Capacity expansion design of sodium battery (lithium battery) electric bicycle battery pack

Abstract

The invention discloses a capacity expansion design of a sodium battery (lithium battery) electric bicycle battery pack, and belongs to the technical field of electric bicycle battery structures. The design comprises an annular glue pouring groove formed by a bottom shell and an upper cover, detachable silica gel is filled in the annular glue pouring groove to realize elastic sealing, and a waterproof and anti-loosening structure is formed by matching with bolt fixation. The module assembly adopts a soft package battery cell array, and a pre-pressing gap is formed between the top supporting pad and the upper cover to limit the vertical displacement of the module. The upper cover integrated protection plate and the heat conduction silica gel pad form a heat dissipation channel and share a vertical space with the glue pouring groove to improve the utilization rate. Buffer foam is arranged between the battery cells, and a heat conduction film is attached to a tab to achieve effective soaking between the battery cells. The bottom shell is a flat and straight frame without other structures such as flanges, occupies a small space, and can be assembled and disassembled quickly by combining with a pressing rivet nut. Through compact layout and detachable sealing design, the capacity of the battery cells is remarkably improved in a limited space, heat uniformization, vibration resistance and maintenance convenience among the battery cells are considered, and the battery capacity expansion device is suitable for the battery capacity expansion requirement of the electric bicycle.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle battery structures, and particularly to an expansion design of a sodium (lithium) electric bicycle battery pack. Background Art

[0002] With the rapid development of new energy technologies, sodium-ion batteries and lithium-ion batteries have been widely used in the field of electric bicycles due to their advantages such as high energy density and long cycle life. However, restricted by vehicle design and existing frame molds, the external dimensions of electric bicycle battery packs are usually fixed. How to increase the capacity within a limited space while taking into account objectives such as safety, maintainability, and heat dissipation performance has become a difficult point for industry technology research.

[0003] Currently, the following technical bottlenecks exist in the design of electric bicycle battery packs: The traditional core arrangement method is restricted by the protection structure and sealing requirements, with insufficient space utilization and difficulty in achieving maximum capacity. The all-glue filling solution inside the housing brings disadvantages such as high glue cost, a relatively large increase in product weight, and difficulty in disassembly, while the reinforced sealing design will also occupy the core layout space. Secondly, the thickness expansion (usually 5%) generated by sodium / lithium cores during charge and discharge requires relying on the end plate and steel belt to apply the pre-tightening force inside the module, and fixing the module through long screws, relying on the large stiffness of the end plate to resist the core expansion and swelling problems. However, the traditional constraint structure occupies too much internal space, resulting in limited expansion. In addition, the existing battery pack shells mostly use epoxy resin potting for sealing, and it is difficult to disassemble them without damage after curing, resulting in high maintenance costs. In terms of thermal management, the heat dissipation path between the core and the protection board is single, and there is no heat equalization design between the cores, which is likely to affect the performance due to local temperature rise; while the protection boards are mostly installed independently, and the parallel layout occupies additional height space, further compressing the core layout space. At the same time, problems such as the shielding effect of the metal shell on wireless signals and the decrease in yield rate caused by complex assembly processes all restrict the reliability and practicality of high-capacity battery packs.

[0004] In existing improvement solutions, although individual designs attempt to optimize the space layout or heat equalization structure, the contradictions between expansion and protection, sealability and disassembly, thermal management, and assembly efficiency have not been systematically resolved. For example, the disclosed technology CN208655743U discloses a soft-pack core battery pack, but there is still room for improvement in the optimization of the battery pack structure. Therefore, it is necessary to study an expansion design solution for a battery pack that takes into account high energy density, reliable sealing, maintainability, and efficient heat equalization to meet the core requirements of electric bicycles for lightweight, long endurance, and low-cost maintenance. Summary of the Invention

[0005] The present invention aims to provide a capacity expansion design scheme for a sodium (lithium) electric bicycle battery pack, which solves the problem of vertical space waste caused by redundant sealing structure, thick expansion suppression components and dispersed heat dissipation / circuit layout in traditional battery packs through the coordinated optimization of annular glue filling grooves, soft-pack battery cell array constraint structure and space reuse technology.

