Flexible wiring connection structure for polymer lithium-ion battery pack

Abstract

The utility model discloses a kind of flexible circuit connection structure of polymer lithium ion battery pack, it includes flexible substrate, circuit conducting mechanism and assembly positioning mechanism.Circuit conducting mechanism is located on the surface of flexible substrate, including conductive circuit, connecting terminal and stress buffer part, stress buffer part is wave-shaped or serpentine trace structure, for absorbing the stress generated by substrate deformation;Assembly positioning mechanism includes positioning frame and alignment window, alignment window corresponds with connecting terminal, for guiding battery electrode sheet alignment assembly.The present application can realize the stable electrical connection of battery pack under tiny deformation, and improve assembly positioning precision.

Description

Technical Field

[0001] This utility model relates to the field of electrical connection structure technology for battery components, and in particular to a flexible circuit connection structure for polymer lithium-ion battery packs. Background Technology

[0002] Polymer lithium-ion battery packs, as high-energy-density, lightweight, and customizable energy storage devices, are widely used in consumer electronics, power tools, drones, and new energy vehicles. In the composition of a battery pack, multiple individual cells need to be connected in series or parallel via wiring structures to meet different voltage and capacity requirements. Traditional wiring methods often use rigid PCB boards or metal wire soldering, which can achieve electrical conduction and signal transmission to a certain extent. As battery modules develop towards miniaturization and high integration, the requirements for internal space utilization efficiency and structural adaptability are increasing. However, existing connection structures have room for further optimization in terms of geometry and connection point stability when dealing with the minute deformations of the battery pack during charging and discharging. Continuous stress concentration may affect the long-term reliability of the connection area. Furthermore, in mass assembly processes, traditional connection methods have limited tolerance for positional accuracy, increasing assembly difficulty. Utility Model Content

[0003] The purpose of this utility model is to provide a flexible circuit connection structure for polymer lithium-ion battery packs, which solves the problems mentioned in the background art.

[0004] This utility model is implemented as follows: a flexible circuit connection structure for a polymer lithium-ion battery pack includes a flexible substrate, a circuit conduction mechanism, and an assembly positioning mechanism, wherein:

[0005] The circuit conduction mechanism is fixed to the surface of the flexible substrate and is used to establish an electrical connection between multiple battery cells. The circuit conduction mechanism includes conductive lines, multiple connection terminals, and at least one stress buffer. The conductive lines are laid on the flexible substrate, and the multiple connection terminals are respectively located at the ends of the conductive lines. The stress buffer is integrated into the path of the conductive lines and has an extensible geometric configuration to absorb stress when the flexible substrate is bent or stretched.

[0006] The assembly positioning mechanism is fixed to the flexible substrate and has a preset alignment feature to guide the connection terminal and the electrode of the battery cell to be accurately aligned during assembly.

[0007] Optionally, the stress buffer section is a continuous wavy or serpentine trace section, which is composed of multiple alternating and opposite circular arc traces connected in sequence, and the extension direction of the stress buffer section is consistent with the main direction of the conductive trace.

[0008] Optionally, the assembly positioning mechanism includes a positioning frame and multiple alignment windows. The positioning frame is stacked and fixed on the upper surface of the flexible substrate. The alignment windows penetrate the positioning frame, and the position of each alignment window corresponds to the position of a connection terminal. The inner sidewall of the alignment window defines the access position of the battery cell electrode.

[0009] Optionally, the assembly positioning mechanism further includes a plurality of limiting flanges, which extend integrally from the inner sidewall of each alignment window and face the surface of the flexible substrate. An insertion gap for accommodating the battery cell electrode sheet is formed between the bottom surface of the limiting flange and the upper surface of the flexible substrate.

[0010] Optionally, the surface area of ​​the connecting terminal is larger than the cross-sectional area of ​​the conductive line, and the length of the connecting terminal along the insertion direction of the battery cell electrode sheet is greater than its width perpendicular to the insertion direction, forming a long strip-shaped welding area.

[0011] Optionally, the present invention further includes a welding reinforcement structure, which includes a reinforcing sheet and an adhesive layer. The reinforcing sheet is attached to the side of the flexible substrate away from the connecting terminals through the adhesive layer. The position of the reinforcing sheet coincides with the position area of ​​all connecting terminals. The material hardness of the reinforcing sheet is higher than that of the flexible substrate.

[0012] Optionally, the positioning frame is provided with multiple pre-set bending grooves, which are V-shaped grooves opened on the surface of the positioning frame. The flexible circuit connection structure is bent along the pre-set bending grooves to fit the three-dimensional shape of the battery pack.

[0013] Optionally, the present invention further includes a surface covering mechanism, the surface covering mechanism including an insulating covering film, the insulating covering film covering the outer surface of the circuit conduction mechanism, the insulating covering film having a plurality of pad openings, the positions of the pad openings corresponding one-to-one with the positions of the connecting terminals, and the connecting terminals being exposed through the pad openings.

