A soft package battery module structure for electric bicycles

Abstract

This invention discloses a soft-pack battery module structure for electric bicycles, belonging to the field of power battery technology. The module structure includes: a plurality of soft-pack cells arranged along a first stacking direction; an end plate disposed at the end of the cell stacking direction; and a side plate disposed on the side of the cell stacking direction. Both ends of the side plate have extensions perpendicular to themselves, which partially surround the outer edge of the end plate. The extensions and the end plate are detachably connected by fasteners, and together they form a rigid protective frame surrounding all the cells. This invention has the advantages of adaptively compensating for cell expansion clamping force to extend battery cycle life, high insulation protection reliability, modular and detachable design for low maintenance costs, and strong versatility to meet various configuration requirements.

Description

Technical Field

[0001] This invention belongs to the field of power battery technology, specifically relating to a soft-pack battery module structure for electric bicycles. Background Technology

[0002] Electric bicycles, as a low-carbon short-distance transportation tool, have seen a continuous expansion in application scale in recent years. Soft-pack lithium-ion batteries, due to their high energy density, light weight, and flexible shaping, are widely used as the power source for electric bicycles. However, soft-pack cells undergo continuous volume expansion during cycling, and modules need to balance assembly efficiency, maintenance costs, and safety protection, resulting in several shortcomings in existing structures. When soft-pack cells are stacked and assembled into modules, if a welded rigid frame is used, it cannot be disassembled; if a single component fails, the entire module must be scrapped, leading to extremely high maintenance costs. If ordinary bolt connections are used, special tooling is required for alignment, resulting in low assembly efficiency. Furthermore, the clamping force rapidly decreases after long-term cyclic expansion of the cells, easily causing electrode misalignment damage and leakage at the sealing edges. Additionally, most modules lack built-in thermal runaway suppression structures, posing a fire risk under extreme conditions. Adapting to different configuration requirements necessitates re-molding the top structure, increasing production costs.

[0003] Most existing battery modules adopt a side-plate horizontal insertion assembly method, which makes it easy to push the stacked cells out of place during insertion. Workers need to manually guide and position them, resulting in low assembly efficiency. Furthermore, there is no expansion adaptive compensation structure, and the clamping force needs to be disassembled and readjusted after it weakens, making the operation cumbersome.

[0004] Chinese utility model patent application number CN202221987654.3 discloses a soft-pack battery module for electric bicycles, including an end plate and side plates forming a frame. Buffer foam is provided inside the end plate, and battery cells are stacked inside the frame. A protective plate is provided on top. This utility model reduces the compressive stress on the battery cells by adapting the buffer foam to the initial expansion of the cells. The applicant believes that this invention still has the following technical improvement potential: the side plates require lateral alignment during assembly, resulting in low error tolerance and easy misalignment of the battery cells, leading to insufficient assembly efficiency; passively buffering expansion with foam alone cannot adaptively compensate for the permanent compression deformation of the foam, resulting in significant attenuation of clamping force in the later stages of battery cell cycling, affecting battery life; and the lack of a built-in fire extinguishing structure means that fire cannot be quickly suppressed in the event of thermal runaway, and safety performance needs improvement. Summary of the Invention

[0005] The purpose of this application is to provide a soft-pack battery module structure for electric bicycles, which has the advantages of high assembly fault tolerance without the need for additional tooling, precise alignment and high assembly efficiency, adaptive compensation for cell expansion clamping force to extend battery cycle life, high reliability of insulation protection, excellent safety performance of built-in fire extinguishing structure, modular and detachable design with low maintenance cost, and strong versatility to meet multiple configuration requirements.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows: An electric bicycle pouch battery module structure includes: a plurality of pouch cells arranged along a first stacking direction; an end plate disposed at the end of the cell stacking direction; a side plate disposed at the side of the cell stacking direction; both ends of the side plate are provided with extensions perpendicular to themselves; the extensions form a partial enclosure on the outer edge of the end plate; the extensions and the end plate are detachably connected by fasteners; the two together form a rigid protective frame surrounding all the cells; and the cells are provided with fire-extinguishing armor at the welding point of the tabs; the fire-extinguishing armor is a rubber layer structure embedded with fire-extinguishing beads.

[0007] Preferably, the end plate includes protrusions protruding outward from both sides, and an extension correspondingly surrounds the outer side of the protrusion, with the inner side of the extension parallel and fitting to the outer side of the protrusion.

[0008] Preferably, an epoxy board and a thick EVA foam are sequentially arranged on the inner side of the end plate facing the cell. The two are pressed onto the end face of the cell synchronously with the end plate to achieve end insulation and expansion buffering functions.

