US20040056753A1 - Sensor - Google Patents

Sensor Download PDF

Info

Publication number
US20040056753A1
US20040056753A1 US10/624,789 US62478903A US2004056753A1 US 20040056753 A1 US20040056753 A1 US 20040056753A1 US 62478903 A US62478903 A US 62478903A US 2004056753 A1 US2004056753 A1 US 2004056753A1
Authority
US
United States
Prior art keywords
sensor
sensing elements
laminar
surface
resistance
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.)
Abandoned
Application number
US10/624,789
Inventor
Justin Chiang
James Toth
William Beadling
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.)
Littelfuse Inc
Original Assignee
Chiang Justin N.
James Toth
Beadling William C.
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
Priority to US09/182,590 priority Critical patent/US6137669A/en
Priority to US09/830,547 priority patent/US6597276B1/en
Application filed by Chiang Justin N., James Toth, Beadling William C. filed Critical Chiang Justin N.
Priority to US10/624,789 priority patent/US20040056753A1/en
Publication of US20040056753A1 publication Critical patent/US20040056753A1/en
Assigned to LITTELFUSE, INC. reassignment LITTELFUSE, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TYCO ELECTRONICS CORPORATION
Application status is Abandoned legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01KMEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply, e.g. by thermoelectric elements
    • G01K7/16Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply, e.g. by thermoelectric elements using resistive elements
    • G01K7/22Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply, e.g. by thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01KMEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K3/00Thermometers giving results other than momentary value of temperature
    • G01K3/08Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values
    • G01K3/14Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values in respect of space
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01CRESISTORS
    • H01C7/00Non-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
    • H01C7/02Non-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
    • H01C7/027Non-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
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01KMEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K3/00Thermometers giving results other than momentary value of temperature
    • G01K3/08Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values
    • G01K3/14Thermometers giving results other than momentary value of temperature giving differences of values; giving differentiated values in respect of space
    • G01K2003/145Hotspot localization

Abstract

A laminar sensor (1) for detecting changes on a laminar substrate (35). The sensor includes a laminar sheet (3) which has a first surface (5) and a second opposite surface (7), and is made from a conductive polymer composition which exhibits temperature dependent resistance behavior, preferably PTC behavior. A plurality of sensing elements (12) are electrically connected, preferably in series, on the sensor. Each sensing element is formed as an electrode pair containing a first electrode and a second electrode. The first and second electrodes (9,11) may be on the same surface of the laminar sheet or on opposite surfaces of the sheet. Two electrical leads (17,19) are present for connecting the sensing elements into a circuit, which may be used to detect changes in resistance which occur when a sensing element is exposed to an elevated temperature, a change in pressure, or a solvent.

