Design method of battery rack fixing structure for ship and battery rack fixing structure

Abstract

The invention discloses a method for designing a battery rack fixing structure for a ship, which comprises the following steps of: determining the corresponding relation between ship navigation working conditions and battery rack stress, defining actual working conditions in longitudinal, transverse and vertical directions in a ship coordinate system in the ship navigation process, and determining the actual working conditions according to data recorded by an acceleration sensor in the ship navigation process. Empirical accelerations in the longitudinal direction, the transverse direction and the vertical direction of the battery module under the working condition are obtained, and stress parameters of the battery rack are calculated; the battery rack fixing structure is disassembled and regarded as three independent cantilever beam structures, and the maximum deflection of cantilever beams under the stress condition is calculated; establishing a constraint equation set, setting a safety coefficient and constraint parameters for bending strength, and establishing an optimized constraint equation; for structural strength, setting a reference size parameter group, and establishing a constraint equation; setting a reference height parameter, and establishing a constraint equation; design parameters of the battery rack fixing structure are calculated and determined, and the actual requirement for fixing the battery module is met.

Description

Technical Field

[0001] This invention relates to the field of marine battery rack structure technology, specifically to a design method and fixing structure for a marine battery rack. Background Technology

[0002] Lithium-ion batteries, with their advantages of high energy density and long cycle life, have been gradually applied to marine power systems, becoming a core energy storage component in the development of electric ships. Unlike land-based applications, ships face complex and variable operating conditions during navigation, and marine batteries are typically characterized by high power and large weight, which places stringent requirements on the fixation strength and stability of the battery rack structure.

[0003] If the battery rack structure is not designed properly during ship navigation, the battery modules may be displaced, collide, or even detach from the battery rack due to the multi-directional forces generated by the ship's turbulence, acceleration, and turning. This can lead to safety hazards such as battery failure and short circuits, which seriously restricts the promotion and application of lithium battery-powered ships.

[0004] A search of existing technologies revealed that Chinese patent document CN119231072A (publication date December 31, 2024) discloses an energy storage battery rack beam assembly, a battery pack, and an energy storage device, and Chinese patent document CN114128017A (publication date March 1, 2022) discloses a battery rack with a fixed frame and an energy storage system. However, the above-mentioned existing technologies do not consider the complex operating conditions of ship navigation, lack the design of the correspondence between operating parameters and battery rack structural parameters, and cannot meet the reliability requirements of battery module fixation during ship navigation. Summary of the Invention

[0005] This invention proposes a design method and structure for fixing battery racks on ships. By establishing a mapping relationship between navigation conditions and structural forces, and combining mechanical modeling and constraint optimization, the precise design of the battery rack fixing structure is achieved, ensuring the stable fixing of battery modules under complex navigation conditions.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A method for designing a battery rack fixing structure for ships includes the following steps: Step S1) Using the longitudinal acceleration a in the ship coordinate system x lateral acceleration a y Vertical acceleration a z Define actual navigation conditions; Based on historical acceleration data, the empirical acceleration a1 in the longitudinal direction, the empirical acceleration a2 in the lateral direction, and the empirical acceleration a3 in the vertical direction of the battery module are determined. Step S2) Calculate the force parameters F1, F2, and F3 of the fixed structure in three directions according to F=ma; Step S3) Decompose the fixed structure into three independent cantilever beam models, corresponding to longitudinal, transverse, and vertical forces, respectively; Step S4) Calculate the maximum deflection δ of the three cantilever beam models under forces F1, F2, and F3; Step S5) Design constraint equations and optimize parameters based on the maximum deflection δ, specifically including: Set the safety factor η and the allowable offset p of the tip of the fixed structure, and establish the bending strength constraint equation f(η,δ)≤p; Set a reference dimension parameter set [b0,t0,l0] for the fixed structure, and establish the structural strength constraint equation g(b,t,l)≥[b0,t0,l0]; Set the height parameter h of the fixed structure and the reference height parameter H of the battery module, and establish the height constraint equation h≥H, where h is the height of the side of the battery rack fixed structure that the battery module can enter. Where l is the cantilever length, b is the cantilever width, and t is the cross-sectional thickness; Step S6) Solve the constraint equations and calculate the design parameters b, t, l, and h of the fixed structure.

