Dual-channel snakelike cold plate coupled phase change material battery thermal management system

Abstract

The invention discloses a dual-channel snakelike cold plate coupled phase change material battery thermal management system, which comprises a plurality of batteries, a dual-channel snakelike liquid cooling plate and a phase change material, two snakelike channels are arranged in the liquid cooling plate, and the flowing directions of fluids in the two snakelike channels are opposite; a secondary flow channel is arranged between every two adjacent straight flow channels of the same serpentine channel, the tops or the bottoms of the batteries are tightly attached to the liquid cooling plate, the batteries are arranged into a plurality of rows one by one in the direction of the straight flow channels in the liquid cooling plate, a gap between every two adjacent batteries in each row is filled with a phase change material, and the thickness of the phase change material between every two adjacent batteries is non-uniform. The dual-channel snakelike cold plate coupled phase change material battery thermal management system has relatively low battery pack temperature difference and relatively small cold plate inlet and outlet pressure drop at the same time.

Description

Technical Field

[0001] This invention belongs to the field of power battery thermal management, and specifically relates to a coupled battery thermal management system. Background Technology

[0002] With the deepening of the global energy transition and the "dual-carbon" goal, new energy vehicles, with their core advantages of low emissions and high efficiency, have become the core direction for the transformation and upgrading of the automotive industry, and their market penetration rate is continuing to increase rapidly. Lithium-ion batteries, due to their outstanding advantages such as high energy density, excellent power characteristics, low self-discharge rate, long cycle life, and environmental friendliness, have naturally become the mainstream choice for electric vehicle power batteries, widely used in passenger cars, commercial vehicles, new energy construction machinery, and many other fields. However, the electrochemical performance, safety stability, and lifespan of lithium-ion batteries are extremely sensitive to operating temperature, with their suitable operating temperature range typically between 20 and 40°C. If the battery is exposed to extreme temperature environments during charging and discharging, or if the large amount of heat generated cannot be dissipated in time, a series of serious problems will occur. When the temperature is too high, side reactions accelerate inside the lithium-ion battery, and the electrolyte is prone to decomposition. This not only leads to rapid capacity decay and a significant decrease in charge and discharge efficiency, but may also trigger thermal runaway, causing safety accidents such as fires and explosions. Conversely, when the temperature is too low, the ion conduction rate of the battery decreases significantly, and polarization intensifies. This not only limits charge and discharge power but may also cause lithium deposition, resulting in irreversible damage to the battery structure. Furthermore, temperature unevenness within the battery pack is also a key factor restricting battery performance. If the temperature difference between individual cells exceeds 5°C, it will lead to inconsistent depths of charge and discharge, thereby accelerating uniform battery degradation and severely shortening the lifespan of the entire battery pack. This places stringent requirements on the temperature control accuracy and temperature uniformity of the power battery thermal management system.

[0003] Among numerous battery thermal management technologies, liquid cooling technology has become the mainstream thermal management solution for mid-to-high-end new energy vehicles due to its advantages such as high heat exchange efficiency, stable temperature control, and adaptability to high-rate discharge scenarios. Among these, the serpentine cold plate, with its compact flow channel layout, high fit with the battery pack, and high space utilization, can achieve comprehensive cooling of the battery and is widely used in various power battery packs. However, traditional single-channel serpentine cold plates have revealed several insurmountable defects in practical applications: Firstly, the single-channel structure results in an excessively long flow path for the cooling fluid within the channel, leading to significant frictional losses and a substantial increase in the pressure difference between the inlet and outlet of the cold plate. This not only requires a more powerful circulating pump, increasing system energy consumption and operating costs, but may also affect the cooling effect due to uneven flow distribution. Secondly, the fluid within the single channel undergoes a continuous heat absorption process from inlet to outlet, gradually increasing the temperature. This results in a significant difference in heat exchange efficiency between the front and rear ends of the cold plate, leading to a severe temperature gradient in the battery pack. Batteries closer to the cold plate outlet are often at higher operating temperatures, exacerbating the uniform degradation of the battery pack.

