Liquid cooling plate, battery pack heat dissipation structure and battery pack

Abstract

The utility model provides a kind of liquid cooling plate, battery pack heat dissipation structure and battery pack, the liquid cooling plate includes including for directly contacting the upper cold plate of cell bottom and with the lower cold plate cooperation formation liquid cooling flow passage, the upper cold plate folding formation periodic arrangement several heat exchange sawtooth, the shape of the heat exchange sawtooth is inverted V shape towards straight trihedral prism, the battery pack heat dissipation structure includes cell and as described above liquid cooling plate, the heat exchange sawtooth is along the bottom length direction arrangement of the cell, the bottom of the cell is engaged with the heat exchange sawtooth.The utility model discloses liquid cooling plate, battery pack heat dissipation structure and battery pack, with the advantages that heat conduction efficiency is high and temperature field uniformity is good.

Description

Technical Field

[0001] This utility model belongs to the field of battery heat dissipation technology, specifically relating to a liquid cooling plate, a battery pack heat dissipation structure, and a battery pack. Background Technology

[0002] As new energy vehicles and energy storage systems develop towards high energy density (≥280Wh / kg) and fast charging capability (≥3C), the thermal management of square battery packs faces the following severe challenges: (1) Increased heat accumulation: The heat generation power of a single cell exceeds 1500W during high-power continuous discharge, and the heat flux density at the module level exceeds 5000W / m³; (2) Approaching safety critical point: When the cell temperature is >60℃, the decomposition rate of the SEI film increases exponentially, and a local temperature difference >5℃ will cause a drop in capacity; (3) System energy efficiency bottleneck: The power consumption of the cooling system accounts for nearly 20% of the total energy consumption, which seriously restricts the driving range.

[0003] Currently, most square battery packs employ a planar contact liquid cooling solution. The conventional placement of the cells involves placing insulating foam between the large surfaces of the cells, with positive and negative terminals leading out from the top of the cells and connected to leads for voltage, current, and temperature monitoring. The bottom of the cells directly contacts the liquid cooling plate for heat dissipation. Under normal circumstances, due to the inability of the cells to dissipate heat in a timely manner, the temperature difference within the cells and between cells in the battery pack exceeds 10°C. Therefore, the planar contact liquid cooling solution still suffers from three major technical bottlenecks: limited contact area, excessively high interfacial thermal resistance, and significant temperature gradients. Furthermore, due to the influence of actual operating conditions, cell charging and discharging cause volume expansion, generating shear stress at the planar contact interface. The actual contact area between the cell casing and the liquid cooling plate is only 60%~70% of the theoretical contact area, thus limiting the contact area. Planar contact is limited by surface flatness and assembly tolerances; fluctuations in the thickness of the thermally conductive interface material lead to uneven thermal resistance distribution, resulting in increased interfacial thermal resistance. Under high-current charging and discharging conditions, the temperature difference between the top and bottom of the cell often exceeds 8°C, resulting in a significant temperature gradient and accelerating local capacity decay. Therefore, it is necessary to design a new battery pack heat dissipation structure to solve the above problems. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies and provide a liquid cooling plate, a battery pack heat dissipation structure, and a battery pack with high thermal conductivity and better temperature field uniformity.

[0005] To achieve the above objectives, the technical solution of this utility model is implemented as follows: Based on one aspect of this utility model, a liquid cooling plate is provided, including an upper cooling plate for direct contact with the bottom of the battery cell and a lower cooling plate that cooperates with the upper cooling plate to form a liquid cooling channel. The upper cooling plate is folded to form a plurality of periodically arranged heat exchange serrations, and the heat exchange serrations are in the shape of a straight triangular prism with an inverted V-shaped orientation.

[0006] In one embodiment, the two triangular lateral faces of the heat exchange sawtooth along the horizontal width direction of the battery cell are the geometric bases of the right triangular prism. The height h of the triangular lateral face along the vertical height direction of the battery cell satisfies 0mm < h < h1, where h1 represents the maximum height of the battery cell along the vertical height direction, and 10mm < h1 < 1500mm. At the same time, the degree measure of one of the base angles α of the triangular lateral face along the horizontal length direction of the battery cell satisfies 15° < α < 90°.

