Energy storage cell housing and design and manufacturing process thereof

Abstract

This invention relates to the field of energy storage battery technology, specifically disclosing an energy storage cell housing and its design and manufacturing process, comprising: a lower housing with an opening at its top, the diameter of which is smaller than the inner diameter of the lower housing; an annular connecting plate formed at the top of the lower housing; and an upper cover disposed on top of the lower housing, the middle of which is higher than its edge, the upper cover and the annular connecting plate of the lower housing being connected by overlapping welding for sealing. By replacing the materials in the original solution with high-strength, low-thickness, highly corrosion-resistant, and highly machinable materials, the goal of lightweight design and increased energy density per unit mass is achieved; the structural design improvements of the upper cover and lower housing, as well as the use of overlapping welding for sealing, can improve the mechanical strength and structural rigidity of the product, and reduce the fitting precision requirements of the upper cover and lower housing.

Description

Technical Field

[0001] This invention relates to the field of energy storage battery technology, and more specifically, to an energy storage cell housing and its design and manufacturing process. Background Technology

[0002] Currently, based on the explosive growth in demand in the energy storage market and the continuous iteration and innovation of energy storage battery raw material technology, the different working scenarios have placed higher demands on the material performance, product structure, processing technology, connection technology, and lightweighting of the battery cell casing.

[0003] The existing liquid energy storage cell casing uses conventional SUS304 stainless steel with a thickness of ≥2.0mm. The product structure adopts a "stepped" docking connection between a cylindrical lower shell and a circular flat upper cover. The forming process uses cold stamping and CNC (computer numerical control) cross-section machining. The connection process uses laser self-fusion welding for sealing. Due to the relatively low strength of the material, the product design chooses to increase the material thickness to meet the working strength requirements.

[0004] The existing liquid energy storage cell casings still have the following problems: 1. The top cover is usually made of a 3mm thick circular plate, made of SUS304 (the Japanese material standard for 304 stainless steel) stainless steel (material yield strength ≥250MPa, tensile strength ≥515 MPa). The product is not lightweight enough and has a simple planar shape. During the high temperature and high pressure operation of the battery cell, the top cover is prone to axial deformation. 2. The lower shell is typically made of 2mm thick SUS304 stainless steel. The lower shell features a U-shaped cylindrical structure and is formed using cold stamping. After forming, springback easily occurs at the top of the U-shaped opening, resulting in significant variations in the roundness, concentricity, and end-face runout between batches, leading to poor accuracy in diameter and height dimensions. To ensure the design and assembly dimensions of the lower shell, the product requires end-face turning in the height direction after cold stamping. End-face machining results in runout and dimensional fluctuations. During the machining of the stepped surface, stress concentration occurs at the corners of the steps, and there are also fluctuations in the thickness tolerance of the steps, affecting the product's fatigue strength. 3. The connection process between the upper cover and the lower shell currently adopts a "stepped" type butt laser welding process. The laser welding process requires the "stepped" butt gap to be ≤0.3mm. During the processing of the lower shell, dimensional fluctuations will occur, causing fluctuations in the fit gap between the upper cover and the lower shell, which will affect the laser welding strength, resulting in uneven distribution of the welding heat-affected zone. Ultimately, this will affect the fatigue life of the product under mass production working conditions, leading to potential risks of unstable welding quality, and ultimately affecting the sealing quality and service life of the product. 4. The choice of materials, thickness, and structural design directly affect the improvement of energy density of energy storage cells.

[0005] Therefore, it is necessary to propose an energy storage cell housing and its design and manufacturing process to at least partially solve the problems existing in the prior art. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] To at least partially solve the above problems, the present invention provides an energy storage cell housing, comprising: The lower housing has an opening at its top, the diameter of which is smaller than the inner diameter of the lower housing; the top of the lower housing forms an annular connecting plate. An upper cover is disposed on top of the lower housing, with the middle of the upper cover being higher than its edge. The upper cover and the annular connecting plate of the lower housing are connected by overlapping welding for sealing.

[0008] Preferably, the upper cover includes: A central pressure plate, with its middle section higher than its edges; An edge connecting plate is disposed on the outside of the central bearing plate, and the edge connecting plate and the annular connecting plate are connected by overlapping welding for sealing.