[0006] A capacity expansion design for a sodium (lithium) electric bicycle battery pack includes a bottom shell, a module assembly is placed inside the bottom shell, an upper cover is installed on the top of the bottom shell, the top edge of the bottom shell and the bottom edge of the upper cover together form an annular glue pouring groove, the annular glue pouring groove is filled with detachable potting silicone, the module assembly includes a soft-pack battery cell array, the battery cell side is fastened with an end plate, and a support pad is installed above the end plate. The bottom shell adopts a flat sheet metal shell, which effectively protects the internal module assembly while occupying a relatively small size. The annular structure of the annular glue pouring groove eliminates the joint weakness of traditional linear glue pouring, and with the elastic deformation ability of silicone, it still maintains a complete seal under vehicle vibration conditions. The annular glue pouring groove and the protective plate integrated with the upper cover share the vertical space, which effectively improves the space utilization rate of the battery pack and is very conducive to the expansion of the battery pack. After the detachable potting silicone is cured, a flexible adhesive layer is formed. When disassembling, the potting silicone can be directly disassembled to non-destructively separate the upper cover, so that the bolts can be reused. Compared with the traditional epoxy resin potting disassembly, the damage rate is greatly reduced. The internal module assembly is a soft-pack cell array, which fully utilizes the cells in the horizontal direction of the battery pack and allows multiple components to share space in the vertical direction, which can greatly improve space utilization. The end plate applies a pre-tightening force to the cells to suppress the expansion and deformation of the cells during charging and discharging. After the support pad is bonded and fixed to the end plate, a pre-compression gap will be formed between its top and the inner surface of the upper cover to restrain the vertical movement of the module assembly during product use. Compared with the traditional long screw constraint structure, the thickness of the end plate of the support pad can be designed to be very thin without being affected by the size of the long screw, the size of the bottom rivet nut, and the reserved assembly gap. Only the stiffness of the end plate itself needs to be considered, which greatly reduces the overall size of the battery pack.

[0007] A capacity expansion design for a sodium (lithium) electric bicycle battery pack, the support pad is made of an insulating elastic material, fixed between the end plate and the upper cover by bonding, to ensure that there is no gap in the vertical support after installation. The support pad is made of an insulating material and is used to block the direct contact between the end plate and the upper cover. Both the end plate and the upper cover are made of metal. The support pad can avoid the risk of short circuit caused by metal contact, especially when the battery cell is damp or condensed water intrudes, the insulation performance remains stable.

[0008] A capacity expansion design for a sodium (lithium) electric bicycle battery pack, with a protective plate and a thermally conductive silicone pad inside the upper cover. The protective plate is inverted on the inner surface of the upper cover to form a heat dissipation channel with the thermally conductive silicone pad. The protective plate is connected to the circuit module in the upper cover through a wiring harness. The protective plate is inverted on the inner surface of the upper cover and connected to the battery module, and the voltage, current and temperature parameters can be monitored in real time. When overcharging, overdischarging or short circuit abnormalities are detected, the circuit module can be cut off to prevent thermal runaway. The inverted design of the protective plate makes its metal substrate aluminum substrate fit tightly with the thermally conductive silicone pad to form a heat dissipation path. Heat can be transferred to the metal shell of the upper cover by natural convection through the protective plate. The protective plate and the annular glue filling groove share the vertical height space, avoiding the space waste caused by the traditional parallel layout, and providing additional thickness space for battery cell expansion.

[0009] A capacity expansion design for a sodium (lithium) electric bicycle battery pack. The module assembly has a tab on the top, and a graphene heat spreader is attached to the tab. The thickness of the graphene heat spreader is between 0.8mm and 1.2mm, and it occupies very little height space, which is convenient for battery cell expansion. The heat spreader is used to eliminate the temperature difference between battery cells and reduce the risk of low single cell voltage in the battery cell. The flexible properties of the graphene heat spreader allow the steel belt to apply preload without affecting the integrity of the thermal interface, and simultaneously achieve mechanical constraint and thermal management optimization. There is also an insulating layer between the graphene heat spreader and the upper cover to ensure the insulation of the battery cell and the upper cover.