[0009] Preferably, a side epoxy plate is provided on the inner side of the side plate facing the cell, which is pressed against the side edge of the cell along with the side plate to achieve the functions of side insulation and sealing edge support.

[0010] Preferably, the electrode stacking direction of the battery cell is consistent with the first stacking direction, and the side sealing edge of the battery cell is arranged facing the inside of the side plate to avoid squeezing contact with the end plate.

[0011] Preferably, a top support plate is provided above the stacked battery cells. The top support plate is located between the end plates at both ends, with its two ends fixed to the end plates and its bottom adapted to the upper surface of the battery cells.

[0012] Preferably, the upper surface of the top support plate is provided with a fire extinguishing component, including: a bottom adhesive layer, fire extinguishing beads embedded in the adhesive layer, and an upper thin EVA board. When the battery cell overheats, the fire extinguishing beads can automatically rupture to release the fire extinguishing medium.

[0013] Preferably, the extension portion has a ball head on the inner side facing the end plate, and the end plate has a vertically extending groove at the corresponding position, the groove including: The vertical section has an opening at its upper end that extends through the upper surface of the end plate; The inclined section connects to the lower end of the vertical section at its upper end, and its lower end has a groove bottom that bends toward the center of the battery cell.

[0014] Preferably, the opening edge is set as an inlet fillet, and the ball head can be inserted into the groove along the opening to achieve vertical guiding assembly.

[0015] Preferably, the bottom of the groove is provided with a locking recess that matches the size of the ball head. When the ball head slides to the bottom of the groove, it can be locked into the locking recess to achieve temporary locking during the assembly process.

[0016] Compared to existing technologies, this invention offers the following advantages: The side plate utilizes a vertical insertion design combined with a ball-head sliding groove guide structure, eliminating the need for additional positioning fixtures. The insertion process prevents misalignment of stacked cells, significantly improving assembly efficiency and yield. The ball head automatically engages with the locking recess after sliding into the groove, providing temporary fixation. A clicking sound indicates proper assembly, eliminating the need for individual torque checks and significantly reducing labor costs. The inclined sliding groove and buffer foam work in tandem, automatically compensating for clamping force during cell expansion, preventing stress concentration damage to the electrode sheets and extending cell cycle life. Double insulation layers eliminate the risk of short circuits and edge damage, while built-in fire extinguishing beads and overpressure relief structures greatly enhance safety. The modular, detachable structure allows for individual replacement in case of damage, resulting in low maintenance costs. Multiple configurations are compatible without requiring repeated mold opening, and the flexible cantilever adapts to machining tolerances, further reducing manufacturing costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a soft-pack battery module for an electric bicycle. Figure 2 An exploded view of the structure of a soft-pack battery module for an electric bicycle. Figure 3 This is a schematic diagram showing the positional relationship between the end plate and the front epoxy board. Figure 4 This is a schematic diagram showing the positional relationship between the side panel and the side epoxy board; Figure 5 This is a schematic diagram of the fire extinguishing assembly structure; Figure 6 A schematic diagram of the end plate and its groove structure; Figure 7 for Figure 6 Enlarged view of region A in the middle; Figure 8 This is a schematic diagram showing the positional relationship between the extension and the ball head; Figure 9 This is a schematic diagram showing the assembly direction of the extension plate and the end plate; Figure 10 This is a schematic diagram showing the relationship between the unloading notch and the ball head position; Figure 11 for Figure 10 Enlarged view of region B in the middle; Figure 12 This is a schematic diagram of the overall structure of the battery module according to Embodiment 2 of the present invention; Figure 13 This is an exploded view of the battery module structure according to Embodiment 2 of the invention.

[0018] Reference numerals: 1. Battery cell; 11. Bolt; 2. End plate; 21. Protrusion; 3. Side plate; 31. Extension; 41. Front epoxy board; 42. Side epoxy board; 5. Thick EVA foam; 6. Top support plate; 61. Bracket; 62. Protective plate; 7. Fire extinguishing assembly; 71. Adhesive layer; 72. Fire extinguishing bead; 73. Thin EVA board; 8. Ball head; 81. Unloading notch; 9. Slide groove; 91. Vertical section; 92. Inclined section; 93. Locking recess. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] See Figure 1 An electric bicycle soft-pack battery module structure includes: a plurality of soft-pack cells 1 arranged along a first stacking direction, an end plate 2 disposed at the end of the cell 1 in the stacking direction, a side plate 3 disposed on the side of the cell 1 in the stacking direction, the two ends of the side plate 3 are provided with extensions 31 perpendicular to themselves, the extensions 31 form a partial enclosure on the outer edge of the end plate 2, the extensions 31 and the end plate 2 are detachably connected by fasteners, and the two enclose to form a rigid protective frame that surrounds all the cells 1.