Description

    BACKGROUND OF THE INVENTION
  • 1. Field of the Invention [0001]
  • This invention relates to sensors, including temperature sensors. [0002]
  • 2. Introduction to the Invention [0003]
  • A wide variety of electronic components and other articles are subject to damage if exposed to elevated temperature. It is, therefore, often important to be able to determine if a component has been subjected to such temperature. Various detection techniques, e.g. thermochromic materials which change color when exposed to a specific temperature, have been proposed for this purpose. Such techniques suffer from the requirement that the article must be visible in order to detect the color change, and thus are ineffective when the article is enclosed. Various electronic detectors, designed to identify an electrical change resulting from a high temperature, have also been proposed. Such detectors may not be able to determine whether a particular part of an article has been exposed to a high temperature, relying instead on the average over the entire surface. In addition, sensors which are able to maintain direct contact with the substrate, even when the substrate is not flat, are desirable. Such sensors would have sufficient flexibility that they could provide two-dimensional sensing over a large surface, and be able to be bent over an edge to provide three-dimensional sensing. [0004]
  • Conductive polymer compositions exhibiting a positive temperature coefficient of resistance (PTC) effect are well known. Such compositions comprise a polymeric component, and dispersed therein, a particulate conductive filler. At low temperatures the composition has a relatively low resistivity. However, when the composition is exposed to a high temperature, due for example, to a high current condition, the resistivity of the composition increases, or “switches”, often by several orders of magnitude. The temperature at which this transition from low resistivity to high resistivity occurs in a PTC composition is the switching temperature, T[0005] s. Ts is defined as the temperature at the intersection point of extensions of the substantially straight portions of a plot of the log of the resistance of an element prepared from the composition as a function of temperature which lie on either side of the portion of the curve showing a sharp change in slope. Similarly, a composition exhibiting a negative temperature coefficient (NTC) of resistance will have a switching temperature, Ts, in the region at which the resistivity goes from a high to a low value.
  • The use of a sensor comprising a PTC conductive polymer to detect an overtemperature condition is known. For example, Japanese Patent Application No. 10-95019, filed Apr. 7, 1998 (K. K. Raychem), the disclosure of which is incorporated herein by reference, discloses a elongate temperature sensor which can be used to detect overheating in a battery. Batteries which overheat are subject to damage, and in addition may damage the packaging surrounding them and the components in contact with them. While overheating may be due to external environmental conditions, for secondary, i.e. rechargeable batteries, such overheating may occur as a result of excessive charging. The overheating may result in damage to the internal components of the battery, the generation of gas, and, under extreme conditions, explosion of the battery. For example, for nickel-metal hydride batteries, it is desirable to keep the temperature below 100° C. to avoid the evolution of hydrogen. It is, therefore, important to identify batteries which have been subject to overheating before damage can occur. In Japanese Patent Application No. 10-95019, a sensor is attached to a plurality of batteries. An elongate tape composed of a PTC conductive polymer comprising spaced-apart sensing components and connecting components is in contact with the individual battery cells. The sensing components are electrically connected in series so that the resistance of the sensor is the sum of the resistances of each individual sensing component. The sensor is positioned so that a sensing component is in contact with the external surface of a battery cell, and preferably each individual battery cell contacts a different sensing component. When the battery cells are in a normal, low temperature condition, the resistance of the sensor is low. If, however, one battery cell heats to a temperature above T[0006] s, the resistance of the sensing component in contact with that battery cell increases, thus increasing the total resistance of the sensor and indicating that at least one battery has been subject to overheating.
  • BRIEF SUMMARY OF THE INVENTION
  • The approach taken in Japanese Patent Application No. 10-95019 requires that the entire battery cell heat to a temperature sufficient to cause the PTC conductive polymer composition to switch. This means that if there is a relatively small hot spot inside the battery cell, which is sufficient to cause damage to a small region of the battery but is insufficient to heat the entire cell, it will not be detected. Many batteries, such as lithium ion polymer batteries have a layered sheet construction in which an anode and a cathode are separated by a separator, and in addition comprise an electrolyte. In practice, the layered sheet is rolled into a cylinder and positioned inside a can to form a battery cell. A hot spot in the center of the cylinder, due, for example, to inhomogeneities in the anode, cathode, or separator, can cause damage to the electrolyte, which is solvent-based. It is, therefore, desirable to have a sensor which can detect not just the temperature of the entire battery cell, but rather the temperature of individual spots within the battery cell. [0007]
  • In another application, a lithium ion polymer battery, used unrolled in its thin, flat configuration, can be positioned behind the screen of a laptop computer to detect temperature changes. For this application, it is necessary to have an array of sensing elements as a point sensor applied to one part of the screen may not reflect a change elsewhere on the screen. [0008]
  • Detecting individual spots on a substrate is also important for articles other than batteries. It is desirable to have a sensor in which the pattern of the sensing elements can be designed for a specific configuration, so that individual components, e.g. individual elements on a printed circuit board, can be in contact with the sensor. Such a sensor can be used for situations in which the temperature at one spot is not representative of the entire surface, but for which sensing is still required. Furthermore, it is desirable to have a sensor which can be used to detect hot spots over two dimensions and over a large area. We have now found that a laminar sensor comprising a laminar sheet comprising a conductive polymer composition and a plurality of sensing elements has sufficient flexibility to contact substrates of nonuniform or irregular structure, as well as the ability to detect temperature changes over a broad area. In addition, the sensor can be used to detect resistance changes resulting from pressure or exposure to solvents. Thus, in a first aspect this invention provides a laminar sensor for detecting changes, e.g. temperature changes, on a laminar substrate, the sensor having a resistance at 20° C. R[0009] T and comprising
  • (1) a laminar sheet which (a) has a first surface and a second opposite surface, and (b) comprises a conductive polymer composition which (i) exhibits temperature dependent resistance behavior and (ii) has a switching temperature T[0010] s;
  • (2) a plurality of sensing elements and (a) each of which comprises an electrode pair, said electrode pair comprising a first electrode and a second electrode, said electrodes being separated from each other and in contact with the laminar sheet, and (b) which are electrically connected in a resistive network, at least some of said sensing elements connected in series; and [0011]
  • (3) two electrical leads for connecting the sensing elements into a circuit. [0012]
  • In a second aspect, the invention provides a lithium ion polymer battery which comprises [0013]
  • (A) a laminar battery element surrounded by an insulating material, said battery element comprising (1) first and second battery electrodes, (2) an anode, (3) a separator, (4) a cathode, and (5) and electrolyte; and [0014]
  • (B) a laminar temperature sensor of the first aspect of the invention positioned in direct contact with the insulating material and covering at least 75% of one laminar surface of the insulating material. [0015]
  • In a third aspect, the invention provides an electrical circuit which comprises [0016]
  • (A) a laminar sensor of the first aspect of the invention; and [0017]
  • (B) detection equipment electrically connected to the electrical leads to detect a change in the sensor.[0018]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • The invention is illustrated by the drawings in which FIG. 1 is a top schematic view of a sensor of the invention; [0019]
  • FIG. 2 is a cross-sectional view along line [0020] 2-2 of FIG. 1;
  • FIGS. 3 and 4 are top schematic views of sensors of the invention; [0021]
  • FIG. 5 is an electrical circuit containing a sensor of the invention; [0022]
  • FIGS. 6 and 7 are top schematic views of other sensors of the invention; and [0023]
  • FIG. 8 is a cross-sectional view of another sensor of the invention. [0024]
  • DETAILED DESCRIPTION OF THE INVENTION
  • The sensor of the invention comprises a laminar sheet comprising a conductive polymer composition which exhibits temperature dependent resistance behavior. The composition preferably exhibits PTC behavior, but in some applications, it is preferred that a composition exhibiting NTC behavior, i.e. a change from high to low resistivity with increasing temperature, be used. The conductive polymer composition comprises a polymeric component, and dispersed therein, a particulate conductive filler. The polymeric component comprises one or more polymers, one of which is preferably a crystalline polymer having a crystallinity of at least 10% as measured in its unfilled state by a differential scanning calorimeter. Suitable crystalline polymers include polymers of one or more olefins, particularly polyethylene such as high density polyethylene; copolymers of at least one olefin and at least one monomer copolymerisable therewith such as ethylene/acrylic acid, ethylene/ethyl acrylate, ethylene/vinyl acetate, and ethylene/butyl acrylate copolymers; melt-shapeable fluoropolymers such as polyvinylidene fluoride (PVDF) and ethylene/tetrafluoroethylene copolymers (ETFE, including terpolymers); and blends of two or more such polymers. For some applications it may be desirable to blend one crystalline polymer with another polymer, e.g. an elastomer or an amorphous thermoplastic polymer, in order to achieve specific physical or thermal properties, e.g. flexibility or maximum exposure temperature. The polymeric component generally comprises 40 to 90% by volume, preferably 45 to 80% by volume, especially 50 to 75% by volume of the total volume of the composition. [0025]