[0009] Preferably, the central bearing plate has an upwardly convex curved surface structure.

[0010] Preferably, the central bearing plate includes a central area and a transition area arranged sequentially from the inside out, wherein the transition area has a curved surface structure.

[0011] Preferably, the upper cover is provided with a first reinforcing rib, which is radially distributed.

[0012] Preferably, the first reinforcing rib is disposed in the transition zone.

[0013] Preferably, the first reinforcing rib forms a recessed area on the top surface of the upper cover and a protruding part on the bottom surface of the upper cover.

[0014] Preferably, the bottom of the lower housing is provided with a radial second reinforcing rib and a circumferential third reinforcing rib, wherein the second reinforcing rib is radially distributed.

[0015] A design and manufacturing process for an energy storage cell casing includes: S1. The upper cover is made by cold stamping, so that the middle of the upper cover is higher than its edge. The lower shell is made by cold stamping, rotary cutting, spinning and flanging, so that the top of the lower shell forms a ring connecting plate. S2. Position and stack the upper cover on the annular connecting plate of the lower shell, and weld the upper cover to the annular connecting plate using laser filler wire welding or argon arc welding.

[0016] Preferably, before step S1, the method further includes: Functional simulation tools were used to verify the structural strength and stiffness of the upper cover and lower shell under normal working conditions, so as to optimize the structure of the upper cover and lower shell. Feasibility analysis and risk point optimization of the molding process of the upper cover and lower shell were carried out using molding process simulation tools to obtain optimized molding process parameters for the upper cover and lower shell. Welding deformation simulation tools were used to simulate the feasibility of the welding process and the amount of welding deformation of the upper cover and lower shell, so as to obtain optimized welding process parameters.

[0017] Preferably, the structural strength includes: the material equivalent stress of the upper cover and the lower shell, and the equivalent stress at the welding position; The structural stiffness includes the deformation of the upper cover and the lower shell.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: The energy storage cell housing and its design and manufacturing process described in this invention achieve lightweight design and improved energy density per unit mass by replacing the materials in the original scheme with high-strength, low-thickness, high-corrosion-resistant, and high-machinability materials; the improved structural design of the upper cover and lower housing, as well as the use of overlapping welding and sealing connection, can improve the mechanical strength and structural rigidity of the product. The lower shell adopts traditional cold stamping, rotary cutting, spinning and flanging processes to meet specifications, satisfy product performance, reduce product processing difficulty, improve product processing efficiency and reduce product process costs. The sealing connection between the upper cover and the lower shell adopts a lap welding structure design, which can reduce the fitting accuracy requirements of the upper cover and the lower shell. During welding, laser filler wire welding or argon arc welding is used instead of laser self-fusion welding, which improves the first-pass yield of welding seal and fatigue strength, and reduces the quality fluctuation risk of the original welding process.

[0019] The energy storage cell housing and its design and manufacturing process described in this invention, as well as other advantages, objectives and features of this invention, will be partly apparent from the following description and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of an energy storage cell casing in the prior art; Figure 2 This is a schematic diagram of the cross-sectional structure of the lower shell in the prior art; Figure 3 This is an exploded structural diagram of the energy storage cell housing described in this invention; Figure 4 This is a schematic cross-sectional view of the energy storage cell housing described in this invention. Figure 5 This is a schematic diagram of the external structure of the energy storage cell housing described in this invention; Figure 6 This is a schematic diagram of the welded joint between the upper cover and the lower shell in the energy storage cell housing of the present invention; Figure 7 This is a top view of the upper cover of the energy storage cell housing described in this invention. Figure 8 This is a schematic cross-sectional view of the upper cover of the energy storage cell housing described in this invention. Figure 9 This is a schematic diagram of another structure of the energy storage cell housing described in this invention; Figure 10 This is a front view schematic diagram of another structure of the energy storage cell housing described in this invention; Figure 11 for Figure 10 Schematic diagram of the cross-sectional structure at point AA; Figure 12 This is a schematic diagram of the lower housing of another structure of the energy storage cell housing described in this invention; Figure 13 This is a flowchart illustrating the design and manufacturing process of the energy storage cell housing described in this invention.