[0007] Furthermore, the ship coordinate system in step S1 is defined as follows: The longitudinal positive direction points towards the bow; The transverse direction points to the starboard side; Vertically downwards in the positive direction.

[0008] Furthermore, the disassembly rules for the cantilever beam in step S2 are as follows: The connection between each layer of battery rack panels and the vertical panels of the fixed structure is considered a cantilever beam. The connection between the vertical and horizontal plates of a fixed structure is considered a cantilever beam.

[0009] Furthermore, the formula for calculating the maximum deflection δ in step S2 is as follows: Where E is the elastic modulus of the material and I is the moment of inertia of the cross section.

[0010] Furthermore, the flexural strength constraint equation in step S3 is η·δ≤p, Where η is the safety factor and p is the allowable offset of the tip.

[0011] Furthermore, in the structural strength constraint equation of step S3, the design parameters are b≥b0, t≥t0, and l≥l0.

[0012] The battery rack fixing structure for the ship used in the aforementioned design method includes two vertically erected plates, which are respectively attached to the four corners of the battery module. The lower ends of the plates along both sides are provided with baffles, which are vertically erected and extend longitudinally. The upper ends of the plates are provided with cover plates in the horizontal direction, which extend longitudinally. The distance between the upper end of the baffles and the lower end of the cover plates is greater than the height of the battery module.

[0013] Compared with the prior art, the present invention has the following advantages: By establishing a mapping relationship between the ship's navigation conditions and the forces on the battery rack, a structural design based on actual navigation conditions is achieved, thus solving the reliability problem of battery fixation under complex conditions. The fixed structure is decomposed into a cantilever beam model, and the maximum deflection is calculated using material mechanics formulas, providing a precise quantitative basis for structural strength design. Constraint equations are established from three dimensions: bending strength, structural strength, and ease of use, to ensure that the design parameters meet both mechanical performance requirements and actual installation and use needs.

[0014] This invention can quickly determine the structural parameters of the battery rack under different working conditions, which facilitates engineering applications and promotes the adoption of electric ships. Attached Figure Description

[0015] Figure 1 This is a flowchart of the battery rack fixing structure design method of the present invention; Figure 2 This is an isometric view of the battery rack fixing structure of the present invention; Figure 3 This is a partial enlarged view of the battery rack fixing structure plate of the present invention; Figure 4 This is a front view of the battery holder fixing structure of the present invention; Figure 5 This is a front view of the cantilever beam of the present invention; Figure 6 This is an isometric schematic diagram of the cantilever beam of the present invention; Figure Labels 1. Battery module, 2. Plate, 3. Baffle, 4. Cover plate. Detailed Implementation

[0016] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This embodiment proposes a battery rack fixing structure for ships, such as...Figure 2 and Figure 3 As shown, the device includes two vertically erected plates 2, which are attached to the four corners of the battery module 1. The lower ends of the plates 2 along both sides are provided with baffles 3, which are vertically erected and extend longitudinally. The upper end of the plates 2 is provided with a cover plate 4 in the horizontal direction, which extends longitudinally. The distance between the upper end of the baffles 3 and the lower end of the cover plate 4 is greater than the height of the battery module 1, which is used to accommodate the battery module 1 to be placed between the baffles 3 and the cover plate 4 into the battery rack fixing structure. After the battery module 1 is placed, the baffles 3 block and limit the battery module 1 in the horizontal direction, and the plates 2 block and limit the battery module 1 in the vertical direction.

