Soft and hard copper bar welding structure

Abstract

The utility model provides a soft and hard copper bar welding structure, which comprises a soft copper bar, a hard copper bar and a welding assembly, the soft copper bar and the hard copper bar comprise a welding part and a non-welding part, the soft copper bar welding part is provided with a soft copper bar welding positioning hole and a soft copper bar tooth-shaped part, and the hard copper bar welding part is provided with a hard copper bar welding positioning hole and a hard copper bar tooth-shaped part; the welding assembly comprises a welding positioning plate and a welding piece, and positioning bosses are arranged at the two ends of the welding positioning plate respectively. The tooth-shaped parts of the soft copper bar and the hard copper bar are mutually embedded, the soft copper bar welding positioning hole and the hard copper bar welding positioning hole are respectively matched with the positioning bosses at the two ends of the welding positioning plate in a positioning manner, and the welding sheet is clamped between the tooth-shaped parts of the soft copper bar and the hard copper bar and the welding positioning plate; according to the welding structure, the soft copper bar and the hard copper bar are embedded through the tooth-shaped part, and then the positioning boss on the positioning plate penetrates through the soft copper bar welding positioning hole and the hard copper bar welding positioning hole at the same time, so that accurate positioning of the welding part of the soft copper bar and the hard copper bar before welding is ensured, personal errors are reduced, and the welding precision is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of copper busbar welding technology, in particular to a soft and hard copper busbar welding structure. Background Art

[0002] New energy vehicles (NEVs) are a new type of transportation, and one of their core components is the battery system. The performance of the battery system directly impacts the vehicle's range, power, and safety. A key component of the battery system is the battery module, which can be connected primarily in series or in parallel. Copper busbars are crucial components for both connections. Copper busbars are high-current conductive materials widely used in new energy vehicles, electric locomotives, and power electronics. The welding quality of the copper busbars directly impacts the performance and service life of the battery module. With the rapid development of the NEV market, increasingly stringent performance requirements for battery systems are driving even higher demands on copper busbar welding quality.

[0003] The soft and hard integrated copper busbar is made by welding soft copper busbar and hard copper busbar. It has flexible installation performance. In particular, the soft busbar part can be bent and twisted arbitrarily by hand or with the help of a bending machine, which can improve the installation speed and practicality of the product.

[0004] In the existing technology, soft and hard copper busbars are welded using two welding methods: diffusion welding and induction welding. The two welding processes take a long time. After welding, the product will be subjected to high temperature for a long time, resulting in high-temperature annealing and oxidation. As a result, the hardness of the hard copper busbar and the soft copper busbar products themselves will be reduced due to the high temperature, which will reduce the mechanical life of the product in subsequent use and there will be a risk of the product breaking. At the same time, the use of heat shrink tubing, plastic dipping and other insulation post-treatments after welding is difficult to better meet the insulation and heat resistance requirements of new energy vehicle battery modules. Therefore, the inventors have improved the design of the welding structure of the soft and hard copper busbars to make their welding accuracy higher, the product stability stronger, and the insulation and heat resistance better. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings and deficiencies of the existing technology and provide a soft and hard copper busbar welding structure. The technical solutions adopted by this utility model are as follows:

[0006] A soft and hard copper bar welding structure comprises a soft copper bar and a hard copper bar, and a welding assembly, wherein the soft copper bar comprises a soft copper bar welding portion and a non-welding portion, and the hard copper bar comprises a hard copper bar welding portion and a non-welding portion; the soft copper bar welding portion is provided with a soft copper bar welding positioning hole and a soft copper bar tooth-shaped portion, and the hard copper bar welding portion is provided with a hard copper bar welding positioning hole and a hard copper bar tooth-shaped portion; the welding assembly comprises a resistance welding lower electrode and a resistance welding upper electrode, a welding positioning plate and a welding piece, and positioning bosses are respectively provided at both ends of the welding positioning plate; the soft copper bar tooth-shaped portion is engaged with the hard copper bar tooth-shaped portion, and the soft copper bar welding positioning hole and the hard copper bar welding positioning hole are respectively positioned and matched with the positioning bosses at both ends of the welding positioning plate, and the welding piece is sandwiched between the soft and hard copper bar tooth-shaped portions and the welding positioning plate.

[0007] Preferably, a soft copper bar processing step is formed between the soft copper bar welding portion and the non-welding portion, a hard copper bar processing step is formed between the hard copper bar welding portion and the non-welding portion, and the welding positioning plate is embedded between the soft and hard copper bar processing steps.

[0008] Preferably, the thickness of the soft copper bar welding part and the hard copper bar welding part are both smaller than the non-welding part, and the thickness of the welding positioning plate is adapted to the depth of the soft and hard copper bar processing steps, so that the lower surface of the welding positioning plate is flush with the lower surfaces of the soft copper bar and the hard copper bar; for welding of complex shapes or large structures, this embedded positioning plate can provide the necessary support and fixation to ensure product stability during the welding process, and the positioning plate design allows for quick replacement or adjustment to adapt to different components or different welding requirements.

