An immersion liquid-cooled battery module and a control method thereof

Abstract

The present application relates to the technical field of immersed liquid-cooled battery, and discloses an immersed liquid-cooled battery module and a control method thereof, wherein the immersed liquid-cooled battery module is divided into a first cavity and a second cavity by a partition plate, an electrode column and a pressure relief valve are located in the second cavity, the second cavity is not filled with cooling liquid during normal operation, thereby effectively avoiding insulation failure and short circuit risk caused by long-term immersion of the electrode, when thermal runaway occurs, the independent second cavity is used as an exhaust buffer and an emergency liquid injection channel, and is combined with a pressure relief structure to realize gas-liquid separation and exhaust, prevent system pressure from losing control and medium from flowing out, and actively inject liquid through a second liquid inlet after the pressure relief valve is opened, utilize injection pressure to overcome gas resistance effect, so that the cooling liquid can reach the internal core of the battery monomer along the opened pressure relief valve, and realize pinpoint accurate cooling and thermal diffusion blocking.

Description

Technical Field

[0001] This invention relates to the field of battery module technology, and in particular to an immersion liquid-cooled battery module and its control method. Background Technology

[0002] Energy storage batteries generate enormous amounts of heat when thermal runaway occurs, which can easily trigger a chain reaction. To control battery temperature, existing technologies include immersion liquid cooling solutions. Traditional fully immersion liquid cooling systems dissipate heat by completely submerging the battery in an insulating coolant.

[0003] However, existing fully immersed liquid cooling systems have significant technical drawbacks in practical applications. First, under normal operating conditions, the positive and negative terminals of the battery are completely immersed in the coolant for extended periods, placing extremely high demands on the performance of the insulating fluid. This can easily lead to micro-short circuits or electrochemical corrosion of the electrodes, and also results in high sealing requirements and expensive maintenance. Second, when dealing with thermal runaway pressure relief, the ejected high-temperature gas mixes violently with the surrounding liquid, forming a "gas-liquid two-phase flow." This not only obstructs the exhaust path and causes a rapid increase in system pressure that damages the sealing structure, but also results in a large amount of insulating fluid being discharged with the gas, leaving the remaining batteries without a cooling medium. Finally, the high-pressure gas flow accompanying thermal runaway creates a significant gas resistance effect. The high-speed outward ejection of gas creates a high-pressure zone at the vent valve, blocking the return flow of surrounding stagnant or low-velocity liquid. This prevents the coolant from entering the battery in time for targeted cooling, making it difficult to effectively block heat diffusion at its source. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an immersion liquid-cooled battery module and its control method, which aims to solve the technical problems of insulation risk of electrodes being immersed for a long time during normal operation of existing immersion liquid cooling systems, as well as the inconvenience of depressurization and the difficulty of coolant entering the battery under thermal runaway conditions.

[0005] To address the aforementioned technical problems, the present invention provides an immersion-type liquid-cooled battery module, comprising: The housing is equipped with a first liquid inlet, a first liquid outlet, a second liquid inlet, and a pressure relief structure; A partition plate is installed inside the box, which divides the interior of the box into a first cavity and a second cavity. The first cavity is located below the second cavity. The first cavity is connected to the first liquid inlet and the first liquid outlet, respectively. The second cavity is connected to the second liquid inlet. The pressure relief structure is used to relieve pressure in the second cavity. The partition plate is provided with multiple mounting holes. Multiple battery cells are inserted into the mounting holes one by one. The battery cells are sealed to the mounting holes, so that the first cavity and the second cavity are isolated from each other. The bottom of the battery cell is located in the first cavity, and the top of the battery cell is provided with an electrode post and a relief valve located in the second cavity. The second inlet is configured to inject coolant into the second cavity after the explosion relief valve is opened, and the coolant can enter the interior of the battery cell through the explosion relief valve.

[0006] As a preferred embodiment of the present invention, the pressure relief structure is a first pressure relief valve, which is connected to the second cavity. The first pressure relief valve is used to release air outward when the air pressure in the second cavity exceeds a set value.

[0007] As a preferred embodiment of the present invention, the battery module further includes a protective box, the box body is housed inside the protective box, a third cavity is formed between the outer wall of the box body and the inner wall of the protective box, the gas discharged after the first pressure relief valve is opened can enter the third cavity, the protective box is provided with a second pressure relief valve, the second pressure relief valve is configured to open when the gas pressure in the third cavity rises to a set value, so as to exhaust gas to the outside.

[0008] As a preferred embodiment of the present invention, the second cavity is provided with a detection component, which is used to detect the thermal runaway state of the battery cell and the opening state of the explosion relief valve.

