Two-phase immersion liquid-cooled battery pack

Abstract

The present application discloses a two-phase immersion liquid-cooled battery pack. The two-phase immersion liquid-cooled battery pack comprises a housing, multiple battery cells, and multiple buffer assemblies. The housing is provided with a cavity, the cavity being configured to be filled with an immersion liquid. The multiple battery cells are disposed at intervals within the cavity. The multiple buffer assemblies are disposed between the battery cells. Each buffer assembly comprises a buffer member and a spacer member; the buffer member is connected to a side surface of a battery cell, and the spacer member is disposed on a side of the buffer member away from the battery cell, so as to form a channel between buffer members, the channel being configured to accommodate the immersion liquid.

Description

A dual-phase immersion liquid-cooled battery pack

[0001] This application claims priority to Chinese Patent Application No. 2024117089270, filed with the Chinese Patent Office on November 26, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the technical field of batteries, and in particular to a two-phase immersion liquid-cooled battery pack. Background Technology

[0003] Currently, most lithium battery-based liquid cooling systems use indirect liquid cooling technology, while there is relatively little research on immersion liquid cooling technology. Technical issues

[0004] In immersion liquid cooling systems, the materials and shapes used between the cells are consistent with those in indirect liquid cooling systems, with two strips of foam material placed between them. This results in uneven distribution of the immersion liquid between the cells, affecting their heat dissipation performance. Technical solutions

[0005] In a first aspect, this application provides a dual-phase immersion liquid-cooled battery pack, which includes a housing, multiple individual cells, and multiple buffer components. The housing has a cavity for filling with immersion liquid. The multiple individual cells are spaced apart in the cavity. The multiple buffer components are disposed between the individual cells. Each buffer component includes a buffer member and a spacer member. The buffer member is connected to the side of the individual cell, and the spacer member is disposed on the side of the buffer member away from the individual cell to form a channel between the buffer members. The channel is configured to accommodate the immersion liquid. Beneficial effects

[0006] The beneficial effects provided by this application are as follows: individual cells and buffer components are arranged alternately in sequence. The buffer components are provided with buffer parts that are connected to the side of the individual cells, thereby achieving a buffering effect. Spacers are arranged between the buffer parts to form channels between the buffer parts. Immersion liquid can be contained in the channels, thereby filling the spaces between the individual cells, making the distribution of immersion liquid more uniform, absorbing the heat generated by the individual cells, improving the heat dissipation effect, and reducing the temperature of the individual cells. Attached Figure Description

[0007] Figure 1 is a schematic diagram of the structure of the dual-phase immersion liquid-cooled battery pack provided in an embodiment of this application;

[0008] Figure 2 is a cross-sectional schematic diagram of a single battery cell and a buffer assembly provided in an embodiment of this application.

[0009] Figure 3 is a partially enlarged schematic diagram of region A in Figure 2 provided in an embodiment of this application;

[0010] Figure 4 is a schematic diagram of the structure of a single battery cell and a buffer assembly combined together according to an embodiment of this application;

[0011] Figure 5 is a structural schematic diagram of the spacer in Figure 4 provided in an embodiment of this application;

[0012] Figure 6 is a schematic diagram of the structure of a single battery cell and a buffer assembly combined together according to an embodiment of this application;

[0013] Figure 7 is a structural schematic diagram of the spacer in Figure 6 provided in an embodiment of this application;

[0014] Figure 8 is a cross-sectional schematic diagram of a single battery cell and a buffer assembly provided in an embodiment of this application.

[0015] Figure 9 is a partially enlarged schematic diagram of region B in Figure 8 provided in an embodiment of this application.

[0016] Explanation of reference numerals in the attached figures:

[0017] Box body 20, first end 21, second end 23, first liquid inlet 25, first liquid outlet 27;

[0018] Individual cell 30, buffer assembly 10, buffer component 12, through hole 122, spacer 14, through groove 142; micro hole 144, liquid cooling plate 40, third end 41, fourth end 43, second liquid inlet 45;

[0019] Second liquid outlet 47.

[0020] Implementation methods of this application

[0021] Referring to Figures 1 to 3, Figure 1 is a structural schematic diagram of a dual-phase immersion liquid-cooled battery pack provided in an embodiment of this application, Figure 2 is a cross-sectional schematic diagram of a single cell 30 and a buffer assembly 10 combined together in an embodiment of this application, and Figure 3 is a partially enlarged schematic diagram of region A in Figure 2 provided in an embodiment of this application.

