Energy storage battery thermal management system based on shallow underground cold source in high-altitude severe cold area

Abstract

The utility model provides an energy storage battery thermal management system based on a shallow underground cold source in a high-altitude severe cold region, the system comprises a battery box, a liquid cooling pipeline, an air pipeline and a control system, the battery box is internally provided with a battery module, a PTC heating film, a liquid cooling plate and a phase change material; the liquid cooling pipeline takes shallow underground soil in the severe cold area as a cold source for heat dissipation through the underground liquid cooling tank; the air pipeline can introduce low-density and low-heat-conductivity-coefficient air in a high-altitude area into the interlayer of the battery box to form large thermal resistance, so that the heat insulation and heat preservation functions of the battery box are realized. According to the system, heat is provided for low-temperature preheating of the battery module through the PTC heating film and the electric heater in the liquid cooling pipeline, heat insulation and heat preservation are achieved through the air interlayer of the battery box, and rapid heating is achieved; coolant in the liquid cooling pipeline exchanges heat through the shallow underground cold source and absorbs heat of the battery module in the interlayer of the battery box and the liquid cooling plate, so that effective heat dissipation is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of thermal management of energy storage batteries, and mainly relates to a thermal management system for energy storage batteries based on a shallow underground cold source in a high-altitude severe cold area. Background Art

[0002] As a secondary energy source, rechargeable lithium-ion batteries are widely used in electrochemical energy storage systems because of their no memory, long cycle life, low self-discharge rate, and high energy density. However, temperature can seriously affect the charging and discharging performance and safety of the battery cells in the battery compartment. The suitable operating temperature range of lithium-ion batteries is 15-35°C, and when the temperature difference is within 5°C, the battery module can perform at its best overall performance. Excessively high operating temperatures can reduce the efficiency of the battery, and in severe cases can even cause thermal runaway and cause the battery to spontaneously combust, causing safety issues; low temperature environments can also reduce battery performance, especially below 0°C. Low-temperature charging can cause lithium dendrites, which can even penetrate the diaphragm in severe cases, causing internal short circuits in the battery and explosions. Based on this, it is very important to design a reasonable thermal management system for the safe and reliable operation of lithium-ion batteries in energy storage systems.

[0003] For electrochemical energy storage systems in high-altitude and cold regions, as the altitude increases, the air density gradually decreases, and the convective heat transfer capacity and the overall heat capacity of the equipment also continue to decrease. Due to the air's ground heat dissipation efficiency, the common forced air cooling system does not have an advantage under this special condition. However, the liquid cooling system has important application potential in energy storage systems in high-altitude and cold regions due to its large capacity, high rate, and high energy density.

[0004] At the same time, due to the special environmental conditions, the extreme temperature in high-altitude cold areas can reach below -25℃, and the demand for low-temperature preheating of batteries is extremely high. It is necessary not only to use high heating power technology to ensure that the battery works within a suitable temperature range, but also to pay attention to reasonable insulation treatment of the battery during the low-temperature preheating process to reduce the heat loss of the battery in a cold environment. However, it should be taken into account that battery insulation is not conducive to the heat dissipation of the liquid cooling system when the battery is working, so it is necessary to adopt a suitable technology so that the insulation function is turned on when the battery is preheated at low temperature, and the insulation function is turned off when the battery needs to be cooled. Utility Model Content

[0005] In view of this, the present utility model provides an energy storage battery thermal management system based on shallow underground cold sources in high-altitude and severe cold regions, which is used to solve the thermal management problems of rapid preheating and controllable heat preservation of energy storage batteries under low-temperature conditions in electrochemical energy storage systems under high-altitude and severe cold conditions, as well as timely cooling after the working temperature rises. Among them, the realization of the low-temperature preheating function of the energy storage battery is mainly through the PTC electric heating films on both sides of the battery; the realization of the controllable heat preservation function during the low-temperature preheating and cooling of the energy storage battery is achieved by changing the fluid in the battery box sandwich, thereby changing the thermal resistance during the heat transfer process of the energy storage battery; the realization of the cooling function after the temperature of the energy storage battery rises is mainly through the liquid cooling system to effectively dissipate heat from the battery with high cooling efficiency and low energy consumption.

