Nested serpentine channel liquid cooling plate and battery thermal management system thereof

Abstract

This invention discloses a nested serpentine channel liquid cooling plate and its battery thermal management system, belonging to the field of energy storage battery thermal management technology. The liquid cooling plate has a double-inlet, double-outlet serpentine flow channel inside, forming two parallel coolant flow paths to shorten the heat transfer path and improve temperature uniformity. A battery thermal management system includes a battery module composed of multiple square batteries and at least one liquid cooling plate, which is nested between the battery cells. Preferably, for a module composed of 20 square batteries, only three liquid cooling plates are used, respectively arranged on both sides and in the middle of the module, achieving a compact configuration of "one cooling plate cooling two battery cells". More preferably, the liquid cooling plate adopts an inlet / outlet direction of left-up-right-down and right-up-left-down, with a coolant mass flow rate of 1 g / s and an inlet temperature of 25°C. Experimental results show that at an ambient temperature of 45℃ and a discharge rate of 2C, the battery module's highest temperature is 28.75℃, the maximum temperature difference is 2.17℃, the voltage drop is 229.31Pa, and the comprehensive performance evaluation index PEC reaches 4.02. This invention significantly reduces system complexity, manufacturing costs, and flow resistance while ensuring efficient heat dissipation and excellent temperature uniformity, making it suitable for large-scale lithium iron phosphate energy storage modules.

Description

Technical Field

[0001] This invention belongs to the field of energy storage battery thermal management technology, specifically relating to a nested dual-inlet dual-outlet serpentine channel liquid cooling plate for lithium iron phosphate (LFP) battery modules, and a battery thermal management system including the liquid cooling plate. Background Technology

[0002] With the continuous and rapid growth of installed capacity of renewable energy sources such as wind and solar power, the demand for large-capacity, long-duration, and highly reliable energy storage systems in the power grid has surged. Energy storage power stations, as core equipment for mitigating renewable energy fluctuations, achieving peak shaving and valley filling in the power grid, and ensuring the safe and stable operation of the power system, have entered the stage of large-scale application. Lithium iron phosphate (LFP) batteries, with their advantages of good thermal stability, long cycle life, low cost, and cobalt-free environmental friendliness, have become the preferred cell type for current grid-scale energy storage power stations and are widely used in centralized energy storage systems at the megawatt-hour level and above.

[0003] The electrochemical performance and safety of lithium iron phosphate batteries are extremely sensitive to operating temperature, with an optimal operating temperature range of 20℃ to 45℃. The maximum temperature difference between individual cells within the module must be strictly controlled within 5℃. Excessive temperature accelerates electrolyte decomposition, triggers side reactions, shortens cycle life, and may even induce thermal runaway; excessively low temperature leads to capacity decay during charge and discharge, increased polarization, and easy formation of lithium dendrites, posing a risk of internal short circuits. Under the coupled conditions of high-rate charge and discharge and high-temperature environments, battery heat generation is concentrated, heat dissipation is difficult, and uneven temperature distribution becomes more prominent, directly restricting the safety, reliability, and lifespan of the energy storage system. Therefore, a high-performance thermal management system has become an indispensable key component of large-capacity energy storage battery modules.

[0004] Currently, battery thermal management technologies are mainly divided into four categories: air cooling, liquid cooling, phase change material cooling, and hybrid cooling. Air cooling systems are simple in structure, low in cost, and easy to maintain, but the low thermal conductivity and specific heat capacity of air limit their heat dissipation capacity, making it difficult to meet the heat dissipation requirements of high power density energy storage modules. Phase change material cooling relies on latent heat for passive heat dissipation, requiring no external power, but its low thermal conductivity and susceptibility to heat saturation and leakage problems limit its engineering applicability. Liquid cooling technology achieves forced convection heat transfer through the circulation of coolant within the flow channel, achieving a heat dissipation efficiency 3 to 5 times that of air cooling. It has advantages such as strong heat dissipation capacity, high temperature control accuracy, and good adaptability to operating conditions, and has become the mainstream technical solution for thermal management of medium- and high power density energy storage batteries.