  • The particulate conductive filler which is dispersed in the polymeric component may be any suitable material, including carbon black, graphite, metal, metal oxide, conductive coated glass or ceramic beads, particulate conductive polymer, or a combination of these. The filler may be in the form of powder, beads, flakes, fibers, or any other suitable shape. The quantity of conductive filler needed is based on the required resistivity of the composition and the resistivity of the conductive filler itself. For many compositions the conductive filler comprises 10 to 60% by volume, preferably 20 to 55% by volume, especially 25 to 50% by volume of the total volume of the composition. [0026]
  • The conductive polymer composition may comprise additional components, such as antioxidants, inert fillers, nonconductive fillers, radiation crosslinking agents (often referred to as prorads or crosslinking enhancers, e.g. triallyl isocyanurate), stabilizers, dispersing agents, coupling agents, acid scavengers (e.g. CaCO[0027] 3), or other components. These components generally comprise at most 20% by volume of the total composition.
  • The composition used in the laminar sheet preferably exhibits positive temperature coefficient (PTC) behavior, i.e. it shows a sharp increase in resistivity with temperature over a relatively small temperature range. In this application, the term “PTC” is used to mean a composition which has an R[0028] 14 value of at least 2.5 and/or an R100 value of at least 10, and it is preferred that the composition should have an R30 value of at least 6, where R14 is the ratio of the resistivities at the end and the beginning of a 14° C. range, R100 is the ratio of the resistivities at the end and the beginning of a 100° C. range, and R30 is the ratio of the resistivities at the end and the beginning of a 30° C. range. Generally the compositions used in devices of the invention show increases in resistivity which are much greater than those minimum values. It is preferred that these compositions have a PTC anomaly at at least one temperature over the range from 20° C. to (Tn+5° C.) of at least 101, preferably at least 102, particularly at least 103, especially at least 104, i.e. the log[resistance at (Tn+5° C.)/resistance at 20° C.] is at least 1.0, preferably at least 2.0, particularly at least 3.0, especially at least 4.0, where Tm is the melting temperature of the polymeric component as measured at the peak of the endotherm of a differential scanning calorimeter (DSC) trace. (When there is more than one peak, as for example in a mixture of polymers, Tm is defined as the temperature of the highest temperature peak.)
  • Suitable conductive polymer compositions exhibiting PTC behavior are disclosed in U.S. Pat. Nos. 4,237,441 (van Konynenburg et al), 4,545,926 (Fouts et al), 4,724,417 (Au et al), 4,774,024 (Deep et al), 4,935,156 (van Konynenburg et al), 5,049,850 (Evans et al), 5,250,228 (Baigrie et al), 5,378,407 (Chandler et al), 5,451,919 (Chu et al), 5,582,770 (Chu et al), 5,701,285 (Chandler et al), and 5,747,147 (Wartenberg et al), and in copending, commonly assigned U.S. application Ser. No. 08/798,887 (Toth et al, filed Feb. 10, 1997), the counterpart of which is published as International Patent Publication No. WO97/29711, published Sep. 26, 1996. The disclosure of each of these patents and applications is incorporated herein by reference. [0029]
  • The laminar sheet has a first surface and a second opposite surface. The sheet can be of any thickness, but for many applications in which it is desirable that the sensor be flexible, it is preferred that the sheet be relatively thin, i.e. have a thickness of at most 1.0 mm (0.040 inch), preferably at most 0.76 mm (0.030 inch), particularly at most 0.51 mm (0.020 inch, e.g. 0.08 to 0.25 mm (0.003 to 0.010 inch). The sheet is preferably a solid layer, but it may contain slits or openings in order to accommodate attachment means to the substrate or to enhance the flexibility or fit onto a substrate. The sheet may be crosslinked, e.g. by irradiation or chemical means. The sheet may comprise a single conductive polymer, or different conductive polymer compositions may be used in different sections of the sheet to provide different thermal or electrical capabilities. [0030]
  • A plurality of sensing elements is attached to the laminar sheet. Each sensing element in the preferred embodiment comprises an electrode pair in which a first electrode is attached to the first surface of the sheet and a second electrode is attached to the second surface of the sheet. In this embodiment, a current flow would be through the thickness of the sheet. The electrodes comprise an electrically conductive material, e.g. a metal foil, a conductive ink, or a metal layer which has been applied by plating or other means. The attachment of the electrodes to the surface of the sheet may be either direct, e.g. a metal foil or conductive ink in direct physical contact with the sheet, or indirect, e.g. a metal layer applied via an adhesive or tie layer. In another embodiment, the first and second electrodes can be positioned on the first surface, so that any current flow is parallel to the first surface. The first and second electrodes are generally physically (i.e. spatially) separated from one another. [0031]
  • The sensing elements are electrically connected in a resistive network, and at least some of the sensing elements in the resistive network are electrically connected in series. Preferably a first connecting component connects two first electrodes, while a second connecting component connects two second electrodes. In an embodiment in which the first and second electrodes are on opposite surfaces of the sheet, the second connecting component is positioned between, and on the opposite surface of, two first electrodes so that one of the two second electrodes to which it is connected overlaps one of the two first electrodes. In some embodiments, the sensor may comprise a number, i.e. at least two, groups of sensing elements in an array. In the array, each of the sensing elements within each group is connected in series, but each group is not electrically connected to some or all of the other groups. The group may be in the form of a line or any other pattern, and groups may be arranged in the array, e.g. in the form of a grid, and may be connected in parallel. Each group comprises at least two sensing elements, but generally there are more. This design is particularly useful when the sensor is intended to have different densities of sensing elements in different sections, e.g. when particular sections of a substrate have a greater tendency to overheat than others and greater precision is desired in some sections. Furthermore, this design allows the sensor to be used in a multiplexing mode. In this process, the resistance of different groups, e.g. lines, of sensing elements is scanned, e.g. line by line in both an x and a y direction, and the resistance values of each scan are compared to a previous scan. A mathematical algorithm can be used to identify a hot spot and its location. [0032]
  • The resistive network may also comprise other circuit elements, e.g. components such as capacitors, diodes, switches, and fixed resistors. Such components may be used to “tune” the electrical response to achieve certain conditions such as maximum sensitivity, spatial accuracy, optimal time response, and the lowest power consumption. [0033]
  • For a sensor in which there is only one line or group of sensing elements it is preferred that the total surface area of the first electrodes is at least 10%, preferably at least 20% of the total surface area of the first surface, and is at most 80%, preferably at most 70%, of the total surface area of the first surface. [0034]
  • Also present are two electrical leads suitable for connecting the sensing elements into a circuit. The circuit may comprise sensing equipment for detecting a resistance change, or it may comprise conventional components, e.g. a power source or load resistance. These leads may be in the form of metal pads on the sheet, similar in material to the electrodes, or they may be wires or other conductive elements. [0035]
  • It is preferred that the first and second electrodes and the first and second connecting components be the same material. Particularly preferred for electrodes and connecting components are electrodeposited metal foils such as nickel, copper, or nickel-copper foils, which may be laminated to the sheet. A conventional photolithographic process can be used to remove metal from some or all of the regions not intended to be electrodes, connecting components, or electrical leads. Some metal may be retained in various sections of the sensor for thermal dissipation or as a reinforcing element. Such metal is not electrically connected to the sensing elements. In an alternative process, the electrodes and connecting components can be applied by screen-printing. [0036]
  • The shape of individual sensing elements may be the same or different on the sensor, although it is preferred that the shape of the first and second electrodes in an individual sensing element be the same. Depending on their shapes, the sensing elements may have the same or different resistance, R[0037] S, at 20° C. It is important that the sensing elements be sufficiently low in resistance (e.g. sufficiently large) so that the total series resistance at 20° C. of the circuit RT is low enough that if one sensing element trips and goes into the high resistance state, the total resistance of the sensor will reflect this change with sufficient resolution. The amount of resistance change required to indicate an overheating condition, pressure change, or exposure to solvents is a function of the type of sensing equipment used. In the preferred embodiment in which the majority of the sensing elements or all of the sensing elements are in series, it is preferred that when at least one sensing element is exposed to a temperature greater than Ts, the resistance of the sensor is at least 1.1RT, preferably at least 1.3RT, particularly at least 1.5RT. Because the sensitivity of the sensor is a function of the number and resistance of the sensing elements, and because larger increases in resistance will mean that the total change in resistance of the sensor when a sensing element trips is larger, compositions with higher PTC anomalies generally are preferred. For example, in a sensor with 100 sensing elements, each with a resistance of 1 ohm, RT will be 100 ohms. If one sensing element increases in resistance by one decade, i.e. to 10 ohms, the sensor resistance will be 109 ohms, i.e. 1.09RT. If the one sensing element increases in resistance by two decades, i.e. to 100 ohms, the sensor resistance will be 199 ohms, i.e. 1.99RT. A three decade resistance change in one sensing element, to 1000 ohms, will give a sensor resistance of 1099 ohms, i.e. 11RT.
