A power battery assembly, a vehicle having the power battery assembly, and an assembling method

Abstract

This invention relates to the field of power batteries, specifically to a power battery assembly and a vehicle having the power battery assembly, and an assembly method thereof, including a housing unit and a center-mounted unit; the housing unit includes a battery housing and a battery housing cover; the battery housing includes a housing frame and a housing crossbeam; 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 center-mounted nut is connected to the center-mounted beam; the sealing structure includes a first seal and a second seal; the first seal is connected to the center-mounted nut; the second seal is connected to the center-mounted beam; this invention, by optimizing the design of the center-mounted structure, effectively reduces the number of seals used while ensuring the strength and stability of the central mounting support of the battery pack, simplifies the sealing system structure, and reduces component costs and assembly complexity.

Description

Technical Field

[0001] This invention relates to the field of power batteries, specifically to a power battery assembly, a vehicle having the power battery assembly, and an assembly method thereof. Background Technology

[0002] With the increasing demand for integrated, lightweight, and safe battery systems, the central mounting point is gradually becoming the mainstream design direction.

[0003] The existing problems and shortcomings of the central mounting structure are mainly as follows:

[0004] Traditional mid-mounted structure design is complex, with five seals and three bolt connections. The assembly process and component dimensional accuracy requirements are high. Any seal failure or improper bolt assembly may cause the failure of the entire package sealing structure.

[0005] The central mounting structure has a complex design and many assembly parts, requiring a large assembly space, which is not conducive to structural simplification and improving the overall package volume utilization rate.

[0006] Therefore, in order to improve or solve at least one of the above-mentioned technical problems, it is necessary to optimize the structure of the existing power battery pack. Summary of the Invention

[0007] The purpose of this invention is to provide a power battery assembly that uses fewer seals and has a central mounting point.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A power battery assembly includes a housing unit and a mid-mount unit; the housing unit includes a battery housing and a battery cover; the battery housing includes a housing frame and a housing crossbeam; the mid-mount unit includes a mid-mount structure, the mid-mount structure including a mid-mount beam, a mid-mount nut, a mounting countersunk hole, and a sealing structure; the mid-mount nut is connected to the mid-mount beam and is located on the outside of the housing unit; the sealing structure includes a first seal and a second seal; the first seal is connected to the mid-mount nut; the second seal is connected to the mid-mount beam and is arranged in the area between the mid-mount beam and the battery cover; the mounting countersunk hole is provided on the housing crossbeam; the mid-mount beam is connected to the housing crossbeam through the mounting countersunk hole; the depth of the mounting countersunk hole is less than the height of the housing crossbeam.

[0010] 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.

[0011] 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.

[0012] The mounting countersunk hole is a stepped hole; the middle hanging beam is a stepped shaft.

[0013] The central hanging nut and / or the central hanging beam are provided with a sealing assembly ring groove; the first sealing element is installed on the central hanging nut through the sealing assembly ring groove; the second sealing element is installed on the central hanging beam through the sealing assembly ring groove.

[0014] The middle 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; the outer diameter of the third connecting rod is smaller than the outer diameter of the second connecting rod; the middle 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 middle hanging nut is connected to the third connecting rod.

[0015] The central hanging nut is connected to the battery box cover via a water-proof structure; the water-proof structure includes an annular groove on the central hanging nut and water-blocking ribs on the battery box cover; the water-blocking ribs are distributed around the through hole of the box cover; the water-blocking ribs are coaxially distributed with the through hole of the box cover; the inner diameter of the water-blocking ribs is not less than the inner diameter of the through hole of the box cover; the central hanging nut is sleeved on the water-blocking ribs through the annular groove; the water-blocking ribs are in the shape of an inverted frustum.

[0016] A vehicle includes a body on which the power battery assembly is disposed; the body is connected to a third link in a center-mounted beam via fasteners; a first seal is located between the center-mounted nut and the body.

[0017] The vehicle body is connected to the power battery assembly through at least two intermediate mounting structures. The mounting countersunk holes in the two intermediate mounting structures have different opening directions along the side of the box beam towards the outer wall. The third link is provided with an assembly countersunk groove. The fastener is connected in the assembly countersunk groove of the third link.

