Immersion energy storage thermal management system and method

Abstract

The invention relates to an immersion energy storage thermal management system, which is used for carrying out thermal management on a battery pack and comprises a refrigerating unit, a first water pump, a pressure sensor and a temperature sensor. The refrigerating unit comprises a compressor. And the immersion liquid for immersing the battery cell of the battery pack circularly flows between the refrigerating unit and the battery pack. And each battery pack is provided with a pressure sensor and a temperature sensor which are used for monitoring the pressure in the battery pack and the temperature of the battery cell. And a pressure threshold value is set in the pressure sensor. The pressure sensor and the temperature sensor are in communication connection with the first water pump. The pressure sensor can adjust the power of the refrigerating unit and the rotating speed of the first water pump according to the pressure in the battery pack, a pressure threshold value and the temperature monitored by the temperature sensor. The pressure in the system can be effectively controlled, and special materials and measures for increasing the thickness of the materials are not needed to improve the pressure bearing capacity of the battery pack body. And when the immersion liquid flows, the explosion-proof valve is prevented from being opened, so that the immersion liquid is prevented from leaking.

Description

Technical Field

[0001] This invention relates to the technical field of immersion energy storage thermal management, and in particular to an immersion energy storage thermal management system and method. Background Technology

[0002] Currently, there are two main methods for thermal management of immersion energy storage. The first is static immersion, where the immersion liquid directly submerges the battery and does not flow. Heat exchange is achieved through internal coils or bottom liquid cooling plates, or no heat exchange is performed on the immersion liquid. The second is dynamic immersion, where the immersion liquid flows and exchanges heat inside the battery pack. Internal flow channels need to be designed to ensure temperature differences.

[0003] The first method offers no advantage over bottom liquid cooling; it increases weight and significantly increases the risk of leakage. The second heat exchange method is less commonly used primarily because the immersion liquid exiting the chiller unit has a high pressure, which puts significant stress on the battery pack. This necessitates a high-strength design for the battery pack, requiring specialized materials and resulting in a substantial increase in weight. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an immersion energy storage thermal management system.

[0005] The immersion energy storage thermal management system provided by this invention adopts the following technical solution:

[0006] An immersion energy storage thermal management system for thermal management of a battery pack 6 includes: a chiller unit 1, a first water pump 3, a pressure sensor, and a temperature sensor. The chiller unit 1 includes a compressor 2. Immersion fluid for the battery pack cells is output from the chiller unit 1 under the drive of the first water pump 3, flows through a first output pipe 101 into the battery pack 6 to exchange heat with the cells, and then flows back to the chiller unit through a first return pipe 102 to form a circulation. Each battery pack is equipped with the pressure sensor and the temperature sensor to monitor the pressure within the battery pack 6 and the temperature of the cells. The pressure sensor has a pressure threshold. Both the pressure sensor and the temperature sensor are communicatively connected to the first water pump 3. The pressure sensor can adjust the power of the chiller unit 1 and the rotation speed of the first water pump 3 based on the pressure within the battery pack 6, the pressure threshold, and the temperature monitored by the temperature sensor.

[0007] Optionally, each battery pack is equipped with an explosion-proof valve; the explosion-proof valve is used to open when the pressure inside the battery pack is greater than its opening pressure to release pressure from the battery pack; the pressure threshold is less than the opening pressure of the explosion-proof valve.

[0008] Optionally, the pressure threshold is 90-95% of the opening pressure of the explosion-proof valve.

[0009] Optionally, the submerged energy storage thermal management system is also used for thermal management of the PCS; the coolant of the PCS circulates through the circulation pipeline under the drive of the second water pump; the submerged energy storage thermal management system also includes a coated heat exchanger; the coated heat exchanger is installed on the refrigeration unit and exchanges heat with the refrigeration unit; the inlet and outlet of the coated heat exchanger are both connected to the circulation pipeline.

[0010] Optionally, it also includes a plate heat exchanger; a fourth shut-off valve is provided on the first output pipeline; the immersion liquid of the submerged battery can also flow back to the compressor through a second return pipeline after exchanging heat with the battery pack, and a first shut-off valve is provided on the second return pipeline; the circulation pipeline includes a main circulation pipeline and a bypass circulation pipeline; a third shut-off valve is provided on the main circulation pipeline; both ends of the bypass circulation pipeline are connected to the main circulation pipeline, and one end is connected to the upstream of the third shut-off valve, and the other end is connected to the downstream of the third shut-off valve; a second shut-off valve is provided on the bypass circulation pipeline; both the bypass circulation pipeline and the second return pipeline pass through the plate heat exchanger and can exchange heat in the plate heat exchanger.

[0011] Optionally, an air-cooled radiator is also included; the air-cooled radiator is installed on the main circulation pipe and is used to reduce the temperature of the coolant in the circulation pipe and control the temperature of the PCS when the temperature of the PCS cannot be controlled by natural heat dissipation alone.

[0012] Optionally, the coated heat exchanger is connected to the circulation pipeline through an inlet pipe and an outlet pipe to form a circulation; a fifth shut-off valve is provided on the inlet pipe; a sixth shut-off valve is provided on the circulation pipeline; the sixth shut-off valve is located between the connection between the inlet pipe and the circulation pipeline and the connection between the outlet pipe and the circulation pipeline; when the fifth shut-off valve is closed and the sixth shut-off valve is open, the coated heat exchanger is disconnected from the PCS.