  • Sensors of the invention can be used to detect temperature changes on any type of substrate, but are particularly useful for detecting changes on a laminar substrate, such as a battery, a hot plate, a heating pad, an electric motor case, or a printed circuit board. Due to its laminar structure and its flexibility, the sensor can be in direct physical contact with the substrate. Although the sensor may cover only a part of the substrate, it is particularly useful when the sensor covers a substantial part of the substrate, i.e. at least 50%, preferably at least 60%, particularly at least 75% of one surface of the substrate. [0038]
  • Although the sensor of the invention is primarily intended to serve as a passive component on a substrate, under certain circumstances, if the resistance of the sensor is sufficiently low, it may be possible to pass current through the sensor and use it both to detect temperature changes and to act as an overcurrent protection device. For this application, the sensor is connected in series in a circuit with a power source and other electrical components which provide a load resistance, and sensing equipment is connected to the sensor in a separate sensing circuit. For this application, it is preferred that the sensing elements be relatively large in size so that the sensor resistance is low. The actual size of the sensing elements will be a function of the maximum circuit resistance which is often dictated by the maximum voltage drop in the system, and the required hold current, i.e. the maximum amount of current the device can pass without tripping, for the circuit. [0039]
  • It is generally preferred that the resistance of the sensor be as low as possible. This is particularly desirable when the sensor is actually part of a circuit and is simultaneously acting as an overcurrent protection device and a temperature sensing device. Under these circumstances, it is important that the resistance of the sensor be low with respect to the circuit to be measured. Thus the resistivity at 20° C. of the composition in the laminar sheet is preferably low, i.e. less than 100 ohm-cm, preferably less than 20 ohm-cm, particularly less than 10 ohm-cm, especially less than 5 ohm-cm. [0040]
  • The sensor of the invention is particularly useful when the substrate is a laminar battery element, in particular a lithium ion polymer battery element. The sensor is sufficiently flexible that it can be rolled into a cylinder, as is commonly done with a lithium ion polymer battery element, and then can detect temperature or other changes which occur at various spots on the battery element and which result in a change in resistance. [0041]
  • Although the sensor of the invention is suitable for use in detecting a change in resistance, it also can be used to detect a rate of change of resistance. [0042]
  • In other applications, sensors of the invention can be used to detect changes in pressure, as the resistance of the sensing elements will change with pressure. Sensors of the invention can also be used to detect the presence of solvents if the conductive polymer composition is selected to swell (and thus change resistance) when exposed to a solvent. [0043]
  • The invention is illustrated by the drawings in which FIG. 1 is a top schematic view of a sensor of the invention and FIG. 2 is a cross-sectional view along line [0044] 2-2 of FIG. 1. Sensor 1 has a laminar sheet 3 composed of a conductive polymer composition and having first and second surfaces 5,7. Attached to first surface 5 are first electrodes 9. Two fit electrodes 9 are electrically connected by connecting component 13. Attached to second surface 7 are second electrodes 11. Two second electrodes 11 are electrically connected by connecting component 15. Sensing element 12 is composed of an electrode pair of one first electrode 9 and the one second electrode 11 which is opposite it. First and second electrical leads 17,19 are positioned on first surface 5 and provide means for connection to detection electronics or a power source. Because all of the sensing elements are connected in series, only one pair of electrical leads 17,19 is required to measure the resistance of the entire sensor.
  • FIGS. 3 and 4 are top schematic views of the sensors described below in Examples 1 and 2, respectively. [0045]
  • FIG. 5 shows an electrical circuit used in Example 2. In this circuit sensor [0046] 1 is electrically in series with power source 21 and load resistor 23. Detection electronics 25, capable of detecting changes in resistance of the sensor, are connected to sensor 1 in a separate sensing circuit.
  • FIG. 6 shows a top schematic view of another sensor of the invention, in which multiple sensor lines [0047] 29 are present. Each line has first and second electrical leads 17,19, so that individual measurements of that line can be made and some determination of the location of the hot spot or site of the detected change can be made.
  • FIG. 7 shows a top schematic view of another sensor of the invention, in which multiple sensor lines are present and the sensing elements are matrixed to provide increased accuracy for determination of the hot spot or site of the detected change. Third and fourth electrical leads [0048] 31,33 are present to allow additional resistance measurements to be made, e.g. for a multiplexing application.
  • FIG. 8 shows in cross-section a sensor [0049] 1 of the invention positioned on substrate 35, e.g. a battery. First and second electrodes 9,11 are attached to the same surface, first surface 5, of laminar sheet 3. Second electrode 11 is electrically connected in series to another first electrode 9 by means of connecting component 13. Sensing element 12 is composed of first electrode 9 and its adjacent second electrode 11, separated by the conductive polymer in laminar sheet 3.
  • The invention is illustrated by the following examples. [0050]
  • EXAMPLE 1
  • A conductive polymer composition comprising a mixture of 40% by weight ethylene/n-butyl acrylate copolymer (Enathene™ 705-009, having a melting temperature of about 105° C. and a density of about 0.922 g/cc, available from Quantum Chemical), 10% by weight high density polyethylene (Petrothene™ LB832, having a melting temperature of about 135° C. and a density of about 0.954 g/cc, available from Quantum Chemical), and 50% by weight carbon black (Raven 430, having a density of 1.8, available from Columbian Chemicals) was mixed, formed into a sheet having a thickness of 0.13 mm (0.005 inch), and laminated on either side with electrodeposited nickel-copper foil having a thickness of 0.043 mm (0.0013 inch). The laminate was irradiated to 10 Mrads, and was then subjected to a photolithographic and etching process similar to the type described in U.S. Pat. No. 5,864,281 (Zhang et at), the disclosure of which is incorporated herein by reference. The laminate was cleaned and photo resists were used to produce masks over the metal foils in the regions which were to be the sensing elements and the electrical connection (i.e. connecting components) regions. The remaining regions of the foils were left exposed and were etched to remove the metal foils in those areas. The masks were then removed. The etched laminate was cut into pieces 51×76 mm (2×3 inches), each having the configuration shown in FIG. 3. For this sensor, fifty-two sensing elements, each about 4 mm (0.18 inch) square and having a resistance of about 0.1 ohm, were evenly distributed and electrically connected in series. The sensing elements covered approximately 28% of each laminar surface of the sensor. Metallized regions at the edge of the element were suitable for use as electrical leads. The resistivity of the composition was about 0.5-1.0 ohm-cm; the switching temperature T[0051] s of the composition as defined above, was about 93° C.
  • The resistance of the sensor at 20° C. was 4.1 ohms. A heat gun was used as an external heat source and was applied to various numbers of sensing elements. The temperature of the sensor was monitored using a thermal imaging camera, and the maximum temperature, as well as the resistance of the sensor, were recorded. The results are shown in Table I. [0052]
    TABLE I
    Number of Elements Maximum Temperature
    Heated (° C.) Resistance (ohms)
    0 20 4.1
    1 70 8.0
    2 100 8.8
    ˜20 85 20
    ˜40 100 111
  • EXAMPLE 2
  • Using the procedure and compositions of Example 1, a sensor having the configuration shown in FIG. 4 was prepared. The sensor had dimensions of 51×76 mm (2×3 inches), with six sensing elements, each 10×30 mm (0.4×1.2 inches), connected in series. The sensing elements covered approximately 48% of each laminar surface of the sensor. The resistance of the sensor at 20° C. was 0.042 ohm, each sensor having a resistance of about 0.007 ohm. [0053]
  • The sensor was connected in a circuit (as shown in FIG. 5) in series with a power supply and a load resistor which limited the current passing through the sensor to 5A when a voltage of 18 volts was applied. Under these conditions, the highest temperature detected on the sensor by a thermal imaging camera was 33° C. and the sensor did not trip. A heat gun was used to apply heat to one sensing element, causing the sensing element to increase in resistance and in temperature to at least 95° C. In addition, the thermal derating of the sensor, affected by the increase in temperature of the sensing element, prevented the sensor from continuing to be able to pass 5A and the sensor tripped. The heat gun was removed from the sensing element, leaving the sensor in the tripped state and the sensing element at 95° C. When the power was removed from the sensor, the sensor cooled down and reset. [0054]

