Weight reduction method for energy storage module box

Abstract

The invention discloses a weight reduction method of an energy storage module box body, which comprises the following steps of: constructing a three-dimensional geometric model and a finite element analysis model of the energy storage module box body, and on the basis of modal analysis, setting parameters and carrying out iterative solution for multiple times to obtain an optimal space node combination, so that the shape and lightweight design of a liquid cooling plate supporting structure is realized; not only is the design efficiency improved, but also the optimality of the design is ensured; by searching the supporting position and the optimal shape of the liquid cooling plate supporting structure, it is ensured that the structural performance is not affected while the weight is reduced, and therefore the overall stability and durability of the energy storage module box are improved; the analysis shows that the upper box cover is not stressed in the structure, and a modified composite material is adopted to replace a traditional metal material, so that the weight of the upper box cover is reduced by 75%, the overall weight of the energy storage module box body is reduced by 30%, the cost is reduced by 15%, and the modified composite material is easier to design heat dissipation hole channels, the heat dissipation efficiency of the box body is improved, and stable operation of the energy storage module is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a method for reducing the weight of an energy storage module box. Background Art

[0002] As a research and development focus in the new energy field, efficient, long-term and low-cost energy storage technology can achieve efficient storage and release of energy when renewable energy generation is unstable and grid load demand does not match, thereby ensuring the stable operation of the grid.

[0003] In the research and development, production and application of energy storage systems, the design of the energy storage module box, as a key component that carries the battery cells, is of vital importance. Currently, most energy storage module boxes use metal structural parts. The existing problems include: the use of metal structural parts leads to the heavy weight of the energy storage module box, which brings inconvenience to production, transportation and construction; the high processing cost of metal materials increases the overall cost of the energy storage system; the heavy box design limits the installation speed and flexibility of the energy storage module, and reduces construction efficiency.

[0004] To solve the problem of the weight of the energy storage module box, the existing weight reduction methods mainly rely on empirical design and simplified mechanical calculations, which often require multiple iterations and physical prototype testing, resulting in a long R&D cycle and low efficiency. In addition, simplified mechanical calculations cannot accurately predict the performance of the box under complex working conditions, which may lead to insufficient optimization of the design or safety hazards. In addition, due to the uncertainty of the design, cost control becomes complicated and it is difficult to achieve effective cost reduction. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for reducing the weight of an energy storage module box.

[0006] In order to have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended to be a general review, nor is it intended to identify key / important components or to delineate the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a preface to the detailed description that follows.

[0007] The present invention adopts the following technical solution:

[0008] The present invention provides a method for reducing the weight of an energy storage module box, comprising the following steps: constructing a three-dimensional geometric model of the energy storage module box and performing finite element analysis; according to the results of the finite element analysis, identifying high stress areas and material redundant parts in the structure, and performing morphology optimization and lightweight design to determine the support position of the liquid cooling plate support structure, and analyzing that the upper box cover is not subjected to stress, and using modified composite materials instead of metal materials.

[0009] Furthermore, the process of constructing a three-dimensional geometric model of the energy storage module box and performing finite element analysis includes the following steps: dividing the energy storage module box into an upper box cover and a liquid cooling plate support structure according to design requirement data, and establishing a three-dimensional geometric model of the energy storage module box; flattening the established three-dimensional geometric model; meshing based on the three-dimensional geometric model after the flattening, and performing finite element analysis on the model to obtain box analysis result data.

[0010] Furthermore, when establishing the three-dimensional geometric model of the energy storage module box, the external structure of the energy storage module box is divided into two parts: the upper box cover and the liquid cooling plate support structure; for the internal structure of the energy storage module box, the 2D model is obtained by extracting the middle surface, and the shell unit is used for simulation.

[0011] Furthermore, the shape optimization and lightweight design are performed by setting parameters and solving the problem based on modal analysis, and obtaining the best spatial node combination through multiple iterations.