[0010] A capacity expansion design for a sodium (lithium) electric bicycle battery pack, wherein an annular glue potting groove shares a height space with a protection plate, a bottom shell and an upper cover are fixed by bolts, and the detachable potting silicone is a modified two-component silicone or silicone gel, the detachable potting silicone covers the entire bolt, and effective sealing of the shell is achieved by sharing a height space with the protection plate, and the shell does not need to have flange edges or other space-occupying structures to ensure sealing performance.

[0011] The annular glue pouring groove and the protective plate integrated with the upper cover share the vertical space, which effectively improves the space utilization of the battery pack and is very beneficial to the expansion of the battery pack. The installation surface of the sheet metal upper cover and the bottom shell is realized by glue pouring, which is simple to operate and has excellent sealing effect. It is very suitable for mass production. Modified two-component silicone or silicone gel is a common glue on the market. It has both low cost and price advantages, which is conducive to product cost reduction and improves product competitiveness. The bottom shell and the upper cover are connected by bolts. The bolts are wrapped with glue, which solves the waterproof and airtightness problems of the bolts. The removable potting silicone wrapped bolts effectively prevent loosening.

[0012] An expansion design for a sodium (lithium) electric bicycle battery pack. There is buffer foam between the battery cells. A transfer board is welded to the top of the battery cells, and an epoxy board is pasted on the side of the battery cells. A steel strip is fastened outside the epoxy board and the end plate. The thickness of the end plate is between 5 mm and 7 mm, which is only half of the thickness of the conventional end plate, so as to reduce the internal size occupation and increase the thickness of the battery cells to achieve the expansion goal. The buffer foam provides a buffer space for the expansion of the battery cells, preventing the battery cells from expanding and squeezing each other and being damaged. The transfer board realizes the connection of the battery cells. Pasting the epoxy board on the side insulates from the bottom case. Installing the end plate and the steel strip realizes the restraint of the expansion of the battery cells. Applying a pre-tightening force to the battery cells when installing the steel strip is beneficial to improving the cycle life of the battery cells and the overall stiffness of the module components, and reducing the risk of misalignment between single battery cells.

[0013] An expansion design for a sodium (lithium) electric bicycle battery pack. The bottom case is a vertical rectangular structure, and reinforcing ribs are provided on the side walls. The bottom case is only the thickness of the sheet metal itself, without other additional structures such as conventional flange edges, greatly reducing the space occupation of the bottom case itself. The overall shape is coordinated. This type of outer shell can be used as a positioning reference, and there is no obstruction on the installation path of the components, facilitating internal assembly. The reinforcing ribs provided on the side walls can increase the overall stiffness of the side of the bottom case, and the added reinforcing ribs can be formed into different shapes to optimize the product appearance.

[0014] An expansion design for a sodium (lithium) electric bicycle battery pack. A rubber strip is provided on the surface of the annular potting groove, forming a sealing interface with the detachable potting silicone. The rubber strip can beautify the appearance of the battery pack and also ensure the integrity of the sealing interface, not being punctured by external sharp objects.

[0015] An expansion design for a sodium (lithium) electric bicycle battery pack. Rivet nuts are pre-installed on the inner side of the upper cover. The rivet nuts and bolts cooperate with each other to jointly fix the upper cover and the bottom case. The assembly and fastening method of the rivet nuts and bolts can reduce the assembly time and also ensure the uniformity of the bolt pre-tightening force, realizing the quick disassembly, assembly and repeated maintenance of the battery pack.

[0016] An expansion design for a sodium (lithium) electric bicycle battery pack. The upper cover is integrated with an antenna cover, and the antenna cover is connected to the circuit module in the upper cover through a wire harness. The antenna cover covers the communication window area of the upper cover, improving the transmission efficiency of wireless signals and solving the shielding effect of the metal shell on electromagnetic waves. The antenna cover is integrated in the non-expansion area of the upper cover, realizing the internal installation of the wireless module by using the original structural space of the battery pack and avoiding the installation position occupied by the external antenna. The wire harness is installed inside to avoid being damaged by external pulling. The wire harness uses a twisted shielded wire and is routed along the card slot preset on the inner wall of the upper cover to avoid communication interruption caused by electromagnetic interference inside the battery pack. The wire harness is reserved with an S-shaped bending section (the curvature radius is greater than 5 times the wire diameter) to absorb the micro-deformation of the shell when the battery pack is working and avoid the wire breaking caused by repeated stretching.