[0021] In this design, the first stacking direction is the thickness direction of the soft-pack battery cell 1. The end plate 2 is parallel to the outer side of the two end faces formed after the battery cells 1 are stacked, and the plate surface is completely aligned with the end face of the battery cell 1. The side plate 3 is parallel to the outer side of the two side faces formed after the battery cells 1 are stacked, and the plate surface is completely aligned with the side face of the battery cell 1. The extensions 31 at both ends of the side plate 3 are sheet-like structures formed by bending perpendicularly from the short edge of the side plate 3 towards the end plate 2 at a bending angle of 90 degrees. The extensions 31 are just fastened to the outer side of the left and right edges of the end plate 2, and the coverage area covers the entire assembly area of ​​the edge of the end plate 2. The extensions 31 and the end plate 2 have coaxial threaded holes at corresponding positions. The fasteners are M4 high-strength bolts 11. After the bolts 11 are tightened through the holes, the inner contour of the frame formed by the end plate 2 and the side plate 3 is completely matched with the outer contour of the stacked battery cells 1. All battery cells 1 are wrapped inside the frame without being exposed. The tightening direction of the bolts 11 is perpendicular to the direction of the tensile force of the expansion of the battery cells 1 on the side plate 3, which can reduce the risk of the side plate being torn by force.

[0022] During assembly, this structure only requires stacking the battery cells 1, then fastening the end plate 2 and side plate 3, and finally aligning the connecting holes and tightening the bolts 11 to complete the frame assembly. No additional positioning tooling is needed, which significantly improves the alignment accuracy and assembly efficiency. The unified frame reference also provides a stable installation foundation for the subsequent ball head 8 and sliding groove 9 structures, ensuring the accuracy of the sliding fit. The expansion force generated by the battery cells 1 during use will be evenly borne by the rigid frame, preventing local bulging and frame deformation caused by stress dissipation. If the side plate 3 or end plate 2 is damaged later, the corresponding component can be replaced by unscrewing the bolts 11 without disassembling the battery cell stack structure, which significantly reduces maintenance costs.

[0023] The end plate 2 is made of 2mm thick sheet metal through stamping. The protrusions 21 on both sides are press-fitted edges, which can increase the effective depth of the threaded holes. The end plate 2 has vertically extending reinforcing ribs stamped in the middle of the plate surface, which increases rigidity by more than 30% and can forcibly suppress the "bulging" deformation of the battery cell 1, avoiding outward bulging that could cause the housing to fail to fit. The extension 31 surrounds the outside of the protrusion 21, and the inner side of the extension 31 is parallel and fits against the outer side of the protrusion 21. The protrusions 21 on both sides of the end plate 2 are integral stamped flanges that extend vertically along the left and right edges of the end plate 2. The flanges protrude in a direction away from the battery cell 1. The height of the protrusions 21 is completely consistent with the thickness of the extension 31. When the extension 31 is fastened to the outside of the protrusions 21, the inner side of the extension 31 is completely parallel and fits against the outer side of the protrusions 21 without any local gaps. The threaded holes on the extension 31 and the protrusions 21 are staggered vertically, with at least two sets, to ensure uniform force after connection. The slide groove 9 is directly opened on the protrusions 21, and the two are an integral structure.

[0024] This structure solves the problems of existing end plate 2 being a planar structure, lacking a positioning reference when connecting side plates 3 requiring repeated alignment adjustments, resulting in low assembly efficiency, easy warping and deformation of the edge of end plate 2 after cell 1 expands, and poor connection reliability. During assembly, the extension 31 automatically completes initial positioning as long as it is snapped onto the protrusion 21, eliminating the need for repeated alignment adjustments and significantly improving assembly efficiency. The flanged structure enhances the deformation resistance of the edge of end plate 2, preventing warping of the protrusion 21 when cell 1 expands. This ensures stable position accuracy of the groove 9 on the protrusion 21 and prevents the ball head 8 from getting stuck. During disassembly, because it is a surface-fit connection, there is no local scratching deformation, and the disassembled end plate 2 and side plate 3 can be reused.

[0025] See Figures 2-3An epoxy board 41 and a thick EVA foam 5 are sequentially arranged on the inner side of the end plate 2 facing the battery cell 1. The two are pressed onto the end face of the battery cell 1 simultaneously with the end plate 2 to achieve end insulation and expansion buffering functions. The epoxy board 41 is completely laid flat on the inner surface of the end plate 2 facing the battery cell 1, and its shape is completely consistent with the inner contour of the end plate 2, with its four edges flush with the edge of the end plate 2. The thick EVA foam 5 is completely attached to the side surface of the epoxy board 41 facing the battery cell 1, and its shape is completely consistent with the epoxy board 41, with its edges aligned with the edge of the epoxy board. The epoxy board 41 and the thick EVA foam 5 are pre-bonded to the inner side of the end plate 2 with double-sided adhesive and are pressed onto the end face of the battery cell 1 simultaneously with the locking of the end plate 2.

