Monitoring device, monitoring system and damage evaluation system

Abstract

The invention provides a monitoring device, a monitoring system and a damage evaluation system, which can continuously monitor a monitored object in a battery-free and maintenance-free manner even if the storage capacity is small. The monitoring device is a device using, as a sensor, a thermal battery having a thermal power generation element that outputs a voltage corresponding to a temperature difference between a temperature of an atmosphere covering a monitoring object and a temperature of a contact portion of the monitoring object, the monitoring device comprising: a booster circuit that boosts the temperature of the atmosphere; a step-up unit that outputs a step-up voltage obtained by step-up of a voltage input from the thermal battery; a power storage element connected to the output end of the booster circuit, the power storage element storing power supplied from a thermal battery as a sensor and boosted by the booster circuit; a voltage detection circuit that outputs a control signal including a signal level corresponding to whether or not the detected boost voltage exceeds a predetermined voltage; and a switch that opens / closes a path connecting the first end and the second end connected to the output end.

Description

Technical Field

[0001] This invention relates to a monitoring device, a monitoring system, and a damage assessment system. Background Technology

[0002] A monitoring device for monitoring the temperature of a wire connection point without a battery (hereinafter referred to as "conventional battery-free monitoring device") is proposed (see, for example, Japanese Patent Application Publication No. 2021-30770). Conventional battery-free monitoring devices are constructed by including a power supply unit with a solar cell, a power storage device, and a power management unit (see, for example, Japanese Patent Application Publication No. 2021-30770). Figure 2 In the power supply section, solar cells generate electricity using sunlight. Energy storage devices are charged by the solar cells and supply power by discharging. Power management circuitry controls the charging and discharging of the energy storage devices. Summary of the Invention

[0003] [The problem the invention aims to solve]

[0004] Existing battery-free monitoring devices use electricity generated by solar cells to power the charging of energy storage devices. Solar cells cannot generate electricity in the absence of sunlight, at night, or in rainy weather. Furthermore, because the solar cells sometimes fail to generate their full power output due to dirt or other contaminants on their surface, maintenance such as cleaning the solar cell surface is necessary.

[0005] Because of this, existing battery-free monitoring devices include structures designed to enable the monitoring device to operate stably for extended periods. Examples of structures designed to enable stable operation of the monitoring device over the desired period include those that are no longer battery-free but instead utilize a primary battery as an auxiliary power source, or those that employ a capacitor with a large capacitance compared to other capacitors, such as an electric double-layer capacitor.

[0006] However, the structure used to ensure stable operation of the monitoring device during the desired period can be considered a scalable structure as long as it can reliably generate electricity, thus leaving room for improvement for battery-free monitoring devices. Furthermore, in existing battery-free monitoring devices, there is room for improvement in maintainability due to the maintenance of the solar cells that serve as the power source. Moreover, if a structure for stable operation of the monitoring device during the desired period is not required, there is also the secondary advantage of facilitating further miniaturization of the device.

[0007] The present invention was made to solve the aforementioned problems, and aims to provide a monitoring device, monitoring system, and damage assessment system that can continuously monitor the monitored object in a battery-free and maintenance-free manner even with a small energy storage capacity.

[0008] [Technical means to solve the problem]

[0009] A monitoring device according to at least one embodiment of the present invention is installed on a monitored object. A thermal battery having a thermal power generation element (i.e., a voltage corresponding to the temperature difference between the temperature of the atmosphere surrounding the monitored object and the temperature of the contact portion in contact with the monitored object) is used as a sensor. The monitored object is monitored based on the voltage corresponding to the temperature difference. The monitoring device includes: a boost circuit, including an input terminal receiving voltage from the thermal battery and an output terminal outputting a boosted voltage obtained by boosting the voltage input from the input terminal; a power storage element connected to the output terminal of the boost circuit and storing the power supplied from the thermal battery (serving as the sensor) and boosted by the boost circuit; a voltage detection circuit detecting the boosted voltage and outputting a control signal from the output terminal, the control signal including signal levels corresponding to when the boosted voltage exceeds a predetermined voltage and when the boosted voltage does not exceed a predetermined voltage; and a switch including a first terminal and a second terminal connected to the output terminal of the boost circuit, which opens / closes the path connecting the first terminal and the second terminal based on the control signal.

