A method for optimizing cooling performance of a power battery liquid cooling plate

Abstract

The application relates to the field of power battery thermal management, in particular to a method for optimizing the cooling performance of a liquid cooling plate of a power battery. The optimization method first calculates an estimated value of the heat dissipation requirement of a power battery pack, and determines the size range of a liquid cooling pipe inside the liquid cooling plate and the peripheral size of the liquid cooling plate; the topology form of the liquid cooling circuit is determined, the size parameters and the topology position parameters of each section of the liquid cooling plate pipe are taken as variables, and an optimization model is constructed; the heat transfer efficiency of the liquid cooling pipe is improved by using a reinforced heat transfer unit to realize turbulence reinforcement and heat transfer reinforcement; then, a multi-layer optimization method is used to step by step optimize the liquid cooling pipe, the arrangement mode of the reinforced heat transfer unit and the size of the reinforced heat transfer unit, so that the NP problem is avoided to be solved, the solving efficiency is high, and an optimization scheme meeting the engineering requirement can be obtained. The application can perform multi-objective optimization on different performance indexes of the liquid cooling pipe, and therefore has wide applicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power battery thermal management, and particularly relates to a method for optimizing the cooling performance of a liquid cooling plate of a power battery. BACKGROUND

[0002] With the rapid development of electric vehicles and energy storage systems, the energy density of power batteries is increasing year by year, and the fast charging technology is rapidly developing, so the heat dissipation demand of power batteries is becoming higher and higher, and the performance of the thermal management system has increasingly become a bottleneck technology restricting the development of the new energy vehicle industry. An efficient heat dissipation system not only helps to improve the performance of power batteries, but also prolongs the service life of power batteries and ensures safety.

[0003] A liquid cooling system is usually used for thermal management of a vehicle power battery. Liquid cooling pipes are arranged in the liquid cooling plate, and most of the liquid cooling pipes adopt an S-shaped topology. On the one hand, the structure is simple and can be formed by one-time stamping, and on the other hand, the heat dissipation demand of the entire battery pack can be basically guaranteed. A plurality of parallel liquid cooling pipes can be arranged or the pipe topology can be optimized to avoid a too large temperature difference between the inlet and outlet of the pipe, thereby improving the temperature consistency of the battery pack.

[0004] Most of the liquid cooling plates used in existing electric vehicles adopt smooth cooling pipes, while arranging concave-convex units, fins and other heat transfer enhancement units in the liquid cooling pipes can significantly improve the heat transfer efficiency and meet the heat dissipation demand of the new generation of power batteries with large capacity and high energy density. However, due to the introduction of the heat transfer enhancement units, the design variables increase significantly. In fact, the optimization problem of such a liquid cooling plate belongs to an NP problem, and there are problems such as high solution complexity and low efficiency. SUMMARY

[0005] The present application aims at the deficiencies of the prior art and provides a method for optimizing the cooling performance of a liquid cooling plate with heat transfer enhancement units for a vehicle power battery. The heat transfer enhancement units are used to realize turbulence enhancement and heat transfer enhancement, thereby improving the heat transfer efficiency of the liquid cooling pipes. Then, a multi-layer optimization method is used to step by step optimize the liquid cooling pipes, the arrangement mode of the heat transfer enhancement units and the size of the heat transfer enhancement units, which not only avoids solving the NP problem, but also meets the actual engineering requirements.