[0005] However, existing traditional liquid cooling systems still face numerous technical bottlenecks in practical engineering applications: First, conventional single serpentine flow channels are long and have many bends, causing the coolant to continuously absorb heat and rise in temperature along the flow path. This results in a significant decrease in heat exchange capacity at the rear of the flow channel, leading to a noticeable "cold at the front and hot at the back" phenomenon in the battery module, poor temperature uniformity, and a maximum temperature difference far exceeding the 5°C safety threshold. Second, the long flow channel and dense bends result in high flow resistance, high system pressure drop, and increased power consumption of the circulating pump, thus increasing the system's energy consumption. Third, existing liquid cooling solutions mostly adopt a "one battery, one plate" configuration, meaning a single battery corresponds to a single liquid cooling plate. While this can improve local heat exchange, it significantly increases the amount of liquid cooling plates used, pipeline complexity, number of sealing points, and manufacturing costs, while also increasing the risk of leakage and assembly difficulty. Fourth, most flow channel optimization studies only focus on the performance of a single cooling plate, lacking systematic research on the overall thermal behavior, flow distribution uniformity, and low-cost integration solutions of battery modules with multiple cooling plates nested together. This makes it difficult to simultaneously meet the collaborative design requirements of efficient heat dissipation, low temperature difference, low flow resistance, and low cost.

[0006] Therefore, current liquid cooling technology for energy storage batteries cannot simultaneously address heat dissipation performance, temperature uniformity, flow resistance, and system economy. There is an urgent need to develop a new type of liquid cooling plate and thermal management system that is compact, has high heat exchange efficiency, good temperature uniformity, low flow resistance, and low cost to meet the safe and stable operation requirements of large-scale energy storage power stations under high-rate and high-temperature conditions. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a nested double-inlet double-outlet serpentine channel liquid cooling plate and its battery thermal management system that is compact in structure, has high heat dissipation efficiency, good temperature uniformity, low flow resistance and low cost.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A nested dual-inlet dual-outlet serpentine channel liquid cooling plate (ESLCP) is used for thermal management of battery modules. Its key feature is that the liquid cooling plate has a dual-inlet dual-outlet serpentine flow channel inside, the channel including two inlets and two outlets, forming two parallel coolant flow paths.

[0009] Furthermore, the dual-inlet and dual-outlet serpentine flow channel is a parallel multi-channel layout, which is used to significantly shorten the heat transfer path of a single coolant and to ensure that the coolant maintains efficient heat exchange throughout the liquid cooling plate.

[0010] A battery thermal management system, characterized in that it comprises: A battery module consisting of multiple square batteries (e.g., IFP20100140A-27Ah LFP batteries); and at least one liquid cooling plate as described above; The liquid cooling plate is nested between the cells of the battery module.

[0011] Furthermore, for a module consisting of 20 square batteries, a total of 3 nested dual-inlet dual-outlet serpentine channel liquid cooling plates are set up, with two plates arranged on both sides of the battery module and one plate arranged in the middle of the battery module. Each liquid cooling plate is attached to the side of its two adjacent cells to achieve the configuration of "one cooling plate cooling two cells", thereby reducing the total amount of liquid cooling plates used in the system.

[0012] Furthermore, the two inlets and two outlets of the liquid cooling plate are arranged in the following directions: upper left corner inlet, lower left corner outlet, lower right corner inlet, and upper right corner outlet (i.e., Case 4: upper left and lower right inlet, upper right and lower left outlet). This flow direction forms a cross convection with the natural convection direction (upward) formed by the heat generated by the battery, so as to further enhance local heat exchange and temperature uniformity.

[0013] Furthermore, the mass flow rate of the coolant (such as water) in the liquid cooling plate is 0.5-5 g / s, most preferably 1 g / s.

[0014] Furthermore, the coolant inlet temperature of the liquid cooling plate is 20-35℃, with 25℃ being the most preferred.

[0015] Compared with the prior art, the present invention has the following beneficial effects: Superior heat dissipation and temperature uniformity: The nested dual-inlet, dual-outlet serpentine channel liquid cooling plate proposed in this invention avoids the temperature rise problem at the end of the coolant caused by traditional long-flow serpentine channels through its parallel flow channel design. Experiments have shown that, compared with traditional single-serpentine channels and confluence-type serpentine channels, this invention can reduce the maximum temperature of the battery module (T0) to [amount missing]. b,max The temperature drops by approximately 15.2°C and 3.9°C respectively, and the maximum temperature difference (ΔTb) decreases by approximately 16.35°C and 1.31°C respectively.

