Symmetric pulsed immersion liquid cooling thermal management system and method

Abstract

The application discloses a symmetrical pulse immersion liquid cooling heat management system and method, and belongs to the technical field of lithium battery heat management. The system comprises a box body, a pulse inlet controller, a backflow liquid collecting device and a cooling circulating device. The box body is provided with symmetrical double inlets at the top, and is provided with a flow guide plate with partitioned flow guide holes below, the hole diameters of the hole regions are matched with the battery spacings in the box body partitions; the hole diameters of the two side inlet regions are small, and the battery spacings are small; the hole diameters of the central region are large, and the battery spacings are large. The pulse inlet controller controls the cooling liquid in the two inlets to alternately flow in with a phase difference of 160-200 degrees of a sine pulse waveform. Through the synergistic effect of pulse differential flow driving, structure adaptive flow guiding and spacing optimized heat transfer, the application effectively solves the problems of uneven heat dissipation and local overheating of the battery pack, can control the maximum temperature of the battery below 45 DEG C, control the maximum temperature difference within 5 DEG C, and significantly reduces the system operation energy consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery thermal management, in particular to an immersion liquid cooling thermal management system for lithium battery pack, especially large-scale energy storage battery pack and a control method thereof. BACKGROUND

[0002] In recent years, in order to pursue higher power output, the size and capacity of lithium batteries are continuously increasing, and the heat generation and temperature non-uniformity during operation are also significantly increased. Especially in the compact energy storage battery module, local high temperature is easily caused by heat accumulation, which not only accelerates battery aging and leads to inconsistent electrochemical characteristics, but also may induce thermal abuse and even safety accidents.

[0003] Therefore, making the battery work in the appropriate temperature range and maintaining the temperature uniformity in the module has become the key to ensuring the long-term safe operation of the battery. The current mainstream thermal management technology still has obvious limitations:

[0004] The heat dissipation efficiency of air cooling is low, which is difficult to meet the cooling demand of high energy density battery pack;

[0005] In the indirect liquid cooling mode, the liquid cooling plate is usually placed at the bottom of the battery, which is difficult to effectively cool the tab area which is prone to overheating, and may cause excessive temperature difference in the battery monomer;

[0006] The passive cooling technology such as phase change material and heat pipe often needs to be combined with active cooling system, which increases the complexity and cost of the structure.

[0007] Single-phase immersion liquid cooling technology is considered as a promising thermal management solution due to its high heat transfer efficiency, good temperature uniformity and low flow resistance. However, the current research and optimization of this technology mainly focuses on the box structure, the number and position layout of the inlet and outlet, and cannot fundamentally solve the core contradiction between the flow field distribution and the battery thermal load distribution. Since the flow velocity of the cooling liquid in the middle of the battery module is low and the heat exchange is weak, and this area is the area with the highest temperature and the most heat generation, this mismatch easily leads to heat accumulation and local overheating.

[0008] Therefore, there is an urgent need for an immersion liquid cooling solution that can actively adjust the flow field to accurately match the battery pack thermal distribution, thereby achieving efficient heat dissipation while considering temperature uniformity and system energy consumption. SUMMARY

[0009] The present application aims to overcome the shortcomings of the prior art and solve the technical problems of poor temperature uniformity, local overheating and high system energy consumption caused by the mismatch between the flow field and the thermal field in the immersion liquid cooling.

[0010] To address the aforementioned problems, this invention provides a symmetrical pulse immersion liquid-cooled thermal management system, comprising: a housing, a controller, a reflux collection device, and a cooling circulation device;

[0011] The top of the box is symmetrically provided with a first inlet and a second inlet on both sides;

[0012] The box body has a rectifier area below the first inlet and the second inlet, and a guide plate is provided below the rectifier area;

[0013] The guide plate is provided with a plurality of guide holes, and is correspondingly divided into a first hole area near the first inlet, a second hole area near the second inlet, and a third hole area located in the middle. The hole diameters of the first hole area and the second hole area are smaller than the hole diameters of the third hole area.

[0014] The bottom of the box is symmetrically provided with a first outlet and a second outlet on both sides;

[0015] The housing contains a battery pack, which is divided into a first, second, and third battery area according to the hole area of ​​the guide plate. The distance between adjacent batteries in the first and second battery areas is smaller than the distance between adjacent batteries in the third battery area.

