Shunting snakelike liquid cooling system for new energy automobile lithium battery

Abstract

The invention discloses a shunting snakelike liquid cooling system for a new energy automobile lithium battery, which belongs to the technical field of lithium battery liquid cooling and comprises a shunting snakelike liquid cooling plate provided with an inlet, an outlet and a plurality of shunting channels. After entering from the inlet, cooling liquid firstly cools a high-temperature area in the center of the battery in a centralized manner and then cools other parts in a split-flow manner, so that the temperature distribution uniformity of the battery is effectively improved, and the pressure drop is reduced. According to the system, an aluminum alloy liquid cooling plate is adopted, an ethylene glycol solution with the concentration of 50% is preferably selected as cooling liquid, the initial temperature is 25 DEG C, the flow velocity is 0.05 m / s, the highest and lowest temperature difference of the battery is smaller than 2 DEG C, and the pressure drop is smaller than 200 Pa. The flow channel structure is optimized on the basis of a traditional snake-shaped liquid cooling plate, heat dissipation efficiency and energy consumption control are both considered, and the snake-shaped liquid cooling plate is suitable for heat management of high-energy-density equipment such as new energy automobiles and energy storage systems.

Description

Technical Field

[0001] This invention relates to the field of lithium battery liquid cooling technology, and in particular to a shunt serpentine liquid cooling system for lithium batteries in new energy vehicles. Background Technology

[0002] With the rapid development of industries such as new energy vehicles, mobile devices, and energy storage systems, lithium batteries, as a high-efficiency and renewable energy storage device, are seeing their application scope continuously expand and demand surge. Simultaneously, with the rapid advancement of technology, the energy density and power output of batteries have significantly increased, making thermal management issues increasingly prominent and becoming one of the key factors affecting battery performance and safety. Compared to air cooling's poor performance in high ambient temperatures and extreme conditions, and the current difficulty in large-scale commercial application of phase change materials, liquid cooling, due to its more mature technology, higher thermal conductivity, and better heat capacity, is increasingly being used in scenarios with high heat dissipation requirements. Current liquid cooling primarily uses serpentine cooling plates to cool lithium batteries; however, traditional serpentine liquid cooling plates suffer from uneven temperature distribution.

[0003] Therefore, there is an urgent need in this field for a technical solution that can solve the problem of uneven temperature distribution in traditional serpentine liquid cooling plates.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a technical solution to address the problem of uneven temperature distribution in traditional serpentine liquid cooling plates. Starting from the heat generation and heat transfer mechanisms of lithium batteries, this invention uses SOLIDWORKS for three-dimensional modeling and Fluent fluid simulation technology to construct a simplified heat generation rate model and calculate relevant thermophysical parameters. Through in-depth analysis of data from references, a UDF function is written to construct a single-cell heat generation model. Simulations are performed under 2C discharge rate conditions, and the results are compared and verified with experimental results. The heat dissipation of the battery after adding a liquid cooling plate is further studied, and a convection serpentine liquid cooling plate is designed. Its parameters are adjusted and optimized from multiple aspects to improve its cooling efficiency. Focusing on the temperature and flow rate of the coolant, the optimal temperature and flow rate range is determined through scientific experiments and data analysis, thereby perfecting the liquid cooling heat dissipation system.

[0006] To achieve the above objectives, the present invention provides the following solution: A shunt serpentine liquid cooling system for lithium batteries in new energy vehicles includes: a shunt serpentine liquid cooling plate having an inlet, an outlet, and multiple shunt channels. The shunt channels are configured such that after the coolant enters from the inlet, it first cools the high-temperature area in the center of the battery, and then shunts to cool other parts of the battery, thereby improving the uniformity of the battery's temperature distribution and reducing the voltage drop.

[0007] Optionally, the dimensions of the diversion serpentine liquid cooling plate are 148mm × 91mm × 4mm.

[0008] Optionally, the dimensions of the diversion channel are 6mm in length and 2mm in width.

[0009] Optionally, the material of the diversion serpentine liquid cooling plate is aluminum alloy.

[0010] Optionally, the coolant is a 50% ethylene glycol solution with a density of 1071.1 kg / m³.

[0011] Optionally, the flow rate of the coolant in the distribution channel is 0.05 m / s.

[0012] Optionally, the initial temperature of the coolant is 25°C.

[0013] Optionally, the pressure drop from the inlet to the outlet of the diversion serpentine liquid cooling plate is less than 200 Pa.

