Information processing system and information processing method

Abstract

One embodiment of the present invention provides an information processing system. This information processing system comprises a thermoelectric conversion unit and a signal processing unit. The thermoelectric conversion unit is configured so as to generate a thermal gradient by exchanging heat with a device and is configured so as to generate thermoelectric power on the basis of the thermal gradient. The signal processing unit comprises an acquiring unit and a detection unit. The acquiring unit is configured so as to acquire the thermoelectric power. The detection unit is configured so as to detect, on the basis of the thermoelectric power, an abnormal operation of the device accompanied by heat generation.

Description

Information processing system and information processing method

[0001] The present invention relates to an information processing system and an information processing method.

[0002] Patent Document 1 discloses a technique for estimating a temperature corresponding to the internal resistance of an electric storage element.

[0003] The energy storage system described in Patent Document 1 includes an energy storage element that performs charging and discharging, a temperature sensor for acquiring the temperature outside the energy storage element, and a controller that calculates a reference point temperature that indicates a temperature corresponding to the internal resistance of the energy storage element using the temperature outside the energy storage element and an equation that represents heat transfer. When resuming charging and discharging of the energy storage element, the controller determines whether temperature variations inside the energy storage element have been resolved. If the temperature variations have been resolved, the controller uses the surface temperature of the energy storage element as the temperature of the reference point, and if the temperature variations have not been resolved, the controller calculates the temperature of the reference point.

[0004] JP 2013-118056 A

[0005] When using a temperature sensor to detect abnormalities or control equipment, the temperature change of the temperature sensor itself is necessary. However, because the temperature sensor itself has heat capacity, the temperature change of the temperature sensor tends to lag behind the temperature change of the equipment depending on the heat capacity.

[0006] According to one aspect of the present invention, there is provided an information processing system. The information processing system includes a thermoelectric conversion unit and a signal processing unit. The thermoelectric conversion unit is configured to generate a temperature gradient by heat exchange with an equipment and to generate a thermoelectromotive force based on the temperature gradient. The signal processing unit includes an acquisition unit and a detection unit. The acquisition unit is configured to acquire the thermoelectromotive force. The detection unit is configured to detect abnormal operation of the equipment that generates heat based on the thermoelectromotive force.

[0007] With this configuration, changes in temperature gradient due to heat generation by the equipment occur in a shorter time than changes in temperature due to heat generation by the equipment, making it possible to detect or control abnormalities in the equipment with higher sensitivity than conventional methods.

[0008] 1 is a diagram illustrating an overview of an information processing system 1. It is a diagram illustrating an example of the configuration of a signal processing circuit 35. It is a perspective view showing an example of the structure of a power storage unit BU. It is a plan view of one of the power storage units BU illustrated in FIG. 3 when viewed from a first direction D1. It is a side view of one of the power storage units BU illustrated in FIG. 3 when viewed from a third direction D3. It is a block diagram showing a hardware configuration of an information processing device 4. It is a diagram illustrating an example of a functional unit included in a processor 43. It is an activity diagram showing an example of the flow of first information processing executed in the information processing system 1. It is an activity diagram showing an example of the flow of second information processing executed in the information processing system 1. It is an activity diagram showing an example of the flow of third information processing executed in the information processing system 1. It is a cross-sectional view of a power storage device 2 and a thermoelectric conversion unit 31 in contact with the power storage device 2, taken along a plane perpendicular to the third direction D3. It is a diagram illustrating an example of a thermal circuit model M. It is a cross-sectional view of the power storage device 2, etc., taken along a plane perpendicular to the third direction D3, in a case where the thermoelectric conversion unit 31 is in contact with the power storage device 2 via a temperature adjustment element 6. It is a diagram illustrating another example of the signal processing circuit 35. 10 is a diagram showing an example of a signal processing system 3 that does not include a first heat conducting section 33. FIG. 11 is a diagram showing an example of an attachment mode of a thermoelectric conversion section 31. FIG.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other.

[0010] Incidentally, the program for realizing the software appearing in this embodiment may be provided as a non-transitory computer-readable recording medium, or may be provided so as to be downloadable from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client terminal (so-called cloud computing).

[0011] In this embodiment, the term "unit" may include, for example, a combination of hardware resources implemented by a circuit in the broad sense and software information processing that can be specifically realized by these hardware resources. In addition, various types of information are handled in this embodiment, and this information may be represented by, for example, physical values ​​of signal values ​​representing voltages and currents, high and low signal values ​​as a binary bit set consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations may be performed on a circuit in the broad sense.

[0012] Furthermore, a circuit in the broad sense is a circuit realized by at least an appropriate combination of a circuit, circuitry, a processor, a memory, etc. That is, it includes an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)), etc.

[0013] 1. Overview of Information Processing System 1 This section describes an overview of the information processing system 1. FIG.

[0014] 1 and 2 , the information processing system 1 includes a driving device M1 and a power storage system BS. The driving device M1 is configured to be driven by power output from the power storage system BS, and examples of the driving device M1 include a motor, a light, and a computer. The driving device M1 transmits a required power P necessary for its own operation to the outside. The power storage system BS is connected to the driving device M1 through a power converter (not shown), and can output power according to the required power P by controlling the power converter. The power storage system BS includes at least one power storage unit BU (three or more in this embodiment).

[0015] <Power storage unit BU> The power storage unit BU is configured to supply power to the driving equipment M1 in accordance with the required power P transmitted from the driving equipment M1. The power storage units BU are connected in series with each other and include, for example, a power storage device 2 as a device and a signal processing system 3. The power storage units BU may be connected in any manner, and may be connected in parallel.

[0016] <Power Storage Device 2> The power storage device 2 is configured to be able to charge and discharge power to and from the movable device M1 and includes, for example, a housing 21 and a power storage unit 22 housed inside the housing 21. The housing 21 is configured to conduct heat generated by the power storage unit 22 to at least a portion of its surface and is formed using a thermally conductive material such as metal. Specific aspects of the housing 21 will be described later. The power storage unit 22 is configured to generate an electromotive force V, and examples thereof include a lead-acid battery, a nickel-cadmium battery, a lithium-ion battery, and an air battery. In particular, lithium-ion batteries include iron phosphate-based, iron titanate-based, ternary-based, manganese-based, nickel-based, cobalt-based, NCA (nickel-cobalt-aluminum)-based, and lithium polymer-based batteries. The power storage device 2 may be any one of these or a combination of multiple elements, and is not particularly limited. The power storage device 2 is configured to generate heat depending on the operating state of the power storage device 2. For example, the power storage device 2 generates heat such that the amount of heat generated increases as the amount of discharge or charge per unit time increases.

[0017] <Signal Processing System 3> The signal processing system 3 is configured to process a signal including information regarding the state of the power storage device 2. The signal processing system 3 includes a thermoelectric conversion unit 31, a heat bath 32, a first heat conduction unit 33, a second heat conduction unit 34, a signal processing circuit 35, and a switch 36, and at least a part of the signal processing system 3 functions as a signal processing unit.

[0018] <Thermoelectric conversion unit 31> The thermoelectric conversion unit 31 is configured to generate a temperature gradient J through heat exchange with the power storage device 2, and to generate a thermoelectromotive force E based on the temperature gradient J. In particular, the thermoelectric conversion unit 31 is configured to generate a thermoelectromotive force E in accordance with the temperature gradient J generated in the thermoelectric conversion unit 31 through heat exchange with the power storage device 2. As a result, in this embodiment, the thermoelectric conversion unit 31 can function as a heat flow sensor that can detect a heat flow due to heat exchange with the power storage device 2. The thermoelectric conversion unit 31 will be described in detail later.

[0019] <Heat bath 32> The heat bath 32 is maintained at a predetermined reference temperature Tb. The reference temperature Tb is a temperature that serves as a reference for the temperature gradient J generated in the thermoelectric conversion unit 31. The specific configuration of the heat bath 32 is arbitrary, but examples include a housing that houses the power storage unit BU or a housing of the driving device M1, whose temperature is maintained at approximately the outside temperature by heat exchange with the outside air, and a member with a sufficiently large heat capacity compared to the housing 21, such as a metal bath or a salt bath.

[0020] <First heat conducting portion 33> The first heat conducting portion 33 connects the power storage device 2 (the housing 21 in this embodiment) and the thermoelectric conversion portion 31, and is formed of a heat conducting material such as metal. Heat exchange occurs between the housing 21 and the thermoelectric conversion portion 31 via the first heat conducting portion 33. As a result, a temperature gradient J occurs within the thermoelectric conversion portion 31 in a direction from the first heat conducting portion 33 toward the thermoelectric conversion portion 31. With this configuration, heat exchange between the power storage device 2 and the thermoelectric conversion portion 31 occurs via the first heat conducting portion 33, which makes it easier to reduce variations in thermoelectromotive force E due to differences in the heat generation position of the power storage device 2.

[0021] <Second Heat Conduction Unit 34> The second heat conduction unit 34 is connected to the heat bath 32 and configured to maintain the temperature of the second region 312 at approximately the reference temperature Tb. This configuration makes it easier to more accurately grasp the temperature gradient J of the thermoelectric conversion unit 31. Like the first heat conduction unit 33, the second heat conduction unit 34 is formed of a thermally conductive material such as metal. Heat exchange occurs between the thermoelectric conversion unit 31 and the heat bath 32 via the second heat conduction unit 34. In this embodiment, heat exchange occurs between the housing 21 and the thermoelectric conversion unit 31, and between the thermoelectric conversion unit 31 and the heat bath 32. This configuration stabilizes the operating temperature of the thermoelectric conversion unit 31, thereby improving the accuracy of detecting the heat generation state of the power storage device 2. The heat bath 32 is an example of a temperature adjustment unit that can adjust the temperature of the second heat conduction unit 34.