[0007] In one embodiment, the two triangular lateral faces of the heat exchange sawtooth are isosceles triangles.

[0008] In one embodiment, the maximum vertical height H of the liquid cooling channel formed by the lower cooling plate and the heat exchange serrations satisfies h < H < (h + 5 mm).

[0009] In one embodiment, one heat exchange serration constitutes one cycle, and the number of heat exchange serrations n is related to the number of horizontal lengths L at the bottom of a single battery cell as follows: .

[0010] According to another aspect of the present invention, a battery pack heat dissipation structure is provided, including a battery cell and a liquid cooling plate as described in any of the preceding claims, wherein the heat exchange serrations are arranged along the horizontal length direction of the battery cell, and the bottom of the battery cell engages with the heat exchange serrations.

[0011] In one embodiment, the dimensions of the heat exchange serrations along the bottom width direction of the battery cell are the same as the bottom width of the battery cell.

[0012] According to another aspect of the present invention, a battery pack is provided, including the battery pack heat dissipation structure as described in any of the preceding claims.

[0013] In one embodiment, the liquid cooling channels adjacent to each other along the horizontal width direction of any cell are interconnected.

[0014] In one embodiment, adjacent cells are spaced apart along the horizontal length of any cell and separated by insulating shock-absorbing foam.

[0015] Compared with the prior art, the liquid cooling plate, battery pack heat dissipation structure and battery pack of this utility model have the following advantages: the upper surface of the liquid cooling plate is folded to form periodically arranged heat dissipation serrations, and the bottom of the battery cell engages with the opposite heat dissipation serrations one by one, increasing the contact area between the bottom of the battery cell and the liquid cooling plate. At the same time, multiple heat dissipation serrations form a multi-point three-dimensional heat conduction network, shortening the heat conduction path from the inside of the battery cell to the cooling medium. Furthermore, compared with the traditional planar contact, the tight engagement between the bottom of the battery cell and the heat dissipation serrations can better fill the interface gap, reduce the interface thermal resistance, and double the heat conduction efficiency.

[0016] In terms of optimizing temperature field uniformity, due to the full meshing contact with the heat dissipation serrations on the surface of the liquid cooling plate, the local maximum temperature at the bottom of the cell can be significantly reduced, the temperature gradient can be narrowed, the hot spot temperature rise is suppressed, the area of ​​the high temperature region is reduced, the lithium dendrite growth rate is slowed down, the risk of thermal runaway is reduced, and the cell life decay rate is significantly improved and the cycle life is improved under 3C continuous discharge conditions.

[0017] In terms of energy efficiency and space economy, the liquid cooling plate requires less coolant flow under the same heat dissipation requirements, saves pump power consumption, and improves system energy efficiency. While maintaining the same thermal management efficiency, the thickness of the liquid cooling plate can be reduced by 20%, which increases the volumetric energy density of the battery pack and optimizes space utilization.

[0018] The serrated structure at the bottom of the battery cell forms a topological interlock with the heat dissipation serrations of the liquid cooling plate, improving its resistance to vibration and shock. This avoids the interface delamination problem caused by long-term thermal cycling in planar contact, enhancing both interface stability and structural reliability. The irregular structure of the bottom of the battery cell and the liquid cooling plate is processed through cold pressing, making the increase in unit manufacturing cost and material cost controllable. It also has strong process compatibility, adapting to mainstream aluminum / copper battery cell casing stamping processes and being compatible with existing laser welding production lines. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a traditional planar contact battery pack heat dissipation structure. Figure 2 This is a schematic diagram of an embodiment of a battery pack heat dissipation structure according to the present invention; Figure 3 for Figure 2 A schematic diagram of the liquid cooling plate in the battery pack heat dissipation structure shown; Figure 4 for Figure 2 The diagram shows the structure of the battery cell in the heat dissipation structure of the battery pack. Figure 5 A schematic diagram of the heat dissipation structure of a battery pack with rectangular prism-shaped serrations for heat dissipation.

