Welding structure of power battery

Abstract

The utility model discloses a welding structure of a power battery, which comprises an insulating spacer and a flat head welding pin, the insulating spacer comprises an insulating body, the middle part of the insulating body is provided with a middle through hole, and the inner wall of the middle through hole is uniformly provided with a plurality of elastic sheets along the circumferential direction; the elastic pieces extend downwards from the inner wall of the middle through hole to form a horn shape, the free ends of the elastic pieces define a penetrating hole part, and the penetrating hole part is used for allowing the flat-head welding needle to penetrate through and abuts against the rod part of the flat-head welding needle so that the flat-head welding needle can be vertically arranged. According to the utility model, the insulating spacer is arranged, and the plurality of elastic sheets abutted against the rod part of the flat-end welding needle are arranged in the middle of the insulating spacer, so that the flat-end welding needle is self-adaptively rectified when the flat-end welding needle passes through the perforation part, the welding area is larger, the welding effect is good, and the welding quality is improved. And the problems of pseudo soldering or explosion and the like of the power battery are effectively avoided.

Description

Technical Field

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

[0002] Currently, lithium-ion or sodium-ion cylindrical batteries are gradually becoming the mainstream products in the new energy industry due to their advantages such as high energy density, good capacity consistency, and ability to support high-rate charging and discharging. More and more manufacturers are continuously pursuing high stability and high production capacity of cylindrical battery electrical performance. Common issues include:

[0003] 1. To increase production capacity, cylindrical power batteries generally prefer a resistance welding structure between the bottom of the casing and the current collector. However, automated lines usually insert the pins first and then weld them one by one. The welding pins are generally not perpendicular to the bottom of the casing, so only round-headed welding pins can be used. The welding area is small. When the vehicle is installed and vibrates, the large bare cells inside jump and directly impact the welding position, which can easily cause them to fall off, resulting in the risk of open circuit failure of the battery.

[0004] 2. The round-headed welding needle has a small welding area, which cannot meet the needs of high-rate charging and discharging of power batteries, or the small resistance welding area leads to a large temperature rise in the battery, posing a safety risk to the battery.

[0005] 3. Resistance welding needles pass through the center hole of the bare battery cell for bottom resistance welding. Generally, the diameter of the welding needle is much smaller than the diameter of the center hole, which means that the welding needle is easy to tilt inside the hole. The flat-head structure welding needle and the current collector need to be welded in a nearly perpendicular state, otherwise problems such as incomplete welding or explosion may occur. Summary of the Invention

[0006] The purpose of this utility model is to provide a welding structure for power batteries to solve the problems in the prior art where the flat-head welding needle is tilted in the center hole of the power battery, resulting in incomplete welding or explosion.

[0007] To achieve the above objectives, this utility model provides a welding structure for a power battery, including an insulating gasket and a flat-headed welding needle. The insulating gasket includes an insulating body with a central through hole in the middle. A plurality of spring pieces are evenly distributed circumferentially on the inner wall of the central through hole. Each of the spring pieces extends downward from the inner wall of the central through hole and forms a trumpet shape. The free ends of the spring pieces form a through hole, which is used to pass through the flat-headed welding needle and abut against the rod of the flat-headed welding needle so that the flat-headed welding needle is vertically positioned.

[0008] Preferably, the spring sheet gradually contracts in the direction away from the central through hole so that a gap is formed between two adjacent spring sheets.

[0009] Preferably, the insulating body is further provided with a strip-shaped through groove and several seepage holes.

[0010] Preferably, the power battery further includes a housing and bare cells disposed within the housing, wherein the bare cells have a central hole in the middle, and the central through hole is correspondingly disposed to the central hole.

[0011] Preferably, the power battery includes a first current collector, the insulating pad is disposed on the first current collector, and the edge of the insulating pad is bonded to the edge of the bare cell by insulating tape.