[0022] <Signal Processing Circuit 35> The signal processing circuit 35 is configured to acquire the thermoelectromotive force E generated by the thermoelectric conversion unit 31 and control the power storage device 2 etc. in accordance with the thermoelectromotive force E. The thermoelectromotive force E is an example of a first signal caused by the thermoelectromotive force E.

[0023] Here, a description will be given of an example configuration of the signal processing circuit 35. Fig. 2 is a diagram showing an example configuration of the signal processing circuit 35. As shown in Fig. 2, the signal processing circuit 35 includes a comparison unit 351 and an AC / DC converter 352.

[0024] <Comparing Unit 351> The comparing unit 351 is configured to compare the thermoelectromotive force E of the thermoelectric conversion unit 31 with a threshold voltage Vt1 as a predetermined reference value. In this embodiment, the comparing unit 351 is configured with an operational amplifier, and its inverting input terminal is connected to a reference power supply that outputs the threshold voltage Vt1, and its non-inverting input terminal is connected to the thermoelectric conversion unit 31. Therefore, when the thermoelectromotive force E output from the thermoelectric conversion unit 31 exceeds the threshold voltage Vt1, the comparing unit 351 outputs an analog voltage signal corresponding to the difference between the thermoelectromotive force E and the threshold voltage Vt1.

[0025] <AC / DC Converter 352> The AC / DC converter 352 is connected to the output terminal of the comparison unit 351. The AC / DC converter 352 is configured to convert the analog voltage signal output from the comparison unit 351 into a digital signal. The digital signal is output to, for example, the information processing device 4.

[0026] <Switch 36> The switch 36 is configured to allow charging and discharging of the power storage device 2 when in an on state, and to restrict, more specifically, stop, charging and discharging of the power storage device 2 when in an off state. The specific form of the switch 36 is arbitrary. For example, if the switch 36 is a single-pole, single-throw type, turning the switch 36 off restricts charging and discharging of all power storage devices 2. Furthermore, if the switch 36 is a single-pole, double-throw type, turning the switch 36 off connects the switch 36 to a redundant circuit that bypasses the power storage device 2 corresponding to that switch 36, and restricts charging and discharging of the corresponding power storage device 2 alone.

[0027] <Information Processing Device 4> In the present embodiment, one of the signal processing systems 3 further includes an information processing device 4. The information processing device 4 is configured to cross-sectionally control each of the signal processing systems 3, and functions as, for example, a battery management system (BMS). Furthermore, the information processing device 4 of the present embodiment is configured to be able to control a driving device M1 as a second device that is a device other than the power storage device 2.

[0028] 2. Example of the Structure of the Energy Storage Unit BU In this section, an example of the structure of the above-mentioned energy storage unit BU will be described. Fig. 3 is a perspective view showing an example of the structure of the energy storage unit BU. Fig. 4 is a plan view of one of the energy storage units BU shown in Fig. 3 when viewed from a first direction D1. Fig. 5 is a side view of one of the energy storage units BU shown in Fig. 3 when viewed from a third direction D3.

[0029] As shown in FIG. 3 , each of the energy storage units BU is configured as a flat plate in a plane whose normal extends in a first direction D1, and is stacked on top of each other in the first direction D1 to form a single assembly. The first direction D1 can also be referred to as the stacking direction. For ease of explanation, various wiring extending from the energy storage units BU is not shown. Also, for ease of explanation, two directions perpendicular to the first direction D1 are referred to as a second direction D2 and a third direction D3, respectively. The second direction D2 and the third direction D3 are perpendicular to each other.

[0030] As shown in FIGS. 3 to 5 , the housing 21 of the power storage device 2 is formed as a flat rectangular parallelepiped whose normal extends in a first direction D1, and its thickness direction is parallel to the first direction D1. The long sides of the housing 21 extend along a second direction D2, and the short sides of the housing 21 extend along a third direction D3. In this embodiment, the second direction D2 can be referred to as the long side direction, and the third direction D3 can be referred to as the short side direction. The power storage device 2 generates heat due to operations such as charging and discharging, or an abnormality such as a failure of the power storage unit 22, and a heat source Q may be generated inside the housing 21. In this embodiment, a case where the heat source Q is generated in the center of the power storage device 2 will be described. Note that the location of the heat source Q is not limited to the center and may be arbitrary. For example, the heat source Q may be located on the surface or inside of the power storage device 2, or at an end of the power storage device.

[0031] The first heat conducting portion 33 is formed in a flat plate shape with a normal extending in the first direction D1 , and includes a main surface portion 331 and a protrusion portion 332 .

[0032] <Principal Surface Portion 331> Like the housing 21, the principal surface portion 331 is formed in a rectangular flat plate shape, and its thickness direction is parallel to the first direction D1. The long sides of the principal surface portion 331 extend along the second direction D2, and the short sides of the principal surface portion 331 extend along the third direction D3. The principal surface portion 331 is in contact with the housing 21 in the first direction D1, so that heat generated from the heat source Q is conducted through the housing 21 to the surface of the housing 21 and then from the surface of the housing 21 to the principal surface portion 331.

[0033] When one of the storage units BU is viewed in a plane from the first direction D1, the outer edge of the main surface portion 331 in a plane perpendicular to the first direction D1 is formed so as to be included within the outer edge of the main surface portion 331 in the plane perpendicular to the first direction D1.

[0034] <Protrusion 332> As shown in FIG. 4 , the protrusion 332 is configured to protrude from the power storage device 2 when the power storage device 2 is viewed in a plan view from a predetermined first direction D1, and extends in a second direction D2 from a portion of the outer edge of the main surface portion 331. Therefore, even when multiple power storage units BU are stacked, the protrusion 332 is configured not to be clamped by the housing 21. This configuration makes it easier to measure the thermoelectromotive force E of the thermoelectric conversion unit 31, thereby improving the flexibility of the arrangement of the power storage devices 2 and the like. The protrusion 332 has a rectangular flat plate shape whose thickness direction extends along the first direction D1 and is integrally formed flush with the main surface portion 331. Note that the shape of the protrusion 332 is arbitrary and is not limited thereto. Furthermore, the protrusions 332 of different power storage units BU may be configured not to overlap with each other when the power storage device 2 is viewed in a plan view from the first direction D1. With this configuration, by ensuring space near the protruding portion 332 in the first direction D1, it is possible to promote heat convection near the protruding portion 332. Meanwhile, the protruding portions 332 of different energy storage units BU may be configured to overlap with each other when the energy storage device 2 is viewed in a plan view from the first direction D1. With this configuration, it is possible to make the assembly formed of multiple energy storage units BU more compact.

[0035] <Thermoelectric Conversion Unit 31> The thermoelectric conversion unit 31 is configured to generate a thermoelectromotive force E including a component generated in a direction different from the temperature gradient J. This configuration facilitates measurement of the thermoelectromotive force E from a direction different from the temperature gradient J, thereby reducing the amount of wiring between the power storage device 2 and the thermoelectric conversion unit 31. This reduces the need for wiring between the power storage device 2 and the thermoelectric conversion unit 31. This reduces the sensitivity to the temperature gradient J. In this embodiment, the temperature gradient J is generated along a first direction D1, and the thermoelectromotive force E includes a component generated in a second direction D2 perpendicular to the first direction D1. The thermoelectric conversion unit 31 is configured so that the thermoelectromotive force E changes in response to a temperature change due to heat generation on the surface of the power storage device 2 (e.g., a region of the surface of the housing 21 that is in contact with the thermoelectric conversion unit 31). The thermoelectric mechanism for generating the thermoelectromotive force E is arbitrary, but can be realized, for example, by the anomalous Nernst effect. Due to the anomalous Nernst effect, the thermoelectric conversion unit 31 generates a thermoelectromotive force E in a direction perpendicular to the temperature gradient J and the direction characterizing the magnetic structure, due to a magnetic structure characterized in a direction perpendicular to the temperature gradient J. In other words, the anomalous Nernst effect is expressed by a quantity that depends on a physical variable corresponding to a magnetic field among the off-diagonal components of the thermoelectric tensor of the thermoelectric conversion unit 31. The thermoelectromotive force E is antisymmetric with respect to the magnetic field, symmetric with respect to the in-plane component perpendicular to the first direction D1 of the temperature gradient J, and antisymmetric with respect to the perpendicular component parallel to the first direction D1.

