Immersed liquid cooling energy storage power station thermal management system combining inverse opal structure surface and bionic heat pipe

Abstract

The invention discloses an immersed liquid cooling energy storage power station thermal management system combined with an inverse opal structure surface and a bionic heat pipe, and relates to the technical field of immersed liquid cooling of energy storage power stations. Cooling liquid flows in a direction which is vertical to the surface of a heat conduction layer in the overall flowing direction and is locally parallel to the surface of the heat conduction layer and rapidly skims over the surface of a single battery; convection heat exchange with the battery monomers is carried out, a large amount of heat is absorbed, and the battery temperature is reduced. Meanwhile, when immersed liquid cooling is carried out, the evaporation ends of the loop heat pipes between the adjacent battery monomers are in direct contact with the surfaces of the battery monomers to absorb heat and exchange heat with the cooling liquid flowing in the liquid cooling box body, and the two cooling modes are coupled, so that the overall cooling efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of immersed liquid cooling of energy storage power stations, and in particular to an immersed liquid cooling energy storage power station thermal management system combining an inverse opal structure surface and a bionic heat pipe. Background Art

[0002] The energy storage power station is equivalent to the "power bank" of the city. It uses renewable energy such as wind energy and solar energy to generate electricity, and converts excess electrical energy into chemical energy and stores it in energy storage batteries when the power grid is in a low power consumption period. When the power grid is in a peak power consumption period, the chemical energy stored in the energy storage batteries is converted into electrical energy for discharge, participating in peak load and frequency regulation and playing a role in peak shaving and valley filling.

[0003] However, lithium-ion batteries have relatively strict requirements for operating temperature. Too high or too low temperature will significantly reduce the working performance of lithium-ion batteries and even cause safety problems. In energy storage power stations, large-scale battery energy storage systems have higher battery array density and complex operating conditions. If the heat dissipation problem cannot be effectively solved, the working efficiency of the battery system will be seriously affected. In extreme cases, it may even cause safety accidents such as thermal runaway of battery cells and fire and explosion of battery systems. Therefore, effective thermal management technology is an important guarantee to ensure the safe and efficient operation of energy storage battery systems.

[0004] At present, energy storage power stations mostly use air cooling and indirect liquid cooling solutions. For air cooling systems, the power generation capacity of the power system will be significantly reduced when the wind speed is unstable or the wind is too weak, and the air cooling performance is affected by its own characteristics, and there are problems such as insufficient cooling capacity and low safety. Liquid cooling technology can be divided into indirect liquid cooling technology and direct liquid cooling technology. Direct liquid cooling technology has developed rapidly in recent years, and immersion liquid cooling technology is a typical direct liquid cooling technology. Immersion cooling abandons the cold plate, so that the battery is in direct contact with the immersion coolant, and the self-generated heat of the battery is efficiently, quickly and timely transferred. Compared with indirect cold plate cooling, direct immersion cooling theoretically has smaller thermal resistance, higher cooling efficiency and better temperature uniformity. However, immersion liquid cooling technology has corresponding limitations. In extreme cases such as high temperature weather or high-intensity operation of energy storage power stations, the cooling effect is not enough to keep the lithium battery in the best working state; the capacity is reduced in the harsh low temperature environment, and the charging and discharging power is limited; at the same time, the lithium battery is in direct contact with the liquid and it is easy to change its structure, which poses certain safety hazards.

[0005] Two-phase liquid cooling technology mainly dissipates heat based on the phase change principle of the heat exchange medium. Compared with single-phase flow, two-phase flow can absorb or release a large amount of heat during the phase change process, which makes the two-phase flow have higher heat transfer performance. At the same time, due to the existence of the gas-liquid interface, there is a better mixing effect between the two-phase fluids. However, when the critical heat flux density is reached, the coolant will produce a steam film on the battery contact surface, hindering the transfer of heat, and then leading to the boiling limit problem.