[0006] The technical scheme provided by the present application is as follows:

[0007] A method for optimizing the cooling performance of a liquid cooling plate of a power battery, comprising the following steps:

[0008] Step 1: calculating the estimated value of the heat dissipation demand of the power battery pack and determining the size range of the liquid cooling pipes inside the liquid cooling plate and the peripheral size of the liquid cooling plate;

[0009] Step two: determine the liquid cooling loop topology, take the size parameters and topology position parameters of the liquid cooling plate pipeline as variables, build a first optimization model, and use the first optimization model to obtain the smoothest pipeline scheme with the best performance;

[0010] Step three: taking the optimal smooth pipeline scheme obtained in step two as the initial scheme, arranging the enhanced heat transfer unit combination on the pipeline wall surface, taking the enhanced heat transfer unit type and unit combination mode as variables, building a second optimization model, and using the second optimization model to obtain the optimal enhanced heat transfer unit combination scheme;

[0011] Step four: taking the optimal smooth pipeline scheme obtained in step two as the initial scheme, using the optimal enhanced heat transfer unit combination scheme obtained in step three, taking the geometric size of the enhanced heat transfer unit and the arrangement size of the unit combination as variables, building a third optimization model, and using the third optimization model to obtain the pipeline scheme with the best cooling performance of the liquid cooling plate of the power battery.

[0012] The above method further comprises the following steps: calculating the heat dissipation requirement estimation of the power battery pack in step one, constructing a power battery model by using an RC equivalent circuit model, obtaining battery data by using HPPC experiment, and obtaining model parameters of the RC equivalent circuit model by using parameter identification.

[0013] In the optimization method, the term "enhanced heat transfer unit" is used to represent functional elements such as pits, bulges, fins, vortex generators, etc. with various shapes that can achieve turbulence enhancement. The terms "enhanced heat transfer unit combination" and "unit combination arrangement" are used to represent the combination of enhanced heat transfer units that can achieve turbulence enhancement, and have the same meaning, referring to the combination and arrangement of enhanced heat transfer units of the same type with the same shape and size, the combination of enhanced heat transfer units of the same type with different shapes and sizes, and the combination of enhanced heat transfer units of different types.

[0014] The above method further comprises the following steps: calculating the heat dissipation requirement estimation of the power battery pack in step one, constructing a power battery model by using an RC equivalent circuit model, obtaining battery data by using HPPC experiment, and obtaining model parameters of the RC equivalent circuit model by using parameter identification.

[0015]

[0016] wherein n is the order of the RC equivalent circuit model, R i (i = 0, 1, 2…, n) is the resistance of each stage of the RC equivalent circuit model, I is the maximum working current of the RC equivalent circuit model, and S is the safety factor.

[0017] The above method further comprises the following steps: calculating the heat dissipation requirement estimation of the power battery pack in step one, constructing a power battery model by using an RC equivalent circuit model, obtaining battery data by using HPPC experiment, and obtaining model parameters of the RC equivalent circuit model by using parameter identification.

[0018] The method further utilizes flow-heat coupling simulation analysis to analyze the cooling performance of each scheme and the optimized scheme in steps two to four.

[0019] The method further directly adopts the enhanced heat transfer unit combination scheme of alternate straight line arrangement of concave-convex in step three without further optimization design.

[0020] In step four, when the enhanced heat transfer unit is a concave pit, the concave pit width and the ratio of the depth to the width are selected as the optimization variables; the concave pit width W d is in the range of 0.5W≤W d ≤0.83W, wherein W is the flow passage width, the ratio δ d of the depth to the width of the concave pit is in the range of 0.1≤δ d ≤0.3.

[0021] In step four, when the enhanced heat transfer unit is a convex bump, a fin or a vortex generator, the flow-approaching width, i.e., the dimension of the enhanced heat transfer unit perpendicular to the flow direction, and the ratio of the depth to the width are selected as the optimization variables.

[0022] When the enhanced heat transfer unit arranged in the upstream region is a concave pit, the enhanced heat transfer unit width is in the range of:

[0023] 1.2W d ≤W p ≤W, wherein W d is the width of the concave pit, W is the flow passage width, and W p is the width of the convex bump.

[0024] In other working conditions, the enhanced heat transfer unit width is in the range of 0.5W≤W p ≤W.

[0025] When the enhanced heat transfer unit is a convex bump, the ratio δ p of the height to the width is in the range of 0.1 to 0.3.