[0022] This application provides a dual-phase immersion liquid-cooled battery pack, comprising: a housing 20, multiple individual cells 30, and multiple buffer components 10. The housing 20 has a cavity filled with an immersion liquid, which can be a fluorinated liquid, silicone liquid, etc., and has both thermal conductivity and insulating properties. The individual cells 30 can store electrical energy and can be lithium batteries, sodium batteries, rechargeable batteries, etc. Multiple individual cells 30 are spaced apart within the cavity, and each individual cell 30 generates heat during operation.

[0023] Multiple buffer components 10 are disposed between individual cells 30. The buffer components 10 are elastic, thus providing a cushioning and shock-absorbing effect. Each buffer component 10 includes a buffer member 12 and a spacer 14. The buffer member 12 is connected to the side of the individual cell 30. When the individual cells 30 are arranged along the thickness direction, the buffer member 12 is connected to the largest side of the individual cell 30; when the individual cells 30 are arranged along the width direction, the buffer member 12 is connected to the smallest side of the individual cell 30. The spacer 14 is disposed on the side of the buffer member 12 away from the individual cell 30 to form a channel between the buffer members 12. This channel is configured to accommodate immersion liquid. Buffer members 12 are disposed on opposite sides of the spacer 14.

[0024] The spacer 14 is located on the side of the buffer 12 away from the single cell 30, including at least two cases: a) spacers 14 are provided on both adjacent buffers 12, and the spacers 14 can be opposite to each other or staggered; b) on adjacent buffers 12, one buffer 12 is provided with a spacer 14, and the other buffer 12 is not provided with a spacer 14, the spacer 14 connects to the other buffer 12, and there can be a gap between the spacer 14 and the other buffer.

[0025] During operation, the immersion fluid continuously exchanges with the external immersion fluid, carrying away the heat from the individual cells 30. The immersion fluid remaining in the channel absorbs the heat from the individual cells 30. As the immersion fluid flows, it carries away the immersion fluid in the channel, thereby also carrying away the heat from the channel.

[0026] In this application, the individual battery 30 and the buffer assembly 10 are arranged alternately in sequence. The buffer assembly 10 is provided with a buffer element 12 connected to the side of the individual battery 30, thereby playing a buffering role. The spacer 14 is arranged between the buffer elements 12, forming a channel between the buffer elements 12. The immersion liquid can be contained in the channel, thereby filling the space between the individual batteries 30, making the distribution of the immersion liquid more uniform, absorbing the heat generated by the individual battery 30, improving the heat dissipation effect, and reducing the temperature of the individual battery 30.

[0027] Therefore, this application increases the heat exchange area between the immersion liquid and the individual cell 30, so that each side of the individual cell 30 can be wrapped by the immersion liquid, thereby improving the heat absorption effect of the immersion liquid on the individual cell 30 and achieving the effect of uniform temperature of the individual cell 30.

[0028] The cushioning element 12 can be made of foam, silicone, or other materials. The spacer 14 can be made of copper or aluminum.

[0029] In an optional embodiment, the thickness of the buffer assembly 10 is D, where 0.5 mm ≤ D ≤ 5 mm. Here, D is the thickness of the buffer assembly 10 before compression or deformation. This thickness can also indirectly represent the thickness between the individual battery cells 30. D can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc. With the thickness of the buffer assembly 10 within this range, the buffer member 12 can have a sufficiently large deformation space. In addition, there is space for the spacer member 14 to be placed to form a channel for the flow of immersion liquid.

[0030] When the thickness of the buffer assembly 10 is less than this range, the buffer element 12 and the spacer 14 cannot be properly positioned to form a channel for the immersion liquid to flow. When the thickness of the buffer assembly 10 is greater than this range, the buffer element 12 and the spacer 14 occupy too much space, thus encroaching on the space of the individual battery cell 30, thereby reducing the energy density of the two-phase immersion liquid-cooled battery pack.

[0031] Referring to Figures 4 and 5, Figure 4 is a structural schematic diagram of a single battery 30 and a buffer assembly 10 provided in an embodiment of this application, and Figure 5 is a structural schematic diagram of the spacer 14 in Figure 4 provided in an embodiment of this application.

[0032] In one optional embodiment, there are multiple spacers 14, which are spaced apart to form channels. The spacers 14 are independent of each other, and channels are formed between adjacent spacers 14. Therefore, the circumference of each spacer 14 is empty, providing ample space to form channels, increasing the channel capacity, holding more immersion liquid, and allowing the immersion liquid to fully contact the spacers 14 for heat absorption. Furthermore, the multiple spacers distributed among the buffer members 12 provide better support for each part of the buffer member 12, maintaining its normal shape.

