Temperature control system and battery storage system using the temperature control system

Abstract

To provide a temperature adjustment system that can be reduced in size and can be transported lowering the temperature while reducing losses of heat energy.SOLUTION: A temperature adjustment system according to the present invention comprises a heat energy generation unit that utilizes excess heat generated by hydrogen-adsorbing alloy adsorbing and desorbing hydrogen, and a heat transfer unit that transmits the heat of the heat energy generation unit to the object to be heated. The heat energy generation unit includes the hydrogen-adsorbing alloy, a heater that heats the hydrogen-adsorbing alloy, and a hydrogen gas in a hydrogen gas filling container, and the heat transfer unit includes a heat radiation plate whose principal plane is in contact with the heat energy generation unit and a heat receiving plate whose principal plane is in contact with the object to be heated, with an air layer included between the heat radiation plate and the heat receiving plate so that heat is conveyed by emission (radiation), enabling the heat energy of generated excess heat to be transported lowering the temperature without losses. Thus, it is made possible to provide the temperature adjustment system that may help achieve downsizing.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a temperature control system and a battery system using the temperature control system. More specifically, the present invention relates to a temperature control system that utilizes excess heat generated by a hydrogen storage alloy and a battery system using the temperature control system.

Background Art

[0002] There is known a heat generation system that utilizes excess heat generated by heating a hydrogen storage alloy to absorb and desorb hydrogen, that is, a heat generation phenomenon in which the output enthalpy is higher than the input enthalpy. (See Patent Document 1)

[0003] In addition, for electric vehicles (EVs), it is desired to increase the cruising range. If the excess heat due to the above heat generation phenomenon is utilized in a temperature control system that warms the inside of the vehicle, the seat, and further the battery during cold start, the power consumption of the temperature control system can be reduced, and the cruising range of the electric vehicle can be extended.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the heat generation phenomenon that generates the above excess heat reaches a high temperature of 500 to 1000°C, the temperature is too high as a heat source for use in heating inside the vehicle. In particular, if this excess heat is directly transmitted to the battery when warming the battery, there is a risk that the heat application will be excessive and the battery will malfunction.

[0006] Furthermore, if heat is transferred to a heat transfer medium such as a refrigerant through heat exchange, and the temperature is lowered by transporting heat through the heat transfer medium, the system itself becomes large, making it difficult to install in electric vehicles. In addition, electricity is consumed in circulating the heat transfer medium, and heat transport losses are also significant.

[0007] This invention has been made in view of the problems of the prior art, and its objective is to provide a temperature control system that can lower the temperature during transport while reducing thermal energy loss, and that can be miniaturized. [Means for solving the problem]

[0008] The inventors of this invention conducted extensive research to achieve the above objectives and discovered that the objectives can be achieved by providing an air layer between a heat dissipation plate in contact with a thermal energy generation unit that utilizes excess heat and a heat receiving plate in contact with the object to be heated, thereby transferring heat by radiation. This led to the completion of the present invention.

[0009] In other words, the temperature control system of the present invention comprises a thermal energy generation unit that utilizes excess heat generated when a hydrogen storage alloy absorbs and stores hydrogen, and a heat transfer unit that transmits the heat from the thermal energy generation unit to a heated object. Furthermore, the thermal energy generating unit comprises the hydrogen storage alloy, a heater for heating the hydrogen storage alloy, and hydrogen gas within a hydrogen gas-filled container, and the heat transfer unit comprises a heat dissipation plate whose main surface is in contact with the thermal energy generating unit and a heat receiving plate whose main surface is in contact with the object to be heated, with an air layer between the heat dissipation plate and the heat receiving plate.

