Bionic structure loop heat pipe cooling system suitable for immersed liquid cooling energy storage power station

Abstract

A bionic structure loop heat pipe cooling system suitable for an immersed liquid-cooled energy storage power station relates to the field of immersed liquid-cooled battery thermal management, cooling liquid enters a liquid-cooled cavity of a liquid-cooled box body through a cooling circulation system, and the cooling liquid flows through the surface of a single battery to perform convective heat exchange. Meanwhile, after the evaporation end of the loop heat pipe absorbs the heat of the single batteries, the refrigerant in the loop heat pipe is changed into gas from liquid and then conveyed to the condensation end through the steam channel, the condensation end is cooled by the phase change filling layer, and the refrigerant is changed into liquid from gas and then flows back to the evaporation end through the working liquid channel, so that circulation is realized. Meanwhile, the plurality of fins are adhered to the surfaces of the battery monomers, and the phase change medium in the fins can absorb part of heat of the battery monomers, so that the heat dissipation capability of the whole cooling system is improved, and when the efficiency of the loop heat pipe and the cooling liquid is relatively low, the phase change medium can still work normally and absorb heat timely and effectively.

Description

Technical Field

[0001] The present invention relates to the field of thermal management of immersed liquid-cooled batteries, and in particular to a bionic structure loop heat pipe cooling system suitable for an immersed liquid-cooled energy storage power station. Background Art

[0002] The low-carbon transformation of the energy sector and the construction of a new power system have become urgent tasks. Given the inherent intermittent and volatile characteristics of new energy power generation methods such as wind power and solar power, they inevitably bring challenges to system stability in actual power grid operation. To meet this challenge, battery energy storage technology, as an indispensable flexible adjustment resource in new power systems, is becoming increasingly important. With its excellent two-way rapid adjustment capabilities, this technology can accurately balance electricity supply and demand on different time scales, effectively support large-scale new energy grid connection, and thus significantly alleviate the supply and demand imbalance faced by local power grids. Today, countries around the world are actively promoting the development of battery energy storage.

[0003] However, while battery energy storage technology is developing rapidly, safety accidents in energy storage power stations around the world are emerging one after another, resulting in huge economic losses. Energy storage batteries will continue to heat up during operation, and heat will accumulate inside the battery, posing certain safety hazards of thermal runaway. In order to prevent thermal runaway and ensure the safe operation of the energy storage system, an effective battery cooling system is necessary. At present, the cooling technology of energy storage batteries is mainly air cooling and liquid cooling. Air cooling technology usually uses a fan to drive air and battery modules for convection heat exchange, but due to the low heat transfer coefficient of air, air cooling technology has limited heat dissipation efficiency, slow cooling speed, and long cooling time. Compared with air, liquid has higher specific heat capacity and thermal conductivity, and liquid cooling heat dissipation efficiency is usually higher. Therefore, in large-scale engineering applications, liquid cooling technology is more conducive to improving the working performance of energy storage systems. Battery immersion liquid cooling technology is a heat dissipation technology that directly immerses the battery in coolant. It makes full use of the high thermal conductivity of the coolant to absorb the heat generated by the battery, thereby ensuring that the battery operates within a suitable temperature range.

[0004] The loop heat pipe is an efficient cooling device that drives the working fluid to flow through the capillary force generated by the liquid wick in the heat pipe, and uses the phase change process of the working fluid to efficiently transfer heat. The loop heat pipe is generally composed of an evaporation end, a condensation end, a steam pipeline, and a liquid pipeline. By utilizing the phase change heat absorption mechanism of the working fluid, the loop heat pipe can quickly transfer heat from the heat source to the heat dissipation area, effectively improving the heat dissipation performance. And the loop heat pipe can maintain a good thermal balance during operation to ensure stable and reliable operation of the system. The battery module of the energy storage power station not only has the characteristics of high power density, but also easily generates a lot of heat, and has high requirements for temperature uniformity. However, the independent operation of immersion liquid cooling cannot meet the high requirements for heat dissipation of the battery module, and consumes a lot of energy. Therefore, it is necessary to design a cooling system with multiple heat dissipation methods to cooperate in heat dissipation. Summary of the invention

[0005] In order to overcome the deficiencies of the above technologies, the present invention provides a bionic structure loop heat pipe cooling system for an immersion liquid-cooled energy storage power station, which improves the heat dissipation capacity of the entire cooling system and enhances the heat dissipation rate.