[0004] To address the issue of excessive pressure drop in single-channel serpentine cold plates, industry scholars have conducted extensive targeted research. Among these studies, adding a secondary flow channel to the serpentine flow channel has emerged as a highly promising optimization direction. The secondary flow channel provides a shortcut for the fluid, allowing some fluid to bypass the lengthy serpentine path and directly cross from the upstream direct flow channel to the downstream direct flow channel, thereby effectively shortening the flow path and reducing frictional resistance. For example, Liu et al. (Huaqiang L, Xiangcheng G, Jiyun Z, et al. Liquid-based battery thermal management system performance improvement with intersected serpentine channels[J]. Renewable Energy, 2022, 199: 640-652.) integrated secondary channels into the traditional serpentine channel and applied it to a prismatic lithium-ion battery liquid thermal management system. Numerical simulation results showed that, while ensuring certain thermal performance, the addition of secondary channels significantly reduced pumping power and improved the overall operating efficiency of the system. Fan et al. (Liyun F, Jingxue L, Ya C, et al. Study on the cooling performance of a new secondary flow serpentine liquid cooling plate used for lithium battery thermal management[J]. International Journal of Heat and MassTransfer (2024, 218) designed a structure combining unidirectional secondary channels and grooves based on the traditional serpentine liquid cooling plate, and compared three different forms of serpentine cooling plates for battery modules. Experimental results showed that the cooling plate using the combination of elliptical grooves and secondary channels performed best. Although its thermal performance decreased slightly, compared with the original cooling plate, pump power consumption was significantly reduced by 92.6%, and the cooling efficiency coefficient was increased by 12.32 times, fully verifying the significant effect of secondary channels in reducing system energy consumption. However, existing serpentine cooling plate technology with secondary channels still has obvious limitations. Research has found that the opening of secondary channels disrupts the integrity and flow stability of the fluid within the channel, leading to a reduction in local heat exchange area. Simultaneously, eddies are easily generated at the intersection of the secondary channel and the main channel, which not only creates local hot spots but also increases the maximum temperature of the battery pack and exacerbates the temperature non-uniformity within the battery pack. This contradiction of "voltage reduction and temperature difference" severely restricts the further promotion and application of secondary channel serpentine cooling plate technology.

[0005] Meanwhile, phase change materials (PCMs), as a novel energy storage material, can absorb or release a large amount of latent heat during phase change while maintaining a relatively constant temperature. They offer advantages such as stable temperature regulation and the absence of external power, and are often used in coupling with liquid cooling systems to improve the temperature control performance of thermal management systems. However, existing coupling systems mostly employ a uniform filling method for PCMs, failing to specifically design them to take into account the flow characteristics and temperature distribution patterns of the liquid cooling plate. This results in the PCM's heat storage potential not being fully realized, and it is difficult to effectively solve the problem of increased temperature difference caused by secondary flow channels.

[0006] In summary, the current field of power battery thermal management urgently needs a new thermal management system that can balance low inlet and outlet voltage drop, low battery pack temperature difference, and high temperature uniformity. This system would address issues such as high energy consumption of traditional single-channel cold plates, large temperature difference of cold plates with secondary flow channels, and insufficient optimization of existing coupling systems, thereby meeting the increasingly stringent performance requirements of new energy vehicles for power battery thermal management systems. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a dual-channel serpentine liquid cooling plate coupled with a phase change material battery thermal management system. This system employs a dual-channel serpentine liquid cooling plate with a secondary flow channel added within it, and then couples it with a phase change cooling system. The aim is to solve the problems of large temperature differences in the battery pack and large pressure drops at the inlet and outlet of the cold plate caused by traditional single-channel serpentine liquid cooling plates in battery thermal management applications.

[0008] The present invention is achieved by at least one of the following technical solutions.

[0009] A dual-channel serpentine cold plate coupled phase change material thermal management system includes several batteries, a liquid cooling plate, and a phase change material; the top or bottom of each battery is tightly attached to the cold plate, the several batteries are arranged along the inner DC channel direction of the liquid cooling plate, and the phase change material is filled between adjacent batteries.

[0010] Furthermore, the liquid cooling plate includes a metal substrate and a metal cover plate, with multiple grooves on the metal substrate serving as channels for fluid flow.

[0011] Furthermore, the liquid cooling plate includes multiple inlet sections, multiple outlet sections, several direct current channels, and several semi-circular curved flow channels, forming a multi-channel liquid cooling plate, with each flow channel being a serpentine flow channel.

