Welding needle for electric resistance welding

Abstract

The welding needle comprises a welding needle body, a sleeve and an elastic reset piece, the welding needle body comprises a welding head portion, a rod portion and a pressing top portion which are sequentially connected, the sleeve is of a hollow structure, a first opening is formed in the position, corresponding to the welding head portion, of the first end of the sleeve, and a second opening for the pressing top portion to penetrate out is formed in the second end of the sleeve. The sleeve is provided with a first clamping piece, and the elastic reset piece is arranged between the welding needle body and the sleeve. The welding needle has a first state during welding and a second state during non-welding, in the first state, the end face of the first end of the sleeve abuts against the welding face, and the welding needle body moves downwards and compresses the elastic reset piece till the outer end face of the welding head is flush with the end face of the first end. The closed cavity is formed among the welding needle body, the sleeve and the welding surface, so that the welding slag splashing range is only limited in the closed cavity even if explosion welding is generated during welding, and the cylindrical battery is effectively protected.

Description

Technical Field

[0001] This utility model relates to the field of batteries, and in particular to a welding needle for resistance welding. Background Technology

[0002] During the production and assembly of cylindrical batteries 2a, resistance welding is typically used to weld the tabs or current collectors 23a to the casing 21a. Figures 1 to 2 As shown, the specific process is as follows: 1. The core 22a prepared in the previous process is loaded into the housing 21a, which is usually a steel shell; 2. The steel shell containing the core 22a is transported to the spot welding base; 3. The welding needle 1a is inserted through the center hole 221a of the core 22a, and the lower end face of the welding needle 1a contacts the electrode tab or current collector 23a; 4. The welding head is pressed down to tighten the welding needle 1a, so that the welding head, welding needle 1a, electrode tab or current collector 23a, steel shell 21a and welding base form a conductive circuit; 5. The welding machine is powered on, so that the electrode tab or current collector 23a is welded together with the steel shell.

[0003] During resistance welding, weld spatter may occur at the interface between the electrode and the workpiece or between the workpieces. The shape of the currently used welding needle 1a is as follows: Figure 1 As stated, the welding needle 1a does not have the function of preventing welding explosions, and the welding slag and sparks 24a generated during welding explosions will fly everywhere, such as Figure 2 As shown, when the welding slag 24a splashes onto the diaphragm of the core 22a, it can cause the diaphragm to perforate, which in turn leads to excessive self-discharge and may even pose a safety risk. Summary of the Invention

[0004] The purpose of this invention is to provide a welding needle for resistance welding, so as to solve the problem of weld slag spatter causing damage to the welded parts during resistance welding in the prior art.

[0005] To achieve the above objectives, this utility model provides a resistance welding needle, comprising a needle body, a sleeve, and an elastic reset member. The needle body includes a welding head, a rod, and a pressing top connected in sequence. The sleeve has a hollow structure, with a first opening at the first end corresponding to the welding head and a second opening at the second end for the pressing top to pass through. A first snap-fit ​​member is provided on the sleeve, and the elastic reset member is disposed between the needle body and the sleeve. The welding needle has a first state during welding and a second state during non-welding. In the first state, the first end face of the sleeve presses against the welding surface, and the needle body moves down and compresses the elastic reset member until the outer end face of the welding head is flush with the first end face to form a closed cavity between the needle body, the sleeve, and the welding surface. In the second state, the elastic reset member resets and the welding needle snaps into place with the first snap-fit ​​member.

[0006] Preferably, the second end of the sleeve is provided with an end cap, the end cap is provided with a second opening, the cross-sectional dimension of the second opening is smaller than the cross-sectional dimension of the rod and the cross-sectional dimension of the pressing top is smaller than the cross-sectional dimension of the rod, so that the end cap forms the first snap-fit ​​member and the end cap snaps with the top end of the rod.

[0007] Preferably, the elastic reset member is a spring, the cross-sectional dimension of the welding head is smaller than the cross-sectional dimension of the rod to form a first step between the rod and the welding head, the sleeve is further provided with a second step corresponding to the first step, and the elastic reset member is disposed between the first step and the second step.

[0008] Preferably, the first end of the sleeve is provided with a contraction portion, the contraction portion including a frustum section and a straight section connected to the frustum section, the outer end face of the straight section being the first end face of the sleeve.