[0012] Furthermore, setting parameters based on modal analysis refers to performing modal analysis and force analysis on the liquid cooling plate support structure, setting the size of the minimum area in the optimization result to 50 mm, giving the minimum thickness of the design variable to 3 mm, giving the maximum thickness of the modified composite material to 20 mm, and setting the optimization result to be symmetrically distributed about the front, back, left and right, with +45° and -45° having the same distribution shape.

[0013] Furthermore, the solving and obtaining the best spatial node combination after multiple iterations refers to that the Optistruct software obtains the design elements, and the nodes in the design space undergo displacement fluctuations in a certain direction according to the optimization algorithm. After 6 iterations, the optimization converges to obtain the best spatial node combination, and the position and shape of the reinforcement ribs in the liquid cooling plate support structure are determined by the moved nodes.

[0014] Furthermore, the modal analysis and solution of the liquid cooling plate support structure are performed. During the force analysis, the stiffness and modal frequency of the liquid cooling plate support structure are improved by finding the position and shape of the sheet metal reinforcement ribs, the direction of the reinforcement ribs is selected to be perpendicular to the surface of the energy storage module box and upward, and the size optimization method is used to determine the optimal structural thickness.

[0015] The beneficial effects brought by the present invention are:

[0016] 1. Based on modal analysis, the present invention obtains the best spatial node combination by setting parameters and performing multiple iterations to achieve the morphology and lightweight design of the liquid cooling plate support structure, which not only improves the design efficiency but also ensures the optimality of the design;

[0017] 2. By finding the support position and optimal shape of the liquid cooling plate support structure, it is ensured that the structural performance is not affected while reducing the weight, thereby improving the overall stability and durability of the energy storage module box;

[0018] 3. By using the three-dimensional model of the box body for stress analysis, it is found that the upper box cover is not subjected to stress in the structure. Therefore, modified composite materials can be used instead of traditional metal materials. By using modified composite materials, the weight of the upper box cover is reduced by 75%, the overall weight of the energy storage module box is reduced by 30%, and the cost is reduced by 15%. In addition, the modified composite materials are easier to design heat dissipation channels, which improves the heat dissipation efficiency of the box body and ensures the stable operation of the energy storage module. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic diagram of an energy storage module box designed by the present invention;

[0021] Figure 2 It is a picture of the three-dimensional geometric model of the constructed energy storage module box;

[0022] Figure 3 This is a picture of the first-order mode shape of the optimized liquid cooling plate support structure;

[0023] Figure 4 This is a picture of the second-order mode shape of the optimized liquid cooling plate support structure;

[0024] Figure 5 This is a picture of the third-order mode shape of the optimized liquid cooling plate support structure;

[0025] Figure 6 This is a picture of the fourth-order mode shape of the optimized liquid cooling plate support structure;

[0026] Figure 7 This is a picture of the fifth-order mode shape of the optimized liquid cooling plate support structure;

[0027] Figure 8 This is a picture of the sixth-order mode shape of the optimized liquid cooling plate support structure;

[0028] Fig. 9 This is a picture of the support status of the liquid cooling plate support structure;

[0029] Fig.10It is the equivalent force shape and distribution cloud diagram of the morphology optimization result;

[0030] Fig.11 It is the force analysis diagram of the energy storage module box. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be clear that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In some illustrative embodiments, Figure 1 As shown, a method for reducing the weight of an energy storage module box is provided, comprising the following steps:

[0033] Based on Hypermesh software, build a 3D geometric model and finite element model of the energy storage module box, and perform finite element analysis;

[0034] Based on the results of finite element analysis, high-stress areas and material redundancy in the structure were identified, and morphology optimization and lightweight design were carried out to determine the support position of the liquid cooling plate support structure. It was analyzed that the upper box cover was not subjected to stress, and modified composite materials were used instead of metal materials.

[0035] Furthermore, the process of constructing a three-dimensional geometric model of the energy storage module box and performing finite element analysis includes the following steps:

[0036] First, according to the design requirements, the energy storage module box is further designed in detail, the energy storage module box is divided into the upper box cover and the liquid cooling plate support structure, and a three-dimensional geometric model of the energy storage module box is established, such as Figure 2 Among them, the design requirements include box weight, box support capacity, waterproof level, thermal conductivity and heat dissipation performance, materials, and box thickness.