[0017] The advantages of the present invention are as follows: A soft-pack battery cell is used as the object. The size of the soft-pack battery cell can be adjusted flexibly, making good use of the space in the horizontal and vertical directions and improving the internal space utilization rate of the battery pack. A flat sheet metal shell is used as the battery pack housing. On the one hand, the sheet metal shell has strength and can effectively protect the internal battery cells; on the other hand, the thickness of the sheet metal itself is only at the millimeter level, occupying less space and facilitating the expansion of the battery pack. The scheme of using an upper cover and a bottom shell to form a potting groove realizes the effective sealing of the battery pack. The potting groove structure is a top annular structure, sharing the height dimension with the protection board, occupying less space and having reliable sealing. It avoids the conventional flange sealing structure of the housing, saves more dimensions, and is convenient for the expansion of the internal battery cells. The end plate and steel belt structure effectively restrain the expansion of the battery cells. Compared with the traditional long bolt restraint structure in the industry, the end plate here is only used as a support and is not restricted by the size of the long screw. Therefore, the end plate can be made very thin, minimizing the occupation of the dimension in the thickness direction of the battery cell. The top sealant of the battery pack adopts a potting silicone rubber solution. The silicone rubber is a detachable glue, facilitating the subsequent disassembly and maintenance of the housing. The designed module and the housing only reserve an assembly space in the horizontal direction, and a graphene heat spreader adhered to the housing is pasted at the battery tab. This heat spreader is only 1 mm thick and has high thermal conductivity, realizing the heat equalization of the battery cells in the battery pack. The protection board is inverted on the upper cover, and a thermal conductive silicone pad is adhered between the protection board and the upper cover, with short heat dissipation, realizing the high-efficiency heat dissipation of the protection board. The battery pack is divided into three major modules: the housing, the module, and the pre-installed upper cover. The structure is simple, the assembly is convenient, the product reliability is relatively high, and the overall mechanical strength of the pack is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0019] Figure 1 It is the exploded view of the overall assembly of the battery pack of the present invention.

[0020] Figure 2 It is the exploded view of the support pad fitting the end plate and the upper cover of the present invention.

[0021] Figure 3 It is the schematic diagram of the annular potting groove of the present invention.

[0022] Figure 4 It is the cross-sectional view of the connection of the bolts and nuts inside the annular potting groove of the present invention.

[0023] Figure 5 It is the internal schematic diagram of the upper cover of the present invention.

[0024] Figure 6 It is the schematic diagram of the battery cell array of the present invention.

[0025] Figure 7 This is a schematic diagram of the module component of the present invention.

[0026] Figure 8 This is a schematic diagram of the bottom case of the module component of the present invention.

[0027] Figure 9 This is an exploded view of the rivet nut and bolt of the present invention.

[0028] Figure 10 This is an exploded view of the potting glue and the rubber strip of the present invention.

[0029] Description of the drawings: 11 - bottom case, 12 - upper cover, 2 - module component, 3 - annular potting groove, 21 - soft-pack battery cell, 22 - buffer foam, 23 - epoxy board, 24 - adapter board, 25 - end plate, 26 - steel strip, 27 - graphene heat spreader, 28 - support pad, 121 - wire harness, 122 - antenna cover, 123 - protection board, 124 - thermal conductive silicone pad, 211 - tab, 31 - removable potting silicone, 32 - bolt, 33 - rivet nut, 34 - rubber strip. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Embodiment 1: Refer to Fig. Figure 1 、Fig. Figure 2 、Fig. Figure 4 、Fig. Figure 5 、Fig. Figure 6 、Fig. Figure 7As shown, a sodium (lithium) electric bicycle battery pack expansion design includes a bottom shell 11, a module assembly 2 is placed inside the bottom shell 11, an upper cover 12 is installed on the top of the bottom shell 11, the top edge of the bottom shell 11 and the bottom edge of the upper cover 12 together form an annular glue pouring groove 3, and the annular glue pouring groove 3 is filled with removable potting silicone 31. The module assembly 2 includes an array of soft-packed battery cells 21, and the side of the battery cell 21 is fastened with an end plate 25, and a support pad 28 is installed above the end plate 25. The bottom shell 11 adopts a flat sheet metal shell, which effectively protects the internal module assembly 2 while occupying a relatively small size. The annular structure of the annular glue pouring groove 3 eliminates the joint weakness of traditional linear glue pouring, and cooperates with the elastic deformation ability of silicone to maintain complete sealing under vehicle vibration conditions. The annular glue pouring groove 3 and the protective plate 123 integrated with the upper cover share the vertical space, which effectively improves the space utilization of the battery pack and is very beneficial to the expansion of the battery pack. After the removable potting silicone 31 is cured, a flexible adhesive layer is formed. During disassembly, a flat-blade screwdriver or other tools can be used to directly peel off the upper cover without loss, so that the bolts can be reused. Compared with the traditional epoxy resin potting disassembly, the damage rate is greatly reduced. The internal module assembly 2 is an array of soft-pack battery cells 21, which can greatly improve the space utilization rate. The end plate 25 applies a pre-tightening force to the battery cell 21 to suppress the expansion and deformation of the battery cell during charging and discharging. After the support pad 28 is bonded and fixed to the end plate 25, a pre-compression gap will be formed between its top and the inner surface of the upper cover, which limits the vertical jump of the module assembly 2 during product use. Compared with the traditional long screw constraint structure, the thickness of the end plate 25 of the present invention can be made very thin without being limited by the size of the long screw, which greatly reduces the overall size of the battery pack.

