Thermal battery and thermoelectric generator

Abstract

To provide a thermal battery which can be prevented from generating heat less.SOLUTION: A thermal battery 1 includes: an electrode pair group 10 in which a first electrode 20A and a second electrode 20B face each other across an electrolyte 20C in a first direction X and an electrode pair 20 which generates electromotive force between the first electrode 20A and the second electrode 20B according to a temperature change in the first electrode 20A and the second electrode 20B is laminated in the first direction X; and a flow passage 40 provided on both sides of each electrode pair 20 in the first direction X, fluid flowing in the flow passage. The flow passage 40 can flow fluid separately by switching high-temperature fluid at a higher temperature than a predetermined temperature and low-temperature fluid at a lower temperature than the predetermine temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a thermal battery and a thermoelectric power generation device including the thermal battery. [Background technology]

[0002] In recent years, clean energy sources that emit less greenhouse gases such as carbon dioxide and less harmful substances such as nitrogen oxides have been attracting attention. One example of clean energy is thermoelectric power generation, which converts thermal energy into electrical energy. One example of technology related to such thermoelectric power generation is described in Patent Document 1, the source of which is shown below.

[0003] Patent Document 1 describes a thermoelectric generator. This thermoelectric generator is formed by stacking a plurality of units each having a first electrode, a second electrode, and an electrolyte. The first electrode and the second electrode are arranged to face each other with a separator interposed therebetween, and the separator is impregnated with the electrolyte. A heater is attached to at least one of the first electrode and the second electrode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-73596 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the thermoelectric element described in Patent Document 1, a heater is provided to create a potential difference between the first electrode and the second electrode as described above. Therefore, at least one of the first electrode and the second electrode can be heated by the heater, but once heated, it is necessary to wait until it cools down before creating a further temperature difference. In addition, among multiple stacked units, the unit in the center takes longer to cool down than the outer units. Therefore, a temperature difference occurs between the units, and a difference occurs in the voltage of each unit. When units with such a voltage difference are connected in parallel, the amount of power generation decreases, so there is room for improvement in the thermoelectric element described in Patent Document 1.

[0006] Therefore, there is a demand for a thermal battery capable of suppressing the decrease in the amount of power generated, and a thermoelectric power generation device including such a thermal battery. [Means for solving the problem]

[0007] A characteristic configuration of the thermal battery of the present invention is that it comprises: a group of electrode pairs stacked along a first direction, in which a first electrode and a second electrode face each other along a first direction with an electrolyte interposed therebetween, and electrode pairs that generate an electromotive force between the first electrode and the second electrode in response to a temperature change of the first electrode and the second electrode; and a flow path provided on both sides along the first direction of each of the electrode pairs, through which a fluid can flow, the flow path being capable of switching between the flow of the fluid between a high-temperature fluid having a temperature higher than a predetermined temperature and a low-temperature fluid having a temperature lower than the predetermined temperature.

[0008] With this characteristic configuration, a high-temperature fluid and a low-temperature fluid can be switched to flow through the flow paths provided on both outer sides in the first direction of each of the multiple electrode pairs constituting the electrode pair group. This allows the temperatures of the multiple electrode pairs constituting the electrode pair group to be closer to each other, thereby reducing the difference in electromotive force between the first electrode and the second electrode of each electrode pair. Therefore, even when the electrode pairs are connected in parallel, it is possible to suppress a decrease in the amount of power generation. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration of a thermoelectric power generation device equipped with a thermal battery. [Diagram 2] FIG. 13 is a diagram showing a state in which a high-temperature fluid is supplied to a thermal battery. [Diagram 3] FIG. 2 is a diagram showing a state in which a low-temperature fluid is supplied to a thermal battery. [Figure 4] 4 is a flowchart showing a process in a thermoelectric power generation device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The thermal battery according to the present invention is configured to suppress the decrease in the amount of power generated, and the thermoelectric power generation device includes such a thermal battery. The thermal battery 1 and the thermoelectric power generation device 100 of the present embodiment will be described below. However, the thermal battery 1 and the thermoelectric power generation device 100 are not limited to the following embodiment, and various modifications are possible within the scope of the gist of the present invention.