[0006] To achieve the above object, the present utility model adopts the following technical solutions:

[0007] The present utility model provides an energy storage battery thermal management system based on shallow underground cold sources in high-altitude and severe cold regions, including: a battery box, a liquid cooling pipeline, an air pipeline, and a control system;

[0008] A battery module, a PTC heating film, a liquid cooling plate, and a phase change material are installed in the battery box; the battery box is a battery box sandwich with a hollow sandwich structure, and the battery box sandwich is provided with a battery box sandwich inlet and a battery box sandwich outlet; the battery module has a plurality of battery cells, and the plurality of battery cells are symmetrically and evenly distributed inside the battery box along the center of the battery box, and the battery cells are connected in series or parallel; the PTC heating film is closely attached to both sides of the battery cell; the liquid cooling plate is embedded between the single cells of the battery module; the phase change material is evenly filled in the gaps between the battery cells in the battery box;

[0009] The liquid cooling pipeline and the air pipeline are respectively connected to the battery box sandwich inlet through the battery box sandwich liquid inlet pipeline and the battery box sandwich air inlet pipeline, and the battery box sandwich outlet is respectively connected to the liquid cooling pipeline and the air pipeline through the liquid-gas separator through the liquid-gas separator liquid outlet pipeline and the liquid-gas separator gas outlet pipeline.

[0010] The control system controls the liquid cooling pipeline and the air pipeline.

[0011] Optionally, a first electric ball valve, an underground liquid cooling tank, a circulation pump, a liquid filter, and a liquid flow meter are arranged on the liquid cooling pipeline;

[0012] One end of the first electric ball valve is connected to the liquid outlet of the liquid cooling plate through the liquid cooling plate liquid outlet pipeline, and the other end is connected to the liquid cooling pipeline in the underground liquid cooling tank. One end of the circulation pump is connected to the liquid cooling pipeline arranged in the underground liquid cooling tank, and the other end is respectively connected to the liquid cooling plate liquid inlet pipeline and the battery box sandwich liquid inlet pipeline through a second electric ball valve and a third electric ball valve via the liquid filter and the liquid flow meter.

[0013] Optionally, the underground liquid cooling tank is arranged at a depth of 2 to 5 meters underground, and a liquid level gauge is provided in the underground liquid cooling tank to obtain the liquid level data of the coolant in the liquid cooling tank in real time.

[0014] Optionally, an electric heater is also provided at the inlet of the circulation pump.

[0015] Optionally, a gas-liquid separator, an environmental unit, a centrifugal pump, a gas filter, a gas flow meter, and a fourth electric ball valve are provided on the air pipeline; the fourth electric ball valve is connected to the battery box sandwich inlet through the battery box sandwich intake pipeline;

[0016] One end of the centrifugal pump is connected to the environmental unit, the other end is connected to the fourth electric ball valve via the gas filter and the gas flow meter, and the other end of the fourth electric ball valve is connected to the battery box sandwich intake pipeline.

[0017] Optionally, the control system includes a data acquisition unit, an information processing unit, and an adjustment component; the data acquisition unit includes multiple groups of temperature and pressure sensors arranged on the liquid cooling pipeline and the air pipeline.

[0018] Optionally, the surface of the PTC heating film is coated with an insulating material.

[0019] Optionally, the surface of the liquid cooling pipeline is coated with a layer of heat insulation material, and the heat insulation material is heat insulation cotton with a thickness of 10 - 40 mm.

[0020] Optionally, the coolant in the underground liquid cooling tank and the liquid cooling pipeline includes: a mixed solution of water and ethylene glycol.

[0021] Optionally, each liquid cooling plate has a liquid inlet and a liquid outlet; the flow channel structure of the liquid cooling plate is a direct current circular groove channel.

[0022] In one embodiment, when the energy storage battery is preheated in a low-temperature environment, air with a low thermal conductivity flows through the battery box sandwich, forming a large thermal resistance at the sandwich. Moreover, as the altitude increases, the density and thermal conductivity of the air gradually decrease, and the thermal resistance formed by the air in the battery box sandwich becomes larger, which can provide an effective heat insulation effect to prevent the heat of the battery from being transferred to the surrounding environment during the low-temperature preheating process. Correspondingly, when the energy storage battery generates a large amount of heat during operation and needs to dissipate heat, when a coolant fluid with a high thermal conductivity flows through the battery box sandwich, the thermal resistance of the battery box can be reduced, canceling the heat insulation effect, which is beneficial to the transfer of heat in the battery box to the environment. At the same time, the coolant liquid in the battery box sandwich can also absorb part of the heat in the battery box and actively take the heat away from the battery box.

