Spider web runner cold plate for heat dissipation of lithium battery

Abstract

The invention innovatively provides a spider web flow channel cold plate based on lithium battery heat dissipation, belongs to the field of battery heat management, and realizes remarkable improvement of three-dimensional heat management efficiency through topological optimization of a radial main channel and a net-shaped straight branch. Compared with a traditional straight flow channel and snake-shaped flow channel scheme, the structure effectively eliminates heat dissipation blind areas at the tail end and the edge area of the battery module through a multi-stage branch collaborative heat dissipation mechanism, and reduces energy consumption; compared with a vein flow channel, the structure adopts the net-shaped straight branch, the phenomenon that the pressure drop of the fractal tip of the vein flow channel is suddenly increased due to section shrinkage under the high-speed flow state is effectively eliminated, and the system pressure drop is reduced by 9% under the working condition of the high flow speed of 0.3 m / s; the problem that the temperature difference is increased due to the fact that laminar flow dominates and weakens the convective heat transfer coefficient when the vein flow channel is at a low speed is effectively solved, and the temperature gradient under the working condition of the low flow speed of 0.01 m / s is reduced by 22%.

Description

Technical Field

[0001] The invention belongs to the field of battery thermal management, and in particular relates to a spider web flow channel cold plate for heat dissipation of a lithium battery pack. Background Art

[0002] As the core power unit of new energy vehicles, the thermal management efficiency of lithium batteries is directly related to the performance and safety of the entire vehicle. However, the temperature control problem caused by the heat generated by the internal resistance of the battery pack during operation (especially the temperature rise rate of up to 10°C / min under fast charging / fast discharging conditions) has always been a key bottleneck restricting the development of high-energy density battery technology. Studies have shown that when the battery temperature exceeds the optimal operating range of 20-40°C, its cycle life will decrease by about 2% for every 1°C increase; if the local temperature difference exceeds 5°C, it will cause irreversible damage such as accelerated lithium dendrite growth and SEI film rupture, and even induce a thermal runaway chain reaction.

[0003] The current mainstream liquid cooling system achieves heat exchange by pumping coolant through the liquid cooling plate microchannels between battery modules. Its heat dissipation efficiency is highly dependent on the optimized design of the flow channel topology. The ideal flow channel needs to meet multiple constraints: maintaining turbulent enhanced heat transfer under limited pressure drop, controlling the temperature difference between modules through balanced flow distribution, and avoiding heat accumulation due to local flow dead zones. Although traditional designs such as parallel straight flow channels have low flow resistance characteristics, they lead to uneven heat dissipation due to the attenuation of flow at the end; although the serpentine flow channel prolongs the residence time of the coolant, the eddy current loss caused by frequent bending causes the pump power demand to surge by more than 30%, and the elbow area is prone to form a temperature gradient. In recent years, bionic flow channel design (such as leaf vein fractal network) has made progress in improving heat dissipation uniformity by simulating natural transport systems, but it still faces the challenge of insufficient adaptability to dynamic working conditions: under high-speed flow, the pressure drop at the end of the fractal increases sharply due to the contraction of the cross section, while the dominance of laminar flow at low speeds weakens the convective heat transfer coefficient. In response to the above technical pain points, this study innovatively proposed a lithium battery liquid cooling plate design based on spider web bionic topology. Compared with the leaf vein flow channel, this structure is achieved through the coordination of radial main channels and mesh branches (such as Figure 3 As shown in Figure 2), the temperature difference is reduced by 22% under the low flow rate of 0.01m / s, and the pressure drop is reduced by 9% under the high flow rate of 0.3m / s (as shown in Figure 2). Figure 7 The results are shown in Figure 2), which is significantly better than the leaf vein scheme. Summary of the invention

[0004] The object of the present invention is to provide a spider web-shaped flow channel for heat dissipation of a lithium battery pack, which has the advantages of low power consumption and good cooling performance.

[0005] The technical solution of the present invention is as follows: a spider web-like flow channel cold plate for heat dissipation of lithium batteries, including a heat-conducting top plate and a bottom plate, the top plate is connected to the bottom plate, the bottom plate is provided with a liquid inlet channel, a liquid outlet channel, and a plurality of branch channels; the liquid inlet channel is located at the top of the bottom plate, the liquid outlet channel is located at the bottom of the bottom plate, and the plurality of branch channels include a primary branch channel, a secondary branch channel, a tertiary branch channel, a fourth branch channel, and a fifth branch channel. The primary branch channel and the secondary branch channel are symmetrical with the fourth branch channel and the fifth branch channel respectively, so that the heat dissipation on both sides of the battery is uniform. The tertiary branch channel adopts a straight structure, which reduces the pressure drop as much as possible while ensuring the cooling effect.