[0009] As a preferred embodiment of the present invention, the housing is further provided with a second liquid outlet communicating with the second cavity, a main liquid inlet pipe is provided at the first liquid inlet, the main liquid inlet pipe is connected to the second liquid inlet through a liquid inlet branch pipe, a first switch valve is provided on the liquid inlet branch pipe, a main liquid outlet pipe is provided at the first liquid outlet, the main liquid outlet pipe is connected to the second liquid outlet through a liquid outlet branch pipe, and a second switch valve is provided on the liquid outlet branch pipe.

[0010] As a preferred embodiment of the present invention, a positioning plate is provided in the first cavity, and the positioning plate is provided with a plurality of positioning grooves corresponding one-to-one with the battery cells, and the positioning grooves cooperate with the bottom of the battery cells.

[0011] The present invention also provides a control method for an immersion liquid-cooled battery module, applicable to the above-mentioned immersion liquid-cooled battery module, comprising: In normal operating mode, the first liquid inlet is opened to allow coolant to enter the first cavity through the first liquid inlet, immerse the bottom of the battery cell for heat exchange, and then discharge through the first liquid outlet. In the thermal runaway handling mode, when thermal runaway of the battery cell is detected and the explosion relief valve is opened, the second liquid inlet is controlled to open, and coolant is injected into the second cavity through the second liquid inlet. The coolant enters the interior of the battery cell through the opened explosion relief valve.

[0012] As a preferred embodiment of the present invention, in the thermal runaway handling mode, when thermal runaway of the battery cell is detected and the explosion relief valve is opened, the gas pressure in the second cavity is first waited for to stabilize before coolant is injected into the second cavity.

[0013] As a preferred embodiment of the present invention, the step of determining that the air pressure in the second cavity tends to be stable is as follows: the air pressure value in the second cavity is collected by a pressure sensor at a preset sampling frequency. When the absolute value of the air pressure difference between two adjacent sampling times is less than the preset stability threshold within a preset determination time, it is determined that the air pressure in the second cavity has tended to be stable, and the liquid injection step is triggered.

[0014] As a preferred embodiment of the present invention, if the waiting time exceeds a preset safe time threshold while waiting for the gas pressure in the second cavity to stabilize, the liquid injection step is forcibly triggered.

[0015] This invention discloses an immersion liquid-cooled battery module and its control method. Compared with the prior art, its advantages are as follows: This invention divides the battery into a first cavity and a second cavity by a partition plate. The electrode posts and the explosion relief valve are located in the second cavity. During normal operation, the second cavity is not injected with coolant, effectively avoiding insulation failure and short circuit risk caused by long-term immersion of the electrodes. In case of thermal runaway, the independent second cavity is used as an exhaust buffer and emergency liquid injection channel. Combined with the pressure relief structure, gas-liquid separation and exhaust are achieved to prevent system pressure runaway and medium loss. Liquid is actively injected through the second liquid inlet after the explosion relief valve is opened. The injection pressure overcomes the gas resistance effect, allowing the coolant to reach the core of the battery through the opened explosion relief valve, achieving precise cooling and thermal diffusion blocking. Attached Figure Description

[0016] Figure 1 This is a structural diagram of an immersion liquid-cooled battery module according to the present invention; Figure 2 yes Figure 1 The fracture structure diagram; Figure 3 This is an exploded structural diagram of the connection between the housing and the battery cell of the present invention; Figure 4 This is a cross-sectional view of the box body of the present invention; In the diagram, 1. Box body; 11. First liquid inlet; 111. Liquid inlet pipe; 112. Liquid inlet branch pipe; 12. First liquid outlet; 121. Liquid outlet pipe; 122. Liquid outlet branch pipe; 13. Second liquid inlet; 131. Second liquid outlet; 14. First pressure relief valve; 15. First cavity; 16. Second cavity; 2. Divider plate; 21. Mounting hole; 3. Battery cell; 31. Electrode post; 32. Explosion relief valve; 4. Protective box; 41. Third cavity; 42. Second pressure relief valve; 5. Positioning plate; 51. Positioning groove. Detailed Implementation