[0016] The controller is communicatively connected to the cooling circulation device and is configured to control the coolant at the first inlet and the second inlet to flow in in a sinusoidal pulse manner with a predetermined phase difference.

[0017] Preferably, the predetermined phase difference is 160° to 200°.

[0018] Preferably, the amplitude of the sinusoidal pulse The pulse rate is 15 mL / s to 25 mL / s, with a pulse period of... It lasts from 50 to 70 seconds.

[0019] Preferably, the guide holes on the guide plate are distributed in 2 rows × 3 columns, the diameter d1 of the guide holes in the first and second hole areas is 6 mm, and the diameter d2 of the guide holes in the third hole area is 10 mm.

[0020] Preferably, the battery pack is fixed by a spacing adjustment device, which includes two slide rods and a plurality of clips slidably fitted on the slide rods, the clips being used to clamp and fix adjacent batteries.

[0021] Preferably, the slide bar is provided with a slot, and the clamping piece is positioned through the slot.

[0022] Preferably, the outlet of the cooling circulation device is connected to the first inlet and the second inlet respectively via pipelines, and its inlet is connected to the outlet of the reflux collection device via pipelines.

[0023] Preferably, the cooling liquid is an insulating fluorinated liquid.

[0024] In another aspect, the present application also provides a liquid cooling thermal management method for the above-mentioned system, comprising the following steps:

[0025] S1. issuing an instruction through the pulse inlet controller to drive the cooling liquid to flow into the box alternately from the first inlet and the second inlet in a sinusoidal pulse waveform with a phase difference of 160° to 200°;

[0026] S2. After the cooling liquid is rectified in the rectification area, it flows into the corresponding battery area through the guide holes of the guide plate and exchanges heat with the battery pack;

[0027] S3. The cooling liquid that has completed heat exchange flows out through the first outlet and the second outlet and is collected by the backflow collecting device;

[0028] S4. The cooling liquid in the backflow collecting device is sent to the cooling circulation device for cooling and completes the circulation.

[0029] Preferably, in step S1, the amplitude of the sinusoidal pulse waveform is 15 mL / s to 25 mL / s, and the pulse period is 50 s to 70 s.

[0030] Compared with the prior art, the present application realizes a significant improvement in the comprehensive performance of lithium battery pack thermal management through the effective synergy of pulse differential flow driving, structure-adapted flow guiding, and optimized heat transfer distance. First, in terms of temperature control, the non-uniform battery spacing design increases the flow channel space in the high-heat-load center area, and the precise distribution of the cooling liquid by the partitioned flow guide holes, thereby fundamentally optimizing the matching relationship between the flow field and the thermal field, so that the maximum temperature difference of the battery pack can be effectively controlled within 5℃. Secondly, in terms of system energy efficiency, due to the use of the phase-difference pulse flow strategy, the system can utilize the inertial effect of the fluid to alternately form strong and weak convection stages, which not only strengthens the heat transfer process, but more importantly, significantly reduces the average flow rate and pumping energy consumption of the system, achieving a balance between efficient heat dissipation and low operating power consumption.

[0031] As a result, pulse flow provides a dynamic optimization power source for the system, partitioned flow guiding structure ensures precise flow guidance, and non-uniform spacing creates an optimal heat exchange space for the differentiated flow field. The three work together to form an organic whole, providing a high-efficiency, uniform, and energy-saving thermal management solution. BRIEF DESCRIPTION OF DRAWINGS

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0033] Figure 1 This is a schematic diagram of the overall structure of the immersion liquid-cooled thermal management system in the embodiment;

[0034] Figure 2 This is a schematic diagram of the assembly structure of the casing and battery pack in the embodiment;

[0035] Figure 3 for Figure 2 Exploded view of the structure shown;

[0036] Figure 4 This is a schematic diagram of the spacing adjustment device in the embodiment;

[0037] Figure 5 This is a schematic diagram of the battery pack's compartments.