[0006] In view of the above research situation, there is an urgent need to design an immersion thermal management system suitable for energy storage power stations to provide better protection for the safety and efficient use of electric energy. Summary of the invention

[0007] In order to overcome the deficiencies of the above technologies, the present invention provides an immersion liquid cooling energy storage power station thermal management system combining an inverse opal structure surface and a bionic heat pipe, which improves the heat exchange efficiency of immersion liquid cooling.

[0008] The technical solution adopted by the present invention to overcome the technical problems is: A thermal management system for an immersion-type liquid-cooled energy storage power station combining an inverse opal structure surface and a bionic heat pipe, comprising: The liquid cooling plate has a sealed liquid cooling chamber I inside, and a liquid cooling box is buckled on the upper end thereof, and the liquid cooling box and the liquid cooling plate form a sealed liquid cooling chamber II; N battery modules are fixed on the liquid cooling plate, each battery module is composed of M battery cells fixed by a fixing device; P outwardly protruding topological fins are respectively arranged on the front and rear surfaces of every two battery cells, and a heat-conducting layer is arranged on the front and rear surfaces of the battery cells and the surfaces of each topological fin, and the outer end of each heat-conducting layer is in contact with the evaporation end of the loop heat pipe; The condensing end of each loop heat pipe is embedded in the liquid cooling cavity I of the liquid cooling plate, one end of the condensing end is connected to one end of the corresponding evaporating end through a steam channel, and the other end is connected to the other end of the corresponding evaporating end through a liquid channel; A coolant supply system I, disposed on the liquid cooling plate, for supplying coolant into the liquid cooling chamber I; and The coolant supply system II is arranged on the liquid cooling box body and is used for inputting the coolant into the liquid cooling cavity II.

[0009] Furthermore, the liquid cooling plate is provided with N×M slots, and the bottom of each battery cell is inserted into the corresponding slot.

[0010] Preferably, the value of N is 2, and the two battery modules are parallel to each other.

[0011] Furthermore, the fixing device is an annular steel belt, which is bundled around the periphery of each battery cell.

[0012] In order to prevent damage to the battery cells, end plates are attached to the left and right ends of each battery module.

[0013] Furthermore, the thermal conductive layer is made of an inverse opal structure material.

[0014] Furthermore, the cooling liquid supply system I includes a liquid cooling plate inlet arranged at the left end of the liquid cooling plate and a liquid cooling plate outlet arranged at the right end. The liquid cooling plate inlet and the liquid cooling plate outlet are both connected to the liquid cooling chamber I. The liquid cooling plate inlet is connected to the outlet end of the cooling liquid pump, and the liquid cooling plate outlet is connected to the inlet end of the cooling liquid pump.

[0015] Furthermore, the coolant supply system II includes a liquid inlet arranged at the front end of the liquid cooling box and a liquid outlet arranged at the rear end of the liquid cooling box. The axis of the liquid inlet and the axis of the liquid outlet are perpendicular to the surface of the battery cell. The liquid inlet is connected to the outlet end of the coolant pump, and the liquid outlet is connected to the inlet end of the coolant pump.

[0016] Furthermore, the number and shape of the above-mentioned topological fins are obtained by topologically optimizing the battery surface ribs using COMSOL software with the highest comprehensive heat transfer coefficient in the heat transfer process of the coolant flowing over the battery cell surface and with the minimum pressure drop as the optimization goal.

[0017] In order to improve the heat exchange efficiency, a number of blocking plates are arranged at intervals along the axial direction on the left and right sides of the liquid channel of the loop heat pipe. The blocking plates are of a triangular structure, and the blocking plates on the left side of the liquid channel and the blocking plates on the right side of the liquid channel are symmetrically arranged in an eight-shaped shape.