[0036] Examples of compositions capable of exhibiting such an anomalous Nernst effect include, but are not limited to, Mn3Sn, Mn3Ge, Mn3Ga, Co2MnGa, Fe3Al, Fe3Ga, Fe3Sn2, FeGa, L1_0-type FePt, L1_0-type FePd, L1_0-type MnGa, D0_22-type Mn2Ga, SmCo5, Nd2Ir2O7, or alloys, element substitutions, or mixtures thereof. Furthermore, the anomalous Nernst coefficient may be increased by adding an optional substance such as MgO to these compositions. Therefore, the thermoelectric conversion unit 31 is not limited to those composed solely of the above-mentioned compositions. The mechanism by which the anomalous Nernst effect is exhibited is arbitrary, but examples include those resulting from an antiferromagnetic magnetic structure with a non-collinear spin structure, or a unique band structure called a Weyl point or nodal web. In these structures, the symmetry of the band structure, etc., makes the quantity representing the geometric characteristics (e.g., Chern number) finite, which is thought to be one of the factors that causes the anomalous Nernst effect. For example, the wave function of the electrons constituting the system acquires a Berry phase corresponding to the characteristic quantity, and this Berry phase functions as a virtual magnetic field acting on the electrons, which is thought to cause the anomalous Nernst effect. The geometric characteristic quantity is calculated, for example, from the band structure obtained by band calculation obtained from the microstructure (including the crystalline structure and magnetic structure) of the material. In this case, the Nernst coefficient tends to be larger than other manifestation mechanisms, making it easier to perform more accurate measurements and miniaturize the device. Furthermore, the material constituting the thermoelectric conversion unit 31 may be realized as a polycrystalline or single crystalline body of these materials. Note that the crystallographic domain of the single crystalline body needs to be uniform enough to observe asymmetric physical properties due to the reduction in symmetry associated with the manifestation of magnetic order. The thickness of the thermoelectric conversion section 31 in the first direction D1, more specifically, the thickness of the structure that exhibits the anomalous Nernst effect contained in the thermoelectric conversion section 31, is arbitrary, but specifically may be, for example, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, or 900 nm, and may be within a range between any two of the values ​​exemplified here.The thermoelectric material that exhibits the anomalous Nernst effect or the like may be mounted as the thermoelectric conversion unit 31 by any method, and any method can be used, including physical vapor deposition methods such as sputtering and ion plating, plating, chemical vapor deposition, molecular beam epitaxy (MBE), and various printing methods such as inkjet printing using droplets of the compound dissolved therein.

[0037] By utilizing the anomalous Nernst effect, the thermoelectric conversion unit 31 of this embodiment can be formed thinner and have a smaller volume than a thermoelectric conversion unit utilizing the Seebeck effect, while maintaining its sensitivity to heat flow (i.e., the magnitude of the thermoelectromotive force E relative to the temperature gradient J per unit area). Hereinafter, for convenience of explanation, a thermoelectric conversion unit utilizing the Seebeck effect may be referred to as a Seebeck element. Furthermore, by reducing the volume of the thermoelectric conversion unit 31 of this embodiment compared to a Seebeck element, the overall heat capacity can be reduced. Therefore, compared to a Seebeck element, the thermoelectric conversion unit 31 of this embodiment can respond to temperature changes of a measurement target, such as the power storage device 2, in a relatively short time, achieving high time resolution and high sensitivity. In some cases, these characteristics, which previously tended to be traded off, can be achieved simultaneously. This configuration allows for the detection of dynamics of instantaneous heat changes, such as abnormal heat generation, which cannot be detected by conventional thermometers or heat flow sensors.

[0038] The thermoelectric conversion unit 31 includes a first region 311 and a second region 312, and the first region 311 of the thermoelectric conversion unit 31 is connected to the protruding portion 332. As a result, heat from the heat source Q of the power storage device 2 is conducted through the first heat conduction unit 33 in the order of the main surface portion 331 and the protruding portion 332, and then from the protruding portion 332 to the thermoelectric conversion unit 31 via the first region 311. Heat exchange between the thermoelectric conversion unit 31 and the power storage device 2 occurs through this heat conduction path. The second region 312 is located in the direction of the temperature gradient J (i.e., the first direction D1) from the first region 311. The second region 312 can also be said to be located opposite the first region 311 in the thickness direction of the thermoelectric conversion unit 31, and has a front-back relationship with the first region 311.

[0039] <Second Heat Conduction Unit 34> The second heat conduction unit 34 includes a contact unit 341 and a heat transport unit 342, and the contact unit 341 of the second heat conduction unit 34 is connected to the second region 312. The contact unit 341 is arranged to cover the second region 312 of the thermoelectric conversion unit 31 when the power storage device 2 is viewed from above in the first direction D1. This makes it possible to suppress variations in temperature of the second region 312 of the thermoelectric conversion unit 31 depending on the position. Like the thermoelectric conversion unit 31, the contact unit 341 of this embodiment is configured in the shape of a rectangular flat plate whose thickness direction extends along the first direction D1.

[0040] The heat transporting part 342 is connected to the outer edge of the contact part 341, extends from the outer edge in the second direction D2, and is connected to the heat bath 32 (not shown). The heat bath 32 exchanges heat with the second region 312 of the thermoelectric conversion part 31 via the heat transporting part 342 and the contact part 341 in this order. This makes it easier to maintain the surface temperature of the second region 312 of the thermoelectric conversion part 31 at the reference temperature Tb of the heat bath 32. Meanwhile, the surface temperature of the first region 311 of the thermoelectric conversion part 31 rises due to heat generated from the heat source Q within the housing 21. As a result, a temperature gradient J occurs in the thermoelectric conversion part 31 along the first direction D1 due to the difference between the surface temperatures of the first region 311 and the second region 312. As described above, the surface temperature of the second region 312 is easily maintained at the reference temperature Tb, so it is possible to grasp the temperature gradient J that occurs in the thermoelectric conversion unit 31 depending on the temperature of the second heat conduction unit 34, thereby increasing the amount of information that can be obtained from the thermoelectromotive force E. Therefore, it is possible to perform a wider variety of heat-related processes.

[0041] In this embodiment, the surface of the contact portion 341 that is in contact with the second region 312 and that is positioned opposite in the first direction D1 is exposed to air. Therefore, if the temperature of the thermoelectric conversion unit 31 becomes excessively high, the heat accumulated in the thermoelectric conversion unit 31 is released into the air through the contact portion 341. Therefore, the second heat conduction portion 34 (particularly the contact portion 341) functions as a heat dissipation portion that can dissipate at least a portion of the heat that flows into the thermoelectric conversion unit 31 through heat exchange. In other words, the second heat conduction portion 34 includes such a heat dissipation portion. With this configuration, heat generated by heat generation in the power storage device 2 can be released from the heat dissipation portion, thereby suppressing an excessive temperature rise in the thermoelectric conversion unit 31.

[0042] 3. Hardware Configuration of Information Processing Device 4 In this section, an example of the hardware configuration of the above-mentioned information processing device 4 will be described. Fig. 6 is a block diagram showing the hardware configuration of the information processing device 4. The information processing device 4 includes a communication bus 40, a communication unit 41, a storage unit 42, a processor 43 as a control unit, a display unit 44, and an input unit 45. These components are electrically connected via the communication bus 40 inside the information processing device 4.

[0043] <Communication Unit 41> The communication unit 41 is preferably a wired communication means such as USB, IEEE 1394, Thunderbolt (registered trademark), or wired LAN network communication, but may also include wireless LAN network communication, mobile communication such as 3G / LTE / 5G, or BLUETOOTH (registered trademark) communication as needed. In other words, it is more preferable to implement the communication unit 41 as a collection of multiple communication means. In other words, the information processing device 4 may communicate various information from the outside via the communication unit 41 and the network.

[0044] <Storage Unit 42> The storage unit 42 stores various pieces of information defined above. This can be implemented, for example, as a storage device such as a solid state drive (SSD) that stores various programs and the like related to the information processing device 4 executed by the processor 43, or as a memory such as a random access memory (RAM) that stores temporarily required information (arguments, arrays, etc.) related to the program calculations. The storage unit 42 stores various programs, variables, etc. related to the information processing device 4 executed by the processor 43.

[0045] <Processor 43> The processor 43 processes and controls the overall operations related to the information processing device 4. The processor 43 is, for example, a central processing unit (CPU) not shown. The processor 43 realizes various functions related to the information processing device 4 by reading out predetermined programs stored in the storage unit 42. In other words, information processing by software stored in the storage unit 42 is specifically realized by the processor 43, which is an example of hardware, and can be executed as each functional unit included in the processor 43. These will be described in more detail in the next section. Note that the processor 43 is not limited to being single, and multiple processors 43 may be provided for each function. A combination of these may also be used.

[0046] <Display Unit 44> The display unit 44 may be included in the housing of the information processing device 4 or may be externally attached. The display unit 44 displays a graphical user interface (GUI) screen that can be operated by the user. This is preferably implemented by selectively using display devices such as a CRT display, a liquid crystal display, an organic EL display, or a plasma display depending on the type of information processing device 4.

[0047] <Input Unit 45> The input unit 45 may be included in the housing of the information processing device 4 or may be externally attached. For example, the input unit 45 may be implemented as a touch panel integrated with the display unit 44. A touch panel allows the user to input tapping, swiping, and the like. Of course, a switch button, a mouse, a QWERTY keyboard, or the like may be used instead of a touch panel. That is, the input unit 45 accepts an operation input made by the user. The input is transferred as a command signal to the processor 43 via the communication bus 40, and the processor 43 can execute predetermined control or calculation as necessary.

[0048] 4. Functional Configuration of Information Processing Device 4 This section shows an example of the functional configuration of the above-described processor 43. Fig. 7 is a diagram showing an example of functional units included in the processor 43. The processor 43 includes an acquisition unit 431, a detection unit 432, a determination unit 433, a change unit 434, an estimation unit 435, a device control unit 436, and a display processing unit 437.