[0012] Furthermore, the liquid cooling plate is a dual-channel system, with the fluids flowing in opposite directions within the dual channels, forming a counter-current flow.

[0013] Furthermore, multiple secondary channels are set between the direct current channels in each serpentine flow channel.

[0014] Furthermore, the battery is a prismatic or cylindrical battery.

[0015] Furthermore, the batteries are arranged one or more rows along the DC channel direction in the liquid cooling plate.

[0016] Furthermore, phase change material is filled between the two cells in each row.

[0017] Furthermore, the phase change material is non-uniformly distributed between every two cells, with less phase change material near the cell closer to the cold plate inlet than near the cell farther from the cold plate inlet.

[0018] Furthermore, several batteries are assembled into a battery pack, with a liquid cooling plate attached to the side of the battery pack.

[0019] Compared with existing technologies, the present invention has the following advantages: 1. The dual-channel serpentine cold plate coupled phase change material battery thermal management system proposed in this invention contains two adjacent serpentine flow channels in the serpentine cold plate of the system. The fluid flow directions in the two serpentine flow channels are opposite, forming counterflow. The upstream and downstream of the two serpentine flow channels complement each other, thereby significantly reducing the temperature difference of the battery pack.

[0020] 2. The dual-channel serpentine cold plate coupled phase change material battery thermal management system proposed in this invention has a secondary flow channel set between two adjacent direct current channels in the same serpentine flow channel of the serpentine cold plate. Part of the fluid in the cold plate can directly enter the downstream through the secondary flow channel, which significantly reduces the inlet and outlet pressure drop of the cold plate, thereby reducing the energy consumption of the system.

[0021] 3. The dual-channel serpentine cold plate coupled phase change material battery thermal management system proposed in this invention fills the space between adjacent batteries with phase change material. There is less phase change material near the battery near the cold plate inlet and more phase change material near the battery away from the cold plate inlet, which further reduces the temperature difference of the battery pack and improves the temperature uniformity.

[0022] 3. The dual-channel serpentine cold plate coupled phase change material battery thermal management system proposed in this invention has the advantages of compact structure, good temperature uniformity, and energy saving, and can be widely used in the field of battery thermal management. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the coupling system in an embodiment.

[0024] Figure 2 This is a schematic diagram of the metal cover plate in an embodiment.

[0025] Figure 3 This is a comparison chart of the average temperature of the single-channel system and the dual-channel system in Example 1.

[0026] Figure 4 This is a comparison chart of the average temperature of the single-channel system and the dual-channel system in Example 2.

[0027] Figure 5 This is a comparison chart of the average temperature of the single-channel system and the dual-channel system in Example 3.

[0028] Among them, 1-liquid cooling plate, 2-phase change material, 3-battery, 4-secondary flow channel, 5-direct flow channel, 6-bent flow channel, 7-inlet section, 8-outlet section, 9-metal substrate, 10-metal cover plate. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Example 1 This embodiment provides a phase change material coupled liquid-cooled battery thermal management system, such as... Figure 1 As shown, the system includes several batteries 3, a liquid cooling plate 1, and a phase change material 2. Each battery is tightly fitted to the cooling plate at its top or bottom. The batteries are arranged in one or more rows along the inner DC channel direction of the liquid cooling plate, with the phase change material 2 filling the spaces between adjacent batteries. The liquid cooling plate includes a metal substrate 9 and a metal cover plate 10. The metal substrate 9 has multiple grooves serving as channels for fluid flow. The metal substrate 9 and the metal cover plate 10 are combined to form the liquid cooling plate. Figure 2 As shown.

[0031] The liquid cooling plate 1 includes multiple inlet sections 7, multiple outlet sections 8, several direct-flow channels 5, and several semi-circular curved flow channels 6, forming a dual-flow channel liquid cooling plate, with each flow channel being a serpentine flow channel. The fluid flow directions of the two flow channels are opposite. Multiple secondary flow channels 4 are arranged between the direct-flow channels in each serpentine flow channel. The number and width of the secondary flow channels 4 are variable, and the distribution of the secondary flow channels can be uniform or non-uniform.

