Double-layer fractal flow channel liquid cooling plate

Abstract

The utility model discloses a double-layer fractal flow channel liquid cooling plate. The flow channel liquid cooling plate comprises an upper-layer flow channel plate, a middle plate and a lower-layer flow channel plate, a flow channel is machined through a machining method or integrally machined through a mold and connected in a brazing mode, the flow channel of the upper-layer flow channel plate and the flow channel of the lower-layer flow channel plate are connected through a hollow-out flow channel of the middle plate, and multiple parallel channels and special-structure flow channels with gradually-changed widths are arranged in the flow channel. Two pipelines are arranged above the upper-layer runner plate and are respectively connected with the upper-layer runner and the lower-layer runner, and the two pipelines are respectively an outlet and an inlet. When the cooling liquid is led in from the inlet and led out from the outlet, the cooling liquid passes through a double-layer flowing process in different up-down directions in the flow channel, so that the temperature uniformity of the battery pack can be adjusted while the temperature of the battery pack is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery pack radiator, especially a double-layer fractal flow channel liquid cooling plate. BACKGROUND

[0002] In recent years, new energy vehicles develop rapidly, and the safety and working efficiency of power batteries as the power source of new energy vehicles cannot be ignored. In the battery charging and discharging process, the battery will heat and temperature rise, and a temperature difference will also be formed between single batteries in the battery pack. Overly high temperature will cause the chemical reaction in the battery to intensify, and in severe cases, even liquid leakage, gas emission, smoke emission and explosion can occur. In addition, if the temperature uniformity of each battery cannot be effectively controlled, the temperature in the battery box will be unstable, reducing the performance of the power battery, and even causing thermal runaway. Today's power batteries, such as lithium ion batteries, have a higher energy density and heat generation. In order to efficiently utilize the power battery, it is imperative to design a high-efficiency, uniform heat transfer liquid cooling plate structure to control the battery pack temperature and temperature uniformity within an ideal range.

[0003] A conventional single-layer flow channel liquid cooling plate, such as the patent "Bionic liquid cooling device for lithium ion battery equalization heat dissipation" with publication (announcement) number CN 219892241U, uses a single-layer flow channel to achieve the flow of working fluid from one end to the other end. The structure is a tree leaf vein bionic topological flow channel structure composed of a main flow channel and multiple straight channels. The outlet section of this single-layer, one-way flow channel cooling plate has a relatively high temperature, which can easily cause the temperature of the battery to be uneven.

[0004] At present, the main power battery cooling scheme is to set a single-layer flow channel liquid cooling plate with a one-way flow channel at the bottom of the battery pack. The battery is cooled by using the convective heat transfer effect of the cooling liquid. The temperature around the outlet of the single-layer flow channel liquid cooling plate is relatively high, which further affects the temperature of the battery at the outlet section, and to some extent, affects the cooling effect and the temperature uniformity of the battery pack. SUMMARY

[0005] In order to overcome the problem that the existing single-layer liquid cooling plate cannot uniformly control the temperature of the entire cooling plate and even the battery, the double-layer fractal flow channel liquid cooling plate provides two layers of fractal flow channels with different flow directions and non-unique flow channels, which can enhance heat transfer while considering temperature uniformity.

[0006] The utility model solves its technical problem, and the utility model designs a double-layer fractal flow channel liquid cooling plate, which comprises a lower flow channel plate, an intermediate plate and an upper flow channel plate, and is characterized by:

[0007] The upper surface of the lower layer flow channel plate is processed with a first flow channel through which fluid flows, and the first flow channel comprises a lower layer zero-level flow channel, a lower layer first-level flow channel, a lower layer second-level flow channel and a lower layer third-level flow channel; the lower layer zero-level flow channel is arranged in the shape of a lower-case h with two parallel flow channels of different lengths, the shorter flow channel of the lower layer zero-level flow channel is connected to the length symmetry line of the longer flow channel through a vertical flow channel, the longer flow channel of the lower layer zero-level flow channel is connected to 2-4 lower layer first-level flow channels parallel to each other, each lower layer first-level flow channel leads out several lower layer second-level flow channels parallel to both sides, and the end of the lower layer second-level flow channel intersects with a lower layer third-level flow channel parallel to the lower layer first-level flow channel;