[0010] The monitoring device according to at least one embodiment of the present invention includes a transmitting circuit, the transmitting circuit including an input terminal connected to a second terminal of the switch, and transmitting a monitoring signal including identification information of the thermal battery when receiving a voltage at the same node as the output terminal of the boost circuit via the switch, wherein the predetermined voltage is set to be above the minimum voltage at which the transmitting circuit can transmit the monitoring signal.

[0011] The monitoring device of at least one embodiment of the present invention, wherein the transmitting circuit is configured to wirelessly transmit the monitoring signal including the identification information of the thermal battery.

[0012] The monitoring device of at least one embodiment of the present invention, wherein the energy storage element has a capacitance value capable of storing enough power to enable the transmitting circuit to transmit the monitoring signal once.

[0013] At least one embodiment of the present invention provides a monitoring system that transmits a signal from a monitoring device to a receiving device that receives a monitoring signal including identification information of a thermal battery. The monitoring device is mounted on a monitored object and uses a thermal battery having a thermal power generation element that outputs a voltage corresponding to the temperature difference between the temperature of the atmosphere surrounding the monitored object and the temperature of the contact portion of the monitored object as a sensor. The monitored object is monitored based on the voltage corresponding to the temperature difference. The monitoring system includes a monitoring device comprising: a boost circuit, including an input terminal receiving voltage from the thermal battery and an output terminal outputting a boosted voltage obtained by boosting the voltage input from the input terminal; a power storage element connected to the output terminal of the boost circuit and storing power supplied from the thermal battery, which serves as the sensor, and boosted by the boost circuit; a voltage detection circuit that detects the boosted voltage and outputs a control signal from its output terminal, the control signal including signal levels corresponding to when the boosted voltage exceeds a predetermined voltage and when the boosted voltage does not exceed a predetermined voltage; and a transmitting circuit connected to the output terminal of the boost circuit and the input terminal of the voltage detection circuit via a switch that controls the opening and closing based on the control signal.

[0014] At least one embodiment of the damage assessment system of the present invention sends a monitoring signal including identification information of a thermal battery from a monitoring device to an assessment device for assessing the damage condition of a monitored object. The monitoring device is mounted on the monitored object and uses a thermal battery having a thermal power generation element that outputs a voltage corresponding to the temperature difference between the temperature of the atmosphere surrounding the monitored object and the temperature of the contact portion of the monitored object as a sensor. The monitored object is monitored based on the voltage corresponding to the temperature difference. The damage assessment system includes a monitoring device comprising: a boost circuit, including an input terminal receiving the voltage from the thermal battery and an output terminal boosting the voltage input from the input terminal. The system includes: an output terminal for the boosted voltage; an energy storage element connected to the output terminal of the boost circuit and storing the power supplied from the thermal battery (which serves as the sensor) and boosted by the boost circuit; a voltage detection circuit that detects the boosted voltage and outputs a control signal, the control signal including signal levels corresponding to when the boosted voltage exceeds a specified voltage and when the boosted voltage does not exceed a specified voltage; and a transmission circuit connected to the voltage detection circuit via a switch that controls the opening and closing based on the control signal and transmitting a signal to an evaluation device, the evaluation device evaluating the damage status of the monitored object based on a monitoring signal including the identification information of the thermal battery.

[0015] The damage assessment system of at least one embodiment of the present invention includes the assessment device, the assessment device comprising: a receiving unit for receiving the monitoring signal transmitted from the transmitting circuit; an assessment unit for inferring the voltage corresponding to the temperature difference based on the relationship between the time interval of the receiving unit receiving the monitoring signal and the voltage corresponding to the temperature difference, and assessing the damage status of the monitored object; and a control unit for controlling the receiving unit and the assessment unit.

[0016] The damage assessment system of at least one embodiment of the present invention includes a thermal battery comprising: a first thermal power generation element installed at a first location of the monitored object; and a second thermal power generation element installed at a second location different from the first location and in contact with the monitored object, and connected in series with the first thermal power generation element.

[0017] [The effects of the invention]

[0018] This invention enables continuous monitoring of objects without batteries and without maintenance, even with small battery capacity. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating a structural example of a monitoring device and monitoring system according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram showing an example of the structure of a thermal battery, which serves as the sensor for the monitoring device in this embodiment.

[0021] Figure 3 This is an explanatory diagram showing the power generation characteristics (power output relative to temperature difference) of the thermoelectric elements included in a thermal battery.

[0022] Figure 4 This is an explanatory diagram showing the boost characteristics (boost time relative to the generated voltage) of the boost circuit included in the monitoring device of this embodiment.