[0013] Based on the above concept, the present invention also provides a method for immersion energy storage thermal management, wherein thermal management is performed through the aforementioned immersion energy storage thermal management system; the method includes:

[0014] Cooling the battery pack 6: During normal charging and discharging, the immersion liquid submerged in the battery flows from the compressor 2 through the first output pipe 101 to the battery pack 6 to exchange heat with the battery cells, driven by the first water pump 3. Then, it flows back to the compressor 2 through the first return pipe 102 to exchange heat with the compressor 2. A pressure threshold is preset in the pressure sensor. When the temperature of the battery pack 6 exceeds 35°C, the speed of the compressor 2 is adjusted to 90% of its rated speed, and the first water pump 3 is adjusted to its rated speed. Simultaneously, the pressure signal inside the battery pack 6 is monitored. When the pressure signal exceeds the first threshold, the speed of the first water pump 3 is adjusted to 90% of its rated speed. The pressure inside the battery pack 6 is monitored to see if it is lower than the first threshold. If it is higher than the first threshold, the speed of the first water pump 3 is further reduced. If the temperature of the battery pack 6 continues to rise, the compressor 2 is adjusted to its rated speed.

[0015] If the cell temperature is in the medium temperature range, the speed of the compressor 2 continues to decrease to 80% of the rated speed, and at the same time, the speed of the first water pump 3 continues to decrease to 80% of the rated speed, and observe whether the cell temperature is controlled within the range; the upper limit of the medium temperature range is less than 35°C;

[0016] If the cell temperature is in the low temperature range, the speed of the compressor 2 is reduced to 60% of the rated speed; the speed of the first water pump 3 continues to decrease by 10%; if the cell temperature is controlled below 25°C, the compressor 2 is turned off; the first water pump 3 operates at the current speed for autonomous circulation until the temperature difference between the cells drops to within 2°C and then is turned off; the upper limit of the low temperature range is lower than the lower limit of the medium temperature range.

[0017] Optionally, each battery pack is equipped with an explosion-proof valve; the explosion-proof valve is used to open when the pressure inside the battery pack is greater than its opening pressure to release pressure from the battery pack; the pressure threshold is less than the opening pressure of the explosion-proof valve.

[0018] The method also includes:

[0019] PCS cooling: During normal operation, the PCS dissipates heat naturally.

[0020] Battery pack thermal runaway handling: When the battery pack experiences thermal runaway, the compressor operates at full power; the first water pump operates at full power; the explosion-proof valve opens; and the pressure sensor signal is cut off, so that the immersion liquid can circulate at full power and high flow rate to cool the battery cells.

[0021] Optionally, the coolant of the PCS circulates through a circulation pipeline driven by a second water pump; the submerged energy storage thermal management system further includes a cladding heat exchanger and a plate heat exchanger; the cladding heat exchanger is installed on the refrigeration unit and exchanges heat with the refrigeration unit; the inlet and outlet of the cladding heat exchanger are both connected to the circulation pipeline; the circulation pipeline includes a main circulation pipeline and a bypass circulation pipeline; the bypass circulation pipeline and the second return pipeline both pass through the plate heat exchanger and can exchange heat within the plate heat exchanger;

[0022] The method further includes:

[0023] Battery pack heating: The coolant used to cool the PCS can flow through the plate heat exchanger via a bypass circulation pipeline; the immersion liquid for immersing the battery can flow through the plate heat exchanger via a second return pipeline, thereby exchanging heat with the coolant and increasing the temperature of the immersion liquid; at the same time, the inlet and outlet of the coated heat exchanger are both connected to the circulation pipeline, so that the coolant, after flowing through the coated heat exchanger, heats the compressor, thereby increasing the temperature of the immersion liquid.

[0024] Optionally, the PCS cooling further includes: the coolant used to cool the PCS exchanges heat with the immersion liquid in the plate heat exchanger, thereby reducing the temperature of the PCS; when the temperature of the PCS cannot be controlled by the plate heat exchanger, the compressor speed is increased to further cool the coolant; when the temperature of the PCS still cannot be controlled by the plate heat exchanger and the compressor, the temperature of the coolant is further reduced by connecting an air-cooled radiator on the circulation pipeline and making the air-cooled radiator actively operate.

[0025] Optionally, the immersion energy storage thermal management system further includes an air-cooled radiator; the air-cooled radiator is installed on the main circulation pipeline;

[0026] The battery pack thermal runaway handling also includes:

[0027] The PCS is shut down; the fan of the air-cooled radiator runs at full power; the second water pump runs at full speed, thereby removing the heat from the immersion liquid through the plate heat exchanger, so as to quickly cool down the battery pack and prevent heat diffusion.

[0028] Optionally, the medium temperature range is 30-35℃; the low temperature range is 25-30℃.

