A battery box, a power battery assembly with the battery box and a vehicle

Abstract

This invention relates to the field of battery packs, specifically to a battery housing, a power battery assembly having the battery housing, and a vehicle. The battery housing includes a housing frame and a housing crossbeam. The crossbeam is connected to the housing frame via a connecting unit. The crossbeam is a composite expansion beam. The connecting unit includes connecting lugs, each of which includes a first lug and a second lug. This invention replaces traditional metal crossbeams and support beams with composite expansion beams and composite support beams made of epoxy resin and glass fiber. The density of the composite material is much lower than that of metal materials (such as aluminum alloy and steel), which, while ensuring structural strength, can significantly reduce the overall weight of the battery pack's lower tray, thus helping to improve the driving range and overall energy efficiency of new energy vehicles.

Description

Technical Field

[0001] This invention relates to the field of battery packs, specifically to a battery housing, a power battery assembly having the battery housing, and a vehicle. Background Technology

[0002] Lightweighting of power battery packs is an important direction for the development of electric vehicles and a crucial means of energy conservation and emission reduction.

[0003] As a key component of electric vehicles, the battery pack's lightweight design is crucial for increasing vehicle range. However, traditional automotive batteries are large and heavy, and their semi-enclosed or fully enclosed structures are not conducive to heat dissipation and have poor corrosion resistance.

[0004] Therefore, in order to improve the above problems, it is necessary to optimize the design of the existing battery pack structure. Summary of the Invention

[0005] The purpose of this invention is to provide a lightweight battery housing.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A battery enclosure, comprising a enclosure frame and enclosure crossbeams;

[0008] The box beam can be connected to the box frame through a connecting unit;

[0009] The box-shaped crossbeam is a composite expansion beam;

[0010] The connecting unit includes connecting lugs, each connecting lug including a first lug and a second lug; the first lug and the second lug are connected.

[0011] The connecting lugs are connected to the housing frame via the first lug and to the housing beam via the second lug.

[0012] The connecting unit includes two connecting lugs, which are distributed opposite to each other; both ends of each box beam can be connected to the box frame through the connecting unit.

[0013] The box body beam includes a main beam body; the end of the main beam body is provided with an overlapping protrusion; the vertical cross section of the box body beam is T-shaped; the two ends of the box body beam can be overlapped with the box body frame through the overlapping protrusion.

[0014] The main body of the crossbeam is provided with a lateral overlapping beam on its side; the box frame also includes a support structure, which includes multiple composite support beams; adjacent composite support beams are distributed at intervals; one end of the composite support is connected to the box frame, and the other end is connected to the lateral overlapping beam in the adjacent box crossbeam.

[0015] The battery housing also includes a liquid cooling plate; the liquid cooling plate is provided with a positioning groove; the connecting lugs protrude from the housing frame; the connecting lugs can be inserted into the positioning grooves of the liquid cooling plate; each connecting lug has a corresponding positioning groove.

[0016] The housing frame is provided with a lifting lug unit, which includes two end lifting lug structures and two side lifting lug structures; the two end lifting lug structures are symmetrically distributed on both sides of the housing frame; the two side lifting lug structures are symmetrically distributed on both sides of the housing frame; each end lifting lug structure includes at least one end lifting lug; each side lifting lug structure includes at least one side lifting lug, and adjacent end lifting lug structures and side lifting lug structures are staggered.

[0017] A power battery assembly, characterized in that it includes a housing unit and a center-mounted unit; the housing unit includes a battery housing and a battery housing cover; the center-mounted unit includes a center-mounted structure, the center-mounted structure including a center-mounted beam, a center-mounted nut, a mounting countersunk hole, and a sealing structure;

[0018] The central hanging nut is connected to the central hanging beam and is located on the outside of the box unit;

[0019] The sealing structure includes a first sealing element and a second sealing element;

[0020] The first seal is connected to the central hanging nut;

[0021] The second seal is connected to the central suspension beam and is located in the area between the central suspension beam and the battery box cover;

[0022] The mounting countersunk hole is set on the box body crossbeam; the middle hanging beam is connected to the box body crossbeam through the mounting countersunk hole; the depth of the mounting countersunk hole is less than the height of the box body crossbeam.

[0023] The box beam has an intersecting first outer wall surface and a lateral outer wall surface. The first outer wall surface is adjacent to the battery box cover, and the lateral outer wall surface is located on the side of the box beam. The mounting countersunk hole in each hanging structure simultaneously penetrates the first outer wall surface and the lateral outer wall surface of the box beam it connects to, and the mounting countersunk hole is respectively connected to the outer side of the first outer wall surface and the outer side of the lateral outer wall surface of the connected box beam.

[0024] The power battery assembly includes at least one center-mounted structure; when the power battery assembly has two or more mounting structures, the mounting countersunk holes of any two mounting structures have different opening directions along the side of the box beam towards the outer wall; the center-mounted beam rod of the center-mounted structure can be assembled onto the box beam through the opening on the side of the box beam towards the outer wall.

[0025] The mounting counterbore is a stepped hole; the middle suspension beam rod is a stepped shaft; the middle suspension beam rod comprises a first connecting rod, a second connecting rod and a third connecting rod; the two ends of the second connecting rod are respectively provided with the first connecting rod and the third connecting rod; the outer diameter of the third connecting rod is smaller than the outer diameter of the second connecting rod; the middle suspension beam rod is penetratingly connected to the battery box cover through the third connecting rod; the battery box cover is provided with a box cover penetrating hole for the third connecting rod to pass through; the middle suspension nut is connected to the third connecting rod.

[0026] A vehicle comprises a vehicle body, wherein the vehicle body is provided with the power battery assembly; the vehicle body is connected to the third connecting rod in the middle suspension beam rod through a fastener; the first sealing member is positioned between the middle suspension nut and the vehicle body; the vehicle body is connected with the power battery assembly through at least two middle suspension structures, and the opening directions of the mounting counterbores in the two middle suspension structures along the outward side wall surface of the box cross beam are different; the third connecting rod is provided with an assembly counterbore; the fastener is connected into the assembly counterbore of the third connecting rod.

[0027] The advantages of the present invention lie in:

[0028] The present invention discloses a battery box, and a power battery assembly and a vehicle having the same.

[0029] By using the composite material expansion beam and the composite material support beam made of composite materials such as epoxy resin and glass fiber to replace the traditional metal cross beam and support beam. The density of composite materials is much lower than that of metal materials (such as aluminum alloy and steel), and on the premise of ensuring structural strength, the overall weight of the lower tray of the battery pack can be greatly reduced, which is conducive to improving the cruising range and vehicle energy efficiency of new energy vehicles.

[0030] The composite material beams (composite material expansion beam and composite material support beam) are integrally formed by a pultrusion process, and have the characteristics of high specific strength and high specific modulus. The cavity cross-section design (such as "square" shape, "day" shape, etc.) is uniformly and symmetrically distributed, which can effectively avoid stress concentration, ensure stable structural strength, and meet the requirements of the battery pack for stiffness and impact resistance while realizing lightweight.

[0031] The composite material itself has excellent insulation performance. Compared with the metal structural beam, it can effectively block the conductive path between the cells or high-voltage electrical components and the box frame, reduce the risk of electric leakage and short circuit, and improve the electrical safety level of the battery pack.

[0032] The composite material has excellent corrosion resistance, can resist harsh working conditions such as electrolyte leakage, coolant erosion and road gravel impact, and will not have the rust problem of metal materials after long-term use, thereby prolonging the service life and reliability of the battery pack.

[0033] The composite material pultrusion process is suitable for large-scale continuous production and eliminates the need for complex subsequent machining processes. Furthermore, the composite beams and metal frames can be flexibly connected using various methods such as riveting, gluing, bolting, or snap-fitting, eliminating the need for welding and simplifying the assembly process while reducing production equipment and labor costs.