[0026] Compared with the prior art, the present application has the following characteristics:

[0027] (1) The present application utilizes the enhanced heat transfer unit to realize turbulent flow enhancement and heat transfer enhancement, greatly improves the heat transfer efficiency of the liquid cooling pipeline, and can better meet the increasing energy density and heat dissipation requirements of power batteries.

[0028] (2) The application solves the optimization problem of the enhanced heat transfer pipeline by using two to three layers of orthogonal tests, avoids the original combination optimization nested parameter optimization solving mode, and adopts three layers of orthogonal optimization to step by step optimize the liquid cooling pipeline, the arrangement mode of the enhanced heat transfer unit and the size of the enhanced heat transfer unit, so as to not only avoid solving the NP problem, but also have high solving efficiency, and be capable of obtaining an optimization scheme meeting the engineering requirements.

[0029] (3) The application can perform multi-objective optimization on different performance indexes of the liquid cooling pipeline, and therefore has wide applicability. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a flowchart of the optimization method of the application.

[0031] Figure 2 It is a schematic diagram of a power battery liquid cooling system used when the optimization method of the application is executed.

[0032] Figure 3 It is a liquid cooling pipeline inside a liquid cooling plate used when the optimization method of the application is executed.

[0033] Figure 4 It is a schematic diagram of the arrangement of fins as the enhanced heat transfer unit inside the liquid cooling pipeline in Example 1.

[0034] Figure 5 It is a schematic diagram of the geometric size and arrangement size parameters of a single fin in Example 1.

[0035] Figure 6 It is a schematic diagram of the geometric size and arrangement size parameters of a single dimple in Example 2.

[0036] Figure 7 It is a schematic diagram of the geometric size and arrangement size parameters of a single convex hull in Example 3.

[0037] Figure 8 It is a schematic diagram of the arrangement of the fin-dimple alternate straight line arrangement as the enhanced heat transfer unit combination scheme inside the liquid cooling pipeline in Example 4.

[0038] Figure 9 It is a schematic diagram of the arrangement of the fin-convex hull alternate straight line arrangement as the enhanced heat transfer unit combination scheme inside the liquid cooling pipeline in Example 5.

[0039] Figure 10 It is a schematic diagram of the arrangement of the dimple-convex hull alternate straight line arrangement as the enhanced heat transfer unit combination scheme inside the liquid cooling pipeline in Example 6.

[0040] Figure 11The schematic diagram of the liquid cooling pipe internal arrangement of the embodiment 7 is shown in the figure.

[0041] Explanation of reference numerals in the figure: 1. power battery pack, 2. liquid cooling plate, 3. fin, 4. dimple, 5. bump. DETAILED DESCRIPTION

[0042] The content of the application is further described in detail below in combination with the figures and embodiments, but is not used as the basis for any limitation on the application. The advantages of the application can be further illustrated by the following simulation examples:

[0043] Embodiment 1

[0044] In the design stage, the heat dissipation requirement of the power battery pack is estimated by the second-order RC model. In the optimization stage, the orthogonal test model is used to optimize the liquid cooling pipe to obtain the optimal performance scheme and arrange the fins as the heat transfer enhancement unit in the liquid cooling pipe, so as to improve the heat dissipation performance of the liquid cooling system. This embodiment has the advantages of simple structure, high efficiency, good heat dissipation effect, etc.