[0037] Among them, detailed design refers to reducing the thickness of the box without affecting the supporting force of the energy storage module box, and using cheaper and lighter materials to replace expensive and heavy materials. For example, the thickness of the box where the force is greater is designed to be thicker, and materials with better supporting force are used, such as the base of the box. The hollow part of the base is less stressed and can be made thinner. The upper box cover is not subject to force, so a modified composite material with a higher cost performance can be used.

[0038] Then, the established 3D geometric model is flattened to improve the model mesh quality. Flattening refers to removing unnecessary details, such as small fillets, chamfers, and holes, which may not have a significant impact on the results in finite element analysis, but will increase the complexity of the model.

[0039] Then, based on the flattened three-dimensional geometric model, meshing is performed, a finite element model is built, and a finite element analysis is performed on the model to obtain the box analysis result data. During the meshing process, the appropriate mesh size is defined according to the size of the energy storage module box and the expected analysis accuracy. For key areas, such as stress concentration areas, a smaller mesh size can be set to improve the analysis accuracy. Specifically, since the upper box cover and the liquid cooling plate support structure are relatively simple, quadrilateral units are used in the meshing, and the box is simplified into a rectangular block. The simplified method of connecting rigid body units to the surface of the box is used to restore the contact between the box and the various surfaces of other boxes under various working conditions, thereby improving the accuracy and efficiency of the calculation.

[0040] Before conducting finite element analysis, first define the material properties, including elastic modulus, Poisson's ratio, density, yield strength, etc., based on the actual material of the energy storage module box, and assign the material properties to the corresponding grid units. Then define the boundary conditions, and define fixed constraints, displacement constraints, etc. based on the actual working environment of the energy storage module box to ensure that the boundary conditions can accurately reflect the actual force conditions of the box, and then apply external loads such as gravity, pressure, temperature, etc.

[0041] When establishing the three-dimensional geometric model of the energy storage module box, the external structure of the energy storage module box is divided into two parts: the upper box cover and the liquid cooling plate support structure. Since both the upper box cover and the liquid cooling plate support structure are thin-walled structures, in order to reduce the calculation time of the model, the internal structure of the energy storage module box is obtained by extracting the middle surface, and the shell unit is used for simulation.

[0042] In finite element analysis, shell elements are a type of element used to simulate thin-walled structures. They can effectively simulate the bending, stretching, and shearing behavior of structures. At the same time, compared with solid elements, shell elements require fewer computing resources and have higher computing efficiency. This application ignores the internal structure of the energy storage module box, such as battery cells, circuits, liquid cooling pipes, etc. as 2D and does not include them in the simulation range, thereby reducing the complexity of the model and speeding up the analysis. Accordingly, by simulating key components and structures, the actual performance of the energy storage module box can be more accurately predicted.

[0043] The present invention performs the shape optimization and lightweight design by setting parameters and solving the problem based on modal analysis, and obtaining the best spatial node combination through multiple iterations.

[0044] Among them, setting parameters based on modal analysis means that Optistruct software is used to perform modal analysis and force analysis on the liquid cooling plate support structure, and the size of the minimum area in the optimization result is set to 50 mm. In order to prevent voids caused by the lack of modified composite materials in certain positions of the optimization result, the minimum thickness of the design variable is given to be 3 mm. At the same time, in order to be able to search for the optimal solution in a larger space, the maximum thickness of the modified composite material is given to be 20 mm. In addition, considering the actual force conditions of the box, the optimization results are set to be symmetrically distributed about the front, back, left and right, and +45° and -45° have the same distribution shape.

[0045] Among them, solving and obtaining the best spatial node combination after multiple iterations means that the Optistruct software obtains the design elements, and the nodes in the design space undergo displacement fluctuations in a certain direction according to the optimization algorithm. After 6 steps of iteration, the optimization converges and obtains the best spatial node combination. The position and shape of the stiffeners in the liquid cooling plate support structure are determined by the nodes that move. The thickness distribution of the modified composite material obtained by the 6-step iterative optimization convergence, and the first six modal frequencies of the optimized liquid cooling plate support structure are as follows:

[0046] Order 1 2 3 4 5 6 Modal frequency Hz 131.51 246.98 350.81 462.18 578.75 681.09

[0047] The first six modal vibration shapes of the optimized liquid cooling plate support structure are as follows: Figure 3-8 shown.

