Thermal management system for sodium electricity energy storage device and energy storage station

Abstract

The invention relates to a thermal management system for a sodium electricity energy storage device and an energy storage station, and the thermal management system comprises an overground heat exchanger which is arranged in the sodium electricity energy storage device; the overground temperature sensor is arranged in the sodium electricity energy storage device; the underground heat exchangers can be dispersedly buried under the ground of a site where the sodium electricity energy storage device is located; the plurality of underground temperature sensors can be buried underground and are adjacent to the plurality of underground heat exchangers one by one; the control pipeline is connected with the ground heat exchanger and each underground heat exchanger, and comprises a control valve group and a driving pump; and the control unit is electrically connected with the control valve group, the driving pump, the overground temperature sensor and the underground temperature sensors. The thermal management system can perform effective thermal management on the sodium electricity energy storage device, has the advantages of energy conservation, high efficiency, low cost, compact size and the like, and facilitates promotion of popularization and application of the sodium electricity energy storage device.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of energy storage stations. More specifically, the present invention relates to a thermal management system and an energy storage station for a sodium electric energy storage device. Background Art

[0002] With the vigorous development of renewable energy around the world, energy storage technology has become a key pillar of energy transformation. Among them, sodium-ion energy storage devices are increasingly attracting widespread attention in the industry due to their advantages of low cost, high safety and long cycle life, and are regarded as a highly promising next-generation large-scale energy storage solution. However, as the core component of sodium-ion energy storage devices, sodium-ion battery packs generate a lot of heat during the charging and discharging process. If the heat accumulation is not effectively controlled, it will directly threaten the performance stability and cycle life of the sodium-ion battery pack, and may even cause catastrophic safety accidents. Therefore, effective thermal management is crucial for sodium-ion energy storage devices.

[0003] At present, existing thermal management technologies are largely customized for lithium-ion energy storage devices. Taking cooling as an example, the system usually relies too much on air cooling and / or liquid cooling technology, or even simply superimposes geothermal utilization technology on the two. Admittedly, although this system has excellent temperature control performance, when it is directly copied and applied to sodium-ion energy storage devices, it is bloated and overpowered, which not only causes serious energy waste, but also significantly increases the overall cost of sodium-ion energy storage devices.

[0004] Therefore, in order to truly bring into play the advantages of sodium battery energy storage devices, it is urgent to break through the constraints of existing lithium battery thermal management thinking and innovatively develop a thermal management system designed specifically for the characteristics of sodium battery energy storage devices. This new system must achieve a comprehensive leap in energy saving, high efficiency, cost-effectiveness and compactness to promote the popularization and application of sodium battery energy storage devices. Summary of the invention

[0005] In order to solve one or more of the technical problems mentioned above, the present invention provides a thermal management system and an energy storage station for a sodium-electric energy storage device. The thermal management system can effectively manage the thermal state of the sodium-electric energy storage device and has the advantages of energy saving, high efficiency, low cost and compact size, which is conducive to promoting the popularization and application of sodium-electric energy storage devices.

[0006] According to a first aspect of the present invention, there is provided a thermal management system for a sodium-based energy storage device, comprising: an above-ground heat exchanger disposed within the sodium-based energy storage device; an above-ground temperature sensor disposed within the sodium-based energy storage device; a plurality of underground heat exchangers that can be dispersedly buried underground at the site where the sodium-based energy storage device is located; a plurality of underground temperature sensors that can be buried underground and are adjacent to the plurality of underground heat exchangers one by one; a control pipeline connected to the above-ground heat exchanger and each of the underground heat exchangers, and comprising a control valve group and a driving pump; and a control unit electrically connected to the control valve group, the driving pump, the above-ground temperature sensor, and each of the underground temperature sensors. The control unit is configured to: based on the detection results of the above-ground temperature sensor and each of the underground temperature sensors, start and stop the driving pump and switch the working state of the control valve group, so as to alternately select one of the plurality of underground heat exchangers as a selected object to be connected to the above-ground heat exchanger, such that the heat exchange medium can be driven by the driving pump and circulate between the selected object and the above-ground heat exchanger.

[0007] According to a second aspect of the present invention, there is provided an energy storage station, comprising a sodium-based energy storage device and the thermal management system as described in the first aspect of the present invention.