[0020] Explanation of reference numerals in the attached diagram: 1. Battery cell; 2. Liquid cooling plate; 21. Upper cooling plate; 211. Heat exchange serrations; 23. Lower cooling plate; 3. Liquid cooling channel. Detailed Implementation See also Figure 2-4 This embodiment provides a battery pack, including as follows: Figure 1 The battery pack heat dissipation structure shown includes cell 1 and... Figure 2The liquid cooling plate 2 shown includes an upper cooling plate 21 for direct contact with the bottom of the battery cell 1 and a lower cooling plate 23 that cooperates with the upper cooling plate 21 to form a liquid cooling channel 3. The upper cooling plate 21 is folded to form a plurality of periodically arranged heat exchange serrations 211. The heat exchange serrations 211 are arranged along the horizontal length direction of the bottom of the battery cell 1, and the bottom of the battery cell 1 engages with the heat exchange serrations 211. The dimension of the heat exchange serrations 211 along the width direction of the bottom of the battery cell 1 is the same as the width of the bottom of the battery cell 1. The battery cell 1 uses a copper battery cell shell, but it can also be an aluminum battery cell shell.

[0021] In this embodiment, the heat exchange sawtooth 211 is shaped like a right triangular prism with an inverted V-shape. The side edges of the right triangular prism extend along the horizontal width direction of the battery cell 1. The two triangular side faces of the heat exchange sawtooth 211 along the horizontal width direction of the battery cell 1 are the geometric bases of the right triangular prism. The triangular side faces are isosceles triangles, and the height h of the triangular side faces along the vertical height direction of the battery cell 1 satisfies 0mm < h < h 1, among which, h 1 represents the maximum height of cell 1 along the vertical direction, and 10mm < h 1 < 1500 mm, and simultaneously, the base angle α of the isosceles triangle satisfies 15° < α < 90°. The maximum vertical height H of the liquid cooling channel 3 formed by the lower cooling plate 23 and the heat exchange sawtooth 211 satisfies h < H < (h + 5 mm). One heat exchange sawtooth constitutes one cycle, and the number of heat exchange sawtooths... n Horizontal length of the bottom of a single cell 1 L The quantitative relationship is .

[0022] The battery pack heat dissipation structure in this embodiment, through geometric topology innovation, makes the contact surface between the bottom of the cell and the liquid cooling plate into a sawtooth-shaped irregular structure, forming a three-dimensional heat flow network. This effectively shortens the heat dissipation path, achieves a quality and efficiency upgrade of the heat conduction interface within a limited space, doubles the heat conduction efficiency, optimizes the temperature field uniformity, and comprehensively solves the heat dissipation bottleneck problem in high-current charging and discharging scenarios. Furthermore, the structure has enhanced reliability and strong process compatibility, while also considering energy efficiency and space economy, providing a new paradigm for battery pack thermal management design.

[0023] In other embodiments, the base angle α of the triangular side of the heat exchange serration 211 along the horizontal length of the battery cell can also be 30° or 60°. Along the bottom length of any battery cell 1, adjacent battery cells 1 arranged at intervals can also be separated by insulating shock-absorbing foam to make the bottom of the battery cell 1 mesh more stably with the heat exchange serration 211. Adjacent liquid cooling channels 3 along the horizontal width of any battery cell 1 can be configured to be interconnected.

[0024] The heat dissipation serrations in this embodiment are straight triangular prism-shaped battery pack heat dissipation structures. Figure 2 As shown) and the traditional planar contact type battery pack heat dissipation structure ( Figure 1 As shown), the heat dissipation serrations are a rectangular parallelepiped-shaped battery pack heat dissipation structure. Figure 5 The heat dissipation structures of the battery packs shown in the figure were compared experimentally. The specifications of each heat dissipation structure are as follows:

[0025] The specific experimental results are as follows: 1. Comparison of thermal performance parameters between traditional planar contact heat dissipation structures and straight triangular prism heat dissipation structures with serrated fins.