[0018] This embodiment proposes a design method for a battery rack fixing structure for ships, such as... Figure 1 As shown, it includes the following steps: 1) Establish the working condition-force mapping relationship Define the ship's coordinate system: adopt an orthogonal coordinate system, with the positive longitudinal direction pointing towards the bow, the positive transverse direction pointing towards the starboard side, and the positive vertical direction pointing vertically downwards; Operating Parameter Acquisition: The longitudinal acceleration 'a' is extracted from historical data recorded by the ship's acceleration sensors during navigation. x lateral acceleration a y Vertical acceleration a z Determine the actual navigation conditions; based on the actual navigation conditions, obtain the empirical acceleration value a1 in the longitudinal direction, the empirical acceleration value a2 in the lateral direction, and the empirical acceleration value a3 in the vertical direction for battery module 1. Force parameter calculation: According to Newton's second law F=ma, calculate the force parameters F1, F2, and F3 of the battery rack fixing structure in three directions, where m is the mass of battery module 1.

[0019] Solve the above set of constraint equations to obtain the design parameters b, t, l, and h of the battery rack fixing structure that satisfy all constraints, and complete the structural design.

[0020] In this embodiment, the battery rack fixing structure consists of two vertically erected plates 2, which fit against the four corners of the battery module 1. The battery module 1 is stably fixed through multi-directional constraints, preventing displacement or detachment during navigation.

[0021] The simulated ship navigation conditions are as follows: Longitudinal acceleration a x =800mm / s 2 lateral acceleration a y =1500mm / s 2 Vertically with a z =20mm / s 2 The periodic acceleration is of amplitude. The battery rack is made of 45 steel with an elastic modulus E=206GPa; The specific parameters of battery module 1 are as follows: Dimensions: 565mm*322.5mm*150mm Height H = 150 mm, mass m = 28.2475 kg; Empirical acceleration values ​​are determined based on historical data. a1=1300mm / s 2 (Vertical) a2 = 2000 mm / s 2 (Horizontal) a3=20mm / s 2 (Vertical) Longitudinal force F1 = m * a1 = 28.2475 kg * 1300 mm / s 2 =36721.75mN=36.72175N; Lateral force F2 = m * a2 = 28.2475 kg * 2000 mm / s 2 =73443.5mN=73.4435N; Vertical force F3 = m * a3 = 28.2475 kg * 20 mm / s 2 =564.95mN=0.56495N, The battery holder fixing structure is used in pairs, so F3 multiplied by the coefficient 2 is 1.1299N.

[0022] 2) Mechanical modeling of cantilever beams Structural disassembly rules: The battery rack fixing structure is disassembled into three independent cantilever beam models, corresponding to longitudinal, transverse, and vertical forces, respectively; The disassembly principle is as follows: the connection between each layer of battery rack plate 2 and the vertical plate 2 of the fixed structure is regarded as a cantilever beam, and the connection between the vertical plate 2 and the horizontal plate 2 in the fixed structure is regarded as a cantilever beam.

[0023] Maximum deflection calculation: The formula for calculating the maximum deflection δ (maximum bending deformation) of a cantilever beam is as follows: Where l is the cantilever length, q is the uniformly distributed load, E is the material's elastic modulus, and I is the moment of inertia of the cross section. (See [reference needed]) Figure 5 ; For a cantilever beam with a rectangular cross-section, the formula for calculating the moment of inertia is: , Where b is the cantilever width and t is the cross-sectional thickness, see [reference] Figure 6 .

[0024] 3) Design constraint equations and optimize parameters Bending strength constraint: Set a safety factor η and an allowable offset p at the tip, and establish the constraint equation η・δ≤p to ensure that the bending deformation of the cantilever beam under stress does not exceed the allowable range.

[0025] Structural strength constraints: Set a reference dimension parameter set [b0,t0,l0], establish the constraint equation g(b,t,l)≥[b0,t0,l0], requiring that the design parameters b, t, and l are not less than the corresponding reference dimensions to ensure the load-bearing strength of the structure itself; Height Constraint: Set a reference height parameter H, where H is the height of battery module 1. Establish the constraint equation h ≥ H, where h is the height of the side of the battery rack fixing structure that allows battery module 1 to enter, ensuring that battery module 1 can be smoothly placed and vertically fixed. Figure 4 As shown.