[0008] The intermediate plate comprises a hollow flow channel and an inlet hole, the lower surface of the upper layer flow channel plate is processed with a second flow channel through which fluid flows, and the second flow channel comprises an upper layer zero-level flow channel, an upper layer first-level flow channel, an upper layer second-level flow channel and an upper layer third-level flow channel, and an inlet pipeline and an outlet pipeline are arranged;

[0009] The upper layer zero-level flow channel and the lower layer zero-level flow channel are symmetrically distributed along the vertical flow channel, the upper layer first-level flow channel, the upper layer second-level flow channel and the upper layer third-level flow channel are arranged in the same way as the lower layer first-level flow channel, the lower layer second-level flow channel and the lower layer third-level flow channel;

[0010] The upper layer third-level flow channel is in one-to-one correspondence with the lower layer third-level flow channel through the hollow flow channel of the intermediate plate, the inlet pipeline is in communication with the shorter flow channel of the lower layer zero-level flow channel through the inlet hole, and the outlet pipeline is in communication with the shorter flow channel of the upper layer zero-level flow channel.

[0011] The flow direction of fluid in the upper layer first-level flow channel and the lower layer first-level flow channel is opposite;

[0012] And / or the flow direction of fluid in the lower layer second-level flow channel and the upper layer second-level flow channel is opposite.

[0013] The width of the upper layer first-level flow channel gradually decreases in the direction away from the upper layer zero-level flow channel;

[0014] And / or the width of the lower layer first-level flow channel gradually decreases in the direction away from the lower layer zero-level flow channel;

[0015] And / or the width of the upper layer third-level flow channel gradually decreases in the direction close to the upper layer zero-level flow channel;

[0016] And / or the width of the lower layer third-level flow channel gradually decreases in the direction close to the lower layer zero-level flow channel;

[0017] And / or the width of the hollow flow channel gradually decreases in the direction close to the lower layer zero-level flow channel.

[0018] The width reduction ratios of the upper layer first-level flow channel, the lower layer first-level flow channel, the upper layer third-level flow channel, the lower layer third-level flow channel and the hollow flow channel are the same, and the width reduction ratio is in the range of 0.3-0.7.

[0019] The upper layer zero-level flow channel of the upper layer flow channel plate is fractal into 2-4 upper layer first-level flow channels, the upper layer first-level flow channels are also connected in parallel with a plurality of upper layer second-level flow channels on both sides, tail portions of the upper layer second-level flow channels are vertically communicated with upper layer third-level flow channels, and an angle between the flow channels when being connected with each other is 90 degrees.

[0020] And / or the lower layer zero-level flow channel of the lower layer flow channel plate is fractal into 2-4 lower layer first-level flow channels, the lower layer first-level flow channels are also connected in parallel with a plurality of lower layer second-level flow channels on both sides, tail portions of the lower layer second-level flow channels are vertically communicated with lower layer third-level flow channels, and an angle between the flow channels when being connected with each other is 90 degrees.

[0021] The average width of the upper layer first-level flow channel is 2 times of the average width of the upper layer third-level flow channel, and a spacing between two adjacent upper layer second-level flow channels is 20-40 mm.

[0022] And / or the average width of the lower layer first-level flow channel is 2 times of the average width of the lower layer third-level flow channel, and a spacing between two adjacent lower layer second-level flow channels is 20-40 mm.

[0023] Further, water, ethylene glycol or a mixed solution of the two is used as the cooling working medium.

[0024] The liquid cooling plate has the advantages that the flowing working medium in the cooling plate flows in different directions through the double layers, and the cooling efficiency of the liquid cooling plate and the problem of uniformity of the battery temperature are effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] The utility model is further described below in combination with the drawings and examples.