[0016] Reduce system complexity and cost: By nesting liquid cooling plates between two rows of cells (three cooling plates cooling twenty cells), the existing "one cell, one plate" configuration mode is changed, which significantly reduces the number of cooling plates used, simplifies the system structure, and reduces manufacturing costs and leakage risk.

[0017] Flow resistance and energy consumption optimization: The optimized dual-inlet, dual-outlet flow channel layout effectively shortens the flow path and reduces bends. While ensuring excellent cooling performance, the system pressure drop (Δp) is controlled at 229.31 Pa (at a flow rate of 1 g / s), achieving a good balance between thermal performance and pump power consumption. The comprehensive performance evaluation index (PEC) shows that a PEC of 4.02 can be achieved at a flow rate of 1 g / s, making it the optimal choice.

[0018] High adaptability: This invention is applicable to large-scale lithium iron phosphate energy storage modules, and can still control the battery module temperature within the optimal operating range under medium and high discharge rates (such as 2C) and high ambient temperatures (such as 45°C). Attached Figure Description

[0019] Figure 1 The diagram shows (a) the LFP battery, (b) the battery pack and liquid cooling plate arrangement, (c) the LCP geometry and (d) the LCP internal flow channel structure in the embodiments of the present invention.

[0020] Figure 2 This is a comparison of temperature and pressure cloud maps for different serpentine flow channels (single serpentine, confluence type, and dual inlet and dual outlet of the present invention) in the embodiments of the present invention.

[0021] Figure 3 The temperature and pressure cloud diagrams are shown for four different inlet and outlet directions (Case 1-Case 4) of the liquid cooling plate of the present invention in the embodiments of the present invention.

[0022] Figure 4 The temperature cloud diagrams of the liquid cooling plate of the present invention under different mass flow rates (0.5-5 g / s) are shown in the embodiments of the present invention.

[0023] Figure 5 The pressure cloud diagrams of the liquid cooling plate of the present invention under different mass flow rates (0.5-5 g / s) are shown in the embodiments of the present invention.

[0024] Figure 6 This is a bar chart showing the comprehensive performance evaluation index (PEC) of the liquid cooling plate of the present invention under different mass flow rates in an embodiment of the present invention.

[0025] Figure 7 The above are temperature and pressure cloud diagrams of the liquid cooling plate of the present invention under different inlet temperatures (20-35℃) in the embodiments of the present invention.

[0026] Figure 8 This is a bar chart showing the comprehensive performance evaluation index (PEC) of the liquid cooling plate of the present invention under different inlet temperatures in an embodiment of the present invention. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1: This embodiment provides a thermal management system for a 20-cell IFP20100140A-27Ah square LFP battery module connected in series. The battery dimensions are 140mm × 100mm × 20mm, as shown below. Figure 1 As shown in (a).

[0029] The system comprises three nested, dual-inlet, dual-outlet serpentine channel liquid cooling plates (made of aluminum). For example... Figure 1 As shown in (b), two cold plates are arranged on both sides of the battery module and one is arranged in the center of the module. Each cold plate is in close contact with the large surface of the adjacent cells on both sides to achieve efficient heat conduction.

[0030] The internal flow channels of the liquid cooling plate are double-inlet, double-outlet serpentine channels, such as... Figure 1 As shown in (d). Water was used as the coolant, with an inlet temperature set at 25℃ and a mass flow rate of 1 g / s. Boundary conditions were set as follows: ambient temperature 45℃, battery pack discharged at a 2C rate (100% depth of discharge), and the natural convection heat transfer coefficient between the outer surface of the battery pack and the air was 5 W·m⁻²·K⁻¹. A pressure-based solver was used in conjunction with the SIMPLE algorithm to solve the three-dimensional unsteady Navier-Stokes equations.

[0031] Simulation and experimental results show (see) Figure 2 , Figure 5 Under these optimal parameters, the highest temperature T of the battery module at the end of discharge is... b,max The maximum temperature difference is only 28.75℃, with a maximum temperature difference ΔT. b At a temperature as low as 2.17℃, the system voltage drop Δp is 229.31Pa, and the comprehensive performance evaluation index PEC reaches 4.02. Under the aforementioned harsh operating conditions, this module still operates within its optimal temperature range (20-45℃) and exhibits excellent temperature consistency.