[0023] Figure 5 This is a schematic diagram illustrating a structural example of the damage assessment system of this embodiment.

[0024] Figure 6 This is a schematic diagram illustrating an application example of the damage assessment system of this embodiment.

[0025] Explanation of icon numbers

[0026] 10: Monitoring device

[0027] 11: Boost circuit

[0028] 12: Energy storage components

[0029] 13: Voltage detection circuit

[0030] 14: Switch

[0031] 15: Transmitting circuit

[0032] 20: Thermal battery

[0033] 21, 22: Thermoelectric elements

[0034] 30: Receiving device

[0035] 300: Evaluation device

[0036] 301: Receiving Department

[0037] 302: Control Department

[0038] 303: Assessment Department

[0039] 50: Monitoring System

[0040] 60: Damage Assessment System Detailed Implementation

[0041] Hereinafter, the monitoring device, monitoring system, and damage assessment system of the present invention will be described with reference to the accompanying drawings.

[0042] Figure 1 This is a schematic diagram showing a structural example of the monitoring device 10 and the monitoring system 50, which are examples of the monitoring devices and monitoring systems in this embodiment.

[0043] The monitoring system 50 comprises at least one monitoring device 10 and a receiving device 30 that is communicatively connected to the monitoring device 10.

[0044] The monitoring device 10 includes a boost circuit 11, an energy storage element 12, a voltage detection circuit 13, a switch 14, and a transmitting circuit 15, and is configured to be connected to the thermal battery 20. Here, the connection point between the thermal battery 20 and the monitoring device 10 is referred to as the input node 101.

[0045] The boost circuit 11 includes an input terminal 111, which is the same node as the input node 101, and an output terminal 112. The energy storage element 12 includes a first terminal connected to the output terminal 112, and a second terminal connected to the node, namely the GND terminal 2, which supplies ground voltage GND as an example of the power supply voltage.

[0046] The voltage detection circuit 13 includes: an input terminal 131, and a node N1 connected to the first end of the energy storage element 12 as the connection point of the output terminal 112; and an output terminal 132, which outputs a control signal, the control signal including a signal level corresponding to whether the boost voltage supplied to the input terminal 131 exceeds a specified voltage.

[0047] Switch 14 includes a first terminal and a second terminal connected to output terminal 112, and a control terminal connected to output terminal 132. Based on the signal level of the control signal, the first terminal and the second terminal are switched (controlled on / off) to an open state (open state) and a short-circuit state (closed state). In the following description, the first terminal and the second terminal of switch 14 will be referred to simply as the two terminals.

[0048] The transmitting circuit 15 is a circuit capable of communicating monitoring signals to an external part of the monitoring device 10, such as the receiving device 30. The transmitting circuit 15 includes an input terminal 151 connected to the second terminal of the switch 14. For example, the transmitting circuit 15, capable of wireless transmission, wirelessly transmits monitoring signals to the receiving device 30 external to the monitoring device 10.

[0049] Figure 2 This is a schematic diagram showing a structural example of the thermal battery 20.

[0050] Figure 3 This is an explanatory diagram showing the power generation characteristics (power output relative to temperature difference) of the thermal power generation elements 21 and 22 of the thermal battery 20, with the horizontal axis representing the temperature difference T [°C] and the vertical axis representing the power generation voltage Vout [V].

[0051] The thermal battery 20, which serves as a sensor and is connected to the monitoring device 10, is configured, for example, to have at least two thermal power generation elements 21 and 22. Thermal power generation elements 21 and 22 are elements that connect a p-type semiconductor element and an n-type semiconductor element in series, and generate a voltage proportional to the temperature difference between the surface at the high temperature and the surface at the low temperature (see reference). Figure 3 ).

[0052] Figure 2 The illustrated thermal battery 20 connects two thermoelectric power generation elements 21 and 22 in series via a connecting conductor 23. The connecting conductor 23 is any object capable of electrically connecting the thermoelectric power generation elements 21 and 22, i.e., a conductor. However, if the ease of installation of the thermoelectric power generation elements 21 and 22 is important, a conductor with appropriate flexibility and length is preferred.

[0053] Next, the function and effect of the monitoring device 10 and the monitoring system 50 will be explained.

