JP2006145478A - Temperature abnormality detection method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature abnormality detection method for specifying a part where temperature abnormality occurs, by detecting the occurrence of the temperature abnormality in a plurality of object locations. <P>SOLUTION: In the temperature abnormality detection method at least two modules 10 are connected serially, including a PTC element 1 and a resistor 2 connected to it, in parallel. The module 10 indicates a low-resistance value (the resistance value of the low-state of the PTC element 1) in a normal temperature state, and is switched with the PTC element 1 so as to indicate mutually different high resistance values (the resistance value of the resistor 2) in a temperature abnormality state. Each module 10 is arranged, by thermally connecting the PTC element 1 at the prescribed object part. A current is made to flow in the module 10 that is connected in series for measuring both-end voltages, the method specifies the module 10 indicating the high resistance value from the values of the both-end voltages, when the both end voltages fluctuate, to detect the occurrence of temperature abnormality, by indicating that one of these is the high-resistance value regarding the time, when all the modules 10 are low-resistance value as a reference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for detecting temperature abnormality at a plurality of target locations by using a PTC element, and an apparatus therefor.

  The “PTC element” means a thermistor having a positive temperature coefficient as known in the field of electric / electronic circuit technology. A PTC element has a low electric resistance under relatively low temperature conditions (for example, at room temperature), but when the temperature exceeds a certain temperature (hereinafter referred to as a trip temperature), the electric resistance rapidly increases. In the present specification, the former state of the PTC element is referred to as a low state, and the latter state is referred to as a high state. Such a temperature-dependent resistance characteristic (or resistance change) of the PTC element is reversible.

  In recent years, PTC elements have been used to detect temperature abnormalities of objects. In particular, when it is desired to detect the occurrence of temperature abnormality at a plurality of target locations at the same time, a PTC element is attached to each location, and the temperature abnormality is detected individually by examining the resistance change of each PTC element. However, more simplified methods are also known in the art.

  As an example of such a conventional temperature abnormality detection method, a plurality of PTC elements connected in series are arranged in contact with a plurality of target locations where temperature abnormality detection is desired, and the resistance change of the entire PTC elements is measured. There is a method for checking (see, for example, Patent Document 1). More specifically, as shown in FIG. 2, a plurality of PTC elements 61 are connected in series, and an ohm meter (resistance measuring device) 62 is connected in series to form an electric circuit (closed loop) to detect temperature abnormality. These PTC elements 61 are used as a device 70 and placed in contact with predetermined target locations where temperature anomalies are to be detected (for example, for each of a plurality of batteries), and the resistance values of the plurality of PTC elements 61 connected in series are ohms. A total of 62 is measured. According to such a method, it is possible to detect the occurrence of a temperature abnormality when a temperature abnormality occurs in any one of a plurality of target places where the PTC element 61 is disposed in contact.

JP-A-10-270094

  However, although the conventional temperature abnormality detection method and apparatus as described above can detect the occurrence of temperature abnormality in a plurality of target portions as a whole, it is not possible to specify the location where the temperature abnormality occurs. That is, when a temperature abnormality occurs in at least one of a plurality of target locations, the “presence / absence” of the occurrence of the temperature abnormality is examined by examining the overall resistance change of the PTC elements arranged in contact with the plurality of target locations. However, it is impossible to know where the temperature abnormality is occurring among the plurality of target portions that are detection targets.

  For example, in a PTC resistance sorter that investigates the temperature-dependent resistance characteristics of manufactured PTC elements and classifies them by spec, the resistance measurement part monitor of the device, the part heated by mechanical action around it, and the vicinity of the monitor action, It is necessary to detect temperature abnormalities at a plurality of target locations and identify the temperature abnormal locations. In such a device, the conventional temperature abnormality detection device as described above cannot be applied, and a temperature abnormality detection device is provided for each portion, and the temperature abnormality is detected individually. . Further, the demand for detecting temperature abnormality at a plurality of target locations and specifying the temperature abnormality location may exist in other monitor systems in which the temperature abnormality becomes a problem.

  The present invention is directed to temperature abnormality detection at a plurality of target locations, and an object of the present invention is to identify a location where a temperature abnormality has occurred when the occurrence of a temperature abnormality is detected. An object of the present invention is to provide a simplified temperature abnormality detection method and an apparatus therefor.