[0045] The optimization method refers to Figure 1 , and the specific steps are as follows:

[0046] Step one: calculate the heat dissipation requirement estimation of the power battery pack, and determine the size range of the liquid cooling pipe inside the liquid cooling plate and the peripheral size of the liquid cooling plate;

[0047] A second-order RC model is constructed, and the model parameters are obtained by using HPPC experimental data and parameter identification. For the second-order RC equivalent circuit model, the calculation method of the heat dissipation requirement estimation of the power battery pack is:

[0048] Q = S (R0 + R1 + R2) I 2

[0049] Wherein, R0 is the ohmic resistance of the second-order RC equivalent circuit model, R i is the resistance parameter of the high-order RC equivalent circuit model;

[0050] According to the size of the battery pack in Figure 2 , a magnification of 1.2 times is used to determine the peripheral size of the liquid cooling plate and the size range of the liquid cooling pipe inside the liquid cooling plate;

[0051] Step two: determine the topology form of the liquid cooling circuit, take the size parameters and topology position parameters of each section of the liquid cooling plate pipe as variables, construct a first optimization model, and obtain the optimal performance smooth pipe scheme by using the first optimization model;

[0052] The topology of the liquid cooling plate pipe is shown in Figure 3As shown, select the inlet height H, inlet width W of the liquid cooling plate, and the width D of each internal liquid cooling pipe i The parameters of are variables, and the objective function is to maximize the average Nusselt number of the liquid cooling pipe wall. An orthogonal test table for the liquid cooling plate pipe is constructed, as shown in Table 1. After solving, the optimal smooth pipe optimization scheme is obtained.

[0053] Table 1 Orthogonal test table of liquid cooling plate pipeline

[0054]

[0055]

[0056] Step 3: Using the optimal smooth pipe optimization solution obtained in step 2 as the initial solution, fins are arranged inside the pipe as heat transfer enhancement units, such as Figure 4 As shown;

[0057] Step 4: If Figure 5 As shown in Figure 2, the fin length L, height ratio λ, layout angle α and other dimensional parameters as well as layout spacing D and other topological parameters are selected as optimization variables. The objective function is to maximize the average Nusselt number of the liquid cooling pipe wall. An orthogonal test model is constructed. The orthogonal test table is shown in Table 2. After solving, the optimal performance pipeline solution is obtained.

[0058] Table 2 Orthogonal test table of fins as enhanced heat transfer units

[0059]

[0060]

[0061] Example 2

[0062] During the design phase, heat flux is used to estimate the power battery pack's heat dissipation requirements. During the optimization phase, the liquid cooling circuit is optimized to achieve the optimal performance solution. Pits are then placed in the cooling circuit to enhance heat transfer, thereby improving the cooling performance of the liquid cooling system. This embodiment offers advantages such as simplicity and high efficiency.

[0063] Optimization method reference Figure 1 , the specific steps are as follows:

[0064] Step 1: The heat flux applied to the surface of the liquid cooling plate is used as an estimate of the power battery pack's heat dissipation requirements. The calculation method is:

[0065] Q=qAΔt

[0066] Where Q is the estimated heat dissipation demand of the power battery pack, q is the heat flux per unit area, A is the surface area of ​​the liquid cooling plate, and Δt is the time interval for heat transfer;

[0067] Step two is same as example 1;

[0068] Step three: taking the optimal smooth pipe optimization scheme obtained in step two as the initial scheme, selecting the dimple as the heat transfer enhancement unit, as shown in Figure 6 ;

[0069] Step four: as shown in Figure 6 , selecting the width W d of the dimple, the depth H d of the dimple and the ratio δ d of the width W d as the size parameters, and selecting the arrangement spacing D as the topological parameter as the variables, constructing an orthogonal test model with the maximum average Nusselt number of the liquid cooling pipe wall surface as the objective function, the orthogonal test table is shown in Table 3, and the optimal pipe scheme is obtained after solving;

[0070] Table 3 orthogonal test table of dimple as heat transfer enhancement unit

[0071]

[0072] Step five: the HPPC experimental data is imported into the second-order RC equivalent circuit model and the heat dissipation requirement of the power battery pack is estimated, which is applied to the initial scheme of the liquid cooling plate, the optimal smooth pipe optimization scheme in step two, the optimal heat transfer enhancement combination scheme in step three and the performance optimal pipe scheme in step four respectively, and the maximum average Nusselt number of the liquid cooling pipe wall surface is compared to verify the effectiveness of the optimization method.