[0026] Figure 1 It is a three-dimensional explosion view of a double-layer fractal flow channel liquid cooling plate.

[0027] Figure 2 It is a flow channel distribution and size schematic view of a lower layer flow channel plate of a double-layer fractal flow channel liquid cooling plate.

[0028] Figure 3 It is an up-down overturning schematic view of an upper layer flow channel plate of a double-layer fractal flow channel liquid cooling plate.

[0029] Figure 4 It is a schematic view of a middle plate of a double-layer fractal flow channel liquid cooling plate.

[0030] Figure 5 It is a flow path direction schematic view of a double-layer fractal flow channel liquid cooling plate.

[0031] Figure 6 It is a single-layer bionic vein flow channel liquid cooling plate structure schematic view.

[0032] Figure 7is two liquid cooling plate temperature cloud atlas comparison chart.

[0033] Figure 8 is two liquid cooling plate temperature index comparison chart.

[0034] Fig. 1. upper layer flow channel plate, 2. middle plate, 3. lower layer flow channel plate, 4. zero level flow channel, 5. first level flow channel, 6. second level flow channel, 7. third level flow channel, 8. outlet pipe, 9. inlet pipe, 10. middle plate hollow flow channel, 11. middle plate inlet hole, 12 single layer bionic vein flow channel liquid cooling plate, 13. inlet flow channel, 14. outlet flow channel, 15. bionic vein channel. DETAILED DESCRIPTION

[0035] The technical scheme in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments.

[0036] For the convenience of understanding, the zero level flow channel 4 of the device respectively indicates the upper layer zero level flow channel and the lower layer zero level flow channel; the first level flow channel 5 respectively indicates the upper layer first level flow channel and the lower layer first level flow channel; the second level flow channel 6 respectively indicates the upper layer second level flow channel and the lower layer second level flow channel; and the third level flow channel 7 respectively indicates the upper layer third level flow channel and the lower layer third level flow channel.

[0037] As shown in the figure, the utility model discloses a double layer fractal flow channel liquid cooling plate, which comprises an upper layer liquid cooling plate 1, a middle plate 2 and a lower layer liquid cooling plate 3. Figure 1 As shown in the figure, the first flow channel in the lower layer flow channel plate 3 comprises a zero level flow channel 4, a first level flow channel 5, a second level flow channel 6 and a third level flow channel 7. Figure 2 The shorter flow channel end is connected to the length symmetry line of the longer flow channel through a vertical flow channel, the longer flow channel is connected to 2-4 first level flow channels 5 through a first level channel extension connecting section, a plurality of second level flow channels 6 are respectively fractalized from the two sides of the plurality of first level flow channels 5, and finally, the third level flow channels 7, the number of which is twice the number of the first level flow channels 5, are formed.

[0038] As shown in the figure, the second flow channel of the upper layer flow channel plate 1 comprises a zero level flow channel 4, a first level flow channel 5, a second level flow channel 6 and a third level flow channel 7. Figure 3 The first level flow channel, the second level flow channel and the third level flow channel correspond to the lower layer flow channel plate 3, the zero level flow channel 4 of the upper layer flow channel plate 1 is symmetrical to the zero level flow channel 4 of the lower layer flow channel plate 3, an outlet pipe 8 is connected to the end of the zero level flow channel 4 of the upper layer flow channel plate 1, and an inlet pipe 9 is arranged symmetrically with the outlet pipe 8.

[0039] As shown in the figure, the second flow channel of the upper layer flow channel plate 1 comprises a zero level flow channel 4, a first level flow channel 5, a second level flow channel 6 and a third level flow channel 7. Figure 4As shown, the intermediate plate 2 is composed of intermediate plate hollow flow channels 10 and inlet holes 11. The number, size and position of the hollow flow channels 10 correspond to those of the tertiary flow channels 7, and the inlet holes 11 correspond to the inlet pipes 9.