[0029] As described above, the immersion energy storage thermal management system of the present invention has at least the following beneficial effects:

[0030] 1. By setting up explosion-proof valves and pressure sensors, and linking the speed of the first water pump and compressor, the pressure in the system is effectively controlled. There is no need to use special materials or increase the thickness of materials to improve the pressure resistance of the battery pack. At the same time, it can ensure that the explosion-proof valve will not open when the immersion liquid flows during the charging and discharging process of the battery cell, thus preventing the immersion liquid from leaking and spraying.

[0031] 2. The temperature of the battery cells, the temperature difference between the battery cells, the speed of the compressor, and the speed of the first water pump are all linked together. This effectively and accurately controls the temperature of the battery cells and the temperature difference between the battery cells, while also effectively reducing the energy consumption of the system.

[0032] 3. The PCS adopts liquid cooling and combines it with air cooling. By combining natural heat dissipation and forced air cooling, it effectively utilizes the ambient cooling and the cooling of the battery pack to dissipate heat from the PCS, which helps to reduce the system's energy consumption and noise.

[0033] 4. In low-temperature environments, this system can recover and utilize the heat from the PCS side, using the excess heat to heat the battery cells and compressor, thereby improving the system's heating efficiency and reducing energy consumption.

[0034] 5. During thermal runaway, this system can cool the battery pack by changing the speed of the compressor and the first water pump, using the maximum cooling power and the maximum flow rate, and at the same time increasing the heat dissipation of the air-cooled radiator, so as to quickly suppress the system temperature after thermal runaway occurs and effectively prevent the occurrence of heat diffusion. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of an immersion energy storage thermal management system.

[0036] Figure 2 This is another schematic diagram of the immersion energy storage thermal management system.

[0037] Reference numerals: 1. Refrigeration unit; 2. Compressor; 3. First water pump; 4. Second water pump; 5. Encased heat exchanger; 6. Battery pack; 7. Air-cooled radiator; 8. Plate heat exchanger; 9. PCS; 101. First output pipeline; 102. First return pipeline; 103. Second return pipeline; 104. Main circulation pipeline; 105. Bypass circulation pipeline; 106. Inlet pipeline; 107. Outlet pipeline; 201. First shut-off valve; 202. Second shut-off valve; 203. Third shut-off valve; 204. Fourth shut-off valve; 205. Fifth shut-off valve; 206. Sixth shut-off valve. Detailed Implementation

[0038] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0039] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0040] Please refer to Figure 1 The present invention first discloses an immersion energy storage thermal management system for thermal management of battery pack 6, including: a refrigeration unit 1, a first water pump 3, a pressure sensor and a temperature sensor.

[0041] The refrigeration unit 1 is a relatively mature existing technology used for refrigeration, and it includes a compressor 2, an evaporator and a condenser.

[0042] The immersion solution for the battery pack cells, driven by the first water pump 3, is output from the refrigeration unit 1, flows through the first output pipe 101 into the battery pack 6 to exchange heat with the cells, and then flows back to the refrigeration unit through the first return pipe 102, forming a circulating flow. Each battery pack is equipped with a pressure sensor and a temperature sensor to monitor the pressure inside the battery pack 6 and the temperature of the cells. The pressure sensor has a pressure threshold. Both the pressure sensor and the temperature sensor are communicatively connected to the first water pump 3. The pressure sensor can adjust the power of the refrigeration unit 1 and the rotation speed of the first water pump 3 based on the pressure inside the battery pack 6, the pressure threshold, and the temperature monitored by the temperature sensor.

[0043] When the pressure threshold is correlated with the maximum pressure that the battery pack can withstand, the pressure inside the battery pack is kept below or equal to the pressure threshold by controlling the rotation speed of the first water pump 3. Therefore, it is not necessary to use special materials or increase the material thickness in order to improve the pressure resistance of the battery pack.

[0044] Because the operation of the first water pump 3 fluctuates, the safety of the battery pack remains low when the pressure threshold is correlated with the maximum pressure the battery pack can withstand. In a preferred embodiment of the invention, each battery pack is equipped with an explosion-proof valve. The explosion-proof valve is used to open when the pressure inside the battery pack exceeds its opening pressure, thereby depressurizing the battery pack. The pressure threshold is lower than the opening pressure of the explosion-proof valve.

[0045] Driven by the first water pump 3, the immersion solution for the submerged batteries flows from the compressor 2 through the first output pipe 101 into the battery pack 6 to exchange heat with the battery cells, and then flows back to the compressor 2 through the first return pipe 102 to exchange heat with the compressor 2. Each battery pack 6 is equipped with an explosion-proof valve. Each explosion-proof valve is equipped with a pressure sensor to monitor the pressure inside its respective battery pack 6. Each battery pack 6 is also equipped with a temperature sensor to monitor the temperature of the battery cells within its respective battery pack 6.

[0046] In this embodiment, the explosion-proof valve is mounted on the top cover of the corresponding battery pack 6. The temperature sensor is mounted on the aluminum core of the corresponding battery cell. In other embodiments of the present invention, the explosion-proof valve and the temperature sensor can be installed in other suitable locations without affecting their normal operation.