[0032] Refer to the attached Figure 2 , Attachment Figure 6 As shown, a sodium (lithium) electric bicycle battery pack expansion design, the support pad 28 is made of insulating material and is fixed between the end plate 25 and the upper cover 12 by bonding. The support pad 28 is made of insulating material and is used to block the direct contact between the end plate 25 and the upper cover 12. The end plate 25 and the upper cover 12 are both metal. The support pad 28 can avoid the risk of short circuit caused by metal contact, especially when the battery cell 21 is damp or condensed water intrudes, the insulation performance remains stable.

[0033] Refer to the attached Figure 3 , Attachment Figure 5As shown, a sodium (lithium) electric bicycle battery pack expansion design, the upper cover 12 is provided with a protective plate 123 and a thermally conductive silicone pad 124, the protective plate 123 is inverted on the inner surface of the upper cover, and forms a heat dissipation channel with the thermally conductive silicone pad 124, and the protective plate 123 is connected to the circuit module in the upper cover 12 through a wiring harness. The protective plate 123 is inverted on the inner surface of the upper cover 12, connected to the battery cell 21 module, and can monitor the voltage, current and temperature parameters in real time. When overcharge, overdischarge or short circuit abnormality is detected, the circuit module can be cut off to prevent thermal runaway. The inverted design of the protective plate 123 makes its metal substrate aluminum substrate fit closely with the thermally conductive silicone pad 124 to form a heat dissipation path, and the heat can be transferred to the metal shell of the upper cover 12 through the protective plate 123 for natural convection. The protective plate 123 and the annular glue filling groove 3 share the vertical height space, avoiding the space waste caused by the traditional parallel layout, and providing additional height direction space for the expansion of the battery cell 21.

[0034] Refer to the attached Figure 2 , Attachment Figure 6 , Attachment Figure 7 As shown, a capacity expansion design of a sodium (lithium) electric bicycle battery pack has a pole ear 211 on the top of the module assembly 2, and a graphene heat spreader 27 is attached to the pole ear 211. The thickness of the graphene heat spreader 27 is between 0.8mm and 1.2mm. The heat spreader 27 occupies a small height space and has a high thermal conductivity. The heat spreader is bonded to the pole ear of the battery cell. The pole ear is made of copper or aluminum sheet. The pole ear is connected to the inside of the battery cell. The heat spreader is used as a heat conduction channel to effectively reduce the temperature difference between different battery cells. The flexible characteristics of the graphene heat spreader 27 allow the steel belt 26 to apply a pre-tightening force without affecting the integrity of the thermal interface, and mechanical constraints and thermal management optimization are achieved simultaneously. There is also an insulating layer between the graphene heat spreader 27 and the upper cover 12 to ensure the insulation of the battery cell 21 and the upper cover 12.

