A lower housing of a battery pack and a battery pack

Abstract

This utility model relates to the field of battery pack technology, specifically to a lower housing of a battery pack and a battery pack. The lower housing includes a shell body, a reinforcing frame, and a lug assembly. The shell body includes a first cavity structure and a second cavity structure spaced apart along its length, forming a clearance area between them to accommodate a vehicle driveshaft. The reinforcing frame is disposed at the first cavity structure, the clearance area, and the second cavity structure to strengthen the structural strength of these three areas, and the reinforcing frame portion at the first cavity structure is connected to the reinforcing frame portion at the second cavity structure. Multiple lug assemblies are provided, arranged at least along both sides of the shell body, and connected to the reinforcing frame. The lower housing and battery pack provided by this utility model can avoid the vehicle driveshaft, and the lower housing has high structural strength and is not easily deformed, meeting the usage requirements.

Description

Technical Field

[0001] This utility model relates to the field of battery pack technology, specifically to a lower housing of a battery pack and a battery pack. Background Technology

[0002] In the field of new energy vehicles, especially in the technical solutions for converting gasoline vehicles into electric vehicles, the design of the lower casing of the battery pack needs to be adapted to the original vehicle chassis structure, often facing challenges in strength and stability due to non-standard layouts.

[0003] Traditional battery packs often use a U-shaped or irregularly shaped clearance structure in the middle to avoid the vehicle's drive shaft. This results in uneven stress on the entire casing, especially in the clearance area and at the connection between adjacent cavities, which can easily cause local deformation and affect the reliability of the structure. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a lower housing of a battery pack and a battery pack that can avoid the drive shaft of a vehicle, and the lower housing of the battery pack has high structural strength and is not easily deformed.

[0005] To achieve the above and other related objectives, this utility model provides a lower housing for a battery pack, comprising:

[0006] The shell body includes a first cavity structure and a second cavity structure that are spaced apart along the length direction, and the two form a clearance area to adapt to the vehicle drive shaft.

[0007] A reinforcing skeleton is provided at the first cavity structure, the avoidance area, and the second cavity structure to enhance the structural strength of these three areas, and the reinforcing skeleton portion at the first cavity structure is connected to the reinforcing skeleton portion at the second cavity structure.

[0008] Multiple lifting lug assemblies are provided, arranged at least along both sides of the shell body, and connected to the reinforcing frame.

[0009] In one embodiment of the present invention, the shell body is disposed between the lifting lug assembly and the reinforcing frame, and the overlapping portions of the lifting lug assembly, the reinforcing frame and the shell body are connected.

[0010] In one embodiment of this utility model, the extensibility of the shell body is greater than that of the lifting lug assembly and the reinforcing frame;

[0011] The shell body and the lug assembly, as well as the shell body and the reinforcing frame, are pre-fixed and connected through the first welding point of the two overlapping areas;

[0012] The overlapping portions of the lug assembly, the shell body, and the reinforcing frame are reinforced and fixedly connected by the second welding point in the three-layer overlapping area.

[0013] In one embodiment of the present invention, the lifting lug assembly includes a plurality of lifting lug components, each of which overlaps with the shell body and the reinforcing frame on the bottom and side surfaces of the shell body.

[0014] In one embodiment of this utility model, the reinforcing frame includes:

[0015] The cavity skeleton unit includes two units, which are respectively disposed in the first cavity structure and the second cavity structure;

[0016] An arc-shaped reinforcing unit is disposed in the avoidance area, and the arc-shaped reinforcing unit extends to the first cavity structure and the second cavity structure at both ends along the length direction of the shell body, and is connected to the two cavity skeleton units.

[0017] In one embodiment of this utility model, the cross-section of the avoidance area is an inverted U-shaped structure, and the cross-section of the arc-shaped reinforcing unit is a Z-shaped structure;

[0018] Along the width direction of the shell body, at least a portion of the cross-section of the arc-shaped reinforcing unit is fitted to the surface contour of the avoidance area.

[0019] In one embodiment of the present invention, at least a portion of the cross-section of the arc-shaped reinforcing unit is spaced apart from the cross-section of the avoidance area along the width direction of the shell body, so that a pressure-resistant cavity is formed between the arc-shaped reinforcing unit and the shell body.

[0020] In one embodiment of this utility model, the cavity skeleton unit includes:

[0021] A transverse reinforcing unit extends along the width direction of the shell body and is fixedly connected to the bottom of the first cavity structure and the second cavity structure;

[0022] The longitudinal reinforcing unit extends along the length of the shell body and intersects with the transverse reinforcing unit and / or the arc-shaped reinforcing unit to form a reinforcing grid structure.

[0023] In one embodiment of this utility model, the longitudinal reinforcing units are all disposed on both sides of the transverse reinforcing unit;

[0024] The transverse reinforcing unit is provided with a first reinforcing rib;

[0025] The longitudinal reinforcing unit is provided with a second reinforcing rib;

[0026] And / or the bottom of the shell body is provided with a plurality of inwardly protruding reinforcing bosses.