[0047] Both the pressure sensor and the temperature sensor are communicatively connected to the first water pump 3. The pressure sensor can adjust the speed of the compressor 2 and the first water pump 3 based on the pressure within its battery pack 6, the opening pressure of the explosion-proof valve, and the temperature monitored by the temperature sensor. The speed of the first water pump 3 can be adjusted from 10% to 100% of its rated speed in 10% increments. In other words, the speed of the first water pump 3 can be adjusted to 10%, 20%, 30%, ..., 100% of its rated speed.

[0048] Based on the above structure of the immersion energy storage thermal management system, the present invention can achieve the following functions:

[0049] Cooling of battery pack 6: When the fourth shut-off valve 204 is open and the first shut-off valve 201 is closed, the immersion liquid, after being cooled at the compressor 2, flows into the battery pack 6 through the first output pipe 101 to cool the battery cells in the battery pack 6. The temperature of the immersion liquid rises after exchanging heat with the battery cells and flows back to the compressor 2 through the first return pipe 102 to be cooled again. Because the first shut-off valve 201 is closed, the immersion liquid cannot enter the second return pipe 103.

[0050] Specifically, the explosion-proof valve's function is to release pressure promptly when the internal pressure of the battery abnormally increases; therefore, the pressure inside the battery pack 6 should not exceed the opening pressure of the explosion-proof valve. When the speed of the first water pump 3 increases, the flow rate of the immersion liquid inside the battery pack 6 increases, and the pressure also increases accordingly. When the speed of the compressor 2 increases, the cooling power of the refrigeration unit 1 increases. Therefore, when cooling the battery pack 6, the pressure sensor, temperature sensor, compressor 2, and first water pump 3 must work together to ensure that the temperature of the battery pack 6 is reduced without opening the explosion-proof valve.

[0051] In a preferred embodiment of the present invention, the cooling of the battery pack 6 employs the following control strategy: Before cooling the battery pack 6, a pressure threshold is preset in the pressure sensor. When the temperature of the battery pack 6 exceeds 35°C, the speed of the compressor 2 is adjusted to 90% of its rated speed, and the first water pump 3 is adjusted to its rated speed. Simultaneously, the pressure signal inside the battery pack 6 is monitored. When the pressure signal exceeds the first threshold, the speed of the first water pump 3 is adjusted to 90% of its rated speed. The pressure inside the battery pack 6 is monitored to see if it is lower than the first threshold. If it is higher than the first threshold, the speed of the first water pump 3 is further reduced. If the temperature of the battery pack 6 continues to rise, the compressor 2 is adjusted to its rated speed.

[0052] The pressure threshold is 90-95% of the explosion-proof valve's opening pressure, such as 90%, 91%, 92%, 93%, 94%, or 95%. Setting the pressure threshold appropriately allows for greater adjustment space for the first water pump 3 and also prevents the explosion-proof valve from opening incorrectly when the first water pump 3 is running unstablely.

[0053] If the temperature of battery pack 6 is within the medium temperature range, adjust the speed of compressor 2 to 80% of its rated speed, and simultaneously reduce the speed of the first water pump 3 to 80% of its rated speed. Observe whether the temperature of battery pack 6 is controlled. The upper limit of the medium temperature range is less than or equal to 35°C. If the temperature of battery pack 6 is within the low temperature range, reduce the speed of compressor 2 to 60% of its rated speed. Continue to gradually reduce the speed of the first water pump 3 in 10% increments until the temperature of battery pack 6 is controlled. The upper limit of the low temperature range is lower than the lower limit of the medium temperature range. If the temperature of battery pack 6 is below 25°C, turn off compressor 2, and allow the first water pump 3 to run at its current speed until the temperature difference between the cells within battery pack 6 decreases to within 2°C, then turn it off.

[0054] In a preferred embodiment of the present invention, the medium temperature range is 30-35°C (inclusive of 35°C, exclusive of 30°C). The low temperature range is 25-30°C (inclusive of 30°C and 25°C).

[0055] Please refer to Figure 2In another embodiment of the present invention, the submerged energy storage thermal management system is also used for the thermal management of the PCS9 (Power Conversion System).

[0056] The coolant in PCS9 circulates through the circulation pipeline driven by the second water pump 4. A heat exchanger 5 is installed on the compressor 2 to exchange heat with the immersion liquid inside the compressor 2. Both the inlet and outlet of the heat exchanger 5 are connected to the circulation pipeline.

[0057] First, it should be noted that the immersion energy storage thermal management system of the present invention is a dynamic immersion thermal management system. The immersion liquid enters the battery pack 6 and immerses the battery cells inside. The battery pack 6 is thermally managed through the circulation of the immersion liquid.

[0058] For details, please refer to Figure 2 In a preferred embodiment of the present invention, the immersion energy storage thermal management system is arranged as follows: a fourth shut-off valve 204 is provided on the first output pipeline 101. After exchanging heat with the battery pack 6, the immersion liquid of the immersion battery can also flow back to the compressor 2 through the second return pipeline 103, and a first shut-off valve 201 is provided on the second return pipeline 103.