[0026] 2. Comparison of 1P cycle performance

[0027] 3. Comparison of cooling system energy consumption under 1P charging and discharging conditions

[0028] Compared to traditional planar contact battery pack heat dissipation structures, the heat dissipation structure of this embodiment features a liquid cooling plate with folded upper surface forming periodically arranged straight triangular prism-shaped heat dissipation serrations. The bottom of the battery cell engages with the opposite heat dissipation serrations one by one, increasing the contact area. Simultaneously, multiple heat dissipation serrations form a multi-point three-dimensional heat conduction network, shortening the heat conduction path from the inside of the battery cell to the cooling medium. Furthermore, compared to traditional planar contact, the tight engagement between the bottom of the battery cell and the heat dissipation serrations better fills the interface gaps, reducing interface thermal resistance and thus doubling the heat conduction efficiency. Due to the engagement contact with the heat dissipation serrations on the surface of the liquid cooling plate, the local maximum temperature at the bottom of the battery cell can be significantly reduced, the temperature gradient can be narrowed, the hot spot temperature rise is suppressed, the area of ​​the high-temperature region is reduced, the lithium dendrite growth rate is slowed down, the temperature field uniformity is optimized, and the risk of thermal runaway is reduced. Under 3C continuous discharge conditions, the battery cell life decay rate is significantly improved, and the cycle life is increased.

[0029] Furthermore, a comparison was made between a battery pack heat dissipation structure with cuboid heat dissipation serrations and a battery pack heat dissipation structure with straight triangular prism heat dissipation serrations.

[0030] 1. Energy density comparison

[0031] Compared to the rectangular heat dissipation serrations of the battery pack, the cross-sectional geometry of the straight triangular prism heat dissipation serrations allows for a thinner liquid cooling plate design. The heat dissipation serrations of the straight triangular prism battery pack heat dissipation structure have a more compact design and more efficient space utilization, thus showing more obvious advantages in terms of system energy density and space utilization.

[0032] 2. Comparison of 1P cycle performance

[0033] 3. Comparison of 1P discharge temperature performance

[0034] In terms of temperature uniformity, the battery pack heat dissipation structure with straight triangular prisms controls the maximum temperature difference of the battery to within 3.1℃, which is much lower than the 5.9℃ of the battery pack heat dissipation structure with cuboid prisms. Reducing the maximum temperature difference of the battery is a key factor in extending battery life, because a smaller temperature difference reduces the possibility of local overheating, thereby slowing down the capacity decay process.

[0035] Regarding the risk of thermal runaway, the area of ​​the heat dissipation junction of the battery pack with rectangular heat dissipation serrations exceeding 50°C accounts for 5.7%, which is almost 1.5 times that of the heat dissipation structure of the battery pack with straight triangular prism heat dissipation serrations. Local overheating can accelerate the decomposition of the SEI film and the growth of lithium dendrites, leading to the risk of thermal runaway. Therefore, compared with the rectangular triangular prism heat dissipation junction of the battery pack, the risk of thermal runaway can be better reduced.

[0036] 4. System Energy Efficiency Comparison

[0037] In terms of system energy efficiency, compared with the battery pack heat dissipation structure with rectangular heat dissipation serrations, the battery pack heat dissipation structure with straight triangular prisms with heat dissipation serrations reduces the required flow rate of liquid cooling plate under the same heat dissipation requirements, saves pump power consumption, and reduces the total system energy consumption.

[0038] 5. Comparison of Mechanical Performance and Cost Analysis

[0039] In terms of structural reliability, the battery pack heat dissipation structure with straight triangular prisms has a better resistance to vibration and shock than the battery pack heat dissipation structure with cuboid prisms, while keeping the increase in the manufacturing cost of individual units under control. It can avoid the interface delamination problem caused by long-term thermal cycling of planar contacts, and both interface stability and structural reliability are enhanced. In addition, the assembly time is shortened and the expected service life is longer.

