An output electrode welding method

Abstract

An output pole welding method is realized by structure size matching design to realize accurate assembly, a circular groove is arranged at the bottom of the copper column for placing the second soldering piece, a cylindrical pin is arranged at the bottom of the aluminum column, which can be accurately inserted and positioned with the assembly hole of the aluminum row, the first soldering piece is sleeved outside the cylindrical pin, and a double-layer solder structure is formed at the connection interface of the aluminum column and the aluminum row and the copper column and the aluminum column; after assembly is completed, high-frequency induction coil is used to synchronously surround the two groups of soldering piece areas for heating, so that the double-layer soldering piece is synchronously melted, and a dense and uniform double-layer soldering layer is formed after cooling, and the double-interface integrated welding is completed at one time. The structure positioning is accurate, the welding misplacement and virtual welding defects are effectively avoided, the welding quality consistency is greatly improved, the connection contact resistance is reduced, the heating problem under large current working condition is reduced, the welding process is simplified, the assembly and welding efficiency is improved, the output pole batch industrialized production of the power battery is adapted, and the practicality and reliability are stronger.

Description

Technical Field

[0001] This invention relates to the technology for connecting and processing the output electrodes of energy storage batteries and power batteries, specifically to a method for welding copper-aluminum composite output electrodes. Background Technology

[0002] The output electrodes of power batteries and energy storage modules generally adopt a composite structure of copper and aluminum pillars. Copper has excellent conductivity, while aluminum is lightweight and low in cost. The combination of the two takes into account both conductivity and weight reduction requirements. In production, the copper pillar, aluminum pillar, and aluminum busbar need to be reliably welded together for conductivity.

[0003] The existing copper-aluminum output electrode welding process has the following core defects:

[0004] Poor assembly positioning accuracy and lack of matching limit structure make it easy for aluminum pillars, copper pillars, aluminum bars, and brazing plates to shift or misalign during assembly. Uneven distribution of brazing filler metal during welding results in problems such as incomplete welding, missing welding, and inconsistent weld thickness.

[0005] When brazing filler metal is applied only in a single location, the brazing filler metal cannot be spread synchronously and evenly at the connection interfaces between the copper column and the aluminum column, and between the aluminum column and the aluminum busbar. This results in poor welding consistency at the two interfaces, large fluctuations in conductive contact resistance, and severe heat generation under high current conditions.

[0006] The welding heating method lacks targeted coating, and the induction coil cannot simultaneously and evenly heat the upper and lower brazing pieces. One brazing piece is fully melted while the other is under-melted, resulting in high weld strength dispersion and low product yield.

[0007] The parts lack matching dimensions and structures, and assembly relies on manual alignment, resulting in low assembly efficiency and high processing costs for mass production.

[0008] In summary, the existing output electrode welding structure has technical problems such as poor assembly positioning, inconsistent welding quality at the two interfaces, unstable conductivity, and low production efficiency. There is an urgent need to optimize the structural design to solve these problems. Summary of the Invention

[0009] To address the shortcomings of existing technologies, such as misalignment of copper and aluminum output electrodes, uneven brazing at the dual-connection interface, poor welding quality, severe conductive heating, and low assembly efficiency, an output electrode welding method is provided. By using a limiting matching structure and a double-layer brazing sheet layout in conjunction with high-frequency induction synchronous heating, precise positioning of copper pillars, aluminum pillars, and aluminum bars is achieved, along with synchronous and uniform brazing at both interfaces. This reduces contact resistance and improves welding strength and mass production yield.

[0010] To achieve the above and other related objectives, the technical solution provided by this invention is: an output electrode welding method, comprising the following steps:

[0011] Step 1: Prepare copper pillars, aluminum pillars, aluminum busbars, the first solder joint, and the second solder joint;

[0012] Step 2: Machining a groove at the bottom of the copper column, machining a pin at the bottom of the aluminum column, machining a hole on the aluminum busbar, machining the first brazing piece into an annular sheet structure, and machining the second brazing piece into a circular sheet structure;

[0013] Step 3: Fix the aluminum busbar horizontally, put the first brazing tab on the pin, insert the pin at the bottom of the aluminum column into the hole on the aluminum busbar, place the second brazing tab at the bottom of the groove at the bottom of the copper column, and fasten the copper column to the top of the aluminum column through the groove.