[0026] During the cycling process, the expansion deformation of cell 1 is adaptively compressed and absorbed by the thick EVA foam 5, maintaining uniform stress on the end face of cell 1 and avoiding local stress concentration that could damage the electrode. This extends the cycle life of cell 1. The front epoxy plate 41 completely isolates the metal end plate 2 from cell 1, eliminating the risk of short circuits caused by contact between the electrode tab of cell 1 and the end plate 2. This structure can also be linked with the wedge-shaped groove 9 structure. When the end plate 2 expands and bends outward with cell 1, the inclined section 92 drives the side plate 3 to tighten inward, offsetting the permanent compression deformation of the EVA foam and maintaining the initial clamping force of cell 1. During assembly, the compression rate of the thick EVA foam 5 can be adjusted by controlling the pressure applied to the end plate 2 to achieve different threshold preload forces. Preload can be completed simply by tightening the bolt 11 under pressure. The operation is simple and requires no additional tooling. The force direction of bolt 11 is perpendicular to the expansion direction of cell 1, resulting in a better force structure that can resist the large expansion force generated by cell 1 for a long time.

[0027] See Figure 4A side epoxy plate 42 is provided on the inner side of the side plate 3 facing the cell 1. It is pressed against the side edge of the cell 1 along with the side plate 3, realizing the functions of side insulation and sealing edge support. The side epoxy plate 42 is completely laid flat on the inner surface of the side plate 3 facing the cell 1, and its shape is completely consistent with the inner contour of the side plate 3. Its upper and lower edges are flush with the edge of the side plate 3. The thickness of the side epoxy plate 42 just fills the assembly gap between the side plate 3 and the side sealing edge of the cell 1. After the side plate 3 is locked, the side epoxy plate 42 is only pressed against the sealing edge area of ​​the cell 1 without active material, and will not come into contact with the main body of the cell 1 containing the electrode sheets. The side epoxy plate 42 can be pre-bonded to the inside of the side plate 3, eliminating the need for additional placement during assembly and simplifying the process. When the cell 1 expands, the edge sealing is rigidly supported by the side epoxy plate 42, preventing bending and breakage. Simultaneously, it does not compress the internal electrodes of the cell 1, thus not affecting its performance. The side epoxy plate 42 and the insulating coating on the side plate 3 form double insulation protection. Even if one layer is damaged, the reliability of the side insulation is still guaranteed, preventing short circuits caused by leakage from the edge sealing. This module's structural components occupy minimal space; the total thickness of the end plate 2 on one side is only 4mm, and the side plate 3 only includes the thickness of the side plate 3 and the side epoxy plate 42, with a total thickness of less than 2mm on one side. Under the same external dimensions, the capacity of the cell 1 is increased by more than 10%, and the space utilization is significantly better than module structures with plastic supports.

[0028] The electrode stacking direction of cell 1 is consistent with the first stacking direction. The side sealing edges of cell 1 are arranged facing the inner side of side plate 3 to avoid squeezing contact with end plate 2. The electrode sheets of the soft-pack cell 1 are stacked along the thickness direction of cell 1 and completely coincide with the first stacking direction. The two side sealing edges of cell 1 are sheet-like structures formed by hot pressing aluminum-plastic film, without any electrode sheets or active materials. When stacking cell 1, all sealing edges face the side plates 3 on the left and right sides, and do not face the end plates 2 at the front and rear ends. When the end plates 2 are locked, they will not contact the sealing edges. This invention solves the problems of inconsistent sealing edge orientation of existing cells 1, with some facing the end plate 2, which requires repeated adjustments during stacking and the end plate 2 easily squeezing the sealing edge and causing damage during expansion. When stacking cells 1, there is no need to repeatedly adjust the sealing edge orientation; it is sufficient to uniformly face the side, resulting in higher stacking efficiency. When cells 1 expand and bulge, the sealing edge facing the side plate 3 will not be squeezed and damaged by the end plate 2, reducing the risk of leakage. In the later stage, when checking whether the sealing edge is damaged, it can be visually inspected directly from the side of the module without disassembling the cell 1 stacking structure.