[0032] In this embodiment, the battery consists of 8×2 prismatic cells. Phase change material 2 is filled between two cells 3, and the liquid cooling plate 1 is tightly bonded to the cells 3 and the phase change material 2. The cells are arranged in one or more rows along the DC channel direction in the cold plate. Phase change material is filled between two cells in each row, but not between rows. Several cells 3 form a battery pack, and the liquid cooling plate is attached to one side of the battery pack. The phase change material is non-uniformly distributed between every two cells, with less phase change material near the cells near the cold plate inlet and more phase change material near the cells further away from the cold plate inlet.

[0033] As another embodiment, two liquid cooling plates can be used, with one liquid cooling plate attached to each of the upper and lower sides of the battery pack.

[0034] The battery in this embodiment has dimensions of 90 mm × 65 mm × 18 mm, a specific heat capacity of 950 J / (kg·K), and a density of 2335 kg / m³. 3 The thermal conductivity is anisotropic, with values ​​of 1.05 W / (m·K), 21.1 W / (m·K), and 21.1 W / (m·K) in the three directions, respectively. The battery discharge rate is 5C, and the heat generation in the battery region is calculated using the Bernardi model. This model comprehensively considers both the irreversible Joule heating generated by current flowing through the internal resistance and the reversible reaction heat caused by the entropy change of the electrochemical reaction. The model is as follows:

[0035] In the formula, I This is the discharge current. R It is the equivalent resistance of the battery when discharged at a constant rate of 5C. V b It refers to the battery's volume. T b It is the temperature of the battery, coefficient d u / d T The value was obtained by electrochemical calorimetry and was -0.22 mV / K.

[0036] The liquid cooling plate 1 is made of aluminum with a density of 2702 kg / m³, a specific heat capacity of 2703 J / (kg·K), and a thermal conductivity of 237 W / (m·K). The dimensions of the cooling plate are 176 mm × 130 mm × 2 mm, with an inlet and outlet length of 15 mm and a flow channel depth of 0.6 mm. The cooling medium is water with an inlet water temperature of 303.15 K and a total flow rate of 4 g / s.

[0037] The phase change material has a specific heat capacity of 3000 J / (kg·K) and a density of 950 kg / m³. 3 The phase transition temperature is 315.15 ~ 317.15 K, the latent heat of phase transition is 141.7 kJ / kg, and the thermal conductivity is 7.654 W / (m·K).

[0038] The serpentine flow channel has a width of 9.5 mm, with 8 secondary flow channels, each 2 mm wide. The phase change material thickness distributions between the two rows of cells are [1.0, 1.0, 1.0, 4.0, 5.0, 7.0, 6.0, 5.0, 2.0] mm and [2.0, 5.0, 6.0, 7.0, 5.0, 4.0, 1.0, 1.0, 1.0] mm, respectively. The average temperature of each cell in the thermal management system of this invention and a single-channel serpentine cold plate coupled to a phase change material battery of the same volume was calculated using numerical simulation. Figure 3As shown, the battery pack with a dual-channel serpentine cooling plate system exhibits better temperature uniformity than that with a single-channel serpentine cooling plate system. The temperature difference of the battery pack with the dual-channel serpentine cooling plate system is 1.33 K, which is 1.49 K lower than that of the single-channel serpentine cooling plate system. The power consumption of the dual-channel serpentine cooling plate system, calculated through numerical simulation, is 0.0195 W, which is 66% lower than that of the single-channel serpentine cooling plate system. This example verifies that when this invention is used in battery thermal management, it can significantly reduce the temperature difference of the battery pack, improve the temperature uniformity of the battery pack, and reduce the energy consumption of the system.

[0039] Example 2 The system structure and operation settings of this embodiment are the same as those of Embodiment 1, except that the number of secondary flow channels is 10; the phase change material thickness distribution between the two rows of cells is [1.0, 1.0, 1.0, 3.0, 4.0, 12.0, 5.0, 4.0, 1.0] mm and [1.0, 4.0, 5.0, 12.0, 4.0, 3.0, 1.0, 1.0, 1.0] mm, respectively. The average temperature of each cell in the thermal management system of this invention and a single-channel serpentine cold plate coupled phase change material battery of the same volume was calculated through numerical simulation, as shown below. Figure 4 As shown, the battery pack with a dual-channel serpentine cooling plate system exhibits better temperature uniformity than that with a single-channel serpentine cooling plate system. The temperature difference of the battery pack with the dual-channel serpentine cooling plate system is 1.60 K, which is 1.83 K lower than that of the single-channel serpentine cooling plate system. The power consumption of the dual-channel serpentine cooling plate system, calculated through numerical simulation, is 0.0184 W, which is 67.9% lower than that of the single-channel serpentine cooling plate system. This example verifies that when this invention is used in battery thermal management, it can significantly reduce the temperature difference of the battery pack, improve the temperature uniformity of the battery pack, and reduce the energy consumption of the system.