[0034] The liquid cooling plate is located between the housing frame and the bottom protective plate, and is fixed by a combination of adhesive and riveting. This ensures both the robustness of the multiple connections and the airtightness of the housing. The connection between the bottom protective plate and the housing frame forms an open-top cavity, providing a well-organized area for the cell modules, electrical structure, and thermal management devices. This facilitates uniform heat dissipation from the liquid cooling plate and ensures that the battery pack operates at an appropriate temperature. Attached Figure Description

[0035] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0036] Figure 1 This is an overall block diagram of the battery box of the present invention;

[0037] Figure 2 This is an exploded view of the battery box of the present invention.

[0038] Figure 3 This is a schematic diagram of the structure when the connecting ear plate and the liquid cooling plate of the present invention are connected.

[0039] Figure 4 This is a partial structural diagram of the present invention when a central hanging structure is connected to the crossbeam of the box body.

[0040] The markings in the above figures are all:

[0041] 1. Box unit, 2. Body, 3. Mid-mounted unit, 4. Underbody protection plate, 5. Liquid cooling plate, 6. Connecting unit, 7. Composite support beam, 8. End lifting lug structure, 9. Side lifting lug structure. Detailed Implementation

[0042] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0043] As shown in the figure, the present invention provides a battery box, which is particularly suitable for the CTP (Cell to Pack) battery pack structure of new energy vehicles. Its overall structure mainly includes a box frame 13, a box beam 11, a liquid cooling plate 5, and a lifting lug unit.

[0044] The housing frame 13 serves as the main supporting skeleton of the entire battery housing. It consists of a front frame 131, a left frame 134, a rear frame 133, and a right frame 132, which are welded together to form a "U"-shaped structure. These four frames are preferably made of aluminum alloy profiles and are fixedly connected by a welding process to form a stable rectangular outer contour, providing an installation reference for the internal components. The internal space of the housing frame 13 is used to accommodate the battery cell modules, electrical devices, and thermal management components.

[0045] The transverse beam 11 is disposed inside the housing frame 13, spanning between the left side frame 134 and the right side frame 132, or between the front side frame 131 and the rear side frame 133. Its function is to increase the overall bending and torsional stiffness of the housing frame 13. In this embodiment, the transverse beam 11 is specifically a composite expansion beam, which is made of a composite of high-molecular synthetic resin (such as epoxy resin) and glass fiber reinforcement material, and integrally formed by pultrusion process. This composite expansion beam has the characteristics of light weight, high strength, good insulation and excellent corrosion resistance, which can significantly reduce the overall weight of the battery housing while ensuring the structural load-bearing capacity.

[0046] To achieve a reliable connection between the composite expansion beam and the metal box frame 13, this invention provides a dedicated connection unit 6. Each connection unit 6 includes two connecting lugs 61, which are distributed opposite to each other. Each connecting lug 61 includes a first lug 611 and a second lug 612, which are fixedly connected as a single unit. These lugs can be integrally bent or welded together. During installation, the first lug 611 is fitted against the inner side of the box frame 13's frame edge and fixedly connected to the box frame 13 by welding or bolts; the second lug 612 is used to connect to the ends of the box beams 11. In this way, both ends of each box beam 11 are fixedly connected to the box frame 13 through their respective connection units 6.

[0047] The two connecting lugs 61 are distributed symmetrically at intervals, forming an assembly gap between them, which facilitates the placement of the box beam 11.

[0048] Furthermore, the box-type crossbeam 11 includes a main body, with an overlapping protrusion at the end of the main body. This overlapping protrusion extends outward from the end face of the main body, and the vertical cross-section of the main body is T-shaped. The upper horizontal side of the T-shape is the overlapping protrusion, and the lower vertical side is the load-bearing part of the main body. During assembly, both ends of the box-type crossbeam 11 overlap with the upper surface of the box-type frame 13 via the overlapping protrusion. This T-shaped overlapping structure increases the contact area between the end of the crossbeam and the box-type frame 13, which helps to distribute the load and reduce local stress. Furthermore, the overlapping protrusion provides auxiliary positioning and limiting functions, preventing the crossbeam from shifting horizontally, thus ensuring assembly accuracy and connection stability. After the overlap is completed, the main body of the crossbeam and the box-type frame 13 are further locked and fixed by the second ear plate 612 in the aforementioned connecting unit 6, forming a double connection guarantee.

[0049] The enclosure frame 13 also includes a support structure that provides mounting points for electrical components, wiring harnesses, or thermal management devices within the battery enclosure. The support structure comprises multiple composite support beams 7, which are also made of a composite material of high-molecular synthetic resin and glass fiber, preferably formed by pultrusion, resulting in a lightweight and high-strength structure. Adjacent composite support beams 7 are spaced apart, forming multiple parallel support tracks, facilitating the partitioned arrangement of multiple electronic components.

[0050] To effectively connect the composite support beam 7 to the box body crossbeam 11, this embodiment provides a lateral overlapping beam 111 on the side of the crossbeam body. The lateral overlapping beam 111 can be a wing plate structure protruding outward from the side wall of the crossbeam body, or it can be an independent component fixed to the side of the crossbeam body by fasteners. One end of the composite support beam 7 is connected to the front frame 131 or the rear frame 133 of the box body frame 13, and its connection method can adopt the same ear plate riveting or bolting structure as the aforementioned connection unit 6; the other end of the composite support beam 7 is connected to the lateral overlapping beam 111 of the adjacent box body crossbeam 11, which can be fixed by bolts, rivets or snap-fit ​​methods.

[0051] Through the aforementioned connection method, the box beam 11 and the composite support beam 7 form a grid-like three-dimensional support skeleton inside the box frame 13. The box beam 11, as the main load-bearing beam, bears the main bending and torsional loads; the composite support beam 7, as an auxiliary support beam, provides a foundation for component installation while also distributing loads and enhancing the overall structural rigidity. The synergistic cooperation between the two ensures a more uniform stress distribution within the entire battery box structure, preventing load concentration on a single beam and thus improving the battery box's ability to resist vibration and impact during vehicle operation.

[0052] The battery housing also includes a liquid cooling plate 5, which is located below the housing frame 13 and is used for thermal management of the cells or battery modules housed in the housing. The coolant flowing through the inside of the liquid cooling plate 5 carries away the heat generated during the charging and discharging of the cells, ensuring that the battery pack operates within a suitable temperature range. The battery housing also includes a bottom protective plate 4, which is connected to the battery frame 13. The liquid cooling plate is located between the bottom protective plate 4 and the battery frame 13.

[0053] In this embodiment, the liquid cooling plate 5 is provided with a positioning groove 51. The shape and size of the positioning groove 51 match the protruding part of the connecting ear plate 61. Specifically, after the connecting ear plate 61 is installed, a part of its structure protrudes from the edge surface of the housing frame 13, forming a protrusion. During the assembly of the liquid cooling plate 5, the liquid cooling plate 5 approaches the housing frame 13 from bottom to top, so that the protrusion of the connecting ear plate 61 is precisely inserted into the positioning groove 51 of the liquid cooling plate 5. Each connecting ear plate 61 corresponds to one positioning groove 51, that is, the number of positioning grooves 51 on the liquid cooling plate 5 is the same as the number of connecting ear plates 61.

[0054] This plug-in fit offers several advantages. First, the plug-in fit between the positioning groove 51 and the connecting ear plate 61 acts as an assembly guide, quickly positioning the liquid cooling plate 5 to the correct installation position and improving assembly efficiency. Second, this plug-in structure restricts the displacement of the liquid cooling plate 5 in the horizontal plane, preventing it from shifting due to vibration during use and ensuring the stability of the contact area and heat transfer effect between the liquid cooling plate 5 and the bottom of the upper battery cell module. Third, the connecting ear plate 61 serves both as a connector between the crossbeam and the frame and as a positioning component for the liquid cooling plate 5, achieving multifunctionality within the same structural component, simplifying the number of parts, and reducing costs.