[0018] The beneficial effects of the present invention are: (1) The present invention takes the battery surface as the design domain, performs topological optimization by taking into account flow loss and heat transfer enhancement, and arranges P irregular topological fins on each side of the battery surface, so that when the coolant with the same flow rate passes through, the average surface temperature and comprehensive thermal resistance of the battery cell after adding the topological fins are lower than those of the traditional structure. At the same time, through topological optimization, the inlet and outlet pressure drop is reduced, and the consumption of pump power is reduced. Therefore, the topological optimization of the battery cell surface makes it superior to the traditional battery structure in terms of comprehensive performance such as energy consumption and heat dissipation, and improves the heat exchange efficiency of immersion liquid cooling.

[0019] (2) The present invention arranges circulating heat pipes between battery cells. The evaporation end of the circulating heat pipe directly contacts the heat conductive layer and is assisted by coolant convection heat exchange. The condensation end of the circulating heat pipe is placed in the bottom liquid cooling plate to reduce the size of the box, making the overall layout compact and efficient. At the same time, the curved design can optimize the flow area of ​​the liquid cooling plate. In view of the uneven battery temperature, the evaporation end of the heat pipe is arranged away from the liquid cooling plate to improve the temperature uniformity. The system integrates immersion liquid cooling, heat pipe cooling and liquid cooling plate to form an efficient thermal management system, forming a cooling system with immersion liquid cooling as the main and heat pipes and liquid cooling plates as the auxiliary, and a heating system with liquid cooling plates as the main heating and heat pipes as the auxiliary heat conduction.

[0020] (3) In the present invention, since the condensation end is located below the evaporation end, the liquid at the condensation end needs to overcome the gravity and return to the evaporation end. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 It is a three-dimensional structural diagram of the evaporation end portion of the present invention; Figure 3 It is a front cross-sectional view of the condensation end of the present invention; Figure 4 It is a structural diagram of the topological fin part of the present invention; Figure 5 The working principle and structural diagram of the heat-conducting layer of the present invention; Figure 6 It is a three-dimensional structural diagram of the battery cell of the present invention; Figure 7 is a three-dimensional structural diagram of a loop heat pipe of the present invention; Figure 8 is a cross-sectional structural diagram of the liquid channel of the present invention; Fig. 9 A comparison diagram of the average temperature of the topological battery surface of the present invention and the other two surface structures as a function of the inlet velocity; Fig.10 A comparison diagram of the average temperature of the topological battery surface of the present invention and the other two surface structures as the pump work changes; In the figure, 1. liquid cooling box 2. liquid cooling plate 3. liquid inlet 4. liquid outlet 5. liquid cooling plate inlet 6. liquid cooling plate outlet 7. evaporation end 8. liquid channel 9. steam channel 10. condensation end 11. topological fins 12. heat conductive layer 13. battery cell 14. end plate 15. steel belt 16. barrier sheet. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1 To Attachment Fig.10 The present invention is further described.