Claims (18)

What is claimed is:
1. A laminar sensor for detecting changes on a laminar substrate, the sensor having a resistance at 20° C. RT and comprising
(1) a laminar sheet which (a) has a first surface and a second opposite surface, and (b) comprises a conductive polymer composition which (i) exhibits temperature dependent resistance behavior and (ii) has a switching temperature Ts;
(2) a plurality of sensing elements (a) each of which comprises an electrode pair, said electrode pair comprising a first electrode and a second electrode, said electrodes being separated from each other and in contact with the laminar sheet, and (b) which are electrically connected in a resistive network, at least some of said sensing elements connected in series; and
(3) two electrical leads for connecting the sensing elements into a circuit.
2. A sensor according to claim 1 wherein the first electrode is attached to the first surface and the second electrode is attached to the second surface.
3. A sensor according to claim 1 wherein the first and second electrodes are both attached to the first surface.
4. A sensor according to claim 1 wherein the conductive polymer exhibits PTC behavior.
5. A sensor according to claim 1 wherein the laminar sheet has a thickness of at most 1.0 mm (0.040 inch).
6. A sensor according to claim 1 wherein the conductive polymer composition has a resistivity of at most 10 ohm-cm.
7. A sensor according to claim 1 wherein all of the sensing elements are connected in series.
8. A sensor according to claim 1 wherein when at least one sensing element is exposed to a temperature greater than Ts, the resistance of the sensor is at least 1.1RT, at least 1.3RT.
9. A sensor according to claim 1 wherein the sensor is positioned directly in contact with and covering at least 75% of one surface of the substrate.
10. A sensor according to claim 1 wherein the substrate is a laminar battery element, preferably a lithium ion polymer battery element.
11. A sensor according to claim 1 which detects temperature changes.
12. A sensor according to claim 1 wherein the total surface area of the first electrodes is at least 10% of the total surface area of the first surface and at most 70% of the total surface area of the first surface.
13. A sensor according to claim 1 which comprises an array comprising at least two groups of sensing elements, preferably wherein the groups comprise lines of sensing elements.
14. A lithium ion polymer battery which comprises
(A) a laminar battery element surrounded by an insulating material, said battery element comprising (1) first and second battery electrodes, (2) an anode, (3) a separator, (4) a cathode, and (5) and electrolyte; and
(B) a laminar temperature sensor positioned in direct contact with the insulating material and covering at least 75% of one laminar surface of the insulating material, said sensor having a resistance at 20° C. RT and comprising
(1) a laminar sheet which (a) has a first surface and a second opposite surface, and (b) comprises a conductive polymer composition which exhibits PTC behavior;
(2) a plurality of sensing elements (a) each of which comprises an electrode pair, said electrode pair comprising a first electrode and a second electrode, said electrodes being separated from each other and in contact with the laminar sheet, and (b) which are electrically connected in a resistive network, at least some of said sensing elements connected in series; and
(3) two electrical leads for connecting the sensing elements into a circuit.
15. An electrical circuit which comprises
(A) a laminar sensor for detecting changes on a laminar substrate, the sensor having a resistance at 20° C. RT and comprising
(1) a laminar sheet which (a) has a first surface and a second opposite surface, and (b) comprises a conductive polymer composition which (i) exhibits temperature dependent resistance behavior and (ii) has a switching temperature Ts;
(2) a plurality of sensing elements (a) each of which comprises an electrode pair, said electrode pair comprising a first electrode and a second electrode, said electrodes being separated from each other and in contact with the laminar sheet, and (b) which are electrically connected in a resistive network, at least some of said sensing elements connected in series; and
(3) two electrical leads for connecting the sensing elements into the circuit; and
(B) sensing equipment electrically connected to the electrical leads to detect a change in the sensor.
16. A circuit according to claim 15 wherein the sensing equipment detects a change in resistance of the sensor.
17. A circuit according to claim 15 which further comprises
(C) a source of electrical power which is electrically connected to the sensor, wherein the sensor acts both to detect changes in temperature and as an overcurrent protection device.
18. A circuit according to claim 16 wherein
(1) the sensor comprises an array comprising at least two groups of sensing elements, and
(2) the sensing equipment monitors the groups of sensing elements in the array to allow location of a hot spot.
US10/624,789 1998-10-28 2003-07-22 Sensor Abandoned US20040056753A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US09/182,590 US6137669A (en) 1998-10-28 1998-10-28 Sensor
US09/830,547 US6597276B1 (en) 1998-10-28 1999-10-27 Distributed sensor
US10/624,789 US20040056753A1 (en) 1998-10-28 2003-07-22 Sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US10/624,789 US20040056753A1 (en) 1998-10-28 2003-07-22 Sensor

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
US09/830,547 Continuation US6597276B1 (en) 1998-10-28 1999-10-27 Distributed sensor
PCT/US1999/025351 Continuation WO2000025325A1 (en) 1998-10-28 1999-10-27 Distributed sensor

Publications (1)

Publication Number Publication Date
US20040056753A1 true US20040056753A1 (en) 2004-03-25

Family

ID=22669124

Family Applications (3)

Application Number Title Priority Date Filing Date
US09/182,590 Expired - Fee Related US6137669A (en) 1998-10-28 1998-10-28 Sensor
US09/830,547 Expired - Fee Related US6597276B1 (en) 1998-10-28 1999-10-27 Distributed sensor
US10/624,789 Abandoned US20040056753A1 (en) 1998-10-28 2003-07-22 Sensor

Family Applications Before (2)

Application Number Title Priority Date Filing Date
US09/182,590 Expired - Fee Related US6137669A (en) 1998-10-28 1998-10-28 Sensor
US09/830,547 Expired - Fee Related US6597276B1 (en) 1998-10-28 1999-10-27 Distributed sensor

Country Status (3)

Country Link
US (3) US6137669A (en)
JP (1) JP2002528874A (en)
WO (1) WO2000025325A1 (en)

Cited By (41)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080257706A1 (en) * 2007-04-20 2008-10-23 Haag Ronald H In-molded capacitive switch
US20090019833A1 (en) * 2007-07-19 2009-01-22 Yonushonis Thomas M Apparatus, system, and method for determining a time-temperature history of an aftertreatment device
US20090108985A1 (en) * 2007-04-20 2009-04-30 Ink-Logix, Llc In-molded resistive and shielding elements
EP2340685A1 (en) * 2008-10-24 2011-07-06 Valco Instruments Company, Inc. Adaptive temperature controller
US8283800B2 (en) 2010-05-27 2012-10-09 Ford Global Technologies, Llc Vehicle control system with proximity switch and method thereof
US8454181B2 (en) 2010-08-25 2013-06-04 Ford Global Technologies, Llc Light bar proximity switch
US8575949B2 (en) 2010-08-25 2013-11-05 Ford Global Technologies, Llc Proximity sensor with enhanced activation
US8796575B2 (en) 2012-10-31 2014-08-05 Ford Global Technologies, Llc Proximity switch assembly having ground layer
US8878438B2 (en) 2011-11-04 2014-11-04 Ford Global Technologies, Llc Lamp and proximity switch assembly and method
US20140328373A1 (en) * 2010-06-29 2014-11-06 Indian Institute Of Technology Kanpur Flexible temperature sensor and sensor array
US8922340B2 (en) 2012-09-11 2014-12-30 Ford Global Technologies, Llc Proximity switch based door latch release
US8928336B2 (en) 2011-06-09 2015-01-06 Ford Global Technologies, Llc Proximity switch having sensitivity control and method therefor
US8933708B2 (en) 2012-04-11 2015-01-13 Ford Global Technologies, Llc Proximity switch assembly and activation method with exploration mode
US8975903B2 (en) 2011-06-09 2015-03-10 Ford Global Technologies, Llc Proximity switch having learned sensitivity and method therefor
US8981602B2 (en) 2012-05-29 2015-03-17 Ford Global Technologies, Llc Proximity switch assembly having non-switch contact and method
US8994228B2 (en) 2011-11-03 2015-03-31 Ford Global Technologies, Llc Proximity switch having wrong touch feedback
US9065447B2 (en) 2012-04-11 2015-06-23 Ford Global Technologies, Llc Proximity switch assembly and method having adaptive time delay
US9136840B2 (en) 2012-05-17 2015-09-15 Ford Global Technologies, Llc Proximity switch assembly having dynamic tuned threshold
US9143126B2 (en) 2011-09-22 2015-09-22 Ford Global Technologies, Llc Proximity switch having lockout control for controlling movable panel
US9184745B2 (en) 2012-04-11 2015-11-10 Ford Global Technologies, Llc Proximity switch assembly and method of sensing user input based on signal rate of change
US9197206B2 (en) 2012-04-11 2015-11-24 Ford Global Technologies, Llc Proximity switch having differential contact surface
US9219472B2 (en) 2012-04-11 2015-12-22 Ford Global Technologies, Llc Proximity switch assembly and activation method using rate monitoring
US9287864B2 (en) 2012-04-11 2016-03-15 Ford Global Technologies, Llc Proximity switch assembly and calibration method therefor
US9311204B2 (en) 2013-03-13 2016-04-12 Ford Global Technologies, Llc Proximity interface development system having replicator and method
US9337832B2 (en) 2012-06-06 2016-05-10 Ford Global Technologies, Llc Proximity switch and method of adjusting sensitivity therefor
US20160238457A1 (en) * 2013-10-21 2016-08-18 Parker-Hannifin Corporation Determining an extreme temperature location from a plurality of locations
US9520875B2 (en) 2012-04-11 2016-12-13 Ford Global Technologies, Llc Pliable proximity switch assembly and activation method
US9531379B2 (en) 2012-04-11 2016-12-27 Ford Global Technologies, Llc Proximity switch assembly having groove between adjacent proximity sensors
US9548733B2 (en) 2015-05-20 2017-01-17 Ford Global Technologies, Llc Proximity sensor assembly having interleaved electrode configuration
US9559688B2 (en) 2012-04-11 2017-01-31 Ford Global Technologies, Llc Proximity switch assembly having pliable surface and depression
US9568527B2 (en) 2012-04-11 2017-02-14 Ford Global Technologies, Llc Proximity switch assembly and activation method having virtual button mode
US9641172B2 (en) 2012-06-27 2017-05-02 Ford Global Technologies, Llc Proximity switch assembly having varying size electrode fingers
US9654103B2 (en) 2015-03-18 2017-05-16 Ford Global Technologies, Llc Proximity switch assembly having haptic feedback and method
US9660644B2 (en) 2012-04-11 2017-05-23 Ford Global Technologies, Llc Proximity switch assembly and activation method
US9831870B2 (en) 2012-04-11 2017-11-28 Ford Global Technologies, Llc Proximity switch assembly and method of tuning same
US9944237B2 (en) 2012-04-11 2018-04-17 Ford Global Technologies, Llc Proximity switch assembly with signal drift rejection and method
US9997906B1 (en) * 2017-09-21 2018-06-12 Polytronics Technology Corp. Over-current protection device
US10004286B2 (en) 2011-08-08 2018-06-26 Ford Global Technologies, Llc Glove having conductive ink and method of interacting with proximity sensor
US10038443B2 (en) 2014-10-20 2018-07-31 Ford Global Technologies, Llc Directional proximity switch assembly
US10112556B2 (en) 2011-11-03 2018-10-30 Ford Global Technologies, Llc Proximity switch having wrong touch adaptive learning and method
US10324069B2 (en) 2017-02-24 2019-06-18 Valco Instruments Company, L.P. Chromatographic system temperature control system