  According to one aspect of the present invention, a module includes a PTC element and a resistor connected in parallel to the PTC element, and each module is in a normal temperature state (or below a predetermined temperature, for example, room temperature, specifically Can be switched by the PTC element so as to show a low resistance value at a temperature of about 0 to 70 ° C. and a high resistance value at a temperature abnormal state (or at a temperature exceeding a predetermined temperature, for example, about 90 to 120 ° C.), At least two modules having different high resistance values are connected in series, and each module is arranged so that the PTC element is thermally coupled to a predetermined target location. Apply a substantially constant current to one module, measure the voltage across the modules connected in series, and use the value of the voltage across all modules as a low resistance value. As any one module shows a high resistance value, when the measured value of both-end voltage fluctuates from the reference value, the module showing the high resistance value is identified from the measured value of the both-end voltage, temperature abnormality detection A method is provided. In addition, a normal temperature state and a temperature abnormal state are distinguished on the basis of the predetermined temperature previously determined according to the use to which this invention is applied.

In the present invention, the “low” resistance value and the “high” resistance value refer to relative sizes of these resistance values. The low resistance value and the high resistance value have a difference of the order of about 10 ⁵ Ω or more, for example, in one PTC element. The low resistance value can be, for example, about 10Ω or less. The high resistance value is not particularly limited as long as it is large enough to be significantly distinguishable from the low resistance value, but may be, for example, about 1 kΩ or more. The low resistance value is preferably a value substantially equal to each other between modules, but the present invention is not limited to this, and may be a value different from module to module (however, even if different) And negligible compared to the difference between high resistance values).

  In this way, since the high resistance value is sufficiently large compared to the low resistance value, even if the low resistance value is different between modules, it can be ignored compared to the difference between modules of high resistance value. The total resistance of the modules connected in series (synthetic resistance) when each module shows a high resistance value alone and the remaining modules show a low resistance value is substantially only high. It changes depending on. In particular, if the low resistance value is substantially equal in all modules, the total resistance (combined resistance) of the modules connected in series varies strictly depending only on the high resistance value.

  Therefore, according to such a configuration, since the high resistance value is different between the modules, each module is obtained for all modules, and each module shows a high resistance value alone, and the remaining modules show a low resistance value. In this case, the total resistance of the modules connected in series, and thus the voltage values at both ends, are unique values in each case and do not match.

  According to such a method of the present invention, when a predetermined target portion where the PTC element of the module is thermally coupled moves from a normal temperature state to a temperature abnormal state, the module exhibits a high resistance value, Therefore, since the measured value of the voltage across the terminal fluctuates (more specifically, increases) from the reference value under a constant current, the occurrence of temperature abnormality can be detected. In addition, since this high resistance value varies from module to module, if any one of the modules shows a high resistance value and the occurrence of a temperature abnormality is detected, which module has a high resistance value from the measured value of both-end voltage. In other words, it is possible to specify where the temperature abnormality has occurred.

  More specifically, the voltage of both ends (the voltages of both ends of the modules connected in series) obtained for all modules when each module shows a high resistance value alone and the remaining modules show a low resistance value. A group of values (in other words, the voltage across the case where only one module showed a high resistance value and all the remaining modules showed a low resistance value was obtained for each case for all modules. A module showing a high resistance value can be identified by finding a value substantially equal to the measured value of the voltage between both ends from the set of values). The group consisting of the voltage values at both ends may be either theoretical calculation or actual measurement when performing temperature abnormality detection, but is preferably obtained in advance.

In order to facilitate understanding, a case where three modules A, B and C connected in series (assumed to be connected in series in this order) will be described as an example. In this case, these high resistance values (referred to as R _A , R _B and _RC , respectively) are set to be “different from one another between modules” and are different from each other (ie, any two values are different from each other). ).

In addition, “a group consisting of the values of the voltage of both ends of modules connected in series when each module shows a high resistance value alone and the remaining modules show a low resistance value” is obtained for all modules. , Means a group (or set) of values of voltage across modules A-C, obtained for every case of selecting one module from all modules A, B and C. That is, only the module A shows a high resistance value, the value of the voltage across the module A~C when the remaining modules B and C indicates a low resistance value (hereinafter the same) (the V _1), module B only Indicates a high resistance value, and when the remaining modules A and C exhibit a low resistance value, the value of the voltage between both ends (V ₂ ), only the module C exhibits a high resistance value, and the remaining modules B and A This means a group {V ₁ , V ₂ , V ₃ } consisting of the voltage values (V ₃ ) at both ends in the case of showing a low resistance value (see cases 1 to 3 in Table 1). Since R _A , R _B and R _C are different from each other, in each case, the total resistances (combined resistances) of the modules A, B and C are also different (see the above description). ₁ , V ₂ , and V ₃ are also different from each other. These voltage values at both ends may be theoretical values or measured values. Note that the reference value (V ₀ ) of the both-end voltage when all the modules A, B and C exhibit low resistance values is smaller than any of V ₁ , V ₂ and V ₃ , preferably far Small.