[0054] The thermal power generation elements 21 and 22 constituting the thermal battery 20 generate electricity proportionally to the temperature difference between the surface mounted on the monitored object (hereinafter referred to as the "mounted surface") and the surface not mounted on the monitored object, i.e., the surface exposed to the atmosphere surrounding the thermal power generation elements 21 and 22 (hereinafter referred to as the "exposed surface"). Assuming the high-temperature side is set to 50 [°C] and the low-temperature side is set to 30 [°C], the temperature difference is 20 [°C]. Therefore, with a power generation capacity of 10 [mV / °C] for one thermal power generation element 21 (or 22), 200 [mV] of electricity is generated.

[0055] The power generated by the thermal battery 20 is supplied to the connected monitoring device 10 (more specifically, the boost circuit 11). The power generation voltage of the thermal battery 20, in the case of the example described, is a low voltage on the order of 100 mV / cell, for example, when the temperature difference is less than 10 °C, and therefore cannot directly drive the transmitting circuit 15. The boost circuit 11 boosts the voltage supplied from the input terminal 111 to a voltage (e.g., 2.0 V) that enables the transmitting circuit 15 to perform the desired operation. The energy supplied from the thermal battery 20 and boosted by the boost circuit 11 is stored in the energy storage element 12.

[0056] Figure 4 This is an explanatory diagram concerning the boost characteristics of the boost circuit 11 (boost time relative to the generated voltage), with the horizontal axis representing the generated voltage Vout [V] of the thermal battery 20 and the vertical axis representing the boost time t [seconds].

[0057] The boost time t [seconds] of the boost circuit 11 depends on the voltage supplied to the boost circuit 11, i.e., the power generation voltage Vout [V] of the thermal battery 20. For example... Figure 4 As shown, if the generator voltage Vout[V] is low, the boost time t[seconds] is long; if the generator voltage Vout[V] is high, the boost time t[seconds] is short.

[0058] The voltage detection circuit 13 detects whether the voltage at the output terminal 112 of the boost circuit 11, the first terminal of the energy storage element 12, and the input terminal 131 of the voltage detection circuit 13 (i.e., node N1) exceeds a predetermined voltage set as a threshold voltage, and outputs a control signal from the output terminal 132 including a signal level corresponding to the detection result. The threshold voltage of the voltage detection circuit 13 is, for example, set to a voltage above the amount of charge in the energy storage element 12 that provides enough energy to enable the transmitting circuit 15 to transmit a monitoring signal once.

[0059] When the voltage at node N1 is below the threshold voltage of voltage detection circuit 13, voltage detection circuit 13 outputs a control signal of a first signal level, such as a low level, from output terminal 132. On the other hand, when the supplied generated power begins to increase, the voltage at node N1 rises and eventually exceeds the threshold voltage of voltage detection circuit 13, a control signal of a second signal level, such as a high level, is output from output terminal 132.

[0060] For example, when a control signal of the first signal level is received at the control terminal, switch 14 disconnects the path connecting both ends of switch 14, and when a control signal of the second signal level is received at the control terminal, it closes the path connecting both ends. Switch 14 is in an open state, with its ends open, before the voltage at node N1 exceeds the threshold voltage of the voltage detection circuit 13, i.e., when a control signal of the first signal level is received at the control terminal. When the voltage at node N1 exceeds the threshold voltage of the voltage detection circuit 13, i.e., when a control signal of the second signal level is received at the control terminal, it becomes a closed state, with its ends short-circuited.

[0061] Therefore, when the voltage at node N1 rises and exceeds the threshold voltage of the voltage detection circuit 13, switch 14 changes from the open state to the closed state, and the input terminal 151 of the transmitting circuit 15 is short-circuited with node N1. In the transmitting circuit 15 short-circuited with node N1, a voltage capable of transmitting a monitoring signal to the external receiving device 30 is supplied to input terminal 151, thus transmitting the monitoring signal to the receiving device 30. The monitoring signal includes identification information that identifies the thermal battery 20 connected to the monitoring device 10.

[0062] Here, the voltage required for the transmitting circuit 15 to transmit a monitoring signal once will be explained. When the transmitting circuit 15 is configured as a wireless transmitting circuit capable of wireless communication, the wireless communication method used is arbitrary as long as it enables wireless communication between the monitoring device 10 and the receiving device 30. However, depending on the wireless communication method used, the voltage and energy required to transmit a monitoring signal once will differ; therefore, the capacitance value of the energy storage element 12 or the boost voltage of the boost circuit 11 is determined based on the wireless communication method used.