[0017] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used to indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] like Figure 1-4 As shown, a preferred embodiment of the present invention provides an immersion liquid-cooled battery module, comprising: a housing 1, a partition plate 2, and multiple battery cells 3. The housing 1 is provided with a first liquid inlet 11, a first liquid outlet 12, a second liquid inlet 13, and a pressure relief structure. The partition plate 2 is installed inside the housing 1, dividing the interior of the housing 1 into a first cavity 15 and a second cavity 16. The first cavity 15 is located below the second cavity 16 and is connected to both the first liquid inlet 11 and the first liquid outlet 12. The second cavity 16 is connected to the second liquid inlet 13. The pressure relief structure is used to supply the first liquid inlet 11 to the second liquid outlet 12. The second cavity 16 is depressurized, and the partition plate 2 is provided with multiple mounting holes 21. Multiple battery cells 3 are inserted into the mounting holes 21 one by one, and the battery cells 3 are sealed to the mounting holes 21, so that the first cavity 15 and the second cavity 16 are isolated from each other. The bottom of the battery cell 3 is located in the first cavity 15, and the top of the battery cell 3 is provided with an electrode post 31 and a pressure relief valve 32 located in the second cavity 16. The second liquid inlet 13 is configured to inject coolant into the second cavity 16 after the pressure relief valve 32 is opened, and the coolant can enter the interior of the battery cell 3 through the pressure relief valve 32.

[0020] This compartmentalized design achieves a "liquid at the bottom, dry at the top" working environment. The first compartment 15 serves as the regular cooling area, using flowing coolant to remove the heat generated during battery operation. The second compartment 16 serves as the electrical connection area and emergency coolant injection area, remaining dry under normal conditions. This effectively avoids the risk of electrochemical corrosion or short circuits that might occur if the electrode posts 31 are immersed in coolant for extended periods. The pressure relief structure acts as a gas release channel. When the battery experiences thermal runaway, a large amount of gas will accumulate in the second compartment 16 within a short time. The pressure relief structure can open when the pressure increases. This prevents the housing 1 from physically exploding due to excessive internal pressure. Simultaneously, in the event of thermal runaway, the second inlet 13 injects coolant into the second compartment 16. Under the combined action of gravity and injection pressure, the coolant directly flows into the battery through the opened relief valve 32. The coolant directly contacts the high-temperature materials inside the battery, which rapidly reduces the temperature of the core thermal runaway region.

[0021] For example, see Figure 2 The pressure relief structure consists of a first pressure relief valve 14, which is connected to the second cavity 16. The first pressure relief valve 14 releases gas when the pressure inside the second cavity 16 exceeds a set value. As a pressure-sensitive element, the first pressure relief valve 14 has a defined opening threshold. This means that the valve remains closed under slight pressure fluctuations generated during normal battery operation. This ensures the sealing of the second cavity 16, preventing external moisture or dust from flowing back and contaminating the electrode area. Only when the gas pressure generated by thermal runaway exceeds the safety threshold will the first pressure relief valve 14 respond and open rapidly. This achieves intelligent control with "sealed protection under normal conditions and directional venting in emergencies." This controlled venting method is safer than a normally open vent.

[0022] For example, see Figure 1 and 2 This battery module also includes a protective housing 4, with the housing 1 housed within it. A third cavity 41 is formed between the outer wall of the housing 1 and the inner wall of the protective housing 4. Gas discharged after the first pressure relief valve 14 is opened can enter the third cavity 41. The protective housing 4 is equipped with a second pressure relief valve 42, which is configured to open when the gas pressure in the third cavity 41 rises to a set value, thereby venting gas to the outside. The third cavity 41 forms a space for gas buffering and cooling. The high-temperature gas discharged from the first pressure relief valve 14 first enters the third cavity 41 for expansion and cooling. This prevents high-temperature ejected materials from being directly discharged into the external environment. The second pressure relief valve 42 provides two-stage pressure relief protection. This dual-housing structure not only enhances physical protection capabilities but also mitigates the pressure shock caused by thermal runaway through a step-by-step pressure relief method.

[0023] For example, a detection component (not shown in the figure) is provided in the second cavity 16. The detection component is used to detect the thermal runaway state of the battery cell 3 and the opening state of the explosion relief valve 32. The detection component can be a temperature sensor, a pressure sensor, or a gas composition sensor. The detection component monitors the environmental parameters in the second cavity 16 in real time. When the explosion relief valve 32 is in the closed state, the gas pressure in the second cavity 16 remains relatively stable and there is no specific electrolyte gas. When the explosion relief valve 32 opens due to thermal runaway, the high-pressure gas inside the battery will instantly impact the second cavity 16. The pressure sensor will capture a significant pressure pulse signal. This directly reflects that the explosion relief valve 32 has physically ruptured. At the same time, the gas composition sensor can detect the escaped electrolyte volatiles or pyrolysis gases. The system integrates these signals to confirm that the explosion relief valve 32 is in the open state. This provides a precise trigger signal for subsequent electrolyte injection control.