Next, in order to detect temperature abnormality, the voltage across the modules A to C is actually measured (measured value V), and the voltage across the module {V ₁ , V ₂ , V ₃ } is measured. By finding a value substantially equal to the value V, it is possible to identify which module exhibits a high resistance value (ie, is in a temperature abnormal state). For example, if substantially equal to the measured value V is V ₁ of the voltage across, 1 if the voltage across V ₁ (see Table 1) only obtained there, therefore, if the module corresponding to 1 A Indicates a high resistance value, and it can be seen that a temperature abnormality has occurred at a location where the module A (more specifically, a PTC element included therein) is arranged. Note that the measured value V (= V ₀ ) of both-end voltages in a state where no temperature abnormality has occurred (that is, when all the modules A, B and C show low resistance values) are V ₁ , V ₂ and V _It can be distinguished from these values because it is smaller than any value of ₃ , preferably much smaller.

  According to another aspect of the present invention, there is provided a device for detecting a temperature abnormality, including at least two modules connected in series, each module being thermally coupled to a predetermined target location. Including a PTC element to be arranged and a resistor connected in parallel to the PTC element, exhibiting a low resistance value in a normal temperature state (or below a predetermined temperature), and in a temperature abnormal state (or exceeding a predetermined temperature) A device is provided that can be switched by a PTC element to exhibit a high resistance value, and the high resistance value is different from module to module.

  By using such an apparatus of the present invention, the above-described method of the present invention can be carried out, and the same effects as the method can be achieved.

  The PTC element used in the method and apparatus of the present invention has a trip temperature that is substantially equal to or close to a temperature (predetermined temperature) that is a criterion for temperature abnormality. The at least two PTC elements used in the present invention can have various temperature-dependent resistance characteristics depending on the application for which temperature abnormality detection is desired, and even if they have substantially the same temperature-dependent resistance characteristics, They may have different temperature dependent resistance characteristics.

  In the present invention, “thermally coupling” a PTC element to a predetermined target location means that the PTC element is placed under the influence of the temperature of the location. For example, it indicates that the PTC element is at least partially in contact with a predetermined target location, preferably in close contact with it. As in the present invention, by thermally coupling the PTC element to a predetermined target location, the resistance of the PTC element can be changed depending on the temperature of the predetermined target location. Temperature abnormality can be detected. More specifically, the PTC element is in a low state when the predetermined target location is at or below the trip temperature and exhibits a low resistance value, but when the temperature exceeds the trip temperature due to overheating, etc. The element goes high and its resistance increases rapidly.

  In addition, the resistor used in parallel connection with the PTC element in the present invention may be a general resistor, but it is not limited to the resistor itself as long as it substantially functions as a resistor. Furthermore, the number of resistors (or resistors) is not necessarily one in each module, and any configuration may be employed as long as a plurality of resistors (or resistors) are connected in parallel to the PTC element as a whole. For example, two or more resistors may be connected in parallel to the PTC element, and the two or more resistors may be considered as a single resistor connected in parallel to the PTC element.

  In a preferred embodiment of the present invention, when one or two or more modules exhibit a high resistance value, and the measured value of the voltage across the terminal fluctuates from the reference value, the module indicating the high resistance value is It can be identified from the measured value. This is a group consisting of (a) the high resistance value of each module, and (b) the sum of the high resistance values of those two or more modules obtained for all combinations of two or more modules (in other words, The high resistance value of one or more modules, or the sum of the high resistance values in the case of two or more, obtained for all cases of one or more modules selected from all modules This can be implemented by configuring each module such that any two values selected from the group consisting of:

  Therefore, according to such a configuration, any one value or the sum of two or more of the high resistance values are different from each other. Therefore, each module obtained for all the modules exhibits a high resistance value independently. And when the remaining module exhibits a low resistance value and for all combinations of two or more modules, the two or more modules exhibit a high resistance value and the remaining modules exhibit a low resistance value. In this case, the total resistance of the modules connected in series, and thus the value of the voltage at both ends, is a unique value in each case and does not match.

  Therefore, not only when one module shows a high resistance value, but also when two or more modules show a high resistance value at the same time, which module has a high Whether the resistance value is indicated can be uniquely specified.

  More specifically, (i) the voltage obtained across all modules, when each module alone exhibits a high resistance value and the remaining modules exhibit a low resistance value (both ends of the modules connected in series) Voltage), and (ii) obtained for all combinations of two or more modules, where two or more modules exhibit high resistance values and the remaining modules exhibit low resistance values (all (I) only one module exhibits a high resistance value, and all the remaining modules have a low resistance. The voltage at both ends in the case of showing a value is a subset of values obtained for each case for all modules, and (ii) only two or more modules show a high resistance value and the remaining The voltage between both ends when all the modules of (1) show a low resistance value is obtained from the entire set consisting of a subset of values obtained in each case for all combinations of two or more modules). By finding a value that is substantially equal to the measured value, a module that exhibits a high resistance value can be identified. The group consisting of the voltage values at both ends may be either theoretical calculation or actual measurement when performing temperature abnormality detection, but is preferably obtained in advance.