[0029] See Figure 5A top support plate 6 is installed above the stacked battery cells 1. The top support plate 6 is located between the end plates 2 at both ends, with its two ends fixed to the end plates 2 and its bottom adapted to the upper surface of the battery cells 1. The top support plate 6 is horizontally covered on the upper surface of all the stacked battery cells 1, with its left and right ends resting precisely on the mounting platforms reserved on the top of the end plates 2 at both ends, and is fixed to the end plates 2 by clips or screws; the bottom of the top support plate 6 is completely flush with the upper surface of the battery cells 1, with no suspended areas; two structures can be selected according to usage requirements: the first is an integrated board made of pure insulating material, used only to support the upper components; the second is a PCB adapter board with integrated sampling circuitry, which can simultaneously realize the voltage and temperature sampling functions of the battery cells 1. When different functional configurations are required, only the corresponding type of top support plate 6 needs to be replaced. No other structure of the module needs to be modified, making it more adaptable. During assembly, the positioning boss can be inserted into the groove to complete the alignment without adjustment, making the assembly speed faster. The top support plate 6 completely covers the upper surface of the battery cell 1, which can prevent external bumps from damaging the battery cell 1. This structure also provides an installation benchmark for the subsequent fire extinguishing component 7. The support plate has a pre-cut groove, and the fire extinguishing component 7 will not shift when embedded in the groove. During later maintenance, only the fixing parts at both ends need to be removed to replace the top support plate 6, without modifying the stacking structure of the battery cell 1.

[0030] A fire extinguishing assembly 7 is provided on the upper surface of the top support plate 6, including: a bottom adhesive layer 71, fire extinguishing beads 72 embedded in the bottom adhesive layer 71, and an upper thin EVA board 73. When the battery cell 1 overheats, the fire extinguishing beads 72 can automatically rupture to release the fire extinguishing medium. The fire extinguishing assembly 7 completely covers the upper surface of the top support plate 6. The adhesive layer 71 is uniformly coated in the preset installation area of ​​the top support plate 6. The fire extinguishing beads 72 are inert medium particles encapsulated in microcapsules, uniformly dispersed and embedded inside the adhesive layer 71, and are bonded and fixed by the adhesive layer 71 without displacement. The upper thin EVA board 73 covers the outside of the adhesive layer 71 and the fire extinguishing beads 72 and is bonded to the adhesive layer 71 as a whole. The rupture temperature of the microcapsule shell outside the fire extinguishing beads 72 matches the thermal runaway warning temperature of the battery cell 1. During assembly, the fire extinguishing component 7 can be prefabricated into an integrated diaphragm and directly attached to the top support plate 6, eliminating the need to place the fire extinguishing beads 72 one by one, thus improving assembly efficiency. When the battery cell 1 overheats abnormally, the microcapsule shell automatically ruptures, and the fire extinguishing medium is released and can quickly fill the gaps inside the module, suppressing heat diffusion and greatly improving safety under extreme conditions. The fire extinguishing medium is an inert insulating material that will not corrode the internal components of the module. Cell 1 features a fire-extinguishing armor at the electrode tab welding point. This armor is a layered adhesive structure embedded with fire-extinguishing beads. Specifically, a 1.5mm thick thermally conductive semi-self-leveling high-viscosity adhesive is applied to the surface of the electrode tab welding point. Before the adhesive initially cures, 1mm diameter fire-extinguishing beads 72 are sprinkled onto the surface. The fire-extinguishing beads 72 are partially embedded inside the adhesive layer 71, and the upper layer is covered with 0.5mm thick protective foam, with an overall thickness not exceeding 2.5mm. This structure protects the electrode tab welding point from impact failure. Furthermore, since the electrode tab is the first point of thermal runaway, it can trigger the rapid rupture of the fire-extinguishing beads 72 to release the fire-extinguishing medium. The response speed is 60% faster than the top fire-extinguishing component 7, which can suppress the fire in the early stages of thermal runaway, providing users with escape time. This design is extremely low-cost and occupies very little space, making it suitable for the cost and space requirements of two-wheeled vehicle batteries.

[0031] See Figures 6-8 The extension 31 has a ball head 8 on its inner side facing the end plate 2, and the end plate 2 has a vertically extending groove 9 at the corresponding position. The groove 9 includes: The vertical section 91 has an opening at its upper end that extends through the upper surface of the end plate 2; The inclined section 92 is connected at its upper end to the lower end of the vertical section 91, and its lower end is provided with a groove bottom and bends toward the center of the battery cell 1.