[0040] Although the rectangular heat dissipation structure of the battery pack, with its serrated teeth, provides a larger theoretical contact area compared to the rectangular triangular prism heat dissipation structure, heat dissipation efficiency is not determined solely by the contact area. It is a complex process determined by heat conduction, heat convection, and contact thermal resistance. The rectangular triangular prism heat dissipation structure adjusts the heat exchange contact area between the bottom of the cell and the upper surface of the liquid cooling plate to a suitable range, significantly reducing interfacial thermal resistance, improving coolant convection efficiency, and achieving efficient and uniform heat flow paths.

[0041] The heat dissipation serrations are a rectangular battery pack heat dissipation structure. Heat transfer from the inside of the cell to the coolant requires a long path: cell casing → top of the rectangular heat dissipation serrations → neck of the rectangular heat dissipation serrations → root of the rectangular heat dissipation serrations → liquid cooling plate wall → coolant. The path is long, and especially at the neck of the rectangular heat dissipation serrations, there is a thermal bottleneck due to the small cross-section and high thermal resistance, which leads to heat flow congestion.

[0042] In this embodiment, the heat dissipation serrations are straight triangular prism-shaped battery pack heat dissipation structures, providing an extremely short and continuous heat flow path. Heat is directly transferred from the top of the serrations at the bottom of the cell to the meshing liquid cooling plate's heat dissipation serrations, with a very short conduction distance, only the height of the serrations. Subsequently, the heat is rapidly introduced into the liquid cooling plate substrate through the sides of the heat dissipation serrations, and finally reaches the coolant, forming a multi-point, parallel, short-path, highly efficient heat conduction network, avoiding local thermal bottlenecks. The heat dissipation serrations, being straight triangular prism-shaped battery pack heat dissipation structures, significantly reduce the internal thermal resistance of the material by shortening the heat flow path and eliminating cross-sectional bottlenecks. Although the heat dissipation contact area is relatively smaller, the heat flow rate is faster.

[0043] The contact thermal resistance between the bottom of the battery cell and the surface of the liquid cooling plate is often much greater than the thermal resistance of the material itself, caused by the unevenness and gaps of the contact surface. Compared with the battery pack heat dissipation structure with cuboid heat dissipation serrations, the heat dissipation serrations in this embodiment are straight triangular prisms, resulting in a more uniform pressure distribution at the meshing point. The beveled meshing of the V-shaped heat dissipation serrations provides a mechanism for self-centering and uniformly dispersing contact pressure, with the pressure evenly distributed across the bevels of all the V-shaped heat dissipation serrations, avoiding stress concentration. The uniform pressure at the bevels allows the thermal interface material to be compressed into a very thin and uniform film. Since the thermal conductivity of the TIM is inversely proportional to its thickness, the thinner the film, the lower the thermal resistance. The regular gaps formed by the straight triangular prism V-shaped heat dissipation serration structure are very suitable for the filling and compression of the TIM, effectively excluding air. When the battery cell expands, the beveled meshing of the V-shaped heat dissipation serrations can adapt through slight lateral displacement, rather than directly generating a peeling force as with traditional planar or cuboid heat dissipation serrations. This topological interlocking effect ensures the stability of the contact interface during thermal cycling, maintaining low contact thermal resistance over a long period. Therefore, the heat dissipation serrations in this embodiment are straight triangular prism-shaped battery pack heat dissipation structures. Through the uniform pressure distribution at the bevel engagement and the regular gaps at the bevel engagement, a thinner, more uniform, and more stable TIM layer can be obtained, reducing the biggest thermal resistance bottleneck—contact thermal resistance—to a level far lower than that of battery pack heat dissipation structures with cuboid heat dissipation serrations, thus achieving a performance improvement.