[0055] Regarding the fixing of the liquid cooling plate 5 to the housing frame 13, this embodiment adopts a combination of adhesive bonding and riveting (i.e., adhesive-riveting combination). First, structural adhesive is applied between the bottom surface of the housing frame 13 and the mating surface of the liquid cooling plate 5. Then, the liquid cooling plate 5 is accurately placed through the positioning groove 51. Finally, the liquid cooling plate 5 is riveted and fixed to the frame of the housing frame 13 using rivets. The adhesive layer can buffer vibration and impact and play an auxiliary sealing role, while the riveting provides a strong mechanical connection. The combination of the two ensures the reliability of the fixing of multiple parts and the sealing of the bottom of the housing.

[0056] To facilitate the fixed installation of the battery box onto the vehicle chassis, the box frame 13 is equipped with a lifting lug unit. The lifting lug unit includes two end lifting lug structures 8 and two side lifting lug structures 9. The two end lifting lug structures 8 are symmetrically distributed on the front and rear sides of the box frame 13, with one end lifting lug structure 8 located on the front frame 131 and the other on the rear frame 133. The two side lifting lug structures 9 are symmetrically distributed on the left and right sides of the box frame 13, with one side lifting lug structure 9 located on the left frame 134 and the other on the right frame 132. In actual design, two end lifting lug structures 8 are each installed on the front frame 131 and the rear frame 133, while two side lifting lug structures 9 are generally installed on the rear frame 133 and the left frame 134.

[0057] Each end lug structure 8 includes at least one end lug 81, and each side lug structure 9 includes at least one side lug 91. Both the end lug 81 and the side lug 91 can be formed by bending metal sheets and fixed to their respective frames by welding. The welding positions and welding process parameters can be adjusted according to strength requirements. Mounting holes are provided on the lugs for inserting bolts to secure the battery box to the vehicle's longitudinal or transverse beams.

[0058] The adjacent end lug structures 8 and lateral lug structures 9 are staggered. This staggered distribution means that, on the horizontal projection plane, the end lugs 81 and lateral lugs 91 are not located on the same horizontal plane, but are arranged alternately and at intervals along the circumference of the battery box frame 13. For example, the end lug 81 is located at the left end of the front frame 131, and the lateral lug 91 is located at the front end of the left frame 134, forming a staggered arrangement at the corner rather than overlapping. This staggered layout has the following advantages: First, it avoids excessive local stress caused by multiple lugs concentrated in the same corner of the frame, allowing the suspended load to be more evenly distributed across the entire battery box frame 13; second, during vehicle assembly, it effectively avoids suspension mounting points or pipeline routing paths on the chassis longitudinal beams, improving the flexibility of the vehicle layout; third, multiple lugs constrain the battery box from different positions, forming a multi-point, multi-dimensional fixing method, which can better resist the vertical, longitudinal, and lateral acceleration impacts generated during vehicle operation, improving the stability and safety of the connection between the battery box and the vehicle.

[0059] A power battery assembly includes a housing unit 1 and a mid-mounted unit 3. The housing unit 1 includes a battery housing and a battery housing cover 12. The battery housing includes a housing frame 13 and a housing crossbeam 11. The mid-mounted unit is connected to the housing crossbeam 11. The mid-mounted unit 3 includes a mid-mounted structure, which includes a mid-mounted beam 31, a mid-mounted nut 33, a mounting countersunk hole 32, and a sealing structure. The mid-mounted nut 33 is connected to the mid-mounted beam 31 and is located outside the housing unit 1. The sealing structure includes a first seal 34 and a second seal. The first sealing element 34 is connected to the central mounting nut 33; the second sealing element 35 is connected to the central mounting beam 31 and arranged in the area between the central mounting beam 31 and the battery box cover 12; the mounting countersunk hole 32 is provided on the box body crossbeam 11; the central mounting beam 31 is connected to the box body crossbeam 11 through the mounting countersunk hole 32; the depth of the mounting countersunk hole 32 is less than the height of the box body crossbeam 11; the power battery assembly disclosed in this invention, by optimizing the central mounting structure, can reduce the number of sealing elements used while ensuring the central mounting support.

[0060] In this invention, the hanging structure is connected to the crossbeam 11 of the battery box using a countersunk hole design, which can avoid the problem of the hanging structure penetrating the crossbeam 11 of the battery box affecting the sealing of the lower end of the battery box.

[0061] In this invention, the central hanging beam 31 is assembled from the side of the box body crossbeam 11, and with the stepped platform structure, it not only facilitates the lateral installation of the central hanging beam 31, but also achieves mechanical limiting and locking through the stepped cooperation, preventing the central hanging beam 31 from detaching from the box body crossbeam 11 along its axial direction; it also avoids the trouble of traditional screw connection.

[0062] The power battery assembly disclosed in this invention mainly comprises two parts: a housing unit 1 and a mid-mounted unit 3. The housing unit 1 constitutes the overall housing space of the battery pack, used to carry internal core components such as cell modules, battery management system, high-voltage connectors, and cooling system. The housing unit 1 includes a battery housing and a battery cover 12, wherein the battery housing includes a housing frame 13 and several housing beams 11. The housing frame 13 serves as a skeletal support structure, and the housing beams 11 are transversely connected between the housing frames 13, which not only strengthens the overall rigidity and torsional resistance of the battery housing, but also provides an installation foundation for the mid-mounted unit 3.

[0063] The battery box cover 12 closes to the upper opening of the battery box body. The two are sealed together by sealant and fasteners to form a sealed space to protect the internal battery cells and electrical components from external moisture, dust and salt spray.

[0064] The center mount unit 3 is a key structure for fixing the battery pack to the vehicle body 2. This center mount unit 3 includes at least one center mount structure, each of which includes a center mount beam 31, a center mount nut 33, a mounting countersunk hole 32, and a sealing structure. The center mount beam 31, as the main force-transmitting element, is made of high-strength metal. The center mount nut 33 is a threaded fastener whose thread matches the external thread at the end of the center mount beam 31, connecting to the center mount beam 31 through a threaded connection. After the center mount beam 31 protrudes from the battery box cover 12, the center mount nut 33 is screwed into the threaded end of the center mount beam 31 from the outside of the battery box cover 12, thereby pressing and fixing the battery box cover 12 to the battery box body. Simultaneously, the center mount nut 33 also bears the tensile and compressive loads when connected to the vehicle body 2.

[0065] The mounting countersunk hole 32 is formed on the crossbeam 11 of the battery pack housing to accommodate and position the center-mounted beam 31. This mounting countersunk hole 32 is a blind hole structure, and its depth is strictly controlled to be less than the overall height of the crossbeam 11. The key value of this design is that the mounting countersunk hole 32 does not penetrate the bottom wall of the crossbeam 11, thus avoiding the formation of a through hole on the bottom surface of the battery pack. This effectively eliminates the potential risk of moisture or dust seeping into the battery pack through bottom holes, significantly improving the bottom sealing and protection capability of the battery pack. At the same time, the mounting countersunk hole 32 allows the center-mounted beam 31 to be securely embedded inside the crossbeam 11, obtaining reliable axial support and ensuring that the center-mounted beam 31 will not shift or tilt when subjected to dynamic loads during vehicle operation.