[0011] First, a description will be given of the thermal battery 1. Fig. 1 is a diagram showing a schematic configuration of a thermoelectric power generation device 100 including the thermal battery 1. As shown in Fig. 1, the thermal battery 1 includes an electrode pair group 10 and a flow path 40.

[0012] The electrode pair group 10 of the thermal battery 1 is configured by stacking a plurality of electrode pairs 20 (four in the example of FIG. 1) and is housed in a case 30. In the following, when the four electrode pairs 20 are to be distinguished, they will be described as electrode pair 21, electrode pair 22, electrode pair 23, and electrode pair 24, and when they are not to be distinguished, they will be described as electrode pair 20. In addition, FIG. 1 shows a first direction X and a second direction Y perpendicular to the first direction X, but this is for the purpose of explaining the configuration of the thermal battery 1.

[0013] The electrode pair 20 includes a first electrode 20A, a second electrode 20B, and an electrolyte 20C. The first electrode 20A and the second electrode 20B are provided facing each other along the first direction X with the electrolyte 20C interposed therebetween. That is, the electrode pair 20 is provided in the first direction X with the first electrode 20A, the electrolyte 20C, and the second electrode 20B arranged in this order.

[0014] The first electrode 20A and the second electrode 20B have different temperature coefficients of redox potential. At least one of the first electrode 20A and the second electrode 20B contains a material that undergoes a structural phase transition and changes its redox potential in response to a temperature change (for example, a material that undergoes a structural phase transition and changes its redox potential significantly from Co-PBA (cobalt Prussian Blue complex)). The thermal battery 1 is configured to generate an electromotive force by raising or lowering the temperatures of the first electrode 20A and the second electrode 20B to generate a difference in redox potential between the first electrode 20A and the second electrode 20B.

[0015] In this embodiment, an electrolytic solution is used as the electrolyte 20C. Of course, the electrolyte 20C may be solid. The electrolytic solution of the electrolyte 20C can be appropriately selected from those used in conventional batteries. In this embodiment, as described above, the first electrode 20A and the second electrode 20B contain a material whose volume changes due to a structural phase transition, so that the first electrode 20A and the second electrode 20B can be immersed in the electrolytic solution to maintain contact between the first electrode 20A and the second electrode 20B and the electrolyte 20C even if the volume of the first electrode 20A and the second electrode 20B changes. In addition, when the electrolyte 20C is an electrolytic solution, a non-flammable aqueous electrolytic solution with a small potential window can be used because the potential is low, which can further improve safety.

[0016] Such an electrolyte can be, for example, an alkali metal salt such as sodium perchlorate (NaClO4), sodium chloride (NaCl), or lithium perchlorate (LiClO4) dissolved in a solvent such as water, propylene carbonate (PC), ethylene carbonate (EC), or diethyl carbonate (DEC).

[0017] The electrode pair group 10 is configured by stacking such electrode pairs 20 along the first direction X. In this embodiment, four electrode pairs 20, namely, electrode pair 21, electrode pair 22, electrode pair 23, and electrode pair 24, are stacked inside the case 30.

[0018] The flow channels 40 are provided on both sides of each electrode pair 20 along the first direction X. That is, each of the electrode pairs 21, 22, 23, and 24 is sandwiched between the flow channels 40 along the first direction X.

[0019] In this embodiment, the flow path 40 between two adjacent electrode pairs 20 is configured as a single common flow path. That is, as shown in FIG. 1, the flow path 40 between the electrode pair 21 and the electrode pair 22 is provided as a common flow path 41, and the flow path 40 between the electrode pair 22 and the electrode pair 23 is provided as a common flow path 42. In addition, the flow path 40 between the electrode pair 23 and the electrode pair 24 is provided as a common flow path 43. In order to distinguish from these common flow paths, the flow path 40 on the outside of the first electrode 20A in the electrode pair 21 will be referred to as an outer flow path 44, and the flow path 40 on the outside of the second electrode 20B in the electrode pair 24 will be referred to as an outer flow path 45.