[0018] An assembly method based on the aforementioned power battery assembly, the assembly method comprising the following steps:

[0019] Step 1: Component pre-assembly: The central hanging beam rod and the second seal, as well as the central hanging nut and the first seal, are pre-assembled respectively;

[0020] Step 2: Installation of the middle hanging beam: Connect the middle hanging beam with the second seal installed in Step 2 into the installation groove of the box body crossbeam;

[0021] Step 3: Assemble the power battery assembly: After completing Step 2, install the internal components of the battery box; after the internal components of the battery box are installed, assemble the battery box cover; after assembly, connect the center nut of the first sealing component pre-installed in Step 1 to the center beam rod; at this point, the power battery assembly is assembled.

[0022] Step 4: After completing Step 3, install the assembled power battery assembly onto the vehicle body. When installing the power battery assembly, first connect the mounting structure of the power battery assembly to the vehicle body, and then connect the peripheral mounting lugs of the power battery assembly to the vehicle body.

[0023] The advantages of this invention are:

[0024] This invention discloses a power battery assembly, a vehicle having the power battery assembly, and an assembly method.

[0025] This invention optimizes the design of the central mounting structure, ensuring the strength and stability of the battery pack's central mounting support while effectively reducing the number of seals used, simplifying the sealing system structure, and lowering component costs and assembly complexity.

[0026] The mid-mounted structure adopts a countersunk hole design on the crossbeam of the battery box. The depth of the countersunk hole is less than the height of the crossbeam, which avoids the connecting structure penetrating the crossbeam. This eliminates the risk of sealing failure at the bottom of the battery box due to through holes and significantly improves the waterproof and dustproof performance of the bottom of the battery pack.

[0027] The central hanging beam is assembled from the side of the box beam. With the mechanical limiting structure of stepped shaft and stepped hole, it not only facilitates the assembly operation and reduces the requirements for operating space, but also achieves axial mechanical locking through the stepped mating surface, effectively preventing the central hanging beam from detaching from the box beam along the axis. At the same time, it avoids the problems of complicated tightening torque control and cumbersome anti-loosening measures caused by traditional threaded connection.

[0028] The mounting holes of two or more intermediate mounting structures have different opening directions on the lateral outer wall, which makes the force pattern of each mounting point mutually restrictive when the battery pack is subjected to lateral load during vehicle operation, thus enhancing the lateral anti-displacement capability and overall stability of the power battery assembly.

[0029] By combining the annular groove and the inverted frustum-shaped water-blocking rib in the waterproof structure, a labyrinthine sealing path is formed between the battery box cover and the central hanging nut, which further improves the waterproof reliability of the through hole of the box cover. Even if external water splashes or is washed under high pressure, water is difficult to seep into the battery box through the connection gap.

[0030] The assembly method clearly defines the sequence of pre-installation, lateral mounting of the rods, installation of nuts after closing the cover, and finally vehicle mounting. In particular, when installing the whole vehicle, the central mounting structure is connected first, followed by the peripheral mounting ears. This ensures that the central mounting point bears the load first and is accurately positioned, avoiding stress shift or assembly stress concentration at the central mounting point due to the peripheral mounting ears being fixed first. This helps improve the assembly accuracy and long-term reliability of the whole vehicle. Attached Figure Description

[0031] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of the present invention.

[0033] Figure 2 This is a partial enlarged view of the connection between the battery box cover and the water-blocking ribs of the present invention.

[0034] The markings in the above figures are all:

[0035] 1. Box unit, 2. Body, 3. Mid-mounted unit. Detailed Implementation

[0036] 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.

[0037] A power battery assembly includes a housing unit 1 and a center-mounted unit 3; the housing unit 1 includes a battery housing and a battery housing cover 12; the battery housing includes a housing frame and a housing crossbeam 11; the center-mounted unit 3 includes a center-mounted structure, the center-mounted structure including a center-mounted beam 31, a center-mounted nut 33, a mounting countersunk hole 32, and a sealing structure; the center-mounted nut 33 is connected to the center-mounted beam 31 and is located on the outside of the housing unit 1; the sealing structure includes a first sealing element 34 and a second sealing element 35; the first... The 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.

[0038] 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.

[0039] 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.

[0040] 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 and several housing beams 11. The housing frame serves as a skeletal support structure, and the housing beams 11 are transversely connected between the housing frames, which not only strengthen the overall rigidity and torsional resistance of the battery housing, but also provide an installation foundation for the mid-mounted unit 3.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 inner wall has multiple segments with different inner diameters along the axial direction, specifically including a large diameter segment and a small diameter segment, with an annular step surface 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] An assembly method based on the aforementioned power battery assembly, the assembly method comprising the following steps:

[0071] 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;

[0072] 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;

[0073] 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.