[0049] The acquisition unit 431 is configured to acquire information from the power storage device 2 or another device and execute an acquisition step. The acquisition unit 431 is configured to be able to acquire various pieces of information by reading out various pieces of information stored in a storage area that is at least a part of the memory unit 42 and writing the read out information to a working area that is at least a part of the memory unit 42. The storage area is, for example, an area of ​​the memory unit 42 that is implemented as a storage device such as an SSD. The working area is, for example, an area that is implemented as a memory such as a RAM.

[0050] The detection unit 432 is configured to detect an abnormality in a device such as the power storage device 2 based on the acquired various information and execute a detection step.

[0051] The determination unit 433 is configured to determine the operating state of the devices such as the power storage device 2 based on the acquired various information and execute a determination step.

[0052] The change unit 434 is configured to change the operation of the devices such as the power storage device 2 based on the acquired various information and execute a change step.

[0053] The estimation unit 435 is configured to estimate various information, such as the state of equipment such as the storage device 2 and the position of the heat source Q generated by the operation of the equipment, based on the various acquired information, and to execute the first estimation step and the second estimation step.

[0054] The device control unit 436 is configured to control the operation of the power storage device 2 and the driving device M1 as devices based on various information.

[0055] The display processing unit 437 is configured to display various types of information. The information can be presented to the user via the display unit 44 or another device. In such a case, for example, the display processing unit 437 controls the display unit 44 to display visual information such as screens, images including still images or moving images, icons, messages, etc. The display processing unit 437 may generate only rendering information for displaying the visual information on the information processing device 4 or a user terminal (not shown). Note that the display processing unit 437 may present the output information to the user without going through another device.

[0056] 5. Information Processing This section describes the information processing executed in the information processing system 1 described above. Note that the information processing may include any exception processing not shown. Exception processing includes the interruption of the information processing or the omission of each process. Selection or input performed in the information processing may be based on a user operation or may be performed automatically without relying on a user operation.

[0057] 5.1. First Information Processing This section describes the first information processing, which is an example of information processing executed by the above-described information processing system 1. Fig. 8 is an activity diagram showing an example of the flow of the first information processing executed in the information processing system 1. The information processing system 1 can detect abnormal operation of the power storage device 2 by performing the first information processing.

[0058] [Activity A1] First, in activity A1, the acquisition unit 431 acquires the thermoelectromotive force E. In this embodiment, the acquisition unit 431 acquires an output signal output from the comparison unit 351 based on the thermoelectromotive force E. In other words, the acquisition unit 431 indirectly acquires the thermoelectromotive force E. Thereafter, the determination unit 433 determines whether the acquired thermoelectromotive force E is equal to or less than the threshold voltage Vt1. In this embodiment, the comparison unit 351 outputs an output signal when the thermoelectromotive force E is greater than the threshold voltage Vt1. Therefore, the determination unit 433 may make this determination based on whether the acquisition unit 431 has acquired this output signal. In this embodiment, this determination is made for each of the multiple power storage devices 2, but is not limited thereto and may be made collectively for at least some of the power storage devices 2.

[0059] [Activity A2] If it is determined that the thermoelectromotive force E is equal to or less than the threshold voltage Vt1, the process proceeds to activity A2, where the determination unit 433 determines that the power storage device 2 is normal, and continues the operation of the power storage device 2. Thereafter, the process returns to activity A1, and the acquisition and determination of the thermoelectromotive force E are repeated.

[0060] [Activity A3] On the other hand, if it is determined that the thermoelectromotive force E is greater than the threshold voltage Vt1, the process proceeds to activity A3, and the detection unit 432 detects abnormal operation of the power storage device 2 accompanied by heat generation based on the thermoelectromotive force E. With this configuration, the change in temperature gradient J due to heat generation in the power storage device 2 changes in a shorter time period than the change in temperature due to heat generation in the power storage device 2, and therefore abnormal heat generation in the power storage device 2 can be detected with higher sensitivity than conventionally.

[0061] [Activity A4] Next, the process proceeds to activity A4, where the processor 43 turns off the switch 36 corresponding to the power storage device 2 for which abnormal operation has been detected. This restricts charging and discharging of at least the power storage device 2 that has been turned off. Detecting an abnormal operation also means determining the operating state of the power storage device 2. Therefore, the determination unit determines the operating state of the power storage device 2 based on the thermoelectromotive force E. With this configuration, the change in temperature gradient J due to heat generation by the power storage device 2 changes in a shorter time period than the change in temperature due to heat generation by the power storage device 2, and therefore the operating state of the power storage device 2 can be distinguished with higher sensitivity than before.

[0062] [Activity A5] Next, the processing proceeds to activity A5, where the display processing unit 437 notifies the user of the abnormal operation detection result. The display processing unit 437 visually notifies the user of information about the power storage device 2 in which the abnormal operation has been detected, for example, via the display unit 44. The information about the power storage device 2 includes, for example, the details of the abnormal operation of the power storage device 2. The notification method is not limited to this and may be any method, such as using sound or light. Thereafter, the first information processing ends.

[0063] To summarize the above, the information processing system 1 includes a thermoelectric conversion unit 31, a signal processing circuit 35 serving as a signal processing unit, and an information processing device 4. The thermoelectric conversion unit 31 is configured to generate a temperature gradient J through heat exchange with the power storage device 2 serving as a device, and is configured to generate a thermoelectromotive force E based on the temperature gradient J. The processor 43 of the information processing device 4 included in the signal processing unit includes an acquisition unit 431 and a detection unit 432. The acquisition unit 431 is configured to acquire the thermoelectromotive force E. The detection unit 432 is configured to detect abnormal operation of the power storage device 2 accompanied by heat generation based on the thermoelectromotive force E.

[0064] With this configuration, the change in temperature gradient J due to heat generation by the equipment changes in a shorter time than the change in temperature due to heat generation by the equipment, so abnormal heat generation by the equipment can be detected with higher sensitivity than conventional methods.

[0065] 5.2. Second Information Processing This section describes the second information processing, which is an example of the information processing executed by the above-described information processing system 1. FIG. 9 is an activity diagram showing an example of the flow of the second information processing executed in the information processing system 1. By performing the second information processing, the information processing system 1 can control the operation of the power storage device 2 and the like based on the acquired thermoelectromotive force E. Note that controlling the power storage device 2 is not limited to controlling the power storage device 2 by directly transmitting a signal to the power storage device 2, but also includes indirectly controlling the power storage device 2 by transmitting a signal to a device different from the power storage device 2 (for example, a power converter or a driving device M1) and controlling the operation of that device.

[0066] [Activity A11] First, in activity A11, the acquisition unit 431 acquires the required power P and the thermoelectromotive force E of the movable device M1. The acquisition of the thermoelectromotive force E may be performed in any manner, and if the signal processing circuit 35 includes a voltage measurement unit capable of measuring the thermoelectromotive force E, the acquisition unit 431 may acquire the value of the thermoelectromotive force E from the voltage measurement unit. Furthermore, if the signal processing circuit 35 includes multiple comparison units 351 in a manner that allows the thermoelectromotive force E to be compared with multiple threshold voltages, the acquisition unit 431 may acquire the results of comparison between the thermoelectromotive force E and each of the multiple threshold voltages.

[0067] [Activity A12] Next, the process proceeds to activity A12, where the processor 43 searches for the maximum output power Pmax corresponding to the thermoelectromotive force E based on predetermined reference information IF0. The reference information IF0 is information that defines the correspondence between the thermoelectromotive force E and the maximum output power Pmax, and is stored in the memory unit 42, etc. Because the thermoelectromotive force E is information that represents the heat flow associated with the temperature gradient J, the thermoelectromotive force E is information that indicates the temperature of the power storage device 2, specifically, the change in temperature over time. Therefore, the reference information IF0 is information that indicates the temperature of the power storage device 2 and the maximum output power Pmax that the power storage device 2 can output at that temperature. The reference information IF0 can be generated based on, for example, the results of a test performed in advance or the results of a predetermined simulation, and its format can be any format, such as a function, a lookup table, or a trained model.

[0068] The determination unit 433 then compares the acquired required power P with the maximum output power Pmax obtained by the search and determines whether they are larger or smaller. In this embodiment, the comparison unit 351 outputs the comparison result of the thermoelectromotive force E as a first electrical signal, and the change unit 434 changes the operation of the power storage device 2 based on the comparison result of the thermoelectromotive force E. With this configuration, the thermoelectromotive force E generated by the thermoelectric conversion unit 31 can be recognized as a difference from a reference value. Therefore, it becomes easier to stably change the operation of the power storage device 2 using the electrical signal output from the thermoelectric conversion unit 31. The change unit 434 changes whether to perform the next process, activity A13 or activity A14, based on the comparison result of the thermoelectromotive force E, for example.

[0069] [Activity A13] If the required power P is equal to or less than the maximum output power Pmax, the process proceeds to activity A13, where the device control unit 436 controls the power storage device 2 to output power in accordance with the required power P of the driving device M1. The output power of the power storage device 2 is controlled, for example, through the control of a power converter (not shown). Then, the process returns to activity A11.

[0070] [Activity A14] On the other hand, if the required power P is greater than the maximum output power Pmax, the process proceeds to activity A14, where the device control unit 436 limits the driving device M1 so that the required power P of the driving device M1 is equal to or less than the maximum output power Pmax, and causes the power storage device 2 to output power in accordance with the limited required power P. This allows the power storage device 2 to output power appropriate for its temperature state, thereby suppressing the progression of deterioration of the power storage device 2. In this way, the information processing system 1 searches for the maximum output power Pmax based on the thermoelectromotive force E, and controls the output power of the power storage device 2 so that it does not exceed the maximum output power Pmax.