[0027] To achieve the above-mentioned objectives and other related objectives, this utility model provides a battery pack, including the lower housing of the battery pack.

[0028] In summary, this utility model, through the integrated design of a three-region reinforced skeleton, connects the skeleton portion of the first cavity structure, the avoidance area, and the second cavity structure into an overall load-bearing frame. This disperses bottom stress laterally, suppresses sidewall deformation longitudinally, and the arc-shaped structure conforms to the contour of the avoidance area to resist local pressure and deformation. The fixed connection between the lifting lug assembly and the reinforced skeleton utilizes the high strength characteristics of the reinforced skeleton to avoid direct stress on the low-strength area of ​​the shell body, thereby improving connection reliability. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the overall structure of the lower housing of the battery pack in one embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of one side structure of the lower housing of the battery pack in one embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the reinforced skeleton structure in one embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of one of the longitudinal reinforcing units in one embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of another longitudinal reinforcing unit in one embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the lifting lug assembly structure on one side of the shell body in one embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the arc-shaped reinforcing unit in one embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the shell body structure in one embodiment of the present utility model;

[0038] Figure 9 This is a top view of the lower housing of the battery pack in one embodiment of the present invention;

[0039] Figure 10 for Figure 9The structural cross-sectional view at point AA;

[0040] Figure 11 for Figure 10 Enlarged view of the structure at point C;

[0041] Figure 12 for Figure 9 The structural cross-sectional view at point BB;

[0042] Figure 13 This is a schematic diagram of a structure in which a fluid cooling unit is installed inside the lower housing of a battery pack according to one embodiment of the present invention;

[0043] Component labeling description: Shell body 1, First cavity structure 11, Second cavity structure 12, Avoidance area 13, Reinforcing boss 101, First welding point 102, Second welding point 103, Shell bottom plate 104, Reinforcing frame 2, Cavity frame unit 21, Lateral reinforcing unit 211, Longitudinal reinforcing unit 212, Arc-shaped reinforcing unit 22, Pressure-resistant cavity 221, Lifting lug assembly 3, Lifting lug component 31, Fluid cooling unit 4. Detailed Implementation

[0044] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terminology used in the embodiments of this utility model is for describing specific implementation schemes and not for limiting the scope of protection of this utility model. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0045] Please see Figures 1 to 13It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0046] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention.

[0047] Please see Figure 1-3 This utility model provides a lower housing for a battery pack, including a housing body 1, a reinforcing frame 2, and a lifting lug assembly 3;

[0048] The shell body 1 includes at least a first cavity structure 11 and a second cavity structure 12 spaced apart along the length direction, and an avoidance area 13 adapted to the vehicle drive shaft is provided or formed between the first cavity structure 11 and the second cavity structure 12.

[0049] The reinforcing skeleton 2 is disposed at the first cavity structure 11, the avoidance area 13 and the second cavity structure 12 to strengthen the structural strength of the three areas, and the reinforcing skeleton 2 part at the first cavity structure 11 is connected to the reinforcing skeleton 2 part at the second cavity structure 12.

[0050] Multiple lifting lug assemblies 3 are provided, arranged at least along both sides of the shell body 1, and connected to the reinforcing frame 2, wherein, for example... Figure 1 As shown, the length direction is X and the width direction is Y.

[0051] It should be noted that the shell body 1 is generally the inner liner of the lower shell of the battery pack, and is generally made of a material with good ductility. The shell body 1 is formed by two cavity structures (first cavity structure 11 and second cavity structure 12) separated along the length direction. The first cavity structure 11 and the second cavity structure 12 can be integrally formed, or they can be welded together from independent first cavity structures 11 and second cavity structures 12. If they are welded, the welding position is generally located in the clearance area 13. It should be understood that a third cavity structure, a fourth cavity structure, or more cavity structures may also be included on one side of the clearance area 13, and more clearance areas 13 may be provided. The clearance area 13 between the first cavity structure 11 and the second cavity structure 12 is designed according to the layout requirements of the vehicle drive shaft, adapting to its shape and space requirements. The clearance area 13 can be a U-shaped, V-shaped, stepped, or combined groove structure, covering all drive shaft adaptation forms. The cavity structure can be rectangular, trapezoidal, or irregular cross-section to accommodate battery modules or liquid cooling components. The sidewalls of the clearance area 13 can be equipped with guide channels or reinforcing ribs to disperse stress or assist in heat dissipation. The reinforcing frame 2 is distributed in three key areas of the shell body 1 (two cavities and clearance area 13). The frame parts connecting the two cavities form an overall load-bearing frame, improving the resistance to compression and deformation. The reinforcing frame 2 can be an integral frame (such as an integrated mesh structure), a split module (such as a combination of detachable crossbeams and longitudinal beams), or a multi-part welded structure (such as crossbeam + longitudinal beam + arc beam welding). The connection methods include welding, riveting, and bolt connection, covering all mechanical connection forms. The frame material can be aluminum alloy, high-strength steel, or composite materials (such as carbon fiber reinforced plastic) to adapt to different lightweight and strength requirements. The lifting lug assemblies 3 are distributed on both sides of the shell body 1, such as both sides in the length direction or both sides in the width direction of the shell body 1. The lifting lug assemblies 3 are fixedly connected to the reinforcing frame 2 to achieve stable installation of the battery pack and the vehicle frame. The lifting lugs can be independent lifting lugs, integrated connecting blocks or combined snap-fit ​​structures; the connection methods include through welding, bolt pre-tightening or clamping fixation, covering all tensile connection schemes; the lifting lug assemblies 3 can extend to the front and rear ends of the shell body 1 to form a ring distribution, improving the multi-directional load bearing capacity.