[0059] The circulation pipeline includes a main circulation pipeline 104 and a bypass circulation pipeline 105. A third shut-off valve 203 is installed on the main circulation pipeline 104. Both ends of the bypass circulation pipeline 105 are connected to the main circulation pipeline 104, with one end connected upstream of the third shut-off valve 203 and the other end connected downstream of the third shut-off valve 203. A second shut-off valve 202 is installed on the bypass circulation pipeline 105. A plate heat exchanger 8 is installed on the main circulation pipeline 104. Both the main circulation pipeline 104 and the second return pipeline 103 flow through the plate heat exchanger 8, and the two can exchange heat within the plate heat exchanger 8.

[0060] The heat exchanger 5 is a heat exchanger that encloses the heat exchange pipes on the compressor 2. It is connected to the main circulation pipe 104 through the inlet pipe 106 and the outlet pipe 107 to form a circulation. A fifth shut-off valve 205 is installed on the inlet pipe 106. A sixth shut-off valve 206 is installed on the circulation pipe. The sixth shut-off valve 206 is located between the connection between the inlet pipe 106 and the circulation pipe and the connection between the outlet pipe 107 and the circulation pipe. An air-cooled radiator 7 is also installed on the main circulation pipe 104. The air-cooled radiator 7 blows air into the main circulation pipe 104 through the rotation of a fan, thereby accelerating the heat dissipation of the coolant in the main circulation pipe 104. The speed of the fan of the air-cooled radiator 7 can also be adjusted.

[0061] To more clearly illustrate the flow paths of the immersion fluid and coolant, Figure 2The compressor 2 and the first water pump 3 are displayed outside the refrigeration unit 1, while the second water pump 4 is displayed outside the PCS9. In reality, the compressor 2 and the first water pump 3 are integrated into the refrigeration unit 1, while the second water pump 4 is integrated into the PCS9.

[0062] With the above arrangement, the immersion energy storage thermal management system of the present invention can achieve the following functions:

[0063] 1. Cooling PCS9: During normal operation, PCS9 is cooled by natural heat dissipation, and the air-cooled radiator 7 does not operate actively. At this time, the second shut-off valve 202 and the fifth shut-off valve 205 are closed, while the third shut-off valve 203 and the sixth shut-off valve 206 are open. This prevents the cooling water from circulating through the heat exchanger 5, effectively disconnecting the heat exchanger 5 from PCS9. When the cell temperature is below 35℃ and the PCS9 temperature exceeds the threshold, the third shut-off valve 203 can be closed, and the second shut-off valve 202 opened. This allows the coolant in the main circulation pipe 104 to enter the bypass circulation pipe 105, where it exchanges heat with the relatively cooler immersion liquid in the second return pipe 103 in the plate heat exchanger 8, lowering its temperature and thus cooling PCS9. If the coolant temperature still does not reach the target temperature after passing through the plate heat exchanger 8, the compressor 2 speed needs to be increased. If increasing the speed of compressor 2 still cannot control the temperature of PCS9, start the air-cooled radiator 7 to dissipate heat from the coolant and further reduce the temperature of PCS9.

[0064] 2. Heating the battery pack 6: When the PCS9 is operating normally, the temperature of the coolant entering the PCS9 for heat exchange is around 58℃. To heat the battery pack 6, open the first shut-off valve 201 and the second shut-off valve 202, and close the third shut-off valve 203 and the fourth shut-off valve 204. This allows the immersion liquid to circulate through the second return pipe 103 and exchange heat with the coolant in the bypass circulation pipe 105 in the plate heat exchanger 8, increasing its temperature and thus heating the compressor 2 and the battery cells, effectively improving the heating efficiency of the battery pack 6 in low-temperature environments.

[0065] 3. Control of thermal runaway in battery pack 6: When thermal runaway occurs in battery pack 6, a large amount of immersion fluid needs to be injected into the cells to cool them down. Compressor 2 runs at full power, first water pump 3 runs at full power, explosion-proof valve is opened, and pressure sensor signal is cut off, so that the immersion fluid can circulate at full power and high flow rate to cool the cells. At the same time, PCS9 is shut down, first shut-off valve 201 and second shut-off valve 202 are opened, third shut-off valve 203 and fourth shut-off valve 204 are closed, and the fan of air-cooled radiator 7 runs at full speed. Second water pump 4 runs at full speed, and some of the heat in the immersion fluid is removed through plate heat exchanger 8, so that the entire battery pack 6 is cooled down quickly to prevent heat diffusion.

[0066] Compared with the prior art, the immersion energy storage thermal management system of the present invention has the following advantages:

[0067] 1. By setting up an explosion-proof valve and a pressure sensor, and linking the speed of the first water pump 3 and the compressor 2, the pressure in the system is effectively controlled. There is no need to use special materials or increase the thickness of materials to improve the pressure resistance of the battery pack 6. At the same time, it can ensure that the explosion-proof valve will not open when the immersion liquid flows during the charging and discharging process of the battery cells, thus preventing the immersion liquid from leaking and spraying.

[0068] 2. The temperature of the battery cells, the temperature difference between the battery cells, the speed of the compressor 2, and the speed of the first water pump 3 are interconnected, which can effectively and accurately control the temperature of the battery cells and the temperature difference between the battery cells, while effectively reducing the energy consumption of the system.