[0074] 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 mounting structure of the power battery assembly to the vehicle body 2, and then connect the peripheral mounting ears of the power battery assembly to the vehicle body 2.

[0075] 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.

[0076] The specific assembly process flow of this invention.

[0077] Step 1: Component pre-assembly stage.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] Step 2: Installation stage of the middle hanging beam rod 31.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] Step 3: Power battery assembly stage.

[0087] 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 includes the following three sequential sub-stages:

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] Step 4: Vehicle installation of the power battery pack.

[0093] 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:

[0094] 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.

[0095] Secondly, after completing the connection of the mid-mount structure, align the multiple mounting ears 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. The peripheral mounting ears are usually located at the edge of the battery box, and there are multiple of them distributed around the circumference of the battery pack, which serve to provide auxiliary support and anti-torsion.

[0096] 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.

[0097] The sequential arrangement in step 4, "first connecting the central mounting structure to the vehicle body 2, and then connecting the peripheral mounting ears to the vehicle body 2," has significant engineering implications. The central mounting structure, located in the central region 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 mounting ears, 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 mounting ears 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.

[0098] Example 1:

[0099] This invention provides a power battery assembly, which comprises two main parts: a housing unit 1 and a mid-mounted unit 3. The housing unit 1 forms the overall housing space of the battery pack, used to house internal core components such as the cell modules, battery management system, high-voltage connectors, and cooling system. Specifically, the housing unit 1 includes a battery housing and a battery cover 12. The battery housing is composed of a housing frame and several housing beams 11. The housing frame serves as a skeletal support structure, while the housing beams 11 connect laterally between the frames, enhancing the overall rigidity and torsional resistance of the housing, and providing a mounting base for the mid-mounted unit 3. The battery cover 12 closes onto the upper opening of the battery housing, and the two are sealed together with sealant and fasteners to protect the internal cells and electrical components from external moisture, dust, and salt spray corrosion.

[0100] 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 consisting of 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 and has a stepped shaft structure, meaning it has multiple segments with different outer diameters along the axial direction. The center-mount nut 33 is a fastener with internal threads, whose threads match the external threads 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. The mounting countersunk hole 32 is formed on the crossbeam 11 of the battery pack to accommodate and position the central hanging 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 capabilities of the battery pack.

[0101] 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 in the contact area between 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. The two seals form a double-protection sealing system, greatly improving the long-term reliability of the entire mounting structure under complex and harsh working conditions.

[0102] To further optimize the installation convenience and mechanical performance of the mid-mounted structure, this invention specifically defines the construction of the box beam 11 and the method of opening the mounting countersunk holes 32. The box beam 11 is an elongated structural member with a rectangular or near-rectangular cross-section and multiple outer wall surfaces. Among them, 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 laterally on 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 and form an edge between them.

[0103] The mounting countersunk hole 32 is not simply opened along a direction perpendicular to the first outer wall surface. Instead, it forms a channel on the box beam 11, with one opening on the first outer wall surface and the other on the lateral outer wall surface, the two openings being interconnected. This construction allows the mounting countersunk hole 32 to simultaneously communicate 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 center-mounted beam 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 strictly from top to bottom along a direction perpendicular to the first outer wall surface. The lateral opening provides operators or automated equipment with a more flexible operating angle and more ample working space, reducing assembly difficulty and improving assembly efficiency.

[0104] Meanwhile, the mounting countersunk hole 32 is further designed as a stepped hole, meaning its internal wall has multiple segments with different inner diameters along the axial direction. Correspondingly, the middle hanging beam 31 is designed as a stepped shaft, with its outer diameter corresponding to 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 shoulder on the stepped shaft abuts against the stepped surface inside the stepped hole, forming a mechanical limit.

[0105] This limiting function effectively prevents the center beam rod 31 from shifting or coming off along its axial direction. Even if the vehicle is subjected to strong vibration or impact loads during operation, the center beam rod 31 can be firmly restrained within the mounting countersunk hole 32, eliminating the need for additional anti-loosening clips 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 due to loose threads or shear breakage of pins, significantly improving the structural integrity and service safety of the mounting system.

[0106] When the power battery pack needs to be mounted and connected to the vehicle body 2 at multiple locations, two or more intermediate mounting structures are usually set up. These intermediate mounting structures are arranged on the crossbeams 11 of the battery box at different locations to achieve multi-point support and uniform load distribution. This invention proposes a further optimization scheme for the layout of multiple intermediate mounting structures.