[0023] In one embodiment, the PTC heating film is powered by an external power supply, and an adjustable transformer is used to adjust the output voltage of the external power supply to control the heating power of the PTC heating film.

[0024] In one embodiment, the phase change material is a flexible composite phase change material to reduce the contact thermal resistance between the phase change material and the battery. Its composition includes paraffin wax, styrene-ethylene-propylene-styrene, and expanded graphite. The phase change material can prevent the PTC heating film from having an excessive heating power and causing the battery to overheat during the low-temperature preheating process, and can absorb the heat of the battery pack in the form of sensible heat and latent heat during the battery heat dissipation process.

[0025] In one embodiment, the liquid cooling plate dissipates heat from the contacted battery cell, and each liquid cooling plate has an inlet and an outlet. The flow channel structure of the liquid cooling plate is a direct-current circular groove channel.

[0026] In one embodiment, the surface of the PTC heating film is coated with an insulating material to prevent leakage and short-circuit accidents caused by the melting of the phase change material. The insulating coating materials include: silicone, epoxy resin, or polyurethane / silica.

[0027] In one embodiment, the underground liquid cooling tank is arranged at a depth of 2 to 5 meters in the shallow underground. The coolant liquid in the pipe exchanges heat with the cold source of the shallow underground soil to keep the coolant liquid in the pipe at a stable low temperature. A liquid level gauge is provided in the underground liquid cooling tank to obtain the liquid level data of the coolant in the liquid cooling tank in real time, which is convenient for replenishing the coolant when the coolant in the liquid cooling tank is insufficient.

[0028] In one embodiment, the electric heater is used to heat the coolant in the liquid cooling pipeline, and the heated coolant liquid flows into the liquid cooling plate, which can provide heat for the low-temperature preheating of the battery module.

[0029] In one embodiment, the electric heater and the PTC heating film are powered by different external power supplies, and different adjustable transformers adjust the output voltage of the external power supply to prevent the two heating devices from losing their heating capabilities at the same time, resulting in the inability of the energy storage battery to perform low-temperature preheating.

[0030] In one embodiment, the gas-liquid separator can separate the liquid and gas in the battery box sandwich, and they flow back to the liquid cooling pipeline and the air pipeline respectively, realizing the switching between the gas heat preservation and heat insulation function and the liquid cooling and heat dissipation function of the battery box sandwich.

[0031] In one embodiment, the surface of the liquid cooling pipeline is coated with a layer of thermal insulation material to reduce the heat exchange between the coolant cooled by the underground liquid cooling tank and the relatively high-temperature soil on the surface layer, and the heat dissipation of the coolant in the liquid cooling pipeline heated by the electric heater to the external environment.

[0032] The beneficial effects of the present utility model are reflected in:

[0033] Multi-mode heating is achieved through the PTC heating film in the battery box and the electric heater on the liquid cooling pipeline, which can meet various requirements for low-temperature preheating of energy storage batteries in severe cold environments. At the same time, air with a low thermal conductivity coefficient flows into the battery box sandwich, increasing the thermal resistance between the battery box and the external environment, achieving the heat insulation and preservation effect of the battery box, reducing the heat dissipation from the battery box to the environment during the low-temperature preheating process, and ensuring rapid battery preheating.

[0034] In addition, the liquid cooling pipeline effectively utilizes the geographical advantages of cold regions, using the shallow underground soil in cold regions as a cold source to cool the energy storage battery, significantly reducing the energy consumption compared with the traditional energy storage system using a chiller; through the collaborative thermal management of the liquid cooling plate and the phase change material, the energy storage battery is effectively maintained within a suitable temperature range, and the temperature difference of the battery module is controlled within an ideal range; during the cooling process of the energy storage battery, a coolant liquid flows into the battery box sandwich, reducing the thermal resistance between the battery box and the environment, promoting the heat dissipation from the battery box to the environment, and further improving the cooling efficiency of the liquid cooling pipeline for the energy storage battery. Description of the Drawings

[0035] Figure 1 is a schematic diagram of the overall structure of the energy storage battery thermal management system based on the shallow underground cold source in high-altitude cold regions in an embodiment of the present application;

[0036] Figure 2 is a schematic flow diagram of the energy storage battery thermal management method in this embodiment;