[0069] 3. The PCS9 uses liquid cooling combined with air cooling radiator 7. By combining natural cooling and forced air cooling, it effectively utilizes the ambient cooling and the cooling on the battery pack side 6 to dissipate heat from the PCS9, which helps to reduce system energy consumption and noise.

[0070] 4. In low-temperature environments, this system can recover and utilize the heat from the PCS9 side, using the excess heat to heat the battery cells and compressor 2, thereby improving the system's heating efficiency and reducing energy consumption.

[0071] 5. During thermal runaway, this system can cool the battery pack 6 by changing the speed of compressor 2 and the first water pump 3, using the maximum cooling power and the maximum flow rate, and at the same time increase the heat dissipation of the air-cooled radiator 7, so as to quickly suppress the system temperature after thermal runaway occurs and effectively prevent the occurrence of heat diffusion.

[0072] This invention also discloses a method for thermal management of submerged energy storage, wherein thermal management is performed through the aforementioned submerged energy storage thermal management system. The method includes:

[0073] Cooling Battery Pack 6: Before cooling battery pack 6, a pressure threshold is preset in the pressure sensor. When the temperature of battery pack 6 exceeds 35℃, the speed of compressor 2 is adjusted to 90% of its rated speed, and the first water pump 3 is adjusted to its rated speed. Simultaneously, the pressure signal inside battery pack 6 is monitored. When the pressure signal exceeds the first threshold, the speed of the first water pump 3 is adjusted to 90% of its rated speed, and the pressure inside battery pack 6 is monitored to see if it is below the first threshold. If it is above the first threshold, the speed of the first water pump 3 is further reduced. If the temperature of battery pack 6 continues to rise, compressor 2 is adjusted to its rated speed. The pressure threshold is 90-95% of the explosion-proof valve opening pressure.

[0074] If the temperature of battery pack 6 is between 30-35℃, adjust the speed of compressor 2 to 80% of its rated speed, and simultaneously reduce the speed of the first water pump 3 to 80% of its rated speed, observing whether the temperature of battery pack 6 is controlled. If the temperature of battery pack 6 is between 25-30℃, reduce the speed of compressor 2 to 60% of its rated speed. Continue to gradually reduce the speed of the first water pump 3 in 10% increments until the temperature of battery pack 6 is controlled. If the temperature of battery pack 6 is below 25℃, turn off compressor 2, and allow the first water pump 3 to run at its current speed until the temperature difference between the battery cells in battery pack 6 decreases to within 2℃, then turn it off.

[0075] PCS9 Cooling: During normal operation, PCS9 dissipates heat naturally. The coolant used to cool PCS9 exchanges heat with the immersion liquid in the plate heat exchanger 8, lowering its temperature and thus reducing the temperature of PCS9. When the temperature of PCS9 cannot be controlled by the plate heat exchanger 8, the speed of compressor 2 is increased to further cool the coolant. When the temperature of PCS9 still cannot be controlled by the plate heat exchanger 8 and compressor 2, the temperature of the coolant is further reduced by connecting an air-cooled radiator 7 to the circulation pipeline and actively operating the air-cooled radiator 7.

[0076] The cooling of PCS9 specifically includes the following steps: During normal operation, PCS9 can be cooled by natural heat dissipation, and the air-cooled radiator 7 does not operate actively. At this time, the second shut-off valve 202 and the fifth shut-off valve 205 are closed, while the third shut-off valve 203 and the sixth shut-off valve 206 are open. This prevents the cooling water from circulating through the encased heat exchanger 5, effectively disconnecting the encased heat exchanger 5 from the PCS9. When the cell temperature is controlled below 35°C and the temperature of PCS9 exceeds the threshold, the third shut-off valve 203 can be closed, and the second shut-off valve 202 can be opened. This allows the coolant in the main circulation pipe 104 to enter the bypass circulation pipe 105, where it exchanges heat with the relatively cooler immersion liquid in the second return pipe 103 in the plate heat exchanger 8, thus lowering the temperature and cooling the PCS9. If the coolant temperature still does not reach the target temperature after passing through the plate heat exchanger 8, the speed of the compressor 2 needs to be increased. If increasing the speed of the compressor 2 still cannot control the temperature of PCS9, the air-cooled radiator 7 is activated to dissipate heat from the coolant, further reducing the temperature of PCS9.

[0077] Battery pack 6 heating: The coolant used to cool PCS9 can flow through the plate heat exchanger 8 via the bypass circulation line 105. The immersion fluid for submerging the battery can flow through the plate heat exchanger 8 via the second return line 103, thereby exchanging heat with the coolant and increasing the temperature of the immersion fluid. At the same time, the inlet and outlet of the heat exchanger are both connected to the circulation line, so that the coolant, after flowing through the heat exchanger, heats the compressor 2, thereby increasing the temperature of the immersion fluid.

[0078] The heating of battery pack 6 specifically includes: When PCS9 is working normally, the temperature of the coolant entering PCS9 and exchanging heat with PCS9 is about 58°C. If it is necessary to heat battery pack 6, the first shut-off valve 201 and the second shut-off valve 202 are opened, and the third shut-off valve 203 and the fourth shut-off valve 204 are closed, so that the immersion liquid circulates through the second return pipe 103 and exchanges heat with the coolant in the bypass circulation pipe 105 in the plate heat exchanger 8, thereby increasing the temperature and heating the compressor 2 and the battery cells.