[0024] For example, see Figure 3 and 4 The housing 1 is also equipped with a second liquid outlet 131 communicating with the second cavity 16. A main liquid inlet pipe 111 is located at the first liquid inlet 11, and the main liquid inlet pipe 111 is connected to the second liquid inlet 13 via a liquid inlet branch pipe 112. A first switching valve is installed on the liquid inlet branch pipe 112. A main liquid outlet pipe 121 is located at the first liquid outlet 12, and the main liquid outlet pipe 121 is connected to the second liquid outlet 131 via a liquid outlet branch pipe 122. A second switching valve is installed on the liquid outlet branch pipe 122. By switching the pipes and valves, the flow direction of the coolant can be flexibly controlled. When it is necessary to inject coolant into the second cavity 16, the first switching valve is opened. Coolant is diverted from the main liquid inlet pipe 111 to the second cavity 16. Simultaneously, the second switching valve and the second liquid outlet 131 can be opened to create liquid circulation within the second cavity 16. The flowing liquid can carry away the heat emitted from the electrode area, preventing heat accumulation at the top of the second cavity 16.

[0025] For example, see Figure 2 and 3 The first cavity 15 is equipped with a positioning plate 5, which has multiple positioning grooves 51 that correspond one-to-one with the battery cells 3. The positioning grooves 51 engage with the bottom of the battery cells 3, and the positioning plate 5 provides support and limits the bottom of the battery cells 3. This prevents the battery from shaking during transportation or under vibration conditions.

[0026] The present invention also provides a control method for an immersion liquid-cooled battery module, applicable to the above-mentioned immersion liquid-cooled battery module, comprising: In normal operating mode, the first inlet 11 is opened to allow coolant to enter the first cavity 15, immersing the bottom of the battery cell 3 for heat exchange, and then exiting through the first outlet 12. During this process, no coolant flows into the second cavity 16. The heat generated by the battery is conducted through the casing to the bottom of the first cavity 15, and the flowing coolant carries the heat out of the housing 1. This ensures that the battery operates within a suitable temperature range and also ensures the insulation safety of the upper high-voltage electrical connections.

[0027] In the thermal runaway handling mode, when thermal runaway of battery cell 3 is detected and the explosion relief valve 32 is opened, the second liquid inlet 13 is opened and coolant is injected into the second cavity 16 through the second liquid inlet 13. The coolant enters the interior of battery cell 3 through the opened explosion relief valve 32. After the system recognizes the danger, it pumps the coolant into the second cavity 16. The coolant level rises and submerges the position of the explosion relief valve 32. Using the injection pressure generated by the pump, the coolant overcomes the air resistance effect and is forcibly injected into the battery through the outlet of the explosion relief valve 32, thereby cooling the interior of battery cell 3.

[0028] For example, in the thermal runaway handling mode, when thermal runaway of battery cell 3 is detected and the explosion relief valve 32 opens, the system first waits for the gas pressure in the second cavity 16 to stabilize before injecting coolant into the second cavity 16. In the initial stage of thermal runaway eruption, the airflow pressure is extremely high. Injecting coolant at this time makes it difficult for the liquid to enter the battery and it is easily dispersed by the airflow. Waiting for the gas pressure to stabilize means avoiding the most intense peak of the jetting. At this time, the outward exhaust resistance inside the battery is reduced. Injecting coolant at this time allows the liquid to enter the battery more easily. This improves the utilization rate of the coolant and the success rate of fire extinguishing.

[0029] For example, the step of determining whether the air pressure in the second cavity 16 has stabilized is as follows: The air pressure value in the second cavity 16 is collected by a pressure sensor at a preset sampling frequency. When the absolute value of the air pressure difference between any two adjacent sampling times is less than a preset stabilization threshold within a preset determination time, it is determined that the air pressure in the second cavity 16 has stabilized, triggering the liquid injection step. For example, the sampling frequency is 1Hz, the preset determination time is 5s, the preset stabilization threshold is 1000Pa, and the preset safety time threshold is 20s. This judgment logic ensures that the air pressure is indeed in a stable state. A small air pressure difference between adjacent times indicates that no new violent eruption has occurred. The system confirms the optimal liquid injection timing through quantified data. This avoids potential errors caused by relying solely on experience.