[0040] Further, the upper flow channel plate 1, the intermediate plate 2 and the lower flow channel plate 3 have the same length and width, the primary flow channels 5, the secondary flow channels 6 and the tertiary flow channels 7 in the upper flow channel plate 1 and the lower flow channel plate 3 have the same size and position, and the zero-order flow channels 4 of the two are in a mirror-symmetrical relationship. The hollow flow channels 10 of the intermediate plate 2 have the same number, size and position as the tertiary flow channels 7 in the upper flow channel plate 1 and the lower flow channel plate 3. The inlet pipes 8 and the outlet pipes 9 are located at the tail of the zero-order flow channels 4, and the distance between the centers of the pipes and the two sides of the zero-order flow channels 4 is the same.

[0041] Further, the slot cross sections of the zero-order flow channels 4, the primary flow channels 5, the secondary flow channels 6 and the tertiary flow channels 7 in the upper flow channel plate 1 and the lower flow channel plate 3 are all square.

[0042] Further, the width of the primary flow channels 5 in the upper flow channel plate and the lower flow channel plate decreases from the connection with the first secondary flow channel 6, and decreases in the direction away from the zero-order flow channel 4. The width of the tertiary flow channels 7 and the hollow flow channels 10 gradually decreases in the direction close to the zero-order flow channel 4. The width of the primary flow channels 5, the tertiary flow channels 7 and the hollow flow channels 10 decreases at the same rate, and the value range is 0.3-0.7.

[0043] Further, the average width of the primary flow channels 5 except the connection section is twice the average width of the tertiary flow channels 7. The distance between the two adjacent secondary flow channels 6 is 10-50mm. The slot depth of the zero-order flow channels 4, the primary flow channels 5, the secondary flow channels 6 and the tertiary flow channels 7 is consistent. The inner hole diameter of the outlet pipes 8 and the inlet pipes 9 of the upper flow channel plate 1 is half of the width of the zero-order flow channels 4.

[0044] Further, as shown in FIG. 1, the upper flow channel plate 1, the intermediate plate 2 and the lower flow channel plate 3 are arranged in a stack, and the upper flow channel plate 1 and the lower flow channel plate 3 are connected by the intermediate plate 2. Figure 2As shown, in a preferred embodiment of a double-layer fractal flow channel liquid cooling plate, the distribution and dimensions of the flow channels in the lower flow channel plate are as follows: the width of the zero-stage flow channel 4 ranges from 30mm to 40mm, with 30mm used in this example; the zero-stage flow channel 4 is fractally divided into 2-4 primary flow channels 5, with 3 primary flow channels 5 used in this example; the width of the connecting section from the primary channel 5 to the zero-stage channel 4 is the maximum width of the primary channel, and the length is between 50-100mm, with 70mm used in this example; the average width of the primary flow channel 5, excluding the connecting section, is twice the average width of the tertiary flow channel 7. The average width of primary channel 5, excluding the connecting section, ranges from 10-30 mm, with 20 mm used in this example. The number of parallel secondary channels 6 in each column ranges from 20-30, with 24 used in this example; their widths range from 0.5-1.5 mm, with 0.5 mm used in this example; the spacing is 20-40 mm, with 30 mm used in this example. The width reduction ratio of primary channel 5, tertiary channel 7, and hollowed-out channel 10 ranges from i = 0.3-0.7, with i = 0.5 used in this example. The depth of all channels ranges from 3-8 mm, with 5 mm used in this example. The connection angle between zero-stage channel 4, primary channel 5, secondary channel 6, and tertiary channel 7 is 90°.

[0045] The overall material of the liquid cooling plate is a metal with high thermal conductivity, usually copper or aluminum.