[0035] Refer to the attached Figure 3 , Attachment Figure 4 , Figure 5 , Attachment Figure 10As shown in the figure, there is an expansion design for a sodium battery (lithium battery) electric bicycle battery pack. The annular potting groove 3 shares the height space with the protection board 123. The bottom shell 11 and the upper cover 12 are fixed by bolts 32. The removable potting silicone 31 is a modified two-component silicone or silicone gel, and the removable potting silicone 31 covers the entire bolt 32. The annular potting groove 3 shares the vertical space with the protection board 123 integrated with the upper cover 12, effectively improving the space utilization rate of the battery pack and greatly facilitating the expansion of the battery pack. The installation surfaces of the sheet metal upper cover 12 and the bottom shell 11 are realized by potting, with simple operation and excellent sealing effect, which is very suitable for mass production. The modified two-component silicone or silicone gel is a common glue on the market, with both low cost and price advantages, which is conducive to cost reduction of the product and improvement of the product competitiveness. The bolt 32 connects the bottom shell 11 and the upper cover 12. The bolt 32 is wrapped by glue, which solves the waterproof and airtight problems of the bolt 32 at the same time. The removable potting silicone 31 wrapping the bolt 32 effectively realizes anti-loosening.

[0036] Refer to the attached Figure 6 and the attached Figure 7 As shown in the figure, there is an expansion design for a sodium battery (lithium battery) electric bicycle battery pack. There is a buffer foam 22 between the battery cells 21. A transfer board 24 is welded to the top of the battery cell 21. An epoxy board 23 is pasted on the side of the battery cell 21. A steel strip 26 is fastened outside the epoxy board 23 and the end plate 25. The thickness of the end plate 25 is between 5 mm and 7 mm. The buffer foam 22 provides a buffer space for the expansion of the battery cells 21, preventing the battery cells 21 from expanding and squeezing each other and being damaged. The transfer board 24 realizes the connection of the battery cells 21. The epoxy board 23 pasted on the side is insulated from the bottom shell 11. The end plate 25 and the steel strip 26 are installed to restrain the expansion of the battery cells 21. When installing the steel strip 26, a pre-tightening force is applied to the battery cells 21, which is beneficial to improving the cycle life of the battery cells 21 and the overall stiffness of the module assembly 2, and reducing the risk of misalignment between single battery cells 21.

[0037] Refer to the attached Figure 8 As shown in the figure, there is an expansion design for a sodium battery (lithium battery) electric bicycle battery pack. The bottom shell 11 is a vertical rectangular structure with reinforcing ribs provided on the side walls. The bottom shell 11 has no flange protruding structure, and the overall shape is coordinated. This type of shell can be used as a positioning reference, and there is no obstruction on the installation path of components, which is convenient for internal assembly. The reinforcing ribs provided on the side walls can increase the overall stiffness of the side of the bottom shell, and the added reinforcing ribs can be formed into different shapes to optimize the product appearance.

[0038] Refer to the attached Figure 10 As shown in the figure, there is an expansion design for a sodium battery (lithium battery) electric bicycle battery pack. A glue-blocking strip 34 is provided on the groove surface of the annular potting groove 3, forming a sealing interface with the removable potting silicone 31. The glue-blocking strip 34 can beautify the appearance of the battery pack and also ensure the integrity of the sealing interface and provide a certain protection for the annular potting glue.

[0039] Refer to the attached Figure 9As shown in the figure, there is an expansion design for a sodium battery (lithium battery) electric bicycle battery pack. A press riveting nut 33 is pre-installed on the side of the upper cover 12. The press riveting nut 33 and the bolt 32 cooperate with each other to jointly fix the upper cover 12 and the bottom shell 11. The assembly and fastening method of the press riveting nut 33 and the bolt 32 can reduce the assembly time and ensure the uniformity of the bolt pre-tightening force, realizing the quick disassembly, assembly and repeated maintenance of the battery pack.