[0037] List of Components and Reference Numerals: 1. Battery box; 1-1. Battery box sandwich; 1-2. Battery box sandwich inlet; 1-3. Battery box sandwich outlet; 2. Battery module; 3. Battery module heat exchange chamber; 3. PTC heating film; 4. Liquid cooling plate; 4-1. Liquid cooling plate flow channel; 4-2. Liquid cooling plate liquid inlet; 4-3. Liquid cooling plate liquid outlet; 5. Phase change material; 6-1, 6-2, 6-3, 6-4, 6-5. Multiple groups of temperature and pressure sensors; 7-1. First electric ball valve; 7-2. Second electric ball valve; 7-3. Third electric ball valve; 7-4. Fourth electric ball valve; 7-5. Fifth electric ball valve; 8. Underground liquid cooling tank; 9. Liquid level gauge; 10. Electric heater; 11. Circulation pump; 12. Liquid filter; 13. Liquid flowmeter; 14. Gas-liquid separator; 15. Environment unit; 16. Centrifugal pump; 17. Gas filter; 18. Gas flowmeter; 19. Control system; a-1. Liquid cooling plate inlet pipeline; a-2. Liquid cooling plate outlet pipeline; b-1. Battery box sandwich inlet pipeline; b-2. Gas-liquid separator outlet pipeline; c-1. Battery box sandwich inlet gas pipeline; c-2. Gas-liquid separator outlet gas pipeline; d. First common end; e. Second common end. Detailed Embodiments

[0038] The present utility model will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0039] The following detailed descriptions are all exemplary descriptions, aiming to provide further detailed explanations for the present utility model. Unless otherwise specified, all technical terms adopted by the present utility model have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. The terms used in the present utility model are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present utility model.

[0040] As Figure 1 shown, the present application provides a thermal management system for energy storage batteries based on shallow underground cold sources in high-altitude and cold regions. The thermal management system for energy storage batteries includes: a battery box 1, a liquid cooling pipeline, an air pipeline, and a control system 19.

[0041] A battery module 2, a PTC (Positive Temperature Coefficient) heating film 3, a liquid cooling plate 4, and a phase change material 5 are installed in the battery box 1; the battery box 1 is a hollow sandwich structure, and an inlet 1-2 and an outlet 1-3 are provided in the battery box sandwich 1-1; the battery module 2 is composed of multiple battery cells symmetrically and evenly distributed along the center of the battery box inside the battery box 1, and the battery cells are connected in series or in parallel; the PTC heating film 3 is closely attached to both sides of the battery cell; the liquid cooling plate 4 is embedded between the single cells of the battery module 2 and absorbs heat through the active flow of coolant liquid; the phase change material 5 is evenly filled in the gaps between the battery cells in the battery box.

[0042] The liquid cooling pipeline includes a first electric ball valve 7-1, an underground liquid cooling tank 8, an electric heater 10, a circulation pump 11, a liquid filter 12, a liquid flowmeter 13, a second electric ball valve 7-2, a third electric ball valve 7-3, and a gas-liquid separator 14; one end of the first electric ball valve 7-1 is connected to the liquid cooling plate liquid outlet 4-3 via the liquid cooling plate liquid outlet pipeline a-2, and the other end is connected to the liquid cooling pipeline in the underground liquid cooling tank 8. One end of the circulation pump 11 is connected to the liquid cooling pipeline arranged in the underground liquid cooling tank 8. When the circulation pump 11 starts, it can forcibly extract the coolant in the underground cooling tank 8 and flow into the liquid cooling plate liquid inlet pipeline a-1 and the battery box sandwich liquid inlet pipeline b-1 through the second electric ball valve 7-2 and the third electric ball valve 7-3 respectively via the liquid filter 12 and the liquid flowmeter 13; the coolant flows into the flow channel in the liquid cooling plate 4 through the liquid cooling plate liquid inlet 4-2 via the liquid cooling plate liquid inlet pipeline a-1, absorbs the heat generated by the battery for heat exchange, then enters the liquid cooling plate liquid outlet pipeline a-2 through the liquid cooling plate liquid outlet 4-3, and returns to the liquid cooling pipeline; the coolant enters the battery box sandwich 1-1 through the battery box sandwich liquid inlet pipeline b-1 and flows into the battery box sandwich 1-1 through the battery box sandwich inlet 1-2, and flows out from the battery box sandwich outlet 1-3. The coolant liquid flows into the gas-liquid separator outlet pipeline b-2 through the gas-liquid separator 14 and returns to the liquid cooling pipeline through the first common end e; the electric heater 10 is arranged on the pipeline between the underground liquid cooling tank 8 and the circulation pump 11, and can supply power to heat the coolant in the pipeline through an external power supply, and heat the energy storage battery through the liquid cooling plate, providing heat for the low-temperature preheating of the energy storage battery.