Families Citing this family (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6821821B2 (en) * 1996-04-18 2004-11-23 Tessera, Inc. Methods for manufacturing resistors using a sacrificial layer
EP1070944B1 (en) 1998-04-07 2009-06-17 Tyco Electronics Reychem K.K. Secondary cell, temperature detector of secondary cell and method of manufacturing temperature detector
FI121415B (en) * 2001-01-22 2010-11-15 Avantone Oy The layer structure detector and a method of manufacturing the same, and the use of
TW529772U (en) * 2002-06-06 2003-04-21 Protectronics Technology Corp Surface mountable laminated circuit protection device
DE10225938C1 (en) * 2002-06-11 2003-12-18 Webasto Thermosysteme Gmbh Over-heating detector uses temperature sensor in the form of polymer element with fibres or bands extending across monitored surface
US7258520B2 (en) * 2002-08-31 2007-08-21 Applied Materials, Inc. Methods and apparatus for using substrate carrier movement to actuate substrate carrier door opening/closing
US6974661B2 (en) * 2003-01-24 2005-12-13 Hewlett-Packard Development Company, L.P. Compositions, systems, and methods for imaging
US7083904B2 (en) * 2003-09-05 2006-08-01 Hewlett-Packard Development Company, L.P. Compositions, systems, and methods for imaging
WO2005046017A1 (en) 2003-11-07 2005-05-19 Tyco Electronics Raychem K.K. Overheat protection device and electrical system having same
US7601920B2 (en) * 2003-11-18 2009-10-13 Koa Corporation Surface mount composite electronic component and method for manufacturing same
DE102004010713B4 (en) * 2004-03-04 2006-02-02 Epcos Ag Temperature sensor for engine coolant measurement has flat head with flat ceramic sensors in flat hermetic package with flat leads
TWI251076B (en) * 2004-04-16 2006-03-11 Polytronics Technology Corp Temperature sensor
US7513682B2 (en) * 2004-05-11 2009-04-07 Hewlett-Packard Development Company, L.P. Temperature monitoring system
US7198834B2 (en) 2005-03-22 2007-04-03 Hewlett-Packard Development Company, L.P. Imaging media including interference layer for generating human-readable marking on optical media
US7270944B2 (en) * 2005-03-29 2007-09-18 Hewlett-Packard Development Company, L.P. Compositions, systems, and methods for imaging
JP2007040585A (en) * 2005-08-02 2007-02-15 Jbh Co Ltd Temperature sensor, and heating system using the same
JP5098197B2 (en) * 2006-03-27 2012-12-12 株式会社デンソー Energy storage device module
US7815370B2 (en) * 2007-10-11 2010-10-19 Cummins Filtration Ip, Inc. Apparatus, system, and method for detecting temperature threshold events in an aftertreatment device
CN101737135B (en) 2008-11-18 2014-10-01 康明斯滤清系统知识产权公司 Devices, systems and methods of the temperature threshold events detected after the processing apparatus
US8496854B2 (en) * 2009-10-30 2013-07-30 Sabic Innovative Plastics Ip B.V. Positive temperature coefficient materials with reduced negative temperature coefficient effect
DE102011101762A1 (en) * 2011-05-17 2012-11-22 Li-Tec Battery Gmbh A method for increasing the loading capacity of an electrochemical cell sensor, electrochemical cell sensor and their methods of preparation
EP2810033B1 (en) * 2012-01-30 2018-06-20 PST Sensors (Pty) Limited Large area temperature sensor
KR101759806B1 (en) * 2012-11-01 2017-07-19 블루 스파크 테크놀러지스, 인크. Body temperature logging patch
DE102013214448A1 (en) * 2013-07-24 2015-01-29 Robert Bosch Gmbh Method and apparatus for detection of a temperature increase in a variety of electrochemical memory cell
US9343781B2 (en) * 2013-10-29 2016-05-17 Palo Alto Research Center Incorporated Adaptive current-collector electrochemical system
US9532403B2 (en) * 2013-12-04 2016-12-27 Paul KIELAR Heatable surface device
WO2015108465A1 (en) * 2014-01-17 2015-07-23 Conflux Ab Arrangement and method for measuring temperature
CN105115413B (en) * 2015-07-07 2018-06-05 浙江工商大学 Two-dimensional plane strain field sensing element and method for manufacturing the test species matched Modulus
CN104990641A (en) * 2015-07-07 2015-10-21 中国矿业大学 Two-dimensional planar temperature field test sensing element and manufacturing method thereof
DE102015009715A1 (en) * 2015-07-31 2017-02-02 Silas Mehmet Aslan Oblong extensive monitoring device for detecting excess temperatures