[0010] Furthermore, the battery storage system of the present invention comprises the above-mentioned temperature control system and a battery storage module, wherein the battery storage module is a heated object in contact with the main surface of the heat receiving plate. [Effects of the Invention]

[0011] According to the present invention, an air layer is provided between a heat dissipation plate in contact with a heat energy generation unit that utilizes excess heat and a heat receiving plate in contact with the object to be heated, and heat is transferred by radiation. As a result, the heat energy of the generated excess heat can be transported while lowering the temperature without loss, and a miniaturized temperature control system can be provided. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view showing an example of the temperature control system of the present invention. [Figure 2] This is a schematic diagram showing an example of the battery storage system of the present invention. [Figure 3] This is a cross-sectional view of a key part showing another example of the battery storage system of the present invention. [Modes for carrying out the invention]

[0013] The temperature control system of the present invention will be described in detail. The temperature control system of the present invention comprises a thermal energy generating unit 2 and a heat transfer unit 1 that transmits the heat generated by the thermal energy generating unit to a heated object. As shown in Figure 1, this temperature control system is covered with an insulating material 3 except for the surface of the heat transfer unit that is in contact with the heated object 100.

[0014] <Heat Transfer Section> The heat transfer unit 1 has a heat sink 11 and a heat receiving plate 13. The main surface of the heat sink 11 is in contact with the heat energy generating unit 2, and the main surface of the heat receiving plate 13 is in contact with the object to be heated 100. Heat is transported in the thickness direction between these plates, and the heat energy generated by the heat energy generating unit 2 is transmitted to the object to be heated 100 to warm it.

[0015] Furthermore, an air layer 12 is provided between the heat sink 11 and the heat receiving plate 13, and heat is transferred from the heat sink 11 to the heat receiving plate 13 mainly by radiation, rather than by conduction or convection. In other words, the heat receiving plate 13 is heated by the electromagnetic waves generated by the heat sink 11, so even if the heat sink 11, which has been heated by the thermal energy generation unit 2, is at a high temperature, the heat receiving plate 13 will not immediately become at a high temperature.

[0016] Therefore, it is possible to prevent the heated object 100 from becoming high temperature due to the applied heat energy, and since it is not necessary to lower the temperature of the heat receiving plate 13 in contact with the heated object 100 by heat exchange using a heat medium such as a refrigerant, miniaturization is possible. In addition, since the surface area of the temperature control system is reduced and it is easy to block the path through which heat escapes, the transport loss of heat energy can be reduced.

[0017] Also, since the area of the main surface of the heat radiating plate 11 is larger than the contact area with the heat energy generation part 2, the heat energy from the heat energy generation part is dispersed within the heat radiating plate 11, so the temperature of the heat radiating plate 11 can be made lower than the temperature of the heat energy generation part 2.

[0018] Such a heat radiating plate 11 preferably has heat conduction anisotropy and a higher heat conductivity in the in-plane direction than in the thickness direction. Specifically, it is preferable that the heat conductivity in the in-plane direction / the heat conductivity in the thickness direction is 10 or more, and more preferably 90 or more.

[0019] Since the heat conductivity of the heat radiating plate 11 is higher in the in-plane direction than in the thickness direction, the heat energy from the high-temperature heat energy generation part 2 can be dispersed to warm a wide area, and the temperature distribution in the in-plane direction of the heat radiating plate 11 can be made uniform, preventing it from becoming locally high temperature. [[ID=**16]]

[0020] Also, if the heat receiving plate 13 also has a higher heat conductivity in the in-plane direction than in the thickness direction, similar to the heat radiating plate 11, it is possible to prevent it from becoming locally high temperature in combination with the heat radiating plate 11.

[0021] Examples of such a material having heat conduction anisotropy include a graphene sheet and a carbon nanotube sheet, and commercially available products having a heat conductivity in the in-plane direction / the heat conductivity in the thickness direction of about 1000 are available.

[0022] The heat dissipation plate 11 and the heat receiving plate 13 with higher in-plane thermal conductivity than the above-mentioned thickness direction can be manufactured by a polymer graphitization method in which graphene sheets with adjusted orientation directions described later are stacked, or by carbon nanotubes arranged in one direction.

[0023] The polymer graphitization method will be described. 1000 polyimide films as raw materials are stacked and heated to produce graphene. Then, by heating at 3000°C, the crystals are oriented in the in-plane direction. The graphene with oriented crystals is stacked to produce a graphene sheet. By further stacking the graphene sheets and applying pressure by pressing, the heat dissipation plate 11 and the heat receiving plate 13 with higher in-plane thermal conductivity than the above-mentioned thickness direction can be manufactured.