In order to facilitate understanding, an example in which the three modules A, B, and C (the high resistance values are R _A , R _B, and R _C , respectively) in the above example will be described. In this case, “(a) a high resistance value of each module, and (b) a group consisting of the sum of the high resistance values of those two or more modules obtained for all combinations of two or more modules”. (A) a subset {R _A , R _B , R _C } consisting of the high resistance value of each module, and (b) those particular two or more obtained for all combinations consisting of two or more modules. It means a group (or entire set) composed of a subset {R _A + R _B , R _A + R _C , R _B + R _C , R _A + R _B + R _C } composed of the sum of high resistance values of modules (table) 1). The high resistance values R _A , R _B and R are selected from this group (entire set), in other words, so that any two values are different from each other. _C is set.

In addition, “(i) obtained for all modules, the value of the voltage between both ends of the modules connected in series when each module independently exhibits a high resistance value and the remaining modules exhibit a low resistance value, and ( ii) The voltage across the series connected modules obtained for all combinations of two or more modules when the two or more modules exhibit a high resistance value and the remaining modules exhibit a low resistance value. Is a group (or set of voltage values across modules A to C obtained for all cases where one or more modules are selected from all modules A, B and C). ). That is, as shown in Table 1 in the case of 1 to 7, only the selected specific (i) one module or (ii) two or more modules show a high resistance value (temperature abnormality), and the remaining modules are low. A group {V consisting of values of both-end voltages obtained for cases where resistance values are shown (however, when all modules A, B and C show high resistance values, there is naturally no module showing low resistance values). ₁ , V ₂ , V ₃ , V ₄ , V ₅ , V ₆ , V ₇ } (see Table 1). As mentioned _{above, R A, R B, R} C, R A + R B, R A + R C, since R B + _{R C} and _R A _{+ R} B _{+ R C} are different from one another, in each case, modules A, B and The total resistance (combined resistance) of C is also different, and thus the voltage values V _{1 to} V _{7 at} both ends are also different from each other. These voltage values at both ends may be theoretical values or measured values.

Next, the voltage across the modules A to C is actually measured (measured value V) for temperature abnormality detection, and the voltage across the group {V ₁ , V ₂ ,..., V ₇ } is measured. By finding a value substantially equal to the measured value V, it is possible to identify which module exhibits a high resistance value (i.e., is in an abnormal temperature state). For example, if substantially equal to the measured value V is V ₄ across the voltage, the voltage across (see Table 1) 4 as the V ₄ only obtained there, thus, when corresponding to the four modules A And B show high resistance values, and it can be seen that a temperature abnormality has occurred at the location where the modules A and B (more specifically, the PTC elements included therein) are arranged.

  In the present specification, the term “substantially equal (or substantially the same)” is not limited to the case where they are completely coincident with each other, and it is allowed to have a slight difference within a range that can achieve the object of the present invention. It is used for the purpose. For example, the “substantially equal value” refers to a value that can be regarded as equal while taking into account measurement errors of a device such as a voltmeter, errors due to environmental factors, and the like.

  Further, in this specification, “finding” a value substantially equal to the measured value of the voltage across the terminal means that the measured value of the voltage across the terminal is substantially equal to the measured value of the voltage across the terminal from any group of voltage values that may be prepared in advance. Means to search for and extract a value equal to some method, and by examining the module (one or a combination of two or more) that yields the extracted value, a temperature anomaly module (ie, indicating a high resistance value) Module). For example, by sequentially comparing one value in a group of values of the both-end voltage obtained in advance (see, for example, Table 1) and the measured value of the both-end voltage (for example, the magnitude of the difference between the two) By determining the value, a value substantially equal to the measured value of the voltage across both ends can be “found” from the group of values of the voltage across the ends.

In one embodiment of the present invention, when n modules connected in series (naturally, n is an integer of 2 or more, and so on) are used, the ratio of the high resistance values of the modules is Z ⁰ : Z ¹ : ..: Z ^m :...: Z ^n-1 (Z is a predetermined real number larger than 1 and m is an integer of 1 to n-1). If a high resistance value is selected in this way, (a) the high resistance value of each module, and (b) the sum of the high resistance values of two or more modules obtained for any combination of two or more modules. Any two values selected from the group are different from each other, and no two of them will match.