[0012] Preferably, the first collector plate includes a collector body and an extension handle extending outward from the collector body, the extension handle being bent towards the upper part of the collector body and passing through the strip-shaped through groove.

[0013] Preferably, one side of the bare battery cell is welded to the first current collector, and the other side of the bare battery cell is welded to the second current collector. The flat-head welding needle includes the rod and a welding head at one end of the rod. The flat-head welding needle passes through the through hole and the central hole, and the welding head presses against the middle of the second current collector to weld the second current collector to the housing.

[0014] Preferably, the cross-sectional dimension of the welding head is smaller than the cross-sectional dimension of the rod.

[0015] Preferably, the insulating pad is made of plastic.

[0016] Preferably, the perforated portion is circular and the diameter of the perforated portion is a first diameter, the diameter of the shank of the flat-headed welding needle is a second diameter, and the difference between the first diameter and the second diameter is greater than or equal to -0.1 mm and less than or equal to 0.1 mm.

[0017] Compared with the prior art, this utility model sets an insulating pad and sets several spring pieces in the middle of the insulating pad that abut against the flat-head welding needle rod. This allows the flat-head welding needle to self-correct as it passes through the perforation part, resulting in a larger welding area, better welding effect, and effectively avoiding problems such as poor welding or explosion in the power battery. Attached Figure Description

[0018] Figure 1 This is a structural diagram of the welding structure of the power battery according to an embodiment of the present invention.

[0019] Figure 2 This is a structural diagram of the insulating gasket in the welding structure of the power battery according to an embodiment of the present invention, taken at one angle.

[0020] Figure 3 This is a structural diagram of the insulating gasket in the welding structure of the power battery according to an embodiment of the present invention, taken from another angle.

[0021] Figure 4 for Figure 1 Cross-sectional structural diagram.

[0022] Figure 5 for Figure 4 Enlarged view of point A 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 1 to 5 As shown, this embodiment of the utility model provides a welding structure for a power battery, including an insulating gasket 4 and a flat-headed welding needle 5. The insulating gasket 4 includes an insulating body 41, with a central through hole 42 in the middle. A plurality of elastic pieces 43 are evenly distributed circumferentially along the inner wall of the central through hole 42. Each elastic piece 43 extends downward from the inner wall of the central through hole 42 and forms a trumpet shape. The free ends of the elastic pieces 43 form a through hole 431, which is used to insert the flat-headed welding needle 5 and abut against the rod 51 of the flat-headed welding needle 5 to ensure the flat-headed welding needle 5 is vertically positioned. Specifically, the insulating gasket 4 is made of plastic, such as PP or PET. The insulating gasket 4 can be integrally molded by injection molding or punched from a plastic sheet. The plastic insulating gasket 4 effectively ensures the elastic performance of the elastic pieces 43. The power battery can be a cylindrical power battery, which also includes a housing 1 and bare cells 2 disposed within the housing 1. The bare cells 2 have a central hole 21 in the middle, and a central through hole 42 is correspondingly disposed with the central hole 21. One side of the bare cells 2 is welded to the first current collector 3, and the other side of the bare cells 2 is welded to the second current collector 6. The flat-head welding needle 5 includes a rod 51 and a welding head 52 disposed at one end of the rod 51. The flat-head welding needle 5 passes through the through hole 431 and the central hole 21, and the welding head 52 presses against the middle of the second current collector 6 to weld the second current collector 6 to the housing 1. By setting a spring piece 43 in the central through hole 42, when the flat-headed welding needle 5 passes through the through hole 431, if the position of the flat-headed welding needle 5 is not vertical and there is a positioning eccentricity, the elasticity of the spring piece 43 can adaptively correct and limit the flat-headed welding needle 5. When the height of the flat-headed welding needle 5 drops by more than half, it maintains a vertical descent under the action of the center of gravity, so that the head of the flat-headed welding needle 5 makes vertical contact with the second collector plate 6, with a large contact area, thereby making the welding area larger and the welding effect better.