[0021] In the attached drawings, 1 is the lower shell, 11 is the opening, 12 is the annular connecting plate, 13 is the second reinforcing rib, 14 is the third reinforcing rib, 2 is the upper cover, 21 is the central bearing plate, 211 is the central area, 212 is the transition area, 22 is the edge connecting plate, 23 is the first reinforcing rib, 10 is the upper cover, 20 is the lower shell, and 30 is the stepped surface. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description.

[0023] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0024] like Figures 1-2 As shown, the upper cover 10 and lower shell 20 are from the prior art. The upper cover 10 is a circular flat plate structure, and the lower shell 20 is a "U"-shaped structure. The top of the lower shell 20 has a "stepped" surface corresponding to that of the upper cover 10. Figure 2 The stepped surface 30 shown in the figure; the present invention improves the structure of the upper cover 10 and the lower shell 20 to solve the problems existing in the prior art.

[0025] like Figures 3-4 As shown, the present invention provides an energy storage cell housing, comprising: The lower housing 1 has an opening 11 at its top, the diameter of which is smaller than the inner diameter of the lower housing 1; an annular connecting plate 12 is formed at the top of the lower housing 1. The upper cover 2 is disposed on the top of the lower housing 1. The middle part of the upper cover 2 is higher than its edge. The upper cover 2 and the annular connecting plate 12 of the lower housing 1 are connected by overlapping welding for sealing.

[0026] The lower shell 1 and upper cover 2 can be replaced with stainless steel materials with higher strength and equivalent corrosion resistance and processing performance to SUS304. For example, high-strength austenitic stainless steel can be strengthened by adding nitrogen for solid solution strengthening, and can achieve higher strength after cold working while maintaining excellent corrosion resistance and formability and weldability. This allows for a reduction in the thickness of the product material. The thickness of the upper cover 2 can be reduced from 3mm to 1.5mm~2mm, and the thickness of the lower shell 1 can be reduced from 2mm to 1.5mm~2mm, thereby reducing the weight of the product and increasing the energy density per unit mass (the energy that can be stored per unit mass of material, usually used to evaluate the performance of energy storage devices such as batteries). The upper cover 2 is designed so that the middle part is higher than its edge, which can improve the resistance of the upper cover 2 to the axial force of the high pressure inside the working chamber. The upper cover 2 and the lower shell 1 are connected by overlapping welding and sealing. From the structural design, the fitting accuracy requirements of the upper cover 2 and the lower shell 1 can be reduced, and the processing difficulty and cost can be reduced.

[0027] Through the above design, by replacing the materials in the original scheme with high-strength, low-thickness, high-corrosion-resistant, and high-machinability materials, the goals of lightweight design and increased energy density per unit mass are achieved; the structural design improvements of the upper cover 2 and the lower shell 1, as well as the use of overlapping welding sealing connection, can improve the mechanical strength and structural rigidity of the product.

[0028] like Figures 5-6 As shown, in one embodiment, the upper cover 2 includes: The central pressure plate 21 is positioned with its middle section higher than its edge; An edge connecting plate 22 is disposed on the outside of the central bearing plate 21, and the edge connecting plate 22 and the annular connecting plate 12 are connected by overlapping welding for sealing.

[0029] The central bearing plate 21 is mainly used to bear the high pressure inside the upper cover 2 during operation. The edge connecting plate 22 is used to overlap with the annular connecting plate 12 and then be sealed by overlapping welding. For example, laser filler wire welding or argon arc welding can be used to weld, thereby replacing laser self-fusion welding and improving the sealing performance.

[0030] The central bearing plate 21 provides the following possible solutions: The first type is a curved structure with an upward convex shape, where the central pressure plate 21 is a central pressure plate.

[0031] The central pressure plate 21 has an upwardly convex curved surface structure, such as a spherical dome structure, to resist the axial force of the high pressure inside the working chamber.

[0032] The second type, such as Figures 7-8 As shown, the central pressure plate 21 includes a central area 211 and a transition area 212 arranged sequentially from the inside to the outside, and the transition area 212 has a curved surface structure.

[0033] The central area 211 can be a planar structure, while the transition area 212 is a curved structure, which facilitates the installation of other accessories in the central area 211.