[0032] The ball head 8 is a hemispherical structure protruding outward from the side surface of the extension 31 facing the protrusion 21 of the end plate 2, and is integrally stamped with the extension 31; the groove 9 is a blind groove opened on the protrusion 21 of the end plate 2, extending vertically along the protrusion 21, the upper half is a vertical section 91, the upper end of which penetrates the top surface of the protrusion 21 to form an opening, the lower half is an inclined section 92, which bends towards the direction of the battery cell 1, and the bottom end is an arc-shaped closed groove bottom that matches the curvature of the ball head 8; the diameter of the ball head 8 is slightly smaller than the width of the groove 9, so that it can slide smoothly in the groove 9 without jamming.

[0033] This structure solves the problems of existing side plate 3 assembly, which requires lateral insertion, easily pushes the stacked battery cells 1 out of place, requires tooling for positioning, has low assembly efficiency, and the clamping force of battery cells 1 decreases rapidly after expansion, requiring additional compensation structures. When assembling side plate 3, the ball head 8 is aligned with the upper opening of the slide groove 9 and slids downward. After sliding into the inclined section 92, it will automatically drive side plate 3 to tighten towards battery cells 1. There is no need to manually apply lateral pushing force, and it will not push the stacked battery cells 1 out of place. The assembly qualification rate can reach 100%. When battery cells 1 bulge after long-term use, end plate 2 will produce outward bending deformation. As the inclined section 92 moves outward with end plate 2, it will drive side plate 3 to tighten inward, which will offset the permanent compression deformation of the internal thick EVA foam 5 and always keep the clamping force of battery cells 1 within a reasonable range. When disassembling side plate 3, it is only necessary to pull upward, and the ball head 8 can slide out along the slide groove 9. It is not necessary to completely unscrew all bolts 11, which greatly improves disassembly efficiency.

[0034] The opening edge is designed with rounded corners for insertion, allowing the ball head 8 to be inserted into the slide groove 9 for vertical guiding assembly. The opening area has a flared structure that is wider at the top and narrower at the bottom, with the maximum width of the flared opening greater than the diameter of the ball head 8, significantly improving the alignment tolerance. Even novice workers can slide the ball head 8 into the slide groove 9 without precise alignment. When the ball head 8 slides to the bottom of the slide groove 9, the threaded hole on the extension 31 is perfectly aligned with the threaded hole on the protrusion 21 of the end plate 2, allowing the bolt 11 to be inserted directly without additional alignment adjustments. The rounded corners of the opening have no sharp edges, preventing scratches on the surface of the ball head 8 during sliding and preventing jamming issues even after long-term use. The bottom of the slide groove 9 has a locking recess 93 that matches the size of the ball head 8, allowing the ball head 8 to be temporarily locked when it slides to the bottom of the groove. The locking recess 93 is a hemispherical structure recessed from the bottom of the groove 9 towards the outside of the protrusion 21. Its diameter matches the diameter of the ball head 8, and its depth is just enough to accommodate part of the volume of the ball head 8. The edge of the recess is rounded and has no step structure. The threshold of the disengagement thrust after the ball head 8 is inserted into the locking recess 93 is slightly greater than the maximum expansion thrust of the battery cell 1 during normal cycle and less than the axial tension when the bolt 11 is loosened.

[0035] This structure solves the problems of existing assembly methods, such as the lack of a temporary locking mechanism for side plate 3, the need for manual support to prevent slippage, the inefficiency of individually checking the torque of bolts 11, and the lack of a pressure relief mechanism when battery cell 1 expands abnormally, which could easily crack the frame and cause safety hazards. When ball head 8 slides to the bottom of the groove, it automatically engages with the locking recess 93, preventing side plate 3 from shifting. Installing bolts 11 does not require manual support of side plate 3; it can be operated by a single person. A clear sound is emitted when the bolts are engaged, serving as a criterion for proper assembly. It eliminates the need to check each bolt 11 individually. The torque significantly reduces quality inspection costs. During normal cyclic expansion, the thrust is less than the disengagement threshold, keeping the lock in place. When the battery cell 1 expands abnormally and the thrust exceeds the threshold, the ball head 8 will automatically disengage from the locking recess 93 to release pressure, preventing the rigid frame from cracking and significantly improving the safety level. This structure can also be linked with the unloading notch 81 structure. When it is engaged or disengaged, the elastic cantilever deforms slightly, preventing jamming or breakage. When disassembling, loosen the bolt 11 and pull upwards, and the ball head 8 will automatically disengage from the locking recess 93 without the need for additional prying parts.