[0066] The sealing structure includes a first seal 34 and a second seal 35. The first seal 34 is installed on the center mount nut 33, and its function is to form a first waterproof barrier between the center mount nut 33 and the vehicle floor, preventing external moisture from seeping in through the gap between the end face of the nut and the contact surface. The second seal 35 is installed on the center mount beam 31, specifically arranged in the area between the center mount beam 31 and the battery box cover 12. Its function is to form a second seal at the position of the center mount beam 31 and the battery box cover 12, preventing gas leakage from inside the box or intrusion of external media from this point. Through the coordinated use of the first seal 34 and the second seal 35, the long-term reliability of the entire center mount unit 3 under complex and harsh working conditions can be significantly improved.

[0067] This invention utilizes a dual-seal arrangement: a countersunk hole 32 with a depth less than the height of the crossbeam 11 of the housing; a central mounting beam 31 embedded in the countersunk hole 32; a central mounting nut 33 connected to the outside of the central mounting beam 31; and a first sealing element 34 and a second sealing element 35. This arrangement ensures sufficient structural strength and load-bearing capacity for the central mounting structure while effectively avoiding the bottom sealing hazards associated with traditional through-hole mounting. Furthermore, the dual-seal design significantly improves the waterproof and dustproof performance of the battery pack at the mounting point, thereby achieving synergistic optimization of structural strength and sealing reliability. This provides a solid guarantee for the long-term safe and reliable operation of the power battery pack in new energy vehicles.

[0068] Furthermore, in this invention, the box beam 11 has an intersecting first outer wall surface and a lateral outer wall surface. The first outer wall surface is adjacent to the battery box cover 12, and the lateral outer wall surface is located on the side of the box beam 11. Each mounting countersunk hole 32 in the central hanging structure simultaneously penetrates both the first outer wall surface and the lateral outer wall surface of the connecting box beam 11, and the mounting countersunk hole 32 communicates with the outer side of the first outer wall surface and the outer side of the lateral outer wall surface of the connected box beam 11, respectively. This invention further optimizes the structure of the box beam 11 and the way the mounting countersunk holes 32 are located. The box beam 11 is an overall elongated structural member with a rectangular or near-rectangular cross-section and multiple outer wall surfaces. The surface located on the upper side of the box beam 11 and adjacent to the battery box cover 12 is defined as the first outer wall surface, and the surface located on the side of the box beam 11 and approximately perpendicular to the first outer wall surface is defined as the lateral outer wall surface. The first outer wall surface and the lateral outer wall surface intersect, forming an edge between them.

[0069] The mounting countersunk hole 32 is not simply opened along a direction perpendicular to the first outer wall surface, but rather it is configured to penetrate both the first outer wall surface and the lateral outer wall surface. In other words, the mounting countersunk hole 32 forms an L-shaped structure on the box beam 11, with one opening on the first outer wall surface and the other opening on the lateral outer wall surface, and the two openings are interconnected. Through this construction, the mounting countersunk hole 32 maintains communication with both the outer space of the first outer wall surface and the outer space of the lateral outer wall surface. The direct effect of this design is that the middle hanging beam rod 31 can be inserted into the mounting countersunk hole 32 from the lateral direction of the box beam 11 during assembly, without having to be pressed in from top to bottom strictly along a direction perpendicular to the first outer wall surface; this avoids the problem of traditional threaded connections where the thread teeth are easily damaged due to high stress. In addition, the present invention can be directly embedded into the mounting countersunk hole 32 from the side, avoiding the situation of incomplete installation caused by insufficient tightening turns in traditional methods.

[0070] Furthermore, to ensure a stable connection between the central hanging drying rack and the mounting countersunk hole 32, this invention requires the mounting countersunk hole 32 to be further designed as a stepped hole, i.e., its internal hole wall is provided with multiple mounting protrusions 315 radially; the mounting countersunk hole 32 is further divided into a large-diameter section and a small-diameter section, with a stepped surface formed between adjacent large-diameter sections and small-diameter sections; this stepped surface can be used to limit the connection of the central hanging beam 31; correspondingly, the central hanging beam 31 is designed as a stepped shaft, with its outer diameter corresponding to the inner diameter of each section of the stepped hole. When the central hanging beam 31 is inserted into the mounting countersunk hole 32 from the side opening, the shoulder on the stepped shaft abuts against the stepped surface inside the stepped hole, forming a mechanical limit. This limiting effect can effectively prevent the central hanging beam 31 from moving or coming out along its axial direction. Even if the vehicle is subjected to strong vibration or impact loads during driving, the central hanging beam 31 can be firmly restrained in the mounting countersunk hole 32 without the need for additional anti-loosening springs or locking screws. Compared to traditional threaded connections or pin fixing methods, the stepped fit structure not only simplifies the assembly process, but also eliminates the risk of connection failure caused by loose threads or shearing breakage of pins.

[0071] In addition, although the main body of the hanging beam rod 31 in this invention is a three-section structure, in order to cooperate with the mounting protrusion 315 in the mounting countersunk hole 32, the middle hanging beam rod 31 is required to have a mounting ring groove 314; so that the second connecting rod 312 and the third connecting rod 313 themselves also have a stepped structure.

[0072] In this invention, the location and quantity of the mounting protrusion 315 and the mounting annular groove 314 are selected and designed according to actual needs.

[0073] In this invention, the power battery assembly includes at least one mid-mounted structure. When the power battery assembly has two or more mounting structures, the mounting countersunk holes 32 of any two mounting structures have different opening directions along the outer wall of the body beam 11. The mid-mounted beam rod 31 of the mid-mounted structure can be assembled onto the body beam 11 through the opening on the outer wall of the body beam 11. The power battery assembly includes at least one mid-mounted structure to meet the fixed connection requirements between the battery pack and the vehicle body 2. When the power battery assembly has two or more mid-mounted structures, the opening directions of the mounting countersunk holes 32 of any two mid-mounted structures on the outer wall of the body beam 11 are set to be different. For example, the lateral opening of the mounting countersunk hole 32 of one mid-mounted structure faces the left side of the body beam 11, while the lateral opening of the mounting countersunk hole 32 of the other mid-mounted structure faces the right side of the body beam 11, or faces forward, backward, or other directions; in short, the two do not coincide in the same direction. This differentiated opening design has important mechanical significance. During actual driving, vehicles frequently experience acceleration, braking, steering, and road bumps, which impose complex dynamic loads on the battery pack in the horizontal direction. If all the lateral openings of the mid-mounted structure are oriented in the same direction, then when the vehicle is subjected to an impact force parallel to that opening, all the mid-mounted beams 31 may simultaneously experience shear or sliding forces in the direction of the opening, posing a risk of synchronous detachment. By setting the opening directions of different mounting points to be opposite to each other, a mutually constraining force pattern is formed between the mounting points. For example, if one opening faces left and another faces right, then when subjected to longitudinal impact, the lateral force components experienced by the two are in opposite directions, acting as opposing constraints and effectively counteracting the detachment force in a single direction. This layout is equivalent to introducing a redundant constraint mechanism at the structural level, significantly enhancing the overall stability and anti-displacement capability of the multi-mounted system under complex load environments, which is particularly important for ensuring the secure installation of the battery pack in collisions or extreme road conditions.

[0074] This invention significantly improves assembly processability by simultaneously penetrating the first outer wall and the lateral outer wall of the box beam 11 through the mounting countersunk hole 32, allowing the central mounting beam 31 to be installed from the side. By setting the mounting countersunk hole 32 and the central mounting beam 31 as a stepped fit structure, mechanical locking is achieved, improving connection reliability and vibration resistance. Furthermore, by setting the lateral opening directions of two or more mounting points to be opposite, a mutually constraining relationship is formed among multiple mounting points, effectively enhancing the overall stability and anti-displacement capability of the multi-mount system under complex loads. The combined effect of these structural optimizations significantly improves the power battery assembly in terms of assembly efficiency, connection reliability, and multi-directional load-bearing stability, better meeting the high standards required for power battery installation systems in new energy vehicles.