[0063] For example, comparing the use of Bluetooth Low Energy (BLE), which is suitable for short communication distances, with the use of LoRa WAN, which is suitable for longer communication distances than BLE, the LoRa WAN transmitting circuit 15 requires approximately 10 times the wireless communication energy compared to the BLE transmitting circuit 15. Therefore, the capacitance of the energy storage element 12 in the monitoring device 10, which includes the LoRa WAN transmitting circuit 15, is configured to be approximately 10 times greater than the capacitance of the energy storage element 12 in the monitoring device 10, which includes the BLE transmitting circuit 15.

[0064] The receiving device 30 receives monitoring signals from the monitoring device 10. Since the monitoring signals received by the receiving device 30 include identification information that can identify the thermal battery 20 connected to the monitoring device 10, even in a monitoring system 50 that includes n monitoring devices 10, the receiving device 30 can individually grasp the status of each of the n monitored objects.

[0065] Based on the above, even if the supplied power is small, the monitoring device 10 and the monitoring system 50 can be configured such that when the boost circuit 11 obtains a boost voltage that exceeds the voltage required to send a monitoring signal once relative to the power generated when the expected abnormality occurs, the monitoring signal can be sent to an external device such as the receiving device 30.

[0066] Based on the monitoring device 10 and monitoring system 50, by employing a thermal battery 20 that can function as both a power source and a sensor, a device and system unaffected by weather and time can be constructed compared to existing monitoring devices and systems that use solar cells as power sources. Furthermore, since maintenance such as surface cleaning is not required as with solar cells, the burden of power source inspection and maintenance can be reduced compared to existing monitoring devices and systems that use solar cells as power sources.

[0067] Furthermore, if the monitoring device 10 includes a storage element 12 connected at one end to the output terminal 112 of the boost circuit 11, energy will accumulate in the storage element 12 as long as the power supply is continuous even with intermittent power supply. Therefore, the minimum capacitance value of the storage element 12 can be reduced to a capacitance value sufficient to store enough power for the transmitting circuit 15 to transmit a monitoring signal. Thus, unlike existing monitoring devices and systems that use solar cells, it is not necessary to use a separate primary battery as an auxiliary power source or a large-capacity storage element such as an electrostatic double-layer capacitor. Therefore, a monitoring device 10 that is smaller than existing monitoring devices can be provided.

[0068] In the monitoring device 10 and the monitoring system 50, if the thermal battery 20 is configured with thermal power generation elements 21 and 22 connected in series, the power generation voltage can be increased compared to the case where only one element is present, and the interval between voltage boosting and transmission of the monitoring signal can be shortened. Furthermore, when configured with thermal power generation elements 21 and 22, monitoring operation can be continuous as long as one of the thermal power generation elements 21 or 22 generates electricity, thus enabling the monitoring device 10 to have strong resistance to sensor failures.

[0069] Furthermore, the monitoring device 10 and monitoring system 50 can be configured as an event-driven device and system that wirelessly transmits signals when an anomaly occurs in the monitored object (a temperature rise caused by heat generation). Additionally, since the thermal battery 20 serves as both a power source and a sensor, the monitoring device 10 and monitoring system 50 can continuously monitor the monitored object even without a battery, provided they are powered. In the monitoring device 10 and monitoring system 50, the greater the temperature difference, the shorter the time interval for transmitting monitoring signals; conversely, the smaller the temperature difference, the longer the time interval for transmitting monitoring signals.

[0070] Therefore, in the monitoring device 10 and the monitoring system 50, only the transmission time interval of the monitoring signal from the transmitting circuit 15, i.e., the reception time interval of the monitoring signal from the receiving device 30, needs to be monitored. It is not necessary to continuously monitor the temperature based on wirelessly transmitted data as in existing monitoring devices and systems. Therefore, the power consumption required for the operation of the monitoring device 10 and the monitoring system 50 can be suppressed, contributing to battery-free operation.

[0071] Furthermore, using a thermal battery 20, which generates electricity based on the temperature difference between the high-temperature and low-temperature sides, as a sensor is superior to using only a temperature sensor that measures the temperature of the contact portion. This is because it allows for consideration of temperature variations in the atmosphere surrounding the monitored object. For example, since changes in air temperature that occur with the seasons can be taken into account, anomalies in the monitored object can be detected more accurately.

[0072] Thus, according to the monitoring device 10 and the monitoring system 50, as long as the energy that can be stored to send a monitoring signal once is sufficient, even if the capacitance value of the energy storage element 12 is small, the monitoring object can be continuously monitored without batteries and without maintenance.