[0020] The flow path 40 is configured to allow a fluid to flow through it. In this embodiment, the flow path 40 is provided so that the fluid flows through it along the second direction Y.

[0021] The flow paths 40 are provided with control valves 50 capable of changing the amount of fluid flowing through each of the flow paths 40. Specifically, the common flow path 41 is provided with a control valve 51, the common flow path 42 is provided with a control valve 52, and the common flow path 43 is provided with a control valve 53. In addition, the outer flow path 44 is provided with a control valve 54, and the outer flow path 45 is provided with a control valve 55.

[0022] The flow paths 40 are provided by branching off from an inflow side flow path 61 and joining together at an outflow side flow path 62. A fluid is supplied from a pump P to the inflow side flow path 61.

[0023] In such a flow path 40, a high-temperature fluid higher than a predetermined temperature and a low-temperature fluid lower than a predetermined temperature can be switched and flowed. In this embodiment, the high-temperature fluid is, for example, a fluid having a temperature of 50-55°C or higher, and the low-temperature fluid is, for example, a fluid having a temperature of 20-0°C or lower. This makes it possible to warm the first electrode 20A and the second electrode 20B adjacent to the flow path 40 through which the high-temperature fluid flows, and to cool the first electrode 20A and the second electrode 20B adjacent to the flow path 40 through which the low-temperature fluid flows.

[0024] Next, the thermoelectric power generation device 100 will be described. As shown in Fig. 1, the thermoelectric power generation device 100 includes a thermal battery 1, a potential difference information acquisition unit 70, a flow rate adjustment unit 75, a first communication passage 81, a second communication passage 82, a third communication passage 83, a fourth communication passage 84, a fifth communication passage 85, a sixth communication passage 86, a first valve device 91, a second valve device 92, a high-temperature fluid supply unit 93, a low-temperature fluid supply unit 94, and a pump P. Each of these functional units is constructed using hardware or software or both, with a CPU as a core member, in order to perform processing related to power generation by the thermal battery 1.

[0025] 1, the high-temperature fluid supply unit 93 corresponds to a supply source that supplies the above-mentioned high-temperature fluid. When the thermoelectric power generation device 100 is mounted on a vehicle, for example, an engine or a battery can be used as a heating source for the high-temperature fluid supply unit 93, and the coolant discharged from the engine or the battery can be used as the high-temperature fluid.

[0026] The low-temperature fluid supply unit 94 corresponds to a supply source that supplies the above-mentioned low-temperature fluid. When the thermoelectric power generation device 100 is mounted on a vehicle, for example, a chiller used in a heat exchange system mounted on the vehicle can be used as a cooling source for the low-temperature fluid supply unit 94, and a cooling liquid cooled by the chiller can be used as the low-temperature fluid.

[0027] The first communication passage 81 is provided between the high-temperature fluid supply unit 93 and the first valve device 91. This allows the first communication passage 81 to allow fluid (high-temperature fluid) to flow between the high-temperature fluid supply unit 93 and the first valve device 91.

[0028] The second communication passage 82 is provided between the second valve device 92 and the high-temperature fluid supply unit 93. This allows the second communication passage 82 to allow fluid (high-temperature fluid that has passed through the thermal battery 1) to flow between the second valve device 92 and the high-temperature fluid supply unit 93.

[0029] The third communication passage 83 is provided between the low-temperature fluid supply unit 94 and the first valve device 91. This allows the third communication passage 83 to allow fluid (low-temperature fluid) to flow between the low-temperature fluid supply unit 94 and the first valve device 91.

[0030] The fourth communication passage 84 is provided between the second valve device 92 and the low-temperature fluid supply unit 94. This allows the fourth communication passage 84 to allow fluid (low-temperature fluid that has passed through the thermal battery 1) to flow between the second valve device 92 and the low-temperature fluid supply unit 94.