[0008] In the thermal management system and the energy storage station mentioned above, by skillfully combining the above-ground heat exchanger, the underground heat exchanger, and the control pipeline, cooling or heating of the sodium-based energy storage device using geothermal energy is achieved. Further, by using the above-ground temperature sensor and the underground temperature sensor to continuously monitor the temperature changes of the sodium-based energy storage device and underground, it is ensured that the control unit can automatically adjust the cooling or heating strategy of the thermal management system for the sodium-based energy storage device according to the detection results. In this way, not only can the sodium-based energy storage device, especially the sodium-ion battery pack, be efficiently cooled using geothermal energy in hot seasons, but also it can be heated using geothermal energy in cold seasons, ensuring that the sodium-ion battery pack operates within the optimal temperature range, thereby improving the performance stability and cycle life of the battery and avoiding safety accidents caused by heat accumulation. At the same time, since the above-ground heat exchanger and the above-ground temperature sensor are disposed inside the sodium-based energy storage device, while the underground heat exchanger and the underground temperature sensor are buried underground, it is not necessary to use relatively large air-cooling and liquid-cooling equipment on the ground as in the prior art. In this way, the thermal management system can effectively reduce the occupation of the ground and avoid the bulkiness of the energy storage station. It can be seen that the present invention not only effectively solves many defects in the thermal management of the sodium-based energy storage device, but also realizes a comprehensive improvement in aspects such as energy conservation, efficiency, cost-effectiveness, and volume compactness of the system, providing a solid technical support for the popularization and application of the sodium-based energy storage device. Description of the Drawings

[0009] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present invention will become readily understandable. In the drawings, several embodiments of the present invention are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein: Figure 1 This is a usage state diagram of the thermal management system for a sodium battery energy storage device according to an embodiment of the present invention; Figure 2 is Figure 1 The front view of the first underground heat exchanger of the shown thermal management system; Figure 3 is Figure 2 The top view of the first underground heat exchanger shown; Figure 4 is Figure 2 The cross-sectional view of the liquid outlet section of the spiral tube of the first underground heat exchanger shown.

[0010] Explanation of reference numerals: 1, above-ground heat exchanger; 21, first underground heat exchanger; 22, second underground heat exchanger; 23, third underground heat exchanger; 31, first underground temperature sensor; 311, spiral tube; 312, core column; 3112, heat exchange rib; 31a, liquid inlet section; 31b, liquid outlet section; 31c, cylindrical spiral section; 32, second underground temperature sensor; 33, third underground temperature sensor; 4, control pipeline; 411, first reversing valve; 412, second reversing valve; 42, driving pump; 5, above-ground temperature sensor; 7, heat insulation material; 100, thermal management system; 200, sodium battery energy storage device; 2001, sodium ion battery pack. Detailed implementation manners

[0011] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present disclosure.

[0012] Figure 1 This is a usage state diagram of the thermal management system for a sodium battery energy storage device according to an embodiment of the present invention; As Figure 1As shown in the figure, an embodiment of the present invention provides a thermal management system 100 for a sodium battery energy storage device 200. The thermal management system 100 includes: an above-ground heat exchanger 1 disposed within the sodium battery energy storage device 200, a plurality of underground heat exchangers (such as a first underground heat exchanger 21, a second underground heat exchanger 22, and a third underground heat exchanger 23) buried underground in the site where the sodium battery energy storage device 200 is located, and a control pipeline 4 connecting the above-ground heat exchanger 1 and each underground heat exchanger. Among them, the above-ground heat exchanger 1 is disposed within the sodium battery energy storage device 200, preferably within or on the surface of the sodium ion battery pack 2001 of the sodium battery energy storage device 200, to ensure that the heat exchange medium (water or oil) flowing through it can cool or heat the interior of the sodium battery energy storage device 200. The plurality of underground heat exchangers can be dispersed and buried underground in the site where the sodium battery energy storage device 200 is located, so that the heat exchange medium (water or oil) flowing through them can exchange heat with the soil in different regions, thereby utilizing geothermal energy. The control pipeline 4 includes a control valve group (such as a first reversing valve 411 and a second reversing valve 412) and a driving pump 42. The control valve group can alternately select one of the plurality of underground heat exchangers as the selected object to be connected to the above-ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the selected object and the above-ground heat exchanger 1.

[0013] It should be emphasized that although Figure 1 only one above-ground heat exchanger 1 and one sodium ion battery pack 2001 are shown, this should not be construed as a limitation on the protection scope of the present invention. In addition to including one above-ground heat exchanger 1 and being adapted to a sodium battery energy storage device 200 with only one sodium ion battery pack 2001, the thermal management system 100 of the embodiment of the present invention can also include a plurality of above-ground heat exchangers connected in series and be adapted to a sodium battery energy storage device 200 with a plurality of sodium ion battery packs 2001.