[0043] A centrifugal pump 16, a gas filter 17, a gas flowmeter 18, a fourth electric ball valve 7-4, a fifth electric ball valve 7-5, and a gas-liquid separator 14 are arranged on the air pipeline; one end of the centrifugal pump 16 is connected to the environmental unit 15, and the other end is connected to the fourth electric ball valve 7-4 via the gas filter 17 and the gas flowmeter 18. The other end of the fourth electric ball valve 7-4 is connected to the battery box sandwich air inlet pipeline c-1; the centrifugal pump 16 sucks in low-density low-temperature air from the environmental unit 15. After filtering the impurities in the air pipeline through the gas filter 17 and measuring the gas flow through the gas flowmeter 18, it flows into the battery box sandwich air inlet pipeline c-1 through the fourth electric ball valve 7-4, enters the battery box sandwich 1-1 through the second common end d and the battery box sandwich inlet 1-2, and forms a large thermal resistance in the battery box sandwich 1-1 by virtue of the low thermal conductivity of the air, effectively blocking the heat transfer in the battery box to the surrounding environment. After the air flows out from the battery box outlet 1-3, it enters the gas-liquid separator 14 through the fifth electric ball valve, and then returns to the environmental unit 15 through the gas-liquid separator outlet pipeline c-2 after the air is separated.

[0044] The control system includes a data acquisition unit, an information processing unit, and a regulating component. The data acquisition unit includes multiple groups of temperature and pressure sensors (6-1, 6-2, 6-3, 6-4, 6-5) arranged on the liquid cooling pipeline and the air pipeline; the parameters of each sensor are connected to the acquisition device which is connected to the control system; the control system obtains and processes the data through the information processing unit and conveys a regulating signal to the regulating component.

[0045] The detailed working principle of this utility model is described as follows:

[0046] The system mainly consists of four major parts: a battery box, a liquid cooling pipeline, an air pipeline, and a control system. The battery box integrates a battery module, a PTC heating film, a liquid cooling plate, and a phase change material, which are used to directly manage the temperature of the battery. The liquid cooling pipeline and the air pipeline respectively regulate the temperature of the battery box through the flow of coolant and air.

[0047] Coolant circulation: The coolant in the underground liquid cooling tank (usually a low-temperature liquid, such as groundwater or a special coolant) is driven by a circulation pump, passes through a liquid filter to remove impurities, and after the flow rate is measured by a liquid flowmeter, it is divided into two paths and enters the battery box. One path enters the liquid cooling plate, absorbs the heat generated by the battery module, and then returns to the liquid cooling pipeline; the other path directly flows into the interlayer of the battery box to further cool the battery box.

[0048] Heating function: In a low-temperature environment, an electric heater heats the coolant in the pipeline, provides preheating for the battery module through the liquid cooling plate, and ensures that the battery reaches an appropriate operating temperature before startup.

[0049] Heat exchange: The coolant in the liquid cooling plate absorbs the heat generated by the battery module through flow, realizing heat exchange and effectively reducing the battery temperature. At the same time, the coolant in the interlayer of the battery box also plays a role in heat insulation and further cooling.

[0050] Air circulation: A centrifugal pump sucks in low-density low-temperature air from the environmental unit, and after passing through a gas filter and a gas flowmeter, it enters the interlayer of the battery box. The air forms a large thermal resistance in the interlayer, effectively blocking the transfer of heat from the inside of the battery box to the outside.

[0051] Thermal insulation: The low thermal conductivity of air forms a good thermal insulation layer in the interlayer of the battery box, reducing the heat exchange between the battery box and the external environment and improving the heat preservation performance of the system.

[0052] Air recovery: The air flowing out of the battery box outlet is processed by a gas-liquid separator and then returned to the environmental unit, realizing the recycling of air.

[0053] Data acquisition: Multiple groups of temperature and pressure sensors arranged on the liquid cooling pipeline and the air pipeline collect the temperature and pressure data of the system in real time.