[0040] Example 3 The system structure and operation settings of this embodiment are the same as those of Embodiment 1, except that the thickness of the cold plate is 9 mm, the channel depth is 2 mm, the number of secondary channels is 11, the inlet water temperature is 298.15 K, and the total flow rate is 2 g / s; the phase change material thickness distribution between the two rows of cells is [2.0, 1.0, 4.0, 4.0, 4.0, 7.0, 4.0, 4.0, 2.0] mm and [2.0, 4.0, 4.0, 7.0, 4.0, 4.0, 4.0, 1.0, 2.0] mm, respectively. The average temperature of each cell in the thermal management system of this invention and a single-channel serpentine cold plate coupled with a phase change material battery of the same volume was calculated through numerical simulation, as shown below. Figure 5As shown, the battery pack with a dual-channel serpentine cooling plate system exhibits better temperature uniformity than that with a single-channel serpentine cooling plate system. The temperature difference of the battery pack with the dual-channel serpentine cooling plate system is 0.9 K, which is 1.89 K lower than that of the single-channel serpentine cooling plate system. The power consumption of the dual-channel serpentine cooling plate system, calculated through numerical simulation, is 0.000158 W, which is 74.3% lower than that of the single-channel serpentine cooling plate system. This example verifies that when this invention is used in battery thermal management, it can significantly reduce the temperature difference of the battery pack, improve the temperature uniformity of the battery pack, and reduce the energy consumption of the system.

[0041] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A two-channel serpentine cold plate coupled phase change material thermal management system, characterized in that, It includes several batteries, a liquid cooling plate, and a phase change material (2); the top or bottom of each battery is tightly attached to the liquid cooling plate, the several batteries are arranged along the inner DC channel direction of the liquid cooling plate, and the phase change material (2) is filled between adjacent batteries.

2. A two-channel serpentine cold plate coupled phase change material thermal management system according to claim 1, wherein, The liquid cooling plate includes a metal substrate (9) and a metal cover plate (10), and the metal substrate (9) has multiple grooves as channels for fluid flow.

3. The dual-channel serpentine cold plate coupled phase change material thermal management system of claim 1, wherein, The liquid cooling plate includes multiple inlet sections (7), multiple outlet sections (8), several direct current channels (5), and several semi-circular curved channels (6) to form a multi-channel liquid cooling plate, with each channel being a serpentine channel.

4. The dual-channel serpentine cold plate coupled phase change material thermal management system of claim 3, wherein, The liquid cooling plate has a dual-channel design, with the fluids flowing in opposite directions within the dual channels, forming a counter-current flow.

5. The dual-channel serpentine cold plate coupled phase change material thermal management system of claim 3, wherein, Multiple secondary channels are set between the direct current channels in each serpentine flow channel (4).

6. The dual channel serpentine cold plate coupled phase change material thermal management system of claim 1, wherein, The battery is either a prismatic or cylindrical battery.

7. The dual-channel serpentine cold plate coupled phase change material thermal management system of claim 1, wherein, The batteries are arranged one or more rows along the DC channel direction in the liquid cooling plate.

8. The dual-channel serpentine cold plate coupled phase change material thermal management system of claim 7, wherein, Phase change material is filled between the two cells in each row.

9. A dual-channel serpentine cold plate coupled phase change material thermal management system according to claim 8, characterized in that, The phase change material (2) is non-uniformly distributed between every two cells, with less phase change material near the cell near the cold plate inlet than near the cell far from the cold plate inlet.

10. A dual-channel serpentine cold plate coupled phase change material thermal management system according to claim 1, characterized in that, Several batteries form a battery pack, and a liquid cooling plate is attached to the side of the battery pack.

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