[0014] The thermal management system 100 further includes: a ground temperature sensor 5 disposed within the sodium battery energy storage device 200, a plurality of underground temperature sensors (such as a first underground temperature sensor 31, a second underground temperature sensor 32, and a third underground temperature sensor 33) buried underground and adjacent to a plurality of underground heat exchangers one by one, and a control unit electrically connected to the control valve group, the driving pump 42, the ground temperature sensor 5, and each underground temperature sensor. Among them, the ground temperature sensor 5 is used to detect the internal temperature of the sodium battery energy storage device 200, and preferably is disposed within or on the surface of the sodium ion battery pack 2001 of the sodium battery energy storage device 200 to ensure that the ground temperature sensor 5 can directly detect the temperature of the sodium ion battery pack 2001. The plurality of underground temperature sensors are used to detect the soil temperature in the area where the closest underground heat exchanger is located. The control unit is configured to: based on the detection results of the ground temperature sensor 5 and each underground temperature sensor, open and close the driving pump 42 and switch the working state of the control valve group, so as to alternately select one of the plurality of underground heat exchangers as the selected object to be connected to the ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the selected object and the ground heat exchanger 1.

[0015] In terms of specific implementation manners, the aforementioned control unit of the present invention generally includes a processor (such as a CPU), a memory, and electronic components connected to the processor, etc., which are well-known to those skilled in the art and will not be elaborated here. It should be noted that the number of the processor, the memory, and the necessary electronic components is not limited and can be adjusted according to actual needs. For example, when the control unit needs to be disassembled into multiple control modules, the multiple control modules respectively execute different tasks of the control unit and communicate and cooperate to complete one or more tasks when necessary.

[0016] Next, in combination with Figure 1 and Figure 2Describe the usage process of the thermal management system 100 of this embodiment. In the hot season, when the driving pump 42 is started, the heat exchange medium begins to circulate in the thermal management system 100. The relatively hot heat exchange medium first flows through the above-ground heat exchanger 1, and its temperature rises after absorbing the heat dissipated by the sodium-ion battery pack 2001. Subsequently, the heated heat exchange medium pushed by the driving pump 42 enters the pre-selected underground heat exchanger, where the heat exchange medium releases the heat to the relatively low-temperature soil, and its own temperature decreases accordingly. The cooled heat exchange medium is sent back to the above-ground heat exchanger 1 by the driving pump 42 again, and this cycle continues, continuously exporting the heat of the sodium-ion battery pack 2001 to the underground, thereby achieving temperature reduction and ensuring the efficient operation of the sodium-ion battery pack 2001 at a suitable temperature. In the cold season, when the driving pump 42 is started, the heat exchange medium also begins to circulate, but at this time it first flows through the pre-selected underground heat exchanger. Since the underground soil temperature is relatively high, the heat exchange medium absorbs heat from the soil and its own temperature rises. Then, the heated heat exchange medium driven by the driving pump 42 reaches the above-ground heat exchanger 1 and releases the heat to the relatively low-temperature sodium-ion battery pack 2001 here, providing heat for it. After releasing heat, the heat exchange medium is sent back to the underground heat exchanger by the driving pump 42 again, continuously absorbing heat from the soil and transferring it to the sodium-ion battery pack 2001, and this cycle continues, achieving the purpose of heating the sodium-ion battery pack 2001 and ensuring the efficient operation of the sodium-ion battery pack 2001 at a suitable temperature.

[0017] In the present invention, by cleverly combining the above-ground heat exchanger 1, the underground heat exchanger and the control pipeline 4, it aims to utilize geothermal energy to cool or heat the sodium-based energy storage device 200. Then, through the above-ground temperature sensor 5 and the underground temperature sensor, the temperature changes of the sodium-based energy storage device 200 and underground are monitored in real time, so as to ensure that the control unit can automatically adjust the cooling or heating strategy of the thermal management system 100 for the sodium-based energy storage device 200 according to the detection results. In this way, not only can the sodium-based energy storage device 200, especially the sodium-ion battery pack 2001, be efficiently cooled in the hot season by means of geothermal energy, but also it can be heated by means of geothermal energy in the cold season, ensuring that the sodium-ion battery pack 2001 works within the optimal temperature range, thereby improving the performance stability and cycle life of the sodium-ion battery pack 2001 and avoiding safety accidents caused by heat accumulation. At the same time, since the above-ground heat exchanger 1 and the above-ground temperature sensor 5 are arranged inside the sodium-based energy storage device 200, while the underground heat exchanger and the underground temperature sensor are buried underground, it is not necessary to use relatively large air-cooling and liquid-cooling equipment on the ground as in the prior art. In this way, the thermal management system 100 can effectively reduce the occupation of the ground and avoid the bulkiness of the energy storage station volume. It can be seen that the present invention not only effectively solves many defects of the sodium-based energy storage device 200 in thermal management, but also realizes the comprehensive improvement of the system in terms of energy conservation, high efficiency, cost-effectiveness and volume compactness, providing a solid technical support for the popularization and application of the sodium-based energy storage device 200.