[0023] As attached Figure 1 , Attachment Figure 2 , Attachment Figure 3 , Attachment Figure 4 , Attachment Figure 6 , Attachment Figure 7As shown, an immersion type liquid-cooled energy storage power station thermal management system combining an inverse opal structure surface and a bionic heat pipe comprises: a liquid cooling plate 2, which has a closed liquid cooling cavity I inside, and a liquid cooling box 1 is buckled on the upper end thereof, and the liquid cooling box 1 and the liquid cooling plate 2 form a closed liquid cooling cavity II; N battery modules are fixed on the liquid cooling plate 2, and each battery module is composed of M battery cells 13 and fixed by a fixing device; the front surface and the rear surface of each two battery cells 13 are respectively provided with P outwardly protruding topological ribs 11, and the front surface, the rear surface and each topological rib 11 of the battery cell ... 11, and the front surface, the rear surface and each topological rib 11 of the battery cell 13 are respectively provided with P outwardly protruding topological rib 11, and the front surface, the rear surface and each topological rib 11 of the battery cell 13 are respectively provided with P outwardly protruding topological rib 11, and the front surface, the rear surface and each topological rib 11 of the battery cell 13 are respectively provided with P outwardly protruding topological rib 11, and the front surface, The surface of the sheet 11 is provided with a heat-conducting layer 12, and the outer end of each heat-conducting layer 12 is in contact with the evaporation end 7 of the loop heat pipe; the condensation end 10 of each loop heat pipe is embedded in the liquid cooling cavity I of the liquid cooling plate 2, one end of the condensation end 10 is connected to one end of the corresponding evaporation end 7 through the steam channel 9, and the other end thereof is connected to the other end of the corresponding evaporation end 7 through the liquid channel 8; the cooling liquid supply system I is provided on the liquid cooling plate 2, and is used to input the cooling liquid into the liquid cooling cavity I; and the cooling liquid supply system II is provided on the liquid cooling box 1, and is used to input the cooling liquid into the liquid cooling cavity II. The cooling liquid is input into the liquid cooling cavity II through the cooling liquid supply system II, and the cooling liquid flows perpendicularly to the surface of the heat-conducting layer 12 in the overall flow direction, and flows in a direction partially parallel to the surface of the heat-conducting layer 12 and quickly passes over the surface of the battery cell 13, and performs convection heat exchange with the battery cell 13, absorbing a large amount of heat and reducing the battery temperature. At the same time, while the immersion liquid cooling is being performed, the evaporation end 7 of the loop heat pipe between the adjacent battery cells 13 directly contacts the surface of the battery cells 13 to absorb heat, and at the same time exchanges heat with the coolant flowing in the liquid cooling box 1. The two cooling methods are coupled to greatly improve the overall cooling efficiency. After absorbing heat, the evaporation end 7 heats the refrigerant in the loop heat pipe into steam, which then enters the condensation chamber 17 through the steam channel 9. The coolant is input into the liquid cooling plate 2 through the coolant supply system I to exchange heat with the condensation end 10 of each loop heat pipe. After the coolant is cooled, it becomes liquid and flows back to the evaporation end 7 through the liquid channel 8 to achieve circulation.

[0024] In one embodiment of the present invention, the liquid cooling plate 2 is provided with N×M slots, and the bottom of each battery cell 13 is inserted into the corresponding slot. In this embodiment, preferably, N is 2, and the two battery modules are parallel to each other.

[0025] In one embodiment of the present invention, the fixing device is an annular steel belt 15, and the steel belt 15 is tied to the periphery of each battery cell 13. The steel belt 15 is tied to the periphery of each battery cell 13. The steel belt 10 is used to fix each battery cell 13, which has a simple structure and is easy to install.

[0026] In one embodiment of the present invention, each battery module is attached with end plates 14 at both ends. Providing the end plates 14 at the outermost sides of the front and rear ends of the battery module can not only improve the overall rigidity of the entire battery module, but also prevent the steel belt 15 from damaging the battery cells 13 at the outer ends when fixing each battery cell 13, further improving the reliability of use.

[0027] As attached Figure 5 As shown, in one embodiment of the present invention, the above-mentioned heat-conducting layer is made of an inverse opal structure material. When the battery module is working, the temperature of the front surface, the rear surface and the topological fins 11 of the battery cell 13 is relatively high, and the coolant here will make the boiling phenomenon more intense. During the boiling process of the coolant, the porous capillary core of the inverse opal structure material is used to pull the coolant to the boiling surface through capillary force, and the coolant added to the boiling surface drives the bubbles to escape from the inverse opal structure material in a vertical direction, thereby taking away a large amount of heat, effectively reducing the temperature of the battery module during operation, and forming a benign gas-liquid two-phase cycle. Thereby, the critical heat flux density of the boiling surface is increased, and the comprehensive heat transfer coefficient of the coolant two-phase flow sweeping the battery surface is increased. At the same time, the combination of the inverse opal structure and the topological fins enhances the mixing characteristics of the gas-liquid two-phase fluid on the battery surface, thereby enhancing the uniformity of the coolant flow field and temperature field distribution near the battery surface, and ultimately improving the flow and heat transfer characteristics of the battery module.

