Fish scale type lithium battery liquid cooling pipe structure

Abstract

The invention relates to the technical field of battery thermal management, in particular to a fish scale type lithium battery liquid cooling pipe structure. Comprising a liquid cooling pipe used for cooling a plurality of 18650 lithium batteries, the plurality of 18650 lithium batteries are divided into two groups of isosceles triangle battery packs and are symmetrically arranged along a central line, the liquid cooling pipe forms a plurality of fish scale-shaped spaces, the fish scale-shaped spaces form inner arc walls, each 18650 lithium battery is arranged in the fish scale-shaped space, and the inner arc walls are arranged on the outer arc walls. And therefore, the 18650 lithium battery is tightly attached to the inner arc wall of the fish scale-shaped space. The heat dissipation problem of the 18650 lithium battery in the working process is solved.

Description

Technical Field

[0001] The invention relates to the technical field of battery thermal management, and in particular to a fish-scale type lithium battery liquid cooling tube structure. Background Art

[0002] During the operation of electric vehicles, lithium-ion batteries will continuously release heat due to chemical reactions during the charging and discharging process. As time goes by, the gradual accumulation of this heat causes the battery pack temperature to rise significantly. If an effective heat dissipation mechanism is not implemented, this temperature increase will not only reduce the available capacity of the battery, but will also have a serious impact on the battery life. Excessive temperatures may even cause thermal runaway of the battery pack, which in turn may lead to liquid leakage and cause safety problems. Therefore, the design of the power battery pack heat dissipation system is a key link to ensure the normal operation of the power battery, and it is also one of the important technical challenges that need to be urgently solved in the development of new energy vehicles.

[0003] Existing battery cooling methods include air cooling, phase change material cooling, heat pipe cooling and liquid cooling. Liquid cooling tube cooling is the mainstream solution in current battery cooling technology. At present, the main research direction of power battery liquid cooling tube cooling is to improve its cooling performance by designing and optimizing the structural form of the liquid cooling tube. CN109065795A proposes a battery module liquid cooling integrated packaging structure, in which the liquid cooling tube is bent to form at least one placement groove for placing the battery, one end of the placement groove is open and the other end is closed. The placement groove and the liquid cooling tubes on both sides are used to effectively improve the cooling efficiency of the battery module. The battery, liquid cooling tube and front and rear end plates form a whole, which is simple and convenient to install. However, it is not applicable to cylindrical 18650 lithium batteries, and it is impossible to effectively control the temperature.

[0004] Therefore, it is necessary to deeply design the structure of the lithium battery liquid cooling tube to significantly reduce the maximum operating temperature of the battery while maintaining the uniformity of the overall temperature of the battery pack during operation. Summary of the invention

[0005] In order to solve the problem of heat dissipation of 18650 lithium batteries during operation, the present invention provides a fish scale type lithium battery liquid cooling tube structure.

[0006] The present invention provides a fish scale type lithium battery liquid cooling tube structure, comprising: a liquid cooling tube for cooling a plurality of 18650 lithium batteries, wherein the plurality of 18650 lithium batteries are divided into two groups of isosceles triangle battery packs and are symmetrically arranged along a center line, wherein the liquid cooling tube forms a plurality of fish scale spaces, wherein the fish scale spaces are formed with inner arc walls, and each 18650 lithium battery is placed in the fish scale space, so that the 18650 lithium battery is tightly fitted on the inner arc wall of the fish scale space.

[0007] Furthermore, there are 32 18650 lithium batteries, and the multiple 18650 lithium batteries are divided into two isosceles triangle battery groups, each isosceles triangle battery group includes 16 18650 lithium batteries, and the outer contour of the liquid cooling tube is a square.

[0008] Furthermore, the distance between the 18650 lithium batteries is 20 mm, and the distance between the two isosceles triangle battery packs is 22 mm.

[0009] Furthermore, the contact arc angle between the liquid cooling tube and the 18650 lithium battery is greater than 180°.

[0010] Furthermore, the liquid cooling tube is manufactured from aluminum material and formed in one piece. A liquid inlet and a liquid outlet are respectively provided at both ends of the liquid cooling tube. The liquid inlet and the liquid outlet are respectively provided at two bottom angles of an isosceles triangle.

[0011] Furthermore, the height of the liquid cooling tube is less than the height of a 18650 lithium battery.

[0012] Furthermore, the 18650 lithium battery is cylindrical, the height of the 18650 lithium battery is 65 mm, and the height of the liquid cooling tube is 50 mm.

[0013] Furthermore, the cross-sectional diameter of the 18650 lithium battery is 3.3 mm, and the wall thickness of the liquid cooling tube is 0.3 mm.