[0018] As an example, multiple underground heat exchangers include a first underground heat exchanger 21, a second underground heat exchanger 22, and a third underground heat exchanger 23. Correspondingly, the control valve group has a first working state, a second working state, and a third working state. In the first working state, the control valve group connects the first underground heat exchanger 21 to the above-ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the first underground heat exchanger 21 and the above-ground heat exchanger 1. In the second working state, the control valve group connects the second underground heat exchanger 22 to the above-ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the second underground heat exchanger 22 and the above-ground heat exchanger 1. In the third working state, the control valve group connects the third underground heat exchanger 23 to the above-ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the third underground heat exchanger 23 and the above-ground heat exchanger 1. By setting multiple underground heat exchangers and multiple working states of the control valve group, the underground heat exchangers at different locations can be flexibly used according to actual needs. For example, different underground heat exchangers can be used alternately to allow the soil time to recover its temperature. For another example, the underground heat exchanger with the best heat exchange effect with the above-ground heat exchanger 1 can be selected to achieve a more efficient thermal management strategy.

[0019] To adapt to the first underground heat exchanger 21, the second underground heat exchanger 22, and the third underground heat exchanger 23 and accurately obtain the soil temperature in their respective areas, multiple underground temperature sensors may include a first underground temperature sensor 31, a second underground temperature sensor 32, and a third underground temperature sensor 33 that are sequentially used to detect the soil temperature near the first underground heat exchanger 21, the second underground heat exchanger 22, and the third underground heat exchanger 23.

[0020] To ensure that the control unit automatically controls the start and stop of the driving pump 42 and the working state of the control valve group according to the detection results of the above-ground temperature sensor 5 and the underground temperature sensors, so as to achieve temperature regulation of the sodium battery energy storage device 200. The control unit is configured to: in response to T0 [T0', T0"], start the driving pump 42, and start the first working state, the second working state, or the third working state of the control valve group when the thermal management system 100 is started for the first time, and restore the working state used by the control valve group at the end of the previous operation when the thermal management system 100 is started subsequently; in response to T0 [T0', T0"], stop the driving pump 42. Then, the control unit is further configured to, when the control valve group is in the first working state: in response to |T0 - T1| > T, maintain the control valve group in the first working state; in response to |T0 - T1| ≤ T, and |T0 - T2| > T, control the control valve group to switch to the second working state; in response to |T0 - T1| ≤ T, |T0 - T2| ≤ T, and |T0 - T3| > T, control the control valve group to switch to the third working state; in response to |T0 - T1| ≤ T, |T0 - T2| ≤ T, and |T0 - T3| ≤ T, maintain the control valve group in the first working state. Then, the control unit is further configured to, when the control valve group is in the second working state: in response to |T0 - T2| > T, maintain the control valve group in the second working state; in response to |T0 - T2| ≤ T, and |T0 - T3| > T, control the control valve group to switch to the third working state; in response to |T0 - T2| ≤ T, |T0 - T3| ≤ T, and |T0 - T1| > T, control the control valve group to switch to the first working state; in response to |T0 - T2| ≤ T, |T0 - T3| ≤ T, and |T0 - T1| ≤ T, maintain the control valve group in the second working state. Then, the control unit is further configured to, when the control valve group is in the third working state: in response to |T0 - T3| > T, maintain the control valve group in the third working state; in response to |T0 - T3| ≤ T, and |T0 - T1| > T, control the control valve group to switch to the first working state; in response to |T0 - T3| ≤ T, |T0 - T1| ≤ T, and |T0 - T2| > T, control the control valve group to switch to the second working state; in response to |T0 - T3| ≤ T, |T0 - T1| ≤ T, and |T0 - T2| ≤ T, maintain the control valve group in the third working state. Wherein: T0 is the detection result of the above-ground temperature sensor 5, in °C; T0' and T0" are respectively the upper limit value (for example, 10 °C) and the lower limit value (for example, 28 °C) of the set temperature range, in °C; T1 is the detection result of the first underground temperature sensor 31, in °C; T2 is the detection result of the second underground temperature sensor 32, in °C; T3 is the detection result of the third underground temperature sensor 33, in °C; T is the set temperature difference threshold (for example, 3, 4, or 5), in °C.