[0054] Information processing: The control system receives and processes these data through an information processing unit, and judges the current working state of the battery according to preset algorithms and thresholds.

[0055] Adjustment control: According to the processing results, the control system sends adjustment signals to adjustment components (such as electric ball valves, circulation pumps, electric heaters, etc.), automatically adjusting parameters such as the flow rate of the coolant, temperature, and the flow rate of air to ensure that the battery always operates within the optimal working temperature range.

[0056] The utility model provides an efficient and reliable thermal management system for energy storage batteries. This system can effectively manage the temperature of energy storage batteries in high-altitude and cold regions, improving the working efficiency and safety of the batteries.

[0057] In this embodiment, a number of thermocouples are arranged inside the battery box 1 and on the surface of battery cells, measuring the temperature in real time and transmitting it to the control system 19.

[0058] In this embodiment, the PTC heating film 3 is powered by an external power supply, and an adjustable transformer is used to adjust the output voltage of the external power supply, thereby controlling the heating power of the PTC heating film 3.

[0059] In this embodiment, the phase change material 5 is a flexible composite phase change material to reduce the contact thermal resistance between the phase change material and the battery. The flexible composite phase change material is an existing material. The utility model gives a specific solution, and its composition includes paraffin, styrene-ethylene-propylene-styrene, and expanded graphite. Of course, it is not limited to this solution, and other phase change materials can also be used; the phase change material 5 can prevent the battery module 2 from overheating due to excessive heating power of the PTC heating film 3 during low-temperature preheating, and absorb the heat of the battery pack in the form of sensible heat and latent heat during the battery heat dissipation process.

[0060] In this embodiment, the liquid cooling plate 4 dissipates heat from the battery cells it contacts, and each liquid cooling plate 4 has an inlet 4-2 and an outlet 4-3; the flow channel 4-1 structure of the liquid cooling plate is a direct-current circular groove channel.

[0061] In this embodiment, the surface of the PTC heating film 3 is coated with an insulating material to prevent leakage and short-circuit accidents caused by the melting of the phase change material 5; the insulating coating material includes: silicone, epoxy resin, or polyurethane / silica.

[0062] In this embodiment, the underground liquid cooling tank 8 is arranged at a depth of 2 to 5 meters in the shallow underground. The coolant liquid in the pipe exchanges heat with the cold source of the shallow underground soil to keep the coolant liquid in the pipe at a stable low temperature; a liquid level gauge 9 is provided in the underground liquid cooling tank 8 to obtain the coolant liquid level data in the liquid cooling tank in real time, facilitating the replenishment of coolant when the coolant in the liquid cooling tank is insufficient.

[0063] In this embodiment, the electric heater 10 and the PTC heating film 3 are powered by different external power supplies, and different adjustable transformers are used to adjust the output voltage of the external power supply, so as to prevent the two heating devices from losing their heating capabilities simultaneously, which may cause the energy storage battery to be unable to perform low-temperature preheating.

[0064] In this embodiment, a layer of heat-insulating material is coated on the surface of the liquid cooling pipeline to reduce the heat exchange between the coolant cooled by the underground liquid cooling tank 8 and the soil with a relatively high surface temperature, as well as the heat dissipation of the coolant in the liquid cooling pipeline heated by the electric heater to the external environment; the thickness of the heat-insulating cotton is 10 - 40 mm. Specifically, the pipeline with a large heat exchange with the environment is wrapped with 40 mm of heat-insulating cotton, and the pipeline with a small heat exchange with the environment is wrapped with 10 mm of heat-insulating cotton.

[0065] In this embodiment, the coolant in the underground liquid cooling tank and the liquid cooling pipeline includes a mixed solution of water and ethylene glycol. Increasing the concentration of ethylene glycol can effectively lower the freezing point of the coolant, which can reach as low as -48°C at the lowest, so that the coolant in the liquid cooling pipeline is not easy to freeze in a severe cold environment.

