A composite connecting plate for internal busbar and heat dissipation of multi-string parallel cell module

Abstract

This utility model discloses a composite connecting piece for internal current charging and heat dissipation in multi-series parallel battery cell modules. It is suitable for current charging and heat dissipation within battery modules, comprising a copper layer, a conductive sheet used to carry the main busbar between cells and conduct heat; nickel layers, located at the four corners of the copper layer, used to provide electrical connection with the cell terminals; and a welding structure, in which the nickel layer is fixedly connected to the copper layer by resistance spot welding. This utility model not only fully utilizes the excellent conductivity and heat dissipation properties of the copper layer, effectively reducing the busbar impedance inside the module, reducing voltage loss, and improving high current carrying capacity, but also combines the good weldability and corrosion resistance of nickel material, improving the strength and long-term stability of the spot weld joints and avoiding poor contact problems caused by incomplete soldering or desoldering.

Description

Technical Field

[0001] This utility model relates to the field of batteries, specifically to a composite connecting piece for internal current convergence and heat dissipation in multi-series parallel battery cell modules. Background Technology

[0002] With the widespread application of power battery systems in new energy vehicles, energy storage devices, and portable electronic devices, the cell connection structure inside the battery module plays a crucial role in the overall performance, safety, and lifespan of the battery pack. In multi-series parallel module structures, the connecting pieces not only need to bear the function of high current collection but also need to have good heat dissipation performance and welding stability. Therefore, the structural design and material selection of the connecting pieces have become key technical points in battery system engineering.

[0003] In existing technologies, aluminum or nickel sheets are typically used as connectors inside battery modules. Pure nickel sheets offer good solderability and corrosion resistance, but their electrical conductivity is relatively poor, making it difficult to meet the requirements of high current paths. While copper materials have excellent electrical and thermal conductivity, they are prone to incomplete soldering and desoldering during spot welding, resulting in poor process stability, and bare copper is easily corroded.

[0004] To compensate for the performance limitations of single materials, some technologies have proposed using copper-nickel composite connectors, leveraging the synergistic effect of the two materials to achieve comprehensive optimization of conductivity, solderability, and mechanical properties. However, existing copper-nickel composite connectors are mostly integral composites, lacking structural specificity, and still have certain shortcomings in terms of the fit between battery terminals and connectors, spot weld strength, current path distribution, and heat dissipation efficiency. For example, some products, due to unreasonable connection point design or uneven distribution of composite layers, are prone to problems such as uneven current convergence, increased cell contact resistance, and heat accumulation, thereby affecting the stability and safety of module operation.

[0005] Furthermore, for some compact module designs or those with limited installation space, conventional one-piece composite connectors are insufficient to meet the requirements for installation flexibility and structural adaptability. Therefore, there is an urgent need for a composite connector with a more optimized structure, a more rational distribution of functional areas, and applicability to various module layouts, in order to improve electrical connection efficiency, welding reliability, and thermal management capabilities, thereby driving the performance upgrade of battery systems. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a composite connecting piece for internal current convergence and heat dissipation in multi-series parallel battery cell modules, effectively overcoming the shortcomings of existing technologies.

[0007] This utility model is achieved through the following technical solution: a composite connecting piece for internal current convergence and heat dissipation in multi-series parallel battery cell modules, suitable for current convergence and heat dissipation inside battery modules, comprising:

[0008] The copper layer is a conductive sheet used to carry the main busbar between the battery cells and to conduct heat away.

[0009] A nickel layer is disposed at the four corners of the copper layer to provide electrical connection with the battery cell terminals;

[0010] The welded structure is wherein the nickel layer is fixedly connected to the copper layer by resistance spot welding;

[0011] The groove structure has a plurality of grooves on the nickel layer that are adapted to the battery cell terminals. Each groove is used to accommodate the recessed steel shell part at the top of the battery cell terminal so as to achieve a close fit and welding.

[0012] As a preferred technical solution, the copper layer is made of highly conductive copper or copper alloy material with a thickness of 0.3 to 1.0 mm, and the nickel layer is made of nickel or nickel-plated metal plate with a thickness of 0.1 to 0.3 mm.

[0013] As a preferred technical solution, the copper layer and the nickel layer are combined using one or more of the following processes: vacuum thermocompression welding, laser welding, friction stir welding, or brazing.