[0021] Through the above control logic, the control unit can compare the temperature differences between the soil temperatures around different underground heat exchangers and the temperature of the sodium battery energy storage device 200 based on the real-time temperature monitoring data, automatically start and stop the driving pump 42 and switch the working states of the control valve group, and select the underground heat exchanger with higher current heat exchange efficiency to better control the temperature of the sodium battery energy storage device 200 within the set optimal temperature range, ensuring the performance stability and cycle life of the sodium ion battery pack 2001.

[0022] In this embodiment, in addition to two three-position four-way directional control valves, the control valve group can also adopt more valves to implement corresponding control. Any method that can meet the requirements of the three working states of the control valve group falls within the protection scope claimed by the present invention. Taking the embodiment of two three-position four-way directional control valves as an example, the control valve group includes a first directional control valve 411 and a second directional control valve 412. Among them, the first directional control valve 411 includes a first working port, a second working port, and a third working port that are sequentially connected to the inlet of the first underground heat exchanger 21, the inlet of the second underground heat exchanger 22, and the inlet of the third underground heat exchanger 23, and a fourth working port connected to the outlet of the above-ground heat exchanger 1; the second directional control valve 412 includes a fifth working port, a sixth working port, and a seventh working port that are sequentially connected to the outlet of the first underground heat exchanger 21, the outlet of the second underground heat exchanger 22, and the outlet of the third underground heat exchanger 23, and an eighth working port connected to the inlet of the above-ground heat exchanger 1. Among them, the driving pump 42 is arranged between the above-ground heat exchanger 1 and the first directional control valve 411, or between the above-ground heat exchanger 1 and the second directional control valve 412. When the control valve group is in the first working state, the first directional control valve 411 is in its first working condition. For example, through the actuator of the first directional control valve 411, the spool inside the first directional control valve 411 moves to a specific position, connecting the fourth working port to the first working port. At the same time, the second directional control valve 412 is also in its first working condition and uses a similar principle to connect the eighth working port to the fifth working port. At this time, the first directional control valve 411 and the second directional control valve 412 cooperate to connect the first underground heat exchanger 21 to the above-ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the first underground heat exchanger 21 and the above-ground heat exchanger 1. When the control valve group is in the second working state, the first directional control valve 411 is in its second working condition and connects the fourth working port to the second working port, and the second directional control valve 412 is also in its second working condition and connects the eighth working port to the sixth working port. At this time, the first directional control valve 411 and the second directional control valve 412 cooperate to connect the second underground heat exchanger 22 to the above-ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the second underground heat exchanger 22 and the above-ground heat exchanger 1. When the control valve group is in the third working state, the first directional control valve 411 is in its third working condition and connects the fourth working port to the third working port, and the second directional control valve 412 is also in its third working condition and connects the eighth working port to the seventh working port. At this time, the first directional control valve 411 and the second directional control valve 412 cooperate to connect the third underground heat exchanger 23 to the above-ground heat exchanger 1, so that the heat exchange medium can be driven by the driving pump 42 and circulate between the third underground heat exchanger 23 and the above-ground heat exchanger 1.

[0023] As an example, such as Figure 2 and Figure 3As shown, each of the underground heat exchangers represented by the first underground heat exchanger 21, the second underground heat exchanger 22, and the third underground heat exchanger 23 may include an inlet liquid section 31a, an outlet liquid section 31b, and a cylindrical spiral section 31c. The inlet liquid section 31a is connected to the top of the cylindrical spiral section 31c and is connected to the control pipeline 4 after extending out of the ground of the aforementioned site (the site where the sodium battery energy storage device 200 is located). The outlet liquid section 31b is connected to the bottom of the cylindrical spiral section 31c and is connected to the control pipeline 4 after extending out of the ground of the aforementioned site. Since the cylindrical spiral section 31c is buried underground as the main heat exchange part and has a large area of contact with the soil, it can make the most of the underground space for heat exchange. The inlet liquid section 31a and the outlet liquid section 31b ensure the smooth inlet and outlet of the heat exchange medium to and from the cylindrical spiral section 31c and facilitate the connection with the control pipeline 4.