[0009] Preferably, two positioning bosses are provided at both ends of the upper surface of the welding positioning plate, respectively passing through two soft copper busbar welding positioning holes and two hard copper busbar welding positioning holes.

[0010] Furthermore, the width of the soldering piece is greater than the sum of the widths of the tooth-shaped portions of the soft and hard copper bars, so that one soldering piece can be adapted to the tooth-shaped portions of the soft and hard copper bars at the same time.

[0011] Preferably, after welding, the soft copper busbar and the hard copper busbar are respectively wrapped with a first mica tape insulation layer and a second mica tape insulation layer to improve insulation and heat resistance.

[0012] The beneficial effects of the present invention are as follows: the present welding structure enables the soft and hard copper bars to be interlocked through the toothed portion, and then the positioning boss on the positioning plate passes through the soft copper bar welding positioning hole and the hard copper bar welding positioning hole at the same time, which can ensure the accurate positioning of the soft and hard copper bar welding parts before welding, so as to reduce human errors and improve welding accuracy. The positioning plate can provide stable support and reduce the deformation of components caused by heat during the welding process. Reusing the positioning plate can ensure that the components to be welded each time are positioned and supported according to the same standards, ensuring the consistency of the connected products, reducing the time for adjustment and alignment, thereby improving production efficiency. At the same time, the use of the positioning plate can reduce the direct contact of the operator during the welding process and reduce safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0014] Figure 1 This is an exploded view of the soft and hard copper busbars and welding components in Example 1;

[0015] Figure 2 This is a schematic diagram of the coordination of the soft and hard copper busbars in Example 1;

[0016] Figure 3 Schematic diagram of the welding parts of the soft and hard copper bars in Example 1;

[0017] Figure 4 Schematic diagram of the coordination of the soft and hard copper busbars and soldering pieces in Example 1;

[0018] Figure 5 Schematic diagram of the welding state of the soft and hard copper busbars and welding components in Example 1;

[0019] Figure 6 This is a schematic diagram of the welding positioning plate in Example 1;

[0020] Figure 7 This is the cross section of the welding positioning plate at AA in Example 1;

[0021] In the figure, 1-copper busbar, 11-copper busbar welding positioning hole, 12-copper busbar toothed portion, 13-copper busbar processing step, 101-first mica tape insulation layer, 102-copper busbar welding portion;

[0022] 2-hard copper busbar, 21-hard copper busbar welding positioning hole, 22-hard copper busbar tooth-shaped portion, 23-hard copper busbar processing step, 201-second mica tape insulation layer, 202-hard copper busbar welding portion;

[0023] 3-welding positioning plate, 31-positioning boss; 4-welding piece, 5-resistance welding lower electrode, 6-resistance welding upper electrode. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two non-identical entities or non-identical parameters with the same name. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. Subsequent embodiments will not explain this one by one.

[0026] The directional and positional terms used in this invention, such as "upper," "lower," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are used solely to refer to the directions or positions in the accompanying drawings. Therefore, the directional and positional terms used are intended to illustrate and facilitate understanding of this invention and are not intended to limit the scope of protection of this invention.

[0027] Example 1

[0028] like Figure 1-7 As shown, the steps of an embodiment of applying the present welding structure are as follows:

[0029] Step 1: Prepare materials: Select 30 layers of 0.1mm copper foil and 0.1mm nickel sheets on the upper and lower sides as the raw materials for soft copper busbars, and 3mm thick hard copper busbars for product stamping. The purity of the materials is above 99.9% to ensure welding quality;

[0030] Step 2: Welding: Using polymer diffusion welding technology, 30 layers of 0.1mm copper foil and 0.1mm nickel sheets on the upper and lower sides are stacked and welded. The welding temperature is controlled at 680℃, the welding time is 60 seconds, and the welding pressure is 0.3MPa. This welding method does not require a large amount of solder and can ensure welding quality.

[0031] Step 3: Use the die stamping process to stamp the hard copper busbar to meet the required size of the product;

[0032] Step 4: Machining: Use CNC machining to process three V-grooves (soft copper bar tooth-shaped portion 12) and welding positioning holes φ3.2 (soft copper bar welding positioning holes 11) on the welded soft copper busbar. The V-groove depth is 5mm, the groove width is 5mm, the bottom groove width is 2mm, the angle is 33°, and the soft copper busbar processing step is 1.5mm thick. At the same time, a V-shaped convex groove (hard copper bar tooth-shaped portion 22) is punched on the 3mm thick hard copper busbar. The groove depth is 4.9mm, the groove width is 4.9mm, the bottom groove width is 1.9mm, and the angle is 33°. The hard copper busbar welding positioning holes are φ3.2mm, and the hard copper busbar processing step is 1.5mm.