[0038] Figure 6 (a) is a temperature distribution cloud map inside the chamber during the simulation experiment of the thermal control scheme of the embodiment;

[0039] Figure 6 (b) in the figure is a statistical diagram of the highest temperature and maximum temperature difference of the battery pack during the simulation experiment of the thermal control scheme of the embodiment;

[0040] In the diagram: 1. Pulse inlet controller; 2. Housing; 3. Reflux collection device; 4. Cooling circulation device; 5. Battery pack; 6. Guide hole; 7. Rectifying zone; 8a. First inlet; 8b. Second inlet; 9. Guide plate; 10a. First outlet; 10b. Second outlet; 11. Spacing adjustment device; 12. Slide bar; 13. Clamping plate. Detailed Implementation

[0041] This invention aims to provide a symmetrical pulse immersion liquid cooling thermal management system and method that can effectively solve the problems of uneven heat dissipation and localized overheating in battery packs. Two specific embodiments of the invention will be described in detail below with reference to the accompanying drawings to enable those skilled in the art to better understand and implement the invention. It should be noted that the specific parameters, dimensions, and materials mentioned in the following description are merely illustrative and do not constitute a limitation on the scope of protection of this invention.

[0042] Example 1:

[0043] This embodiment provides a symmetrical pulse immersion liquid-cooled thermal management system.

[0044] Please see Figures 1 to 4The system includes a housing 2, a pulse inlet controller 1, a reflux collection device 3, and a cooling circulation device 4. The housing 2 is typically made of a material with good thermal conductivity and corrosion resistance, such as aluminum alloy or stainless steel, and its interior forms a sealed cavity to house the coolant and battery pack. A first inlet 8a and a second inlet 8b are symmetrically located on the top sides of the housing 2. The axes of these two inlets are on the same horizontal plane and symmetrically distributed about the longitudinal central axis of the housing. This symmetrical layout is a key design feature to structurally prevent uneven initial distribution of the coolant.

[0045] Directly below the first inlet 8a and the second inlet 8b, an upper rectification zone 7 is formed inside the housing 2, such as... Figure 3 As shown, the rectifier zone 7 can be an independent chamber enclosed by the guide plate 9 and the upper outer shell of the housing 2. Its function is to initially stabilize and guide the coolant flowing in from the first inlet 8a and the second inlet 8b, which may have a turbulent flow pattern. The guide plate 9 is horizontally fixedly installed below the upper rectifier zone 7, and multiple guide holes 6 are machined on the guide plate 9 to penetrate its body.

[0046] It should be noted that these guide holes 6 are not evenly distributed, but are zoned according to the heat load distribution of the battery below them. Specifically, the guide plate 9 can be divided into three functional areas: the first hole area near the first inlet 8a, the second hole area near the second inlet 8b, and the third hole area located in the middle of the guide plate 9.

[0047] After passing through the guide holes 6 on the guide plate 9, the coolant forms multiple jets that impact the surface of the battery pack 5 below. This jet impact effectively breaks down the thermal boundary layer on the battery surface, thereby significantly enhancing convective heat transfer. The average heat transfer coefficient of the battery impact surface is... It can be estimated using the classic jet impingement heat transfer correlation, which indicates the average Nusselt number. It is a function with multiple dimensionless parameters, specifically defined by the formula. Description. Among them, This represents the diameter of guide hole 6. This represents the vertical distance from the outlet of guide hole 6 to the battery impact surface. This represents the spacing between adjacent guide holes. Based on the diameter of the guide hole 6 The Reynolds number calculated from the outlet flow velocity, This is the Prandtl number of the coolant. From this formula, it can be clearly seen that, under the condition that the coolant properties and system geometry are roughly determined, the average heat transfer coefficient h of the battery surface... m Mainly affected by the diameter of the guide hole The impact of this is one of the core theoretical bases for the partitioned aperture design of the guide plate 9 in this embodiment. Therefore, by using a larger guide hole diameter d2 (e.g., 10mm) in the third hole area corresponding to the high heat dissipation demand area, compared to using a smaller guide hole diameter d1 (e.g., 6mm) in the side areas, the heat transfer capacity of the impinging jet in this area can be directly improved, thereby more effectively strengthening the heat dissipation intensity of the central area and matching it with the battery heat generation distribution.