[0075] Furthermore, in this invention, the mounting countersunk hole 32 is a stepped hole; the middle hanging beam 31 is a stepped shaft; this invention optimizes the specific structural forms of the mounting countersunk hole 32 and the middle hanging beam 31. The mounting countersunk hole 32 is set as a stepped hole, that is, its internal hole wall has multiple hole segments with different inner diameters along the axial direction, specifically including a large diameter segment and a small diameter segment, and an annular step surface is formed between adjacent large diameter segments and small diameter segments. Correspondingly, the middle hanging beam 31 is set as a stepped shaft, that is, its outer wall has multiple shaft segments with different outer diameters along the axial direction, and the outer diameter of each shaft segment forms a one-to-one matching relationship with the inner diameter of each segment of the stepped hole. When the middle hanging beam 31 is inserted into the mounting countersunk hole 32 from the side opening, the shaft segment with the larger outer diameter of the stepped shaft is accommodated in the large diameter segment of the stepped hole, and the shaft segment with the smaller outer diameter of the stepped shaft is accommodated in the small diameter segment of the stepped hole. The shoulder end face on the stepped shaft abuts against the step surface in the stepped hole, forming an axial mechanical limit. This stepped fit structure has at least three functions: First, during assembly, the stepped fit acts as a guide and positioner. When the middle hanging beam 31 is inserted, only the shaft section with the smaller outer diameter can enter the smaller diameter section, while the shaft section with the larger outer diameter is blocked by the stepped surface. The operator can clearly feel whether the insertion is in place by hand, avoiding assembly errors caused by blind pushing. Second, the abutment between the shaft shoulder and the stepped surface can effectively prevent the middle hanging beam 31 from sliding out along the axial direction of the opening, eliminating the need for additional anti-loosening clips or locking screws and other auxiliary fasteners, simplifying the structure and reducing the number of parts. Third, the stepped fit creates a multi-segment contact support between the middle hanging beam 31 and the mounting countersunk hole 32. Compared with the equal diameter fit, this increases the contact area and the stress distribution range, effectively reducing local stress concentration and improving the fatigue resistance of the connection structure under alternating loads.

[0076] In this invention, the central hanging nut 33 and / or the central hanging beam 31 are provided with a sealing assembly groove 36; the first sealing element 34 is installed on the central hanging nut 33 through the sealing assembly groove 36; the second sealing element 35 is installed on the central hanging beam 31 through the sealing assembly groove 36. This invention provides a sealing assembly groove 36 on the central hanging nut 33 and / or the central hanging beam 31 for installing and fixing the first sealing element 34 or the second sealing element 35. Specifically, the sealing assembly groove 36 is an annular groove provided at the end of the central hanging nut 33 or the central hanging beam 31, with a rectangular or trapezoidal cross-sectional shape. The depth of the sealing assembly groove 36 is less than the thickness of the first sealing element 34 or the second sealing element 35, ensuring that the first sealing element 34 or the second sealing element 35 can be embedded in the groove and reliably positioned; simultaneously, the first sealing element 34 or the second sealing element 35 can have an outward convex design.

[0077] The first seal 34 is mounted on the center mount nut 33 via the sealing assembly groove 36. During assembly, the first seal 34 is embedded within the sealing assembly groove 36, protruding from the upper surface of the center mount nut 33. During subsequent vehicle assembly, the protruding end face of the first seal 34 is pressed between the center mount nut 33 and the vehicle body floor, forming a continuous and uniform sealing contact band through the contact stress generated by elastic compression, thus preventing moisture leakage between the center mount nut 33 and the vehicle body 2. The presence of the sealing assembly groove 36 ensures that the first seal 34 will not shift, flip, or be extruded due to axial compression or radial shear during assembly and use, always maintaining the correct sealing posture and compression.

[0078] The second seal 35 is mounted on the central support beam 31 in the same manner via the sealing assembly groove 36. Specifically, it is connected to the stepped platform formed by the third connecting rod 313 and the second connecting rod 312; specifically, it is positioned in the area where the central support beam 31 and the battery box cover 12 meet. After the second seal 35 is embedded in the sealing assembly groove 36, it protrudes from the groove. When the battery box cover 12 is closed, the second seal 35 is pressed between the central support beam 31 and the battery box cover 12, forming a reliable sealing barrier that prevents internal gas from leaking outwards or external moisture from seeping into the interior of the box along the space between the central support beam 31 and the battery box cover 12.

[0079] The structural design of the sealing assembly annular groove 36 ensures that the first seal 34 and the second seal 35 are independently and accurately positioned in their predetermined sealing positions, enabling each seal to operate stably according to its designed compression. When the first seal 34 and the second seal 35 are present simultaneously, they form a synergistic protection system, significantly improving the reliability of the sealing in the hanging structure area of ​​the power battery assembly.

[0080] Furthermore, in this invention, the middle hanging beam 31 includes a first connecting rod 311, a second connecting rod 312, and a third connecting rod 313; the second connecting rod 312 has a first connecting rod 311 and a third connecting rod 313 at both ends; the outer diameter of the third connecting rod 313 is smaller than the outer diameter of the second connecting rod 312; the middle hanging beam 31 is connected to the battery box cover 12 through the third connecting rod 313; the battery box cover 12 has a cover through hole for the third connecting rod 313 to pass through; the middle hanging nut 33 is connected to the third connecting rod 313. The first connecting rod 311 is located at one end near the inside of the box body crossbeam 11, and its outer diameter is adapted to the inside of the mounting countersunk hole 32, used to insert into the bottom of the mounting countersunk hole 32 to achieve lower end installation positioning, and is the first-level load-bearing section. The second connecting rod 312 is the middle section, and its outer diameter can be larger or smaller than that of the first connecting rod 311. A shoulder is required at the connection between the first connecting rod 311 and the second connecting rod 312. This shoulder can also be used for the installation limit of the middle suspension beam 31. The third connecting rod 313 is one end extending out of the outer side of the battery box cover 12. Its outer diameter is smaller than that of the second connecting rod 312, forming a second-level shoulder. This shoulder is used to abut against the periphery of the through hole of the battery box cover 12 or the end face of the vehicle body floor, playing a limiting and supporting role.

[0081] In this invention, the third link 313 is provided with an installation annular groove 314 at one end near the second link 312; an installation protrusion 315 is provided on the inner wall of the installation countersunk hole 32, and the installation annular groove 314 in the third link 313 is sleeved on the installation protrusion 315; this can play a good role in hooking and limiting; similarly, the second link 312 can also be provided with an installation protrusion 315 structure as needed.

[0082] A cover through hole is provided on the battery box cover 12 at the position where the middle hanging beam 31 passes through. The inner diameter of the through hole is slightly larger than the outer diameter of the third connecting rod 313 so that the third connecting rod 313 can pass through smoothly, but smaller than the outer diameter of the second connecting rod 312, so that the shoulder between the second connecting rod 312 and the third connecting rod 313 can be locked on the inner side of the battery box cover 12, playing a limiting and supporting role.

[0083] This invention achieves mechanical locking and precise positioning of the central mounting beam 31 within the transverse beam 11 of the battery pack by setting the mounting countersunk hole 32 as a stepped hole and the central mounting beam 31 as a stepped shaft. By providing sealing assembly grooves 36 on the central mounting nut 33 and / or the central mounting beam 31, the installation accuracy and long-term operational stability of the first seal 34 and the second seal 35 are ensured, forming a dual-redundant sealing protection system. Furthermore, by configuring the central mounting beam 31 as a multi-segment stepped shaft structure with the first connecting rod 311, the second connecting rod 312, and the third connecting rod 313 connected in sequence, it achieves internal fixation with the transverse beam 11, positioning with the battery box cover 12, and external connection with the vehicle body 2 and the central mounting nut 33, with each segment having a clear function and reasonable division of labor. These structural features work together to ensure that the central mounting structure of the power battery pack achieves excellent levels in terms of assembly convenience, connection reliability, sealing protection, and multi-directional load-bearing capacity.