[0028] In one embodiment of the present invention, the cooling liquid supply system I includes a cooling plate inlet 5 disposed at the left end of the cooling plate 2 and a cooling plate outlet 6 disposed at the right end. The cooling plate inlet 5 and the cooling plate outlet 6 are both connected to the cooling chamber I. The cooling plate inlet 5 is connected to the outlet end of the cooling liquid pump, and the cooling plate outlet 6 is connected to the inlet end of the cooling liquid pump. The cooling liquid pump delivers the cooling liquid into the cooling chamber I through the cooling plate inlet 5 to fully exchange heat with the condensation end 10 of each loop heat pipe. After the heat exchange, the cooling liquid flows back to the cooling liquid pump through the cooling plate outlet 6 to realize circulation.

[0029] In one embodiment of the present invention, the coolant supply system II includes a liquid inlet 3 disposed at the front end of the liquid cooling box 1 and a liquid outlet 4 disposed at the rear end of the liquid cooling box 1. The axis of the liquid inlet 3 and the axis of the liquid outlet 4 are perpendicular to the surface of the battery cell 13. The liquid inlet 3 is connected to the outlet end of the coolant pump, and the liquid outlet 4 is connected to the inlet end of the coolant pump. The coolant pump delivers the coolant into the liquid cooling chamber II of the liquid cooling box 1 through the liquid inlet 3. Since the axis of the liquid inlet 3 is perpendicular to the surface of the battery cell 13, the coolant will impact the surface of the battery cell 13 and fully exchange heat with the battery cell 13. After the heat exchange, the coolant flows back to the coolant pump through the liquid outlet 4 to achieve circulation.

[0030] In one embodiment of the present invention, the number and shape of the topological fins 11 are obtained by topologically optimizing the battery surface ribs using COMSOL software with the highest comprehensive heat transfer coefficient in the heat transfer process of the cooling liquid sweeping over the surface of the battery cell 13 and with the minimum pressure drop as the optimization goal. Fig. 9 As shown in the figure, by comparing with the circular staggered battery surface structure and the square staggered battery surface structure, it is found that the average surface temperature of the battery cell 13 of the present invention decreases with the increase of the initial velocity of the fluid, and the surface temperature of the battery with the topological fins 11 is always lower than that of the circular staggered battery surface structure and the square staggered battery surface structure, indicating that the heat dissipation performance of the topological fin 11 structure is better than that of the traditional structure. Fig.10 As shown, the average surface temperature of the three batteries decreases with the increase of pump work, and when the same temperature is reached, the structure of the topological fin 11 of the present invention consumes less pump work than the other two structures, indicating that the structure of the topological fin 11 is superior to the traditional structure in terms of energy consumption.

[0031] As attached Figure 8 As shown, in one embodiment of the present invention, a plurality of blocking sheets 16 are arranged at intervals along the axial direction on the left and right sides of the liquid channel 8 of the loop heat pipe, and the blocking sheets 16 are triangular structures, and the blocking sheets 16 located on the left side of the liquid channel 8 and the blocking sheets 16 located on the right side of the liquid channel 8 are symmetrically arranged in an eight-shaped shape. The blocking sheets 16 are arranged on the left and right sides of the liquid channel 8 to form a bionic fleshy capillary structure in design. The bionic fleshy capillary structure, based on its fluid directional transport advantage, arranges a unique asymmetric return structure of fleshy flesh on the wall of the liquid channel 8, thereby causing the liquid curved liquid surface to have differences in two opposite directions, and cooperates with the capillary force to make the liquid flow in a directional direction in the anti-gravity direction. The blocking sheets 16 at the left and right ends are arranged in an eight-shaped shape, and the angle between the upper end of the blocking sheet 16 and the inner wall of the liquid channel 8 is 57°, and the angle between the lower end and the inner wall of the liquid channel 8 is 51°. This asymmetry causes the refrigerant to twist in two directions, realizing the directional transport of the liquid refrigerant in the anti-gravity direction, and providing power for the refrigerant flow.