However, it should be noted that the above aspect is only one aspect of practicing the present invention. That is, the present invention is not limited to this, and any one selected from the group consisting of the high resistance value of each module and the sum of the high resistance values of the two or more modules in all combinations of two or more modules. Any high resistance value may be selected as long as the two values are different from each other. For example, the ratio of the high resistance values of the modules is Z ^x1 : Z ^x2 :...: Z ^xm :... (Z is a predetermined real number greater than 1), and xm (x1, x2,...) Any suitable real number may be used, and those skilled in the art will be selected from the group consisting of the high resistance value of each module and the high resistance value of the two or more modules in all combinations of two or more modules. The value of xm could be chosen appropriately so that any two values are different from each other. Further, for example, the high resistance value of each module may be determined by any appropriate method, for example, a trial and error or a mathematical (or mathematical) approach.

  In one aspect of the invention, the low resistance value of the module is substantially equal to the low state resistance value of the PTC element included in the module, and the high resistance value of the module is the resistance value of the resistor included in the module. Is substantially equal. According to such a configuration, it is possible to easily determine the high resistance value of each module, which is a parameter for specifying the module in the abnormal temperature state, by appropriately selecting the resistivity of the resistor.

For example, when using the n modules comprising connected in series, the ratio of the high resistance of the module ^{is, Z 0: Z 1: ···} : Z m: ···: Z n-1 (Z than 1 In order to configure each module as represented by a large predetermined real number, m is an integer of 1 to n−1, the ratio of the resistance values of the resistors included in each module is represented in this way. What is necessary is just to comprise each resistor.

  However, the present invention is not limited to this, and the module includes a PTC element and a resistor connected in parallel to the PTC element, and exhibits a low resistance value in a normal temperature state, and varies between modules in a temperature abnormal state. Switchable by a PTC element to indicate a high resistance value, preferably selected from the group consisting of the high resistance value of each module and the high resistance value of the two or more modules in any combination of two or more modules As long as any two values are different from each other, the module may have any internal configuration.

  In a preferred embodiment of the present invention, a polymer PTC element is used as the PTC element. As used herein, “polymer PTC element” refers to an element generally known as such in the field of electrical / electronic circuit technology, or as a PPTC element or polyswitch ™. The polymer PTC element typically has a structure in which a polymer layer in which a conductive filler is dispersed is sandwiched between two metal electrode foils. The polymer PTC element has a larger difference between the resistance value in the low state and the resistance value in the high state than other PTC elements, for example, ceramic PTC elements (CPTC elements), and the rise of the resistance with respect to temperature change is steep. In the CPTC element, the resistance increases when the temperature becomes too low (that is, the temperature coefficient is reversed from positive to negative), but such a phenomenon does not occur in the polymer PTC element. Therefore, it is particularly appropriate to use a polymer PTC element in order to achieve the object of the present invention.

  Note that the method of the present invention is preferably performed by passing a substantially constant current through a plurality of modules connected in series, and measuring the voltage between both ends with a voltmeter in order to detect a temperature abnormality. obtain. However, the present invention is not limited to this, and for example, the total resistance of a plurality of modules connected in series may be measured with an ohmmeter. Further, from the viewpoint of lowering power consumption in a normal temperature state, a PTC element having a low resistance value as high as possible is selected and used within a range not departing from the concept of the present invention, and a constant current value at the time of monitoring is used. Is preferably set small.

  Further, in the present invention, the plurality of predetermined target portions that are targets of temperature abnormality detection are those in two or more objects (for example, one place for each target object) even if they are in the same target object. May be.

  ADVANTAGE OF THE INVENTION According to this invention, while detecting the temperature abnormality generation | occurrence | production in a some target location, the temperature abnormality detection method and apparatus for it which can identify a temperature abnormality generation location are provided. The method and apparatus of the present invention enables a simplified system configuration compared to a method of individually examining resistance changes of PTC elements arranged at each location in order to detect temperature abnormalities at a plurality of target locations. In addition, there is an advantage that it is possible to specify a temperature abnormal portion, which is impossible when detecting an abnormal temperature by examining an overall resistance change of a plurality of PTC elements arranged in each portion.

BEST MODE FOR CARRYING OUT THE INVENTION

  One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an electric circuit diagram of a temperature abnormality detection device 20 used in the present embodiment.

  As shown in FIG. 1, the temperature abnormality detection device 20 is an electric circuit (closed loop) formed by connecting n (n is an integer of 2 or more) modules 10 in series and a constant current power supply device 11 connected in series thereto. Have In this electric circuit, a voltmeter 12 is inserted in parallel with these modules 10 in order to measure the voltage across n modules 10 connected in series.

  As illustrated, each module 10 includes a PTC element 1 and a resistor 2 connected in parallel to the PTC element 1 so that a current flowing through the module 10 flows through the PTC element 1 and / or the resistor 2. It has become. The PTC element 1 is preferably a polymer PTC. A particularly preferred polymer PTC element is a polymer PTC element having a structure in which polyethylene in which carbon black is dispersed is sandwiched between a pair of electrodes of a Ni-plated Cu foil and an unplated Cu foil. As the resistor 2, a commercially available suitable fixed resistor can be used. Since the constant current power supply device 11 and the voltmeter 12 are common in the technical field, description thereof is omitted. The constant current power supply device 11 and the voltmeter 12 are a DC power supply and a DC voltmeter in this embodiment.

