Battery inner pole post cross-bridge welding structure and auxiliary jig thereof

Abstract

The application discloses a battery inner pole post cross-bridge welding structure and an auxiliary jig thereof, which is characterized in that a groove is arranged at the top of the inner pole post, and a secondary step is arranged below the groove; when two stepped inner pole posts are butted, an inner pole post whole is formed; through the above structure, a T-shaped solder storage groove is formed between the two combined inner pole posts; a special welding clamp is matched; the inner pole post support die is arranged on the welding clamp; the opening and closing of the inner pole post support die can effectively realize the support between the bottom surface of the secondary step and the middle partition plate through the bottom die; when welding, gaps are arranged between the outer diameter of the inner pole post and the inner wall of the counterbore and between the two inner pole posts supported by the bottom die; the existence of the two gaps can make the welding gun flame enter the inner pole post, make the inner and outer welding temperatures uniform, and make the welding effect optimal.

Description

Technical Field

[0001] This invention belongs to the field of battery assembly technology, and in particular relates to a battery internal electrode bridge welding structure and its auxiliary fixture. Background Technology

[0002] In recent years, with the rapid development of new energy technologies, the application fields of lead-acid batteries have been continuously expanding, and the demand has increased significantly. The demand for batteries of various specifications and models, such as those used in electric vehicles, UPS backup power supplies, and GFM series batteries, is constantly increasing. The bridge structure between individual cells within the battery plays a crucial role in current transmission and battery life. Currently, besides through-wall welding, the internal electrode post bridge welding structure has many problems, mainly manifested in: small welding contact area (the conventional bridge welding depth is about 4-5mm), small contact area, high resistance at the welding point, becoming a bottleneck for current conduction, easily causing localized high temperatures and melting, leading to battery failure, and even failing to meet 3C discharge requirements. To address the shortcomings of existing technology and achieve 3C discharge requirements, the industry currently usually increases the welding area by increasing the diameter of the internal electrode post and the size of the bridge clamp, etc. However, this improvement method cannot fundamentally solve the problem of localized high temperatures caused by the welding area being smaller than the electrode post area. Therefore, this technical change also has quality risks and further increases the cost by about 30%, resulting in waste. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a battery internal terminal bridge welding structure and its auxiliary fixture. By using the bridge welding auxiliary fixture and the corresponding welding method, the welding depth is increased, the contact area at the welding point is increased, the heat generated by current conduction is balanced, and the battery life is improved.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A battery inner electrode bridge welding structure and its auxiliary fixture are disclosed. Each busbar has a stepped inner electrode. The top of the stepped inner electrode has a bevel, and below the bevel is a secondary step. When two stepped inner electrodes are joined together, they form a single inner electrode. A gap width A is formed inside the inner electrode, which is 7-10 mm. The distance B between the bottom surface of the secondary step and the inner separator is 3-5 mm.

[0006] A gap C is provided between the inner pole post and the side of the inner partition plate of the shell, wherein C is a gap of 1.5 to 2 mm for filling with sealant;

[0007] A welding clamp is used in conjunction with the stepped inner pole. The end of the welding clamp is provided with an openable inner pole support mold. The inner pole support mold consists of two support mold bodies, which are welded to the jaws of the welding clamp. The welding clamp can be closed by the movement of the jaws. The interior of each inner pole support mold is provided with a half countersunk hole. Each half countersunk hole is provided with a bottom through hole. A bottom mold is designed to divide the bottom through hole in two. The bottom through hole is used to allow the inner pole to pass through vertically. The bottom mold is used to provide support between the bottom surface of the secondary step and the middle partition. A blocking edge is provided at the bottom of the countersunk hole to prevent the solder from seeping down.

[0008] After the inner electrode post penetrates the countersunk hole, a welding gap is provided between the outer diameter of the inner electrode post and the inner wall of the countersunk hole.

[0009] The welding clamp consists of three parts, including a hinged clamp handle, an arc-shaped block on the jaws at the front end of the clamp handle, and the arc-shaped block connecting the inner pole support mold and the jaws as one unit. The angle D after the clamp handle and the inner pole support mold are combined is between 120 and 145 degrees.

[0010] The inner pole support mold is made of high-temperature resistant metal.