[0031] The fifth communication passage 85 is provided between the first valve device 91 and the thermal battery 1. This allows the fifth communication passage 85 to allow fluid (high temperature fluid and low temperature fluid) to flow between the first valve device 91 and the thermal battery 1.

[0032] The sixth communication passage 86 is provided between the thermal battery 1 and the second valve device 92. This allows the sixth communication passage 86 to allow fluid (high-temperature fluid and low-temperature fluid that have passed through the thermal battery 1) to flow between the thermal battery 1 and the second valve device 92.

[0033] The first valve device 91 is a three-way valve having three communication holes. The three communication holes are provided to communicate with the first communication passage 81, the third communication passage 83, and the fifth communication passage 85, respectively. The first valve device 91 is configured to be switchable between a first communication state and a second communication state. In the first communication state, the first communication passage 81 and the fifth communication passage 85 are in communication with each other, and in the second communication state, the third communication passage 83 and the fifth communication passage 85 are in communication with each other.

[0034] The second valve device 92 is a three-way valve having three communication holes. The three communication holes are provided so as to communicate with the second communication passage 82, the fourth communication passage 84, and the sixth communication passage 86, respectively. The second valve device 92 is configured to be switchable between a third communication state and a fourth communication state. In the third communication state, the sixth communication passage 86 and the second communication passage 82 are in communication with each other, and in the fourth communication state, the sixth communication passage 86 and the fourth communication passage 84 are in communication with each other.

[0035] The pump P is provided in the fifth communication passage 85. In this embodiment, the pump P is provided in the fifth communication passage 85 so as to cause fluid to flow from the first valve device 91 side to the thermal battery 1 side.

[0036] The potential difference information acquiring unit 70 acquires potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in each electrode pair 20. In this embodiment, the respective electrode pairs 20 are electrode pair 21, electrode pair 22, electrode pair 23, and electrode pair 24. As described above, the electrode pair 20 is configured such that an electromotive force is generated between the first electrode 20A and the second electrode 20B in response to a temperature change, and a potential difference is generated between the first electrode 20A and the second electrode 20B in response to a temperature change. Therefore, the potential difference information acquiring unit 70 acquires potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 21, potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 22, potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 23, and potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 24. The potential difference information acquired by the potential difference information acquiring unit 70 is transmitted to the flow rate adjusting unit 75 described later.

[0037] The flow rate adjusting unit 75 adjusts the amount of fluid flowing through the thermal battery 1. The amount of fluid flowing through the thermal battery 1 is the amount of high-temperature fluid from the high-temperature fluid supply unit 93 and the amount of low-temperature fluid from the low-temperature fluid supply unit 94. As described above, in this embodiment, the first valve device 91 and the second valve device 92 are three-way valves. Therefore, the flow rate adjusting unit 75 switches between a state in which the amount of high-temperature fluid flowing through the thermal battery 1 is increased and the amount of low-temperature fluid flowing through the thermal battery 1 is reduced (reduced to zero), and a state in which the amount of high-temperature fluid flowing through the thermal battery 1 is reduced (reduced to zero) and the amount of low-temperature fluid flowing through the thermal battery 1 is increased.

[0038] When the amount of high-temperature fluid flowing through the thermal battery 1 is increased and the amount of low-temperature fluid flowing through the thermal battery 1 is reduced (reduced to zero), the first valve device 91 is set to a first communication state in which the first communication passage 81 and the fifth communication passage 85 are in a communication state, and the second valve device 92 is set to a third communication state in which the sixth communication passage 86 and the second communication passage 82 are in a communication state. This makes it possible to circulate high-temperature fluid between the high-temperature fluid supply unit 93 and the thermal battery 1.