[0034] like Figure 5 As shown, in one embodiment, the upper cover 2 is provided with a first reinforcing rib 23, which is radially distributed.

[0035] The first reinforcing rib 23 is radially distributed from the center of the upper cover 2 outwards to better resist the axial force of the high pressure inside the upper cover 2 during operation.

[0036] like Figure 7 As shown, in one embodiment, the first reinforcing rib 23 is disposed in the transition region 212.

[0037] In the second embodiment of the central bearing plate 21, the first reinforcing rib 23 is arranged in the transition zone 212; The first reinforcing rib 23 may be distributed radially; Alternatively, the first reinforcing rib 23 can be further reinforced with annular ribs on the radial basis to resist both radial and axial forces. Alternatively, the first reinforcing rib 23 may be a spiral rib extending from the center to the outer edge, which can effectively transmit and disperse torque or asymmetric loads.

[0038] like Figure 3As shown, in one embodiment, the first reinforcing rib 23 forms a recessed area on the top surface of the upper cover 2 and a protrusion on the bottom surface of the upper cover 2.

[0039] When the upper cover 2 is formed by cold stamping, the first reinforcing rib 23 is formed simultaneously, which effectively reduces the thickness of the upper cover 2 while ensuring the upper cover 2's ability to withstand working internal pressure.

[0040] like Figures 9-12 As shown, another structure of the energy storage cell housing is provided. Unlike the structure of the aforementioned energy storage cell housing, the bottom of the lower housing 1 is also provided with a radial second reinforcing rib 13 and a circumferential third reinforcing rib 14. The second reinforcing rib 13 is radially distributed.

[0041] Because the bottom of the lower housing 1 is prone to axial deformation during the high temperature and high pressure operation of the battery cell, radial and circumferential reinforcing ribs are added to the bottom of the lower housing 1 to resist deformation and improve the mechanical strength of the product. Among them, such as Figure 12 As shown, a third reinforcing rib 14 is arranged between each of the two adjacent second reinforcing ribs 13. The third reinforcing rib 14 is an arc-shaped rib and is concentrically arranged with the bottom of the lower shell 1. The second reinforcing rib 13 and the third reinforcing rib 14 can be formed by cold stamping process, forming a recessed area on the outer bottom surface of the lower shell 1 and a protruding part on the inner bottom surface of the lower shell 1, so as to improve the deformation resistance of the bottom of the lower shell 1.

[0042] like Figure 13 As shown, the present invention also provides a design and manufacturing process for an energy storage cell housing, including: S1. The upper cover 2 is made by cold stamping process, so that the middle part of the upper cover 2 is higher than its edge. The lower shell 1 is made by cold stamping process and one or more of rotary cutting, spinning and flanging processes, so that the top of the lower shell 1 forms an annular connecting plate 12. S2. Position the upper cover 2 on the annular connecting plate 12 of the lower shell 1, and weld the upper cover 2 onto the annular connecting plate 12 using laser filler wire welding or argon arc welding.

[0043] The upper cover 2 is formed by cold stamping to create a structure in the middle that is higher than its edges. At the same time, a first reinforcing rib 23 is formed on the upper cover 2 to enhance the upper cover 2's resistance to the axial force of the high pressure inside the working chamber. The cold stamping process is a processing method that uses a die to apply pressure to a metal material at room temperature, causing it to deform or separate, thereby obtaining the required shape and size. The lower shell 1 is first manufactured using a cold stamping process, and then the annular connecting plate 12 and the opening 11 are manufactured using one or more of the following processes: rotary cutting, spinning, and flanging. Among them, rotary cutting is a processing method that cuts the blank by rotating a tool; spinning is a process in which the blank is placed on a spinning machine and bent, stretched and squeezed by rotational pressure to obtain a metal part of the desired shape, thereby closing the lower shell 1; flanging is a process in which the edge of the blank is folded to form a vertical edge, usually on the flat or curved part of the blank, using the action of a mold to form a straight wall or flange with a certain angle along the closed or unclosed curved edge. After the upper cover 2 and the lower shell 1 are manufactured, the upper cover 2 is placed on the lower shell 1, ensuring that the edge connecting plate 22 of the upper cover 2 overlaps with the annular connecting plate 12 of the lower shell 1. Then, welding is performed using laser filler wire welding or argon arc welding. Laser filler wire welding uses a high-power laser beam focused on the parts of the upper cover 2 and the lower shell 1 to be welded, forming a molten pool. At the same time, the metal welding wire is precisely fed into the molten pool, and the metal welding wire is melted by the molten pool to become the filler metal of the weld. Argon arc welding uses an inert gas as a protective medium and uses the high temperature of the electric arc to melt the parts of the upper cover 2 and the lower shell 1 to be welded and the metal welding wire. After the molten metal cools and solidifies, it forms a weld.