[0107] Specifically, when the power battery pack 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 side of their respective housing crossbeams 11 are set to be opposite. That is, the first mid-mounted structure's mounting countersunk hole 32 faces the left side of the housing crossbeam 11, while the second mid-mounted structure's mounting countersunk hole 32 faces the right side of the housing crossbeam 11, or other directions such as forward or backward; in short, they do not coincide in the same direction. By setting the opening directions of different mid-mounted structures to be opposite, a mutually restrictive force pattern is formed between the various mid-mounted structures. For example, if one opening faces left and the other faces right, then when subjected to longitudinal impact, the lateral force components they experience are in opposite directions, acting as opposing constraints and effectively counteracting the pull-out 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-mid-mounted structure system under complex load environments, which is particularly important for ensuring the installation firmness of the battery pack under collision or extreme road conditions.

[0108] To ensure that the first seal 34 and the second seal 35 can stably perform their sealing function during long-term use, the present invention provides sealing assembly ring grooves 36 for accommodating the seals on the central hanging nut 33 and the central hanging beam 31, respectively. The sealing assembly ring groove 36 is an annular groove opened around the outer circumference of the rod or nut, and its cross-sectional shape is usually rectangular or trapezoidal. The width and depth of the groove bottom match the cross-sectional dimensions of the seal.

[0109] The first sealing element 34 is an O-ring or a shaped seal made of elastic material with a certain degree of compression deformation capability. Both the first sealing element 34 and the second sealing element 35 are made of high-temperature resistant, aging-resistant, and compression-resistant rubber materials, such as EPDM rubber or fluorosilicone rubber, to ensure sufficient elastic recovery force and sealing contact pressure within a wide temperature range of -40℃ to 85℃ and under long-term pressure. Through the limiting effect of the sealing assembly ring groove 36, the first sealing element 34 and the second sealing element 35 will not experience axial movement or twisting during installation and use, always maintaining the correct sealing posture, thereby ensuring the long-term stability and consistency of the sealing effect.

[0110] 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 or outer side of the battery box cover 12, playing a limiting and supporting role. During assembly, the middle hanging beam 31 is first inserted into the mounting countersunk hole 32 from the side of the box body crossbeam 11. At this time, the first connecting rod 311 is located deep in the mounting countersunk hole 32, and the second connecting rod 312 is located near the opening of the mounting countersunk hole 32. Then the battery box cover 12 is closed, and the third connecting rod 313 extends out from the cover through hole. Finally, the middle hanging nut 33 is screwed into the threaded end of the third connecting rod 313 from the outside. During the tightening process, the central hanging nut 33 presses against the battery box cover 12, and the battery box cover 12 is firmly clamped by the reverse support of the shoulder of the second connecting rod 312.

[0111] In this invention, the hanging beam rod 31 is designed as a stepped shaft structure with at least three functions: First, the cooperation between the shaft shoulder and the stepped surface of the mounting countersunk hole 32 enables the axial locking of the middle hanging beam rod 31 inside the box crossbeam 11 to prevent it from coming out; Second, the abutment between the shaft shoulder and the battery box cover 12 enables the pre-tightening positioning after the box cover is assembled, ensuring the accuracy of the cover assembly; Third, the extended section of the third connecting rod 313 provides a connection interface with the vehicle body 2 and the middle hanging nut 33, realizing the mechanical coupling between the battery pack and the whole vehicle.

[0112] To further enhance the waterproofing capability at the through-hole of the battery cover, a water-proof structure is added between the central hanging nut 33 and the battery cover 12. This water-proof structure includes an annular groove on the central hanging nut 33 and water-blocking ribs 37 on the battery cover 12.

[0113] The presence of the water-blocking ribs 37 increases the path for water to penetrate, thereby increasing the resistance and time required for water to seep in. Even under direct high-pressure water jet washing, water is unlikely to penetrate the battery box through such a complex path in a short time. This water-blocking structure, together with the first seal 34 and the second seal 35, constitutes a triple protection system of "seals + labyrinth water barrier," enabling a stable improvement in the waterproof rating of the central mounting structure.