[0006] The technical solution adopted by the present invention to overcome the technical problems is: A bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station, comprising: A liquid cooling box body, wherein a sealed liquid cooling chamber is provided inside; N rows of battery packs are located in the liquid cooling chamber, each row of battery packs is composed of M battery cells arranged at intervals along the front-to-back direction, and each battery cell is fixed on the bottom plate of the liquid cooling box; A cooling circulation system is provided on the liquid cooling box body and is used to drive the coolant to circulate in the liquid cooling cavity; N×M loop heat pipes, the evaporation end of each loop heat pipe is attached to the surface of the corresponding battery cell, the evaporation end of the loop heat pipe is bent to form a continuous bent portion of a "X" structure, each bent portion is embedded with a rib, the rib is attached and fixed to the surface of the corresponding battery cell, the rib is filled with a phase change medium, the condensation end of the loop heat pipe is located above the liquid cooling box, one end of the evaporation end of the loop heat pipe is connected to one end of the condensation end through a working liquid channel, and the other end of the evaporation end of the loop heat pipe is connected to the other end of the condensation end through a steam channel; and The phase change filling layer is arranged above the liquid cooling box, and the phase change filling layer wraps and fixes each condensation end.

[0007] Furthermore, the bottom plate is provided with N×M slots, and the bottom of each battery cell is inserted into the corresponding slot.

[0008] Preferably, the value of N is 2, and the two rows of battery packs are parallel to each other.

[0009] Furthermore, the above-mentioned cooling circulation system includes a liquid inlet arranged at the front end of the liquid cooling box body and a liquid outlet arranged at the rear end of the liquid cooling box body. 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.

[0010] Preferably, the condensing end of the loop heat pipe is bent to form a continuous "X"-shaped structure.

[0011] Preferably, the phase change medium is a mixture of graphene and paraffin.

[0012] Preferably, the phase change filling layer is made of a mixture of graphene and paraffin.

[0013] 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 working fluid channel of the loop heat pipe. The blocking plates are of a triangular structure, and the blocking plates located on the left side of the working fluid channel and the blocking plates located on the right side of the working fluid channel are symmetrically arranged.

[0014] Preferably, the angle between the upper end of the blocking sheet and the inner wall of the working fluid channel is , , the angle between the lower end of the blocking piece and the inner wall of the working fluid channel is , .

[0015] In order to improve the heat exchange capacity, it also includes a number of guide plates arranged on the bottom plate at intervals along the front-to-back direction and located at the left end of the battery cell, and a number of guide plates arranged on the bottom plate at intervals along the front-to-back direction and located at the right end of the battery cell. The guide plate on the left and the corresponding guide plate on the right are arranged in an eight-shaped shape with each other.

[0016] The beneficial effects of the present invention are as follows: a plurality of strip-shaped fins are arranged on the surface of each battery cell of the present invention, and a phase change medium is sealed inside the fins, which not only increases the heat dissipation area of ​​the battery cell, strengthens the heat transfer between the battery cell and the coolant and between the battery and the loop heat pipe, but also the phase change cutoff can absorb part of the heat of the battery cell, thereby improving the heat dissipation capacity of the entire cooling system. When the cooling efficiency of the loop heat pipe and the coolant is low, the phase change medium in the fins can still work normally, and absorb the heat of the battery cell in a timely and effective manner.

[0017] The present invention adds a bionic loop heat pipe on the basis of immersion liquid cooling. The immersion liquid cooling and the loop heat pipe are coupled to dissipate heat, thereby improving the heat dissipation efficiency of the battery. At the same time, the coolant flow rate can be actively reduced to reduce the pump power loss of the immersion liquid cooling. Both the evaporation end and the condensation end of the loop heat pipe are provided with continuous bending parts, which are arranged on the surface of the battery cell and in the phase change filling layer respectively, thereby increasing the heat exchange area and enhancing the heat dissipation rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional structural diagram of the present invention; Figure 2 A three-dimensional structural diagram of a battery module of the present invention; Figure 3 It is a schematic diagram of the main structure of the loop heat pipe of the present invention; Figure 4 is a cross-sectional structural diagram of the working fluid channel of the present invention; Figure 5 It is a top view of the structure of the liquid cooling box of the present invention; Figure 6 It is a cross-sectional structural diagram of the fin part of the present invention; In the figure, 1. liquid cooling box 2. battery cell 3. liquid inlet 4. liquid outlet 5. condensation end 6. phase change filling layer 7. bottom plate 8. evaporation end 9. fins 10. guide plate 11. working liquid channel 12. steam channel 13. barrier sheet 14. phase change medium. DETAILED DESCRIPTION

[0019] The following is combined with Figure 1 To Attachment Figure 6 The present invention is further described.