[0048] On both sides of the bottom of the housing 2, a first outlet 10a and a second outlet 10b are symmetrically provided. After heat exchange with the battery pack 5, the coolant collects at the bottom of the housing 2 under the influence of flow field and gravity, and is discharged through the symmetrically distributed first outlet 10a and second outlet 10b. The discharged coolant is transported to the return collection device 3 for collection and temporary storage via pipeline. The return collection device 3, as an independent container, has the core function of collecting all the coolant flowing out of the housing and acts as a buffer unit to ensure that the subsequent cooling circulation device 4 can stably draw working fluid.

[0049] The reflux collection device 3 typically consists of a sealed tank with one or more collection chambers inside. The upper part of the tank has one or more inlet connectors, which are connected via pipelines to the first outlet 10a and the second outlet 10b of the housing 2, respectively, for receiving the warm working fluid. The bottom or lower part of the tank has an outlet connector, which is connected via pipelines to the inlet of the cooling circulation device 4, so that the collected coolant can be pumped to subsequent cooling units.

[0050] To ensure reliable system operation, the tank is typically equipped with auxiliary components such as a liquid level observation window, a liquid level sensor interface, and an exhaust valve. These components monitor the liquid level and remove any gas that may accumulate in the system, thereby maintaining the stability and safety of the cooling circuit. The choice of materials must also consider compatibility with the coolant; for example, stainless steel or corrosion-resistant engineering plastics can be used.

[0051] The core of the casing 2 is the battery pack 5, which consists of multiple individual cells, such as 16 square lithium iron phosphate batteries, arranged in a specific pattern. Figure 5 As shown, the battery pack 5 also employs a non-uniform spacing design, with its zones corresponding one-to-one with the guide vane holes above. In other words, battery pack 5 is also divided into a first battery zone, a second battery zone, and a third battery zone. The first and second battery zones, being closer to the coolant inlet, have lower coolant temperatures and relatively easier-to-maintain flow rates; therefore, the spacing between adjacent batteries in these zones is set smaller. Figure 5The area defined by X1 is shown; the third battery area is located in the center, where heat dissipation conditions are most unfavorable. Therefore, the spacing between adjacent batteries is set significantly larger to reduce flow resistance, guide more coolant to flow through, and thus enhance heat dissipation. Figure 5 The region defined by X3 is shown.

[0052] In a preferred embodiment, the battery spacing in the central region is 30% to 50% larger than the battery spacing in the entrance region. To achieve this adjustable, non-uniform battery spacing, this embodiment employs a dedicated spacing adjustment device 11. Figure 4 As shown, the device mainly includes two parallel sliding rods 12 and multiple clips 13 that are slidably sleeved on the sliding rods 12.

[0053] The two ends of the slide rod 12 can be fixed to the bottom of the inner side of the housing 2 by any known fixing method such as bolts, snap-fit, or welding. Each slide rod 12 has continuous slots machined along its length. The clamping piece 13 can be flat and is usually made of engineering plastic. It can be inserted vertically into the slot to form a battery clamping and mounting area between two adjacent clamping pieces 13. By flexibly adjusting the insertion position of the clamping piece 13 along the length of the slide rod 12 and tightening it, the spacing of the batteries in different sections can be accurately set and fixed, making the operation simple, flexible, and reliable.

[0054] In this embodiment, the pulse inlet controller 1 is the control core of the entire thermal control system. It is usually a microprocessor or PLC controller and establishes a communication connection with the cooling circulation device 4 through a signal line.

[0055] The cooling circulation device 4 is an integrated device that includes a circulation pump, a heat exchanger, a liquid storage tank, and necessary valves and pipelines. It should be noted that the cooling circulation device 4 in this embodiment can be any commercially available cooling circulation device, as long as it can meet the cooling and control tasks of the coolant flowing out of the box 2 in this embodiment. Its specific structure and cooling principle will not be described in detail in this embodiment.

[0056] The outlet of the cooling circulation device 4 is connected to the first inlet 8a and the second inlet 8b of the housing 2 via two independent pipelines, while its inlet is connected to the outlet of the return liquid collection device 3 via a main pipeline.

[0057] The pulse inlet controller 1 is programmed to send control commands to the circulation pump in the cooling circulation device 4, driving the coolant to flow into the housing 2 from the first inlet 8a and the second inlet 8b in a specific sinusoidal pulse waveform with a predetermined phase difference.

[0058] The flow velocity of the sinusoidal pulse is defined by a specific mathematical formula, wherein the flow velocities at the two inlets are... and Calculated using the following formulas respectively:

[0059] ;

[0060] .