[0114] The present invention also provides a vehicle employing the aforementioned power battery pack. The vehicle includes body structural components such as a chassis panel or longitudinal beams, and the power battery pack is fixedly installed under the vehicle body 2 or inside the vehicle body 2 via a center-mounted structure. In the installed state, the chassis panel is connected to the third link 313 of the center-mounted beam 31 via fasteners. Specifically, the third link 313 has a mounting groove 38, and the rod of the fastener passes through a mounting hole on the chassis panel and is screwed into or inserted into the mounting groove 38, thereby achieving mechanical coupling between the vehicle body 2 and the battery pack. After assembly, the first sealing member 34 is positioned between the center-mounted nut 33 and the chassis panel, and is pressed to form a sealed contact, preventing water splashed by the wheels during vehicle operation or winter snow-melting salt water from entering through the connection gap.

[0115] Specifically, the vehicle body 2 is connected to the power battery assembly through at least two intermediate mounting structures, and the mounting countersunk holes 32 of these two intermediate mounting structures have different opening directions on the outer wall side of their respective box crossbeams 11. The mechanical principle of their multi-directional constraint has been explained in detail in the aforementioned embodiments and will not be repeated here.

[0116] In the vehicle assembly process, the installation sequence of the power battery pack is explicitly defined as follows: first, connect the center mount structure to the vehicle body 2, and then connect the peripheral mounting lugs of the power battery pack to the vehicle body 2. The engineering significance of this sequence is that the center mount structure is located in the central area of ​​the battery pack. Prioritizing the center mount allows the battery pack to achieve initial precise positioning under the vehicle body 2, establishing its positional reference in the front-rear, left-right, and height directions. After this reference is established, connecting the peripheral mounting lugs located at the edge of the battery pack can lead to stress concentration or forced assembly due to the cumulative tolerances generated when multiple mounting points are simultaneously positioned. Conversely, if the peripheral mounting lugs are fixed first and then the center mount structure is connected, the center mount structure may not align properly due to manufacturing tolerances of the lugs and deviations in the mounting hole positions. Even if alignment is forced, it may introduce significant internal stress into the structure, potentially leading to fatigue cracks or loose connections during long-term use. Therefore, the assembly sequence of center mount first, then peripheral mounts, 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 driving safety and battery pack fixation reliability.

[0117] Based on the above structural design, the present invention also provides a complete power battery assembly method, which is divided into the following four main stages in logical order.

[0118] The first stage is the component pre-assembly stage. In this stage, at a specially designated pre-assembly station, the central support beam 31 and the second seal 35 are pre-assembled. Specifically, the second seal 35 is fitted into the corresponding sealing assembly ring groove 36 on the central support beam 31, ensuring that the seal is flat and extended within the groove, without twisting, flanging, or excessive stretching. Simultaneously, the central support nut 33 and the first seal 34 are pre-assembled, with the first seal 34 embedded into the sealing assembly ring groove 36 of the central support nut 33. The installation status is also checked for compliance. This pre-assembly process completes the seal installation actions, which would otherwise be performed separately during mainline assembly, in advance. This helps shorten the mainline cycle time, reduce the complexity of operations on the mainline, and improve the consistency and quality control of seal installation.

[0119] The second stage is the installation of the central hanging beam 31. After pre-installation, the operator or automated equipment inserts or pushes the central hanging beam 31, which already has the second seal 35 installed, into the installation countersunk hole 32 from the opening on the outer wall side of the box beam 11, in a direction consistent with the axis of the installation countersunk hole 32. Since the installation countersunk hole 32 is a stepped hole and the central 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 bearing shoulder and the stepped surface can be clearly felt to limit the movement, at which point the axial position of the central hanging beam 31 is precisely fixed. This installation method does not require hammering or strong pressing, the operation is smooth and stable, and it can effectively avoid the tilting of the studs or damage to the seals caused by hammering.

[0120] The third stage is the power battery assembly stage. After the central suspension beam 31 is installed, the assembly of internal components of the battery box begins. This includes placing and fixing the cell modules inside the box according to the design layout, connecting the battery management system acquisition harness, and installing high-voltage connectors, low-voltage control harnesses, cooling plates, and cooling pipes. After all internal components are installed and inspected, the battery box cover 12 is assembled. This involves applying sealant to the upper surface of the battery box, then covering it with the cover, allowing the third connecting rod 313 of the central suspension beam 31 to extend from the cover's through hole. Pressure is then applied to press the cover tightly against the box, and the sealant is allowed to cure before a preliminary airtightness test is performed. After the airtightness test is passed, the central suspension nut 33, pre-assembled in the first stage and equipped with the first sealing element 34, is screwed onto the external thread of the third connecting rod 313 and tightened to the specified torque. At this point, the internal assembly of the power battery assembly is complete.