[0071] To summarize the above, the information processing system 1 includes a thermoelectric conversion unit 31, a signal processing circuit 35 serving as a signal processing unit, and an information processing device 4. The thermoelectric conversion unit 31 is configured to generate a thermoelectromotive force E in response to a temperature gradient J generated in the thermoelectric conversion unit 31 by heat exchange with the power storage device 2 serving as a device. The processor 43 of the information processing device 4 included in the signal processing unit includes an acquisition unit 431 and a device control unit 436. The acquisition unit 431 is configured to acquire the thermoelectromotive force E. The device control unit 436 is configured to control the operation of the device based on the acquired thermoelectromotive force E.

[0072] With this configuration, the change in temperature gradient due to heat generation from the device occurs in a shorter time than the change in temperature due to heat generation from the device, so the device can be controlled with a faster response speed than before.

[0073] 5.2. Third Information Processing This section describes third information processing, which is an example of information processing executed by the above-described information processing system 1. Fig. 10 is an activity diagram showing an example of the flow of the third information processing executed in the information processing system 1. By performing the third information processing, the information processing system 1 can further estimate the state of charge or state of health of the power storage device 2.

[0074] [Activity A21] First, in activity A21, the acquisition unit 431 acquires the required power P and thermoelectromotive force E of the moving machine M1. The details of the process are the same as those of activity A11.

[0075] [Activity A22] Next, the process proceeds to activity A22, where the processor 43 searches for the maximum output power Pmax corresponding to the thermoelectromotive force E based on predetermined reference information IF0. The details of the process are the same as those of activity A12. Thereafter, the determination unit 433 compares the acquired required power P with the maximum output power Pmax obtained by the search, and determines which is larger or smaller.

[0076] [Activity A23] If the required power P is equal to or less than the maximum output power Pmax, the process proceeds to activity A23, where the device control unit 436 controls the power storage device 2 to output power in accordance with the required power P of the driving device M1. The details of the process are the same as those of activity A13. Then, the process proceeds to activity A25.

[0077] [Activity A24] On the other hand, if the required power P is greater than the maximum output power Pmax, the process proceeds to activity A24, where the device control unit 436 limits the driving device M1 so that the required power P of the driving device M1 is equal to or less than the maximum output power Pmax, and causes the power storage device 2 to output power according to the limited required power P. The details of the process are the same as those of activity A14. Thereafter, the process proceeds to activity A25.

[0078] [Activity A25] In activity A25, the acquisition unit 431 acquires the output power of the power storage device 2 and stores the history of the output power in the storage unit 42 or the like. The output power of the power storage device 2 is an example of information about the second electrical signal output from the power storage device 2, and may be an output voltage, an output current, or the like. Then, the process returns to activity A21.

[0079] [Activity A26] After activity A25, in activity A26, the estimation unit 435 estimates the state of charge (SOC) or state of health (SOH) of the power storage device 2 based on the output history of the output power of the power storage device 2 and the thermoelectromotive force E, and updates the existing SOC and SOH to the estimated values. This configuration can further stabilize the operation of the power storage device 2. Any method can be used to estimate the state of the power storage device 2. For example, the estimation unit 435 estimates the temperature and temperature change of the power storage device 2 based on the thermoelectromotive force E. Next, the estimation unit 435 compares the estimated temperature change with the output history of the output power to estimate the power consumption inside the power storage device 2 due to, for example, discharging of the power storage device 2 at that temperature. Next, the estimation unit 435 estimates the internal resistance of the power storage device 2 based on the power consumption inside the power storage device 2 and the output voltage of the power storage device 2. The internal resistance is one of the indicators representing the SOH of the power storage device 2. By correcting such internal resistance with temperature, the estimation unit 435 can estimate the SOH that reflects the temperature of the power storage device 2. Similarly, the estimation unit 435 can estimate the current SOC of the power storage device 2 while taking into consideration the temperature state of the power storage device 2 by performing calculations such as integrating the power output to the driving machine M1 and the power consumed inside the power storage device 2 and subtracting the integrated value from the power capacity in the fully charged state.

[0080] [Activity A27, Activity A28] Furthermore, when the third information processing is being performed, the detection unit 432 may detect in activity A27 that the thermoelectromotive force E has exceeded the threshold voltage Vt1. In this case, the processing exceptionally proceeds to activity A28, and the detection unit 432 detects an abnormal operation of the power storage device 2 that is accompanied by heat generation, based on the thermoelectromotive force E.

[0081] [Activity A29] The process then proceeds to activity A29, where the processor 43 turns off the switch 36 corresponding to the power storage device 2 in which the abnormal operation has been detected. Details of the process are the same as those of activity A4.

[0082] [Activity A30] The process then proceeds to activity A30, where the display processing unit 437 notifies the user of the abnormal operation detection result. The details of the process are the same as those of activity A5. Then, the third information processing ends.

[0083] The information processing may be performed singly or in combination. The information processing may be performed independently, in parallel, or in cooperation with each other.

[0084] 5. Configuration Example of Information Processing System 1 for Estimating Position Information, etc. of Heat Generation Positions in Power Storage Device 2 This section describes a configuration example of an information processing system 1 for estimating position information, etc. of heat generation positions in power storage device 2. For convenience of explanation, power storage unit BU is configured so that thermoelectric conversion unit 31 is in contact with first region 311 without first heat conduction unit 33 therebetween. However, as described above, the same applies when thermoelectric conversion unit 31 is in contact with housing 21 via first heat conduction unit 33. Figure 11 is a cross-sectional view of power storage device 2 and thermoelectric conversion unit 31 in contact with power storage device 2, taken along a plane perpendicular to third direction D3.

[0085] 11 , the heat source Q may be located at a position away from the surface of the housing 21 in the first direction D1. Therefore, the temperature of the heat source Q deviates from the surface temperature of the housing 21 (in other words, the temperature of the first region 311) by a temperature difference ΔT. Therefore, the surface temperature of the housing 21 estimated from the temperature gradient J deviates by the temperature difference ΔT.

[0086] In contrast, the estimation unit 435 of this embodiment uses the temperature of the first region 311 as the detected temperature Td and constructs a thermal circuit model M of the heat conduction path from the first region 311 to the heat source Q by simulation or the like. FIG. 12 is a diagram showing an example of the thermal circuit model M. The estimation unit 435 may use the thermal circuit model M to estimate various information, such as the deep temperature of the heat source Q and its position information (e.g., the distance in the first direction D1 from the surface of the housing 21 to the heat source Q) from the thermoelectromotive force E. The thermal circuit model M is expressed, for example, as a parallel connection of a thermal resistance R1 and a thermal capacitance C1, and the estimation unit 435 estimates these parameters by simulation or the like. The relationship between the temperature difference ΔT, the thermal resistance, and the thermal capacitance C1 is expressed, for example, by the following relational expression: Q represents the heat generation amount of the heat source Q, and n is a natural number representing the number of steps representing the time change in the heat generation amount of the heat source Q.

[0087] Here, α=t_sampling / (R1×C1) and k=t_sampling / C1, where t_sampling indicates the time of the sampling period.

[0088] In summary, the estimation unit 435 is configured to estimate position information of the heat generation position of the power storage device 2 relative to the surface of the power storage device 2, based on a predetermined thermal conduction model of the power storage device 2 and the temperature of the surface of the power storage device 2 based on the thermoelectromotive force E. With this configuration, it becomes easier to grasp the position of a heat source present inside the power storage device 2.

[0089] When correcting temperature changes, the information processing system 1 may further include a temperature adjustment element 6. FIG. 13 is a cross-sectional view of the power storage device 2, etc., taken along a plane perpendicular to the third direction D3, when the thermoelectric conversion unit 31 is in contact with the power storage device 2 via the temperature adjustment element 6. The temperature adjustment element 6 is configured to adjust the temperature of the first region 311 of the thermoelectric conversion unit 31 based on control by the information processing device 4, etc., and is implemented using, for example, a seat heater or a Peltier element. The temperature adjustment element 6 is disposed between the housing 21 and the first region 311 of the thermoelectric conversion unit 31. Preferably, the temperature adjustment element 6 includes a conduction path for heat flow from the housing 21 to the first region 311. The information processing device 4 controls the temperature adjustment element 6 based on the thermoelectromotive force E associated with the temperature gradient J, and drives the temperature adjustment element 6 so as to reduce the thermoelectromotive force E. As a result, the temperature adjustment element 6 adjusts the temperature of the first region 311 so that the temperature gradient J between the first region 311 and the second region 312 is less than a predetermined value. In this way, a compact control system can be constructed by performing closed-loop control using the thermoelectric conversion unit 31, the information processing device 4, and the temperature adjustment element 6. Furthermore, the estimation unit 435 may estimate various information such as internal parameters of the thermal circuit model M (e.g., thermal resistance R1, heat capacity C1, etc.), position information of the heat source Q, and the degree of deterioration of the power storage device 2 from the control values, heat flow (temperature gradient J), temperature response, etc. of the temperature adjustment element 6 at this time.