[0073] Next, the situation in which the monitoring system of this embodiment functions as a damage assessment system for assessing the damage status of the monitored object will be explained.

[0074] Figure 5 This is a schematic diagram showing the structure of a damage assessment system 60, which is an example of a damage assessment system in this embodiment.

[0075] The damage assessment system 60 is a form of the monitoring system 50, and is a form in which the receiving device 30 of the monitoring system 50 functions as an assessment device 300. That is, the damage assessment system 60 is composed of a monitoring device 10 and an assessment device 300, wherein the assessment device 300 has the function of receiving monitoring signals and assessing the damage status of the monitored object.

[0076] The evaluation device 300 is implemented, for example, by having hardware such as a computer capable of executing a program (hereinafter referred to as "PG") execute the evaluation PG 31 as software. When the receiving device 30 has a processor capable of executing the PG, the evaluation PG 31 is executed by the processor, and the receiving device 30, as hardware, simultaneously performs the functions of receiving monitoring signals and evaluating the damage status of the monitored object. That is, the evaluation PG 31 and the receiving device 30 work together, enabling the receiving device 30 to function as the evaluation device 300. The evaluation device 300 includes a receiving unit 301 for receiving monitoring signals, an evaluation unit 303 for evaluating the damage status of the monitored object, and a control unit 302 for controlling the receiving unit 301 and the evaluation unit 303.

[0077] The control unit 302 provides the monitoring signal received by the receiving unit 301 to the assessment unit 303, which assesses the damage status of the monitored object.

[0078] The evaluation unit 303 includes historical information on the received monitoring signals and information indicating the relationship between the time interval of receiving monitoring signals and the degree of damage corresponding to the resistance value of the monitored object. The evaluation unit 303 evaluates the damage status of the monitored object on which the thermoelectric power generation elements 21 and 22, which are installed as sensors, are based on the reception interval of the monitoring signals received from the receiving unit 301.

[0079] The time interval for receiving monitoring signals is equivalent to the time before the voltage of node N1 exceeds the threshold voltage of voltage detection circuit 13, i.e., the boost time based on boost circuit 11. Therefore, the greater the generated power supplied from thermal battery 20, the shorter the time interval for receiving monitoring signals; conversely, the smaller the generated power supplied from thermal battery 20, the longer the time interval for receiving monitoring signals.

[0080] Furthermore, the damage to a conductor is related to its resistance as follows: less damage results in less resistance, and more damage results in more resistance. Therefore, the greater the Joule heat generated during conduction, i.e., the higher the temperature of the contact area of ​​the monitored object, the greater the damage to the conductor can be assessed. Taking this relationship into account, the evaluation unit 303 assesses the damage to the monitored object as small when the temperature difference corresponding to the voltages of the thermoelectric power generation elements 21 and 22 installed on the monitored object is small, and assesses the damage to the monitored object as large when the temperature difference corresponding to the voltages of the thermoelectric power generation elements 21 and 22 is large.

[0081] Here, the information relating the time interval for receiving monitoring signals to the degree of damage to the monitored object can be obtained based on information relating the time interval for receiving monitoring signals to the voltage corresponding to the temperature difference between the thermoelectric power generation elements 21 and 22, and information relating the voltage corresponding to the temperature difference between the thermoelectric power generation elements 21 and 22 installed on the monitored object to the degree of damage to the monitored object. Furthermore, the type of information relating the time interval for receiving monitoring signals to the degree of damage to the monitored object is arbitrary, as long as the degree of damage to the monitored object as the final result can be obtained.

[0082] If we describe the evaluation device 300 from a process perspective, the process by which the evaluation device 300 evaluates the damage status of the monitored object (hereinafter referred to as the "damage evaluation process") includes the following steps: receiving a monitoring signal from the monitoring device 10; and determining the time interval for receiving the monitoring signal, and evaluating the damage status of the monitored object based on information representing the relationship between the time interval for receiving the monitoring signal and the degree of damage to the monitored object. In other words, the evaluation PG 31 is a PG that enables hardware capable of executing programs to perform the damage evaluation process.

[0083] Next, an application example of the damage assessment system 60 will be explained.

[0084] Figure 6 This is a schematic diagram showing an application example of the damage assessment system 60, in which a monitoring device 10 and thermoelectric power generation elements 21 and 22 as sensors are installed on the wire 80, which is the object of damage assessment.