[0073] Example 3

[0074] In the design stage, the heat source is used as the estimation of the heat dissipation requirement of the power battery pack. In the optimization stage, the liquid cooling pipe is optimized to obtain the performance optimal scheme and the fin is arranged as the heat transfer enhancement unit, so as to improve the heat dissipation performance of the liquid cooling system. This example has the advantages of simple structure, high efficiency, good heat dissipation effect and the like.

[0075] The optimization method refers to Figure 1 , and the specific steps are as follows:

[0076] Step one: the heat flux applied to the surface of the liquid cooling plate is used as the estimation of the heat dissipation requirement of the power battery pack, and the calculation method is as follows:

[0077]

[0078] Wherein, I is the current intensity when the battery is charging and discharging, R is the battery internal resistance, T is the battery temperature, temperature influence coefficient;

[0079] Step two is same as example 1;

[0080] Step three: take the optimal smooth pipe optimization scheme obtained in step two as the initial scheme, and arrange convex hulls inside the pipe as the enhanced heat transfer unit, as shown in Figure 7 ;

[0081] Step four: as shown in Figure 7 , select the width W p of the convex hull, the height H P of the convex hull, and the ratio δ p of the width W p as the size parameters, and select the arrangement spacing D as the topological parameter as the variable, maximize the average Nusselt number of the liquid cooling pipe wall surface as the objective function, construct an orthogonal test model, and the orthogonal test table is shown in Table 4 below. After solving, the optimal pipe scheme is obtained;

[0082] Table 4 Orthogonal test table of convex hull as enhanced heat transfer unit

[0083]

[0084] The verification part is the same as that of Example 2.

[0085] Example 4

[0086] In the optimization stage, the liquid cooling pipe is optimized to obtain the optimal performance scheme, and the fin-pit alternating straight line arrangement of the enhanced heat transfer unit combination scheme is used in the liquid cooling pipe, so as to improve the heat dissipation performance of the liquid cooling system. This example has the advantages of simple structure, high efficiency, good heat dissipation effect, etc.

[0087] The optimization method refers to Figure 1 , steps three and four are implemented according to the following process, and the other steps are the same as those of Example 1:

[0088] Step three: take the optimal smooth pipe optimization scheme obtained in step two as the initial scheme, and arrange the fin-pit alternating straight line arrangement of the enhanced heat transfer unit combination scheme inside the pipe, as shown in Figure 8 ;

[0089] Step four: select the length L of the fin, the height ratio λ of the fin, the arrangement angle α of the fin, the width W d of the pit, and the ratio δ d of the depth and width of the pit as the size parameters, and select the arrangement spacing D as the topological parameter as the variable, maximize the average Nusselt number of the liquid cooling pipe wall surface as the objective function, construct an orthogonal test model, and the orthogonal test table is shown in Table 5 below. After solving, the optimal pipe scheme is obtained;

[0090] Table 5 Orthogonal test table of fin-pit alternating straight line arrangement

[0091]

[0092]

[0093] The verification part is the same as that of Example 2.

[0094] Example 5

[0095] In the optimization stage, the liquid cooling pipeline is optimized to obtain the optimal performance scheme, and the fin-bulge alternating straight line arrangement of the enhanced heat transfer unit combination scheme is adopted in the liquid cooling pipeline, so as to improve the heat dissipation performance of the liquid cooling system. This embodiment has the advantages of simple structure, high efficiency, good heat dissipation effect, etc.