[0026] The parameter design and constraints for each cantilever beam are as follows: Longitudinal cantilever beam: safety factor η1=2.5, allowable offset at the tip p1=10mm; according to the constraint equation η1・δ1≤p1, combined with the deflection formula, the structural parameters t1=3mm (section thickness), l1=173mm (cantilever length), b1=20mm (cantilever width) are calculated, which meet the requirements of bending strength and structural strength. Laterally stressed cantilever beam: safety factor η2=2.5, allowable offset at the tip p2=2mm; determined parameters: t2=3mm, l2=15mm, b2=40mm.

[0027] Vertically stressed cantilever beam: safety factor η3=2.5, allowable offset at the tip p3=5mm; determined parameters: t3=3mm, l3=40mm, b3=322.5mm; According to the height constraint equation h≥H, h=160mm is selected, which is greater than the height of battery module 1, H=150mm, to ensure that battery module 1 can be installed smoothly.

[0028] Simulations of acceleration, turning, and turbulence during ship navigation demonstrate that the battery rack fixing structure designed with the above parameters exhibits maximum deformation less than the allowable offset in all three directions, and battery module 1 shows no displacement or detachment, thus meeting the requirements for stable fixing.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for a battery rack fixing structure for ships, characterized in that, Includes the following steps: Step S1) Using the longitudinal acceleration a in the ship coordinate system x lateral acceleration a y Vertical acceleration a z Define actual navigation conditions; Based on historical acceleration data, the empirical acceleration a1 in the longitudinal direction, the empirical acceleration a2 in the lateral direction, and the empirical acceleration a3 in the vertical direction of the battery module are determined. Step S2) Calculate the force parameters F1, F2, and F3 of the fixed structure in three directions according to F=ma; Step S3) Decompose the fixed structure into three independent cantilever beam models, corresponding to longitudinal, transverse, and vertical forces, respectively; Step S4) Calculate the maximum deflection δ of the three cantilever beam models under forces F1, F2, and F3; Step S5) Design constraint equations and optimize parameters based on the maximum deflection δ, specifically including: Set the safety factor η and the allowable offset p of the tip of the fixed structure, and establish the bending strength constraint equation f(η,δ)≤p; Set a reference dimension parameter set [b0,t0,l0] for the fixed structure, and establish the structural strength constraint equation g(b,t,l)≥[b0,t0,l0]; Set the height parameter h of the fixed structure and the reference height parameter H of the battery module, and establish the height constraint equation h≥H, where h is the height of the side of the battery rack fixed structure that the battery module can enter. Where l is the cantilever length, b is the cantilever width, and t is the cross-sectional thickness; Step S6) Solve the constraint equations and calculate the design parameters b, t, l, and h of the fixed structure.

2. The design method for fixing a battery rack for ships according to claim 1, characterized in that, In step S1, the ship's coordinate system is defined as follows: The longitudinal positive direction points towards the bow; The transverse direction points to the starboard side; Vertically downwards in the positive direction.

3. The design method for fixing a battery rack for ships according to claim 1, characterized in that, The disassembly rules for the cantilever beam in step S2 are as follows: The connection between each layer of battery rack panels and the vertical panels of the fixed structure is considered a cantilever beam. The connection between the vertical and horizontal plates of a fixed structure is considered a cantilever beam.

4. The design method for fixing a battery rack for ships according to claim 1, characterized in that, The formula for calculating the maximum deflection δ in step S2 is as follows: Where E is the elastic modulus of the material and I is the moment of inertia of the cross section.

5. The design method for fixing a battery rack for ships according to claim 1, characterized in that, In step S3, the flexural strength constraint equation is η·δ≤p. Where η is the safety factor and p is the allowable offset of the tip.

6. The design method for fixing a battery rack for ships according to claim 1, characterized in that, In the structural strength constraint equation of step S3, the design parameters are b≥b0, t≥t0, and l≥l0.

7. A marine battery rack fixing structure for implementing the marine battery rack fixing structure design method according to any one of claims 1-6, characterized in that, It includes two vertically erected plates, which are respectively attached to the four corners of the battery module. The lower ends of the plates along both sides are provided with baffles, which are vertically erected and extend longitudinally. The upper ends of the plates are provided with cover plates in the horizontal direction, which extend longitudinally. The distance between the upper end of the baffles and the lower end of the cover plates is greater than the height of the battery module.

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