[0033] Step 5: Use 1.5mmT2 copper to punch out a welding positioning plate. The positioning plate is punched to form a φ3mm positioning boss with a height of 0.8mm to facilitate the subsequent soft and hard copper bar resistor welding positioning;

[0034] Step 6: Welding: Use resistance welding technology to interlock the teeth of the soft copper busbar and the hard copper busbar, place them in the welding positioning plate 3, place the (Bag15CuP) 0.1mm solder piece 4 on the welding area of ​​the soft and hard copper busbars, use the upper and lower copper tungsten electrodes to weld the product, check and adjust the resistance welding parameters, start the welding power supply, and complete the product welding;

[0035] Step 7: In order to better improve the corrosion resistance of the product, the surface of the welded area of ​​the welded product is polished and smoothed; use mica tape to wrap it in layers, covering two-thirds of the product each time, and repeat in sequence until the required exposed size is reached. This type of product can withstand long-term high-temperature experiments. After the product is wrapped, it is insulated to meet the insulation resistance at high temperatures: above 500°C.

[0036] Step 8: After wrapping the mica tape, use PVC orange tape to wrap the soft and hard copper busbars again. After wrapping, use EOL testing equipment to test the product's insulation withstand voltage to meet the following performance requirements: 2800VDC, 60s, leakage current <1mA, etc.

[0037] In addition to employing a positioning plate to ensure welding accuracy and stability, the mica tape in the above setup has the following advantages:

[0038] 1. Insulation: Mica tape is used as an insulating material in new energy vehicles and can provide good electrical insulation performance. It is especially suitable for protecting copper or aluminum busbar connectors in power systems.

[0039] 2. Fire resistance: Mica tape contains soft mica and is used when fire resistance is required. It can maintain insulation performance at high temperatures.

[0040] 3. Lightweight: High-temperature resistant mica tape for new energy vehicles reduces the thickness of the mica layer, reducing the weight of the copper or aluminum busbar connectors, which helps to improve the driving range of new energy vehicles and optimize the battery cell layout;

[0041] 4. Reliability: Mica tape has been reinforced and designed with an insulation reinforcement layer to improve the tensile strength and fire resistance of the product, making it suitable for large-scale production and ensuring product quality. At the same time, mica can still maintain good insulation properties under the use environment of 500℃-1200℃, and has good bending strength and hardness, acid and alkali resistance, aging resistance, and does not produce toxic gases at high temperatures; using copper welding positioning plates to weld products can meet the applicability of the following products (for the design of mica tape, you can also refer to CN116013622A A high-temperature resistant mica tape and processing method for new energy vehicles).

[0042] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A soft and hard copper busbar welding structure, comprising a soft copper busbar (1) and a hard copper busbar (2), and a welding assembly, wherein the soft copper busbar (1) comprises a soft copper busbar welding portion (102) and a non-welding portion, and the hard copper busbar (2) comprises a hard copper busbar welding portion (202) and a non-welding portion; characterized in that: The soft copper bar welding portion (102) has a soft copper bar welding positioning hole (11) and a soft copper bar tooth-shaped portion (12), and the hard copper bar welding portion (202) has a hard copper bar welding positioning hole (21) and a hard copper bar tooth-shaped portion (22); the welding assembly includes a welding positioning plate (3) and a welding piece (4), and positioning bosses (31) are respectively provided at both ends of the welding positioning plate (3); The soft copper bar tooth-shaped portion (12) is engaged with the hard copper bar tooth-shaped portion (22); the soft copper bar welding positioning hole (11) and the hard copper bar welding positioning hole (21) are respectively positioned and matched with the positioning bosses (31) at both ends of the welding positioning plate (3); and the welding piece (4) is sandwiched between the soft and hard copper bar tooth-shaped portions and the welding positioning plate (3).

2. The soft and hard copper busbar welding structure according to claim 1, characterized in that: A soft copper bar processing step (13) is formed between the soft copper bar welding portion (102) and the non-welding portion, a hard copper bar processing step (23) is formed between the hard copper bar welding portion (202) and the non-welding portion, and the welding positioning plate (3) is embedded between the soft and hard copper bar processing steps.

3. The soft and hard copper busbar welding structure according to claim 2, characterized in that: The thickness of the soft copper busbar welding portion (102) and the hard copper busbar welding portion (202) are both smaller than the non-welding portion, and the thickness of the welding positioning plate (3) is adapted to the depth of the processing steps of the soft and hard copper busbars, so that the lower surface of the welding positioning plate (3) is flush with the lower surfaces of the soft copper busbar (1) and the hard copper busbar (2).

4. The soft and hard copper busbar welding structure according to claim 1, characterized in that: Two positioning bosses (31) are provided at both ends of the upper surface of the welding positioning plate (3), respectively passing through two soft copper busbar welding positioning holes (11) and two hard copper busbar welding positioning holes (21).

5. The soft and hard copper busbar welding structure according to claim 1, characterized in that: The width of the soldering piece (4) is greater than the sum of the widths of the tooth-shaped portions of the soft and hard copper bars, so that one soldering piece (4) can simultaneously fit the tooth-shaped portions of the soft and hard copper bars.

6. The soft and hard copper busbar welding structure according to claim 1, characterized in that: After welding, the soft copper busbar (1) and the hard copper busbar (2) are respectively wrapped with a first mica tape insulation layer (101) and a second mica tape insulation layer (201).

7. The soft and hard copper busbar welding structure according to claim 1, characterized in that: The welding assembly further comprises a resistance welding lower electrode (5) and a resistance welding upper electrode (6).

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