[0014] In summary, the present invention has the following beneficial technical effects: 1. The fish-scale lithium battery liquid cooling tube structure proposed in the present invention is suitable for 18650 lithium batteries. By structurally designing the battery liquid cooling pipe type and rationally arranging the battery module, the temperature uniformity of the battery pack is greatly improved, and the maximum temperature of the battery is significantly reduced. By reducing the wall thickness of the battery liquid cooling tube and reducing the height of the liquid cooling tube, the overall heat dissipation efficiency of the battery module is improved, and the lightweight design of new energy electric vehicles is realized.

[0015] 2. The fish-scale lithium battery liquid cooling tube structure proposed in the present invention reduces the gap between adjacent batteries by symmetrically arranging the battery pack and setting the distance between adjacent batteries, increases the overall density of the battery pack, and increases the contact area between the liquid cooling tube and the battery. Compared with battery modules without liquid cooling tubes and with Swiss roll liquid cooling tube configurations, the maximum temperature and temperature difference of the fish-scale lithium battery liquid cooling tube configuration and its battery module are significantly reduced, which well verifies the effectiveness of the proposed lithium battery liquid cooling tube structure design. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is an overall structural diagram of a fish scale type lithium battery liquid cooling tube structure of the present invention; Figure 2 It is a front view of a fish scale type lithium battery liquid cooling tube structure of the present invention; Figure 3 It is a structural schematic diagram of the liquid cooling tube of the present invention; Figure 4 is a cross-sectional view of a liquid cooling tube of the present invention; Figure 5 This is the temperature cloud diagram of the battery without liquid cooling pipeline; Figure 6 This is the battery temperature cloud diagram of the Swiss roll liquid cooling pipeline; Figure 7 This is the temperature cloud diagram of the battery with fish-scale liquid cooling pipeline; Figure 8 The temperature cloud diagram of lithium battery with fish scale liquid cooling tubes of different heights; Fig. 9 It is a schematic diagram of the structure of a Swiss roll liquid cooling tube in the prior art. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0018] Example 1 Reference Figure 1 and Figure 2 , a fish-scale lithium battery liquid cooling pipe structure of this embodiment includes: a liquid cooling pipe 2 for cooling multiple 18650 lithium batteries 1, two curved groove-type liquid cooling pipes with rectangular cross-sections, which can not only significantly reduce the maximum operating temperature of the battery, but also maintain the overall temperature uniformity of the battery pack when the battery is working. The battery liquid cooling pipeline structure as a whole presents a folded and symmetrical arrangement. The pipeline includes a liquid inlet and a liquid outlet, which enters the battery pack from the left side of the center of the battery pack. The coolant diverges in the battery pack in the shape of fish scales and winds through each battery, and flows out on the other side of the battery pack. The battery module of the 18650 lithium battery is composed of 32 18650 batteries, two groups of four rows and seven columns of isosceles triangles, which are symmetrically arranged. The contact area between the 18650 lithium battery and the liquid cooling pipeline is increased, which increases the heat exchange efficiency between the battery and the liquid cooling pipe, and makes the battery pack temperature more uniform.

[0019] Combination Figure 3 and Figure 4 As shown, both ends of each fish-scale lithium battery liquid cooling tube are the inlet and outlet of the coolant. The liquid cooling tube is formed as a whole in a continuous and closed manner. The coolant flows into the fish-scale liquid cooling tube from the water inlet, flows through each single battery in the liquid cooling tube, and then flows out from the water outlet to achieve uniform cooling of the battery pack temperature and increase the battery life.

[0020] Reference Figure 3 , Figure 4 and Figure 5 The battery module is formed by symmetrically arranging two groups of 18650 lithium batteries in four rows and seven columns of isosceles triangles, wherein in each group of four rows and seven columns of isosceles triangles, the distance between each row of batteries is 20 mm, and the distance between each column of batteries is also 20 mm. The symmetrical arrangement of the two groups of battery packs is based on the longest side of the triangle, and the two longest sides are 4 mm apart, so as to construct a battery module that closely matches the fish scale type lithium battery liquid cooling tube. The distance between the two groups of isosceles triangle battery packs is 22 mm, which can accommodate two liquid cooling tubes passing through the battery pack.