[0024] Preferably, the cylindrical spiral sections 31c of the first underground heat exchanger 21, the second underground heat exchanger 22, and the third underground heat exchanger 23 are buried at a depth of 10m - 30m underground. The orthographic projections of the central axes of the first underground heat exchanger 21, the second underground heat exchanger 22, and the third underground heat exchanger 23 on the ground of the aforementioned site form the three vertices of an equilateral triangle, and the orthographic projection of the central axis of the sodium battery energy storage device 200 on the ground of the aforementioned site falls within the equilateral triangle. Since the soil temperature at a depth of 10m - 30m is relatively stable, less affected by the surface temperature fluctuations, and closer to the geothermal constant temperature layer, it can ensure that each underground heat exchanger can utilize a stable ground temperature (16°C - 22°C), and at the same time take into account the economy and feasibility of burial. That is, if it is too shallow, it may be greatly affected by the surface temperature, and if it is too deep, the burial cost will be relatively high. At the same time, since the first underground heat exchanger 21, the second underground heat exchanger 22, and the third underground heat exchanger 23 are arranged in an equilateral triangle, they can be relatively evenly distributed in the underground area around the sodium battery energy storage device 200, so as to make more full and uniform use of the geothermal resources underground in the site.

[0025] In Figure 2 and Figure 4In the preferred embodiment shown, each underground heat exchanger includes a spiral tube 311 having an inlet and an outlet, a core column 312 inserted into the spiral tube 311 along the extension direction of the spiral tube 311, and a flow-through channel formed between the spiral tube 311 and the core column 312 and communicating the inlet and the outlet of the spiral tube 311. Among them, the spiral tube 311 includes a tube body 3111 and a plurality of heat exchange ribs 3112 arranged at intervals along the circumference and fixedly provided on the inner wall of the tube body 3111. The plurality of heat exchange ribs 3112 are used to fix the core column 312 in the tube body 3111. Among them, each heat exchange rib 3112 extends from the inlet of the spiral tube 311 along the flow-through channel to the outlet of the spiral tube 311. When in use, the heat exchange medium flows in from the inlet of the spiral tube 311, flows spirally in the flow-through channel between the spiral tube 311 and the core column 312, exchanges heat with the tube body 3111 of the spiral tube 311 and the heat exchange ribs 3112, and then flows out from the outlet of the spiral tube 311. Due to the spiral structure of the spiral tube 311, the occupation of the core column 312, and the enhanced heat exchange effect of the heat exchange ribs 3112, the underground heat exchanger can efficiently exchange heat with the surrounding soil.

[0026] In order to consider the comprehensive requirements such as the heat exchange performance, corrosion resistance, mechanical strength, cost, and processing performance of the underground heat exchanger, and achieve the best match between the material performance and the functional requirements, the spiral tube 311 can be made of stainless steel or copper tube, and the core column 312 can be made of resin or rubber, thereby ensuring the long-term stable operation and efficient heat exchange of the underground heat exchanger. As a preferred example, the spiral tube 311 is made of 304L stainless steel, and the core column 312 is made of high-density polyethylene (HDPE for short), which can triple the life of the underground heat exchanger and significantly reduce the frequency and cost of maintenance.

[0027] The thermal management system 100 further includes a thermal insulation material 7, and the thermal insulation material 7 can be selected as polyurethane foam material or sponge, etc. The thermal insulation material 7 is used to wrap the part of the control pipeline 4 exposed between the sodium battery energy storage device 200 and the ground of the aforementioned site, and is also used to wrap the part of each underground heat exchanger above the predetermined underground depth, where the value range of the predetermined underground depth is 3m - 8m, preferably 5m. When it is necessary to cool the sodium battery energy storage device 200, the thermal insulation material 7 can reduce the heat exchange between the control pipeline 4 and the upper part of the underground heat exchanger and the external environment, reduce the heat loss of the heat exchange medium during transportation, and improve the cooling efficiency. Similarly, when it is necessary to heat the sodium battery energy storage device 200, the thermal insulation material 7 can reduce the heat absorption of the control pipeline 4 and the upper part of the underground heat exchanger from the external environment, reduce the heat absorption of the heat exchange medium during transportation, and improve the heating efficiency.