[0061] In these formulas, Represents the average flow velocity. Represents pulse amplitude. Represents the pulse period. This represents the time elapsed since the system started.

[0062] To achieve the best effect of alternating strong and weak convection, the phase difference is preferably set between 160° and 200°, with the ideal state being 180°. The curvature allows for alternating strong and weak convection cooling stages at the two inlets, thereby enhancing heat transfer while reducing energy consumption.

[0063] Pulse amplitude and cycle The specific value needs to be selected based on the battery's heat generation capacity and the desired temperature control target, such as amplitude. The selectable range is 15 mL / s to 25 mL / s, with a cycle time of... The selectable range is 50s to 70s.

[0064] In a preferred combination of parameters, the amplitude Set to 20 mL / s, period It was set to 60s, and the phase difference was set to 180°.

[0065] The choice of coolant is also crucial. A liquid with high insulation, high thermal conductivity, low viscosity and chemical stability must be used, such as fluorinated liquid HFE-7100 or similar electronic engineering fluids, to ensure the absolute safety of the battery in immersion environments.

[0066] In summary, the system of this embodiment forms a complete thermal management system by constructing an integrated submersible enclosure 2 driven by a pulse inlet controller, comprising symmetrical dual inlets, partitioned guide plates, non-uniformly spaced battery packs, and symmetrical dual outlets, and by achieving coolant circulation through an external loop. Its usage is as follows:

[0067] After system startup, the pulse inlet controller 1 controls the cooling circulation device 4 according to preset sinusoidal pulse parameters. Coolant is pumped into the inlets on both sides of the top of the housing 2, where it undergoes initial flow stabilization in the upper rectifying zone 7 before impacting the guide plate 9. The coolant then flows through the guide holes 6 in different sections of the guide plate 9. Due to the difference in hole diameter, the flow rate is redistributed, with more coolant being guided to the area below the large-diameter hole in the center. The coolant impacts into the battery immersion chamber in a jet-like manner, making full contact with the surface of the battery pack 5 arranged at non-uniform intervals and exchanging heat. During this process, the larger battery spacing in the central area provides a lower flow resistance channel, working in conjunction with the larger guide holes 6 above to ensure sufficient coolant flows to the areas most in need of heat dissipation. Finally, the heated coolant, driven by gravity and flow, collects at the bottom of the housing and exits through the outlets on both sides. After being collected by the return collection device 3, it returns to the cooling circulation device 4 for cooling. The cooled coolant is then pumped back into the housing 2, and the cycle repeats continuously.

[0068] Example 2:

[0069] This embodiment provides a symmetrical pulse immersion liquid cooling thermal management system based on the system described in Embodiment 1.

[0070] First, a precise control command is sent to the cooling circulation device 4 through the pulse inlet controller 1. The core of this command is to drive the pump in the cooling circulation device 4 so that the coolant output by it flows into the housing 2 alternately and periodically from the first inlet 8a and the second inlet 8b of the system in a specific sinusoidal pulse waveform pattern with a phase difference.

[0071] The mathematical expression of the sinusoidal pulse waveform is strictly defined by the following two formulas:

[0072] Flow rate at the first inlet From the formula calculate;

[0073] Flow rate at the second inlet From the formula calculate.

[0074] Following step S2, the pulsed coolant flowing in from the two inlets with a phase difference converges and undergoes sufficient momentum exchange and rectification within the upper rectifying zone 7 of the housing 2, effectively suppressing flow non-uniformity. Subsequently, the pre-rectified coolant, driven by pressure, passes through the guide holes 6 on the guide plate 9, forming multiple jets that impact the surface of the battery pack 5 below. The average heat transfer coefficient of the battery impact surface... It can be estimated based on the classic jet impingement heat transfer correlation, which is derived from the formula... The formula, as described, theoretically reveals the key geometric and flow parameters that affect the heat transfer intensity.