[0046] The liquid cooling plate is manufactured by milling the flow channels of the upper flow channel plate 1, the middle plate 2 and the lower flow channel plate 3, or by directly casting the upper flow channel plate 1, the middle plate 2 and the lower flow channel plate 3 using a lost mold process. This allows the flow channels of the liquid cooling plate to be cast in one go, saving time. The upper flow channel plate 1, the middle plate 2 and the lower flow channel plate 3 are connected and sealed by adding metal solder and brazing at high temperature, forming independent flow channels at the top and bottom and connecting them through the hollow flow channel 10 of the middle plate 2.

[0047] The working fluid is a solution of water, ethylene glycol, or a mixture of both as the cooling medium.

[0048] Furthermore, such as Figure 5 As shown, the cooling medium enters from the inlet pipe 9 of the upper flow channel plate 1, passes through the inlet hole 11 of the intermediate plate 2, and enters the zero-stage flow channel 4 of the lower flow channel plate 3. It then splits from the zero-stage flow channel 4 and enters the first-stage flow channel 5. The cooling medium in the first-stage flow channel 5 splits into the second-stage flow channel 6 and finally flows into the third-stage flow channel 7. After that, the flowing medium enters the third-stage flow channel 7 of the upper flow channel plate 1 through the hollowed-out flow channel 10 of the intermediate plate 2. Finally, it flows out from the outlet flow channel 8 in the order of the third-stage, second-stage, first-stage, and zero-stage flow channels.

[0049] To verify the optimization of the double-layer fractal flow channel liquid cooling plate to heat transfer and temperature uniformity, the scheme of the patent "Bionic liquid cooling device for lithium ion battery equalization heat dissipation" of CN219892241U is compared with the present application, as shown in Figure 6 The overall size of the cold plate of the present application is designed as a single-layer bionic vein flow channel liquid cooling plate 12 as a comparison item, the above-mentioned flow channel plate 12 includes an inlet flow channel 13, an outlet flow channel 14 and a bionic vein passage 15.

[0050] The bionic vein flow channel liquid cooling plate 12 and the double-layer flow channel liquid cooling plate of the present application are simulated by using the general commercial software ANSYS Fluent, the calculation model is a three-dimensional transient laminar incompressible model; the flow channel inlet is set as a velocity inlet, the outlet is set as a pressure outlet, the inlet temperature is 27℃, the heat dissipation surface is set as a constant heat flux density, the heat generation and heat generation time are set as battery 2C discharge, the hydraulic diameter of the unified inlet of the above-mentioned two liquid cooling plates is 16mm, and the inlet Reynolds number is unified as 500.

[0051] Under the above boundary conditions, the temperature cloud maps of the above-mentioned two liquid cooling plates are as shown in Figure 7 The high temperature positions of the two liquid cooling plates appear far away from the flow channel, the low temperature positions of the two liquid cooling plates appear in the middle of the flow channel, but the temperature of the double-layer fractal flow channel liquid cooling plate is more uniform, and the overall temperature is lower than that of the single-layer bionic vein flow channel liquid cooling plate. The highest temperature, average temperature and maximum temperature difference of the two liquid cooling plates are compared as shown in Figure 8 According to the simulation results, the surface temperature difference of the cold plate of the present application is 38% lower than that of the existing single-layer cold plate 12, the highest temperature and average temperature are also significantly lower than those of the single-layer cold plate 12, which proves that the cold plate structure of the present application can significantly improve the temperature uniformity of the heat dissipation surface.

[0052] The above-mentioned is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can obtain technical solutions, concepts and designs according to the technical scheme of the present application and the concept of the present application within the technical range disclosed by the present application, which are equivalent to the replacement or change of the present application, and should be covered within the protection scope of the present application.