[0096] The optimization method refers to Figure 1 , steps three and four are implemented according to the following flow, and other steps are the same as those of Example 1:

[0097] Step three: taking the optimal smooth pipeline optimization scheme obtained in step two as the initial scheme, arranging the fin-bulge alternating straight line arrangement of the enhanced heat transfer unit combination scheme in the pipeline, as shown in Figure 9 ;

[0098] Step four: selecting the length L of the fin, the height ratio λ of the fin, the arrangement angle α of the fin, the width W p of the bulge, the height and width ratio δ p of the bulge as dimension parameters, and selecting the arrangement spacing D as a topological parameter as variables, taking the maximum average Nusselt number of the wall surface of the liquid cooling pipeline as the objective function, constructing an orthogonal test model, and the orthogonal test table is shown in Table 6. The optimal performance pipeline scheme is obtained after solving;

[0099] Table 6 Orthogonal test table of fin-bulge alternating straight line arrangement

[0100]

[0101]

[0102] The verification part is the same as that of Example 2.

[0103] Example 6

[0104] In the optimization stage, the liquid cooling pipeline is optimized to obtain the optimal performance scheme, and the fin-bulge alternating straight line arrangement of the enhanced heat transfer unit combination scheme is adopted in the liquid cooling pipeline, so as to improve the heat dissipation performance of the liquid cooling system. This embodiment has the advantages of simple structure, high efficiency, good heat dissipation effect, etc.

[0105] The optimization method refers to Figure 1 , steps three and four are implemented according to the following flow, and other steps are the same as those of Example 1:

[0106] Step 3: Using the optimal smooth pipeline optimization solution obtained in step 2 as the initial solution, a heat transfer enhancement unit combination solution with alternating concave and convex hulls arranged in a straight line is arranged inside the pipeline, such as Figure 10 As shown;

[0107] Step 4: Select the width W of the pit d , the ratio of the depth and width of the pit δ d , the width of the convex hull W p , the ratio of the height and width of the convex hull δ p As the size parameter, the layout spacing D is selected as the topological parameter variable, and the objective function is to maximize the average Nusselt number of the liquid cooling pipe wall. The orthogonal test model is constructed. The orthogonal test table is shown in Table 7. After solving, the pipeline scheme with the best performance is obtained;

[0108] Table 7 Orthogonal test table of alternating straight line arrangement of pits and convex hulls

[0109]

[0110] The verification part is the same as Example 2.

[0111] Example 7

[0112] During the optimization phase, the liquid cooling circuit was optimized to achieve the optimal performance. A heat transfer enhancement scheme was implemented within the cooling circuit, employing a linear arrangement of alternating fins, dimples, and convex ridges. This enhanced heat dissipation performance was enhanced. This embodiment offers advantages such as a simple structure, high efficiency, and excellent heat dissipation.

[0113] Optimization method reference Figure 1 , the other steps are the same as those in method embodiment 1, and step 3 is implemented according to the following process:

[0114] Step 3: Using the optimal smooth pipeline optimization solution obtained in step 2 as the initial solution, a heat transfer enhancement unit combination solution with alternating straight lines of fins, dimples, and convex hulls is arranged inside the pipeline, such as Figure 11 As shown;

[0115] Step 4: Select the fin length L, fin height ratio λ, fin arrangement angle α, and pit width W. d , the ratio of the depth and width of the pit δ d , the width of the convex hull W p , the ratio of the height and width of the convex hull δ p As the size parameter, the layout spacing D is selected as the topological parameter variable, and the objective function is to maximize the average Nusselt number of the liquid cooling pipe wall. The orthogonal test model is constructed. The orthogonal test table is shown in Table 8. After solving, the pipeline scheme with the best performance is obtained;

[0116] Table 8 Orthogonal test table of fin-pit-bulge alternate straight line arrangement

[0117]

[0118]

[0119] The verification part is the same as Example 2.

[0120] The present application is not limited to the above examples, on the basis of the technical solutions disclosed in the present application, those skilled in the art can make some substitutions and deformations to some technical features according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present application.