[0032] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An immersion type liquid cooling energy storage power station thermal management system combining an inverse opal structure surface and a bionic heat pipe, characterized in that: include: A liquid cooling plate (2) has a sealed liquid cooling chamber I inside, and a liquid cooling box (1) is buckled on the upper end thereof, so that the liquid cooling box (1) and the liquid cooling plate (2) form a sealed liquid cooling chamber II; N battery modules are fixed on a liquid cooling plate (2), each battery module being composed of M battery cells (13) fixed by a fixing device; The front surface and the rear surface of each two battery cells (13) are respectively provided with P outwardly protruding topological fins (11); the front surface and the rear surface of the battery cells (13) and the surface of each topological fin (11) are provided with a heat conducting layer (12); the outer end of each heat conducting layer (12) is in contact with the evaporation end (7) of the loop heat pipe; The condensing end (10) of each loop heat pipe is embedded in the liquid cooling chamber I of the liquid cooling plate (2); one end of the condensing end (10) is connected to one end of the corresponding evaporating end (7) through a steam channel (9), and the other end of the condensing end (10) is connected to the other end of the corresponding evaporating end (7) through a liquid channel (8); A coolant supply system I, arranged on the liquid cooling plate (2) and used for supplying coolant into the liquid cooling chamber I; as well as The cooling liquid supply system II is arranged on the liquid cooling box (1) and is used to supply the cooling liquid into the liquid cooling chamber II.

2. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1 is characterized in that: The liquid cooling plate (2) is provided with N×M card slots, and the bottom of each battery cell (13) is inserted into a corresponding card slot.

3. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1 is characterized in that: The value of N is 2, and the two battery modules are parallel to each other.

4. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1, characterized in that: The fixing device is an annular steel belt (15), and the steel belt (15) is bundled around the periphery of each battery cell (13).

5. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 4 is characterized in that: End plates (14) are respectively attached to the left and right ends of each battery module.

6. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1 is characterized in that: The heat conducting layer is made of an inverse opal structure material.

7. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1 is characterized in that: The cooling liquid supply system I comprises a cooling plate inlet (5) arranged at the left end of the cooling plate (2) and a cooling plate outlet (6) arranged at the right end. The cooling plate inlet (5) and the cooling plate outlet (6) are both connected to the cooling chamber I. The cooling plate inlet (5) is connected to the outlet end of the cooling liquid pump, and the cooling plate outlet (6) is connected to the inlet end of the cooling liquid pump.

8. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1 is characterized in that: The coolant supply system II comprises a liquid inlet (3) arranged at the front end of the liquid cooling box (1) and a liquid outlet (4) arranged at the rear end of the liquid cooling box (1). The axis of the liquid inlet (3) and the axis of the liquid outlet (4) are perpendicular to the surface of the battery cell (13). The liquid inlet (3) is connected to the outlet end of the coolant pump, and the liquid outlet (4) is connected to the inlet end of the coolant pump.

9. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1, characterized in that: The number and shape of the topological fins (11) are obtained by topologically optimizing the battery surface ribs using COMSOL software, with the highest comprehensive heat transfer coefficient in the heat transfer process of the cooling liquid sweeping the surface of the battery cell (13) and with the minimum pressure drop as the optimization goal.

10. The immersion type liquid cooling energy storage power station thermal management system combining the inverse opal structure surface and the bionic heat pipe according to claim 1, characterized in that: A plurality of blocking sheets (16) are arranged at intervals along the axial direction on the left and right sides of the liquid channel (8) of the loop heat pipe, the blocking sheets (16) being of a triangular structure, and the blocking sheets (16) located on the left side of the liquid channel (8) and the blocking sheets (16) located on the right side of the liquid channel (8) being symmetrically arranged in an eight-shaped shape.

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