[0085] according to Figure 6The wire 80 is constructed by compressing two wires 81 and 82 (for example) into a sleeve 83, which serves as a metal connecting tube, and mechanically and electrically connecting the wires 81 and 82 (crimping). In the wire 80, where the wires 81 and 82 are mechanically and electrically connected into one by crimping, the sleeve 83, which serves as the connecting part, is more prone to breakage than other parts. Therefore, by installing the thermoelectric element 21 and thermoelectric element 22, which serve as sensors, at different positions (first position and second position) within the sleeve 83, which serves as the connecting part, the temperature of the connecting part can be estimated, and the degree of damage to the wire 80 can be assessed based on the estimated temperature.

[0086] exist Figure 6 In the illustrated monitoring object, because current flows in the wire 80, when the damage to the sleeve 83 worsens for some reason, its resistance increases, resulting in increased Joule heating. This increased Joule heating causes the temperature of the sleeve 83 to rise, thus raising the temperature on the high-temperature side of the thermoelectric element 21 and thermoelectric element 22, which is the mounting surface of the sleeve 83. The resulting increase in temperature on the high-temperature side widens the temperature difference with the exposed surface, which is the low-temperature side, thus increasing the generated voltage.

[0087] According to the damage assessment system 60, which mounts thermoelectric elements 21 and 22 on the sleeve 83, the temperature of the sleeve 83, which serves as the connection point of the wire 80, can be continuously monitored. Therefore, changes in Joule heating generated in the sleeve 83, i.e., changes in the resistance of the connection point, can be detected at an early stage. Thus, even if an abnormality occurs in the connection point of the wire 80 that is being monitored, the abnormality can be detected early, and the detected abnormal part can be repaired efficiently.

[0088] Based on the monitoring device 10 and the damage assessment system 60, and considering the effectiveness of the monitoring device 10 and the monitoring system 50, if the monitored object is a conductor carrying electricity such as an electric wire 80, the increase in resistance value as damage progresses can be interpreted as a temperature rise. Therefore, the damage status of the monitored object can be assessed based on information indicating the relationship between the time interval of receiving monitoring signals and the degree of damage to the monitored object. In other words, according to the monitoring device 10 and the damage assessment system 60, even when the capacitance value of the energy storage element 12 is small, monitoring of the monitored object and assessment of its damage status can be performed continuously without a battery and in a maintenance-free manner.

[0089] Furthermore, the present invention is not limited to the described embodiments. In the implementation stage, it can be implemented in various forms in addition to the described embodiments, and various omissions, additions, substitutions or changes can be made within the scope of the spirit of the invention.

[0090] For example, although the monitoring device 10 including the transmitting circuit 15 has been described, the monitoring device 10 may also be configured to omit the transmitting circuit 15, and the input terminal 151 of the transmitting circuit 15 can be used as the output node of the monitoring device 10 to output the monitoring signal. The thermal battery 20 only needs to include at least one thermal power generation element 21 (or 22), and is not limited to two. That is, it can be used even if the monitoring device 10 has two or more monitoring points.

[0091] In the damage assessment system 60, although the example given is that the assessment device 300 is the same as the receiving device 30, the assessment device 300 may also be configured as a different device from the receiving device 30.

[0092] The voltage detection circuit 13 may also have a hysteresis function. Additionally, the monitoring device 10 may also have the following function: after the voltage detection circuit 13 detects that the voltage of node N1 exceeds the threshold voltage of the voltage detection circuit 13, it will keep the switch 14 in a closed state for a certain period of time (until the communication ends). The function of keeping the switch 14 in a closed state for a certain period of time can be provided by having the voltage detection circuit 13 have this function, or it can be provided by adding circuitry with the aforementioned function.

[0093] These embodiments and their variations are included within the scope or spirit of the invention, as well as within the scope of the invention as described in the claims and their equivalents.