[0039] When the amount of high-temperature fluid flowing through the thermal battery 1 is reduced (reduced to zero) and the amount of low-temperature fluid flowing through the thermal battery 1 is increased, the first valve device 91 is set to a second communication state in which the third communication passage 83 and the fifth communication passage 85 are in a communication state, and the second valve device 92 is set to a fourth communication state in which the sixth communication passage 86 and the fourth communication passage 84 are in a communication state. This makes it possible to circulate the low-temperature fluid between the low-temperature fluid supply unit 94 and the thermal battery 1.

[0040] In addition, the flow rate adjusting unit 75 controls the operation of the pump P. This makes it possible to adjust the amount of high-temperature fluid when circulating the above-mentioned high-temperature fluid, and also makes it possible to adjust the amount of low-temperature fluid when circulating the low-temperature fluid.

[0041] Furthermore, the flow rate adjusting unit 75 adjusts the amount of fluid flowing through the flow path 40 based on the potential difference information so that the difference between the potential differences of the stacked electrode pairs 20 is reduced. The potential difference information is transmitted from the potential difference information acquiring unit 70 as described above. The potential differences of the stacked electrode pairs 20 correspond to the potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 21, the potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 22, the potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 23, and the potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in the electrode pair 24. For example, when the potential difference of any one of the electrode pairs 20 is smaller than the potential difference of the other electrode pairs 20, it is assumed that the temperature change in the electrode pair 20 with the smaller potential difference is smaller than the temperature change in the electrode pair 20 with the larger potential difference.

[0042] Therefore, the flow rate adjustment unit 75 determines whether the potential difference indicated by the potential difference information transmitted from the potential difference information acquisition unit 70 is smaller than a preset threshold value, and increases the amount of fluid supplied to the electrode pair 20 having a potential difference smaller than the threshold value, or reduces the amount of fluid supplied to the electrode pair 20 having a potential difference equal to or greater than the threshold value.

[0043] As described above, the common flow path 41 of the thermal battery 1 is provided with the control valve 51, the common flow path 42 is provided with the control valve 52, and the common flow path 43 is provided with the control valve 53. In addition, the outer flow path 44 is provided with the control valve 54, and the outer flow path 45 is provided with the control valve 55.

[0044] Therefore, when the amount of fluid is to be increased, the flow rate regulator 75 increases the opening of the control valve 50 provided in the outer flow path 40 so that the amount of fluid flowing through the outer flow path 40 along the first direction X of the target electrode pair 20 increases. This increases the amount of fluid supplied to the electrode pair 20 having a smaller potential difference than the other electrode pairs 20, and can increase the temperature change of the first electrode 20A and the second electrode 20B, making it possible to increase the potential difference of the electrode pair 20. Therefore, it is possible to reduce the difference between the potential differences of the respective electrode pairs 20 provided in the thermal battery 1.

[0045] Alternatively, when the flow rate regulator 75 reduces the amount of fluid, it reduces the opening of the control valve 50 provided in the outer flow path 40 so as to reduce the amount of fluid flowing through the outer flow path 40 along the first direction X of the target electrode pair 20. This reduces the amount of fluid supplied to the electrode pair 20 having a potential difference larger than the potential difference of the other electrode pairs 20, and reduces the temperature change of the first electrode 20A and the second electrode 20B, making it possible to reduce the potential difference of the electrode pair 20. Therefore, it is possible to reduce the difference between the potential differences of the respective electrode pairs 20 provided in the thermal battery 1.

[0046] In addition, the flow rate adjustment unit 75 can be configured to compare the potential differences indicated in the potential difference information transmitted from the potential difference information acquisition unit 70, and to increase the amount of fluid supplied to the electrode pair 20 having a potential difference smaller than the potential difference of the other electrode pairs 20, or to reduce the amount of fluid supplied to the electrode pair 20 having a potential difference larger than the potential difference of the other electrode pairs 20.

[0047] In this case as well, when the amount of fluid is to be increased, the flow rate regulator 75 increases the aperture of the control valve 50 provided in the outer flow path 40 so as to increase the amount of fluid flowing through the outer flow path 40 along the first direction X of the target electrode pair 20, and when the amount of fluid is to be decreased, the flow rate regulator 75 decreases the aperture of the control valve 50 provided in the outer flow path 40 so as to decrease the amount of fluid flowing through the outer flow path 40 along the first direction X of the target electrode pair 20. This makes it possible to reduce the difference between the potential differences of the respective electrode pairs 20 provided in the thermal battery 1.