[0009] Preferably, the second step portion is located above the contraction portion, and the inner edge of the second step portion, the interior of the frustum section, and the interior of the straight section form a connecting hole with the same inner diameter.

[0010] Preferably, the sleeve is insulated from the welding needle body.

[0011] Preferably, the sleeve includes an upper sleeve portion and a lower sleeve portion, wherein the upper sleeve portion and the lower sleeve portion are threadedly connected.

[0012] Preferably, the upper cylinder portion includes a first main body portion and a first connecting section connected to the first main body portion, the first connecting section having an external thread; the lower cylinder portion includes a second main body portion and a second connecting section connected to the second main body portion, the second connecting section having an internal thread; the outer diameter of the second connecting section is the same as the outer diameter of the second main body portion and the first main body portion; the external thread and the internal thread are engaged and connected.

[0013] Preferably, the welding needle is used for a cylindrical battery, the cylindrical battery including a housing and a core disposed within the housing, the core including a central hole, the welding needle passing through the central hole and the welding head facing the bottom of the housing.

[0014] Compared with the prior art, this utility model sets a sleeve on the outside of the welding needle and forms a closed cavity between the welding needle body, the sleeve and the welding surface, thereby ensuring that even if welding explosion occurs during welding, the range of welding slag spatter is limited to the inside of the closed cavity, effectively protecting the welding components such as cylindrical batteries. Attached Figure Description

[0015] Figure 1 This is a structural diagram of a welding pin in the prior art;

[0016] Figure 2 This is a structural diagram of a welding needle used in the prior art to weld the casing and current collector of a cylindrical battery.

[0017] Figure 3 This is a structural diagram of the welding needle in an embodiment of the present invention.

[0018] Figure 4 for Figure 3 Enlarged view of point A in the middle.

[0019] Figure 5 for Figure 3 Enlarged view of point B in the middle.

[0020] Figure 6 This is a structural diagram of the second state of the welding needle used to weld the casing and current collector of a cylindrical battery according to an embodiment of the present invention.

[0021] Figure 7 This is a structural diagram of the first state of the welding needle used to weld the casing and current collector of a cylindrical battery according to an embodiment of the present invention.

[0022] Figure 8 for Figure 7 A magnified view of point C in the middle. Detailed Implementation

[0023] To explain in detail the technical content, structural features, and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0024] like Figures 3 to 8As shown, this utility model embodiment provides a resistance welding needle 10, including a welding needle body 1, a sleeve 2, and an elastic reset member 3. The welding needle body 1 includes a welding head 11, a rod 12, and a pressing top 13 connected in sequence. The sleeve 2 has a hollow structure, and the first end of the sleeve 2 is provided with a first opening 21 corresponding to the welding head 11. The second end of the sleeve 2 is provided with a second opening 22 for the pressing top 13 to pass through. The sleeve 2 is provided with a first snap-fit ​​member. The elastic reset member 3 is provided between the welding needle body 1 and the sleeve 2. The welding needle 10 has a first state during welding and a second state during non-welding. In the first state, the first end face of the sleeve 2 presses against the welding surface, and the welding needle body 1 moves down and compresses the elastic reset member 3 until the outer end face of the welding head 11 is flush with the first end face to form a closed cavity 5 between the welding needle body 1, the sleeve 2, and the welding surface. In the second state, the elastic reset member 3 is reset and the welding needle 10 is snapped with the first snap-fit ​​member. Specifically, the elastic reset member 3 is elastic and can be restored to its original position after being compressed. The welding needle body 1 can move up and down relative to the sleeve 2. During welding, the outer end face of the welding head 11 is flush with the first end face to form a closed cavity 5 between the welding needle body 1, the sleeve 2 and the welding surface. Therefore, even if welding explosion occurs during welding, the spatter 44 will only be confined to the inside of the closed cavity 5 and will not affect the components outside the welding surface, thus achieving protection for welding components such as the cylindrical battery 4.

[0025] This utility model embodiment provides a sleeve 2 outside the welding needle 10 and forms a closed cavity 5 between the welding needle body 1, the sleeve 2 and the welding surface, thereby ensuring that even if welding explosion occurs during welding, the spatter 44 will only be confined to the inside of the closed cavity, effectively protecting the welding components such as the cylindrical battery 4.