Citations (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2278072A (en) * 1939-06-03 1942-03-31 Bell Telephone Labor Inc Electrical resistance device and method of manufacture thereof
US3668373A (en) * 1969-11-04 1972-06-06 Nikolaus Laing Excess temperature switching device
US4237441A (en) * 1978-12-01 1980-12-02 Raychem Corporation Low resistivity PTC compositions
US4251793A (en) * 1978-05-13 1981-02-17 Danfoss A/S PTC Resistor
US4545926A (en) * 1980-04-21 1985-10-08 Raychem Corporation Conductive polymer compositions and devices
US4724417A (en) * 1985-03-14 1988-02-09 Raychem Corporation Electrical devices comprising cross-linked conductive polymers
US4774024A (en) * 1985-03-14 1988-09-27 Raychem Corporation Conductive polymer compositions
US4935156A (en) * 1981-09-09 1990-06-19 Raychem Corporation Conductive polymer compositions
US5049850A (en) * 1980-04-21 1991-09-17 Raychem Corporation Electrically conductive device having improved properties under electrical stress
US5158366A (en) * 1989-05-31 1992-10-27 Kabushiki Kaisha Kobe Seiko Sho Refractory monitoring temperature sensor and refractory erosion location measuring device
US5166658A (en) * 1987-09-30 1992-11-24 Raychem Corporation Electrical device comprising conductive polymers
US5250228A (en) * 1991-11-06 1993-10-05 Raychem Corporation Conductive polymer composition
US5378407A (en) * 1992-06-05 1995-01-03 Raychem Corporation Conductive polymer composition
US5451919A (en) * 1993-06-29 1995-09-19 Raychem Corporation Electrical device comprising a conductive polymer composition
US5582770A (en) * 1994-06-08 1996-12-10 Raychem Corporation Conductive polymer composition
US5663702A (en) * 1995-06-07 1997-09-02 Littelfuse, Inc. PTC electrical device having fuse link in series and metallized ceramic electrodes
US5747147A (en) * 1995-03-22 1998-05-05 Raychem Corporation Conductive polymer composition and device
US5864281A (en) * 1994-06-09 1999-01-26 Raychem Corporation Electrical devices containing a conductive polymer element having a fractured surface
US5977861A (en) * 1997-03-05 1999-11-02 General Electric Company Current limiting device with grooved electrode structure
US6020808A (en) * 1997-09-03 2000-02-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficent device
US6114942A (en) * 1995-08-07 2000-09-05 Kk Raychem PTC device and battery pack using the same
US6124781A (en) * 1998-10-06 2000-09-26 Bourns, Inc. Conductive polymer PTC battery protection device and method of making same
US6130597A (en) * 1995-03-22 2000-10-10 Toth; James Method of making an electrical device comprising a conductive polymer
US6172591B1 (en) * 1998-03-05 2001-01-09 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6300861B1 (en) * 1998-11-04 2001-10-09 Murata Manufacturing Co., Ltd. Organic thermistor device and method of producing same

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4330703A (en) * 1975-08-04 1982-05-18 Raychem Corporation Layered self-regulating heating article
US4255698A (en) * 1979-01-26 1981-03-10 Raychem Corporation Protection of batteries
EP0064334B1 (en) * 1981-04-16 1986-09-24 United Kingdom Atomic Energy Authority Temperature surveillance system
GB8815800D0 (en) * 1988-07-02 1988-08-10 Dowty Electronic Components Improvements relating to batteries
JP2880200B2 (en) * 1989-10-19 1999-04-05 株式会社フジクラ Abnormal heating detection method of electrical component group
JP3961061B2 (en) * 1997-03-24 2007-08-15 トヨタ自動車株式会社 Battery abnormal Atsushi Nobori detection device

Patent Citations (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2278072A (en) * 1939-06-03 1942-03-31 Bell Telephone Labor Inc Electrical resistance device and method of manufacture thereof
US3668373A (en) * 1969-11-04 1972-06-06 Nikolaus Laing Excess temperature switching device
US4251793A (en) * 1978-05-13 1981-02-17 Danfoss A/S PTC Resistor
US4237441A (en) * 1978-12-01 1980-12-02 Raychem Corporation Low resistivity PTC compositions
US4545926A (en) * 1980-04-21 1985-10-08 Raychem Corporation Conductive polymer compositions and devices
US5049850A (en) * 1980-04-21 1991-09-17 Raychem Corporation Electrically conductive device having improved properties under electrical stress
US4935156A (en) * 1981-09-09 1990-06-19 Raychem Corporation Conductive polymer compositions
US4724417A (en) * 1985-03-14 1988-02-09 Raychem Corporation Electrical devices comprising cross-linked conductive polymers
US4774024A (en) * 1985-03-14 1988-09-27 Raychem Corporation Conductive polymer compositions
US5166658A (en) * 1987-09-30 1992-11-24 Raychem Corporation Electrical device comprising conductive polymers
US5158366A (en) * 1989-05-31 1992-10-27 Kabushiki Kaisha Kobe Seiko Sho Refractory monitoring temperature sensor and refractory erosion location measuring device
US5250228A (en) * 1991-11-06 1993-10-05 Raychem Corporation Conductive polymer composition
US5378407A (en) * 1992-06-05 1995-01-03 Raychem Corporation Conductive polymer composition
US5451919A (en) * 1993-06-29 1995-09-19 Raychem Corporation Electrical device comprising a conductive polymer composition
US5582770A (en) * 1994-06-08 1996-12-10 Raychem Corporation Conductive polymer composition
US5864281A (en) * 1994-06-09 1999-01-26 Raychem Corporation Electrical devices containing a conductive polymer element having a fractured surface
US5747147A (en) * 1995-03-22 1998-05-05 Raychem Corporation Conductive polymer composition and device
US6130597A (en) * 1995-03-22 2000-10-10 Toth; James Method of making an electrical device comprising a conductive polymer
US5663702A (en) * 1995-06-07 1997-09-02 Littelfuse, Inc. PTC electrical device having fuse link in series and metallized ceramic electrodes
US6114942A (en) * 1995-08-07 2000-09-05 Kk Raychem PTC device and battery pack using the same
US5977861A (en) * 1997-03-05 1999-11-02 General Electric Company Current limiting device with grooved electrode structure
US6020808A (en) * 1997-09-03 2000-02-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficent device
US6172591B1 (en) * 1998-03-05 2001-01-09 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6124781A (en) * 1998-10-06 2000-09-26 Bourns, Inc. Conductive polymer PTC battery protection device and method of making same
US6300861B1 (en) * 1998-11-04 2001-10-09 Murata Manufacturing Co., Ltd. Organic thermistor device and method of producing same