[0030] For example, while waiting for the gas pressure in the second cavity 16 to stabilize, if the waiting time exceeds a preset safe time threshold (e.g., 20 seconds), the liquid injection step is forcibly triggered. This is a protective mechanism. If the battery continues to release gas in small amounts, causing the gas pressure to remain unstable, the system cannot wait indefinitely. After the safe time has elapsed, the system determines that intervention is necessary. At this point, forced liquid injection may affect the entry efficiency, but cooling can still be achieved through external covering and partial penetration. This prevents the final rescue window from being missed due to excessive waiting.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An immersion liquid-cooled battery module, characterized in that: include: The housing is equipped with a first liquid inlet, a first liquid outlet, a second liquid inlet, and a pressure relief structure; A partition plate is installed inside the box, which divides the interior of the box into a first cavity and a second cavity. The first cavity is located below the second cavity. The first cavity is connected to the first liquid inlet and the first liquid outlet, respectively. The second cavity is connected to the second liquid inlet. The pressure relief structure is used to relieve pressure in the second cavity. The partition plate is provided with multiple mounting holes. Multiple battery cells are inserted into the mounting holes one by one. The battery cells are sealed to the mounting holes, so that the first cavity and the second cavity are isolated from each other. The bottom of the battery cell is located in the first cavity, and the top of the battery cell is provided with an electrode post and a relief valve located in the second cavity. The second inlet is configured to inject coolant into the second cavity after the explosion relief valve is opened, and the coolant can enter the interior of the battery cell through the explosion relief valve.

2. The immersion liquid-cooled battery module according to claim 1, characterized in that: The pressure relief structure is a first pressure relief valve, which is connected to the second cavity. The first pressure relief valve is used to release air when the air pressure in the second cavity exceeds a set value.

3. The immersion liquid-cooled battery module according to claim 2, characterized in that: It also includes a protective box, the box body is housed inside the protective box, and a third cavity is formed between the outer wall of the box body and the inner wall of the protective box. Gas discharged after the first pressure relief valve is opened can enter the third cavity. The protective box is provided with a second pressure relief valve, which is configured to open when the gas pressure in the third cavity rises to a set value, so as to exhaust gas to the outside.

4. The immersion liquid-cooled battery module according to claim 1, characterized in that: The second cavity is equipped with a detection component, which is used to detect the thermal runaway state of the battery cell and the opening state of the explosion relief valve.

5. The immersion liquid-cooled battery module according to claim 1, characterized in that: The housing is also provided with a second liquid outlet communicating with the second cavity. A main liquid inlet pipe is provided at the first liquid inlet. The main liquid inlet pipe is connected to the second liquid inlet through a liquid inlet branch pipe. A first switch valve is provided on the liquid inlet branch pipe. A main liquid outlet pipe is provided at the first liquid outlet. The main liquid outlet pipe is connected to the second liquid outlet through a liquid outlet branch pipe. A second switch valve is provided on the liquid outlet branch pipe.

6. The immersion liquid-cooled battery module according to claim 1, characterized in that: The first cavity is provided with a positioning plate, and the positioning plate is provided with a plurality of positioning grooves corresponding one to one of the battery cells, and the positioning grooves cooperate with the bottom of the battery cells.

7. A control method for an immersion liquid-cooled battery module, applicable to the immersion liquid-cooled battery module as described in any one of claims 1-6, characterized in that: include: In normal operating mode, the first liquid inlet is opened to allow coolant to enter the first cavity through the first liquid inlet, immerse the bottom of the battery cell for heat exchange, and then discharge through the first liquid outlet. In the thermal runaway handling mode, when thermal runaway of the battery cell is detected and the explosion relief valve is opened, the second liquid inlet is controlled to open, and coolant is injected into the second cavity through the second liquid inlet. The coolant enters the interior of the battery cell through the opened explosion relief valve.

8. The control method for the immersion liquid-cooled battery module according to claim 7, characterized in that: In the thermal runaway handling mode, when thermal runaway of the battery cell is detected and the explosion relief valve is opened, the gas pressure in the second cavity is waited for to stabilize before coolant is injected into the second cavity.

9. The control method for the immersion liquid-cooled battery module according to claim 8, characterized in that: The step for determining that the air pressure in the second cavity has stabilized is as follows: the air pressure value in the second cavity is collected by a pressure sensor at a preset sampling frequency. When the absolute value of the air pressure difference between two adjacent sampling times is less than the preset stabilization threshold within a preset determination time, it is determined that the air pressure in the second cavity has stabilized and the liquid injection step is triggered.

10. The control method for the immersion liquid-cooled battery module according to claim 8, characterized in that: If the waiting time exceeds a preset safe time threshold while waiting for the gas pressure in the second cavity to stabilize, the liquid injection step will be forcibly triggered.

Images