  The trip temperature of the PTC element 1 serves as a criterion for determining a temperature abnormality, and is substantially the same as or close to a predetermined temperature used as a criterion for determining a temperature abnormality. The trip temperature can be appropriately selected depending on the application, for example, in the range of about 90 to 120 ° C.

  The resistance of the module 10 is obtained as a combined resistance CR of the PTC element 1 and the resistor 2 (CR = P · R / (P + R), where P is the resistance value of the PTC element 1 and R is the resistance of the resistor 2. Value).

The resistance value of the PTC element 1 in the low state (P _low ), the resistance value in the high state (P _high , generally referred to as a high impedance state), and the resistance value (R) of the resistor 2 are the low resistance value of each module 10 and The high resistance value is appropriately selected to be substantially equal to P _low and R, respectively. More specifically, for example, the PTC element 1 and the resistor so that R is 100 times or more of P _low and 1/100 times or less of P _high (P _low × 100 ≦ R ≦ P _high × 1/100). 2 can be configured. If R is 100 times P _low or more, the resistance of the module 10 can be regarded as being substantially equal to P _low in the normal temperature state (the PTC element 1 is in the low state) (CR ≈ P from P _low + R≈R). _low ). Further, if R is 1/100 times or less of P _high , the resistance of the module 10 can be regarded as being substantially equal to R in a temperature abnormal state (the PTC element 1 is in a high state) (P _high + R≈P _high CR≈R). R is, for example, about 10 to 1000 times, preferably about 100 to 1000 times P _low , and is about 1/10 to 1/1000 times, preferably about 1/100 to 1/1000 times P _high. The

Between the modules 10, the resistors 2 have different resistance values. In this embodiment, the ratio of the resistance values of the resistors 2 provided in each of the n modules 10 (in other words, the ratio of the high resistance values of the modules 10) is Z ⁰ : Z ¹ :... Z ^m : ...: Zn ^-1 (Z is a predetermined real number larger than 1 and m is an integer of 1 to n-1). That is, the magnitude of the resistance value of the resistor 2 is generally represented by kZ ^m (k is a positive proportionality constant). With such a configuration, the high resistance values (kZ ⁰ , kZ ¹ ,..., KZ ^m ,..., Z ^n-1 ) of each module 10 and those obtained for any combination of two or more modules. Sum of high resistance values of modules (kZ ⁰ + kZ ¹ , kZ ⁰ + kZ ² ,..., KZ ⁰ + kZ ^m ,..., KZ ⁰ + Z ⁿ⁻¹ ; kZ ¹ + kZ ² ,..., KZ ¹ + kZ ^m ,..., kZ ¹ + Z ⁿ⁻¹ ;...; any two values arbitrarily selected from the group consisting of kZ ⁰ + kZ ¹ +... + Z ⁿ⁻¹ ) It will be readily appreciated by those skilled in the art that they are different from and inconsistent with each other. The size of n, Z and k is limited in consideration of the value of P _high of the PTC element 1 in relation to the maximum resistance value (kZ ⁿ ) of the resistor 2 (kZ ⁿ ≦ It should be noted that not only P _high × 1/100) but also the measurement accuracy is limited as described later.

On the other hand, in the present embodiment, the PTC element 1 has substantially the same temperature-dependent resistance characteristics between the modules 10, and thus has substantially the same P _low and P _high. It is not limited to.

The total resistance (combined resistance) of the n modules 10 connected in series is obtained as the sum of the resistances of the modules 10. Therefore, in this embodiment, the total resistance is n × P _low in the normal temperature state, and in the abnormal temperature state, for example, when the abnormal temperature state is detected by one module (m) (n −1) × P _low + kZ ^m The total resistance of the n modules 10 in the abnormal temperature state is different in all cases depending on which module 10 (one or two or more) has a temperature abnormality. As a result, the value of the both-end voltage shown in the abnormal temperature state also becomes a different value in all cases depending on which module 10 (one or two or more) has the abnormal temperature.

  Each module 10 may be sealed with, for example, a resin mold or film lamination, but is not limited thereto, and may have any other appropriate form.

  Next, a temperature abnormality detection method using the temperature abnormality detection device 20 as described above will be described.

  First, the above-mentioned n modules 10 are placed in a PTC at a predetermined target location (n locations) of an object for which temperature abnormality detection is desired (whether the object itself is one or plural). Each element is arranged so as to be thermally coupled thereto. For example, the module 10 can be disposed in close contact with a predetermined target portion using screwing, heat-resistant tape, hot melt material, or the like. The PTC element 10 is placed under the influence of temperature by being thermally coupled to the predetermined target portion.