[0084] Furthermore, in this invention, the central hanging nut 33 is connected to the battery box cover 12 via a water-proof structure. This invention adds a water-proof structure between the central hanging nut 33 and the battery box cover 12 to further enhance the waterproof capability of the battery box cover 12's through-hole location. The water-proof structure includes an annular groove on the central hanging nut 33 and water-blocking ribs 37 on the battery box cover 12. The water-blocking ribs 37 are distributed around the through-hole of the cover. The water-blocking ribs 37 are coaxially distributed with the through-hole of the cover. The inner diameter of the water-blocking ribs 37 is not less than the inner diameter of the through-hole of the cover. The central hanging nut 33 is fitted onto the water-blocking ribs 37 via the annular groove. The water-blocking ribs 37 are in the shape of an inverted frustum. This invention, through the annular groove and the water-blocking ribs 37 on the battery box cover 12, forms a labyrinthine sealing path, increasing the difficulty for external water to enter the through-hole of the cover, thereby improving the waterproof capability of the through-hole of the battery box cover 12.

[0085] The water-blocking rib 37 is an annular protrusion integrally formed or fixedly connected to the surface of the battery box cover 12. It is distributed around the through hole of the cover and is arranged coaxially with the through hole. The inner diameter of the water-blocking rib 37 is set to be no less than the inner diameter of the through hole of the cover, so that the through hole is located within the enclosure of the water-blocking rib 37. The water-blocking rib 37 surrounds the periphery of the through hole, forming an annular dam protruding from the outer surface of the battery box cover 12. The central hanging nut 33 has a corresponding annular groove on one end face facing the battery box cover 12. The annular groove is an annular groove formed around the center of the end face of the central hanging nut 33. Its radial width and axial depth match the radial thickness and axial height of the water-blocking rib 37, so that when the central hanging nut 33 is tightened, the annular groove can fit over the outside of the water-blocking rib 37 to form a nested fit structure; at the same time, there is no rotational interference.

[0086] When the annular groove is fitted onto the water-blocking rib 37, the water-blocking rib 37 is inserted into the annular groove, forming an overlapping mating area between them. Within this mating area, the inner and outer peripheral walls of the annular groove are respectively positioned opposite to the inner and outer wall surfaces of the water-blocking rib 37, maintaining a small gap or forming a tortuous gap channel. Because the water-blocking rib 37 has an inverted frustum-shaped structure, that is, its outer peripheral wall gradually tapers inward from the top to the root, forming a conical surface; this design makes the outer surface of the water-blocking rib 37 form an inclined surface, increasing the water immersion velocity.

[0087] In summary, the present invention provides an annular groove on the central hanging nut 33 and an inverted frustum-shaped water-blocking rib 37 on the battery box cover 12, forming a labyrinth-like sealing structure with a conical nested fit. This effectively extends the path of water infiltration and increases the difficulty for water to pass through the water-blocking structure and enter the hole of the cover.

[0088] A vehicle includes a body 2, on which the power battery assembly is mounted; the body 2 is connected to a third link 313 in a central suspension beam 31 via fasteners; a first seal 34 is located between a central suspension nut 33 and the body 2; the vehicle disclosed in this invention includes a body 2, specifically including a body floor or body longitudinal beams and other body structural components, and the power battery assembly is fixedly mounted under the body 2 via a central suspension structure. The body 2 is connected to the third link 313 in the central suspension beam 31 via fasteners, thereby achieving mechanical coupling between the power battery assembly and the vehicle. Specifically, the third link 313 is provided with a mounting groove 38, which is a recessed structure formed on the end face of the third link 313 for accommodating and installing fasteners. The fasteners pass through mounting holes on the body floor and extend into the mounting groove 38 of the third link 313, fixing the body 2 to the central suspension beam 31. This achieves the fixed mounting of the power battery assembly on the body 2.

[0089] With the power battery pack mounted on the vehicle body 2, the first seal 34 is positioned between the center mount nut 33 and the vehicle body 2. Specifically, the first seal 34 is pressed between the end face of the center mount nut 33 facing the vehicle body 2 and the corresponding surface of the vehicle body floor. When the center mount nut 33 is tightened on the third link 313, the center mount nut 33 applies a clamping force towards the vehicle body floor. Under this clamping force, the first seal 34 undergoes elastic compression deformation, and its compression is controlled within the design range. After compression, the first seal 34 forms continuous sealing contact bands in the area where it contacts the end face of the center mount nut 33 and in the area where it contacts the surface of the vehicle body floor, effectively preventing moisture, dust, or salt spray from seeping into the connection gap between the center mount nut 33 and the vehicle body floor. Since the vehicle body floor is directly exposed to the harsh external environment under the vehicle, mud splashed by the wheels, winter snowmelt salt water, and road sand and gravel can all corrode the connection point. The presence of the first seal 34 provides reliable protection for this critical connection interface.

[0090] In this invention, the vehicle body 2 is connected to the power battery assembly through at least two intermediate mounting structures. The mounting countersunk holes 32 in the two intermediate mounting structures have different opening directions along the outer wall of the body beam 11. The third connecting rod 313 is provided with a mounting groove 38. The fastener is connected to the mounting groove 38 of the third connecting rod 313. The vehicle body 2 is connected to the power battery assembly through at least two intermediate mounting structures to achieve multi-point support and uniform load distribution. The mounting countersunk holes 32 in the two intermediate mounting structures have different opening directions along the outer wall of their respective body beams 11. The mechanical significance of this differentiated opening design is particularly prominent between multiple mounting points. When longitudinal acceleration or braking loads are generated during vehicle operation, the two intermediate mounting structures with different opening directions are subjected to lateral forces in different directions, forming a force pattern of mutual opposite constraints. For example, when the vehicle brakes suddenly, the battery pack tends to move forward due to inertia. This tendency is transmitted to the vehicle body 2 through the two mounting structures. Since the lateral openings of the mounting holes 32 at the two mounting points are opposite, the constraint forces they generate in the horizontal plane are perpendicular or opposite to each other. This effectively suppresses the rotational and unidirectional slippage tendencies of the battery pack in the horizontal plane, ensuring that the battery pack receives positive constraint from at least one mounting point under impact loads in any direction. There is no situation where all mounting points are simultaneously in an unconstrained direction. This arrangement is equivalent to introducing a redundant constraint mechanism at the structural level, significantly enhancing the overall stability and anti-displacement capability of the multi-mounting-point system under complex load environments.

[0091] The present invention achieves stable installation, reliable sealing and multi-directional constraint of the power battery assembly on the vehicle by fastening the vehicle body 2 to the third link 313 of the central suspension beam 31, the first seal 34 being located between the central suspension nut 33 and the vehicle body 2, the assembly groove 38 being provided on the third link 313, and the vehicle body 2 being connected to the power battery assembly through at least two central suspension structures with different opening directions.

[0092] An assembly method based on the aforementioned power battery assembly, the assembly method comprising the following steps:

[0093] Step 1: Component pre-assembly: The middle hanging beam rod 31 and the second sealing element 35, as well as the middle hanging nut 33 and the first sealing element 34, are pre-assembled respectively;

[0094] Step 2: Installation of the middle hanging beam 31: Connect the middle hanging beam 31, after the second sealing element 35 has been installed in Step 2, into the installation groove of the box body crossbeam 11;

[0095] Step 3: Assemble the power battery assembly: After step 2 is completed, install the internal components of the battery box; after the internal components of the battery box are installed, assemble the battery box cover 12; after assembly, connect the center hanging nut 33 of the first sealing component 34 pre-installed in step 1 to the center hanging beam 31; at this point, the power battery assembly is assembled.