[0026] In this embodiment of the utility model, such as Figure 3 As shown, the second end of the sleeve 2 is provided with an end cap 23, and the end cap 23 is provided with a second opening 22. The cross-sectional dimension of the second opening 22 is smaller than the cross-sectional dimension of the rod 12, and the cross-sectional dimension of the pressing top 13 is smaller than the cross-sectional dimension of the rod 12, so that the end cap 23 forms a first snap-fit ​​and snaps with the top end of the rod 12. Specifically, the end cap 23 is integrally formed on the second end of the sleeve 2. By setting the end cap 23 as the first snap-fit ​​to limit the rising position of the welding needle body 1, the structure is simpler. Of course, in some other embodiments, the snap-fit ​​between the welding needle body 1 and the sleeve 2 can also be achieved by setting other protruding structures in the sleeve 2, which is not limited here.

[0027] In this embodiment of the invention, the elastic reset member 3 is a spring. The cross-sectional dimension of the welding head 11 is smaller than that of the rod 12, forming a first step 14 between the rod 12 and the welding head 11. A second step 25 is also provided inside the sleeve 2 corresponding to the first step 14. The elastic reset member 3 is located between the first step 14 and the second step 25. Specifically, the limiting of the elastic reset member 3 is achieved by providing a first step 14 on the welding needle body 1 and a second step 25 inside the sleeve 2, resulting in a simple structure and ingenious design. In some other embodiments, the elastic reset member 3 is not limited to a spring; it can also be a cylinder or a hydraulic cylinder, etc., selected according to actual needs.

[0028] In this embodiment of the utility model, such as Figures 3 to 4 As shown, the first end of the sleeve 2 is provided with a contraction section 24, which includes a frustum section 241 and a straight section 242 connected to the frustum section 241. The outer end face of the straight section 242 is the end face of the first end of the sleeve 2. Specifically, the contraction section 24 serves as a guide to facilitate the insertion of the welding needle 10 into the welding component, for example, to facilitate the insertion of the welding needle 10 into the center hole 421 of the core 42 of the cylindrical battery 4 to weld the current collector 43 to the bottom shell 411.

[0029] Furthermore, such as Figures 3 to 4 As shown, the second step portion 25 is located above the contraction portion 24. The inner edge of the second step portion 25, the interior of the frustum section 241, and the interior of the straight section 242 form a connecting hole with the same inner diameter. By forming a connecting hole with the same inner diameter on the inner edge of the second step portion 25, the interior of the frustum section 241, and the interior of the straight section 242, the structure is simple and easy to manufacture the sleeve 2.

[0030] In this embodiment of the utility model, the sleeve 2 and the welding needle body 1 are insulated from each other. Specifically, the sleeve 2 is made of a non-conductive material, such as Al2O3 ceramic, ZrO2 ceramic, or other ceramic materials. The sleeve 2 can also be made of thermosetting resins such as phenolic resin and polyimide. The welding needle body 1 is made of a metal or alloy material with good electrical and thermal conductivity, such as copper, chromium copper, tungsten copper, or ceramic particle dispersion reinforced copper.

[0031] In this embodiment of the utility model, such as Figure 3 as well as Figure 5As shown, the sleeve 2 includes an upper sleeve portion 201 and a lower sleeve portion 202, which are threadedly connected. Specifically, the upper sleeve portion 201 includes a first main body portion 2011 and a first connecting section 2012 connected to the first main body portion 2011. The first connecting section 2012 is provided with external threads. The lower sleeve portion 202 includes a second main body portion 2021 and a second connecting section 2022 connected to the second main body portion 2021. The second connecting section 2022 is provided with internal threads. The outer diameter of the second connecting section 2022 is the same as the outer diameter of the second main body portion 2021 and the first main body portion 2011. The external threads and internal threads are engaged for easy disassembly and replacement of the welding needle body 1 and the elastic reset component 3, etc.