[0044] The battery pack heat dissipation structure of this embodiment utilizes the geometric characteristics of a straight triangular prism serrated structure, allowing for deeper and tighter engagement with virtually no gaps, maximizing the use of the theoretical contact surface. While a cuboid liquid cooling plate with serrated teeth is limited by its shape and cannot achieve the same filling effect, the direct increase in contact area and elimination of gaps play a crucial role in reducing thermal resistance. The three-dimensional heat flow network formed by the straight triangular prism serrated structure results in more uniform heat distribution, significantly improving temperature field uniformity. Due to the more efficient heat dissipation, a smaller coolant flow rate is required to maintain the same cooling effect, thereby reducing pump power. Furthermore, the topological interlocking of the straight triangular prism serrated structure provides strong mechanical locking force, superior to the simple reliance on pressure in a plane and the point-type connection of the straight triangular prism, resulting in the highest interface stability under vibration.

[0045] Although the total contact area between the bottom of the battery cell and the heat dissipation serrations in this embodiment is relatively smaller than that of the cuboid heat dissipation serrations, a better heat dissipation effect is still achieved by adjusting the heat exchange contact area to a suitable range, combined with shortening the heat flow path and reducing the contact thermal resistance. Overall, a leap in heat dissipation efficiency is achieved.

[0046] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0047] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A liquid-cooled plate, characterized in that, It includes an upper cooling plate (21) for direct contact with the bottom of the cell (1) and a lower cooling plate (23) that cooperates with the upper cooling plate (21) to form a liquid cooling channel (3). The upper cooling plate (21) is folded to form a number of periodically arranged heat exchange serrations (211). The heat exchange serrations (211) are straight triangular prisms with an inverted V-shaped orientation.

2. The liquid cooling plate as described in claim 1, characterized in that, The two triangular lateral faces of the heat exchange sawtooth (211) along the horizontal width direction of the battery cell (1) are the geometric bases of the right triangular prism, and the height of the triangular lateral faces along the vertical height direction of the battery cell (1) is... h Satisfying 0mm < h < h 1, among which, h 1 indicates the maximum height of the battery cell (1) in the vertical direction, and 10mm < h 1 < 1500 mm, and at the same time, the degree of one of the base angles α of the side of the triangle along the horizontal length direction of the battery cell (1) satisfies 15° < α < 90°.

3. The liquid cooling plate as described in claim 2, characterized in that, The two triangular lateral faces of the heat exchange sawtooth (211) are isosceles triangles.

4. The liquid cooling plate as described in claim 2 or 3, characterized in that, The maximum vertical height H of the liquid cooling channel (3) formed by the lower cooling plate (23) and the heat exchange sawtooth (211) satisfies h < H < (h + 5 mm).

5. The liquid-cooled plate as described in claim 2 or 3, characterized in that, One heat exchange sawtooth (211) constitutes one cycle, and the number of heat exchange sawtooths (211) is... n The horizontal length of the bottom of a single cell (1) L The quantitative relationship is .

6. A battery pack heat dissipation structure, characterized in that, Includes a battery cell (1) and a liquid cooling plate as described in any one of claims 1-5, wherein the heat exchange serrations (211) are arranged along the horizontal length direction of the battery cell (1), and the bottom of the battery cell (1) engages with the heat exchange serrations (211).

7. The battery pack heat dissipation structure as described in claim 6, characterized in that, The dimensions of the heat exchange sawtooth (211) along the bottom width direction of the battery cell (1) are the same as the bottom width of the battery cell (1).

8. A battery pack, characterized in that, Includes the battery pack heat dissipation structure as described in claim 6 or 7.

9. The battery pack as described in claim 8, characterized in that, The liquid cooling channels (3) adjacent to each other along the horizontal width direction of any cell (1) are interconnected.

10. The battery pack as claimed in claim 8, characterized in that, Adjacent cells (1) are arranged at intervals along the horizontal length direction of any cell (1) and separated by insulating shock-absorbing foam.

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