[0044] Using the above methods, the dimensional accuracy of the lower shell 1 does not need to be guaranteed by precision machine tool processing. Traditional cold stamping, rotary cutting, spinning and flanging processes can meet the specifications, satisfy product performance, reduce the processing difficulty, improve the processing efficiency and reduce the product process cost. The sealing connection between the upper cover 2 and the lower shell 1 adopts a lap welding structure design, which can reduce the fitting accuracy requirements of the upper cover 2 and the lower shell 1. During welding, laser filler wire welding or argon arc welding is used instead of laser self-fusion welding, which improves the first-pass yield of welding seal and fatigue strength, and reduces the quality fluctuation risk of the original welding process.

[0045] In one embodiment, prior to step S1, the method further includes: Functional simulation tools were used to verify the structural strength and stiffness of the upper cover 2 and the lower shell 1 under normal working conditions, so as to optimize the structure of the upper cover 2 and the lower shell 1. Feasibility analysis and risk point optimization of the molding process of the upper cover 2 and the lower shell 1 were carried out using molding process simulation tools to obtain optimized molding process parameters for the upper cover 2 and the lower shell 1. Welding deformation simulation tools were used to simulate the feasibility of the welding process and the amount of welding deformation of the upper cover 2 and the lower shell 1 in order to obtain optimized welding process parameters.

[0046] The structural strength includes: the material equivalent stress of the upper cover 2 and the lower shell 1 and the equivalent stress at the welding position; The structural stiffness includes the deformation of the upper cover 2 and the lower shell 1.

[0047] The functional simulation tool, molding process simulation tool, and welding deformation simulation tool all use CAE simulation tools to optimize the structure, molding process parameters, and welding process parameters of the upper cover 2 and the lower shell 1, respectively, in order to improve the mechanical structural strength and structural rigidity of the product, ensure welding quality, and improve processing efficiency and product qualification rate.

[0048] Furthermore, optimizing the structure of the upper cover 2 using functional simulation tools includes: An initial parametric three-dimensional model of the upper cover 2 is established. The variables defined in the initial parametric three-dimensional model include at least the curvature parameters of the central bearing plate 21 of the upper cover 2, the distribution parameters of the first reinforcing rib 23, and the thickness parameters of each region of the upper cover 2. The initial parametric three-dimensional model was subjected to internal pressure loads under normal working conditions and finite element analysis was performed to obtain the initial performance data of its structural strength and structural stiffness. The initial performance data includes: the maximum equivalent stress value of the initial parametric three-dimensional model, the location of the maximum equivalent stress, and the center displacement of the central bearing plate 21; Based on the initial performance data, the curvature parameters are adjusted and iterative simulations are performed to obtain the first optimized parametric 3D model. The parametric three-dimensional model after the first optimization is subjected to internal pressure load under normal working conditions and finite element analysis is performed to obtain its principal stress direction and stress distribution cloud map. Based on the principal stress direction and stress distribution cloud map, the distribution parameters of the first stiffener 23 are optimized and the layout is designed to obtain the parametric three-dimensional model after the second optimization. The parametric 3D model after the second optimization was subjected to internal pressure load under normal working conditions and finite element analysis was performed to obtain its stress distribution cloud map and strain energy distribution cloud map. Based on the stress distribution cloud map and strain energy distribution cloud map, the thickness parameters of each region of the upper cover 2 were adjusted to obtain the parametric 3D model after the third optimization. Among them, the local thickness of the region identified as high stress or high strain energy in the stress and strain energy distribution cloud map was increased, and the local thickness of the region identified as low stress or low strain energy was decreased. The parametric 3D model after the third optimization is re-analyzed using finite element analysis to obtain its optimized performance data. If the optimized performance data does not meet the preset structural strength threshold and preset structural stiffness threshold, iterative optimization is performed until a parametric 3D model that simultaneously meets the preset structural strength threshold, preset structural stiffness threshold, and optimal lightweight objective is obtained. The optimized performance data includes: the maximum equivalent stress value, the location of the maximum equivalent stress, and the center displacement of the central bearing plate 21 of the parametric 3D model after the third optimization.