[0024] Also, as other methods, there are a method of adhering graphene sheets with the orientation direction adjusted to the in-plane direction by a conductive binder (Special Table 2019-500305), a method of manufacturing by stacking and heating a plurality of films containing graphene obtained by dispersing and mixing graphene or a dispersion liquid in a resin, applying pressure, and orienting in the in-plane direction (Patent No. 5632448), a method of manufacturing by growing multilayer graphene on the substrate surface with a graphene dispersion liquid and then applying pressure by pressing to orient in the in-plane direction (Patent No. 5728031), a method of manufacturing by stacking carbon fibers made of graphene to produce a graphene sheet, stacking a plurality of graphene sheets, heating, applying pressure, and orienting in the in-plane direction (Patent No. 5841658), etc.

[0025] Furthermore, by stacking carbon nanotubes arranged in one direction to form a sheet, it is possible to fabricate heat sinks 11 and heat receiving plates 13 with higher thermal conductivity in the in-plane direction than in the thickness direction (Anisotropic carbon nanotube papers fabricated from multiwalled carbon nanotube webs, Yoku Inoue, Yusuke Suzuki, Yoshitaka Minami, Junichi Muramatsu, Yoshinobu Shimamura, Katsunori Suzuki, Adrian Ghemes, Morihiro Okada, Shingo Sakakibara, Hidenori Mimura, Kimiyoshi Naito, Carbon 49, 2437-2443 (2012).).

[0026] The thickness of the heat sink 11 is preferably set according to the protruding length of the heat sink 11 that extends from the end of the thermal energy generating section 2, and the in-plane thermal conductivity / thickness thermal conductivity, so that the surface temperature distribution on the air layer side of the heat sink 11 is substantially uniform.

[0027] When the protruding length of the heat sink 11 is long, increasing the thickness of the heat sink 11 allows the thermal energy to be dispersed in the in-plane direction, making the surface temperature distribution on the air layer side of the heat sink 11 nearly uniform. However, by reducing the thickness of the heat sink 11 according to the thermal conductivity in the in-plane direction / thermal conductivity in the thickness direction, it is possible to achieve both a uniform temperature distribution and a reduction in heat transport loss.

[0028] Furthermore, it is preferable that the heat sink 11 and the heat receiving plate 13 have the same main surface size, and that they are arranged parallel to each other so that the end faces of the heat sink 11 and the end faces of the heat receiving plate 13 are located on the same plane. When the heat sink 11 and the heat receiving plate 13 are arranged in this manner, heat is transported uniformly from the heat sink 11 to the heat receiving plate 13, making the temperature of the heat receiving plate 13 that heats the object to be heated 100 uniform in the in-plane direction, and preventing the object to be heated 100 from becoming locally hot.

[0029] If the heat receiving plate 13 is larger than the heat sink 11, making the protrusion length of the heat receiving plate 13 from the end face of the heat sink 11 shorter than the thickness of the air layer 12 allows electromagnetic waves radiated from the heat sink 11 to reach the end of the heat receiving plate 13 more easily. This prevents a drop in the temperature at the end of the heat receiving plate 13 and reduces the difference in the temperature distribution of the heat receiving plate 13.

[0030] The emissivity (ε) of the heat sink 11 and the absorptive coefficient (α) of the heat receiving plate 13 are preferably 0.5 or higher for at least one of them, and more preferably 0.7 or higher. The emissivity (ε) and absorptivity (α) being 0.5 or higher allows for efficient heat transport between the heat sink 11 and the heat receiving plate 13.

[0031] The emissivity (ε) and absorptivity (α) mentioned above represent the emissivity (ε) and absorptivity (α) for light at a wavelength that satisfies λ = 2897 / T (μm), where the temperature (K) of the heat sink is T, and the wavelength λ (peak wavelength) at which the radiant energy obtained from the displacement side of the Wien is maximum.

[0032] Materials with an emissivity (ε) or absorptivity (α) of 0.5 or higher include metal oxides such as chromium oxide, molybdenum oxide, copper oxide, iron oxide, and nickel oxide, as well as carbon materials such as graphite, carbon nanotubes, and graphene.