  Next, a predetermined current is passed through the n modules 10 connected in series using the constant current power supply device 11 of the temperature abnormality detection device 20, and the voltage across the n modules 10 is measured by the voltmeter 12.

The voltage value (measured value or theoretical value) at both ends when all the modules 10 are in a normal temperature state and show a low resistance value (P _low ) is used as a reference value. The voltage across the object is measured (e.g., continuously or periodically) while the object is subjected to testing or while the object is used. When the place where the module 10 is arranged moves from the normal temperature state to the abnormal temperature state, only the module 10 exhibits a high resistance value (R), and as a result, the measured value of the voltage across the terminal fluctuates from the reference value. When such a variation is measured, it is understood that a temperature abnormality has occurred.

  Further, in the above case, a module showing a high resistance value (R) (that is, in a temperature abnormal state) is specified from the measured value of the voltage across the both ends. Since the high resistance values of the modules 10 are different from each other, when any one of the modules 10 exhibits a high resistance value, the module 10 is identified from the measured value of the voltage at both ends to determine which module 10 is in an abnormal temperature state. be able to. In addition, in the present embodiment, the high resistance value of the module 10 is calculated from (a) the value in the case of each single module, and (b) the sum of the values in all combinations of two or more modules. Any two values selected from the group are different from each other and set so as not to match. Therefore, even if not only one but also two or more modules 10 are simultaneously showing a high resistance value, which module 10 is in an abnormal temperature state is uniquely determined from the measured value of the voltage at both ends. Can be identified.

  Such specification is (i) obtained for all modules, the value of the both-end voltage when each module alone exhibits a high resistance value, and the remaining modules exhibit a low resistance value, and (ii) 2 A group consisting of the values of both-end voltages obtained when all the combinations of two or more modules have a high resistance value and the remaining modules have a low resistance value is obtained in advance. This can be done by finding a value from this group that is substantially equal to the measured value of the voltage across it.

  For example, for any combination of one or more modules, the value of the voltage that is assumed or measured when the particular module detects a temperature abnormality, and an identification label for identifying the temperature abnormality module (for example, , A table (for example, a table composed of a column of temperature abnormal modules and a column of voltage values at both ends (each value is a specific value) in Table 1) that associates numbers with numbers such as alphabets and numbers). In addition, the temperature abnormality module can be used to specify the measured value of the voltage across the both ends. Such a table may be used by an operator, or may be used by executing a program by an electronic computer, for example. Such an embodiment is particularly useful when the number of modules (n) is large.

In order to identify the module 10 in the abnormal temperature state, the measured value of the both-end voltage when only the module 10 including the resistor 2 having the minimum resistance value (kZ ⁰ = k) is in the abnormal temperature state, n It is necessary to be able to distinguish significantly the measured value of the voltage between both ends when all the modules 10 are in the abnormal temperature state. Therefore, it should be noted that the values of n, Z, and k are limited in consideration of the measurement accuracy of the voltmeter 12 in a state where a constant current is supplied by the constant current power supply device 11. n may be 2 to 10, for example, Z may be a real number greater than 1, for example, and less than or equal to 2, and k may be a real number in the range of 1 to 100, preferably about 1.

In this embodiment, for example, a polymer PTC element in which P _low is 1Ω, P _high is 100 MΩ, the trip temperature is 120 ° C., and the resistance value at the time of trip is 1 MΩ, the resistance value is 1 kΩ, 2 kΩ,. ^When the resistor 2 (ie, Z = 2, k = 1000) with ^m kΩ,..., 2 ⁿ⁻¹ kΩ is used and a current of about 1 mA is supplied by the constant current power supply device 11, the number of modules ( n) can be, for example, about 2 or more, preferably about 2 to 8. However, the present invention is not limited to this as long as at least two modules are used.

As the PTC element 1, it is preferable to use a polymer PTC element as in the present embodiment. Since a polymer PTC element generally has a difference between a resistance value (P _low ) in a _low state and a resistance value (P _high ) in a high state (hereinafter simply referred to as a resistance value difference), The width from the minimum value to the maximum value of the resistance value of the resistor 2 can be made wider than when a ceramic PTC element having the difference of about 4 digits is used. The polymer PTC element has a steep rise in electrical resistance with respect to temperature change and a large resistance value difference. Therefore, the voltage rise at both ends is higher than that in the case of using a ceramic PTC element with a relatively slow rise and small resistance value difference. The reliability of the measured value is high (in other words, the error is small), and the measurement accuracy can be improved. Therefore, a polymer PTC element is suitable for detecting temperature abnormality in as many locations as possible.