[0033] The spacer 14 can be cylindrical, with its top and bottom surfaces being circular and connected to the buffer 12 respectively. The cylindrical circumference is a curved surface with a rounded transition, which can reduce the resistance to the immersion liquid when in contact with it, thereby improving the flow efficiency of the immersion liquid.

[0034] As shown in Figures 6 and 7, the spacer 14 can also be hemispherical. In this case, one side of the spacer 14 is a plane that contacts a buffer 12, and the other side of the spacer 14 is a spherical surface that makes point contact with a buffer 12. The hemispherical spacer 14 uses the spherical surface as its circumferential surface to contact the immersion liquid. Compared with a cylindrical shape, this reduces the resistance to the immersion liquid when in contact with it, thereby improving the flow efficiency of the immersion liquid.

[0035] Of course, the spacer 14 can also be in different shapes such as square column, frustum, cone, pyramid, or irregular shape, which will not be listed here.

[0036] Multiple spacers 14 can be evenly arranged, meaning the spacing between adjacent spacers 14 is the same or approximately the same, and the spacing between adjacent spacers 14 is L, where 50 micrometers ≤ L ≤ 200 micrometers. The spacing L can be 50 millimeters, 60 millimeters, 70 millimeters, 80 millimeters, 90 millimeters, 100 millimeters, 110 millimeters, 120 millimeters, 130 millimeters, 140 millimeters, 150 millimeters, 160 millimeters, 170 millimeters, 180 millimeters, 190 millimeters, 200 millimeters, etc. Within this range, the spacers 14 can provide good support for the buffer 12, and there is also enough space to form a channel for the immersion liquid to flow.

[0037] When the spacing between the spacers 14 is less than this range, the channels formed between the spacers 14 are too small to allow the immersion liquid to flow properly. When the spacing between the spacers 14 is greater than this range, the spacers 14 are insufficient to provide adequate support for the buffer 12.

[0038] The arrangement density of multiple spacers 14 can also be changed according to the size of the deformation of the individual battery 30. For example, the number of spacers 14 can be increased in the position where the deformation of the individual battery 30 is relatively large, and the number of spacers 14 can be reduced in the position where the deformation of the individual battery 30 is relatively small.

[0039] Specifically, the number of spacers 14 per unit area gradually decreases from the center of the side of the single cell 30 to the edge of the side of the single cell 30. In simple terms, the arrangement of spacers 14 on the side of the single cell 30 gradually becomes sparser as it spreads outward from the center of the side. As a result, the spacers 14 provide the strongest support to the center of the single cell 30 and the weakest support to the edge of the single cell 30.

[0040] Referring to Figures 8 and 9, Figure 8 is a cross-sectional schematic diagram of the single cell 30 and the buffer assembly 10 provided in the embodiment of this application, and Figure 9 is a partially enlarged schematic diagram of region B in Figure 8 provided in the embodiment of this application.

[0041] The spacer 14 has multiple spaced and parallel through slots 142. For example, multiple spaced and parallel through slots 142 are formed on a copper block by etching. The through slots 142 can be along the length direction or along the width direction, and the through slots 142 pass through the opposite ends of the spacer 14. The multiple through slots 142 form a channel to allow the flow of immersion liquid.

[0042] In this embodiment, the spacer 14 is an integral unit, and the through groove 142 is provided on the spacer 14 to ensure the stability of the distance between the through grooves 142, thereby ensuring that the immersion liquid can flow stably.

[0043] Please refer to Figure 5 or Figure 7. Micropores 144 are provided on the spacer 14. The micropores 144 are in a state of penetrating the spacer 14, allowing the immersion liquid to pass through. The micropores 144 are designed to change the droplet size of the immersion liquid through tension. A smaller droplet size lowers the boiling temperature of the immersion liquid, i.e., lowers the phase transition temperature from liquid to gas. The immersion liquid undergoes a phase transition at a lower temperature, thereby changing the phase transition temperature and improving the heat dissipation effect. Taking fluorinated liquid as an example, as the droplet size changes from 110μm to 50μm, the phase transition temperature of the fluorinated liquid can decrease from 78℃ to 68℃. The phase transition process leads to a change in state, which absorbs a large amount of heat. The process of the droplet changing from liquid to gas utilizes the latent heat of phase transition to absorb the heat generated by the battery, thereby reducing the battery temperature.