[0048] 2 shows an example in which a high-temperature fluid is supplied to the thermal battery 1. In this case, the flow rate regulator 75 transmits a first instruction to the first valve device 91 to set the first valve device 91 in a first communication state (#11). As a result, the valve body 91A of the first valve device 91 rotates so that the first communication passage 81 and the fifth communication passage 85 connected to the communication hole of the first valve device 91 communicate with each other, and the first communication passage 81 and the fifth communication passage 85 do not communicate with the third communication passage 83.

[0049] Furthermore, the flow rate adjusting unit 75 transmits a third command to the second valve device 92 to set the second valve device 92 in the third communication state (#13). As a result, the valve body 92A of the second valve device 92 rotates so that the sixth communication passage 86 connected to the communication hole of the second valve device 92 and the second communication passage 82 communicate with each other, and the sixth communication passage 86 and the second communication passage 82 do not communicate with each other and the fourth communication passage 84 does not communicate with each other.

[0050] Furthermore, the flow rate regulator 75 transmits an operation command to the pump P to operate the pump P (#15). As a result, the high-temperature fluid flows from the high-temperature fluid supply unit 93 to the thermal battery 1 via the first communication passage 81, the first valve device 91, and the fifth communication passage 85 to heat the first electrode 20A and the second electrode 20B, and the fluid that has heated the first electrode 20A and the second electrode 20B flows from the thermal battery 1 to the high-temperature fluid supply unit 93 via the sixth communication passage 86, the second valve device 92, and the second communication passage 82. Therefore, it becomes possible to heat the first electrode 20A and the second electrode 20B by the high-temperature fluid.

[0051] 3 shows an example in which a low-temperature fluid is supplied to the thermal battery 1. In this case, the flow rate regulator 75 transmits a second instruction to the first valve device 91 to set the first valve device 91 to the second communication state (#12). As a result, the valve body 91A of the first valve device 91 rotates so that the third communication passage 83 and the fifth communication passage 85 connected to the communication hole of the first valve device 91 communicate with each other, and the third communication passage 83 and the fifth communication passage 85 do not communicate with the first communication passage 81.

[0052] Furthermore, the flow rate adjusting unit 75 transmits a fourth command to the second valve device 92 to set the second valve device 92 in the fourth communication state (#14). As a result, the valve body 92A of the second valve device 92 rotates so that the sixth communication passage 86 and the fourth communication passage 84 connected to the communication hole of the second valve device 92 communicate with each other, and the sixth communication passage 86 and the fourth communication passage 84 do not communicate with the second communication passage 82.

[0053] Furthermore, the flow rate regulator 75 transmits an operation command to the pump P to operate the pump P (#15). As a result, the low-temperature fluid flows from the low-temperature fluid supply unit 94 to the thermal battery 1 via the third communication passage 83, the first valve device 91, and the fifth communication passage 85 to cool the first electrode 20A and the second electrode 20B, and the fluid after cooling the first electrode 20A and the second electrode 20B flows from the thermal battery 1 to the low-temperature fluid supply unit 94 via the sixth communication passage 86, the second valve device 92, and the fourth communication passage 84. Therefore, it is possible to cool the first electrode 20A and the second electrode 20B by the low-temperature fluid.

[0054] Furthermore, as described above, when the high-temperature fluid and the low-temperature fluid are being supplied to the thermal battery 1, the flow rate regulator 75 controls the control valve 50 so as to reduce the difference between the potential differences in the respective electrode pairs 20.