[0096] Step 4: After completing Step 3, install the assembled power battery assembly onto the vehicle body 2. When installing the power battery assembly, first connect the hanging structure of the power battery assembly to the vehicle body 2, and then connect the peripheral hangers of the power battery assembly to the vehicle body 2.

[0097] The assembly method provided by this invention organically connects four steps: component pre-assembly, installation of the center-mounted beam 31, power battery assembly, and vehicle installation, forming a complete, efficient, and quality-controllable assembly process. The modular pre-assembly in step 1 improves mainline efficiency and consistency of seal installation; the lateral assembly in step 2 improves operational convenience and seal protection; the timing arrangement in step 3 ensures the orderly connection and quality verification of each sub-process; and the installation sequence of center-mounted beam 31 followed by peripheral beams in step 4 guarantees assembly accuracy and reduces assembly stress. Each step is interconnected and logically rigorous, collectively achieving full-process quality control and improved production efficiency for the power battery assembly from component to vehicle installation, demonstrating significant industrial practical value and promising application prospects.

[0098] The specific assembly process flow of this invention.

[0099] Step 1: Component pre-assembly stage.

[0100] In step 1, modular pre-assembly of components is carried out, which includes two parallel sub-processes: pre-assembling the middle hanging beam 31 with the second sealing element 35, and pre-assembling the middle hanging nut 33 with the first sealing element 34.

[0101] The pre-assembly of the central hanging beam 31 and the second seal 35 is carried out at a dedicated pre-assembly station. Operators or automated equipment insert the second seal 35 into the corresponding sealing assembly groove 36 on the central hanging beam 31, ensuring the seal is flat and extended within the groove without twisting, flanging, or excessive stretching. The second seal 35, relying on its own elastic contraction force, tightly conforms to the bottom of the sealing assembly groove 36, forming preliminary radial positioning, preventing axial movement or detachment during subsequent handling and assembly. Simultaneously, the central hanging nut 33 and the first seal 34 are pre-assembled. The first seal 34 is embedded in the sealing assembly groove 36 of the central hanging nut 33; its installation status also needs to be checked to ensure it is complete and continuous within the groove, without any local protrusions or depressions.

[0102] The technical significance of the component pre-assembly process is reflected in several aspects. First, by moving the installation of seals, which would otherwise be scattered throughout the main assembly line, to the pre-assembly station, the cycle time of the main assembly line is effectively shortened, improving the main line's production efficiency. Second, the pre-assembly station can be equipped with dedicated pressing tools and visual inspection equipment to specifically control the installation quality of seals, which helps improve the consistency and quality control of seal installation. Third, modular pre-assembly allows the central hanging beam rod 31 and the second seal 35, and the central hanging nut 33 and the first seal 34, to form independent component units. These component units can be cached on the line and directly retrieved when needed by the main line, reducing the complexity of main line material distribution and dependence on immediate material supply. Fourth, by inspecting the appearance quality and installation status of each seal during pre-assembly, defective seals or poorly installed components can be rejected and reworked at the pre-assembly stage, avoiding the rework costs and wasted time caused by bringing defects into the main line assembly.

[0103] Step 2: Installation stage of the middle hanging beam rod 31.

[0104] In step 2, the middle hanging beam 31, which has been pre-installed with the second sealing element 35 in step 1, is installed into the mounting countersunk hole 32 of the box body crossbeam 11.

[0105] The specific operation method is as follows: The operator or automated equipment smoothly inserts or pushes the middle hanging beam 31 into the mounting countersunk hole 32 from the opening on the outer wall side of the box beam 11. It is not necessary to press it vertically from above the battery box. Since the mounting countersunk hole 32 is a stepped hole and the middle hanging beam 31 is a stepped shaft, it is necessary to ensure that the shaft shoulder corresponds and matches the stepped surface inside the hole during insertion. When pushed into place, the end face of the shaft shoulder on the stepped shaft abuts against the stepped surface inside the stepped hole. The operator can clearly feel the insertion in place through tactile feedback or force feedback signals from the automated equipment. At this time, the axial position of the middle hanging beam 31 within the mounting countersunk hole 32 is precisely fixed.

[0106] After installation, the installation status of the central hanging beam 31 needs to be checked and confirmed, including whether the axial length of the central hanging beam 31 extending out of the box crossbeam 11 meets the design requirements, and whether the second sealing element 35 has been offset or damaged during the assembly process.

[0107] The installation method in step 2 has significant advantages over the traditional top-down vertical installation. Before the battery box is closed, the space above the battery box is often occupied by lifting points, tooling fixtures, adjacent components, or the operator's arms. Vertical installation requires a large overhead operating space, obstructs the operator's view, and is inconvenient to operate. Furthermore, traditional center-mounted assembly typically only uses threaded connections, which can lead to improper installation. In contrast, the side assembly method of this invention operates from the side of the box, providing the operator with a wide field of vision and a natural posture, thus improving accuracy and safety. Simultaneously, the side opening provides a self-guiding function for the assembly of the center-mounted beam 31; for example, a guide chamfer or guide slope can be set at the side opening of the countersunk hole 32. When the end of the center-mounted beam 31 touches the opening, the chamfer automatically guides the center-mounted beam 31 to align with the central axis of the countersunk hole 32, reducing the difficulty of alignment for the operator and improving assembly efficiency.

[0108] Step 3: Power battery assembly stage.

[0109] After the installation of the hanging beam 31 in step 2 is completed, step 3, namely the complete assembly of the power battery assembly, is carried out. This specifically includes the following three sequential sub-stages:

[0110] The first sub-stage involves the installation of internal components within the battery housing. The battery cell modules are placed inside the battery housing according to the design layout and secured. Internal components such as the battery management system's data acquisition harness, high-voltage connectors, low-voltage control harness, cooling plate, and cooling pipes are then installed. All operations in this stage are performed inside the battery housing. At this time, the battery housing cover 12 is not yet closed, and the top of the housing is open, allowing operators or automated equipment unimpeded access to complete the installation work.

[0111] The second sub-stage is the assembly of the battery box cover 12. After all internal components are installed and inspected, sealant is applied to the upper surface of the battery box, and then the battery box cover 12 is installed. During the closing process, it is necessary to ensure that the third connecting rod 313 of the central hanging beam 31 extends accurately from the through hole of the battery box cover 12, and that the shoulder between the second connecting rod 312 and the third connecting rod 313 abuts against the periphery of the through hole of the cover. After closing, uniform pressure is applied to press the battery box cover 12 tightly against the battery box, and then the sealant is allowed to cure. A preliminary airtightness test is then performed to confirm that the overall sealing performance of the battery pack meets the design requirements.

[0112] The third sub-stage is the installation of the center-mounted nut 33. After passing the airtightness test, the center-mounted nut 33, pre-installed with the first sealing element 34 in step one, is removed and aligned with the threaded end of the third connecting rod 313. It is manually screwed in several turns to ensure proper thread alignment, and then tightened gradually using a torque-controlled electric screwdriver or torque wrench according to the specified torque. During tightening, the center-mounted nut 33 applies pressure towards the battery box cover 12. Through the reverse support of the shoulder between the second connecting rod 312 and the third connecting rod 313, the battery box cover 12 and the box body crossbeam 11 are firmly clamped together. The second sealing element 35 is pressed between the center-mounted beam 31 and the through hole of the battery box cover 12, forming a sealing barrier. At this point, the assembly of the power battery assembly is complete.

[0113] In step 3, there is a strict sequential logic between the installation of internal components, the assembly of the battery box cover, and the installation of the center-mounted nut 33. Internal components must be installed before the cover is closed, because the internal space of the box is sealed after the cover is closed, preventing further operation. The center-mounted nut 33 must be installed after the cover is closed, because it is located on the outside of the battery box cover 12 and requires the third connecting rod 313 to pass through the cover before connection can be made. The application and curing of the sealant must be performed when the cover is closed, and the final tightening of the center-mounted nut 33 can only be done after the airtightness test is passed. This ensures that the sealing system reaches the designed state before applying external tightening force, avoiding the need to remove the installed center-mounted nut 33 during rework due to uncured sealant or unqualified airtightness.