Claims

1. A method for optimizing the cooling performance of a power battery liquid cooling plate, characterized in that: The following steps are involved: Step 1: Calculate the estimated heat dissipation requirements of the power battery pack and determine the size range of the liquid cooling pipes inside the liquid cooling plate and the outer dimensions of the liquid cooling plate; Step 2: Determine the topology of the liquid cooling circuit, use the size parameters and topological position parameters of each section of the liquid cooling plate pipeline as variables, build a first optimization model, and use this first optimization model to obtain the smooth pipeline solution with the best performance; Step 3: Using the optimal smooth pipe solution obtained in Step 2 as the initial solution, a combination of heat transfer enhancement units is arranged on the pipe wall. Using the heat transfer enhancement unit type and unit combination as variables, a second optimization model is constructed. This second optimization model is used to obtain the heat transfer enhancement unit combination solution with the best performance. The heat transfer enhancement unit is used to represent pits, convex hulls, fins and vortex generators with various shapes that can achieve turbulence enhancement; Step 4: Using the optimal smooth pipeline solution obtained in step 2 as the initial solution, adopting the optimal enhanced heat transfer unit combination solution obtained in step 3, and using the geometric dimensions of the enhanced heat transfer unit monomer and the arrangement dimensions of the unit combination as variables, construct a third optimization model, and use the third optimization model to obtain the pipeline solution with the optimal cooling performance of the power battery liquid cooling plate.

2. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: Calculate the estimated heat dissipation demand of the power battery pack in step 1, select an RC equivalent circuit model to build a power battery model, then use HPPC experiments to obtain battery data, and then use parameter identification to obtain model parameters of the RC equivalent circuit model; The calculation method for estimating the heat dissipation demand of the power battery pack is: Where n is the order of the RC equivalent circuit model, R i is the resistance parameter of the high-order RC equivalent circuit model, i=0,1,2,…n, I is the maximum operating current of the RC equivalent circuit model, and S is the safety factor.

3. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In step 3, the heat transfer enhancement unit combination is arranged on the pipe wall, and an alternating linear arrangement of fins and dimples is selected as the heat transfer enhancement unit combination scheme.

4. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In step 3, the enhanced heat transfer unit combination is arranged on the pipe wall, and the fin-convex hull alternating linear arrangement is selected as the enhanced heat transfer unit combination scheme.

5. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In step 3, the heat transfer enhancement unit combination is arranged on the pipeline wall surface, and an alternating straight line arrangement of pits and convex hulls is selected as the heat transfer enhancement unit combination scheme.

6. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In step 3, the heat transfer enhancement unit combination is arranged on the pipe wall surface, and the fin-dimple-convex hull alternating linear arrangement is selected as the heat transfer enhancement unit combination scheme.

7. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In steps 2 to 4, the objective function is to maximize the average Nusselt number of the liquid cooling pipe wall, and the orthogonal test is used to maximize the cooling performance of the liquid cooling plate.

8. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In steps 2 to 4, the cooling performance of each solution and the optimized solution is analyzed using fluid-thermal coupling simulation.

9. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In step 4, when the heat transfer enhancement unit is a pit, the pit width and the ratio of depth to width are selected as optimization variables; Pit width W d The value range is: 0.5W≤W d ≤0.83W, where W is the channel width, the ratio of the depth and width of the pit δ d The value range is: 0.1≤δ d ≤0.

3.

10. The method for optimizing the cooling performance of a power battery liquid cooling plate according to claim 1, characterized in that: In step 4, when the heat transfer enhancement unit is a convex hull, fins, and vortex generators, the incident flow width (i.e., the dimension of the heat transfer enhancement unit perpendicular to the flow direction) and the ratio of depth to width are selected as optimization variables; When the heat transfer enhancement unit arranged in the upstream area is a pit, the width of the heat transfer enhancement unit is in the range of: 1.2W d ≤W p ≤W, where W d is the width of the pit, W is the width of the flow channel, W p is the width of the convex hull; For other working conditions, the width of the heat transfer enhancement unit is in the range of 0.5W≤W p ≤W; When the heat transfer enhancement unit is a convex hull, the ratio of its height to width δ p The value range is 0.1 to 0.3.

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