[0066] It should be noted that in this embodiment, when the energy storage battery is preheated in a low-temperature environment, air with a low thermal conductivity flows through the battery box interlayer 1 - 1, forming a large thermal resistance at the battery box interlayer 1 - 1. Moreover, as the altitude increases, the air density and thermal conductivity further decrease, and the thermal resistance formed by the air in the battery box interlayer 1 - 1 becomes larger, which can provide an effective heat insulation effect to prevent the heat of the battery from being transferred to the surrounding environment during the low-temperature preheating process. Correspondingly, when the energy storage battery generates a large amount of heat during operation and needs to dissipate heat, when a coolant fluid with a high thermal conductivity flows through the battery box interlayer 1 - 1, the thermal resistance of the battery box can be reduced, canceling the heat insulation effect, which is beneficial to the heat transfer from the battery box 1 to the environment. At the same time, the coolant liquid in the battery box interlayer 1 - 1 can also absorb part of the heat in the battery box 1 and actively take the heat away from the battery box 1.

[0067] This application also provides an energy storage battery thermal management method, which is applied to the energy storage battery thermal management system as described above. As Figure 2 shown, the energy storage battery thermal management method includes:

[0068] The control system collects the temperature data of the energy storage battery, the battery box, the liquid cooling pipeline and the external environment, and judges whether the energy storage battery needs low-temperature preheating or heat dissipation cooling;

[0069] When the energy storage battery has a low-temperature preheating requirement, the control system collects the temperature data of the energy storage battery and calculates and judges the heating requirement. When the preheating requirement of the energy storage battery is large, the first heating mode is selected, that is, the electric heater on the liquid cooling pipeline and the PTC heating film in the battery box work simultaneously to achieve rapid heating. At the same time, the air pipeline transports air with low thermal conductivity into the battery box interlayer to achieve heat insulation and ensure that the battery returns to the working state as soon as possible; if the energy storage battery demand is small, the second heating mode is selected, that is, the electric heater on the liquid cooling pipeline stops working and the PTC heating film in the battery box works. At the same time, the battery box interlayer is filled with air to achieve heat insulation and slow down the heating rate of the energy storage battery to prevent the energy storage battery from overheating.

[0070] When the energy storage battery is in a normal working state, the control system monitors the temperature data on the battery surface and calculates and judges the heat dissipation requirement. When the energy storage battery has a heat dissipation requirement, the cooling mode is selected and the battery box heat preservation function is turned off. At the same time, the degree of heat dissipation requirement is judged. When the heat dissipation requirement is large, the first cooling mode is selected, that is, the coolant in the liquid cooling pipeline starts to flow and circulate for heat dissipation, and the coolant liquid flows into the liquid cooling plate and the battery box interlayer to cool the energy storage battery efficiently; when the heat dissipation requirement is small, the second cooling mode is selected, that is, only the coolant liquid circulating in the liquid cooling plate dissipates heat from the energy storage battery.

[0071] If the control system evaluates that the energy storage system has neither heating nor heat dissipation requirements, it returns to the control system to continue collecting system data;

[0072] After the energy storage adopts the corresponding heating / cooling mode, the control system evaluates whether it meets the energy storage system requirements. If so, the process ends; if not, it returns to the control system to collect system data and re-judge the energy storage system requirements.

[0073] The first heating mode is that the electric heater 10 on the liquid cooling pipeline and the PTC heating film 3 in the battery box 1 jointly heat the battery module 2. The second heating mode is that only the PTC heating film 3 heats the battery module 2. And in both heating modes, the air pipeline works to introduce air into the battery box interlayer 1-1;

[0074] The first cooling mode is that the coolant in the liquid cooling pipeline flows into the liquid cooling plate 4 and the battery box interlayer 1-1 at the same time to dissipate heat from the battery module 2. The second cooling mode is that the coolant in the liquid cooling pipeline only dissipates heat from the battery module 2 through the liquid cooling plate 4.

[0075] The above is only the preferred embodiment of the present utility model and is not intended to limit the present utility model. For those skilled in the art, the present utility model may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art without creative efforts within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A thermal management system for energy storage batteries based on shallow underground cold sources in high-altitude cold regions, characterized in that, Including: A battery box (1), a liquid cooling pipeline, an air pipeline, and a control system (19); A battery module (2), a PTC heating film (3), a liquid cooling plate (4), and a phase change material (5) are installed in the battery box (1); the battery box (1) is a battery box sandwich layer (1-1) with a hollow sandwich structure, and the battery box sandwich layer (1-1) is provided with a battery box sandwich layer inlet (1-2) and a battery box sandwich layer outlet (1-3); the battery module (2) has a plurality of battery cells, and the plurality of battery cells are symmetrically distributed around the center of the battery box and evenly distributed inside the battery box (1), and the battery cells are connected in series or in parallel; the PTC heating film (3) is closely attached to both sides of the battery cell; the liquid cooling plate (4) is embedded between the single cells of the battery module (2); the phase change material (5) is evenly filled in the gaps between the battery cells in the battery box; The liquid cooling pipeline and the air pipeline are respectively connected to the battery box sandwich layer inlet (1-2) through a battery box sandwich layer liquid inlet pipeline (b-1) and a battery box sandwich layer air inlet pipeline (c-1), and the battery box sandwich layer outlet (1-3) is respectively connected to the liquid cooling pipeline and the air pipeline through a liquid-gas separator outlet liquid pipeline (b-2) and a liquid-gas separator outlet air pipeline (c-2) via a liquid-gas separator (14); The control system (19) controls the liquid cooling pipeline and the air pipeline.