[0048] The modal analysis of the liquid cooling plate support structure is solved. During the force analysis, the stiffness and modal frequency of the liquid cooling plate support structure are improved by finding the position and shape of the sheet metal reinforcement ribs. The direction of the reinforcement ribs is selected to be vertical to the surface of the energy storage module box and upward, and the size optimization method is used to determine the optimal structural thickness.

[0049] Morphology optimization has great advantages in improving the modal frequency of structures. Compared with other optimization methods, it takes less time to solve and basically does not change the quality of the structure. It only achieves the optimization goal by allocating reasonable rib shapes and positions, and has lower requirements for manufacturing processes.

[0050] According to the requirements of the design space, the installation of the energy storage module box and the internal battery cell distribution are comprehensively considered, and the direction of the reinforcing ribs is selected to be vertical to the box surface upward; the main purpose of the morphology optimization is to increase the low-order modal frequency of the liquid cooling support plate structure, maximize the optimization target, and achieve the best morphology and force strength of the liquid cooling plate support structure. The optimal support state, such as Fig. 9 shown.

[0051] The morphology and size of the liquid cooling support plate structure are optimized by Optistruct. Based on modal analysis, the first-order modal frequency is increased, relevant parameters are set, and solution calculations are performed. After multiple iterations, the objective function converges, and the equivalent force shape and distribution cloud diagram are as follows: Fig.10 As shown in the figure, lightweight design is carried out based on random vibration and static strength conditions, and the optimization results are integrated and verified.

[0052] According to the stress analysis of the three-dimensional modeling of the energy storage module box, the upper box cover is not the main load-bearing structure in the structure, so a modified composite material with a high cost performance ratio is used. In order to achieve the purpose of lightweighting, the morphology optimization method is used to find the position of the reinforcement ribs to increase the modal frequency of the liquid cooling support plate structure, and then the size optimization method is used to determine the optimal structural thickness.

[0053] Since a group of energy storage module boxes are arranged between the layers of liquid cooling plates, the liquid cooling plates of the next layer completely support the energy storage module boxes, and there is a certain gap between the liquid cooling plates of the upper layer and the energy storage module boxes. According to the layout structure design of the battery cluster and the liquid cooling plates, the upper part of the energy storage module boxes is not subject to force.

[0054] In the simulation calculation of the energy storage module box, the battery module does not deform, and it is sufficient to ensure that the mass distribution and load transfer path are consistent with the actual situation. Therefore, the battery module is simulated by a hexahedral mesh with an average unit size of 15mm. The thickness of the upper box of the original energy storage module box is 3mm, and the thickness of the lower box bottom plate is 5mm. In order to simulate the force effect on the battery module, corresponding loads are applied to all unit nodes of the battery module. The load value can be based on the value of the force point tested on the sample equipment box. When modeling, each grid point has a corresponding force point, and the force value of the force point is tested. After the model obtains these force values, a force analysis diagram is obtained, such as Fig.11 As shown, the sides and top are almost unstressed, so cost-effective modified composite materials can be used.

[0055] The energy storage module box weight reduction method of the present invention realizes the lightweight of the box structure and improves the rigidity of the components through modeling analysis and optimization design, and has the following beneficial effects:

[0056] Efficient modeling and analysis of the box: By decomposing the 3D geometric model of the energy storage module box into different components, such as the upper box cover and the liquid cooling plate support structure, more efficient modeling and analysis can be performed. This component-by-component approach not only simplifies the analysis process, but also improves the accuracy of the analysis, laying a solid foundation for subsequent optimization design;

[0057] Shape optimization design method: The shape optimization design method of the present invention significantly improves the rigidity of the component by finding the support position and optimal shape of the liquid cooling plate support structure. This optimization design ensures that the structural performance is not affected while reducing the weight, thereby improving the overall stability and durability of the energy storage module box;

[0058] Modal analysis and iterative design: Based on modal analysis, the present invention obtains the best spatial node combination by setting parameters and performing multiple iterative solutions. This method realizes the morphology and lightweight design of the liquid cooling plate support structure, which not only improves the design efficiency but also ensures the optimality of the design.