[0014] Step 4: Perform high-frequency induction welding on the positions of the first and second solder pieces.

[0015] The preferred technical solution is as follows: In step 2, the groove is a circular groove, the aluminum column is a cylindrical structure, and the inner diameter of the groove matches the outer diameter of the aluminum column.

[0016] A preferred technical solution is that, in step 2, the outer diameter of the second brazing piece matches the inner diameter of the groove.

[0017] A preferred technical solution is as follows: In step 2, the pin is a cylindrical structure, and the inner diameter of the first brazing tab matches the outer diameter of the pin.

[0018] The preferred technical solution is that, in step 2, the outer diameter of the first brazing tab matches the outer diameter of the aluminum pillar.

[0019] A preferred technical solution is that, in step 2, the diameter of the hole matches the outer diameter of the pin.

[0020] A preferred technical solution is that, in step 2, the depth of the hole matches the length of the pin.

[0021] The preferred technical solution is as follows: In step 4, the induction coil connected to the high-frequency induction welding machine is wrapped around the outside of the first and second brazing plates to achieve high-frequency induction welding.

[0022] Due to the application of the above technical solution, the beneficial effects of this invention are as follows:

[0023] Precise positioning eliminates assembly misalignment: all slots, pins, holes, and brazing tabs are designed with size matching, and automatic positioning is achieved during assembly, eliminating the need for repeated manual alignment and completely solving the problems of incomplete welding and missing welding caused by part misalignment, thus improving assembly efficiency.

[0024] Simultaneous and uniform brazing at dual interfaces significantly improves welding consistency: Two independent brazing plates are set up to correspond to two conductive connection interfaces respectively. With synchronous heating by a surrounding induction coil, the two brazing filler metals melt synchronously and uniformly, resulting in a uniform and stable weld layer thickness. This eliminates the defects of insufficient welding at single interfaces and reduces the dispersion of welding strength in batch products.

[0025] Reduce contact resistance and suppress high current heating: Both connection interfaces form a complete and continuous brazing layer with sufficient conductive contact area and minimal interface gap. The overall contact resistance of the output electrode is significantly reduced, and the temperature rise of the power battery under high current charging and discharging conditions is significantly reduced, thus improving the operational safety of the module.

[0026] Simplify processes and reduce production costs: Two welding points can be completed with one clamping and one induction heating, eliminating the need for secondary positioning and secondary welding processes, shortening the processing time per piece, adapting to automated mass production lines, and effectively reducing labor and equipment energy costs.

[0027] The structure is simple and reliable with strong versatility: all parts are standard cylindrical, ring, and circular structures, which are easy to process, adaptable to different specifications of power output poles, and have good interchangeability of parts. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the output electrode structure involved in the present invention.

[0029] Figure 2 This is a schematic diagram of the output pole cross-section involved in the present invention.

[0030] Figure 3 The present invention relates to an output electrode welding method. Detailed Implementation

[0031] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0032] Please see Figures 1-3It should be noted that in the description of this invention, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. The terms "horizontal," "vertical," and "suspended," etc., do not indicate that the component must be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] Example:

[0035] like Figures 1 to 3 As shown, according to an overall technical concept of the present invention, an output electrode welding method is provided, comprising the following steps:

[0036] Step 1: Prepare copper pillar 1, aluminum pillar 2, aluminum busbar 3, first solder joint (not shown) and second solder joint (not shown);

[0037] Step 2: Machining groove 11 at the bottom of copper column 1, machining pin 21 at the bottom of aluminum column 2, machining hole 31 on aluminum strip 3, machining the first brazing piece into an annular plate structure, and machining the second brazing piece into a circular plate structure.

[0038] Step 3: Fix the aluminum busbar 3 horizontally, put the first brazing tab on the pin 21, insert the pin 21 at the bottom of the aluminum column 2 into the hole 31 on the aluminum busbar 3, place the second brazing tab at the bottom of the groove 11 at the bottom of the copper column 1, and fasten the copper column 1 to the top of the aluminum column 2 through the groove 11.

[0039] Step 4: Perform high-frequency induction welding on the positions of the first and second solder pieces.