  As described above, according to the present embodiment, it is possible to simultaneously detect the occurrence of temperature abnormalities at a plurality of target locations and specify the location where the temperature abnormality has occurred (or temperature abnormality module). In particular, according to the present embodiment, the resistance value of each resistor included in each module (the sum of the resistance values in the case of two or more) is different from each other for any combination of one or two. Of course, when a temperature abnormality occurs in one module, it is possible to uniquely identify which module is in a temperature abnormality state even when two or more modules have a temperature abnormality at the same time. Can do.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this, and those skilled in the art will understand that various modifications can be made without departing from the concept of the present invention. Let's go. The temperature abnormality detection method and apparatus according to the present invention are concerned with the occurrence of local temperature abnormality in an object such as a production facility such as an electronic component, for example, in any application where temperature abnormality detection is desired at a plurality of target locations. Inspection equipment that inspects the temperature characteristics of individual objects such as manufacturing equipment and electronic parts inspection equipment, or an overheat protection device when using individual objects such as batteries using a number of secondary batteries It could be used in various applications.

It is an electric circuit diagram of the temperature abnormality detection apparatus in one aspect of the present invention. It is an electrical circuit diagram of the conventional temperature abnormality detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PTC element 2 Resistor 10 Module 11 Constant current power supply device 12 Voltmeter 20 Temperature abnormality detection apparatus 61 PTC element 62 Ohm meter 70 Temperature abnormality detection apparatus

Claims (11)

A method for detecting temperature anomalies,
At least two modules including a PTC element and a resistor connected in parallel to the PTC element are connected in series;
Each module can be switched by a PTC element so as to exhibit a low resistance value in a normal temperature state and a high resistance value in a temperature abnormal state, and the high resistance value is different from one module to another.
Each module is arranged so that the PTC element is thermally coupled to a predetermined target location,
Passing a substantially constant current through at least two modules connected in series to measure the voltage across the modules connected in series;
The high resistance value is obtained when the measured value of the voltage at both ends fluctuates from the reference value because any one of the modules exhibits a high resistance value with the value of the voltage at both ends when all the modules exhibit a low resistance value as a reference value. Identifying a module indicative of from a measurement of the voltage across it.   Measurement of both-end voltage obtained from the group consisting of the values of both-end voltage of modules connected in series when each module shows high resistance value alone and the remaining modules show low resistance value obtained for all modules The method of claim 1, wherein a module exhibiting a high resistance value is identified by finding a value substantially equal to the value. Any two values selected from the group consisting of the high resistance value of each module and the sum of the high resistance values of the two or more modules obtained for all combinations of two or more modules are different from each other;
The module showing the high resistance value is identified from the measured value of the both-end voltage when the measured value of the both-end voltage varies from the reference value due to one or more modules exhibiting the high-resistance value. The method according to 1.   It is obtained for all modules, and consists of two or more modules, and the value of the voltage across the modules connected in series when each module exhibits a high resistance value alone and the remaining modules exhibit a low resistance value. Obtained for all combinations from the group consisting of the values of the voltage across the modules connected in series when the two or more modules exhibit a high resistance value and the remaining modules exhibit a low resistance value. 4. The method of claim 3, wherein a module exhibiting a high resistance value is identified by finding a value substantially equal to the measured value of. A device for detecting a temperature abnormality,
Including at least two modules connected in series;
Each module includes a PTC element that is thermally coupled to a predetermined target location and a resistor connected in parallel to the PTC element, and exhibits a low resistance value in a normal temperature state, and in a temperature abnormal state. It can be switched by the PTC element to show a high resistance value,
The device, wherein the high resistance value is different between modules.   Any two values selected from the group consisting of the high resistance value of each module and the sum of the high resistance values of the two or more modules obtained for all combinations of two or more modules are different from each other; The apparatus according to claim 5. It includes n modules connected in series, and the ratio of the high resistance values of the modules is Z ⁰ : Z ¹ : ...: Z ^m : ...: Z ^n-1 (Z is a predetermined value greater than 1) The apparatus according to claim 6, represented by a real number, m is an integer of 1 to n−1.   The low resistance value of the module is substantially equal to a low resistance value of a PTC element included in the module, and a high resistance value of the module is substantially equal to a resistance value of a resistor included in the module. The apparatus in any one of -7. It includes n modules connected in series, and the ratio of the resistance values of the resistors included in each module is Z ⁰ : Z ¹ : ...: Z ^m : ...: Z ^n-1 (Z is The apparatus according to claim 8, represented by a predetermined real number greater than 1, m being an integer from 1 to n−1.   The apparatus according to claim 5, wherein the PTC element is a polymer PTC element.   The method in any one of Claims 1-4 using the apparatus in any one of Claims 5-10.

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