[0014] Optionally, the positioning frame is provided with a ring of reinforcing ribs around its periphery. The reinforcing ribs are integrally formed protruding structures, which improve the overall structural rigidity of the positioning frame.

[0015] This utility model provides a flexible circuit connection structure for polymer lithium-ion battery packs, which has the following advantages:

[0016] This flexible circuit connection structure for polymer lithium-ion battery packs incorporates a stress buffer within the circuit conduction mechanism. This stress buffer, with its wavy or serpentine geometry, elastically expands and contracts under external forces. When the battery pack undergoes minor deformation due to thermal expansion and contraction during charging and discharging, the resulting mechanical stress is absorbed by the stretching or compression of the stress buffer, preventing direct stress transmission to the welding points between the connection terminals and battery electrodes. This significantly improves the long-term structural stability and electrical reliability of the connection points. Simultaneously, the assembly positioning mechanism, with its positioning frame and alignment window, acts as a physical guide during assembly, precisely guiding the battery electrode pieces to the predetermined area of ​​the connection terminal. Combined with the elongated connection terminal design, this greatly expands the positional tolerance range of the welding operation, reduces the need for high-precision alignment equipment, and simplifies the assembly process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the bottom surface of the present invention;

[0019] Figure 3 This is a top view of the present invention.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. Flexible substrate; 2. Conductive circuit; 3. Connecting terminal; 4. Stress buffer; 5. Positioning frame; 6. Alignment window; 7. Limiting flange; 8. Insertion gap; 9. Welding reinforcement structure; 10. Reinforcing sheet; 11. Adhesive layer; 12. Insulating cover film; 13. Pad opening; 14. Bent pre-set groove; 15. Reinforcing rib; 16. Battery cell; 17. Electrode sheet. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figures 1 to 3This utility model provides a flexible circuit connection structure for polymer lithium-ion battery packs, which is applied to the electrical interconnection of multiple polymer lithium-ion battery cells 16. Through specific geometric construction and composite layering design, this structure provides precise physical alignment guidance during battery pack assembly and buffers and absorbs mechanical stress generated by thermal expansion and contraction during battery pack operating cycles.

[0024] Please see Figure 1 , Figure 2 and Figure 3 This utility model provides a technical solution: a flexible circuit connection structure for a polymer lithium-ion battery pack, the overall structure of which includes a flexible substrate 1, a circuit conduction mechanism fixed on the flexible substrate 1, and an assembly positioning mechanism fixed on the flexible substrate 1.

[0025] The flexible substrate 1 is the carrier of the entire connection structure, and its material is a polymer film with good insulation properties and mechanical flexibility, such as polyimide film. The physical form of the flexible substrate 1 is a thin sheet, and its outline is set according to the specific arrangement of the battery pack to be connected.

[0026] The conductive circuit is disposed on the surface of the flexible substrate 1, forming a path for charge transfer between the battery cells 16. This conductive circuit mainly includes multiple conductive lines 2, multiple connection terminals 3, and at least one stress buffer 4. The conductive lines 2 are formed on the upper surface of the flexible substrate 1 using a conductive material, such as rolled copper foil, through an etching process to create a predetermined circuit pattern. Each conductive line 2 has a main orientation that defines the main path direction of current between two connection points.

[0027] The plurality of connection terminals 3 are respectively disposed at the ends of each conductive line 2 or at designated connection points. Each connection terminal 3 is a conductive area with a treated surface, which directly contacts and electrically connects to the electrode plate 17 of the battery cell 16. In a specific embodiment, the surface area of ​​the connection terminal 3 is larger than the cross-sectional area of ​​the conductive line 2 to which it is connected. This design reduces the contact resistance at the connection point and increases the current carrying capacity and heat dissipation area. Furthermore, the geometry of the connection terminal 3 is designed as an elongated welding area, the length of which along the insertion direction of the electrode plate 17 is greater than its width perpendicular to the insertion direction. This elongated geometry provides a positional tolerance in one direction for the positioning of the electrode plate 17 during assembly and welding.