[0006] As a feature of the present invention, the liquid inlet flow channel is interconnected with the adjacent first-level branch flow channels, each of the first-level branch flow channels is interconnected with each of the second-level branch flow channels, each of the second-level branch flow channels is interconnected with each of the third-level branch flow channels, each of the third-level branch flow channels is interconnected with each of the fourth-level branch flow channels, each of the fourth-level branch flow channels is interconnected with the fifth-level branch flow channels, and each of the fifth-level branch flow channels is interconnected with the liquid outlet flow channel.

[0007] As a feature of the present invention, in order to ensure that the coolant stays in the flow channel for a longer time, the sum of the number of primary branch flow channels and secondary branch flow channels is greater than the number of straight tertiary branch flow channels. The number of the inlet flow channel is 1, the number of the primary branch flow channels is 3, the number of the secondary branch flow channels is 7, the number of the tertiary branch flow channels is 6, the number of the quaternary branch flow channels is 7, the number of the quinary branch flow channels is 3, and the number of the outlet flow channels is 1. As a feature of the present invention, the first-level tributary flow channel is composed of an inclined first-level tributary flow channel and a vertical first-level tributary flow channel, the number of the inclined first-level tributary flow channels is 2, the number of the vertical first-level tributary flow channels is 1, and the first-level tributary flow channel is interconnected with the adjacent second-level tributary flow channel 13; the second-level tributary flow channel is composed of an inclined second-level tributary flow channel and a vertical second-level tributary flow channel, the number of the inclined second-level tributary flow channels is 2, the number of the vertical second-level tributary flow channels is 5, and the vertical second-level tributary flow channel is interconnected with the adjacent third-level tributary flow channel 14.

[0008] As a feature of the content of the present invention, it has been verified by simulation that the effect is better when the size is within the following range: the width of the liquid inlet channel is A, and the size of A is between 20 and 30, the width of the vertical primary tributary channel is B, which satisfies B=2 / 3A, the width H of the inclined primary tributary channel satisfies H=1 / 2B, the width C of the secondary vertical tributary channel satisfies C=1 / 2B, the distance G between two adjacent secondary vertical tributary channels meets G=2 / 3B, the width D of the tertiary tributary channel satisfies D=G, the width I of the tertiary tributary channel merging into the quaternary tributary channel satisfies I=C, the width E of the quintuple tributary channel satisfies E=B, and the width F of the liquid outlet channel satisfies F=A; the angle between the inclined primary tributary channel and the liquid inlet channel is The angle between the inclined secondary branch flow channel and the vertical secondary branch flow channel is .

[0009] The beneficial effects of the present invention are as follows: The present invention innovatively proposes a spider web flow channel structure based on the bionics principle. The design is achieved by topological optimization of the radial main channel and the mesh straight branch ( Figure 3 ), achieving a significant improvement in the three-dimensional thermal management efficiency. Compared with the traditional leaf vein flow channel and serpentine flow channel solution, this structure effectively eliminates the heat dissipation blind spots at the end and edge of the battery module through a multi-level branch collaborative heat dissipation mechanism, and reduces energy consumption; compared with the leaf vein flow channel, this structure uses a mesh straight branch, which effectively eliminates the sharp increase in pressure drop due to cross-sectional contraction at the fractal end of the leaf vein flow channel under high-speed flow, reducing the system pressure drop by 9% under 0.3m / s high flow rate conditions ( Figure 7 ), and adopts radial main channels, which effectively solves the problem that laminar flow dominates the vein flow channel at low speed, weakening the convective heat transfer coefficient and increasing the temperature difference, and reduces the temperature gradient by 22% under the low flow rate condition of 0.01m / s. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is an exploded view of the overall structure of the present invention; Figure 3 It is a schematic diagram of the top plate structure of the present invention; Figure 4 This is a schematic diagram of the structure and dimensions of the spider web flow channel of the present invention; Figure 5 This is a schematic diagram of a lithium battery used in the present invention; Figure 6 Schematic diagram of the coolant flow direction in the spider web flow channel structure of the present invention Figure 7 This is a comparison diagram of the cooling effect and pressure drop of the spider web and leaf vein flow channels of the present invention.