[0055] 4 is a flowchart showing the processing in the thermoelectric power generation device 100. First, the flow rate regulator 75 controls the first valve device 91, the second valve device 92, and the pump P so that one of the high-temperature fluid and the low-temperature fluid flows through the flow path 40 of the thermal battery 1. As a result, one of the high-temperature fluid and the low-temperature fluid flows through the flow path 40 (step #21). When the fluid starts to flow through the flow path 40, the potential difference information acquirer 70 acquires the potential difference information of each of the electrode pairs 20 of the thermal battery 1 (step #22).

[0056] If there is an electrode pair 20 whose potential difference is smaller than a preset threshold value (step #23: Yes), the flow rate adjustment unit 75 adjusts the amount of fluid flowing through the outer flow path 40 along the first direction X for that electrode pair 20 (step #24), and returns to step #22 to continue the process.

[0057] In step #23, if there is no electrode pair 20 whose potential difference is smaller than the preset threshold value (step #23: No), the thermal battery 1 starts discharging (step #25). If the thermal battery 1 ends discharging (step #26: Yes), the thermoelectric power generation device 100 ends the process.

[0058] In step #26, if the thermal battery 1 does not finish discharging (step #26: No) and the fluid flowing through the flow path 40 of the thermal battery 1 is not switched (step #27: No), the process returns to step #22 and continues.

[0059] In step #27, when the fluid flowing through the flow path 40 of the thermal battery 1 is switched (step #27: Yes), the flow rate regulator 75 controls the first valve device 91, the second valve device 92, and the pump P so that the other of the high-temperature fluid and the low-temperature fluid flows through the flow path 40 of the thermal battery 1 (step #28). As a result, the other of the high-temperature fluid and the low-temperature fluid flows through the flow path 40, and the process returns to step #22 and continues.

[0060] The thermoelectric power generation device 100 performs processing according to the above-described flow. This makes it possible to reduce the difference between the potential differences between the first electrode 20A and the second electrode 20B of each of the multiple electrode pairs 20 in the thermal battery 1.

[0061] Other embodiments Next, other embodiments of the thermal battery 1 and the thermoelectric power generation device 100 will be described.

[0062] In the above embodiment, the electrode pair group 10 has been described as having four electrode pairs 20 stacked along the first direction X. However, the electrode pair group 10 may be configured by stacking two or three electrode pairs 20 along the first direction X, or may be configured by stacking five or more electrode pairs 20 along the first direction X.

[0063] In the above embodiment, it has been described that the coolant discharged from the engine or the battery can be used as the high-temperature fluid, and the coolant cooled by a chiller can be used as the low-temperature fluid. However, the high-temperature fluid may be a fluid different from the coolant discharged from the engine or the battery, and the low-temperature fluid may be a fluid different from the coolant cooled by a chiller. In addition, in the above embodiment, it has been described that the thermoelectric power generation device 100 is mounted on a vehicle, but the thermoelectric power generation device 100 may be provided in, for example, a building.

[0064] In the above embodiment, the flow path 40 has been described as being provided so that the fluid flows along the second direction Y. However, the flow path 40 may be provided so that the fluid flows along a direction different from the second direction Y, i.e., a direction intersecting the second direction Y.

[0065] In the above embodiment, the flow path 40 between two adjacent electrode pairs 20 has been described as a single common flow path. However, the flow paths 40 between two adjacent electrode pairs 20 may be provided separately. In other words, two flow paths 40 may be provided between two adjacent electrode pairs 20.

[0066] [Summary of the above embodiment] The above-described thermal battery 1 and thermoelectric power generation device 100 will now be outlined.

[0067] (1) A thermal battery 1 includes an electrode pair group 10 in which electrode pairs 20 are stacked along a first direction X, where a first electrode 20A and a second electrode 20B face each other along a first direction X with an electrolyte 20C interposed therebetween, and an electrode pair 20 that generates an electromotive force between the first electrode 20A and the second electrode 20B in response to a temperature change between the first electrode 20A and the second electrode 20B, and a flow path 40 provided on both sides of each electrode pair 20 along the first direction X, through which a fluid can flow, and the flow path 40 is capable of switching between a high-temperature fluid having a temperature higher than a predetermined temperature and a low-temperature fluid having a temperature lower than the predetermined temperature.