[0090] 6. Alternative Examples of the Signal Processing Circuit 35 This section describes an alternative example of the signal processing circuit 35 described above. FIG. 14 is a diagram showing an alternative example of the signal processing circuit 35. As shown in FIG. 14, the signal processing circuit 35 may further include a capacitor 353. The capacitor 353 is disposed between the thermoelectric conversion unit 31 and the non-inverting input terminal of the comparison unit 351, and converts the first electrical signal input to the comparison unit 351 from the thermoelectromotive force E into a signal corresponding to the time derivative of the thermoelectromotive force E, i.e., the rate of change of the temperature gradient J per unit time. In this case, the information processing device 4 can perform the above-described control based on the signal corresponding to the time derivative of the thermoelectromotive force E. This signal is particularly suitable for detecting a tendency for sudden heat generation due to, for example, leakage of the electrolyte in the power storage unit 22.

[0091] Furthermore, the function of the signal processing circuit 35 may be realized by the information processing device 4. That is, the information processing device 4 may function as a signal processing unit. In other words, the above-described signal processing circuit 35 is not limited to being implemented by an analog circuit, but may be realized by the processor 43 of the information processing device 4 executing a predetermined program. Note that the specific configuration of the signal processing circuit 35 is arbitrary and is not limited to that described above.

[0092] [Others] The above-described aspect of the information processing system 1 is merely an example, and the present invention is not limited to this.

[0093] In the activity A2 of each of the information processing operations described above, the detection unit 432 detects abnormal operation of the power storage device 2, which involves heat generation, based on the comparison result between the thermoelectromotive force E and the threshold voltage Vt1. However, the manner of detecting abnormal operation is not limited to this and may be arbitrary. For example, the detection unit 432 may detect abnormal operation of the power storage device 2 based on whether the acquired information about the thermoelectromotive force E satisfies a pre-specified condition indicating abnormal operation. The condition may be specified based on test results, simulation results, etc. The method of specifying the condition is arbitrary, and the condition may be specified by processing the test results, etc. using an arbitrary statistical method, or by using a trained model that is trained by inputting the test results, etc. The learning algorithm of the trained model may be arbitrary, and examples include supervised learning, semi-supervised learning, unsupervised learning, and reinforcement learning. The information about the thermoelectromotive force E is not limited to the thermoelectromotive force E itself, but may include various aspects such as a differential value, an integral value, and time-series information of the thermoelectromotive force E. In particular, the detection unit 432 may detect abnormal operation of the power storage device 2 based on time-series information about the thermoelectromotive force E. This allows detection of abnormal operation to be performed taking into consideration the influence of continuous usage of equipment such as the power storage device 2, thereby improving convenience.

[0094] As in the case of activity A2, the change unit 434 may change the operation of the power storage device 2 in activity A12 or the like based on something other than the result of comparing the thermoelectromotive force E with various reference values ​​such as the maximum output power Pmax. The change unit 434 may change the operation of the power storage device 2 based on whether the thermoelectromotive force E is within a range of thermoelectromotive forces E corresponding to the changed operation. In particular, the change unit 434 may change the operation of the power storage device 2 based on time-series information about the thermoelectromotive force E. This makes it possible to change the operation of a device such as the power storage device 2 in consideration of the influence of continuous usage of the device such as the power storage device 2, thereby reducing the burden on the device, for example.

[0095] The temperature adjustment unit is not limited to the heat bath 32, but may be a heat sink, a water cooling device, or the like, and may be any unit as long as it can adjust the temperature of the second heat conduction unit 34 or the second region 312 of the thermoelectric conversion unit 31. With a configuration including such a temperature adjustment unit, the change in temperature gradient J due to heat generation in the power storage device 2 changes in a shorter time period than the change in temperature due to heat generation in the power storage device 2, and therefore abnormal heat generation in the power storage device 2 can be detected with higher sensitivity than conventionally.

[0096] The first signal is not limited to the thermoelectromotive force E, but may be an electric signal such as a current or power caused by the thermoelectromotive force E, or a magnetic force induced by the current.

[0097] The second signal is not limited to voltage, current, and power, and may be any signal that includes information that allows the SOC or SOH of the power storage unit 22 of each power storage device 2 to be estimated.

[0098] The main surface portion 331 does not have to be arranged along the outer edge of the housing 21, and the shape of the main surface portion 331 is arbitrary as long as it can transfer heat from the heat source Q to the thermoelectric conversion unit 31. For example, the main surface portion 331 may be formed such that, when the housing 21 is viewed in plan from the first direction D1, the outer edge of the main surface portion 331 encompasses an area where the power storage unit 22 may be present.

[0099] The signal processing system 3 does not necessarily have to include the first heat conduction unit 33. FIG. 15 is a diagram showing an example of a signal processing system 3 that does not include the first heat conduction unit 33. As shown in FIG. 15, the thermoelectric conversion unit 31 is disposed so that the first region 311 is in direct contact with the housing 21 without the first heat conduction unit 33 therebetween. In this case, the shape of the thermoelectric conversion unit 31 is similar to the main surface 331 of the first heat conduction unit 33 described above, and the thermoelectric conversion unit 31 is formed so that the outer edge of the housing 21 encompasses the outer edge of the thermoelectric conversion unit 31 when viewed in plan from the first direction D1. This allows the generation of the heat source Q to be detected over a wider range.

[0100] The first heat conducting portion 33 may not have the main surface portion 331 but may have the protruding portion 332. In this case, the protruding portion 332 is disposed so as to contact at least a part of the outer edge of the housing 21.

[0101] The signal processing system 3 may not include the second heat conducting unit 34. For example, the thermoelectric conversion unit 31 may be configured so that the second region 312 is in direct contact with the heat bath 32 without the second heat conducting unit 34. For example, the heat bath 32 may be arranged so as to cover the second region 312 of the thermoelectric conversion unit 31 from the first direction D1. Furthermore, the signal processing system 3 may not include the heat bath 32.

[0102] The thermoelectric conversion unit 31 may be attached at any position as long as it is possible to detect the presence of the heat source Q, and is not limited to the surface of the housing 21. Fig. 16 is a diagram showing an example of an attachment mode of the thermoelectric conversion unit 31. As shown in Fig. 16, the thermoelectric conversion unit 31 may be housed inside the housing 21. In this case, the shape of the thermoelectric conversion unit 31 is arbitrary, and may be, for example, a flat plate shape as shown in Fig. 15.

[0103] The thermoelectric conversion unit 31 is not limited to one that exhibits the anomalous Nernst effect as described above, and may be configured to exhibit the Seebeck effect, etc. In this case, the thermoelectric conversion unit 31 needs to be wired so as to extract the thermoelectromotive force E in a direction parallel to the temperature gradient J, because the temperature gradient J induces a thermoelectromotive force E that includes a component parallel to the temperature gradient J.

[0104] The object connected to the power storage unit BU is not limited to an object driven by power from the power storage unit BU, such as the above-described movable device M1. For example, the power storage unit BU may be connected to a charging device that supplies power to the power storage unit BU. The charging device includes, for example, a power source such as a commercial power source and a power converter that converts power from the power source. In this case, the information processing device 4 of the power storage unit BU transmits required power P to the charging device, and the power storage unit BU transmits power corresponding to the required power P to the power storage unit BU. The information processing described above can also be applied to the information processing system 1 configured in this manner.

[0105] In the above embodiment, the case where the power storage device 2 generates heat from the heat source Q has been described, but the same applies to the case where the power storage device 2 absorbs heat from the heat source Q. That is, the same applies to the case where the temperature of the first region 311 of the thermoelectric conversion unit 31 is lower than the temperature of the second region 312 due to circumstances such as the temperature of the housing 21 being lower than the temperature of the heat bath 32, etc. Therefore, the heat exchange between the power storage device 2 and the thermoelectric conversion unit 31 is not limited to the case where heat is transferred from the power storage device 2 to the thermoelectric conversion unit 31, but may also include the case where heat is transferred from the thermoelectric conversion unit 31 to the power storage device 2.

[0106] The information processing performed by the information processing system 1 may be on-premise or cloud-based. As a cloud-based external device, for example, the above-described functions and processes may be provided in the form of SaaS (Software as a Service) or cloud computing.

[0107] In the above embodiment, the signal processing system 3 and the information processing device 4 performed various storage and control operations, but multiple external devices may be used instead of the signal processing system 3 and the information processing device 4. That is, various information and programs may be stored in a distributed manner in multiple external devices using blockchain technology or the like.

[0108] The above embodiment is not limited to the information processing system 1, and may be an information processing method or an information processing program.

[0109] Therefore, to summarize the above, the information processing method executed by the information processing system 1 includes the following steps. The thermoelectric conversion step generates a thermoelectromotive force E in accordance with a temperature gradient J generated in the thermoelectric conversion unit 31 by heat exchange with the power storage device 2 as a device. The power storage device 2 as a device is configured to generate heat in accordance with the operating state of the device. The determination unit 433 determines the operating state of the device in accordance with the thermoelectromotive force E.

[0110] To summarize the above, the information processing method executed by the information processing system 1 includes the following steps: In the thermoelectric conversion step, a temperature gradient J is generated by heat exchange with the power storage device 2, and a thermoelectromotive force E is generated based on the temperature gradient J. In the acquisition step, the thermoelectromotive force E is acquired. In the detection step, an abnormal operation of the power storage device 2 that generates heat is detected based on the thermoelectromotive force E.

[0111] With this configuration, the change in temperature gradient J due to heat generation from the storage device 2 changes in a shorter time than the change in temperature due to heat generation from the storage device 2, so abnormal heat generation from the storage device 2 can be detected with higher sensitivity than before.

