner conductors disposed within the carrier portion, The heat sensing portion is provided in a first inner conductor of the plurality of inner conductors and includes a first heat sensing material having a first transition temperature. The plurality of inner conductive wires include at least one additional conductive wire comprising a second thermal sensing material, and the second thermal sensing material has a second transition temperature different from the first transition temperature.

7. The thermal sensor wire according to claim 1, comprising a plurality of laminated / calendered sections formed by a plurality of wires, and having periodically different length sections along the length direction of the thermal sensor wire.

8. A method for forming a thermal sensor wire, comprising: forming a carrier portion of the thermal sensor wire, wherein the carrier portion extends along the length of the thermal sensor wire; as well as forming the thermal sensing material into a thermal sensing portion of the thermal sensor wire, wherein the thermal sensing portion extends along the length of the thermal sensor wire and is adjacent to the carrier portion; The thermal sensing material comprises a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material, characterized in that a thermal transition occurs within a target temperature range, and the carrier portion comprises a carrier material that has no thermal transition within the target temperature range. The method further comprises: a step of forming a thermal sensing material as the inner core portion of the thermal sensor wire; and the step of forming a carrier portion around the core portion, and The step of forming the thermal sensing material into a core further comprises: extruding the thermal sensing material to form a first core segment of the core; and After extruding the thermal sensing material, extruding a second material to form a second core segment of the core, wherein the first core segment includes a transition temperature where the electrical conductivity varies by at least one order of magnitude within a target temperature range, and wherein the second core segment does not exhibit a transition temperature within the target temperature range.

9. A method for forming a thermal sensor wire according to claim 8, comprising the step of extruding the inner core portion into a constant diameter.

10. A method of forming a thermal sensor wire according to claim 8, comprising the step of extruding the inner core portion to produce a variable diameter in the inner core portion.

11. A method of forming a thermal sensor wire according to claim 8, comprising the step of forming the thermal sensing material and the carrier portion as a series of layers in a multi-layer wire configuration.

12. The method for forming a thermal sensor wire according to claim 8, further comprising: The step of forming a coating around the carrier portion, wherein the step of forming the coating further comprises: the step of forming a first coating segment around the first core segment, and The step of forming a second coating segment around the second core segment, wherein the first coating segment has a first color and the second core segment has a second color different from the first color.

13. A thermal sensor wire forming method according to claim 8, wherein: The thermal sensing material includes a first thermal sensing material and a second thermal sensing material, wherein the first thermal sensing material and the second thermal sensing material are extruded into a first conductive wire and a second conductive wire and arranged in a carrier material, wherein the first thermal sensing material includes a first transition temperature, and the second thermal sensing material includes a second transition temperature different from the first transition temperature.

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