Claims

1. A monitoring device, installed on a monitored object, using a thermoelectric cell having a thermoelectric element that outputs a voltage corresponding to the temperature difference between the temperature of the atmosphere surrounding the monitored object and the temperature of a contact portion in contact with the monitored object as a sensor, and monitoring the monitored object based on the voltage corresponding to the temperature difference, the monitoring device being characterized by comprising: A boost circuit includes an input terminal that receives a voltage from the thermal battery and an output terminal that outputs a boosted voltage obtained by boosting the voltage input from the input terminal. An energy storage element is connected to the output terminal of the boost circuit and stores the power supplied from the thermal battery, which serves as the sensor, and boosted by the boost circuit. A voltage detection circuit detects the boost voltage and outputs a control signal from its output terminal. The control signal includes signal levels corresponding to when the boost voltage exceeds a specified voltage and when the boost voltage does not exceed a specified voltage, respectively. as well as A switch, including a first terminal and a second terminal connected to the output terminal of the boost circuit, opens / closes the path connecting the first terminal and the second terminal based on the control signal.

2. The monitoring device according to claim 1, comprising a transmitting circuit, the transmitting circuit including an input terminal connected to a second terminal of the switch, wherein when a voltage at the same node as the output terminal of the boost circuit is received via the switch, a monitoring signal including identification information of the thermal battery is transmitted. The specified voltage is set to be above the minimum voltage at which the transmitting circuit can transmit the monitoring signal.

3. The monitoring device according to claim 2, wherein, The transmitting circuit is configured to wirelessly transmit the monitoring signal, which includes the identification information of the thermal battery.

4. The monitoring device according to claim 2, wherein, The energy storage element has a capacitance value capable of storing enough power to enable the transmitting circuit to transmit the monitoring signal once.

5. A monitoring system that transmits a signal from a monitoring device to a receiving device that receives a monitoring signal including identification information of a thermal battery, the monitoring device being mounted on a monitored object, the thermal battery having a thermal power generation element that outputs a voltage corresponding to the temperature difference between the temperature of the atmosphere surrounding the monitored object and the temperature of the contact portion of the monitored object as a sensor, and monitoring the monitored object based on the voltage corresponding to the temperature difference, the monitoring system being characterized in that... The device includes a monitoring apparatus comprising: a boost circuit, including an input terminal receiving voltage from the thermal battery and an output terminal outputting a boosted voltage obtained by boosting the voltage input from the input terminal; a storage element connected to the output terminal of the boost circuit and storing power supplied from the thermal battery (which serves as the sensor) and boosted by the boost circuit; a voltage detection circuit detecting the boosted voltage and outputting a control signal, the control signal including signal levels corresponding to when the boosted voltage exceeds a predetermined voltage and when the boosted voltage does not exceed a predetermined voltage; and a transmitting circuit connected to the output terminal of the boost circuit and the input terminal of the voltage detection circuit via a switch that performs on / off control based on the control signal.

6. A damage assessment system, wherein a monitoring device sends a monitoring signal including identification information of a thermal battery from a monitoring device to an assessment device for assessing the damage condition of a monitored object, the monitoring device being mounted on the monitored object, and the thermal battery having a thermal power generation element that outputs a voltage corresponding to the temperature difference between the temperature of the atmosphere surrounding the monitored object and the temperature of the contact portion of the monitored object as a sensor, and the monitored object is monitored based on the voltage corresponding to the temperature difference, the damage assessment system being characterized in that... The device includes a monitoring apparatus comprising: a boost circuit, including an input terminal for receiving voltage from the thermal battery and an output terminal for outputting a boosted voltage obtained by boosting the voltage input from the input terminal; a storage element connected to the output terminal of the boost circuit and storing power supplied from the thermal battery (which serves as the sensor) and boosted by the boost circuit; a voltage detection circuit for detecting the boosted voltage and outputting a control signal, the control signal including signal levels corresponding to when the boosted voltage exceeds a predetermined voltage and when the boosted voltage does not exceed a predetermined voltage; and a transmitting circuit connected to the voltage detection circuit via a switch controlled by the control signal and transmitting a signal to an evaluation device, the evaluation device evaluating the damage status of the monitored object based on the monitoring signal including identification information of the thermal battery.

7. The damage assessment system according to claim 6, characterized in that, The evaluation device includes: The receiving unit receives the monitoring signal transmitted from the transmitting circuit; The evaluation unit, based on the relationship between the time interval of the receiving unit receiving the monitoring signal and the voltage corresponding to the temperature difference, infers the voltage corresponding to the temperature difference and evaluates the damage status of the monitored object; and The control unit controls the receiving unit and the evaluation unit.

8. The damage assessment system according to claim 6 or 7, wherein, The thermal battery has the following characteristics: A first thermal power generation element is installed at a first location on the monitored object; as well as The second thermoelectric element is installed at a second location, different from the first location and in contact with the monitored object, and is connected in series with the first thermoelectric element.

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