[0075] Because the guide plate adopts a zoned differentiated aperture design—that is, the aperture d1 of the guide holes 6 in the first and second aperture zones is smaller than the aperture d2 of the guide holes 6 in the third aperture zone—the coolant flow is precisely redistributed. More fluid is directed to the area below the third aperture zone corresponding to the central region of the battery pack 5, directly increasing the impact heat transfer coefficient of this region according to the aforementioned relationship. After passing through the guide holes 6, the coolant enters the battery immersion chamber, directly contacting and undergoing forced convection heat transfer with the surface of the battery pack 5. The battery pack 5 has been pre-set with a non-uniform spacing via the spacing adjustment device 11, meaning the spacing between the first and second battery zones is smaller, while the spacing between the third battery zone is larger. This provides a smoother flow path for the coolant in the central region with the highest heat load, further optimizing the matching of the flow field and the thermal field.

[0076] Then, in step S3, after heat exchange with the battery, the cooled liquid, now at a higher temperature, flows downwards under the combined influence of the flow field and gravity. It eventually exits the tank 2 through the first outlet 10a and the second outlet 10b, symmetrically located at the bottom of the tank 2, and enters the return collection device 3 for temporary collection and storage. Finally, in step S4, the warm cooled liquid collected in the return collection device 3 is pumped to the cooling circulation device 4. Inside this device, the cooled liquid flows through a heat exchanger, and the heat it carries is carried away by the cooling loop, thus lowering its temperature to a preset suitable temperature, such as 22°C. The cooled working fluid regains its cooling capacity and is then pumped back to the inlet at the top of the tank 2, thus forming a complete, closed-loop cooling cycle.

[0077] In summary, the method provided in this embodiment achieves efficient battery thermal management by precisely controlling the inflow process of sinusoidal pulses with a specific phase difference and cleverly utilizing the downstream partitioned flow guiding structure and inconsistent battery spacing layout to optimize the flow field distribution. It significantly improves the temperature uniformity of the battery pack 5 during operation. Simulation and test data both demonstrate that it can reliably control the maximum temperature difference of the battery modules within the stringent target of 5°C, thereby effectively delaying uneven aging of the battery pack caused by temperature inconsistencies. Secondly, while ensuring excellent heat dissipation performance, this method also exhibits superior energy-saving characteristics. Due to the use of a non-constant pulsed flow supply, the average flow rate of the system per unit time is reduced, which directly translates into a decrease in the power consumption of the circulating pump, achieving the dual goals of efficient heat dissipation and low operating costs.

[0078] To verify the effectiveness of the system and method described in Embodiments 1 and 2, we used COMSOL multiphysics simulation software to numerically simulate the heat dissipation process of the battery module.

[0079] The specific settings for the simulation experiment are as follows:

[0080] A module model containing 16 square lithium-ion batteries was established, with each battery cell having a rated capacity of 100Ah. The volumetric heat generation rate was set to a constant value during discharge at 1C. A fluorinated liquid with excellent insulation and thermal conductivity was selected as the coolant, and its inlet temperature was kept constant at 22℃.

[0081] The specific experimental parameters were set strictly according to the aforementioned optimal values: the coolant flow rates at the two inlets followed a sinusoidal pulse function with a phase difference of π, and the pulse amplitude... Set to 20 mL / s, pulse period The time is set to 60 seconds. The diameter d1 of the guide holes in the first and second hole areas of the internal partition guide plate 9 of the housing 2 is set to 6 mm, and the diameter d2 of the guide holes in the third hole area is set to 10 mm. The spacing of the inlet area of ​​the battery pack 5 is 4 mm, and the spacing of the center area is set to 1.4 times the spacing of the inlet area.

[0082] The simulation results clearly demonstrate the significant advantages of the thermal control scheme in thermal management performance of the embodiment.

[0083] In this embodiment, the coolant flow field is uniformly distributed, the inertial effect generated by the pulsed flow enhances the fluid's penetration and mixing capabilities, the partitioned guide vanes precisely direct more coolant to the central region, and the increased battery spacing further reduces the flow resistance in this area. These three factors work together to ensure that the coolant effectively covers and cools each battery cell, thereby achieving optimal cooling performance. Figure 6 The temperature distribution cloud map shown in (a) presents a uniform blue or green color overall, with no local hot spots.

[0084] See also Figure 6 As shown in (b), the peak temperature of the battery module was effectively suppressed after adopting a synergistic design that combined phase difference pulse inflow, zoned current diversion, and non-uniform battery spacing. Throughout the discharge process, the peak temperature was consistently controlled below the safe target temperature of 45°C, completely eliminating the risk of local overheating. The maximum temperature difference of the battery module was also successfully controlled within 5°C, achieving extremely high temperature consistency.