[0011] Numbers in the figure: 1. Top plate; 2. Bottom plate; 3. Combination of top plate and bottom plate; 4. Lithium battery; 11. Liquid inlet channel; 12. Primary branch channel; 13. Secondary branch channel; 14. Third branch channel; 15. Fourth branch channel; 16. Fifth branch channel; 17. Liquid outlet channel; 121. Vertical primary branch channel; 122. Inclined primary branch channel; 131. Vertical secondary branch channel; 132. Inclined secondary branch channel. DETAILED DESCRIPTION

[0012] The following describes the embodiments of the present invention in conjunction with examples and drawings: Embodiment 1, by attachment 1, attachment Figure 2 and attached Figure 3 The spider web flow channel cold plate includes a top plate 1 and a bottom plate 2, the top plate 1 is fixedly connected to the bottom plate 2, the top plate 1 is connected to the bottom plate 2, the bottom plate 2 is provided with an inlet flow channel 11, an outlet flow channel 12, and a plurality of branch flow channels; the inlet flow channel 11 is located at the top of the bottom plate 2, the outlet flow channel 17 is located at the bottom of the bottom plate 2, and the plurality of branch flow channels include a primary branch flow channel 12, a secondary branch flow channel 13, a tertiary branch flow channel 14, a fourth branch flow channel 15, and a fifth branch flow channel 16. The secondary branch flow channel 13 and the tertiary branch flow channel 14 are symmetrical with the fourth branch flow channel 15 and the fifth branch flow channel 16 respectively.

[0013] The number of liquid inlet flow channels 11 is 1, the number of first-level branch flow channels 12 is 3, the number of second-level branch flow channels 13 is 7, the number of third-level branch flow channels 14 is 6, the number of fourth-level branch flow channels 15 is 7, the number of fifth-level branch flow channels 16 is 3, and the number of liquid outlet flow channels 17 is 1.

[0014] The first-level tributary flow channel 12 is composed of an inclined first-level tributary flow channel 122 and a vertical first-level tributary flow channel 121, the number of the inclined first-level tributary flow channels 122 is 2, the number of the vertical first-level tributary flow channels 121 is 1, the first-level tributary flow channel 12 is interconnected with the adjacent second-level tributary channel 13, the second-level tributary flow channel 13 is composed of an inclined second-level tributary flow channel 132 and a vertical second-level tributary flow channel 131, the number of the inclined second-level tributary flow channels 132 is 2, the number of the vertical second-level tributary flow channels 131 is 5, and the vertical second-level tributary flow channel 131 is interconnected with the adjacent third-level tributary flow channel 14.

[0015] By the attached Figure 4, the width of the inlet channel is A, A is selected in the range of 20~30mm, the width of the primary tributary channel 11 is B, which meets B=2 / 3A, the width H of the inclined primary tributary channel 122 satisfies H=1 / 2B, the width C of the vertical secondary tributary channel 131 satisfies C=1 / 2B, the distance G between two adjacent vertical secondary tributary channels 131 meets G=2 / 3B, the width D of the tertiary tributary channel 14 satisfies D=G, the width I of the tertiary tributary channel 14 merging into the quaternary tributary channel 15 satisfies I=C, the width E of the quintuple tributary channel 15 satisfies E=B, and the width F of the outlet channel 17 satisfies F=A; the angle between the inclined primary tributary channel 122 and the inlet channel 11 is The angle between the inclined secondary branch flow channel 132 and the vertical secondary branch flow channel 131 is .

[0016] In this example, A is selected as 25 mm, and then it can be calculated that: B is 16.7 mm, C is 8.3 mm, H is 8.35 mm, G is 11.1 mm, D is 11.1 mm, and F is 25 mm. The angle between the inclined primary branch flow channel 122 and the liquid inlet flow channel 11 is selected as α=120°, and the angle between the inclined secondary branch flow channel 132 and the vertical secondary branch flow channel 131 is 0°.

[0017] See attached Figure 5 and attached Figure 6 When the normally discharged lithium battery liquid cooling plate is working, the surface of one side of the bottom plate 2 is closely attached to the surface of the lithium battery 4, the heat generated by the lithium battery 4 is transferred to the bottom plate 2, and the heat on the bottom plate 2 is transferred to the top plate 1, and then the coolant in the bottom plate 2 takes away the heat absorbed by the top plate 1 and the bottom plate 2. The coolant enters the primary branch flow channel 12 from the liquid inlet channel 11, enters each secondary branch flow channel 13 from the primary branch flow channel 12, enters each tertiary branch flow channel 14 from the secondary branch flow channel 13, flows from the tertiary branch flow channel 14 into the quaternary branch flow channel 15, flows from the quaternary branch flow channel 15 into the fifth branch flow channel 16, and flows out of the cold plate from the fifth branch flow channel 16 through the liquid outlet channel 17.

[0018] The present invention adopts a bionic spider web flow channel, through the topological optimization of the radial main channel and the mesh straight branch ( Figure 3 ), achieving a significant improvement in the three-dimensional thermal management efficiency. Compared with the traditional leaf vein flow channel and serpentine flow channel solution, this structure effectively eliminates the heat dissipation blind spots at the end and edge of the battery module through a multi-level branch collaborative heat dissipation mechanism, and reduces energy consumption; compared with the leaf vein flow channel, this structure uses a mesh straight branch, which effectively eliminates the sharp increase in pressure drop due to cross-sectional contraction at the fractal end of the leaf vein flow channel under high-speed flow, reducing the system pressure drop by 9% under 0.3m / s high flow rate conditions ( Figure 7 ), and adopts radial main channels, which effectively solves the problem that laminar flow dominates the vein flow channel at low speed, weakening the convective heat transfer coefficient and increasing the temperature difference, and reduces the temperature gradient by 22% under the low flow rate condition of 0.01m / s.