[0028] The stress buffer 4 is a key structure in the circuit conduction mechanism; physically, it is part of the conductive circuit 2 and integrated into the path of the conductive circuit 2. Please refer to the following for details. Figure 2The stress buffer section 4 has a geometric configuration that is extendable. In a preferred embodiment, the stress buffer section 4 is specifically manifested as a continuous wavy or serpentine trace segment. This wavy or serpentine trace segment is composed of multiple alternating, oppositely oriented arc-shaped trace segments connected sequentially. These arc-shaped trace segments together form a geometric structure that can elastically expand and contract in a two-dimensional plane. The overall extension direction of the stress buffer section 4 is consistent with the main direction of the conductive line 2. When the polymer lithium-ion battery pack undergoes thermal expansion and contraction due to temperature changes during charging and discharging, resulting in a small relative displacement between the battery cells 16, this displacement is transmitted to the flexible substrate 1 through the electrode sheet 17, applying tensile or compressive stress to the conductive line 2. At this time, the wavy or serpentine geometric configuration of the stress buffer section 4 will undergo corresponding elastic deformation, that is, the curvature of multiple arc-shaped trace segments changes, and the trace segments are stretched or compressed within the elastic range, thereby absorbing most of the mechanical stress and avoiding stress concentration transmission to the rigid welding point between the connecting terminal 3 and the electrode sheet 17.

[0029] The assembly positioning mechanism is fixed to the flexible substrate 1 and has preset alignment features, providing physical guidance and positioning during the assembly process of connecting the electrode sheet 17 of the battery cell 16 to the connecting terminal 3. (See also...) Figure 1 and Figure 3 The assembly positioning mechanism includes a positioning frame 5 and multiple alignment windows 6 formed on the positioning frame 5. The positioning frame 5 is made of an insulating material with a certain structural rigidity, such as polycarbonate or polyethylene terephthalate sheet. The positioning frame 5 is fixed to the upper surface of the flexible substrate 1 in a laminated structure by adhesive or hot pressing process.

[0030] The alignment window 6 is a through hole extending through the thickness of the positioning frame 5. The position of each alignment window 6 precisely corresponds to the position of a connection terminal 3 on the flexible substrate 1. During assembly, the electrode sheet 17 of the battery cell 16 needs to pass through the corresponding alignment window 6 to contact the connection terminal 3 below. Therefore, the inner wall of the alignment window 6 defines the access position of the electrode sheet 17, serving as a guide for coarse positioning.

[0031] To achieve more precise positioning and temporary fixation before assembly, the assembly positioning mechanism also includes multiple limiting flanges 7. (See also...) Figure 2Each limiting flange 7 extends integrally from the inner sidewall of an alignment window 6 and faces the upper surface of the flexible substrate 1. An insertion gap 8 with a specific height is formed between the bottom surface of the limiting flange 7 and the upper surface of the flexible substrate 1. The height of this insertion gap 8 matches the thickness of the electrode sheet 17 of the battery cell 16 to be inserted. During assembly, after the electrode sheet 17 passes through the alignment window 6, its front end is further guided and slides into this insertion gap 8. At this time, the electrode sheet 17 is clamped between the bottom surface of the limiting flange 7 and the top surface of the connecting terminal 3, its vertical position is fixed, and it remains in close contact with the connecting terminal 3, creating good contact conditions for subsequent welding processes.

[0032] In one specific embodiment, the present invention further includes a welded reinforcement structure 9. See also... Figure 3 The welding reinforcement structure 9 includes a reinforcing sheet 10 and an adhesive layer 11. The reinforcing sheet 10 is made of a material with a higher hardness than the flexible substrate 1, such as a thin steel sheet or an epoxy resin board. The reinforcing sheet 10 is attached to the side of the flexible substrate 1 facing away from the connecting terminals 3 via the adhesive layer 11, i.e., the facing side of the flexible substrate 1. The size and position of the reinforcing sheet 10 coincide with the overall position area of ​​all connecting terminals 3 on the flexible substrate 1. During ultrasonic welding or laser welding, the welding head applies a certain pressure to the electrode sheet 17 and the connecting terminals 3. At this time, the reinforcing sheet 10 located directly below provides rigid local support for the flexible substrate 1, preventing the flexible substrate 1 from denting or deforming under this pressure, thereby ensuring the effective transfer of welding energy and the stability of welding quality.

[0033] To protect the conductive structure and achieve electrical insulation, this invention also includes a surface covering mechanism. Specifically, this surface covering mechanism is an insulating covering film 12. The insulating covering film 12, typically also made of polyimide, is applied to the outer surface of the conductive structure via a lamination process, completely covering all conductive lines 2 and stress buffer parts 4. The insulating covering film 12 has multiple solder pad openings 13. The position of each solder pad opening 13 corresponds one-to-one with the position of a connecting terminal 3, and its size matches the soldering area of ​​the connecting terminal 3. The connecting terminal 3 is exposed through these solder pad openings 13 for soldering to the external electrode sheet 17.

[0034] To accommodate the three-dimensional structure of the battery pack, the positioning frame 5 is also provided with multiple pre-set bending grooves 14. (See also...) Figure 1The bending preset grooves 14 are specifically V-shaped grooves or indentations opened on the surface of the positioning frame 5. These bending preset grooves 14 are preset stress concentration lines. When bending is required, the entire flexible circuit connection structure will bend precisely along these preset lines, thereby being able to closely fit the three-dimensional shape of the battery pack, such as wrapping around the corners of the battery pack.