[0014] Optionally, the system ensures that the temperature difference between the battery's highest and lowest temperatures is less than 2°C.

[0015] Optionally, the system can be applied to battery thermal management, energy storage systems, or high-energy-density mobile devices in new energy vehicles.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a shunt serpentine liquid cooling system for lithium batteries in new energy vehicles. Based on the traditional serpentine liquid cooling plate, a novel liquid cooling plate structure is innovatively designed. Various factors affecting heat dissipation were studied and optimized to improve cooling efficiency. Simultaneously, different temperatures and flow rates of the coolant were tested. Through scientific experiments and data analysis, the optimal temperature and flow rate range was determined, ensuring the liquid cooling system can perform at its best, effectively extending battery life and improving the overall system performance and safety. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of a flow-diverting serpentine liquid cooling plate provided in an embodiment of the present invention.

[0019] Figure 2 Temperature diagrams at different flow rates are provided for embodiments of the present invention.

[0020] Figure 3 Pressure drop diagrams at different flow rates are provided for embodiments of the present invention.

[0021] Figure 4 The temperature simulation diagram of a conventional liquid cooling plate is provided for an embodiment of the present invention.

[0022] Figure 5 Temperature simulation diagram of the shunt serpentine liquid cooling plate provided in the embodiment of the present invention.

[0023] Figure 6 A cloud diagram illustrating the heating effect of a lithium battery provided in an embodiment of the present invention.

[0024] Figure 7 Temperature diagrams at different flow rates are provided for embodiments of the present invention.

[0025] Figure 8 Pressure drop diagrams at different flow rates are provided for embodiments of the present invention.

[0026] Figure 9 The temperature distribution cloud maps of different materials provided in the embodiments of the present invention are as follows: (1) is the temperature distribution cloud map of aluminum liquid cooling plate, (2) is the temperature distribution cloud map of copper liquid cooling plate, (3) is the temperature distribution cloud map of iron liquid cooling plate, and (4) is the temperature distribution cloud map of aluminum alloy liquid cooling plate.

[0027] Figure 10 The battery temperature distribution cloud map under different coolant temperatures is provided for the embodiments of the present invention.

[0028] Figure 11 This is a schematic diagram illustrating the effect of different flow channel widths on temperature and pressure drop, provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The purpose of this invention is to provide a technical solution that can solve the problem of uneven temperature distribution in traditional serpentine liquid cooling plates.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1: This embodiment provides a shunt serpentine liquid cooling system for lithium batteries in new energy vehicles. A shunt serpentine cooling plate with dimensions of 148*91*4mm (length*width*thickness) was designed using SOLIDWORKS software. The cooling channels are designed to be 6mm long and 2mm wide (e.g.,...). Figure 1 As shown in the image, based on market research data, a 50% ethylene glycol solution with a solution density of 1071.1 kg / m³ is selected as the coolant. 3 .

[0033] Taking into account factors such as heat dissipation requirements, cost budget, weight requirements, and processing technology, aluminum alloy was selected as the material for the liquid cooling plate. Studies on the different cooling effects produced by the coolant at different temperatures were conducted, and 25℃ was adopted as the initial coolant temperature. Specific research data are shown in Table 1. Figure 2 and Figure 3 : Table 1

[0034] In the simulation studying the effect of flow rate on battery temperature and pressure drop at the inlet and outlet of the liquid coolant plate, the temperature and pressure distribution diagrams of the coolant at flow rates of 0.05 m / s, 0.1 m / s, 0.5 m / s, and 0.7 m / s are shown below. Considering all factors, a coolant flow rate of 0.05 m / s is the most suitable.

[0035] When investigating the cooling effects of innovative and traditional battery cooling systems, other conditions were kept constant, with the ambient temperature and initial coolant temperature both set at 25℃, and the flow rate set at 0.05 m / s. Simulated cloud map data showed that under the traditional serpentine cooling plate, the battery's highest temperature was 29.32℃, the lowest temperature was 26.89℃, and the temperature difference was 2.43℃; under the shunt serpentine cooling plate, the highest temperature was 29.06℃, the lowest temperature was 27.53℃, and the temperature difference was 1.53℃. This leads to the conclusion that the shunt serpentine liquid cooling plate has a significantly stronger cooling effect than the traditional liquid cooling plate. Figure 4 and Figure 5 As shown.