[0052] In traditional battery pack conversion scenarios, the lower casing suffers from insufficient structural strength due to non-standard avoidance design, making stress concentration deformation prone to occur at the connection between the avoidance area 13 and the cavity. In this case, the three-area integrated design of the reinforced frame 2 connects the first cavity structure 11, the avoidance area 13, and the skeleton of the second cavity structure 12 into an integral load-bearing frame. This disperses bottom stress laterally, suppresses sidewall deformation longitudinally, and the arc-shaped structure conforms to the contour of the avoidance area 13 to resist local pressure. The fixed connection between the lifting lug assembly 3 and the reinforced frame 2 utilizes the high strength characteristics of the reinforced frame 2 to avoid direct stress on the low-strength area of ​​the casing body 1, thereby improving connection reliability.

[0053] Please see Figure 1-3 as well as Figure 9-11 As one of the optional embodiments of this case, the shell body 1 is disposed between the lug assembly 3 and the reinforcing frame 2, and the overlapping parts of the lug assembly 3, the reinforcing frame 2 and the shell body 1 are connected.

[0054] It should be noted that the shell body 1, as an intermediate layer structure, is located in the interlayer between the lifting lug assembly 3 and the reinforcing frame 2, forming a stacked layout of "lifting lug assembly 3 - shell body 1 - reinforcing frame 2"; buffer materials (such as rubber pads or honeycomb aluminum) can be filled between the shell body 1, the lifting lug assembly 3, and the reinforcing frame 2 to absorb vibration; in the overlapping area of ​​the lifting lug assembly 3, the shell body 1, and the reinforcing frame 2, the three are fixed by physical connection to form an integrated force-bearing node, including through welding, bolt pre-tightening, or riveting, covering all mechanical or chemical connection methods; through holes, grooves, or bosses can be opened in the overlapping part to enhance the connection strength and positioning accuracy.

[0055] In traditional battery packs, the lifting lug assembly 3 is directly welded to the shell body 1 in the lower casing, leading to stress concentration in the connection area. This makes it prone to tearing failure due to differences in material strength, affecting the installation stability and lifespan of the battery pack. This invention places the shell body 1 between the lifting lug assembly 3 and the reinforcing frame 2, and utilizes the connection design of the overlapping areas to form a sandwich-type load-bearing structure: the shell body 1 acts as the intermediate layer, dispersing the tensile and shear forces borne by the lifting lug assembly 3 to the reinforcing frame 2, avoiding localized stress concentration; the high-strength characteristics of the reinforcing frame 2 bear the main load, while the shell body 1 provides auxiliary support and stiffness compensation; the high-strength materials of the outer layer (lifting lug assembly 3) and inner layer (reinforcing frame 2) wrap around the intermediate layer (shell body 1), protecting the low-strength shell body 1 from direct impact; the fixed connection in the overlapping areas forms multiple force transmission paths, improving the tensile, shear, and fatigue resistance of the nodes.

[0056] Please see Figure 1-3 as well as Figure 9-11 As one of the optional embodiments in this case, the shell body 1 has greater extensibility than the lug assembly 3 and the reinforcing frame 2;

[0057] The shell body 1 and the lug assembly 3, as well as the shell body 1 and the reinforcing frame 2, are pre-fixed and connected through the first welding point 102 of the two overlapping areas.

[0058] The overlapping portions of the lifting lug assembly 3, the shell body 1, and the reinforcing frame 2 are reinforced and fixedly connected by the second welding point 103 in the three-layer overlapping area, so that the lifting lug assembly 3 and the reinforcing frame 2 can directly transmit force through the second welding point 103.

[0059] It should be noted that the shell body 1 is made of a highly ductile material (such as aluminum alloy, low-strength steel, or pure aluminum and magnesium alloy), while the lifting lug assembly 3 and the reinforcing frame 2 are made of high-strength, low-ductility materials (such as hardened steel, titanium alloy high-carbon steel, or martensitic stainless steel). This difference in material properties achieves mechanical synergy. At the contact surfaces between the shell body 1 and the lifting lug assembly 3, and between the shell body 1 and the reinforcing frame 2, initial fixing is achieved through two layers of spot welding, butt welding, or fusion welding to form the basic connection interface. Generally, fusion welding of the shell body 1 is minimized to avoid deformation during welding and affecting accuracy. Before pre-fixing, the contact surfaces can be sandblasted, plated, or coated with flux to enhance the welding bond. In the overlapping areas of the lifting lug assembly 3, the shell body 1, and the reinforcing frame 2, a three-layer continuous welding process (such as butt welding or deep penetration welding) is used for reinforcement, forming a high-strength connection node.