[0085] The above results fully demonstrate that the thermal control scheme of the embodiment, by actively adjusting the flow field to precisely match the thermal distribution of the battery pack, is correct and efficient. It effectively solves the core technical challenges of uneven heat dissipation and localized overheating in high-energy-density battery packs. Furthermore, due to the use of pulsed current supply, while achieving the aforementioned excellent thermal management effects, the system's operating energy consumption is also reduced.

Claims

1. A symmetric pulsed immersion liquid cooling thermal management system, characterized by: The box (2), the controller (1), the backflow collecting device (3) and the cooling circulation device (4); The box (2) is provided with a first inlet (8a) and a second inlet (8b) on both sides of the top; The box (2) is provided with a rectifier area (7) below the first inlet (8a) and the second inlet (8b), and a guide plate (9) below the rectifier area (7); The guide plate (9) is provided with a plurality of guide holes (6), and is divided into a first hole area close to the first inlet (8a), a second hole area close to the second inlet (8b), and a third hole area in the middle; The box (2) is provided with a first outlet (10a) and a second outlet (10b) on both sides of the bottom; The box (2) is provided with a battery pack (5), and the battery pack (5) is divided into first, second and third battery areas in a manner corresponding to the hole areas of the guide plate (9), the adjacent battery spacing of the first and second battery areas is smaller than that of the third battery area, and the adjacent battery spacing of the third battery area is 30%-50% larger than that of the first and second battery areas; The controller (1) is in communication connection with the cooling circulation device (4), and is configured to control the cooling liquid flow rate of the first inlet (8a) and the second inlet (8b) to flow in a sinusoidal pulse manner with a predetermined phase difference; The predetermined phase difference is 160°-200°; The amplitude of the sinusoidal pulse is 15mL / s to 25mL / s, and the pulse period is 50s to 70s; The guide holes (6) on the guide plate (9) are distributed in 2 rows and 3 columns, the hole diameter d1 of the guide holes in the first and second hole areas is 6mm, and the hole diameter d2 of the guide holes in the third hole area is 10mm.

2. The symmetrical pulsed immersion liquid cooling thermal management system of claim 1, wherein: The battery pack (5) is fixed by a spacing adjusting device (11), the spacing adjusting device (11) includes two slide rods (12) and a plurality of clamping pieces (13) slidably sleeved on the slide rods (12), and the clamping pieces (13) are used for clamping and fixing adjacent batteries.

3. The symmetrical pulsed immersion liquid cooling thermal management system of claim 2, wherein: The slide rod (12) is provided with a clamping groove, and the clamping piece (13) is positioned by the clamping groove.

4. The symmetrical pulsed immersion liquid cooling thermal management system of claim 1, wherein: The outlet of the cooling circulation device (4) is connected to the first inlet (8a) and the second inlet (8b) through pipelines, and the inlet is connected to the outlet of the backflow collecting device (3) through a pipeline.

5. The symmetrical pulsed immersion liquid cooling thermal management system of claim 1, wherein: The cooling liquid is an insulating fluorinated liquid.

6. Symmetrical pulsed immersion liquid cooling thermal management method for the system of any of claims 1-5, characterized in that, The method comprises the following steps: S1. The pulse inlet controller (1) sends instructions to drive the cooling liquid flow rate to flow into the box (2) from the first inlet (8a) and the second inlet (8b) in a sinusoidal pulse waveform with a phase difference of 160° to 200°; S2. After the cooling liquid is rectified in the rectifier area (7), it flows into the corresponding battery area through the guide holes (6) of the guide plate (9) and exchanges heat with the battery pack (5); S3. The cooling liquid, which has completed heat exchange, flows out through the first outlet (10a) and the second outlet (10b) and is collected by the backflow collecting device (3); S4. The cooling liquid in the backflow collecting device (3) is sent to the cooling circulating device (4) for cooling and completes circulation.

7. The symmetrical pulsed immersion liquid cooling thermal management method of claim 6, wherein: In step S1, the amplitude of the sinusoidal pulse waveform is 15 mL / s to 25 mL / s, and the pulse period is 50 s to 70 s.

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