[0059] Replacement and lightweighting of the upper box cover material: Utilizing the three-dimensional model stress analysis of the box body, the present invention finds that the upper box cover is not subjected to stress in the structure, and therefore a modified composite material can be used instead of the traditional metal material, thereby achieving the following significant effects: The upper cover is reduced in weight by 75%. By using the modified composite material, the weight of the upper box cover is greatly reduced, thereby reducing the weight of the entire box body; the box body is reduced in weight by 30%. The overall weight reduction not only improves the convenience of handling and installation, but also reduces transportation costs; the heat dissipation performance is improved. The modified composite material makes it easier to design heat dissipation channels, thereby improving the heat dissipation efficiency of the box body and ensuring the stable operation of the energy storage module; the cost is reduced by 15%. The use of modified composite materials instead of metal materials not only reduces weight, but also reduces material and production costs, thereby improving the market competitiveness of the product.

[0060] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for reducing the weight of an energy storage module box, characterized in that: The steps include: Construct a three-dimensional geometric model of the energy storage module box and perform finite element analysis; Based on the results of finite element analysis, high-stress areas and material redundancy in the structure were identified, and morphology optimization and lightweight design were carried out to determine the support position of the liquid cooling plate support structure. It was analyzed that the upper box cover was not subjected to stress, and modified composite materials were used instead of metal materials.

2. A method for reducing the weight of an energy storage module box according to claim 1, characterized in that: The process of constructing a three-dimensional geometric model of the energy storage module box and performing finite element analysis includes the following steps: According to the design requirements, the energy storage module box is divided into an upper box cover and a liquid cooling plate support structure, and a three-dimensional geometric model of the energy storage module box is established; Flatten the established three-dimensional geometric model; Meshing is performed on the basis of the flattened three-dimensional geometric model, and finite element analysis is performed on the model to obtain the box analysis result data.

3. A method for reducing the weight of an energy storage module box according to claim 2, characterized in that: When establishing the 3D geometric model of the energy storage module box, the external structure of the energy storage module box is divided into two parts: the upper box cover and the liquid cooling plate support structure. For the internal structure of the energy storage module box, the 2D model is obtained by extracting the middle surface, and the shell unit is used for simulation.

4. A method for reducing the weight of an energy storage module box according to claim 3, characterized in that: The shape optimization and lightweight design are performed by setting parameters and solving the problem based on modal analysis, and obtaining the best spatial node combination through multiple iterations.

5. A method for reducing the weight of an energy storage module box according to claim 4, characterized in that: The parameter setting based on modal analysis refers to performing modal analysis and force analysis on the liquid cooling plate support structure, setting the size of the minimum area in the optimization result to 50 mm, the minimum thickness of the given design variable to 3 mm, the maximum thickness of the given modified composite material to 20 mm, and setting the optimization result to be symmetrically distributed about the front, back, left and right, with +45° and -45° having the same distribution shape.

6. A method for reducing the weight of an energy storage module box according to claim 5, characterized in that: The solving and obtaining the best spatial node combination after multiple iterations means that the Optistruct software obtains the design elements, and the nodes in the design space undergo displacement fluctuations in a certain direction according to the optimization algorithm. After 6 iterations, the optimization converges and the best spatial node combination is obtained. The position and shape of the reinforcement ribs in the liquid cooling plate support structure are determined by the moved nodes.

7. A method for reducing the weight of an energy storage module box according to claim 6, characterized in that: The modal analysis and solution of the liquid cooling plate support structure are performed. In the force analysis, the stiffness and modal frequency of the liquid cooling plate support structure are improved by finding the position and shape of the sheet metal reinforcement ribs, the reinforcement rib direction is selected to be vertical to the surface of the energy storage module box and upward, and the size optimization method is used to determine the optimal structural thickness.

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