[0033] Furthermore, since emissivity (ε) and absorptivity (α) vary depending on the surface condition, the heat sink and heat receiving plate only need to be formed of the above-mentioned metal oxide or carbon material on the air layer side, and the heat energy generating part 2 side of the heat sink 11 and the heated object 100 side of the heat receiving plate 13 may be formed of a material with high thermal conductivity such as metal.

[0034] Furthermore, since emissivity (ε) and absorptivity (α) can be increased by providing surface irregularities, it is preferable that the heat sink 11 has irregularities on the surface facing the air layer 12.

[0035] Emissivity can be measured using a radiation thermometer. Specifically, first, the actual temperature of the object is measured using a contact-type temperature sensor (resistance thermometer, thermocouple, etc.). Then, the object temperature is measured again with the emissivity setting value (within the range of 0.10 to 0.99) of the radiation thermometer set to an arbitrary value. The emissivity (absorptivity) can then be measured from the emissivity setting value when the temperature measured by the radiation thermometer equals the temperature measured by the contact-type temperature sensor.

[0036] <Thermal energy generation section> The thermal energy generating unit 2 generates heat and thermal energy by utilizing the exothermic phenomenon that occurs when the hydrogen storage alloy absorbs and stores hydrogen, resulting in excess heat. This thermal energy generating unit has the hydrogen storage alloy 21, a heater 22 for heating the hydrogen storage alloy, and hydrogen gas 23 inside a hydrogen gas-filled container. As shown in Figure 1, the hydrogen storage alloy 21 is positioned on the heat transfer side inside the hydrogen gas-filled container.

[0037] When the hydrogen-absorbing alloy 21, which has absorbed hydrogen, is heated by the heater 22, it releases hydrogen, and pulsed heat generation occurs when the hydrogen-absorbing alloy 21 releases hydrogen. This pulsed heat generation generates excess heat that exceeds the amount of heat used to heat the hydrogen-absorbing alloy 21.

[0038] As described above, the hydrogen storage alloy 21 generates heat at a high temperature of 500 to 1000°C. Therefore, even if the thermal energy generation unit 2 is miniaturized, a sufficient amount of heat can be obtained, and in combination with the heat transfer unit 1, the system can be miniaturized.

[0039] As the hydrogen storage alloy 21 described above, an alloy in which two solid phases coexist under desired conditions can be used. In the alloy in which the two solid phases coexist, it is preferable to use an alloy in which there is a large difference in the enthalpy of formation between the metal hydride that forms one phase and the metal hydride that forms the other phase.

[0040] Examples of alloys in which two solid phases with such large differences in enthalpy of formation coexist include Ni-Zr alloys with nickel (Ni):zirconium (Zr) in a ratio of 30:70 to 40:60 mol%, Al-Ni alloys with aluminum (Al):nickel (Ni) in a ratio of 75:25 to 65:35 mol%, and Al-Ca alloys with aluminum (Al):calcium (Ca) in a ratio of 80:20 to 70:3 mol%.

[0041] As the heater 22, a mesh-shaped heater that allows hydrogen to pass through easily and does not hinder the hydrogen absorption and storage of the hydrogen storage alloy 21 is preferably used.

[0042] The thermal energy generating unit 2, which generates excess heat, can generate excess heat again through a regeneration process. Since the hydrogen gas-filled container is equipped with a hydrogen gas supply and exhaust valve 24, the amount of hydrogen in the hydrogen gas-filled container can be adjusted to perform the regeneration process on the hydrogen storage alloy 21, and there is no need to remove the thermal energy generating unit 2 from the temperature control system for the regeneration process.

[0043] The regeneration process of the thermal energy generation unit 2 is performed by supplying hydrogen gas 23 from a hydrogen cylinder (not shown) into a hydrogen gas-filled container to increase the hydrogen gas pressure and increase the diffusion coefficient, heating the hydrogen storage alloy 21 to a temperature at which the liquid phase forms, and then holding it in a temperature range where the two phases of the hydrogen storage alloy 21 coexist to form a hydrogen storage alloy 21 in which the two phases coexist. As mentioned above, heating treatment using the heater 22 is necessary during the regeneration process, so it is desirable to cool the battery module 200 by opening the on / off valve 8 and sending outside air into the housing 9 with the blower 6.