[0025] This utility model embodiment sets an insulating pad 4 and sets several spring pieces 43 in the middle of the insulating pad 4 that abut against the rod part 51 of the flat-head welding needle 5. This allows the flat-head welding needle 5 to self-correct as it passes through the through hole 431, resulting in a larger welding area, better welding effect, and effectively avoiding problems such as poor welding or explosion in the power battery.

[0026] In this embodiment of the utility model, the spring piece 43 gradually contracts in the direction away from the central through hole 42 so that a gap is formed between two adjacent spring pieces 43. Specifically, the ends of adjacent spring pieces 43 connected to the central through hole 42 are in contact with each other, and the spring piece 43 gradually contracts in the direction away from the central through hole 42, thereby forming a gap between adjacent spring pieces 43 and forming a petal-like structure, thus ensuring the density of the spring pieces 43 and making the spring piece 43 have a better correction and limiting effect on the flat-head welding needle 5.

[0027] Furthermore, the insulating body 41 is also provided with a strip-shaped through groove 44 and several seepage holes 45. Specifically, the strip-shaped through groove 44 and several seepage holes 45 are evenly arranged around the central through hole 42. The first current collector 3 includes a current collector body 31 and an extension handle 32 extending outward from the current collector body 31. The extension handle 32 is bent towards the upper part of the current collector body 31 and passes through the strip-shaped through groove 44. Specifically, the current collector body 31 is used for welding to the tab on one side of the bare cell 2, and the extension handle 32 is used for connecting to the cover of the power battery.

[0028] In this embodiment of the invention, the power battery includes a first current collector 3, and an insulating pad 4 is disposed on the first current collector 3, with the edge of the insulating pad 4 bonded to the edge of the bare cell 2 by insulating tape. Specifically, the insulating pad 4 is bonded and fixed to the edge of the bare cell 2 by insulating tape. After welding is completed, the insulating tape can be removed, making it very convenient to use.

[0029] Furthermore, one side of the bare cell 2 is welded to the first current collector 3, and the other side of the bare cell 2 is welded to the second current collector 6. The flat-head welding needle 5 includes a rod 51 and a welding head 52 located at one end of the rod 51. The flat-head welding needle 5 passes through the through hole 431 and the central hole 21, and the welding head 52 presses against the middle of the second current collector 6 to weld the second current collector 6 to the housing 1. Specifically, the end of the welding head 52 has a planar structure to ensure a large contact area between the welding head 52 and the second current collector 6.

[0030] In this embodiment of the invention, the cross-sectional dimension of the welding head 52 is smaller than that of the rod 51, ensuring that when the welding head 52 passes through the through hole 431, the through hole 431 has no effect on the welding head 52.

[0031] In this embodiment of the utility model, the perforated part 431 is circular and the diameter of the perforated part 431 is the first diameter D, and the diameter of the rod part 51 of the flat-head welding needle 5 is the second diameter d1. The difference between the first diameter D and the second diameter d1 is greater than or equal to -0.1 mm and less than or equal to 0.1 mm.

[0032] The assembly method of the welding structure of the power battery of this utility model is as follows: First, the two full-pole tabs on both sides of the bare cell 2 are laser welded to the first current collector 3 and the second current collector 6 respectively; then, the extension shank 32 of the first current collector 3 is passed through the strip groove 44 of the insulating pad 4; then, a ring of insulating tape is attached to the edge of the insulating pad 4 and the bare cell 2 to fix the insulating pad 4 and the bare cell 2; and the bare cell 2 with the first current collector 3, the second current collector 6 and the insulating pad 4 installed is placed in the housing 1, with the insulating pad 4 facing the housing. In the direction of the opening; when the flat-head welding needle 5 passes through the perforation part 431, if there is a positioning eccentricity, the elasticity of the spring piece 43 can adaptively correct and limit the flat-head welding needle 5. When the height of the flat-head welding needle 5 drops by more than half, under the effect of the center of gravity sinking, the appearance of the vertical current collector plate continues to drop. The head of the flat-head welding needle 5 maintains vertical contact with the second current collector plate 6. Then, the welding equipment presses down on the tail of the flat-head welding needle 5, and the flat-head welding needle 5 performs resistance welding on the second current collector plate 6 and the bottom 11 of the shell 1. After the welding is completed, the tail of the welding needle is clamped and taken out.