2. The energy storage battery thermal management system based on the shallow underground cold source in high-altitude cold regions according to claim 1, characterized in that: A first electric ball valve (7-1), an underground liquid cooling tank (8), a circulation pump (11), a liquid filter (12), and a liquid flow meter (13) are arranged on the liquid cooling pipeline; One end of the first electric ball valve (7-1) is connected to the liquid cooling plate liquid outlet (4-3) through a liquid cooling plate outlet liquid pipeline (a-2), and the other end is connected to the liquid cooling pipeline in the underground liquid cooling tank (8). One end of the circulation pump (11) is connected to the liquid cooling pipeline arranged in the underground liquid cooling tank (8), and the other end is connected to the liquid cooling plate inlet pipeline (a-1) and the battery box sandwich layer liquid inlet pipeline (b-1) through a second electric ball valve (7-2) and a third electric ball valve (7-3) via a liquid filter (12) and a liquid flow meter (13) respectively.

3. The energy storage battery thermal management system based on the shallow underground cold source in high-altitude cold regions according to claim 2, wherein: The underground liquid cooling tank (8) is arranged at a depth of 2 to 5 meters underground, and a liquid level gauge (9) is arranged in the underground liquid cooling tank (8) to obtain the coolant liquid level data in the liquid cooling tank in real time.

4. The energy storage battery thermal management system based on the shallow underground cold source in high altitude and severe cold regions according to claim 2, wherein: An electric heater (10) is also arranged at the inlet of the circulation pump (11).

5. The energy storage battery thermal management system based on the shallow underground cold source in high altitude and severe cold regions according to claim 1, characterized in that: A liquid-gas separator (14), an environmental unit (15), a centrifugal pump (16), a gas filter (17), a gas flow meter (18), and a fourth electric ball valve (7-4) are arranged on the air pipeline; the fourth electric ball valve (7-4) is connected to the battery box sandwich layer inlet (1-2) through a battery box sandwich layer air inlet pipeline (c-1); One end of the centrifugal pump (16) is connected to the environmental unit (15), and the other end is connected to the fourth electric ball valve (7-4) via a gas filter (17) and a gas flow meter (18). The other end of the fourth electric ball valve (7-4) is connected to the battery box sandwich layer air inlet pipeline (c-1).

6. The energy storage battery thermal management system based on the shallow underground cold source in high-altitude and cold regions according to claim 1, wherein: The control system (19) includes a data acquisition unit, an information processing unit, and a regulating component; the data acquisition unit includes multiple groups of temperature and pressure sensors arranged on the liquid cooling pipeline and the air pipeline.

7. The energy storage battery thermal management system based on the shallow underground cold source in high altitude and severe cold regions according to claim 1, wherein: The surface of the PTC heating film (3) is coated with an insulating material.

8. The energy storage battery thermal management system based on the shallow underground cold source in high-altitude cold regions according to claim 1, wherein: The surface of the liquid cooling pipeline is coated with a layer of heat insulation material, and the heat insulation material is heat insulation cotton, and the thickness of the heat insulation cotton is 10 - 40 mm.

9. The energy storage battery thermal management system based on the shallow underground cold source in high-altitude cold regions according to claim 2, wherein: The coolant in the underground liquid cooling tank (8) and the liquid cooling pipeline includes: a mixed solution of water and ethylene glycol.

10. A thermal management system for energy storage batteries based on shallow underground cold sources in high-altitude cold regions according to claim 1, characterized in that: Each liquid cooling plate (4) has a liquid inlet (4-2) and a liquid outlet (4-3); the flow channel (4-1) structure of the liquid cooling plate (4) is a direct current circular groove channel.

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