[0028] In an embodiment not shown, an energy storage station is further provided, which includes the sodium-based energy storage device 200 and the thermal management system 100 mentioned above. Among them, the sodium-based energy storage device 200, as the core component of the energy storage station, is used to store and release electrical energy. The thermal management system 100 realizes efficient, intelligent, and energy-saving thermal management of the sodium-based energy storage device 200 through the ingenious combination of the ground heat exchanger 1, the underground heat exchanger, the control unit, and the optimized structural design and material selection. This energy storage station can not only make full use of geothermal resources and reduce operating energy consumption, but also improve the performance stability, cycle life, and safety of the sodium-based energy storage device 200, providing a solid technical guarantee for the large-scale application of sodium-based energy storage technology and having significant economic and social benefits.

[0029] In the above description of the present application, unless otherwise clearly specified and limited, terms such as "fixed", "installed", "connected" or "coupled" should be understood in a broad sense. For example, in the case of the term "connected", it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be the internal communication of two components or the interaction relationship between two components. Therefore, unless otherwise clearly limited in the present application, those skilled in the art can understand the specific meaning of the above terms in the present invention according to specific circumstances.

[0030] According to the above description of the present application, those skilled in the art can also understand the terms used as follows. For example, terms indicating orientation or positional relationship such as "upper", "lower", etc. are based on the orientation or positional relationship shown in the drawings of the present application. It is only for the purpose of facilitating the description of the solution of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or component involved must have the specific orientation, be constructed and operate in the specific orientation. Therefore, the above terms of orientation or positional relationship cannot be understood or interpreted as a limitation to the solution of the present invention.

[0031] In addition, the terms "first" or "second" etc. used in the present application to refer to numbers or ordinals are only for descriptive purposes and cannot be understood as explicitly or implicitly indicating relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically defined.

[0032] Although several embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many variations, modifications, and alternative forms will occur to those skilled in the art without departing from the spirit and scope of the present invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. The appended claims are intended to define the scope of the present invention and thus cover equivalents or alternatives within the scope of these claims.

Claims

1. A thermal management system for a sodium-based energy storage device, characterized in that, Comprising: An above-ground heat exchanger, which is arranged inside the sodium battery energy storage device; An above-ground temperature sensor, which is arranged inside the sodium battery energy storage device; A plurality of underground heat exchangers, which can be dispersedly buried underground in the site where the sodium battery energy storage device is located; A plurality of underground temperature sensors, which can be buried underground and are adjacent to the plurality of underground heat exchangers one by one; A control pipeline, which is connected to the above-ground heat exchanger and each of the underground heat exchangers, and includes a control valve group and a driving pump; A control unit, which is electrically connected to the control valve group, the driving pump, the above-ground temperature sensor and each of the underground temperature sensors, and is configured to: based on the detection results of the above-ground temperature sensor and each of the underground temperature sensors, start and stop the driving pump and switch the working state of the control valve group, so as to alternately select one of the plurality of underground heat exchangers as the selected object to be connected to the above-ground heat exchanger, so that the heat exchange medium can be driven by the driving pump and circulate between the selected object and the above-ground heat exchanger.

2. The thermal management system according to claim 1, wherein: The plurality of underground heat exchangers include a first underground heat exchanger, a second underground heat exchanger and a third underground heat exchanger, and the control valve group has a first working state, a second working state and a third working state. In the first working state, the control valve group connects the first underground heat exchanger to the above-ground heat exchanger; in the second working state, the control valve group connects the second underground heat exchanger to the above-ground heat exchanger; in the third working state, the control valve group connects the third underground heat exchanger to the above-ground heat exchanger.