[0112] It may be provided in the following manner.

[0113] (1) An information processing system comprising a thermoelectric conversion unit and a signal processing unit, wherein the thermoelectric conversion unit is configured to generate a temperature gradient through heat exchange with an equipment and to generate a thermoelectromotive force based on the temperature gradient, and the signal processing unit comprises an acquisition unit and a detection unit, wherein the acquisition unit is configured to acquire the thermoelectromotive force, and the detection unit is configured to detect abnormal operation of the equipment involving heat generation based on the thermoelectromotive force.

[0114] With this configuration, the change in temperature gradient due to heat generation by the equipment changes in a shorter time than the change in temperature due to heat generation by the equipment, so abnormal heat generation by the equipment can be detected with higher sensitivity than conventional methods.

[0115] (2) An information processing system comprising a thermoelectric conversion unit and a signal processing unit, wherein the thermoelectric conversion unit is configured to generate a thermoelectromotive force in response to a temperature gradient generated in the thermoelectric conversion unit by heat exchange with an equipment, the signal processing unit comprising an acquisition unit and an equipment control unit, wherein the acquisition unit is configured to acquire the thermoelectromotive force, and the equipment control unit is configured to control the operation of the equipment based on the acquired thermoelectromotive force.

[0116] With this configuration, the change in temperature gradient due to heat generation from the device occurs in a shorter time than the change in temperature due to heat generation from the device, so the device can be controlled with a faster response speed than before.

[0117] (3) In the information processing system described in (1) or (2) above, the thermoelectric conversion unit is configured to generate the thermoelectromotive force including a component generated in a direction different from the temperature gradient.

[0118] With this configuration, it becomes easier to measure thermoelectric power from a direction different from the temperature gradient, which reduces the amount of wiring between the device and the thermoelectric conversion unit, thereby suppressing a decrease in sensitivity to temperature gradients.

[0119] (4) The information processing system according to any one of (1) to (3) above, further comprising a first heat conduction unit, the first heat conduction unit connecting the device and the thermoelectric conversion unit.

[0120] According to this configuration, heat exchange between the device and the thermoelectric conversion section occurs via the first heat conduction section, which makes it easier to reduce variations in thermoelectromotive force due to different heat generation positions in the device.

[0121] (5) In the information processing system described in (4) above, the first heat conduction unit has a protrusion, and the protrusion is configured to protrude from the device when the device is viewed in a planar view from a predetermined first direction, and the thermoelectric conversion unit is connected to the protrusion.

[0122] According to such a configuration, the thermoelectromotive force of the thermoelectric conversion unit can be measured more easily, and therefore the degree of freedom in arranging devices and the like can be improved.

[0123] (6) An information processing system according to any one of (1) to (5) above, further comprising a second heat conduction unit, wherein the thermoelectric conversion unit includes a first region in which heat exchange with the equipment takes place and a second region located from the first region in the direction of the temperature gradient, and the second heat conduction unit is connected to the second region.

[0124] With this configuration, it is possible to grasp the temperature gradient occurring in the thermoelectric conversion unit according to the temperature of the second heat conducting unit, thereby increasing the amount of information obtained from the thermoelectromotive force, and therefore enabling a wider variety of heat-related processing to be performed.

[0125] (7) In the information processing system described in (6) above, the second heat conducting portion is connected to a temperature adjusting portion that can adjust the temperature of the second heat conducting portion.

[0126] With this configuration, it becomes easier to grasp the temperature gradient of the thermoelectric conversion section more accurately.

[0127] (8) In the information processing system described in (6) or (7) above, the second heat conduction section is provided with a heat dissipation section capable of dissipating at least a portion of the heat flowing into the thermoelectric conversion section by the heat exchange.

[0128] According to this configuration, heat generated by the device can be released from the heat dissipation section, thereby suppressing an excessive temperature rise in the thermoelectric conversion section.

[0129] (9) In the information processing system described in any one of (6) to (8) above, the second thermal conduction section is configured to be connected to a heat bath of a predetermined reference temperature, thereby maintaining the temperature of the second region at approximately the reference temperature.

[0130] According to this configuration, the operating temperature of the thermoelectric conversion unit is stabilized, and therefore the accuracy of detecting the heat generation state of the device can be improved.

[0131] (10) In the information processing system described in (9) above, the signal processing unit further includes a comparison unit and a change unit, the comparison unit is configured to compare a first signal resulting from the thermoelectromotive force of the thermoelectric conversion unit with a predetermined reference value, and the change unit is configured to change the operation of the equipment based on the comparison result of the first signal.

[0132] With this configuration, the thermoelectric power generated by the thermoelectric converter can be detected as a difference from a reference value, making it easier to stably change the operation of the device using the signal output from the thermoelectric converter.

[0133] (11) In the information processing system described in any one of (1) to (10) above, the device is a power storage device capable of charging and discharging power, the signal processing unit further includes a first estimation unit, the acquisition unit is configured to be able to acquire information regarding a second signal output from the power storage device, and the first estimation unit is configured to estimate the charge state or health state of the power storage device based on the output history of the second signal and the thermoelectromotive force.

[0134] With this configuration, the operation of the power storage device can be made more stable.

[0135] (12) In the information processing system described in any one of (1) to (11) above, the thermoelectric conversion unit is configured so that the thermoelectromotive force changes in accordance with a change in temperature of the surface of the device due to heat generation, and the signal processing unit further includes a second estimation unit, and the second estimation unit is configured to estimate position information of the heat generation position of the device relative to the surface of the device based on a predetermined thermal conduction model of the device and the temperature of the surface of the device based on the thermoelectromotive force.

[0136] This configuration makes it easier to determine the location of a heat source inside the device.

[0137] (13) The information processing system according to any one of (1) to (12) above, further including the device.

[0138] With this configuration, the change in temperature gradient due to heat generation by the equipment changes in a shorter time than the change in temperature due to heat generation by the equipment, so abnormal heat generation by the equipment can be detected with higher sensitivity than conventional methods.

[0139] (14) An information processing method, comprising the following steps: in the thermoelectric conversion step, a thermoelectric power is generated in accordance with a temperature gradient generated in a thermoelectric conversion unit by heat exchange with an equipment, wherein the equipment is configured to generate heat in accordance with the operating state of the equipment; and in the determination step, the operating state of the equipment is determined in accordance with the thermoelectric power.

[0140] With this configuration, the change in temperature gradient due to heat generation from the device occurs in a shorter time than the change in temperature due to heat generation from the device, so the operating state of the device can be determined with higher sensitivity than before.

[0141] (15) An information processing method comprising the following steps: in the thermoelectric conversion step, a temperature gradient is generated by heat exchange with an equipment, and a thermoelectromotive force is generated based on the temperature gradient; in the acquisition step, the thermoelectromotive force is acquired; and in the detection step, abnormal operation of the equipment accompanied by heat generation is detected based on the thermoelectromotive force.

[0142] With this configuration, the change in temperature gradient due to heat generation from the device changes in a shorter time than the change in temperature due to heat generation from the device, so abnormal heat generation in the device can be detected with higher sensitivity than in the past.

[0143] Finally, while various embodiments of the present disclosure have been described, they are presented as examples and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as defined in the claims.

[0144] Furthermore, please note the following points:

[0145] Up until now, efforts have been made to ensure system safety by measuring the temperature at a single point. Currently, a temperature sensor is used to detect abnormal heat generation in the battery. This means that it can only detect when the temperature rises and an abnormal condition occurs. Also, since it can only detect localized temperature increases, it may not be detected until the temperature becomes quite high. Currently, because abnormal heat generation is measured by temperature, an abnormality cannot be detected until the battery warms up. Only localized temperatures can be detected.

[0146] By using a thin-film heat flow sensor that can measure the amount of heat generated, it is possible to stop the discharge or charging of the battery before an abnormal condition progresses. In addition, because it is possible to measure a range using a surface or an electric heat path, it is possible to create a configuration that makes it difficult to overlook abnormal areas. Because the amount of heat generated can be measured directly, it is possible to make measurements more quickly and to comprehensively detect abnormal heat generation.

[0147] This embodiment will be described. In this embodiment, a heat flow sensor that monitors the amount of heat generated is attached to the battery pack, enabling more rapid anomaly detection than temperature detection. Furthermore, by attaching the sensor to a larger area, anomaly detection can be performed over a larger range.

[0148] From the viewpoint of responsiveness, the heat flow sensor according to this embodiment is preferably a thin-film type heat flow sensor based on the anomalous Nernst effect. The element of the heat flow sensor (i.e., thermoelectric conversion device) may be composed of a compound exhibiting the anomalous Nernst effect. The element may be composed of, for example, a topological ferromagnet or a topological antiferromagnet called a Weyl semimetal, or may be composed of a ferrimagnet, or a combination thereof. The topological ferromagnet may be Co ２ Co such as MnGa ２ The metal may have a TX composition (where X is any one of Si, Ge, Sn, Al, and Ga), or the composition formula may be Fe ３ The topological antiferromagnet may be an alloy of a known topological ferromagnet, such as a metal represented by X (X is a stoichiometric composition of a typical element or transition element such as Al or Ga). ３The element may be a known topological antiferromagnetic material such as X (X is one or more elements selected from Sn, Ge, Ga, Pt, Ir, and Rh, or a compound thereof). The compound constituting the element may be, for example, an alloy containing a transition metal, and the alloy may be a compound having a crystal structure with Kagome lattice planes of the transition metal, and may exhibit the anomalous Nernst effect. The ferrimagnetic material is also not particularly limited as long as it exhibits the anomalous Nernst effect. The structure of the element is not particularly limited, and known materials can be used.