[0020] A bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station, comprising: a liquid-cooling box 1, which is provided with a closed liquid-cooling cavity; N rows of battery packs, located in the liquid-cooling cavity, each row of battery packs is formed by M battery cells 2 arranged at intervals in the front-to-back direction, and each battery cell 2 is fixed on a bottom plate 7 of the liquid-cooling box 1; a cooling circulation system, which is arranged on the liquid-cooling box 1 and is used to drive the coolant to circulate in the liquid-cooling cavity; N×M loop heat pipes, each loop heat pipe has an evaporation end 8 attached to the surface of the corresponding battery cell 2, and the loop heat pipe has an evaporation end 8 attached to the surface of the corresponding battery cell 2. The evaporation end 8 is bent to form a continuous bending part of a "X"-shaped structure, each bending part is embedded with a fin 9, the fin 9 is fixed to the surface of the corresponding battery cell 2, and the fin is filled with a phase change medium 14. The condensation end 5 of the loop heat pipe is located above the liquid cooling box 1, one end of the evaporation end 8 of the loop heat pipe is connected to one end of the condensation end 5 through the working liquid channel 11, and the other end is connected to the other end of the condensation end 5 through the steam channel 12; and the phase change filling layer 6 is arranged above the liquid cooling box 1, and the phase change filling layer wraps and fixes each condensation end 5. The coolant enters the liquid cooling cavity of the liquid cooling box 1 through the cooling circulation system, and the coolant flows through the surface of the battery cell 2 for convection heat exchange. At the same time, after the evaporation end 8 of the loop heat pipe absorbs the heat of the battery cell 2, the refrigerant in the loop heat pipe changes from liquid to gas and is transported to the condensation end 5 through the steam channel 12. The condensation end 5 is cooled by the phase change filling layer, and the refrigerant changes from gas to liquid and flows back to the evaporation end 8 through the working liquid channel 11 to achieve circulation. At the same time, multiple fins 9 are adhered to the surface of the battery cell 2. The phase change medium 14 in the fins 9 can absorb part of the heat of the battery cell 2, thereby improving the heat dissipation capacity of the entire cooling system. When the efficiency of the loop heat pipe and the coolant is low, the phase change medium 14 can still work normally and absorb heat in a timely and effective manner.

[0021] In one embodiment of the present invention, N×M slots are provided on the bottom plate 7, and the bottom of each battery cell 2 is inserted into the corresponding slot. In this embodiment, preferably, N is 2, and the two rows of battery packs are parallel to each other.

[0022] In one embodiment of the present invention, the cooling circulation system may be of the following structure, which 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, wherein the axis of the liquid inlet 3 and the axis of the liquid outlet 4 are perpendicular to the surface of the battery cell 2, 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 cavity 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 2, the coolant will impact the surface of the battery cell 2 and fully exchange heat with the battery cell 2. After the heat exchange, the coolant flows back to the coolant pump through the liquid outlet 4 to achieve circulation.

[0023] In one embodiment of the present invention, the condensation end 5 of the loop heat pipe is bent to form a continuous "X"-shaped structure. The condensation end 5 can increase the heat exchange area between the refrigerant and the phase change filling layer 6 in the loop heat pipe through the continuous bending structure, thereby improving the heat exchange efficiency.

[0024] In one embodiment of the present invention, preferably, the phase change medium 14 is a mixture of graphene and paraffin. The phase change filling layer 6 is made of a mixture of graphene and paraffin.

[0025] Several blocking sheets 13 are arranged at intervals along the axial direction on the left and right sides of the working fluid channel 11 of the loop heat pipe, and the blocking sheets 13 are triangular structures, and the blocking sheets 13 on the left side of the working fluid channel 11 and the blocking sheets 13 on the right side of the working fluid channel 11 are symmetrically arranged. The blocking sheets 13 on the left and right sides of the working fluid channel 11 form a bionic fleshy capillary structure in design, which has the function of directional transport of refrigerant and provides power for the flow of refrigerant.