[0036] See Figure 9 Each extension 31 has a single ball head 8 at its very bottom on the inner side facing the end plate 2. After all the bolts 11 are unscrewed, the ball head 8 and the spherical surface of the locking recess 93 cooperate to form a rotating pair. The side plate 3 can swing open around this rotating pair in a direction away from the battery cell 1 without completely disengaging from the slide groove 9. A single ball head 8 is provided only at the bottom inner side of each extension 31 facing the end plate 2. The bottom of the groove 9 is provided with a hemispherical locking recess 93 only corresponding to the position of the ball head 8. When the bolts 11 are fully tightened, the inner side of the extension 31 is completely pressed against the outer side of the protrusion 21 of the end plate 2. The fit between the ball head 8 and the locking recess 93 is rigidly locked with no relative movement. After all the bolts 11 are unscrewed, the surface contact constraint between the extension 31 and the protrusion 21 is released. The spherical fit naturally forms a rotating pair. The side plate 3 can swing and open around the fulcrum in a direction away from the battery cell 1 without coming out of the groove 9. Pulling it upwards will allow the ball head 8 to slide out along the groove 9 to achieve complete disassembly.

[0037] This structure solves the problems of existing side plates 3 requiring complete removal to access the side of the battery cell 1 during maintenance, resulting in long maintenance time and low maintenance efficiency after disassembly and re-alignment. When routinely checking the edge sealing of the battery cell 1 or replacing the aging side epoxy plate 42, only the bolt 11 needs to be unscrewed to swing the side plate 3 outwards and open it, without having to completely remove the side plate 3. The side plate 3 will not fall off or be lost during the operation, which can quickly free up sufficient operating space and significantly shorten maintenance time. If it is necessary to completely replace the side plate 3 or deeply disassemble the module, the side plate 3 can be quickly removed by pulling it upwards. It takes into account the needs of two maintenance scenarios. In the assembled and locked state, the original functions such as the overall rigidity of the frame, expansion self-adaptive compensation, and overpressure relief are not affected in any way, and the structural reliability is completely consistent with the original solution.

[0038] See Figures 10-11 The ball head 8 has a semi-open stress-relieving notch 81 around its root, forming a slightly floating elastic cantilever structure in the area where the ball head 8 is located, which is adapted to the machining tolerance of the slide groove 9. The stress-relieving notch 81 is a semi-open notch formed by stamping around the root of the ball head 8. The notch is set around the root of the ball head 8, so that the extension 31 area where the ball head 8 is located is connected to the main body on only one side, forming a slightly displaceable elastic cantilever structure; the maximum floating amount of the cantilever can just offset the conventional machining tolerance of the slide groove 9 and the ball head 8. This structure solves the problems of jamming, excessive clearance causing wobble, and high cost associated with high machining precision when there are tolerances in the machining of the slide groove 9 and ball head 8. Machining the slide groove 9 and ball head 8 does not require excessively high precision; slight dimensional and positional deviations can be accommodated by the floating cantilever, reducing machining costs and part defect rates. Even with minor deviations in the slide groove 9 or ball head 8 during assembly, it can still slide smoothly without jamming, providing a uniform assembly feel. When the battery cell 1 expands and is subjected to force, the cantilever can generate a small deformation to relieve the force, preventing breakage of the ball head 8 or slide groove 9, thus improving structural reliability. The thin EVA board 73 serves as a flexible buffer layer, completely covering all areas of the adhesive layer 71 and the extinguishing beads 72, achieving physical encapsulation and protection of the extinguishing medium. Exposed extinguishing beads 72 are prone to detachment during transportation and use, resulting in rapid wear and tear and reduced extinguishing effectiveness. The covering structure of the thin EVA board 73 prevents the extinguishing beads 72 from being shaken or knocked off during transportation or use, ensuring a service life consistent with the module. The thin EVA itself is flame-retardant and will not become a source of combustion. When the battery cell 1 overheats, the EVA will automatically melt, without hindering the release of the extinguishing medium or affecting the extinguishing effect.

[0039] Example 2: See Figures 12-13Based on Embodiment 1 of the present invention, a bracket 61 can be selectively installed above the top support plate 6. A protective plate 62 is fixed on the bracket 61, and the protective plate 62 is electrically connected to the tab of the battery cell 1 to realize the status monitoring and charge / discharge control of the battery cell 1. The bottom of the bracket 61 is provided with positioning protrusions, which engage with the preset grooves on the top of the end plate 2 to achieve initial positioning. Only one fixing bolt 11 needs to be set on one side of the bracket 61 to complete the locking, avoiding the over-positioning problem caused by double bolts 11. When the battery cell 1 expands, the rear end plate 2 moves slightly outward, which can automatically clamp the bottom of the bracket 61 without the need to add additional fixing points, resulting in strong structural stability. When the top support plate 6 is selected to use a PCB adapter board with integrated sampling circuitry, the bracket 61 is installed and fixed on the upper end face of the top support plate 6, or it can be fixed on the top of the end plates 2 at both ends. The protective plate 62 is fixed to the bracket 61 with screws and electrically connected to the tab of the battery cell 1 or the sampling circuitry of the top support plate 6 via a flexible ribbon cable. When the battery management function is not required, the bracket 61 and the protective plate 62 can be directly omitted without affecting the normal use of other structures in the module. The aforementioned replaceable structure solves the problems of existing module BMS being an integrated design, incurring additional costs even in scenarios where BMS is not needed, and high repair costs when BMS is damaged, requiring replacement of the entire module. The protection board 62 can be flexibly selected based on product positioning, adapting to electric bicycle products with different price points and functional requirements. It does not require modification of the main module structure, and when the protection board 62 fails later, it can be disassembled and replaced separately without disassembling the battery cell stack structure or discarding the entire module, significantly reducing maintenance costs.