[0011] The present invention has the following beneficial effects: Through the above design, the present invention has a bevel at the top of the inner pole post and a secondary step below the bevel. When the two stepped inner pole posts are joined together, they form a whole inner pole post. Through the above structural design, a T-shaped solder storage tank can be formed between the two. With this structural design, and in conjunction with a specially made welding clamp, the welding clamp is equipped with an inner pole post support mold. By opening and closing the inner pole post support mold, the bottom mold can effectively support the bottom surface of the secondary step to the middle partition. During welding, there is a gap between the outer diameter of the inner pole post and the inner wall of the countersunk hole, and there is also a gap between the two inner pole posts through the bottom mold support. The simultaneous existence of the two gaps allows the welding torch flame to enter the interior, making the internal and external welding temperatures uniform and achieving the best welding effect.

[0012] Through the above design scheme, the improved battery cluster inner electrode bridge welding structure overcomes the inherent characteristics of the traditional oblique welding structure. With the above structure and the cooperation of the equipment, the two inner electrode columns are fused into one in the mold cavity to achieve a complete fusion state and ensure the required welding surface requirements. Furthermore, due to the design of the mold size, there is a gap for sealant between the inner electrode column, the inner separator and the shell sealing groove, which can seal firmly and prevent air leakage. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0014] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0015] Figure 2 This is a top view of the structure of the present invention;

[0016] Figure 3 This is a schematic diagram of the mating structure between the inner pole post and the inner pole post support mold of the present invention;

[0017] Figure 4 This is a schematic diagram of the three-dimensional structure of the welding clamp proposed in this invention.

[0018] Figure 5 This is a schematic diagram of the connection structure between the inner pole and the housing sealing groove in the present invention.

[0019] Figure 6 This is a schematic diagram showing the overall joining angle of the welding clamps;

[0020] In the diagram, 1. Battery casing, 2. Cluster, 3. Busbar, 4. Inner pole, 5. Welding clamp, 6. Clamp handle, 7. Arc-shaped block, 8. Inner pole support mold, 81. Support mold body, 82. Countersunk hole, 83. Bottom mold, 84. Blocking edge, 85. Bottom through hole, 9. Inner partition, 10. Welding gap, 11. Bevel, 12. Secondary step, 13. Middle welding gap, 14. Casing sealing groove. Detailed Implementation

[0021] The present invention will be further described below through embodiments.

[0022] A battery internal electrode bridge welding structure and its auxiliary fixture, such as Figure 1 and Figure 2 As shown, the battery casing 1 has multiple clusters inside, and each cluster 2 has a busbar 3 on top. As shown in the figure, each busbar 3 has an inner electrode post 4. The solution proposed here is about the welding of the inner electrode post.

[0023] Before the improvement, during welding, two gaps ≥2mm appeared at the bottom of the inner electrode 4, resulting in surface fusion and a false weld at the root (the larger the allowance, the deeper the false weld). This internal defect was difficult to detect and seriously affected the welding quality. The main reason for this situation is that when the flame first contacts the top surface of the inner electrode 4, the surface lead layer melts instantly, flows, and fills the mold gaps. Because the temperature of the deeper parts of the lead and the mold is relatively low (the mold temperature must always be ≤100°C), the filled part of the molten lead cools down and separates from the workpieces on both sides. As the welding time increases, the upper part of the lead gradually melts and fuses completely. The main reason is that the top and bottom of the inner electrode are heated at different times and at different temperatures.

[0024] The improvement techniques in this solution are as follows:

[0025] The stepped inner pole post 4 has a bevel 11 at the top and a secondary step 12 below the bevel 11. When two inner pole posts 4 are joined together, they form a cylindrical inner pole post. The gap width A formed inside the inner pole post 4 is 7-10 mm, with 9 mm being optimal. The distance B between the bottom surface of the secondary step and the inner partition 9 is 3-5 mm, with 4 mm being optimal.

[0026] Furthermore, such as Figure 5 As shown, a gap C is provided between the inner pole post 4 and the side of the inner partition plate 9 of the housing. The gap C is 1.5 to 2 mm and is used for filling with sealant, with 2 mm being the optimal size.

[0027] The above technologies improve the internal pole structure; the following are improvements to the welding auxiliary fixture:

[0028] A welding clamp 5 is used in conjunction with the stepped inner pole 4. The end of the welding clamp 5 is provided with an openable inner pole support mold 8. The inner pole support mold is made of high-temperature resistant metal. The inner pole support mold 8 is composed of two support mold bodies 81, which are welded to the jaws of the welding clamp 5. The welding clamp can be closed by the action of the clamp handle 6. The interior of the inner pole support mold 8 is provided with a half countersunk hole 82. Each half countersunk hole 82 is provided with a bottom through hole 85. A bottom mold 83 divides the bottom through hole 85 into two parts. The bottom through hole 85 is used to allow the inner pole to pass through vertically. The bottom mold 83 is used to support the area between the bottom surface of the secondary step and the middle partition. A blocking edge 84 is provided at the bottom of the countersunk hole 82. The blocking edge 84 is used to prevent the upper solder from penetrating downward. The area above the blocking edge forms a welding gap 10 during welding, and a solder pool is formed through the welding gap 10.