[0079] Thermal runaway handling of battery pack 6: When thermal runaway occurs in battery pack 6, compressor 2 runs at full power, first water pump 3 runs at full power, explosion-proof valve opens, and pressure sensor signal is cut off, so that the immersion liquid can circulate at full power and high flow rate to cool the battery cells.

[0080] The thermal runaway handling of battery pack 6 specifically includes: When thermal runaway occurs in battery pack 6, a large amount of immersion fluid needs to be injected into the battery cells to cool them down. Compressor 2 operates at full power, the first water pump 3 operates at full power, the explosion-proof valve is opened, and the pressure sensor signal is cut off, so that the immersion fluid can circulate at full power and high flow rate to cool the battery cells. At the same time, PCS9 is shut down, the first shut-off valve 201 and the second shut-off valve 202 are opened, the third shut-off valve 203 and the fourth shut-off valve 204 are closed, and the fan of the air-cooled radiator 7 and the second water pump 4 operate at full speed. Through the plate heat exchanger 8, some of the heat in the immersion fluid is removed, so that the entire battery pack 6 is cooled down rapidly to prevent heat diffusion.

[0081] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An immersion energy storage thermal management system for thermal management of a battery pack (6), characterized in that, include: The chiller unit (1), the first water pump (3), the pressure sensor, and the temperature sensor; among which, The refrigeration unit (1) includes a compressor (2); the immersion liquid for immersing the battery pack cells is output from the refrigeration unit (1) under the drive of the first water pump (3), flows through the first output pipeline (101) into the battery pack (6) to exchange heat with the cells, and then flows back to the refrigeration unit through the first return pipeline (102) to form a circulating flow; Each battery pack is equipped with the pressure sensor and the temperature sensor to monitor the pressure and temperature of the cells within the battery pack (6); the pressure sensor is equipped with a pressure threshold. Both the pressure sensor and the temperature sensor are communicatively connected to the first water pump (3); the pressure sensor can adjust the power of the refrigeration unit (1) and the speed of the first water pump (3) according to the pressure in the battery pack (6), the pressure threshold and the temperature monitored by the temperature sensor.

2. The immersion energy storage thermal management system according to claim 1, characterized in that: Each battery pack is equipped with an explosion-proof valve; the explosion-proof valve is used to open when the pressure inside the battery pack is greater than its opening pressure, so as to release the pressure of the battery pack. The pressure threshold is less than the opening pressure of the explosion-proof valve.

3. The immersion energy storage thermal management system according to claim 2, characterized in that: The pressure threshold is 90-95% of the opening pressure of the explosion-proof valve.

4. The immersion energy storage thermal management system according to claim 1, characterized in that: The immersion energy storage thermal management system is also used for thermal management of the PCS (9); The coolant of PCS (9) circulates through the circulation pipeline under the drive of the second water pump (4); The immersion energy storage thermal management system also includes a coated heat exchanger (5); the coated heat exchanger (5) is installed on the refrigeration unit (1) and exchanges heat with the refrigeration unit (1); the inlet and outlet of the coated heat exchanger (5) are both connected to the circulation pipeline.

5. The immersion energy storage thermal management system according to claim 4, characterized in that: It also includes plate heat exchangers (8); A fourth shut-off valve (204) is provided on the first output pipeline (101); the immersion liquid of the battery can also flow back to the compressor (2) through the second return pipeline (103) after exchanging heat with the battery pack (6), and a first shut-off valve (201) is provided on the second return pipeline (103); The circulation pipeline includes a main circulation pipeline (104) and a bypass circulation pipeline (105); a third shut-off valve (203) is provided on the main circulation pipeline (104); both ends of the bypass circulation pipeline (105) are connected to the main circulation pipeline (104), and one end is connected to the upstream of the third shut-off valve (203), and the other end is connected to the downstream of the third shut-off valve (203); a second shut-off valve (202) is provided on the bypass circulation pipeline (105). The bypass circulation pipeline (105) and the second return pipeline (103) both pass through the plate heat exchanger (8) and can exchange heat in the plate heat exchanger (8).

6. The immersion energy storage thermal management system according to claim 5, characterized in that, It also includes air-cooled radiators (7); The air-cooled radiator (7) is installed on the main circulation pipe (104) and is used to reduce the temperature of the coolant in the circulation pipe and control the temperature of the PCS (9) when the temperature of the PCS (9) cannot be controlled by natural heat dissipation alone.

7. The immersion energy storage thermal management system according to claim 5, characterized in that, The coated heat exchanger (5) is connected to the circulation pipeline through the inlet pipe (106) and the outlet pipe (107) to form a circulation; A fifth shut-off valve (205) is provided on the water inlet pipe (106); a sixth shut-off valve (206) is provided on the circulation pipe; the sixth shut-off valve (206) is located between the connection between the water inlet pipe (106) and the circulation pipe and the connection between the water outlet pipe (107) and the circulation pipe. When the fifth shut-off valve (205) is closed and the sixth shut-off valve (206) is open, the encapsulated heat exchanger (5) is disengaged from the PCS (9).