[0036] Regarding the impact of voltage drop on the efficiency of the battery thermal management system, the voltage drop from the inlet to the outlet of the traditional serpentine liquid cooling plate is 349 Pa, while the voltage drop of the designed shunt serpentine liquid cooling plate is 179 Pa. Since the voltage drop is smaller, the system energy consumption can be reduced, so the shunt serpentine liquid cooling plate is more in line with market demand.

[0037] The battery studied in this embodiment is a 40Ah ternary square lithium-ion battery with dimensions of 148*27*91mm (length*width*height). Analysis of the simulation results revealed that the battery's temperature distribution cloud map shows a higher temperature at the center, gradually decreasing towards the edges. Figure 6 As shown, we plan to place the battery between the liquid cooling plates and select a repeating unit as the research object.

[0038] The liquid cooling plate designed in this embodiment has dimensions of 148*91*4mm (length*width*height), and the cooling channel is designed to be 6mm long and 2mm wide.

[0039] The shunt serpentine liquid cooling plate is an innovative design based on the traditional serpentine liquid cooling plate. Its working principle primarily involves optimizing the flow channel structure so that the coolant, after entering from the inlet, first cools the high-temperature central area of ​​the battery, and then is diverted to cool other parts of the battery. This design utilizes a 50% concentration ethylene glycol solution as the cooling medium, which flows through channels close to the battery module under the drive of a circulating pump. Through convection, it absorbs the heat generated by the battery. The cooled liquid then flows to an external radiator, where it exchanges heat with the outside air to release heat, lowering its temperature before circulating back to the battery to continue absorbing heat. Compared to traditional serpentine liquid cooling plates, the shunt design disperses the coolant flow, reducing the flow rate and velocity entering each sub-channel. This improves temperature uniformity and reduces battery temperature differences while lowering the inlet and outlet pressure drop, thereby reducing system energy consumption while maintaining cooling effectiveness.

[0040] In the study of coolant flow rate in the shunt serpentine liquid cooling plate, 0.05 m / s was selected. Compared with other flow rates such as 0.1 m / s, 0.3 m / s, 0.5 m / s, and 0.7 m / s, this flow rate places the battery's highest temperature within its optimal operating range, meeting cooling requirements. Simultaneously, the corresponding inlet and outlet pressure drop of the liquid cooling plate is optimal, significantly lower than the pressure drop at higher flow rates, which can significantly reduce system energy consumption. This achieves effective energy control while ensuring cooling performance, making it a better choice that balances cooling performance and energy consumption. Figure 7 and Figure 8 As shown.

[0041] In the selection of materials for the shunt serpentine liquid cooling plate, aluminum alloy was ultimately chosen. Aluminum alloy possesses excellent thermal conductivity, enabling efficient transfer of heat generated by the battery to meet the heat dissipation requirements of the liquid cooling system. Its lightweight nature, significantly lower than iron and copper, does not increase the overall burden on the battery module, helping to control energy consumption in applications such as new energy vehicles. In terms of cost, aluminum alloy is more economical than copper, reducing the manufacturing cost of the liquid cooling plate and making it suitable for large-scale applications. Furthermore, through alloying treatment, the mechanical strength and corrosion resistance of aluminum alloy are significantly improved, allowing it to adapt to complex working environments and extending the service life of the liquid cooling plate. While ensuring heat dissipation efficiency, it also considers practicality, economy, and reliability, making it an ideal material choice for liquid cooling plates.

[0042] In selecting the coolant temperature for the shunt serpentine liquid cooling plate, an initial temperature of 25℃ is used. At this temperature, the battery's highest temperature is within its optimal operating range, with a small temperature difference, ensuring stable battery performance and safety. Compared to coolants of 15℃ and 20℃, 25℃ requires no additional cooling energy and can be achieved directly using ambient temperature, making it easier to operate. Compared to coolants of 30℃ and 35℃, at 25℃, the battery temperature is further from the safe upper limit, providing a more ample safety margin, and requires no additional heating energy. While meeting heat dissipation requirements, it also balances system energy consumption and practicality, making it a superior choice overall. Figure 10 As shown.