[0029] To facilitate operation, the welding clamp 5 consists of three parts, including a hinged clamp handle 6, an arc-shaped block 7 on the jaws at the front end of the clamp handle 6, and the arc-shaped block 7 connecting the inner pole support mold 8 to the jaws as a single unit. Figure 6 As shown, the angle between the clamp handle 6 and the inner pole support mold 8 is between 120 and 145 degrees, with 135 degrees being the optimal angle. This structural design makes it easier for personnel to operate the clamp by hand.

[0030] In operation, this invention employs a stepped transition at the inner electrode joint, creating a second step 12 4mm from the bottom of the middle partition plate (i.e., dimension B), and increasing the joint width A to 9mm. Before welding, the inner electrode is clamped and fixed using welding clamps 5, forming a T-shaped solder storage groove between the two. The welding clamps 5 are equipped with an inner electrode support mold 8. By opening and closing the inner electrode support mold 8, the bottom mold 83 can be effectively used to support the bottom surface of the second step to the middle partition plate. During welding, a gap is provided between the outer diameter of the inner pole and the inner wall of the countersunk hole 82, and a central welding gap 13 is also provided between the two inner poles through the bottom mold 83 support. The simultaneous existence of these two gaps allows the welding torch flame to enter the interior, ensuring uniform welding temperature inside and outside. The flame can fully penetrate the 9mm space, instantly melting the bottom lead material. Then, as the lead around the flame melts, it continuously flows into the central molten pool and fills it, forming a cylindrical melting point with a depth ≥7mm that fills the solder storage tank of the T-shaped structure. This invention overcomes the phenomenon of incomplete penetration at the root of traditional welding. Different flame sizes can be adjusted according to different needs to achieve welding depths and different welding areas.

[0031] Through the above design scheme, the improved battery cluster inner electrode bridge welding structure overcomes the inherent characteristics of the traditional oblique welding structure. Through the above structure and the cooperation of the equipment, the two inner electrode columns are fused into one in the mold cavity to achieve a complete fusion state and ensure the required welding surface requirements. Furthermore, due to the design of the mold size, there is a gap for sealant between the inner electrode column, the inner partition and the shell sealing groove 14, which can seal firmly and prevent air leakage.

Claims

1. A battery internal electrode bridge welding structure and its auxiliary fixture, wherein a stepped internal electrode is provided on each busbar, characterized in that: The top of the stepped inner pole column is provided with a bevel, and a secondary step is provided below the bevel. When the two stepped inner pole columns are joined together, they form a whole inner pole column. A gap width A is formed inside the inner pole column, and the gap width A is 7-10mm. The distance B between the bottom surface of the secondary step and the inner partition is 3-5mm. A gap C is provided between the inner pole post and the side of the inner partition plate of the shell, wherein C is a gap of 1.5 to 2 mm for filling with sealant; A welding clamp is used in conjunction with the stepped inner pole. The end of the welding clamp is equipped with an openable inner pole support mold. The inner pole support mold consists of two support mold bodies, which are welded to the jaws of the welding clamp. The welding clamp can be closed by the movement of the jaws. The interior of each inner pole support mold is provided with a half countersunk hole. Each half countersunk hole is provided with a bottom through hole. A bottom mold is designed to divide the bottom through hole in two. The bottom through hole is used to allow the inner pole to pass through vertically. The bottom mold is used to provide support between the bottom surface of the secondary step and the middle partition. A blocking edge is provided at the bottom of the countersunk hole to prevent the solder from seeping down. After the inner electrode post penetrates the countersunk hole, a welding gap is provided between the outer diameter of the inner electrode post and the inner wall of the countersunk hole.

2. The battery internal electrode bridge welding structure and its auxiliary fixture as described in claim 1, characterized in that: The welding clamp consists of three parts, including a hinged clamp handle, an arc-shaped block on the jaws at the front end of the clamp handle, and the arc-shaped block connecting the inner pole support mold and the jaws as one unit. The angle D after the clamp handle and the inner pole support mold are combined is between 120 and 145 degrees.

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