Claims

1. A spider web-like flow channel cold plate for heat dissipation of lithium batteries, comprising a top plate (1) and a bottom plate (2), characterized in that: The top plate (1) is fixedly connected to the bottom plate (2); the bottom plate (2) is provided with a liquid inlet channel (11), a primary branch channel (12), a secondary branch channel (13), a tertiary branch channel (14), a quaternary branch channel (15), a quintuple branch channel (16), and a liquid outlet channel (17); the liquid inlet channel (11) is located at the top of the bottom plate (2), and the liquid outlet channel (17) is located at the bottom of the bottom plate (2); the primary branch channel (12), the secondary branch channel (13), the tertiary branch channel (14), the quaternary branch channel (15), and the quintuple branch channel (16) are all located between the liquid inlet channel (11) and the liquid outlet channel (17).

2. The spider web flow channel cold plate for heat dissipation of lithium batteries according to claim 1, characterized in that: The liquid inlet flow channel (11) is interconnected with the adjacent primary branch flow channel (12), each of the primary branch flow channels (12) is interconnected with each of the secondary branch flow channels (13), each of the secondary branch flow channels (13) is interconnected with each of the tertiary branch flow channels (14), each of the tertiary branch flow channels (14) is interconnected with the quaternary branch flow channel (15), each of the quaternary branch flow channels (15) is interconnected with the quintuple branch flow channel (16), and each of the quintuple branch flow channels (16) is interconnected with the liquid outlet flow channel (17). The secondary branch flow channel (13) and the tertiary branch flow channel (14) are symmetrical with the quaternary branch flow channel (15) and the quintuple branch flow channel (16) respectively, so that the heat dissipation on both sides and the end of the battery is uniform. The tertiary branch flow channel (14) adopts a straight structure, so that the pressure drop is reduced as much as possible while ensuring the cooling effect.

3. According to the spider web flow channel cold plate for heat dissipation of lithium batteries as claimed in claim 1, in order to ensure that the coolant stays in the flow channel for a longer time, the total number of the primary branch flow channels (12) and the secondary branch flow channels (13) is greater than the number of the straight tertiary branch flow channels (14), the number of the inlet flow channels (11) is 1, the number of the primary branch flow channels (12) is 3, the number of the secondary branch flow channels (13) is 7, the number of the tertiary branch flow channels (14) is 6, the number of the quaternary branch flow channels (15) is 7, the number of the quinary branch flow channels (16) is 3, and the number of the outlet flow channels (17) is 1.

4. The spider web flow channel cold plate for heat dissipation of lithium batteries according to claim 1, characterized in that: The first-level tributary flow channel is composed of an inclined first-level tributary flow channel (122) and a vertical first-level tributary flow channel (121), the number of the inclined first-level tributary flow channels (122) is 2, the number of the vertical first-level tributary flow channels (121) is 1, and the first-level tributary flow channel (12) is interconnected with an adjacent second-level tributary flow channel (13); the second-level tributary flow channel (13) is composed of an inclined second-level tributary flow channel (132) and a vertical second-level tributary flow channel (131), the number of the inclined second-level tributary flow channels (132) is 2, the number of the vertical second-level tributary flow channels (131) is 4, and the vertical second-level tributary flow channel (131) is interconnected with an adjacent third-level tributary flow channel (14).

5. According to claim 1, a spider web flow channel cold plate for heat dissipation of lithium batteries, after simulation verification, the effect is better when the size is within the following range: the width of the liquid inlet flow channel (11) is A, A is selected in the range of 20-30 mm, the width of the primary branch flow channel (12) is B, which meets B=2 / 3A, the width H of the inclined primary branch flow channel (122) satisfies H=1 / 2B, the width C of the vertical secondary branch flow channel (131) meets C=1 / 2B, and the distance G between two adjacent vertical secondary branch flow channels (131) meets G=2 / 3B The width of the tertiary branch flow channel (14) is D=G, the width of the tertiary branch flow channel (14) merging into the quaternary branch flow channel (15) is I=C, the width of the quintuple branch flow channel (16) is E=B, and the width of the outlet flow channel (17) is F=A; the angle between the inclined secondary branch flow channel (132) and the primary branch flow channel (12) is α=120°~145°, and the angle between the inclined secondary branch flow channel (132) and the vertical secondary branch flow channel (131) is β=45°~60°.

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