[0149] The heat flow sensor may also be directly mounted on the battery pack. Because it is a thin-film heat flow sensor, a PCB or other substrate for the sensor is not required. The heat flow sensor may be mounted on each cell, or in the case of a multi-cell system, it may be mounted on each cell.

[0150] A heat sink may also be provided on the heat flow sensor. The heat sink may be a known type, but the structure must be designed appropriately. Since the heat flow of the heat flow sensor can be adjusted using a heat sink, a thermal design with a heat sink may be used. The heat sink only needs to ensure a heat flow path, and it goes without saying that the optimal shape for each design may be used. Furthermore, it is not limited to using a heat sink; it is even better to use cooling means such as air cooling or water cooling to manage the thermal state, and it goes without saying that performance can be further improved by using a temperature sensor to manage the temperature of the heat flow sensor in this case. It also goes without saying that this cell may be a multi-cell.

[0151] The heat flow sensor may also be installed inside the battery cell. Because it is a thin-film heat flow sensor, it can detect heat generation even if it is installed inside the battery cell as long as the terminals are exposed. In this case, there is no problem with the installation location as long as it is chemically stable, such as between the case and the inside of the battery, or between the electrodes. In this case, there is no problem with using the electrodes or case as a heat sink. The cell may also be a multi-cell.

[0152] A heat conduction path may also be provided. A heat conduction path is created to the heat flow sensor, and the heat is conducted and the heat flow is detected. This makes it possible to detect heat even in places where it is difficult to insert a sensor. It is also preferable to use fine ceramics, semiconductors, resins, paste materials, etc. that are electrically insulated from the heat conduction path and the heat flow sensor but allow heat to pass through. Furthermore, even if the heat flow sensor makes electrical contact with the heat conduction path, noise will increase, but measurements will still be possible. The heat conduction path may be made of existing materials such as Al electrodes, which are used in batteries.

[0153] An example of a battery fail-safe system based on the heat flow detection system of this embodiment is shown below. Battery charging and discharging can be stopped using the absolute value or slope of the heat generation amount Q, a value derived from the heat generation amount, or a calculated value using the heat generation amount and other parameters as a judgment value. By incorporating such a fail-safe function, more reliable battery management can be achieved. The following equations are written using analog circuits, but digital control is also acceptable. Furthermore, the above information can be used to provide feedback to the battery charging and discharging control, enabling more reliable battery management.

[0154] Furthermore, for multiple batteries, if a battery is detected to be generating a lot of heat during charging or discharging, charging or discharging is temporarily stopped and switching is performed at a duty ratio that reduces the heat flow, thereby extracting the necessary power from the multiple batteries. Other methods may also be used as long as balancing is possible.

[0155] Furthermore, while the SOH (State of Health) of a battery has traditionally been estimated using information on the battery's internal impedance, current, voltage, number of charge / discharge cycles, and temperature history, incorporating heat generation data into this information can further improve the accuracy of the SOH. For example, it is possible to detect battery degradation by monitoring the heat generation rate under the same voltage and current drive conditions. Furthermore, comparisons using unit energy or similar parameters enable real-time DeSOH comparisons. Needless to say, this data can also be used to estimate other battery characteristic parameters. Furthermore, this data can be used to calculate the battery's lifespan and recommend replacement.

[0156] In another embodiment, the deep temperature of the battery can be measured from the amount of heat generated by the battery. This measurement information can be used in the system. The model is a simple model, but an estimation model can be created to suit the system.

[0157] Alternatively, a heating element may be placed between the sensor and the battery for closed-loop control, followed by model prediction and measurement. Furthermore, internal parameters can be estimated from the control value, heat flow, temperature response, etc., and R1, C1, and the distance to the heat source can be estimated, allowing for more detailed detection of the impact of degradation, etc. Since information on R1 and C1 can be obtained, measurements that are resistant to disturbances (individual differences and aging) become possible.

[0158] 1: Information processing system, 2: Power storage device, 3: Signal processing system, 4: Information processing device, 6: Temperature adjustment element, 21: Housing, 22: Power storage section, 31: Thermoelectric conversion section, 32: Heat bath, 33: First heat conduction section, 34: Second heat conduction section, 35: Signal processing circuit, 36: Switch, 40: Communication bus, 41: Communication section, 42: Memory section, 43: Processor, 44: Display section, 45: Input section, 311: First region, 312: Second region, 331: Main surface section, 332: Protrusion section, 341: Contact section, 342: Heat transport section, 351: Comparison section, 352: A C / DC converter, 353: capacitor, 431: acquisition unit, 432: detection unit, 433: determination unit, 434: change unit, 435: estimation unit, 436: device control unit, 437: display processing unit, BS: power storage system, BU: power storage unit, C1: heat capacity, D1: first direction, D2: second direction, D3: third direction, E: thermoelectromotive force, J: temperature gradient, M: thermal circuit model, M1: driving device, P: required power, Pmax: maximum output power, Q: heat source, R1: thermal resistance, Tb: reference temperature, Td: detected temperature, Vt1: threshold voltage, ΔT: temperature difference

Claims

1. An information processing system, It comprises a thermoelectric conversion unit and a signal processing unit, The thermoelectric conversion unit is configured to generate a temperature gradient through heat exchange with the equipment, and to generate a thermoelectric voltage based on this temperature gradient. The signal processing unit comprises an acquisition unit and a detection unit, The acquisition unit is configured to acquire the thermoelectric power, The detection unit is configured to detect abnormal operation of the equipment accompanied by heat generation based on the thermoelectric voltage.

2. An information processing system, It comprises a thermoelectric conversion unit and a signal processing unit, The thermoelectric conversion unit is configured to generate a thermoelectric voltage in accordance with the temperature gradient generated in the thermoelectric conversion unit by heat exchange with the equipment. The signal processing unit comprises an acquisition unit and an equipment control unit, The acquisition unit is configured to acquire the thermoelectric power, The equipment control unit is configured to control the operation of the equipment based on the acquired thermoelectric power.

3. In the information processing system according to claim 1 or 2, The thermoelectric conversion unit is configured to generate the thermoelectric voltage, which includes a component that occurs in a direction different from the temperature gradient.

4. In the information processing system according to claim 1 or 2, Furthermore, it is equipped with a first heat conduction section, The first heat conduction unit connects the equipment and the thermoelectric conversion unit.

5. In the information processing system described in claim 4, The first heat conduction portion includes a protrusion, The protruding portion is configured to protrude from the device when the device is viewed in plan from a predetermined first direction. The thermoelectric conversion unit is connected to the protruding portion.

6. In the information processing system according to claim 1 or 2, Furthermore, it is equipped with a second heat conduction section, The thermoelectric conversion unit includes a first region where heat exchange with the equipment takes place, and a second region located in the direction of the temperature gradient from the first region. The second heat conduction part is connected to the second region.

7. In the information processing system described in claim 6, The second heat conduction section is connected to a temperature control section capable of adjusting the temperature of the second heat conduction section.

8. In the information processing system described in claim 6, The second heat conduction section includes a heat dissipation section capable of dissipating at least a portion of the heat that flows into the thermoelectric conversion section through the heat exchange.

9. In the information processing system described in claim 6, The second heat conduction section is connected to a heat bath at a predetermined reference temperature, thereby maintaining the temperature of the second region at approximately that reference temperature.

10. In the information processing system described in claim 9, The signal processing unit further comprises a comparison unit and a modification unit, The comparison unit is configured to compare the first signal resulting from the thermoelectric voltage of the thermoelectric conversion unit with a predetermined reference value. The modification unit is configured to change the operation of the device based on the comparison result of the first signal.

11. In the information processing system according to claim 1 or 2, The aforementioned device is an energy storage device capable of charging and discharging electricity, The signal processing unit further comprises a first estimation unit, The acquisition unit is configured to acquire information relating to the second signal output from the energy storage device, The first estimation unit is configured to estimate the charge state or health state of the energy storage device based on the output history of the second signal and the thermoelectric power.

12. In the information processing system according to claim 1 or 2, The thermoelectric conversion unit is configured such that the thermoelectric voltage changes in response to the temperature change of the surface of the device due to heat generation. The signal processing unit further comprises a second estimation unit, The second estimation unit is configured to estimate the positional information of the heat-generating location of the equipment relative to the surface of the equipment, based on a predetermined heat conduction model of the equipment and the surface temperature of the equipment based on the thermoelectric power.

13. In the information processing system according to claim 1 or 2, Furthermore, the device includes the aforementioned equipment.

14. Information processing method, The following steps are included: In the thermoelectric conversion step, a thermoelectric voltage is generated in accordance with the temperature gradient created in the thermoelectric conversion section by heat exchange with the equipment, and here, the equipment is configured to generate heat according to its operating state. The determination step determines the operating state of the device according to the thermoelectric power.

15. Information processing method, The following steps are included: In the thermoelectric conversion step, a temperature gradient is generated by heat exchange with the equipment, and a thermoelectric voltage is generated based on this temperature gradient. In the acquisition step, the thermoelectric power is acquired. A method for detecting abnormal operation of the equipment accompanied by heat generation, based on the thermoelectric voltage, in the detection step.