[0014] As a preferred technical solution, each groove is an annular or arc-shaped recessed structure, used to correspond to the concave surface of the steel shell of the cylindrical battery cell electrode.

[0015] As a preferred technical solution, the welding structure is an annular resistance spot welding position, which is symmetrically arranged along the outer edge of the nickel layer or around the contact surface with the copper layer.

[0016] As a preferred technical solution, the composite connecting piece is connected in parallel with the terminals of multiple battery cells through the four corner nickel layers to form a single-cell busbar structure of the battery module.

[0017] As a preferred technical solution, the four corners of the copper layer are provided with rounded corner structures to eliminate stress.

[0018] As a preferred technical solution, a hollow area is provided in the middle of the copper layer to avoid increasing the tension of the component.

[0019] The beneficial effects of this utility model are: This utility model provides a composite connecting piece, which achieves efficient electrical contact and welding adaptation between the battery cell terminal and the connecting piece by setting nickel layer structures in the four corner areas of the copper layer and using spot welding to reliably connect the nickel layer and the copper layer.

[0020] This structure not only makes full use of the excellent conductivity and heat dissipation of copper layer, which can effectively reduce the bus impedance inside the module, reduce voltage loss, and improve the high current carrying capacity, but also combines the good solderability and corrosion resistance of nickel material, which improves the firmness and long-term stability of spot welds and avoids poor contact problems caused by poor soldering or desoldering.

[0021] Meanwhile, the nickel layer is placed at the four corners of the copper layer to form a reasonably distributed multi-point contact structure, which is conducive to achieving uniform current convergence of the cell array, improving heat dissipation efficiency, reducing the risk of temperature rise at local hot spots, and ensuring the overall thermal stability of the module.

[0022] In addition, the nickel layer surface has a groove structure that can fit the recessed area on the top of the steel shell of the battery cell terminal, improve the welding fit and mechanical stability, and meet the usage requirements of different battery cell layout structures. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure 1 ;

[0025] Figure 2 This is a schematic diagram of the overall structure of the present invention. Figure 2 ;

[0026] Figure label:

[0027] 1. Copper layer; 2. Nickel layer; 3. Groove structure. Detailed Implementation

[0028] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0029] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0030] like Figure 1 and Figure 2As shown, this utility model proposes a composite connecting piece for internal current charging and heat dissipation in multi-series parallel battery cell modules, suitable for electrical connections and thermal management within battery modules. The composite connecting piece mainly comprises a copper layer 1, a nickel layer 2, a welding structure, and a groove structure 3. The copper layer 1 is the foundation of the entire structure, made of highly conductive copper or copper alloy material, with a preferred thickness of 0.3–1.0 mm to ensure good current carrying capacity and heat dissipation efficiency during high-current discharge or charging of the battery cells. The copper layer 1 is flat and unfolds to connect the main current charging paths between multiple battery cells. It also serves as a heat diffusion channel, uniformly conducting the heat generated during battery cell operation to the entire copper layer 1, thereby balancing the module temperature rise and preventing localized overheating.

[0031] Several nickel layers 2 are disposed at the four corners of the copper layer 1, each nickel layer 2 being a locally distributed structure covering a designated location on the copper layer 1. The nickel layers 2 are made of nickel or nickel-plated metal sheets with a thickness of 0.1–0.3 mm to provide good spot welding performance and corrosion resistance. Since nickel is easier to use for high-strength, low-failure-welding resistance spot welding connections compared to copper, placing the nickel layers 2 in localized areas of the copper layer 1 not only ensures the weld strength of the connection structure but also protects the copper layer 1 in humid or corrosive atmospheres, extending the module's lifespan. To further improve the welding bonding effect and the stability of the electrical connection, several groove structures 3 are provided on each nickel layer 2. These grooves are preferably annular or arc-shaped recesses, their size and contour matching the steel shell recesses on the top of the cylindrical battery cell terminals. This allows for precise alignment, ensuring the terminals are firmly embedded in the grooves during welding, increasing the contact area and mechanical bonding stability of the weld, thereby significantly reducing contact resistance and improving the module's operational stability.