Cited By (50)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8642931B2 (en) * 2006-03-13 2014-02-04 Valco Instruments Company, L.P. Adaptive temperature controller
US8514545B2 (en) 2007-04-20 2013-08-20 Ink-Logix, Llc In-molded capacitive switch
US20090108985A1 (en) * 2007-04-20 2009-04-30 Ink-Logix, Llc In-molded resistive and shielding elements
US9576755B2 (en) 2007-04-20 2017-02-21 T+Ink, Inc. In-molded resistive and shielding elements
US8198979B2 (en) 2007-04-20 2012-06-12 Ink-Logix, Llc In-molded resistive and shielding elements
US20080257706A1 (en) * 2007-04-20 2008-10-23 Haag Ronald H In-molded capacitive switch
US7572054B2 (en) * 2007-07-19 2009-08-11 Cummins Filtration Ip, Inc Apparatus, system, and method for determining a time-temperature history of an aftertreatment device
US20090019833A1 (en) * 2007-07-19 2009-01-22 Yonushonis Thomas M Apparatus, system, and method for determining a time-temperature history of an aftertreatment device
CN102265703A (en) * 2008-10-24 2011-11-30 万科仪器公司 Adaptive Temperature Controller
EP2340685A1 (en) * 2008-10-24 2011-07-06 Valco Instruments Company, Inc. Adaptive temperature controller
EP2340685A4 (en) * 2008-10-24 2012-04-04 Valco Instr Co Inc Adaptive temperature controller
US8283800B2 (en) 2010-05-27 2012-10-09 Ford Global Technologies, Llc Vehicle control system with proximity switch and method thereof
US20140328373A1 (en) * 2010-06-29 2014-11-06 Indian Institute Of Technology Kanpur Flexible temperature sensor and sensor array
US8454181B2 (en) 2010-08-25 2013-06-04 Ford Global Technologies, Llc Light bar proximity switch
US8575949B2 (en) 2010-08-25 2013-11-05 Ford Global Technologies, Llc Proximity sensor with enhanced activation
US8975903B2 (en) 2011-06-09 2015-03-10 Ford Global Technologies, Llc Proximity switch having learned sensitivity and method therefor
US8928336B2 (en) 2011-06-09 2015-01-06 Ford Global Technologies, Llc Proximity switch having sensitivity control and method therefor
US10004286B2 (en) 2011-08-08 2018-06-26 Ford Global Technologies, Llc Glove having conductive ink and method of interacting with proximity sensor
US9143126B2 (en) 2011-09-22 2015-09-22 Ford Global Technologies, Llc Proximity switch having lockout control for controlling movable panel
US10112556B2 (en) 2011-11-03 2018-10-30 Ford Global Technologies, Llc Proximity switch having wrong touch adaptive learning and method
US8994228B2 (en) 2011-11-03 2015-03-31 Ford Global Technologies, Llc Proximity switch having wrong touch feedback
US8878438B2 (en) 2011-11-04 2014-11-04 Ford Global Technologies, Llc Lamp and proximity switch assembly and method
US9520875B2 (en) 2012-04-11 2016-12-13 Ford Global Technologies, Llc Pliable proximity switch assembly and activation method
US9831870B2 (en) 2012-04-11 2017-11-28 Ford Global Technologies, Llc Proximity switch assembly and method of tuning same
US9065447B2 (en) 2012-04-11 2015-06-23 Ford Global Technologies, Llc Proximity switch assembly and method having adaptive time delay
US9944237B2 (en) 2012-04-11 2018-04-17 Ford Global Technologies, Llc Proximity switch assembly with signal drift rejection and method
US9197206B2 (en) 2012-04-11 2015-11-24 Ford Global Technologies, Llc Proximity switch having differential contact surface
US9219472B2 (en) 2012-04-11 2015-12-22 Ford Global Technologies, Llc Proximity switch assembly and activation method using rate monitoring
US9287864B2 (en) 2012-04-11 2016-03-15 Ford Global Technologies, Llc Proximity switch assembly and calibration method therefor
US9660644B2 (en) 2012-04-11 2017-05-23 Ford Global Technologies, Llc Proximity switch assembly and activation method
US8933708B2 (en) 2012-04-11 2015-01-13 Ford Global Technologies, Llc Proximity switch assembly and activation method with exploration mode
US9559688B2 (en) 2012-04-11 2017-01-31 Ford Global Technologies, Llc Proximity switch assembly having pliable surface and depression
US9531379B2 (en) 2012-04-11 2016-12-27 Ford Global Technologies, Llc Proximity switch assembly having groove between adjacent proximity sensors
US9184745B2 (en) 2012-04-11 2015-11-10 Ford Global Technologies, Llc Proximity switch assembly and method of sensing user input based on signal rate of change
US9568527B2 (en) 2012-04-11 2017-02-14 Ford Global Technologies, Llc Proximity switch assembly and activation method having virtual button mode
US9136840B2 (en) 2012-05-17 2015-09-15 Ford Global Technologies, Llc Proximity switch assembly having dynamic tuned threshold
US8981602B2 (en) 2012-05-29 2015-03-17 Ford Global Technologies, Llc Proximity switch assembly having non-switch contact and method
US9337832B2 (en) 2012-06-06 2016-05-10 Ford Global Technologies, Llc Proximity switch and method of adjusting sensitivity therefor
US9641172B2 (en) 2012-06-27 2017-05-02 Ford Global Technologies, Llc Proximity switch assembly having varying size electrode fingers
US8922340B2 (en) 2012-09-11 2014-12-30 Ford Global Technologies, Llc Proximity switch based door latch release
US9447613B2 (en) 2012-09-11 2016-09-20 Ford Global Technologies, Llc Proximity switch based door latch release
US8796575B2 (en) 2012-10-31 2014-08-05 Ford Global Technologies, Llc Proximity switch assembly having ground layer
US9311204B2 (en) 2013-03-13 2016-04-12 Ford Global Technologies, Llc Proximity interface development system having replicator and method
US10132695B2 (en) * 2013-10-21 2018-11-20 Parker-Hannifin Corporation Determining an extreme temperature location from a plurality of locations
US20160238457A1 (en) * 2013-10-21 2016-08-18 Parker-Hannifin Corporation Determining an extreme temperature location from a plurality of locations
US10038443B2 (en) 2014-10-20 2018-07-31 Ford Global Technologies, Llc Directional proximity switch assembly
US9654103B2 (en) 2015-03-18 2017-05-16 Ford Global Technologies, Llc Proximity switch assembly having haptic feedback and method
US9548733B2 (en) 2015-05-20 2017-01-17 Ford Global Technologies, Llc Proximity sensor assembly having interleaved electrode configuration
US10324069B2 (en) 2017-02-24 2019-06-18 Valco Instruments Company, L.P. Chromatographic system temperature control system
US9997906B1 (en) * 2017-09-21 2018-06-12 Polytronics Technology Corp. Over-current protection device

Also Published As

Publication number Publication date
WO2000025325A1 (en) 2000-05-04
JP2002528874A (en) 2002-09-03
US6137669A (en) 2000-10-24
US6597276B1 (en) 2003-07-22

Similar Documents

Publication Publication Date Title
US4238812A (en) Circuit protection devices comprising PTC elements
US5140297A (en) PTC conductive polymer compositions
CA2345319C (en) Composite electrode including ptc polymer
EP0852801B2 (en) Improved polymeric ptc compositions
EP0038717B1 (en) Electrical devices containing ptc elements
EP0844622B1 (en) Ptc device and battery pack using the same
US4628187A (en) Planar resistance heating element
JP2793790B2 (en) Electrical devices comprising conductive crosslinked polymer
US6642297B1 (en) Polymer composite materials for electrostatic discharge protection
DE2948350C2 (en)
US4413301A (en) Circuit protection devices comprising PTC element
US4857711A (en) Positive temperature coefficient heater
US4967176A (en) Assemblies of PTC circuit protection devices
US4700054A (en) Electrical devices comprising fabrics
US6288372B1 (en) Electric cable having braidless polymeric ground plane providing fault detection
US9401234B2 (en) Over-current protection device
EP0408207B1 (en) Positive temperature coefficient heater
EP0224903B1 (en) Polymer composition having positive temperature coefficient characteristics
JP4188682B2 (en) N-N-m-phenylene-conductive polymer composition comprising a maleimide and elements
US5396177A (en) Battery with electrochemical tester
CA1207466A (en) Ptc circuit protection device
US5227946A (en) Electrical device comprising a PTC conductive polymer
US5195013A (en) PTC conductive polymer compositions
EP0643869B1 (en) Conductive polymer composition
US8686826B2 (en) Surface mountable PPTC device with integral weld plate

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION

AS Assignment

Owner name: LITTELFUSE, INC., ILLINOIS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TYCO ELECTRONICS CORPORATION;REEL/FRAME:039392/0693

Effective date: 20160325