[0032] In this embodiment of the utility model, such as Figures 3 to 8 As shown, the welding needle 10 is used for a cylindrical battery 4. The cylindrical battery 4 includes a housing 41 and a core 42 disposed within the housing 41. The core 42 includes a central hole 421. The welding needle 10 passes through the central hole 421 with its welding head 11 facing the bottom of the housing 41. Specifically, the housing 41 is usually a steel shell, and the bottom of the housing 41 is a bottom shell 411. The end of the core 42 is provided with a tab or current collector 43. The tab or current collector 43 has a welding surface, and the tab or current collector 43 can be welded to the bottom shell 411 of the housing 41 by the welding needle 10. During welding, the clamping sleeve 2 inserts the welding needle 10 as a whole into the core 42, and makes the lower end of the sleeve 2 fully press against the tab or current collector 43. The upper welding head presses down on the pressing top 13 of the welding needle body 1, so that the sleeve 2 and the welding needle body 1 are pressed together. When the spring is compressed, the bottom end of the welding needle body 1 moves downward to be flush with the bottom end of the sleeve 2. At this time, the welding machine is powered on, and a conductive circuit is formed between the welding head, welding needle 10, electrode tab or current collector 43, housing 41 and welding seat. A welding point is formed at the contact point between the electrode tab or current collector 43 and the bottom housing 411. Since a closed cavity 5 is formed between the sleeve 2 and the welding needle body 1, even if a welding explosion occurs, the spatter slag 44 is limited to the inside of the closed cavity 5 and cannot reach the core 42, thereby achieving the purpose of protecting the core 42.

[0033] The above-disclosed examples are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent changes made in accordance with the scope of the present utility model application shall still fall within the scope of the present utility model.

Claims

1. A resistance welding electrode characterized by comprising: The welding needle comprises a welding needle body, a sleeve and an elastic reset member, the welding needle body comprises a welding head, a rod and a pressing top connected in sequence, the sleeve is a hollow structure, a first opening is arranged on the first end of the sleeve corresponding to the welding head, a second opening is arranged on the second end of the sleeve for the pressing top to pass through, a first clamping member is arranged on the sleeve, and the elastic reset member is arranged between the welding needle body and the sleeve. The welding needle has a first state during welding and a second state during non-welding, in the first state, the first end face of the sleeve is pressed on the welding surface, the welding needle body moves downward and compresses the elastic reset member until the outer end face of the welding head is flush with the first end face to form a closed cavity between the welding needle body, the sleeve and the welding surface, in the second state, the elastic reset member resets and the welding needle is clamped with the first clamping member.

2. The resistance welding tip as set forth in claim 1, wherein The second end of the sleeve is provided with an end cover, the second opening is arranged on the end cover, the cross-sectional size of the second opening is smaller than the cross-sectional size of the rod and the cross-sectional size of the pressing top is smaller than the cross-sectional size of the rod, so that the end cover forms the first clamping member and the end cover is clamped with the top end of the rod.

3. The resistance welding tip as set forth in claim 1, wherein The elastic reset member is a spring, the cross-sectional size of the welding head is smaller than the cross-sectional size of the rod to form a first step between the rod and the welding head, the inside of the sleeve is also provided with a second step corresponding to the first step, and the elastic reset member is arranged between the first step and the second step.

4. The resistance welding tip as set forth in claim 3, wherein The first end of the sleeve is provided with a shrinkage part, the shrinkage part comprises a circular truncated cone segment and a straight segment connected with the circular truncated cone segment, and the outer end face of the straight segment is the first end face of the sleeve.

5. The resistance welding tip as set forth in claim 4, wherein The second step is arranged above the shrinkage part, the inner edge of the second step, the inside of the circular truncated cone segment and the inside of the straight segment form a communication hole with the same inner diameter.

6. The resistance welding tip as defined in claim 1, wherein The sleeve and the welding needle body are insulated.

7. The resistance welding tip as defined in claim 1, wherein The sleeve comprises an upper cylinder part and a lower cylinder part, and the upper cylinder part is threadedly connected with the lower cylinder part.

8. The resistance welding tip as set forth in claim 7, wherein The upper cylinder part comprises a first main body part and a first connecting segment connected with the first main body part, the first connecting segment is provided with external threads, the lower cylinder part comprises a second main body part and a second connecting segment connected with the second main body part, the second connecting segment is provided with internal threads, the outer diameter of the second connecting segment is the same as the outer diameters of the second main body part and the first main body part, and the external threads are connected with the internal threads in a matched mode.

9. The resistance welding tip of claim 1 wherein, The welding needle is used for a cylindrical battery, the cylindrical battery comprises a shell and a roll core arranged in the shell, the roll core comprises a center hole, the welding needle is arranged in the center hole and the welding head faces the bottom of the shell.

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