[0026] In one embodiment of the present invention, preferably, the angle between the upper end of the blocking sheet 13 and the inner wall of the working fluid channel 11 is , The angle between the lower end of the blocking piece 13 and the inner wall of the working fluid channel 11 is , The barrier sheet 13 is an asymmetric structure. Therefore, the asymmetry of the barrier sheet 13 is used to make the refrigerant spread unevenly in two directions when flowing through the working fluid channel 11, affecting the conveying direction of the refrigerant. The refrigerant flows in the direction of the condensation end 5 and diffuses to the next adjacent barrier sheet 13. In the same way, the refrigerant is spontaneously and continuously transported along the specific single direction to achieve directional transmission of the refrigerant, and the refrigerant is guided from the condensation end 5 to the evaporation end 8 to complete the heat exchange cycle.

[0027] In one embodiment of the present invention, it also includes a plurality of guide plates 10 arranged on the bottom plate 7 at intervals along the front-to-back direction and located at the left end of the battery cell 2, and a plurality of guide plates 10 arranged on the bottom plate 7 at intervals along the front-to-back direction and located at the right end of the battery cell 2, and the guide plates 10 on the left and the corresponding guide plates 10 on the right are arranged in an eight-shaped shape. When the coolant enters the liquid cooling cavity of the liquid cooling box 1, each guide plate 10 actively guides the coolant, so that the coolant impacts the surface of the battery cell 2, and then flows through each battery cell 2 for convective heat exchange, further improving the heat exchange efficiency.

[0028] 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. A bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station, characterized in that: include: A liquid cooling box (1) having a sealed liquid cooling chamber therein; N rows of battery packs are located in the liquid cooling chamber, each row of battery packs is composed of M battery cells (2) arranged at intervals along the front-to-back direction, and each battery cell (2) is fixed on a bottom plate (7) of the liquid cooling box (1); A cooling circulation system, arranged on the liquid cooling box (1) and used for driving the cooling liquid to circulate in the liquid cooling chamber; N×M loop heat pipes, the evaporation end (8) of each loop heat pipe being adhered to the surface of the corresponding battery cell (2), the evaporation end (8) of the loop heat pipe being bent to form a continuous bent portion in a "J" shape, each bent portion being embedded with a rib (9), the rib (9) being adhered and fixed to the surface of the corresponding battery cell (2), the rib being filled with a phase change medium (14), the condensation end (5) of the loop heat pipe being located above the liquid cooling box (1), one end of the evaporation end (8) of the loop heat pipe being connected to one end of the condensation end (5) via a working fluid channel (11), and the other end of the evaporation end (8) of the loop heat pipe being connected to the other end of the condensation end (5) via a steam channel (12); and The phase change filling layer (6) is arranged above the liquid cooling box (1), and the phase change filling layer wraps and fixes each condensation end (5).

2. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1 is characterized in that: The bottom plate (7) is provided with N×M card slots, and the bottom of each battery cell (2) is inserted into a corresponding card slot.

3. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1 is characterized in that: The value of N is 2, and the two rows of battery packs are parallel to each other.

4. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1 is characterized in that: The cooling circulation system 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 (2); the liquid inlet (3) is connected to the outlet end of the cooling liquid pump, and the liquid outlet (4) is connected to the inlet end of the cooling liquid pump.

5. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1 is characterized in that: The condensation end (5) of the loop heat pipe is bent to form a continuous "X"-shaped structure.

6. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1 is characterized in that: The phase change medium (14) is a mixture of graphene and paraffin.

7. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1 is characterized in that: The phase change filling layer (6) is made of a mixture of graphene and paraffin.

8. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1 is characterized in that: A plurality of blocking sheets (13) are arranged at intervals along the axial direction on the left and right sides of the working fluid channel (11) of the loop heat pipe, the blocking sheets (13) being of a triangular structure, and the blocking sheets (13) located on the left side of the working fluid channel (11) and the blocking sheets (13) located on the right side of the working fluid channel (11) being arranged symmetrically with each other.

9. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 8, characterized in that: The angle between the upper end of the blocking plate (13) and the inner wall of the working fluid channel (11) is , The angle between the lower end of the blocking plate (13) and the inner wall of the working fluid channel (11) is , .

10. The bionic structure loop heat pipe cooling system suitable for an immersion liquid-cooled energy storage power station according to claim 1, characterized in that: It also comprises a plurality of guide plates (10) arranged at intervals on the bottom plate (7) along the front-to-back direction and located at the left end of the battery cell (2), and a plurality of guide plates (10) arranged at intervals on the bottom plate (7) along the front-to-back direction and located at the right end of the battery cell (2), wherein the guide plate (10) on the left and the corresponding guide plate (10) on the right are arranged in an eight-shaped pattern.

Images