[0044] Specifically, the diameter of the micropore 144 is R, where 200 nm ≤ R ≤ 500 nm. The diameter R can be 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 310 nm, 330 nm, 350 nm, 380 nm, 390 nm, 400 nm, 410 nm, 430 nm, 440 nm, 450 nm, 480 nm, or 500 nm. Within this range, the micropore 144 does not compromise the overall strength of the spacer 14 and can effectively alter the droplet size of the immersion liquid. When the diameter of the micropore 144 is larger than this range, the strength of the spacer 14 is significantly weakened, and it may break under pressure. When the diameter of the micropore 144 is smaller than this range, the micropore 144 cannot effectively alter the droplet size of the immersion liquid.

[0045] The micropores 144 have at least five diameter sizes, namely R, 0.414R, 0.225R, 0.177R, and 0.116R. The micropore 144 with diameter R is the largest, the micropore 144 with diameter 0.414R is the second largest, the micropore 144 with diameter 0.225R is the third largest, the micropore 144 with diameter 0.177R is the fourth largest, and the micropore 144 with diameter 0.116R is the fifth largest. By distributing these five sizes of micropores 144, the number of micropores 144 on the spacer 14 can be maximized without compromising the strength of the spacer 14, thereby maximizing the contact area between the immersion liquid and the spacer 14 and thus better changing the droplet size of the immersion liquid.

[0046] In an optional embodiment, the buffer 12 has a plurality of through holes 122 along its thickness direction. The through holes 122 can be arranged uniformly or non-uniformly, allowing the immersion liquid to directly contact the side of the single cell 30 through the through holes 122, thereby improving heat exchange efficiency.

[0047] In an optional embodiment, the housing 20 has a first end 21 and a second end 23 disposed opposite to each other. The first end 21 is provided with a first liquid inlet 25, and the second end 23 is provided with a first liquid outlet 27. When the immersion liquid is injected into the cavity of the housing 20 through the first liquid inlet 25, it is at a relatively low temperature. As the immersion liquid flows within the cavity, its temperature gradually increases due to direct contact with the individual battery cells 30, and then it is discharged from the first liquid outlet 27. In this embodiment, the immersion liquid inside the housing 20 is flowing, which can more effectively remove heat and improve the heat dissipation effect.

[0048] The liquid cooling plate 40 is adjacent to the housing 20 and indirectly contacts the individual battery 30. The liquid cooling plate 40 can be located on the side, top, or bottom of the housing 20. The liquid cooling plate 40 shown in the attached diagram is located on the bottom of the housing 20. The liquid cooling plate 40 contains coolant, which flows inside the liquid cooling plate 40 and absorbs and carries away the heat transferred from the individual battery 30 to the liquid cooling plate 40. The liquid cooling plate 40 also has a third end 41 and a fourth end 43 arranged opposite to each other. The third end 41 has a second outlet 47, and the fourth end 43 has a second inlet 45. The coolant enters the liquid cooling plate 40 through the second inlet 45. When the coolant enters the liquid cooling plate 40, it is at a relatively low temperature. As the coolant flows inside the liquid cooling plate 40, its temperature gradually rises because it absorbs the heat transferred from the individual battery 30 to the liquid cooling plate 40, and then it is discharged from the second outlet 47.

[0049] The first end 21 and the third end 41 are adjacent, and the second end 23 and the fourth end 43 are adjacent. Therefore, the first inlet 25 of the immersion fluid and the second outlet 47 of the coolant are relatively close, as are the first outlet 27 of the immersion fluid and the second inlet 45 of the coolant. Understandably, although the temperature of the immersion fluid at the first outlet 27 of the second end 23 is relatively high, which is not conducive to heat dissipation in the area near the second end 23 of the housing 20, the second inlet 45, which is close to it, injects coolant at a lower temperature, which can effectively help dissipate heat and cool the area near the second end 23.

[0050] Similarly, although the coolant temperature is relatively high at the second outlet 47 of the third end 41, which is not conducive to the third end 41 of the liquid cooling plate 40 absorbing heat from the adjacent first end 21 of the housing 20, the first inlet 25 nearby injects a lower-temperature immersion liquid, which can effectively help dissipate heat and cool the area near the first end 21. Therefore, for the individual battery 30 in the housing 20, whether at the first end 21 or the second end 23 of the housing 20, there is always a lower-temperature cooling medium that can effectively help cool the individual battery 30.