[0114] Step 4: Vehicle installation of the power battery pack.

[0115] After the power battery pack assembly is completed in step 3, step 4 is performed, which involves installing the assembled power battery pack onto the vehicle body 2. This step is further subdivided into the following sub-processes:

[0116] First, the assembled battery pack is transported to its installation position at the bottom of the vehicle using lifting equipment or a hoist. After the battery pack is lifted into place, the third link 313 of the center mount structure is aligned with the corresponding mounting holes on the vehicle floor. Fasteners are then passed through the mounting holes on the vehicle floor and inserted into the mounting grooves 38 on the third link 313 to complete the initial connection between the center mount structure and the vehicle body 2 and apply pre-tightening force. This allows the battery pack to achieve initial and accurate positioning under the vehicle body 2, determining its positional references in the front-rear, left-right, and height directions.

[0117] Secondly, after completing the connection of the mid-mounted structure, align the multiple mounting lugs around the battery pack with the corresponding mounting brackets on the vehicle body 2, install the peripheral fasteners, and tighten them to the specified torque. These peripheral lugs are typically located at the edge of the battery box, and there are multiple lugs distributed circumferentially along the battery pack, serving as auxiliary support and anti-torsion functions.

[0118] Finally, return to the central mounting structure and retighten the central mounting nut 33 to the final torque to ensure that the torque values ​​at all connection points meet the design specifications. Throughout the assembly process, the tightening torque values ​​at each stage are recorded in real time and uploaded to the quality traceability system, achieving full traceability management of assembly data.

[0119] The sequential arrangement in step 4, "first connecting the central mounting structure to the vehicle body 2, and then connecting the peripheral hangers to the vehicle body 2," has significant engineering implications. The central mounting structure, located in the central area of ​​the battery pack, serves as the reference point and primary load-bearing point for the entire battery pack connection to the vehicle body 2. Prioritizing the central mounting ensures precise positioning of the battery pack beneath the vehicle body 2, establishing its spatial attitude reference. After this reference is established, the peripheral hangers located at the edge of the battery pack are then connected. This avoids stress concentration or forced assembly issues caused by cumulative tolerances from multiple mounting points being positioned simultaneously. Conversely, if the peripheral hangers are fixed first and then the central mounting structure is connected, manufacturing tolerances and mounting hole position deviations may prevent proper alignment of the central mounting structure. Even if alignment is forced, significant internal stress may be introduced into the structure, potentially leading to fatigue cracks or loose connections over long-term use. Therefore, the assembly sequence of central mounting first, followed by peripheral mounting, as defined in this invention helps ensure assembly accuracy, reduce assembly stress, extend the fatigue life of the connection structure, and improve the overall vehicle's driving safety and the battery pack's fixation reliability.

[0120] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A battery housing, characterized in that, The battery enclosure includes the enclosure frame and the enclosure beams; The box beam can be connected to the box frame through a connecting unit; The box-shaped crossbeam is a composite expansion beam; The connecting unit includes connecting lugs, each connecting lug including a first lug and a second lug; the first lug and the second lug are connected. The connecting lugs are connected to the housing frame via the first lug and to the housing beam via the second lug.

2. The battery housing according to claim 1, characterized in that, The connecting unit includes two connecting lugs, which are distributed opposite to each other; both ends of each box beam can be connected to the box frame through the connecting unit. The box body beam includes a main beam body; the end of the main beam body is provided with an overlapping protrusion; the vertical cross section of the box body beam is T-shaped; the two ends of the box body beam can be overlapped with the box body frame through the overlapping protrusion.

3. A battery housing according to claim 2, characterized in that, The main body of the crossbeam is provided with a lateral overlapping beam on its side; the box frame also includes a support structure, which includes multiple composite support beams; adjacent composite support beams are distributed at intervals; one end of the composite support is connected to the box frame, and the other end is connected to the lateral overlapping beam in the adjacent box crossbeam.

4. A battery housing according to claim 1, characterized in that, The battery housing also includes a liquid cooling plate; the liquid cooling plate is provided with a positioning groove; the connecting lugs protrude from the housing frame; the connecting lugs can be inserted into the positioning grooves of the liquid cooling plate; each connecting lug has a corresponding positioning groove.

5. A battery housing according to claim 1, characterized in that, The housing frame is provided with a lifting lug unit, which includes two end lifting lug structures and two side lifting lug structures; the two end lifting lug structures are symmetrically distributed on both sides of the housing frame; the two side lifting lug structures are symmetrically distributed on both sides of the housing frame; each end lifting lug structure includes at least one end lifting lug; each side lifting lug structure includes at least one side lifting lug, and adjacent end lifting lug structures and side lifting lug structures are staggered.

6. A power battery assembly, characterized in that, Includes the enclosure unit and the mid-mounted unit; The housing unit includes the battery housing and battery cover as described in any one of claims 1-5; the center-mounted unit includes a center-mounted structure, which includes a center-mounted beam, a center-mounted nut, a mounting countersunk hole, and a sealing structure. The central hanging nut is connected to the central hanging beam and is located on the outside of the box unit; The sealing structure includes a first sealing element and a second sealing element; The first seal is connected to the central hanging nut; The second seal is connected to the central suspension beam and is located in the area between the central suspension beam and the battery box cover; The mounting countersunk hole is set on the box body crossbeam; the middle hanging beam is connected to the box body crossbeam through the mounting countersunk hole; the depth of the mounting countersunk hole is less than the height of the box body crossbeam.

7. A power battery assembly according to claim 2, characterized in that, The box beam has an intersecting first outer wall surface and a lateral outer wall surface. The first outer wall surface is adjacent to the battery box cover, and the lateral outer wall surface is located on the side of the box beam. The mounting countersunk hole in each hanging structure simultaneously penetrates the first outer wall surface and the lateral outer wall surface of the box beam it connects to, and the mounting countersunk hole is respectively connected to the outer side of the first outer wall surface and the outer side of the lateral outer wall surface of the connected box beam.

8. A power battery assembly according to claim 2, characterized in that, The power battery assembly includes at least one center-mounted structure; when the power battery assembly has two or more mounting structures, the mounting countersunk holes of any two mounting structures have different opening directions along the side of the box beam towards the outer wall; the center-mounted beam rod of the center-mounted structure can be assembled onto the box beam through the opening on the side of the box beam towards the outer wall.

9. A power battery assembly according to any one of claims 1-3, characterized in that, The mounting countersunk hole is a stepped hole; the central hanging beam is a stepped shaft; the central hanging beam includes a first connecting rod, a second connecting rod, and a third connecting rod; the second connecting rod has a first connecting rod and a third connecting rod at both ends respectively; the outer diameter of the third connecting rod is smaller than the outer diameter of the second connecting rod; the central hanging beam is connected to the battery box cover through the third connecting rod; the battery box cover has a cover through hole for the third connecting rod to pass through; the central hanging nut is connected to the third connecting rod.

10. A vehicle, characterized in that, The device includes a vehicle body, on which a power battery assembly as described in any one of claims 6-9 is provided; the vehicle body is connected to a third link in the center-mounted beam via fasteners; the first seal is located between the center-mounted nut and the vehicle body; the vehicle body is connected to the power battery assembly via at least two center-mounted structures, wherein the mounting countersunk holes in the two center-mounted structures have opposite opening directions along the side of the box beam towards the outer wall; the third link is provided with a mounting groove; and the fasteners are connected to the mounting groove of the third link.

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