[0032] Comparative Example 1: Compared to Example 1, the difference lies in the use of a traditional single serpentine flow channel cold plate (SSLCP). Under the same operating conditions (2C discharge, 45°C environment), the battery module T... b,max Up to 43.95℃, ΔT b The temperature reached 18.52℃, and the Δp was 1000.46 Pa. This indicates that the solution of the present invention has significant advantages in heat dissipation and temperature uniformity.

[0033] Comparative Example 2: Compared to Example 1, the difference lies in the use of a serpentine flow channel cold plate (CSLCP). Under the same operating conditions, the battery module T... b,max The temperature is 32.65℃, and ΔT b The temperature was 3.48℃, and the pressure drop (Δp) was 110.33 Pa. This indicates that the present invention significantly improves temperature uniformity and cooling effect at the cost of sacrificing a very small portion of the pressure drop.

[0034] Example 2: The results are basically the same as in Example 1, except that the inlet direction of the liquid cooling plate is changed, adopting an inlet from the upper left to the lower right and an outlet from the upper right to the lower left (Case 4). Figure 3 As shown, this scheme exhibits the best battery module temperature uniformity, ΔTb With a temperature of only 2.17℃, it performed best compared to other directions (ΔTb for Cases 1-3 were 2.19℃, 2.24℃, and 2.22℃, respectively).

[0035] Example 3: It is basically the same as Example 1, except that the coolant mass flow rate is changed. For example... Figure 4 , 5 As shown, when the flow rate is 0.5 g / s, Δp is only 110.28 Pa, but T b,max The temperature was 32.84℃, and the ΔT was... b The temperature was 3.73℃; when the flow rate was 5 g / s, T b,max As low as 26.31℃, ΔT b At only 0.99℃, Δp surges to 1463.66 Pa. Based on comprehensive PEC evaluation, 1 g / s is the optimal choice.

[0036] Example 4: It is basically the same as Example 1, except that the coolant inlet temperature is changed. Figure 6 , 7 As shown, as the inlet temperature rises from 20℃ to 35℃, T b,max Rise, ΔT b The temperature decreases. Based on the comprehensive PEC evaluation, 25℃ is the optimal inlet temperature, which can avoid the risk of condensation while ensuring the cooling driving force.

[0037] In summary, this invention effectively solves the problems of large temperature difference, high flow resistance, and high cost in existing energy storage battery liquid cooling technology through its innovative nested double-inlet double-outlet serpentine channel liquid cooling plate and system integration scheme, and has outstanding substantive features and significant progress.

Claims

1. A nested serpentine channel liquid cooling plate for thermal management of battery modules, characterized in that: The liquid cooling plate is equipped with a double-inlet, double-outlet serpentine flow channel, which includes two inlets and two outlets, forming two parallel coolant flow paths.

2. The nested double-inlet double-outlet serpentine channel liquid cooling plate according to claim 1, characterized in that: The dual-inlet and dual-outlet serpentine flow channel is a parallel multi-channel layout used to shorten the heat transfer path of a single coolant.

3. A battery thermal management system, characterized in that, include: A battery module consisting of multiple square batteries; and at least one liquid cooling plate as described in claim 1 or 2; wherein the liquid cooling plate is nested between the cells of the battery module.

4. The battery thermal management system according to claim 3, characterized in that: The battery module consists of 20 square batteries, and the system is equipped with a total of 3 liquid cooling plates; two liquid cooling plates are respectively arranged on both sides of the battery module, and one liquid cooling plate is arranged in the middle of the battery module. Each liquid cooling plate is attached to the side of the two adjacent battery cells.

5. The battery thermal management system according to claim 3, characterized in that: The liquid cooling plate is arranged with two inlets and two outlets as follows: upper left and lower right inlet, and lower left and upper right outlet, so that the flow direction intersects with the natural convection direction formed by the heat generated by the battery.

6. The battery thermal management system according to claim 3, characterized in that: The mass flow rate of the coolant in the liquid cooling plate is from 0.5 g / s to 5 g / s, preferably 1 g / s.

7. The battery thermal management system according to claim 3, characterized in that: The coolant inlet temperature of the liquid cooling plate is 20°C to 35°C, preferably 25°C.

8. The battery thermal management system according to claim 3, characterized in that: The square battery is a lithium iron phosphate (LFP) battery.

9. An energy storage power station, characterized in that: A battery thermal management system comprising any one of claims 3 to 8.

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