[0032] To achieve a reliable bond between copper layer 1 and nickel layer 2, one or more of various metal composite processes are employed, including vacuum thermocompression welding, laser welding, friction stir welding, or brazing. These processes enable high-strength metallurgical bonding between the two metals without compromising the conductivity and structural integrity of the materials, ensuring that the composite connector maintains good structural stability and conductivity under electrical and thermal stress. Specifically, a ring-shaped resistance spot welding structure is used, with weld points symmetrically arranged along the outer edge of each nickel layer 2 or at the contact boundary with the copper layer 1. This promotes uniform heat distribution during welding and effectively prevents material warping or weld point delamination caused by localized stress concentration.

[0033] In practical applications, this composite connector connects to multiple battery cell terminals point-to-point via nickel layer 2 areas at its four corners, forming a simple and evenly distributed single-cell busbar. Each terminal corresponds to a groove for positioning the welding point, thus achieving parallel current convergence within the entire module. This ensures the symmetry and electrical balance of the current convergence path and facilitates rapid assembly and reliable positioning of the entire structure within the module housing. Current convergence and heat dissipation are achieved through copper layer 1, while stable welding and corrosion resistance are provided by locally placed nickel layers 2. This composite connector optimizes the structure while balancing welding efficiency, electrical performance, and thermal management capabilities, making it particularly suitable for power battery module systems with high requirements for performance consistency and safety.

[0034] In this embodiment, rounded corner structures 4 are provided at the four corners of the copper layer 1 to eliminate stress. In traditional right-angle structures, the electric field and current density will increase sharply at the right-angle corners (edge ​​effect), resulting in increased local resistance and severe heat generation. The temperature rise may cause the diaphragm to shrink, the electrolyte to decompose, or even thermal runaway.

[0035] A hollow area 5 is set in the middle of the copper layer 1 to avoid increasing the tension of the component.

[0036] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope defined in the claims.

Claims

1. A composite tab for internal busbar and heat dissipation of multi-string parallel cell modules, characterized in that, Suitable for current charging and heat dissipation inside battery modules, including: The copper layer (1) is a conductive sheet used to carry the main busbar between the battery cells and to conduct heat out. Nickel layers (2) are disposed at the four corners of the copper layer (1) to provide electrical connection with the battery cell terminals; The nickel layer (2) is fixedly connected to the copper layer (1) by resistance spot welding. The groove structure (3) has a plurality of grooves on the nickel layer (2) adapted to the battery cell electrode post. Each groove is used to accommodate the recessed steel shell part at the top of the battery cell electrode post so as to achieve a bonding weld.

2. The composite tab for internal busbar and heat dissipation of multi-string parallel cell module according to claim 1, characterized in that: The copper layer (1) is made of highly conductive copper or copper alloy material with a thickness of 0.3 to 1.0 mm, and the nickel layer (2) is made of nickel or nickel-plated metal plate with a thickness of 0.1 to 0.3 mm.

3. The composite connecting piece for internal current convergence and heat dissipation in a multi-series parallel battery cell module according to claim 1, characterized in that: The copper layer (1) and the nickel layer (2) are combined using one or more of the following processes: vacuum thermocompression welding, laser welding, friction stir welding, or brazing.

4. The composite connecting piece for internal current convergence and heat dissipation in a multi-series parallel battery cell module according to claim 1, characterized in that: Each groove is an annular or arc-shaped recessed structure, used to correspond to the concave surface of the steel shell of the cylindrical battery cell terminal.

5. The composite connecting piece for internal current convergence and heat dissipation in a multi-series parallel battery cell module according to claim 1, characterized in that: The welding structure is an annular resistance spot welding position, which is symmetrically arranged along the outer edge of the nickel layer (2) or around the contact surface with the copper layer (1).

6. The composite connecting piece for internal current convergence and heat dissipation in a multi-series parallel battery cell module according to claim 1, characterized in that: The composite connecting piece is connected in parallel with the terminals of multiple battery cells through the four corner nickel layers (2) to form a single-cell busbar structure of the battery module.

7. The composite connecting piece for internal current convergence and heat dissipation in a multi-series parallel battery cell module according to claim 1, characterized in that: The copper layer (1) has rounded corner structures (4) at its four corners to relieve stress.

8. The composite connecting piece for internal current bus and heat dissipation in a multi-series parallel battery cell module according to claim 1, characterized in that: A hollow area (5) is provided in the middle of the copper layer (1) to avoid increasing the tension of the component.

Images