[0060] In traditional solutions, when the lifting lug assembly 3 is directly welded to the shell body 1, the difference in material strength (high-strength lifting lug and low-strength shell) easily leads to tearing of the weld interface, and a single weld layer is insufficient to disperse stress concentration under dynamic loads. This invention solves this problem through a combination of material property gradient design and layered welding process. The ductile shell body 1 acts as a buffer layer, absorbing thermal stress and mechanical impact in the welding area, avoiding brittle fracture caused by direct action of high-strength materials; two layers of pre-fixed welding provide initial positioning and stress transfer paths, reducing the risk of subsequent welding deformation; three layers of reinforcing welding form a composite weld bead in the overlapping area, enhancing the tensile, shear, and fatigue resistance of the connection node through multi-level penetration and filler metal, while utilizing the ductility of the shell body 1 to offset residual welding stress.

[0061] Please see Figure 1 and Figure 6 As one of the optional embodiments of this case, the lifting lug assembly 3 includes a plurality of lifting lug sub-components 31, and each of the lifting lug sub-components 31 overlaps with the shell body 1 and the reinforcing frame 2 on the bottom and side surfaces of the shell body 1.

[0062] It should be noted that the lifting lug 31, as a connecting unit, must overlap with the bottom and side areas of the shell body 1, and form a fixed connection with the reinforcing frame 2 to ensure that the force path passes through the key areas of the shell body 1 and the reinforcing frame 2. The lifting lug 31 can be L-shaped, U-shaped, or flat connecting block to adapt to different installation requirements. In the overlapping areas, the bottom overlapping part can be provided with a boss or groove to enhance positioning accuracy, and the side overlapping part can be provided with a guide hole or reinforcing rib to disperse stress. In addition to welding, the connection method can be bolt pre-tightening or riveting, covering all mechanical and chemical connection forms.

[0063] Traditional lifting lug assembly 3 is only connected to the shell body 1 or a single frame structure, resulting in a single force path and susceptibility to local fatigue fracture. This solution uses the lifting lug sub-assembly 31 to connect with the shell body 1 and the frame on both the bottom and side surfaces, forming a multi-directional force transmission path. The shell body 1 absorbs vibration energy through its ductility, while the frame 2 bears the main load due to its high strength, thus avoiding stress concentration. This significantly improves the tensile strength and fatigue resistance of the lifting lug assembly 3, ensuring the installation stability of the battery pack under dynamic loads. At the same time, the multi-area overlapping design enhances the redundancy of the connection nodes, reducing the risk of failure.

[0064] Please see Figure 3 As one of the optional embodiments of this case, the reinforcing skeleton 2 includes a cavity skeleton unit 21 and an arc-shaped reinforcing unit 22; the cavity skeleton unit 21 includes two units, which are respectively disposed in the first cavity structure 11 and the second cavity structure 12; the arc-shaped reinforcing unit 22 is disposed in the avoidance area 13, and the arc-shaped reinforcing unit 22 extends to the first cavity structure 11 and the second cavity structure 12 at both ends along the length direction of the shell body 1, and is connected to the two cavity skeleton units 21.

[0065] It should be noted that the reinforcing frame 2 consists of cavity frame units 21 and arc-shaped reinforcing units 22. The cavity frame units 21 are embedded inside or outside the two cavity structures respectively, and the arc-shaped reinforcing units 22 span the avoidance area 13 and connect with the cavity frame units 21 on both sides to form a continuous support frame. The cavity frame unit 21 can be a grid frame, corrugated plate or honeycomb sandwich panel, adapting to different cavity shapes and strength requirements; the arc-shaped reinforcing unit 22 can be in the form of a Z-shaped beam, segmented arc plate or continuous curved surface structure, covering all contours adapted to the avoidance area 13; the arc-shaped reinforcing unit 22 and the cavity frame unit 21 can be connected by welding, bolt fastening or integral molding process, supporting modular assembly and quick replacement.

[0066] Traditional reinforced frame 2 lacks continuity between the avoidance area 13 and the cavity structure, resulting in an interruption of the stress transfer path. This solution, through the extension design of the two ends of the arc-shaped reinforcing unit 22, transfers the local load of the avoidance area 13 to the cavity frame units 21 on both sides, forming an overall force network. This suppresses cavity deformation laterally and improves bending stiffness longitudinally. Therefore, the continuous connection between the arc-shaped unit and the cavity frame unit 21 significantly enhances the compressive strength and structural stability of the avoidance area 13, preventing deformation of the shell body 1 due to localized stress concentration. Simultaneously, the modular design improves production efficiency and maintenance convenience.

[0067] Please see Figure 1-3 and Figure 7As one of the optional implementation methods in this case, the cross-section of the avoidance area 13 is an inverted U-shaped structure, and the cross-section of the arc-shaped reinforcing unit 22 is a Z-shaped structure.

[0068] Along the width direction of the shell body 1, at least a portion of the cross-section of the arc-shaped reinforcing unit 22 is fitted to fit the surface contour of the avoidance area 13.