[0068] According to this configuration, a high-temperature fluid and a low-temperature fluid can be switched to flow through the flow paths 40 provided on both outer sides in the first direction X of each of the electrode pairs 20 constituting the electrode pair group 10. This allows the temperatures of the electrode pairs 20 constituting the electrode pair group 10 to be closer to each other, thereby reducing the difference in electromotive force between the first electrode 20A and the second electrode 20B of each electrode pair 20. Therefore, even when the electrode pairs 20 are connected in parallel, it is possible to suppress a decrease in the amount of power generation.

[0069] (2) In the thermal battery 1 described in (1), it is preferable that the flow path 40 is provided so that the fluid flows along a second direction Y perpendicular to the first direction X.

[0070] According to this configuration, the fluid can be caused to flow along the electrode pair 20. Therefore, heat exchange between the electrode pair 20 and the fluid can be efficiently performed.

[0071] (3) In the thermal battery 1 described in (1) or (2), it is preferable that the flow path 40 between two adjacent electrode pairs 20 is a single common flow path.

[0072] By configuring the flow path 40 between two adjacent electrode pairs 20 as a single common flow path as in this configuration, the length of the electrode pair group 10 along the first direction X can be made shorter than in the case where separate flow paths 40 are provided between the two adjacent electrode pairs 20. Therefore, it is possible to prevent the size of the thermal battery 1 from becoming large.

[0073] (4) It is preferable that the thermoelectric power generation device 100 includes the thermal battery 1 described in (1) or (2), a potential difference information acquisition unit 70 that acquires potential difference information indicating the potential difference between the first electrode 20A and the second electrode 20B in each electrode pair 20, and a flow rate adjustment unit 75 that adjusts the amount of fluid flowing through the flow path 40 based on the potential difference information so as to reduce the difference between the potential differences of each of the stacked electrode pairs 20.

[0074] According to this configuration, it is possible to adjust the amount of fluid flowing through the flow paths 40 on both outer sides along the first direction X of the electrode pairs 20 in which the potential difference between the first electrode 20A and the second electrode 20B is small or large among the multiple electrode pairs 20 constituting the electrode pair group 10. Therefore, it is possible to adjust the temperature of the electrode pairs 20 in which the potential difference between the first electrode 20A and the second electrode 20B is small or large. [Industrial Applicability]

[0075] The technology disclosed herein can be used in a thermal battery and a thermoelectric power generation device including the thermal battery. [Explanation of symbols]

[0076] 1: thermal battery, 10: group of electrode pairs, 20: electrode pair, 20A: first electrode, 20B: second electrode, 20C: electrolyte, 40: flow path, 70: potential difference information acquisition unit, 75: flow rate adjustment unit, 100: thermoelectric power generation device, X: first direction, Y: second direction

Claims

1. a group of electrode pairs stacked along a first direction, the electrode pairs being a first electrode and a second electrode opposed to each other via an electrolyte, the electrode pairs generating an electromotive force between the first electrode and the second electrode in response to a temperature change of the first electrode and the second electrode; a flow path provided on both sides of each of the electrode pairs along the first direction, through which a fluid can flow; A thermal battery in which the flow path is capable of switching between flowing a high-temperature fluid having a temperature higher than a predetermined temperature and a low-temperature fluid having a temperature lower than the predetermined temperature.

2. The thermal battery according to claim 1 , wherein the flow path is provided so that the fluid flows along a second direction perpendicular to the first direction.

3. The thermal battery according to claim 1 or 2, wherein the flow passage between two adjacent electrode pairs is a single common flow passage.

4. The thermal battery according to claim 1 or 2; a potential difference information acquiring unit that acquires potential difference information indicating a potential difference between the first electrode and the second electrode in each of the electrode pairs; a flow rate adjusting unit that adjusts the amount of the fluid flowing through the flow path so that the difference between the potential differences of the stacked electrode pairs is reduced based on the potential difference information.

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