[0049] Among them, the curvature parameter is the radius of curvature of the central bearing plate 21, or is defined as the coordinates of the control point of the non-spherical continuous surface; the distribution parameters of the first reinforcing rib 23 are the number of the first reinforcing ribs 23, the starting position, and the radial angle distribution (the included angle between adjacent first reinforcing ribs 23); the thickness parameter of the upper cover 2 is the thickness value of each region, and the initial thickness value is 1.5mm.

[0050] The above method achieves optimal material distribution in space by coordinating the curvature parameters of the central bearing plate 21, the distribution parameters of the first reinforcing rib 23, and the thickness parameters of each region of the upper cover 2. This significantly reduces the weight of the upper cover 2 while ensuring structural performance. Through iterative optimization in stages and targeting specific simulation data (maximum stress and deformation), the final model simultaneously meets the requirements of strength and stiffness, ensuring that the upper cover 2 does not yield or deform excessively under internal high pressure conditions. The thickness design directly strengthens high-stress areas and thins low-stress areas, thereby strengthening weak areas and improving fatigue life. The design of the first reinforcing rib 23 based on the principal stress direction and stress distribution cloud map forms an efficient load transfer path, effectively reducing stress concentration.

[0051] Furthermore, optimizing the structure of the lower shell 1 using functional simulation tools includes: Establish an initial parametric three-dimensional model of the lower shell 1. The defined variables of the initial parametric three-dimensional model include at least the distribution parameters of the second stiffener 13 and the third stiffener 14 on the lower shell 1 and the thickness parameters of each region of the lower shell 1. The initial parametric 3D model is subjected to internal pressure loads under normal working conditions and finite element analysis is performed to obtain initial performance data of its structural strength and stiffness, as well as its principal stress direction and stress distribution cloud map. The initial performance data includes: the maximum equivalent stress value of the initial parametric 3D model, the location of the maximum equivalent stress, and the maximum deformation of the bottom of the lower shell 1 (the maximum displacement of the bottom in axial deformation). Based on the principal stress direction and stress distribution cloud map, the distribution parameters of the second stiffener 13 and the third stiffener 14 are optimized and the layout is designed to obtain the parameterized three-dimensional model after the first optimization. Internal pressure loads under normal working conditions were applied to the parameterized three-dimensional model after the first optimization, and finite element analysis was performed to obtain its stress distribution cloud map and strain energy distribution cloud map. Based on the stress distribution cloud map and strain energy distribution cloud map, the thickness parameters of each region of the lower shell 1 were adjusted (multiple regions including: side walls, annular connecting plate 12 and bottom) to obtain the parameterized three-dimensional model after the second optimization. Among them, the local thickness of the regions identified as high stress or high strain energy in the stress and strain energy distribution cloud maps was increased, and the local thickness of the regions identified as low stress or low strain energy was decreased. The parametric 3D model after the second optimization is re-analyzed using finite element analysis to obtain its optimized performance data. If the optimized performance data does not meet the preset structural strength threshold and preset structural stiffness threshold, iterative optimization is performed until a parametric 3D model that simultaneously meets the preset structural strength threshold, preset structural stiffness threshold, and optimal lightweight objective is obtained. The optimized performance data includes: the maximum equivalent stress value, the location of the maximum equivalent stress, and the maximum deformation of the bottom of the lower shell 1 (the maximum displacement of the bottom in the axial direction) of the parametric 3D model after the second optimization.

[0052] The distribution parameters of the second reinforcing rib 13 and the third reinforcing rib 14 are the number of the second reinforcing ribs 13, the starting and ending positions, the radial angle distribution (the included angle between adjacent second reinforcing ribs 13), and the arc length of the third reinforcing rib 14 (the center of the third reinforcing rib 14 is preferably set concentrically with the bottom of the lower shell 1); the thickness parameter of the lower shell 1 is the thickness value of each region (side wall, annular connecting plate 12 and bottom), and the initial thickness value is 1.5mm.