[0069] It should be noted that the inverted U-shaped cross-section design of the avoidance area 13 is mainly used to adapt to the layout requirements of the vehicle driveshaft. Its opening faces downward to provide sufficient avoidance space, while the Z-shaped cross-section of the arc-shaped reinforcing unit 22 enhances local compressive strength. The Z-shaped arc-shaped reinforcing unit 22 has a top arc surface and two side extensions. Its arc surface fits the U-shaped inner wall contour of the avoidance area 13 to form a continuous support interface. In addition, the cross-section of the avoidance area 13 can be replaced with a V-shaped, grooved, or stepped structure to adapt to different driveshaft shapes; the cross-section of the arc-shaped reinforcing unit 22 can be replaced with a C-shaped or box-shaped structure to optimize compressive performance through different geometric shapes and bending stiffness. The fitting method includes full fitting (fitting along the entire width direction) or segmented fitting (selective fitting in critical or non-critical stress areas), and guide channels or buffer layers can be added to optimize stress distribution.

[0070] Traditional clearance zone 13, lacking internal support due to its single U-shaped structure, is prone to local collapse or deformation under dynamic loads. This design addresses this by using an arc-shaped reinforcing unit 22 with a Z-shaped cross-section that fits the contour of clearance zone 13, forming a double-walled composite structure. The top arc surface of the arc-shaped unit directly bears the load of clearance zone 13, while the extended sections on both sides transfer the force to the sidewalls of the shell body 1. This disperses stress and suppresses lateral deformation of the U-shaped area, thereby enhancing local structural stability and absorbing vibration energy through the interaction of the double-walled structure, reducing the risk of crack initiation. Furthermore, this design is compatible with variations in cross-sectional shapes, adapting to diverse chassis layout requirements, and achieving high reliability while ensuring lightweight construction.

[0071] Please see Figure 1-3 as well as Figure 10 and Figure 12 As one of the optional embodiments of this case, at least a portion of the cross-section of the arc-shaped reinforcing unit 22 is spaced apart from the cross-section of the avoidance area 13 along the width direction of the shell body 1, so that a pressure-resistant cavity 221 is formed between the arc-shaped reinforcing unit 22 and the shell body 1.

[0072] It should be noted that a pressure-resistant cavity 221 is formed between the arc-shaped reinforcing unit 22 and the avoidance area 13 through a spacing arrangement. This cavity absorbs energy through deformation when subjected to force, and the cavity can be filled with lightweight materials to enhance its pressure resistance. The spacing distance can be adjusted according to load requirements. For example, a smaller spacing can be used in the high-stress area of ​​the avoidance area 13 to enhance support, while a larger spacing can be used in the low-stress area to reduce weight. In alternative embodiments, the pressure-resistant cavity 221 can be a continuous cavity, a honeycomb-shaped segmented cavity, or a corrugated sandwich structure; the spacing arrangement can include uniform spacing, gradient spacing, or locally staggered spacing to adapt to different pressure resistance and weight reduction requirements. In addition, reinforcing ribs, damping materials, or flow channels can be added inside the cavity to further optimize mechanical properties or assist in heat dissipation.

[0073] While the direct contact between the avoidance area 13 and the arc-shaped reinforcing unit 22 in traditional designs can improve stiffness, it lacks an energy absorption mechanism and is prone to brittle failure under extreme loads. This solution utilizes a pressure-resistant cavity 221 formed by intervals to disperse impact energy through the elastic deformation capacity of the cavity structure. When external forces act on the avoidance area 13, the cavity buffers the peak load through compressive deformation, while the arc-shaped reinforcing unit 22 acts as a rigid support to limit excessive deformation. The cavity's presence allows for multifunctional integration through internal space design (such as compartmentalization or filling), enabling functions like heat insulation, noise reduction, or heat dissipation. For example, high-damping filling materials can be used in areas of frequent vibration, or heat dissipation channels can be incorporated in high-temperature areas. The design of the pressure-resistant cavity 221 significantly improves the battery pack's durability under complex loads and provides a structural foundation for subsequent functional upgrades (such as thermal management integration).

[0074] Please see Figure 3-5 As one of the optional embodiments of this case, the cavity skeleton unit 21 includes a transverse reinforcing unit 211 and a longitudinal reinforcing unit 212; the transverse reinforcing unit 211 extends along the width direction of the shell body 1 and is fixedly connected to the bottom of the first cavity structure 11 and the second cavity structure 12; the longitudinal reinforcing unit 212 extends along the length direction of the shell body 1 and is cross-connected with the transverse reinforcing unit 211 and / or the arc-shaped reinforcing unit 22 to form a reinforcing mesh structure.

[0075] It should be noted that the transverse reinforcing unit 211, as the main bottom support, functions to enhance the bending stiffness of the cavity bottom. It can be constructed using beams, corrugated plates, or honeycomb sandwich panels, and the material can be aluminum alloy, high-strength steel, or composite materials. The longitudinal reinforcing unit 212 forms a grid structure by intersecting with the transverse units. The intersection can be perpendicular, oblique, or radially distributed, and the intersection nodes can be fixed by welding, riveting, or integral molding. In alternative embodiments, the reinforcing grid structure can be replaced with a truss structure, a honeycomb frame, or a segmented spliced ​​grid to adapt to different cavity shapes and load requirements.