[0044] <Temperature control system> The temperature control system may include, in addition to the heat energy generating unit 2, the heat transfer unit 1, and the insulating material 3 covering them, a temperature sensor 5 for detecting the temperature of the object to be heated 100, and a control unit 4 for controlling the heater 22 of the heat energy generating unit 2, the hydrogen gas supply and exhaust device, etc., as needed.

[0045] The control unit 4 determines whether the temperature of the object to be heated 100, as detected by the temperature sensor 5, is at an appropriate temperature. If it is below the appropriate temperature, it supplies power to the heater 22 to generate excess heat in the thermal energy generation unit 2. If it is at an appropriate temperature, it stops supplying power to the heater 22.

[0046] Furthermore, the thermal conductivity of the insulation material 3 covering the temperature control system is preferably 0.001 to 0.003 [W / m·K], and examples of such insulation materials include silica particle-filled vacuum insulation materials.

[0047] The temperature control system of the present invention can be installed in various locations within the vehicle, such as inside the seats, instrument panel, dashboard, floor, and roof, for heating the interior of the vehicle. It can also be used to warm and activate the battery during a cold start.

[0048] <Battery Storage System> The above temperature control system can be used as a battery system that has the function of warming the battery module 200 by placing it in contact with the main surface of the heat receiving plate 13 and making it the object to be heated.

[0049] The battery storage system of the present invention can not only heat the battery storage module using the above-mentioned temperature control system, but also have a cooling function.

[0050] As shown in Figure 2, the above-mentioned battery storage system houses the temperature control system and the battery storage module 200 within a housing, and the air passage 4 is located on a surface within the housing that is different from the surface of the battery storage module 200 that is in contact with the heat receiving plate 13.

[0051] Furthermore, a blower 6 is provided on the outside of the housing 9, and the airflow generated by this blower 6 is sent through piping to the air passage 7 and between the heat sink 11 and heat receiving plate 13 of the heat transfer section 1. On / off valves 8 are provided at the inlet and outlet of the air passage 7 and the heat transfer section 1, so that outside air circulates inside the housing 9 only when necessary.

[0052] The control unit 4 of the above temperature control system determines whether the temperature of the battery module 200 detected by the temperature sensor 5 is within the appropriate temperature range.

[0053] When the temperature of the battery module 200 is below the appropriate temperature range, the on-off valve 8 is closed to prevent outside air from entering the housing 9, and power is supplied to the heater 22 to generate excess heat in the thermal energy generating unit 2, thereby warming the battery module 200. When the temperature of the battery module 200 is above the appropriate temperature range, the on-off valve 8 is opened to activate the blower 6, which sends outside air into the housing 9 to cool the battery module 200.

[0054] Furthermore, when the temperature of the battery module 200 reaches the appropriate temperature range, the heater 22 and blower 6 are stopped to maintain the temperature of the battery module 200 within the appropriate temperature range.

[0055] Preferably, the battery module 200 is divided into multiple battery blocks 210. As shown in Figure 3, each divided battery block 210 is arranged in contact with the heat receiving plate 13 with a gap between them, so that an air passage 7 can be provided between adjacent battery blocks 210, improving the cooling efficiency of the battery module 200. The temperature sensor 5 may be provided in each battery block 210, or the temperature of any one battery block 210 may be used as the temperature of the battery module 200.

[0056] The air passage 7 described above can be equipped with a thermal energy generating unit 2 similar to that of the temperature control system described above. The entire surface of the thermal energy generating unit 2 is covered with an insulating material 3 so that its surface temperature is approximately 50°C, and this thermal energy generating unit 2 is positioned spaced apart from each battery block 210, as shown in Figure 3.