[0035] To improve the overall mechanical performance of the assembly positioning mechanism, a ring of reinforcing ribs 15 is provided around the periphery of the positioning frame 5. The reinforcing ribs 15 are protruding structures integrally formed with the positioning frame 5. The reinforcing ribs 15 increase the moment of inertia of the edge section of the positioning frame 5, thereby significantly improving the overall structural rigidity of the positioning frame 5, making it less prone to twisting or deformation during handling and assembly, and maintaining the accuracy of the relative positions between all the alignment windows 6.

[0036] The working process and assembly procedure of this utility model are as follows: First, the flexible circuit connection structure of this utility model is placed on the assembly station. An operator or automated equipment picks up a battery cell 16 and aligns its electrode 17 with a positioning window 6 on the positioning frame 5. Then, the electrode 17 is inserted into the positioning window 6, with the tip of the electrode 17 sliding into the insertion gap 8 below the limiting flange 7 and smoothly covering the exposed connection terminal 3. Next, the welding equipment welds the overlapping area of ​​the electrode 17 and the connection terminal 3 to form a strong electrical connection. This process is repeated until the electrode 17 of all battery cells 16 is connected to the corresponding connection terminal 3. If the battery pack has a three-dimensional structure, the entire connection structure is bent along the pre-set bending groove 14 on the positioning frame 5 to conform to the shape of the battery pack. During subsequent use of the battery pack, when the charging and discharging cycles cause slight changes in the size of the battery cells 16, the resulting mechanical stress is absorbed and released by the stress buffer part 4 in the conductive circuit 2 through its own geometric deformation.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A flexible circuit connection structure for a polymer lithium-ion battery pack, characterized in that, It includes a flexible substrate (1), a circuit conduction mechanism, and an assembly positioning mechanism, wherein: The circuit conduction mechanism is fixed on the surface of the flexible substrate (1). The circuit conduction mechanism includes a conductive line (2), a plurality of connecting terminals (3) and at least one stress buffer (4). The conductive line (2) is laid on the flexible substrate (1). The plurality of connecting terminals (3) are respectively disposed at the ends of the conductive line (2). The stress buffer (4) is integrated into the path of the conductive line (2). The stress buffer (4) has an extendable geometric configuration. The assembly positioning mechanism is fixed to the flexible substrate (1). The assembly positioning mechanism has a preset alignment feature, which defines the connection position of the connecting terminal (3) and the electrode sheet (17) of the battery cell (16).

2. The flexible circuit connection structure of a polymer lithium-ion battery pack according to claim 1, characterized in that: The stress buffer section (4) is a continuous wavy or serpentine trace section. The wavy or serpentine trace section is composed of multiple alternating and opposite arc-shaped trace sections connected in sequence. The extension direction of the stress buffer section (4) is consistent with the main direction of the conductive trace (2).

3. The flexible circuit connection structure of a polymer lithium-ion battery pack according to claim 1, characterized in that: The assembly positioning mechanism includes a positioning frame (5) and a plurality of alignment windows (6). The positioning frame (5) is fixed to the upper surface of the flexible substrate (1) in a stacked structure. The alignment windows (6) penetrate the positioning frame (5), and the position of each alignment window (6) corresponds to the position of a connection terminal (3). The inner sidewall of the alignment window (6) defines the access position of the electrode sheet (17).

4. The flexible circuit connection structure of a polymer lithium-ion battery pack according to claim 3, characterized in that: The assembly positioning mechanism also includes a plurality of limiting flanges (7), which extend integrally from the inner sidewall of each of the alignment windows (6) and face the surface of the flexible substrate (1). An insertion gap (8) is formed between the bottom surface of the limiting flange (7) and the upper surface of the flexible substrate (1).

5. The flexible circuit connection structure of a polymer lithium-ion battery pack according to claim 1, characterized in that: The surface area of ​​the connecting terminal (3) is larger than the cross-sectional area of ​​the conductive line (2), and the connecting terminal (3) forms a long strip-shaped welding area.

6. The flexible circuit connection structure of a polymer lithium-ion battery pack according to claim 1, characterized in that: It also includes a welding reinforcement structure (9), which includes a reinforcing sheet (10) and an adhesive layer (11). The reinforcing sheet (10) is attached to the flexible substrate (1) away from the back surface of the connecting terminal (3) through the adhesive layer (11). The position of the reinforcing sheet (10) coincides with the position area of ​​all the connecting terminals (3).

7. The flexible circuit connection structure of a polymer lithium-ion battery pack according to claim 3, characterized in that: The positioning frame (5) is provided with a plurality of pre-set bending grooves (14), which are V-shaped grooves opened on the surface of the positioning frame (5).

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