Claims

1. A double-layer fractal flow channel liquid cooling plate, comprising a lower flow channel plate, an intermediate plate, and an upper flow channel plate, characterized in that: the upper surface of the lower flow channel plate is provided with a first flow channel through which fluid flows, the first flow channel comprising a lower zero-order flow channel, a lower first-order flow channel, a lower second-order flow channel, and a lower third-order flow channel; the lower zero-order flow channel comprises two parallel flow channels of different lengths arranged in the shape of a lower-case h, the shorter flow channel of the lower zero-order flow channel is connected to the length symmetry line of the longer flow channel through a vertical flow channel, the longer flow channel of the lower zero-order flow channel is connected to 2-4 parallel lower first-order flow channels, each lower first-order flow channel is connected to a plurality of parallel lower second-order flow channels on both sides, and the lower second-order flow channels are connected to lower third-order flow channels parallel to the lower first-order flow channels; the intermediate plate comprises a hollow flow channel and an inlet hole, the lower surface of the upper flow channel plate is provided with a second flow channel through which fluid flows, the second flow channel comprising an upper zero-order flow channel, an upper first-order flow channel, an upper second-order flow channel, and an upper third-order flow channel, and an inlet pipe and an outlet pipe are arranged; the upper zero-order flow channel and the lower zero-order flow channel are symmetrically distributed along the vertical flow channel, the upper first-order flow channel, the upper second-order flow channel, and the upper third-order flow channel are arranged in the same manner as the lower first-order flow channel, the lower second-order flow channel, and the lower third-order flow channel; the upper third-order flow channel is in one-to-one correspondence with the lower third-order flow channel through the hollow flow channel of the intermediate plate, the inlet pipe is connected to the shorter flow channel of the lower zero-order flow channel through the inlet hole, and the outlet pipe is connected to the shorter flow channel of the upper zero-order flow channel. the flow directions of the upper first-order flow channel and the lower first-order flow channel are opposite; 2. The dual-layer fractal flow channel liquid cooling board according to claim 1, characterized in that the fluid and / or the flow directions of the lower second-order flow channel and the upper second-order flow channel are opposite. the width of the first-order flow channel gradually decreases in the direction away from the upper zero-order flow channel; 3. The dual-layer fractal flow channel liquid cooling board according to claim 1, characterized in that the upper layer and / or the width of the lower first-order flow channel gradually decreases in the direction away from the lower zero-order flow channel; and / or the width of the upper third-order flow channel gradually decreases in the direction close to the upper zero-order flow channel; and / or the width of the lower third-order flow channel gradually decreases in the direction close to the lower zero-order flow channel; and / or the width of the hollow flow channel gradually decreases in the direction close to the lower zero-order flow channel. 4.The double-layer fractal flow channel liquid cooling plate according to claim 3, characterized in that: the width reduction ratios of the upper first-order flow channel, the lower first-order flow channel, the upper third-order flow channel, the lower third-order flow channel, and the hollow flow channel are the same, and the width reduction ratio is in the range of 0.3-0.

7. the upper zero-order flow channel of the upper flow channel plate is fractal to the 2-4 upper first-order flow channels, the upper first-order flow channel is also connected to a plurality of upper second-order flow channels on both sides in parallel, the tail of the upper second-order flow channel is connected to the upper third-order flow channel in a vertical manner, and the angle between each flow channel is 90° when they are connected to each other; and / or the lower zero-order flow channel of the lower flow channel plate is fractal to the 2-4 lower first-order flow channels, the lower first-order flow channel is also connected to a plurality of lower second-order flow channels on both sides in parallel, the tail of the lower second-order flow channel is connected to the lower third-order flow channel in a vertical manner, and the angle between each flow channel is 90° when they are connected to each other.

5. The dual-layer fractal flow channel liquid cooling board according to claim 1, characterized in that: the average width of the upper first-order flow channel is 2 times the average width of the upper third-order flow channel; and the spacing between two adjacent upper second-order flow channels is 20-40 mm. ​ 6. The dual-layer fractal flow channel liquid cooling board according to claim 1, characterized in that: ​ The average width of the lower primary flow channel is 2 times the average width of the lower tertiary flow channel; the spacing between two adjacent lower secondary flow channels is 20-40 mm. The average width of the lower primary flow channel is 2 times the average width of the lower tertiary flow channel; the spacing between two adjacent lower secondary flow channels is 20-40 mm.

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