[0121] The fourth stage is the vehicle assembly stage. The assembled battery pack is transported to the installation location under the vehicle using lifting equipment or a hoist. First, the third link 313 of the battery pack's mounting structure is aligned with the mounting holes on the vehicle's floor. Fasteners are inserted and pre-tightened to ensure precise positioning of the battery pack under the vehicle body. Next, the multiple mounting lugs around the battery pack are aligned with the corresponding mounting brackets on the vehicle body, and the surrounding fasteners are installed and tightened to the specified torque. Finally, the assembly returns to the mounting structure, and the mounting nuts 33 are retightened to the final torque, ensuring that the torque values ​​at all connection points meet 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, enabling full traceability management of assembly data and providing data support for subsequent product quality analysis and process optimization.

[0122] Through the synergistic effect of the above embodiments, the power battery assembly, vehicle and assembly method proposed in this invention have achieved significant improvements in structural strength, sealing protection, assembly efficiency and multi-directional load-bearing reliability, which can fully meet the high standard requirements of new energy vehicles for power battery systems in complex usage environments.

[0123] 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 power battery assembly, characterized in that, Includes the enclosure unit and the mid-mounted unit; The enclosure unit includes a battery enclosure and a battery enclosure cover; the battery enclosure includes an enclosure frame and an enclosure crossbeam; The central mounting unit includes a central mounting structure, which includes a central mounting beam, a central mounting 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.

2. The power battery assembly according to claim 1, 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.

3. 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.

4. A power battery assembly according to any one of claims 1-3, characterized in that, The mounting countersunk hole is a stepped hole; the middle hanging beam is a stepped shaft.

5. A power battery assembly according to any one of claims 1-3, characterized in that, The central hanging nut and / or the central hanging beam are provided with a sealing assembly ring groove; the first sealing element is installed on the central hanging nut through the sealing assembly ring groove; the second sealing element is installed on the central hanging beam through the sealing assembly ring groove.

6. A power battery assembly according to any one of claims 1-3, characterized in that, The middle 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; the outer diameter of the third connecting rod is smaller than the outer diameter of the second connecting rod; the middle 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 middle hanging nut is connected to the third connecting rod.

7. A power battery assembly according to claim 6, characterized in that, The central hanging nut is connected to the battery box cover via a water-proof structure; the water-proof structure includes an annular groove on the central hanging nut and water-blocking ribs on the battery box cover; the water-blocking ribs are distributed around the through hole of the box cover; the water-blocking ribs are coaxially distributed with the through hole of the box cover; the inner diameter of the water-blocking ribs is not less than the inner diameter of the through hole of the box cover; the central hanging nut is sleeved on the water-blocking ribs through the annular groove; the water-blocking ribs are in the shape of an inverted frustum.

8. A vehicle, characterized in that, The vehicle body includes a power battery assembly as described in any one of claims 1-7; the vehicle body is connected to a third link in the center suspension beam via fasteners; the first seal is located between the center suspension nut and the vehicle body.

9. A vehicle according to claim 8, characterized in that, The vehicle body is connected to the power battery assembly through at least two intermediate mounting structures. The mounting countersunk holes in the two intermediate mounting structures have different opening directions along the side of the box beam towards the outer wall. The third link is provided with an assembly countersunk groove. The fastener is connected in the assembly countersunk groove of the third link.

10. An assembly method based on the power battery assembly according to claims 1-7, characterized in that, The assembly method includes the following steps: Step 1: Component pre-assembly: The central hanging beam rod and the second seal, as well as the central hanging nut and the first seal, are pre-assembled respectively; Step 2: Installation of the middle hanging beam: Connect the middle hanging beam with the second seal installed in Step 2 into the installation groove of the box body crossbeam; Step 3: Assemble the power battery assembly: After completing Step 2, install the internal components of the battery box; after the internal components of the battery box are installed, assemble the battery box cover; after assembly, connect the center nut of the first sealing component pre-installed in Step 1 to the center beam rod; at this point, the power battery assembly is assembled. Step 4: After completing Step 3, install the assembled power battery assembly onto the vehicle body. When installing the power battery assembly, first connect the mounting structure of the power battery assembly to the vehicle body, and then connect the peripheral mounting lugs of the power battery assembly to the vehicle body.

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