[0021] The fish-scale lithium battery liquid cooling pipeline is made of aluminum alloy, which can better transfer heat and conduct heat. The battery liquid cooling pipeline is tightly wrapped around the cylindrical lithium battery, directly exchanging heat with the battery. The battery liquid cooling pipeline configuration is wound so that the cooling pipeline adopts multiple paths to enter the center of the battery pack where heat dissipation is most difficult. The low-temperature cooling that has just entered the liquid cooling pipeline is used to directly cool the center of the battery pack along the alignment line, and then the fish-scale battery liquid cooling pipeline is radiated to wrap the entire battery module, greatly increasing the contact area with the lithium battery, so that the lithium battery module as a whole can achieve a more uniform temperature. Fig. 9 ,Structural diagram of Swiss roll cooling tube,Through comparative experiments, refer to Figure 5 , Figure 6 and Figure 7 As shown in the figure, compared with the battery module without liquid cooling tube and with Swiss roll liquid cooling tube 3 configuration, the maximum temperature of the fish scale type lithium battery liquid cooling tube configuration and its battery module decreased by 115.8 K and 3.3 K respectively, and the maximum temperature difference also decreased by 22 K and 2.3 K respectively. The overall height of the fish scale type liquid cooling tube is 5 mm lower than that of the Swiss roll liquid cooling tube 3. The above results verify the effectiveness of the structural design of the proposed lithium battery liquid cooling tube.

[0022] In order to reduce the overall weight of the battery module and achieve the goal of lightweight design of the vehicle, the liquid cooling pipe is designed to be 50 mm, which is 15 mm lower than the height of the battery liquid cooling pipe at the same height as the battery. This makes the entire module lightweight while meeting the cooling performance. The wall thickness of the cooling pipe is set to 0.3 mm. Under the premise that the liquid pressure can be met, the thinner wall thickness can improve the heat exchange efficiency between the battery liquid cooling pipe and the battery. After comprehensive comparison, it is found that the 50 mm high battery liquid cooling pipe can better achieve the overall lightweight design of the battery module while keeping the maximum temperature and temperature difference of the battery module unchanged. Figure 8, where (a) to (e) are the heights of the liquid cooling tubes 40 mm, 45 mm, 50 mm, 55 mm, and 60 mm respectively. It can be found that the battery pack temperature does not always decrease when only the height of the liquid cooling tube is increased. After comprehensive comparison, it is found that the battery liquid cooling tube with a height of 50 mm can better achieve the overall lightweight design of the battery module while keeping the maximum temperature and temperature difference of the battery module unchanged.

[0023] The material used to manufacture battery liquid cooling tubes is aluminum alloy. Aluminum alloy has the advantages of high strength, good corrosion resistance, good processing performance and easy regeneration. It also has good thermal conductivity and a wide range of applications.

[0024] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The present invention provides a fish scale type lithium battery liquid cooling tube structure, characterized in that: It includes a liquid cooling tube for cooling a plurality of 18650 lithium batteries. The plurality of 18650 lithium batteries are divided into two battery groups in the form of isosceles triangles and are arranged symmetrically along a center line. The liquid cooling tube forms a plurality of fish scale-shaped spaces. The outer contour of the liquid cooling tube is a square. The fish scale-shaped spaces are formed with inner arc walls. Each 18650 lithium battery is placed in the fish scale-shaped space, so that the 18650 lithium battery fits tightly on the inner arc wall of the fish scale-shaped space.

2. The fish scale type lithium battery liquid cooling tube structure according to claim 1, characterized in that: There are 32 18650 lithium batteries, and the multiple 18650 lithium batteries are divided into two isosceles triangle battery groups, and each isosceles triangle battery group includes 16 18650 lithium batteries.

3. The fish scale type lithium battery liquid cooling tube structure according to claim 1, characterized in that: The distance between the 18650 lithium batteries is 20 mm, and the distance between the two isosceles triangle battery packs is 22 mm.

4. The fish scale type lithium battery liquid cooling tube structure according to claim 3, characterized in that: The contact arc angle between the liquid cooling tube and the 18650 lithium battery is greater than 180°.

5. The fish scale type lithium battery liquid cooling tube structure according to claim 4, characterized in that: The liquid cooling tube is made of aluminum material and formed in one piece. A liquid inlet and a liquid outlet are respectively arranged at two ends of the liquid cooling tube. The liquid inlet and the liquid outlet are respectively arranged at two bottom angles of an isosceles triangle.

6. The fish scale type lithium battery liquid cooling tube structure according to claim 5, characterized in that: The height of the liquid cooling tube is less than that of a 18650 lithium battery.

7. The fish scale type lithium battery liquid cooling tube structure according to claim 6, characterized in that: The 18650 lithium battery is cylindrical, the height of the 18650 lithium battery is 65 mm, and the height of the liquid cooling tube is 50 mm.

8. The fish scale type lithium battery liquid cooling tube structure according to claim 7, characterized in that: The cross-sectional diameter of the 18650 lithium battery is 3.3 mm, and the wall thickness of the liquid cooling tube is 0.3 mm.

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