[0033] This embodiment of the invention arranges petal-shaped spring pieces 43 circumferentially on the inner wall of the through hole 42 in the middle of the insulating pad 4, and uses a flat-headed welding needle 5. This achieves that the diameter of the rod 51 of the flat-headed welding needle 5 is similar to the diameter of the through hole 431. When the flat-headed welding needle 5 passes through the through hole 431, if there is a positioning eccentricity in the relative position, the elastic spring piece 43 can adaptively correct and limit the flat-headed welding needle 5. When the height of the flat-headed welding needle 5 drops by more than half, it continues to descend vertically under the effect of the center of gravity, and the head of the flat-headed welding needle 5 makes vertical contact with the second current collector 6. The welding equipment presses down the tail of the welding needle, and the flat-headed welding needle 5 performs resistance welding between the current collector and the shell bottom 11. The end of the welding head 52 of the flat-headed welding needle 5 has a planar feature, which can ensure a larger resistance welding area, thereby improving the shock resistance performance, high-rate charge and discharge performance of the cylindrical battery, and avoiding the safety risks caused by high battery temperature.

[0034] 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 welding structure for a power battery, characterized in that, The device includes an insulating pad and a flat-head welding needle. The insulating pad includes an insulating body with a central through hole in the middle. Several spring pieces are evenly distributed circumferentially on the inner wall of the central through hole. The spring pieces extend downward from the inner wall of the central through hole and form a trumpet shape. The free ends of the spring pieces form a through hole. The through hole is used to insert the flat-head welding needle and abut against the rod of the flat-head welding needle so that the flat-head welding needle is set vertically.

2. The welding structure of the power battery as described in claim 1, characterized in that, The spring sheet gradually contracts in the direction away from the central through hole so that a gap is formed between two adjacent spring sheets.

3. The welding structure of the power battery as described in claim 2, characterized in that, The insulating body is also provided with a strip-shaped through groove and several seepage holes.

4. The welding structure of the power battery as described in claim 3, characterized in that, The power battery also includes a housing and bare cells disposed within the housing. The bare cells have a central hole in the middle, and the central through hole is correspondingly disposed to the central hole.

5. The welding structure of the power battery as described in claim 4, characterized in that, The power battery includes a first current collector, and the insulating pad is disposed on the first current collector, with the edge of the insulating pad being bonded to the edge of the bare cell by insulating tape.

6. The welding structure of the power battery as described in claim 5, characterized in that, The first collector plate includes a collector body and an extension handle extending outward from the collector body. The extension handle is bent towards the upper part of the collector body and passes through the strip-shaped through groove.

7. The welding structure of the power battery as described in claim 6, characterized in that, One side of the bare battery cell is welded to the first current collector, and the other side of the bare battery cell is welded to the second current collector. The flat-head welding needle includes the rod and a welding head at one end of the rod. The flat-head welding needle passes through the through hole and the central hole, and the welding head presses against the middle of the second current collector to weld the second current collector to the housing.

8. The welding structure of the power battery as described in claim 7, characterized in that, The cross-sectional dimension of the welding head is smaller than that of the rod.

9. The welding structure of the power battery as described in claim 1, characterized in that, The insulating pad is made of plastic.

10. The welding structure of the power battery as described in claim 1, characterized in that, The perforated portion is circular and the diameter of the perforated portion is a first diameter. The diameter of the shank of the flat-headed welding needle is a second diameter. The difference between the first diameter and the second diameter is greater than or equal to -0.1 mm and less than or equal to 0.1 mm.

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