8. A method for managing submerged energy storage thermal power, wherein thermal management is performed using the submerged energy storage thermal management system as described in any one of claims 1-7; characterized in that, The method includes: Cooling the battery pack (6): When the battery pack (6) is charging and discharging normally, the immersion liquid that submerges the battery flows from the compressor (2) through the first output pipe (101) to the battery pack (6) to exchange heat with the battery cells under the drive of the first water pump (3), and then flows back to the compressor (2) through the first return pipe (102) to exchange heat with the compressor (2); a pressure threshold is preset in the pressure sensor; when the temperature of the battery pack (6) exceeds 35°C, the speed of the compressor (2) is adjusted to 90% of the rated speed, the first water pump (3) is adjusted to the rated speed, and the pressure signal in the battery pack (6) is monitored at the same time. When the pressure signal exceeds the first threshold, the speed of the first water pump (3) is adjusted to 90% of the rated speed, and the pressure in the battery pack (6) is monitored to see if it is lower than the first threshold. If it is higher than the first threshold, the speed of the first water pump (3) is further reduced; if the temperature of the battery pack (6) continues to rise, the compressor (2) is adjusted to the rated speed. If the cell temperature is in the medium temperature range, the speed of the compressor (2) continues to decrease to 80% of the rated speed, and at the same time the speed of the first water pump (3) continues to decrease to 80% of the rated speed. Observe whether the cell temperature is controlled within the range; the upper limit of the medium temperature range is less than or equal to 35°C. If the cell temperature is in the low temperature range, the speed of the compressor (2) is reduced to 60% of the rated speed; the speed of the first water pump (3) continues to decrease by 10%; if the cell temperature is controlled below 25°C, the compressor (2) is turned off; the first water pump (3) automatically circulates at the current speed until the temperature difference between the cells drops to within 2°C and then turns off; the upper limit of the low temperature range is lower than the lower limit of the medium temperature range.

9. The method according to claim 8, characterized in that, Each battery pack is equipped with an explosion-proof valve; the explosion-proof valve is used to open when the pressure inside the battery pack is greater than its opening pressure to release pressure from the battery pack; the pressure threshold is less than the opening pressure of the explosion-proof valve. The method further includes: PCS(9) Cooling: During normal operation, PCS(9) dissipates heat naturally; Thermal runaway handling of battery pack (6): When thermal runaway occurs in battery pack (6), the compressor (2) operates at full power; the first water pump (3) operates at full power; the explosion-proof valve is opened; the pressure sensor signal is cut off; so that the immersion liquid can circulate at full power and high flow rate to cool the battery cells.

10. The method according to claim 9, characterized in that, The coolant of the PCS (9) circulates through the circulation pipeline under the drive of the second water pump (4); the immersion energy storage thermal management system also includes a cladding heat exchanger (5) and a plate heat exchanger (8); the cladding heat exchanger (5) is installed on the refrigeration unit (1) and exchanges heat with the refrigeration unit (1); the inlet and outlet of the cladding heat exchanger (5) are both connected to the circulation pipeline; the circulation pipeline includes a main circulation pipeline (104) and a bypass circulation pipeline (105); the bypass circulation pipeline (105) and the second return pipeline (103) both pass through the plate heat exchanger (8) and can exchange heat in the plate heat exchanger (8); The method further includes: Battery pack (6) heating: The coolant used to cool the PCS (9) can flow through the plate heat exchanger (8) via the bypass circulation line (105); the immersion liquid of the submerged battery can flow through the plate heat exchanger (8) via the second return line (103) to exchange heat with the coolant and increase the temperature of the immersion liquid. Meanwhile, the inlet and outlet of the coated heat exchanger (5) are both connected to the circulation pipeline, so that the coolant flows through the coated heat exchanger (5) and heats the compressor (2), thereby increasing the temperature of the immersion liquid.

11. The method according to claim 10, characterized in that, The cooling of the PCS (9) also includes: The coolant used to cool the PCS (9) exchanges heat with the immersion liquid in the plate heat exchanger (8), and the temperature decreases, thereby reducing the temperature of the PCS (9). When the temperature of the PCS (9) cannot be controlled by the plate heat exchanger (8), the speed of the compressor (2) is increased to further cool the coolant. When the temperature of the PCS (9) still cannot be controlled by the plate heat exchanger (8) and the compressor (2), the temperature of the coolant is further reduced by connecting an air-cooled radiator (7) to the circulation pipeline and making the air-cooled radiator (7) work actively.

12. The method according to claim 10, characterized in that, The immersion energy storage thermal management system also includes an air-cooled radiator (7); the air-cooled radiator (7) is installed on the main circulation pipeline (104); The thermal runaway handling of the battery pack (6) also includes: PCS (9) is turned off; the fan of the air-cooled radiator (7) is running at full power; the second water pump (4) is running at full speed, and then the heat of the immersion liquid is carried away through the plate heat exchanger (8) so that the battery pack (6) is cooled down quickly and heat diffusion is prevented.

13. The method according to claim 10, characterized in that, The medium temperature range is 30-35℃; the low temperature range is 25-30℃.

Images