[0076] Traditional cavity skeletons lack systematic interaction between transverse and longitudinal units, resulting in dispersed stress transmission paths and insufficient local stiffness. This design addresses this by creating a mesh structure through the cross-connection of transverse and longitudinal units, evenly distributing the load across the entire skeleton network. Transverse reinforcing units 211 bear the bending stress in the width direction, while longitudinal reinforcing units 212 suppress deformation in the length direction. The cross nodes act as multi-directional force transmission hubs, preventing localized stress concentration. The coordinated connection with the arc-shaped reinforcing units 22 further transfers the load from the avoidance area 13 to the mesh structure, forming a closed-loop frame for overall stress distribution and achieving a balance between lightweight and high strength.

[0077] Please see Figure 3-5 As one of the optional embodiments in this case, the longitudinal reinforcing units 212 are all disposed on both sides of the transverse reinforcing unit 211;

[0078] The transverse reinforcing unit 211 is provided with a first reinforcing structure, and the longitudinal reinforcing unit 212 is provided with a second reinforcing structure; the first reinforcing structure and the second reinforcing structure extend at least along the length and / or width and / or height direction of the shell body 1;

[0079] And / or the bottom of the shell body 1 is provided with a plurality of inwardly protruding reinforcing bosses 101.

[0080] It should be noted that the extension directions of the first and second reinforcing structures can be selected in a single direction (e.g., only along the length) or a combination of multiple directions (e.g., length + width) according to the stress requirements. The first and second reinforcing structures are, for example, reinforcing ribs, and the cross-sectional shapes of the reinforcing ribs include T-shaped, L-shaped, or wavy shapes, or upward / downward protruding structures. The reinforcing bosses 101 at the bottom of the shell body 1 can be cylindrical, prismatic, or grid-arrayed protrusions or strips, and the height and distribution density of the bosses can be adjusted according to the stiffness requirements. In alternative embodiments, the reinforcing ribs can be replaced by grooves, ribs, or locally thickened structures, and the reinforcing bosses 101 can integrate heat dissipation holes or conductive channels to expand functionality. The longitudinal reinforcing units 212 are distributed on both sides of the transverse units, forming a symmetrical support frame to suppress the lateral torsion of the shell body 1. The first and second reinforcing structures extend in multiple directions, and the bending and torsional stiffness of the units is improved through cross-sectional geometric changes. For example, T-shaped cross-section reinforcing ribs provide additional bending resistance in the height direction. The reinforcing boss 101 at the bottom of the shell body 1 increases the bottom rigidity and disperses the concentrated stress at the module mounting point through local thickening or protrusion design, which significantly improves the stability of the lower shell under dynamic load.

[0081] Please see Figure 3 As one of the optional embodiments of this case, four longitudinal reinforcing units 212 are provided, two of which are provided in the first cavity structure 11 and the other two are provided in the second cavity structure 12.

[0082] It should be noted that the four longitudinal reinforcing units 212 are distributed to balance the longitudinal load transfer capacity of the two cavity structures and avoid stress concentration on one side. In alternative embodiments, the number of longitudinal reinforcing units 212 can be two, six or more, depending on the cavity length and load requirements.

[0083] Please see Figure 3 As one optional implementation in this case, the lateral reinforcing units 211 include multiple units. Lateral reinforcing units 211 are provided on both sides and the middle region of the first cavity structure 11 and on both sides and the middle region of the second cavity structure 12 along the length direction of the shell body 1. This design significantly improves the overall stability of the cavity structure through the symmetrically distributed longitudinal reinforcing units 212; the layout of the four units optimizes load distribution and reduces local stress concentration, making it particularly suitable for the bending resistance requirements of long-span cavities.

[0084] It should be noted that the transverse reinforcing units 211, arranged on both sides and in the central region of the cavity, form a multi-level support network. The number of these units can be adjusted to three, five, or more groups depending on the cavity length and stiffness requirements. In alternative embodiments, the transverse units can be designed as continuous beams, segmented ribs, or staggered grid structures, and the materials can be aluminum alloy, carbon fiber composite materials, or high-strength steel. For example, in high-vibration areas, the transverse reinforcing units 211 can employ a corrugated cross-section to enhance vibration resistance.

[0085] Please see Figure 3 As one of the optional embodiments of this case, the transverse reinforcing unit 211 and the longitudinal reinforcing unit 212 are arranged around the first cavity structure 11 and the second cavity structure 12 in a circumferential manner to form a closed-loop frame.