[0040] This module adopts a universal framework design, and only the length of the side plate 3 needs to be adjusted when adapting to different voltage platforms, which can reduce the serialization development cost by more than 70%. When using the adapter board + protection board 62 solution, only the length of the bracket 61 needs to be adjusted synchronously to complete the adaptation, which greatly shortens the development cycle.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An electric bicycle pouch cell module structure, comprising: A plurality of battery cells (1) are arranged along the first stacking direction. An end plate (2) is provided at the end of the battery cell (1) in the stacking direction. A side plate (3) is provided on the side of the battery cell (1) in the stacking direction. The two ends of the side plate (3) are provided with extensions (31) perpendicular to itself. The extensions (31) form a partial enclosure on the outer edge of the end plate (2). The extensions (31) and the end plate (2) are detachably connected by fasteners. The two enclose each other to form a rigid protective frame that surrounds all the battery cells (1). The battery cell (1) is provided with a fire extinguishing armor at the welding point of the electrode tab. The fire extinguishing armor is a rubber layer structure embedded with fire extinguishing beads (72).

2. The soft pack battery module structure for an electric bicycle according to claim 1, characterized in that: The end plate (2) includes protrusions (21) protruding outward from both sides, and the extension (31) is correspondingly surrounded on the outside of the protrusions (21), with the inner side of the extension (31) and the outer side of the protrusions (21) being parallel and fitted.

3. The soft pack battery module structure for an electric bicycle of claim 1, wherein The end plate (2) is provided with a front epoxy plate (41) and a thick EVA foam (5) on the inner side facing the cell (1). The two are pressed onto the end face of the cell (1) synchronously with the end plate (2) to achieve end insulation and expansion buffering functions.

4. The soft pack battery module structure for an electric bicycle of claim 1, wherein, The side plate (3) is provided with a side epoxy plate (42) facing the inside of the cell (1), which is pressed against the side edge of the cell (1) along with the side plate (3) to achieve the functions of side insulation and sealing edge support.

5. The soft pack battery module structure for an electric bicycle of claim 1, wherein The electrode stacking direction of the battery cell (1) is consistent with the first stacking direction, and the side sealing edge of the battery cell (1) is arranged towards the inside of the side plate (3) to avoid squeezing contact with the end plate (2).

6. The soft pack battery module structure for an electric bicycle of claim 1, wherein, A top support plate (6) is provided above the stacked battery cell (1). The top support plate is located between the end plates (2) at both ends. Its two ends are fixed to the end plates (2), and its bottom is adapted to connect with the upper surface of the battery cell (1).

7. The electric bicycle pouch cell module structure of claim 6, wherein, The top support plate (6) is provided with a fire extinguishing component (7), including: a bottom adhesive layer (71), a fire extinguishing bead (72) embedded in the adhesive layer (71), and an upper thin EVA plate (73). When the battery cell (1) overheats, the fire extinguishing bead (72) can automatically break and release the fire extinguishing medium.

8. The electric bicycle pouch cell module structure of claim 1, wherein, The extension (31) has a ball head (8) on its inner side facing the end plate (2), and the end plate (2) has a vertically extending groove (9) at the corresponding position. The groove (9) includes: The vertical section (91) has an opening at its upper end that penetrates the upper surface of the end plate (2); The inclined section (92) has its upper end connected to the lower end of the vertical section (91), and its lower end has a groove bottom and bends toward the center of the cell (1).

9. The electric bicycle pouch cell module structure of claim 8, wherein, The opening edge is set as an inlet rounded corner, and the ball head (8) can be inserted into the groove (9) along the opening to achieve vertical guiding assembly.

10. The electric bicycle pouch cell module structure of claim 8, wherein, The bottom of the groove (9) is provided with a locking recess (93) that matches the size of the ball head (8). When the ball head (8) slides to the bottom of the groove, it can be locked into the locking recess (93) to achieve temporary locking during the assembly process.

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