[0040] Specifically, a circular groove 11 is machined at the lower end of the copper column 1, and the inner diameter of the circular groove 11 is clearance-fitted with the outer diameter of the aluminum column 2; the outer diameter of the second brazing die is equal to the inner diameter of the circular groove 11, and it is laid at the bottom of the circular groove 11.

[0041] A cylindrical pin 21 is integrally machined at the lower end of the aluminum column 2. A circular assembly hole 31 is opened on the aluminum strip 3. The diameter of the assembly hole 31 matches the outer diameter of the cylindrical pin 21, and the depth of the assembly hole 31 is consistent with the length of the cylindrical pin 21. The first brazing piece is annular, with the inner diameter fitting the outer diameter of the cylindrical pin 21, and the outer diameter of the annular circle is equal to the outer diameter of the main body of the aluminum column 2.

[0042] Assembly process:

[0043] Fix the aluminum busbar 3 horizontally using the tooling.

[0044] Insert the first brazing piece into the cylindrical pin 21 from the lower end of the aluminum pillar 2 until it fits against the lower end face of the aluminum pillar 2.

[0045] The cylindrical pin 21 of the aluminum column 2 is vertically inserted into the assembly hole 31 of the aluminum strip 3, and the radial and axial positioning of the aluminum column 2 is achieved by the cooperation of the pin 21 and the hole 31.

[0046] The second brazing piece is laid flat in the circular groove 11 at the bottom of the copper column 1, and then the copper column 1 is fastened to the top of the aluminum column 2 from top to bottom. The inner wall of the circular groove 11 wraps the outer wall of the upper end of the aluminum column 2, and the second brazing piece is pressed between the bottom of the groove 11 of the copper column 1 and the upper end face of the aluminum column 2.

[0047] The induction coil of the high-frequency induction welding machine is wrapped around the area where the first and second brazing plates are located. The welding machine is started to heat up simultaneously, and the two brazing plates melt at the same time. After cooling, two dense brazing layers are formed, completing the integrated welding of the output electrode.

[0048] In this embodiment, the brazing filler metal is a copper-aluminum composite filler metal, and the induction coil adopts a ring coaxial winding structure, which can simultaneously and uniformly output heat energy to the upper and lower brazing areas, and the dual-interface melting synchronization is good.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for welding output electrodes, characterized in that, Includes the following steps: Step 1: Prepare copper pillars, aluminum pillars, aluminum busbars, the first solder joint, and the second solder joint; Step 2: Machining a groove at the bottom of the copper column, machining a pin at the bottom of the aluminum column, machining a hole on the aluminum busbar, machining the first brazing piece into an annular sheet structure, and machining the second brazing piece into a circular sheet structure; Step 3: Fix the aluminum busbar horizontally, put the first brazing tab on the pin, insert the pin at the bottom of the aluminum column into the hole on the aluminum busbar, place the second brazing tab at the bottom of the groove at the bottom of the copper column, and fasten the copper column to the top of the aluminum column through the groove. Step 4: Perform high-frequency induction welding on the positions of the first and second solder pieces.

2. The output electrode welding method according to claim 1, characterized in that: In step 2, the groove is a circular groove, the aluminum column is a cylindrical structure, and the inner diameter of the groove matches the outer diameter of the aluminum column.

3. The output electrode welding method according to claim 1, characterized in that: In step 2, the outer diameter of the second brazing tab matches the inner diameter of the groove.

4. The output electrode welding method according to claim 1, characterized in that: In step 2, the pin is a cylindrical structure, and the inner diameter of the first brazing tab matches the outer diameter of the pin.

5. The output electrode welding method according to claim 1, characterized in that: In step 2, the outer diameter of the first brazing tab matches the outer diameter of the aluminum pillar.

6. The output electrode welding method according to claim 1, characterized in that: In step 2, the diameter of the hole matches the outer diameter of the pin.

7. The output electrode welding method according to claim 1, characterized in that: In step 2, the depth of the hole matches the length of the pin.

8. The output electrode welding method according to claim 1, characterized in that: In step 4, an induction coil connected to a high-frequency induction welding machine is wrapped around the outside of the first and second brazing plates to achieve high-frequency induction welding.

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