[0086] It should be noted that the transverse and longitudinal reinforcing units 212 form a closed-loop frame around the cavity circumferentially. Their arrangement can be a continuous ring or segmented splicing. Traditional cavity frames lack a circumferential closed-loop design, leading to interruptions in load transfer paths and making localized weak areas prone to cracking. This solution, through the closed-loop connection of the transverse and longitudinal units around the cavity, forms a continuous stress ring, laterally constraining cavity expansion and longitudinally suppressing bending deformation. The multi-directional stiffness enhancement capability of the closed-loop structure is particularly suitable for battery pack casings subjected to complex multi-axial loads.

[0087] Please see Figure 3 As one of the optional embodiments of this case, two arc-shaped reinforcing units 22 are provided at intervals along the width direction of the shell body 1, and are respectively located at both ends of the avoidance area 13.

[0088] It should be noted that the two arc-shaped reinforcing units 22 are placed at both ends of the avoidance area 13, forming a double support point to resist the lateral shear force. In an alternative embodiment, the number of arc-shaped reinforcing units 22 can be adjusted to three or more, and they are distributed equidistantly or in a gradient along the length of the avoidance area 13; the symmetrical layout of the double arc-shaped units optimizes the lateral load transfer path and reduces local stress peaks.

[0089] As one optional implementation of this invention, the transverse reinforcing unit 211, the longitudinal reinforcing unit 212, and the arc-shaped reinforcing unit 22 are all disposed in contact with the shell body 1. It should be noted that the direct contact design between each reinforcing unit and the shell body 1 ensures the continuity of the force transmission path, and the contact forms include surface contact, line contact, or point contact.

[0090] Please see Figure 9-11 As one of the optional embodiments of this case, a bottom plate 104 is provided at the bottom of the shell body 1 to strengthen the bottom structural strength of the shell body 1.

[0091] Please see Figure 13 To achieve the above-mentioned objectives and other related objectives, this utility model provides a battery pack, including the lower housing of the battery pack.

[0092] As one of the optional embodiments of this case, the battery pack further includes a cell module and a fluid cooling unit 4;

[0093] The cell module is disposed inside the lower housing of the battery pack;

[0094] The fluid cooling unit 4 is disposed between the lower housing and the cell module, and an elastic heat insulation layer is provided between the fluid cooling unit 4 and the lower housing of the battery pack.

[0095] It should be noted that the battery cell module can be a combination of square, pouch, or cylindrical batteries, and its arrangement can include stacked, array-type modular, or hybrid layouts to adapt to different energy densities and space requirements. The fluid cooling unit 4 includes a liquid cooling plate, microchannel cooling pipes, or a phase change material cooling system. Its fluid medium can be water, ethylene glycol solution, or insulating oil. The cooling path is designed as a serpentine, parallel, or branched network to optimize heat dissipation efficiency. The elastic thermal insulation layer is composed of silicone, ceramic fiber composite materials, or aerogel, or a sponge with a certain strength. Its form includes sheet-like, corrugated, or segmented splicing, which not only blocks the influence of external heat sources on the battery cell but also absorbs vibration energy during battery charging and discharging. In alternative embodiments, the fluid cooling unit 4 can integrate a temperature sensor or flow control valve to achieve intelligent temperature control, and the elastic thermal insulation layer can be composited with a conductive coating to balance the potential distribution.

[0096] Existing battery packs often face performance degradation issues due to structural deformation, uneven heat dissipation, and thermal shock under complex operating conditions. This solution significantly improves the overall reliability of the battery pack by integrating a reinforced lower casing, effective fluid cooling, and an elastic thermal insulation layer. The vibration-resistant design of the lower casing reduces mechanical stress on the cell modules and extends cycle life; the effective heat dissipation capacity of the fluid cooling unit 4 ensures that the cells operate within their optimal temperature range, improving energy output efficiency and safety; the dual function (thermal insulation and vibration reduction) of the elastic thermal insulation layer further optimizes thermal environment stability. In addition, the modular design supports rapid replacement of the cooling unit and thermal insulation layer, reducing maintenance costs and adapting to the upgrade needs of high-energy-density battery systems.

[0097] In this case, to meet the requirements of converting a gasoline vehicle into an electric vehicle, the existing chassis structure was reused. The external outline of the lower casing of the battery pack is unconventional, with a U-shaped structure in the middle to avoid the vehicle's drive shaft. This results in the lower casing being prone to deformation under stress. The shell body 1 of this battery pack includes a first cavity structure and a second cavity structure, with an overlapping surface between them. The two layers are first welded together, and then a ring of welded material is polished. Several rectangular inward-facing reinforcing bosses are machined from the bottom surface of the shell body 1 using sheet metal forming. These bosses serve two purposes: first, to strengthen the bottom surface and reduce deformation; and second, to increase the height to support internal structural components. Then, the arc-shaped reinforcing unit 22 is welded to the shell body 1. Since the arc-shaped reinforcing unit 22 itself has an arc surface structure, after welding, it forms a local cavity structure with the shell body 1, increasing the strength of the middle U-shaped position. When the front and rear ends (the length direction of the shell body 1) are subjected to large external forces, it can resist the pressure, thereby reducing the force transmitted to the shell body 1 itself, and thus reducing the degree of deformation of the middle overlapping surface. The seven transverse reinforcing units 211 are welded together with the ten lugs 31 in sequence, forming three-layer plate welds of lugs 31-shell body 1-transverse reinforcing unit 211 and lugs 31-shell body 1-arc-shaped reinforcing unit 22 in local positions. Because the shell body 1 is relatively high, the material selected has high ductility, so its tensile strength and yield strength are low. The lifting lug 31, the transverse reinforcing unit 211, and the longitudinal reinforcing unit 212 are all made of high-strength steel. If only high-strength steel and low-strength steel are welded together, the low-strength steel is easily torn when subjected to external force, causing welding failure and thus weakening the overall strength. Compared with two-layer plate welding, the three-layer plate welding method sandwiches the low-strength steel in the middle, so that when subjected to external force, the outer plate bears the force first, and then the middle plate bears the force, thus making it relatively more stable.