[0040] Refer to the appendix Figure 5 As shown in the figure, there is an expansion design for a sodium battery (lithium battery) electric bicycle battery pack. The upper cover 12 is integrated with an antenna cover 122. The antenna cover 122 is connected to the circuit module in the upper cover 12 through a wire harness 121. The antenna cover 122 covers the communication window area of the upper cover 12, improving the transmission efficiency of wireless signals and solving the shielding effect of the metal shell on electromagnetic waves. The antenna cover 122 is integrated in the non-expansion area of the upper cover 12, realizing the built-in of the wireless module by using the original structural space of the battery pack and avoiding the installation position occupied by the external antenna. The wire harness 121 is built-in to avoid external pulling and damage. The wire harness 121 uses a twisted shielded wire and is routed along the card slot preset on the inner wall of the upper cover 12 to avoid communication interruption caused by electromagnetic interference inside the battery pack. The wire harness 121 is reserved with an S-shaped bending section (the radius of curvature is greater than 5 times the wire diameter) to absorb the micro-deformation of the shell during the operation of the battery pack and avoid the fracture of the wire caused by repeated stretching.

[0041] The above-described embodiments and / or implementation manners are only used to illustrate the preferred embodiments and / or implementation manners for implementing the technology of the present invention, and do not impose any form of limitation on the implementation manners of the technology of the present invention. Any person skilled in the art, without departing from the scope of the technical means disclosed in the content of the present invention, can make some changes or modifications to other equivalent embodiments, but should still be regarded as the same technology or embodiment as the present invention in essence.

[0042] In this article, specific examples are used to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. The above is only the preferred implementation manner of the present application. It should be noted that due to the limited nature of written expression and objectively existing infinite specific structures, for those of ordinary skill in the art, without departing from the principles of the present application, several improvements, retouches or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, retouches, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should all be regarded as the protection scope of the present application.

Claims

1. A capacity expansion design for a sodium (lithium) electric bicycle battery pack, comprising a bottom shell (11), a module assembly (2) is placed inside the bottom shell (11), and an upper cover (12) is mounted on the top of the bottom shell (11), characterized in that: The top edge of the bottom shell (11) and the bottom edge of the upper cover (12) together form an annular glue potting groove (3), and the annular glue potting groove (3) is filled with removable potting silica gel (31). The module assembly (2) comprises an array of soft-pack battery cells (21), and the side of the array of battery cells (21) is fastened with an end plate (25), and a support pad (28) is installed above the end plate (25).

2. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1 is characterized by: The support pad (28) is made of an insulating elastic material and is fixed between the end plate (25) and the upper cover (12) by bonding.

3. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1 is characterized by: A protective plate (123) and a thermally conductive silicone pad (124) are provided inside the upper cover (12); the protective plate (123) is mounted upside down on the inner surface of the upper cover to form a heat dissipation channel with the thermally conductive silicone pad (124); and the protective plate (123) is connected to the circuit module in the upper cover (12) via a wiring harness.

4. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1 is characterized by: The module assembly (2) has a pole ear (211) at the top, and a graphene heat-spreading film (27) is attached to the pole ear (211), wherein the thickness of the graphene heat-spreading film (27) is between 0.8 mm and 1.2 mm.

5. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 3 is characterized by: The annular glue potting groove (3) shares a height space with the protection plate (123); the bottom shell (11) and the upper cover (12) are fixed by bolts (32); the detachable potting silicone (31) is a modified two-component silicone or silicone gel; the detachable potting silicone (31) covers the entire bolt (32).

6. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1 is characterized by: A buffer foam (22) is arranged between the battery cells (21), a transfer plate (24) is welded on the top of the battery cell (21), an epoxy plate (23) is attached to the side of the battery cell (21), a steel strip (26) is fastened to the outside of the epoxy plate (23) and the end plate (25), and the thickness of the end plate (25) is between 5 mm and 7 mm.

7. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1 is characterized by: The bottom shell (11) is a vertical rectangular structure, and the side wall of the bottom shell (11) is provided with reinforcing ribs.

8. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1 is characterized by: A rubber blocking strip (34) is provided on the groove surface of the annular glue pouring groove (3) to form a sealing interface with the detachable potting silica gel (31).

9. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1 is characterized by: A rivet nut (33) is pre-installed on the side of the upper cover (12), and the rivet nut (33) and the bolt (32) cooperate with each other to fix the upper cover (12) and the bottom shell (11).

10. The capacity expansion design of a sodium (lithium) electric bicycle battery pack according to claim 1, characterized in that: The upper cover (12) is integrated with an antenna cover (122), and the antenna cover (122) is connected to a circuit module in the upper cover (12) via a wiring harness (121).

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