[0053] The above method achieves optimal material distribution in space by synergistically optimizing the distribution parameters of the second stiffener 13 and the third stiffener 14 of the lower shell 1, as well as the thickness parameters of each region of the lower shell 1. While ensuring structural performance, it reduces the weight of the lower shell 1, meets the requirements of strength and stiffness, and ensures that the lower shell 1 does not undergo axial deformation under internal high pressure conditions. The thickness design directly targets the high stress area for strengthening and the low stress area for thinning, thereby improving the fatigue life of the lower shell 1. The design of the second stiffener 13 and the third stiffener 14 based on the principal stress direction and stress distribution cloud map forms an efficient load transfer path and effectively reduces stress concentration.

[0054] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0055] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the present invention, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A battery cell housing, characterized in that, include: The lower housing (1) has an opening (11) at its top, the diameter of which is smaller than the inner diameter of the lower housing (1); an annular connecting plate (12) is formed at the top of the lower housing (1). The upper cover (2) is set on the top of the lower shell (1), with the middle part of the upper cover (2) being higher than its edge, and the upper cover (2) and the annular connecting plate (12) of the lower shell (1) are connected by overlapping welding.

2. The energy storage cell housing according to claim 1, characterized in that, The upper cover (2) includes: A central bearing plate (21) is provided with its middle portion higher than its edge; An edge connecting plate (22) is disposed on the outside of the central bearing plate (21), and the edge connecting plate (22) and the annular connecting plate (12) are connected by overlapping welding.

3. The energy storage cell housing according to claim 2, characterized in that, The central bearing plate (21) is an upwardly convex curved structure.

4. The energy storage cell housing according to claim 2, characterized in that, The central bearing plate (21) includes a central area (211) and a transition area (212) arranged sequentially from the inside to the outside, wherein the transition area (212) is a curved surface structure.

5. The energy storage cell housing according to claim 1, 2, or 4, characterized in that, The upper cover (2) is provided with a first reinforcing rib (23), which is radially distributed.

6. The energy storage cell housing according to claim 5, characterized in that, The first reinforcing rib (23) is located in the transition zone (212).

7. The energy storage cell housing according to claim 1, characterized in that, The bottom of the lower shell (1) is provided with a radial second reinforcing rib (13) and a circumferential third reinforcing rib (14), and the second reinforcing rib (13) is radially distributed.

8. A design and manufacturing process for an energy storage cell housing, used for designing and manufacturing the energy storage cell housing according to any one of claims 1-7, characterized in that, include: S1. The upper cover (2) is made by cold stamping process, so that the middle part of the upper cover (2) is higher than its edge. The lower shell (1) is made by cold stamping process and one or more of rotary cutting, spinning and flanging processes, so that the top of the lower shell (1) forms an annular connecting plate (12). S2. Position the upper cover (2) on the annular connecting plate (12) of the lower shell (1), and weld the upper cover (2) onto the annular connecting plate (12) using laser filler wire welding or argon arc welding.

9. The design and manufacturing process of the energy storage cell housing according to claim 8, characterized in that, Before step S1, the following is also included: The structural strength and structural stiffness of the upper cover (2) and the lower shell (1) under normal working conditions were verified using functional simulation tools in order to optimize the structure of the upper cover (2) and the lower shell (1); Feasibility analysis and risk point optimization of the molding process of the upper cover (2) and the lower shell (1) were carried out using molding process simulation tools to obtain the optimized molding process parameters of the upper cover (2) and the lower shell (1); The feasibility of the welding process and the amount of welding deformation of the upper cover (2) and the lower shell (1) were simulated using a welding deformation simulation tool to obtain optimized welding process parameters.

10. The design and manufacturing process of the energy storage cell housing according to claim 9, characterized in that, The structural strength includes: the material equivalent stress of the upper cover (2) and the lower shell (1) and the equivalent stress at the welding position; The structural stiffness includes the deformation of the upper cover (2) and the lower shell (1).

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