[0098] Four longitudinal reinforcing units 212 are welded together with the shell body 1, the transverse reinforcing unit 211, and the lifting lug assembly 3 to form several three-layer plate structures, which are then welded together. By employing a large number of three-layer plate splicing and welding methods, the lower shell of this battery pack wraps the shell body 1 between the lifting lug assembly 3 and the reinforcing frame 2, thereby achieving the purpose of improving the overall strength.

[0099] Install the liquid cooling component 3 in the lower housing of the battery pack. Lift the three modules into the installation position of the lower housing of the battery pack using a hook. Secure the modules to the lower housing of the battery pack with bolts. Then connect the water pipes to make the water pipes of the three modules connected. Fix the BMS component to the top of the front module with bolts. Connect all the wiring harnesses and conductive parts. At this point, the entire battery pack installation is complete.

[0100] In summary, this utility model effectively overcomes some practical problems in the prior art, thus having high utilization value and significance.

[0101] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A lower casing for a battery pack, characterized in that, include: The shell body includes a first cavity structure and a second cavity structure that are spaced apart along the length direction, and the two form a clearance area to adapt to the vehicle drive shaft. A reinforcing skeleton is provided at the first cavity structure, the avoidance area, and the second cavity structure to enhance the structural strength of these three areas, and the reinforcing skeleton portion at the first cavity structure is connected to the reinforcing skeleton portion at the second cavity structure. The lifting lug assembly is arranged at least along both sides of the shell body and connected to the reinforcing frame.

2. The lower housing of the battery pack according to claim 1, characterized in that, The shell body is disposed between the lug assembly and the reinforcing frame, and the overlapping portions of the lug assembly, the reinforcing frame and the shell body are connected.

3. The lower housing of the battery pack according to claim 1, characterized in that, The shell body has greater ductility than the lug assembly and the reinforcing frame; The shell body and the lug assembly, as well as the shell body and the reinforcing frame, are pre-fixed and connected through the first welding point of the two overlapping areas; The overlapping portions of the lug assembly, the shell body, and the reinforcing frame are reinforced and fixedly connected by the second welding point in the three-layer overlapping area.

4. The lower housing of the battery pack according to claim 3, characterized in that, The lifting lug assembly includes multiple lifting lug components, each of which overlaps with the shell body and the reinforcing frame on the bottom and side surfaces of the shell body.

5. The lower housing of the battery pack according to claim 1, characterized in that, The reinforcing frame includes: The cavity skeleton unit includes two units, which are respectively disposed in the first cavity structure and the second cavity structure; An arc-shaped reinforcing unit is disposed in the avoidance area, and the arc-shaped reinforcing unit extends to the first cavity structure and the second cavity structure at both ends along the length direction of the shell body, and is connected to the two cavity skeleton units.

6. The lower housing of the battery pack according to claim 5, characterized in that, The cross-section of the avoidance area is an inverted U-shaped structure, and the cross-section of the arc-shaped reinforcing unit is a Z-shaped structure; Along the width direction of the shell body, at least a portion of the cross-section of the arc-shaped reinforcing unit is fitted to the surface contour of the avoidance area.

7. The lower housing of the battery pack according to claim 6, characterized in that, Along the width direction of the shell body, at least a portion of the cross-section of the arc-shaped reinforcing unit is spaced apart from the cross-section of the avoidance area, so that a pressure-resistant cavity is formed between the arc-shaped reinforcing unit and the shell body.

8. The lower housing of the battery pack according to claim 5, characterized in that, The cavity skeleton unit includes: A transverse reinforcing unit extends along the width direction of the shell body and is fixedly connected to the bottom of the first cavity structure and the second cavity structure; The longitudinal reinforcing unit extends along the length of the shell body and intersects with the transverse reinforcing unit and / or the arc-shaped reinforcing unit to form a reinforcing grid structure.

9. The lower housing of the battery pack according to claim 8, characterized in that, The longitudinal reinforcing units are all disposed on both sides of the transverse reinforcing unit; The transverse reinforcing unit is provided with a first reinforcing rib; The longitudinal reinforcing unit is provided with a second reinforcing rib; And / or the bottom of the shell body is provided with a plurality of inwardly protruding reinforcing bosses.

10. A battery pack, characterized in that, Includes the lower housing of the battery pack as described in any one of claims 1-9.

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