[0043] In the selection of the flow channel width for the shunt serpentine liquid cooling plate, it was studied that when the flow channel width increased from 4 mm to 10 mm, the maximum battery temperature only decreased from 29.99℃ to 29.89℃, a reduction of 0.1℃. This is because although the increased flow channel width expands the contact area, it reduces the flow velocity, resulting in a weak overall cooling effect. However, the pressure drop at the inlet and outlet of the liquid cooling plate significantly decreased from 316.79 Pa to 90.94 Pa, a reduction of 71.3%. This is due to the increased flow channel cross-sectional area, which reduces the flow velocity, decreases the Reynolds number, and reduces friction loss and local resistance. In summary, the flow channel width has a negligible impact on the maximum battery temperature but can significantly reduce system pump power consumption. In practical applications, it is recommended to select a suitable flow channel width to balance heat dissipation performance and energy consumption.

[0044] Employing highly efficient liquid circulation cooling technology, it boasts higher thermal conductivity and better heat capacity, precisely controlling the temperature of each battery cell to prevent thermal runaway, significantly enhancing battery system safety and extending battery life. The following is a comparison of different cooling technologies for similar batteries.

[0045] Table 2 Advantages and disadvantages of different cooling methods

[0046] It is evident that liquid cooling technology possesses excellent heat transfer and dissipation capabilities, and boasts advantages such as relatively mature development and superior performance.

[0047] By comparing the thermophysical properties of aluminum, copper, iron, and aluminum alloys, the highest battery temperatures were 29.06℃, 29.01℃, 29.08℃, and 29.06℃ respectively when the cooling plate material was aluminum, copper, iron, and aluminum alloy. Copper exhibited the best heat dissipation, but it was expensive and heavy. Iron, due to its relatively low thermal conductivity, had poor heat dissipation; its hardness and cost-effectiveness, rather than its heat dissipation performance, made it less than the optimal heat transfer material, and its weight made it unsuitable for applications requiring lightweight construction. Aluminum alloys, through alloying, can maintain aluminum's lightweight and easy-to-process characteristics while improving its mechanical properties and corrosion resistance. When selecting a liquid cooling plate material, factors such as heat dissipation requirements, cost budget, weight requirements, and processing technology need to be comprehensively considered. The conclusion is that aluminum alloy is the optimal cooling plate material.

[0048] Table 3. Material thermophysical properties

[0049] This embodiment innovatively changes the "S"-shaped flow channel of the traditional serpentine condenser plate to a split flow channel, which solves the problem of uneven heat distribution in the battery after heat dissipation and improves heat dissipation efficiency.

[0050] The innovative design features an excellent flow channel width, ensuring superior heat dissipation performance while effectively improving the cooling efficiency and energy saving of the liquid cooling plate.

[0051] The flow rate of coolant affects temperature and pressure drop, thus increasing energy consumption. Therefore, an innovative design was developed to achieve a suitable flow rate, balancing cooling efficiency and energy consumption.

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0053] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A shunt serpentine liquid cooling system for new energy vehicle lithium batteries, characterized in that, The system includes a shunt serpentine liquid cooling plate having an inlet, an outlet, and a plurality of shunt channels configured to cause the cooling liquid to enter from the inlet, first cool a center high temperature area of the battery, and then shunt to cool other parts of the battery, thereby improving temperature distribution uniformity of the battery and reducing pressure drop.

2. The split serpentine liquid cooling system of claim 1, wherein, The size of the shunt serpentine liquid cooling plate is 148mm x 91mm x 4mm.

3. The split serpentine liquid cooling system of claim 1, wherein, The size of the shunt channel is 6mm long and 2mm wide.

4. The split serpentine liquid cooling system of claim 1, wherein, The material of the shunt serpentine liquid cooling plate is aluminum alloy.

5. The split serpentine liquid cooling system of claim 1, wherein, The coolant is a 50% concentration of ethylene glycol solution, and its density is 1071.1 kg / m 3 .

6. The split serpentine liquid cooling system of claim 1, wherein, The flow rate of the cooling liquid in the shunt channel is 0.05m / s.

7. The split serpentine liquid cooling system of claim 1, wherein, The initial temperature of the cooling liquid is 25℃.

8. The split serpentine liquid cooling system of claim 1, wherein, The pressure drop from the inlet to the outlet of the shunt serpentine liquid cooling plate is less than 200Pa.

9. The split serpentine liquid cooling system of claim 1, wherein, The system makes the temperature difference between the highest temperature and the lowest temperature of the battery less than 2℃.

10. The split serpentine liquid cooling system of claim 1, wherein, The system is applied to battery thermal management of new energy vehicles, energy storage systems, or high energy density mobile devices.

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