3. The thermal management system according to claim 2, wherein: The plurality of underground temperature sensors include a first underground temperature sensor, a second underground temperature sensor and a third underground temperature sensor that sequentially detect the soil temperature near the first underground heat exchanger, the second underground heat exchanger and the third underground heat exchanger; The control unit is configured to: In response to T0 [T0', T0"], start the drive pump, and when starting the thermal management system for the first time, start the first working state, the second working state, or the third working state of the control valve group, and when starting the thermal management system subsequently, restore the working state used by the control valve group at the end of the previous operation of the thermal management system; In response to T0 [T0', T0"], turn off the drive pump; When the control valve group is in the first working state: in response to |T0 - T1| ≤ T, and |T0 - T2| > T, control the control valve group to switch to the second working state; in response to |T0 - T1| ≤ T, |T0 - T2| ≤ T, and |T0 - T3| > T, control the control valve group to switch to the third working state; When the control valve group is in the second working state: in response to |T0 - T2| ≤ T, and |T0 - T3| > T, control the control valve group to switch to the third working state; in response to |T0 - T2| ≤ T, |T0 - T3| ≤ T, and |T0 - T1| > T, control the control valve group to switch to the first working state; When the control valve group is in the third working state: in response to |T0 - T3| ≤ T, and |T0 - T1| > T, control the control valve group to switch to the first working state; in response to |T0 - T3| ≤ T, |T0 - T1| ≤ T, and |T0 - T2| > T, control the control valve group to switch to the second working state; Wherein: T0 is the detection result of the above-ground temperature sensor, in °C; T0' and T0" are respectively the upper limit and the lower limit of the set temperature range, in °C; T1 is the detection result of the first underground temperature sensor, in °C; T2 is the detection result of the second underground temperature sensor, in °C; T3 is the detection result of the third underground temperature sensor, in °C; ΔT is the set temperature difference threshold, in °C.

4. The thermal management system according to claim 2, wherein The control valve group includes a first reversing valve and a second reversing valve. The first reversing valve includes a first working port, a second working port, and a third working port that are sequentially connected to the inlet of the first underground heat exchanger, the inlet of the second underground heat exchanger, and the inlet of the third underground heat exchanger, and a fourth working port connected to the outlet of the above-ground heat exchanger. The second reversing valve includes a fifth working port, a sixth working port, and a seventh working port that are sequentially connected to the outlet of the first underground heat exchanger, the outlet of the second underground heat exchanger, and the outlet of the third underground heat exchanger, and an eighth working port connected to the inlet of the above-ground heat exchanger. When the control valve group is in the first working state, the first reversing valve is in its first working condition and connects the fourth working port to the first working port, and the second reversing valve is also in its first working condition and connects the eighth working port to the fifth working port. When the control valve group is in the second working state, the first reversing valve is in its second working condition and connects the fourth working port to the second working port, and the second reversing valve is also in its second working condition and connects the eighth working port to the sixth working port. When the control valve group is in the third working state, the first reversing valve is in its third working condition and connects the fourth working port to the third working port, and the second reversing valve is also in its third working condition and connects the eighth working port to the seventh working port. Wherein the driving pump is arranged between the above-ground heat exchanger and the first reversing valve, or between the above-ground heat exchanger and the second reversing valve.

5. The thermal management system according to claim 1, wherein Each of the underground heat exchangers includes a spiral tube having an inlet and an outlet, a core column inserted into the spiral tube along the extending direction of the spiral tube, and a flow passage formed between the spiral tube and the core column and connecting the inlet and the outlet of the spiral tube. Wherein the spiral tube includes a tube body and a plurality of heat exchange ribs arranged at intervals along the circumference and fixedly provided on the inner wall of the tube body, and the plurality of heat exchange ribs are used to fix the core column in the tube body.

6. The thermal management system according to claim 5, characterized in that, The spiral tube is made of stainless steel or copper tube, and the core column is made of resin or rubber.

7. The thermal management system according to claim 2, wherein The first underground heat exchanger, the second underground heat exchanger, and the third underground heat exchanger all include a liquid inlet section, a liquid outlet section, and a cylindrical spiral section. Wherein the liquid inlet section is connected to the top of the cylindrical spiral section and is connected to the control pipeline after extending out of the ground of the site, and the liquid outlet section is connected to the bottom of the cylindrical spiral section and is connected to the control pipeline after extending out of the ground of the site.

8. The thermal management system according to claim 7, wherein The cylindrical spiral sections of the first underground heat exchanger, the second underground heat exchanger, and the third underground heat exchanger are buried at a depth of 10m - 30m underground. The orthographic projections of the central axes of the first underground heat exchanger, the second underground heat exchanger, and the third underground heat exchanger on the ground of the site form the three vertices of an equilateral triangle, and the orthographic projection of the central axis of the sodium battery energy storage device on the ground of the site falls within the equilateral triangle.

9. The thermal management system according to claim 1, wherein The thermal management system further includes thermal insulation materials, which are used to wrap the part of the control pipeline exposed between the sodium battery energy storage device and the ground of the site, and are also used to wrap the parts of each of the underground heat exchangers above a predetermined underground depth, where the value range of the predetermined underground depth is 3m - 8m.

10. An energy storage station, characterized in that, It includes a sodium battery energy storage device and the thermal management system according to any one of claims 1 to 9.

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