[0051] This embodiment, through careful arrangement of the relative positions of the first inlet 25 and the first outlet 27 of the immersion liquid and the second inlet 45 and the second outlet 47 of the coolant, enables the immersion liquid and coolant of the battery pack 10 to work synergistically. This ensures that the individual cells 30 are adequately cooled in different areas, ensuring a more uniform and effective distribution of the heat generated by the individual cells 30. This reduces temperature differences on the surface of the individual cells 30, avoids localized heat accumulation in the individual cells 30, and makes the temperature distribution of the entire individual cells 30 more uniform. This reduces the risk of performance degradation and shortened lifespan of the individual cells 30 caused by temperature differences.

Claims

1. A dual-phase immersion liquid-cooled battery pack, comprising: The housing has a cavity, which is configured to be filled with an immersion liquid; Multiple individual battery cells are spaced apart within the cavity; Multiple buffer components are disposed between the individual cells. Each buffer component includes a buffer member and a spacer member. The buffer member is connected to the side of the individual cell. The spacer member is disposed on the side of the buffer member away from the individual cell to form a channel between the buffer members. The channel is configured to accommodate immersion liquid.

2. The dual-phase immersion liquid-cooled battery pack according to claim 1, wherein, The thickness of the buffer component is D, where 0.5 mm ≤ D ≤ 5 mm.

3. The dual-phase immersion liquid-cooled battery pack according to claim 2, wherein, 2 mm ≤ D ≤ 4 mm.

4. The dual-phase immersion liquid-cooled battery pack according to claim 1, wherein, The number of spacers is multiple, and the multiple spacers are spaced apart from each other to form the channel.

5. The dual-phase immersion liquid-cooled battery pack according to claim 4, wherein, The spacer is at least one of the following shapes: cylindrical, hemispherical, square column, frustum, cone, and pyramid.

6. The dual-phase immersion liquid-cooled battery pack according to claim 4, wherein, The spacers are evenly arranged, and the distance between adjacent spacers is L, where 50 micrometers ≤ L ≤ 200 micrometers.

7. The dual-phase immersion liquid-cooled battery pack according to claim 6, wherein, 100 micrometers ≤ L ≤ 150 micrometers.

8. The dual-phase immersion liquid-cooled battery pack according to claim 4, wherein, The number of spacers per unit area gradually decreases from the center of the side of the single cell to the edge of the side of the single cell.

9. The dual-phase immersion liquid-cooled battery pack according to claim 1, wherein, The spacer has multiple spaced and parallel through slots.

10. The dual-phase immersion liquid-cooled battery pack according to claim 9, wherein, The through groove extends through the opposite ends of the spacer along its length or width.

11. The dual-phase immersion liquid-cooled battery pack according to any one of claims 1 to 10, wherein, The spacer has micropores.

12. The dual-phase immersion liquid-cooled battery pack according to claim 11, wherein, The diameter of the micropore is R, where 200 nm ≤ R ≤ 500 nm.

13. The dual-phase immersion liquid-cooled battery pack according to claim 12, wherein, 300 nm ≤ R ≤ 400 nm.

14. The dual-phase immersion liquid-cooled battery pack according to claim 11, wherein, The micropores have at least five diameter sizes, namely R, 0.414R, 0.225R, 0.177R, and 0.116R.

15. The dual-phase immersion liquid-cooled battery pack according to any one of claims 1 to 10, wherein, The buffer component has multiple through holes along its thickness direction.

16. The dual-phase immersion liquid-cooled battery pack according to any one of claims 1 to 10, wherein the buffer is made of foam or silicone.

17. The dual-phase immersion liquid-cooled battery pack according to any one of claims 1 to 10, wherein the spacer is made of aluminum or copper.

18. The dual-phase immersion liquid-cooled battery pack according to any one of claims 1 to 10, wherein, The housing includes a first end and a second end disposed opposite to each other, the first end being provided with a first liquid inlet and the second end being provided with a first liquid outlet; The dual-phase immersion liquid-cooled battery pack also includes a liquid cooling plate adjacent to the housing. The liquid cooling plate is configured to contain coolant. The liquid cooling plate includes a third end and a fourth end arranged opposite to each other. The third end is provided with a second liquid outlet, and the fourth end is provided with a second liquid inlet. The first end and the third end are adjacent to each other, and the second end and the fourth end are adjacent to each other.

19. The dual-phase immersion liquid-cooled battery pack according to any one of claims 1 to 10, wherein, Each of the adjacent buffer members is provided with a spacer, and the spacers are opposite to each other or staggered.

20. The dual-phase immersion liquid-cooled battery pack according to any one of claims 1 to 10, wherein, On adjacent buffers, one buffer is provided with a spacer, the spacer connecting the other buffer.

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