[0057] By providing a thermal energy generating section 2 that is entirely covered with insulating material 3, the air in the air passage 7 is heated by natural convection, and the battery block 210 can be heated from surfaces other than the surface in contact with the heat receiving plate 13 of the temperature control system without applying a large amount of thermal energy to the battery block 210, making it possible to heat the entire battery module 200 quickly. [Explanation of Symbols]

[0058] 1 Heat transfer section 11 Heat sink 12 Air layer 13 Heat receiving plate 2. Thermal energy generation unit 21 Hydrogen storage alloys 22 Heater 23 Hydrogen gas 24 Intake and exhaust valves 3. Insulation 4. Control Unit 5. Temperature sensor 6. Blower 7 Airflow channels 8. Shut-off valves 9 cabinets 100 Heated object 200 Battery Modules 210 Battery Block

Claims

1. A thermal energy generation unit that utilizes the excess heat generated when a hydrogen storage alloy absorbs and stores hydrogen, A temperature control system comprising a heat transfer unit that transmits heat from the above-mentioned thermal energy generating unit to a heated object, The above-mentioned thermal energy generating unit has the above-mentioned hydrogen storage alloy, a heater for heating the above-mentioned hydrogen storage alloy, and hydrogen gas in a hydrogen gas-filled container. A temperature control system characterized in that the heat transfer section comprises a heat dissipation plate whose main surface is in contact with the heat energy generating section and a heat receiving plate whose main surface is in contact with the object to be heated, and has an air layer between the heat dissipation plate and the heat receiving plate.

2. The temperature control system according to claim 1, characterized in that the area of ​​the main surface of the heat sink is larger than the contact area with the heat energy generating part.

3. The temperature control system according to claim 2, characterized in that the heat sink and / or heat receiving plate have thermal conductivity anisotropy and the thermal conductivity in the in-plane direction is higher than that in the thickness direction.

4. The temperature control system according to claim 3, characterized in that the end face of the heat sink and the end face of the heat receiving plate are located on the same plane.

5. The emissivity (ε) of the above heat sink is 0.5 or higher. The temperature control system according to claim 1, characterized in that the absorption rate (α) of the heat receiving plate is 0.5 or more. However, the emissivity (ε) and absorptivity (α) mentioned above are those for light of a wavelength that satisfies λ = 2897 / T (μm), where T is the temperature (K) of the heat sink, and λ is the wavelength (peak wavelength) at which the radiant energy obtained from the displacement side of the Wien is maximized.

6. The temperature control system according to claim 1, characterized in that the heat dissipation plate has irregularities on the surface facing the air layer.

7. The temperature control system according to claim 1, characterized in that the heat sink and / or heat receiving plate contains at least one selected from the group consisting of chromium oxide, molybdenum oxide, copper oxide, iron oxide, nickel oxide, graphite, carbon nanotubes, and graphene.

8. The temperature control system according to claim 1, characterized in that the heater is mesh-shaped.

9. The temperature control system according to claim 1, characterized in that the hydrogen gas-filled container is equipped with a hydrogen gas supply and exhaust valve.

10. The system includes a temperature sensor that detects the temperature of the object being heated, The temperature control system according to claim 1, characterized in that it has a control unit that operates the heater based on the temperature detected by the temperature sensor.

11. A battery storage system comprising a battery storage module and a temperature control system according to any one of claims 1 to 10, wherein the battery storage module is arranged in contact with the main surface of the heat receiving plate.

12. Furthermore, it is equipped with an air passage and a blower. The above air passage is arranged on a surface of the battery module that is different from the surface that is in contact with the heat receiving plate. The battery storage system according to claim 11, characterized in that the blower supplies air between the heat sink and the heat receiving plate, and to the air passage.

13. The battery storage system according to claim 12, characterized in that the above-mentioned battery storage module is divided into a plurality of blocks, and these blocks are arranged in contact with the main surface of the heat receiving plate at intervals.

14. The battery storage system according to claim 13, further comprising the above-mentioned thermal energy generating unit between adjacent blocks.

15. The above-mentioned battery module is equipped with a temperature sensor that detects the temperature, The battery storage system according to claim 12, characterized in that it has a control unit that operates the blower and heater based on the temperature detected by the temperature sensor.

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