Negative electrode tab and battery pack

Abstract

The utility model provides a negative pole lug and a battery pack, and relates to the technical field of batteries, the negative pole lug comprises a first section of pole lug and a second section of pole lug which are made of different materials; the first-section tab comprises a welding part and a switching part, the welding part is used for being connected with the negative plate in a welding manner, and the first-section tab is made of nickel; the second section of tab is overlapped and welded with the switching part, one end, far away from the switching part, of the second section of tab is used for being connected with the shell, and the second section of tab and the shell are made of the same material. According to the negative pole lug provided by the utility model, the first pole lug section and the second pole lug section are connected in an overlapping welding manner, so that the connection strength and stability of the first pole lug section and the second pole lug section which are made of different materials can be ensured, and the first pole lug section can ensure good conductivity and welding strength between the first pole lug section and the negative pole piece; and the second section of tab can have good metal compatibility with the shell of the battery pack, so that the welding strength of the negative tab is improved, and the liquid leakage risk of the battery pack is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a negative electrode tab and a battery pack. Background Art

[0002] With the development of medical technology, active implantable neurostimulators are increasingly used in disease detection and treatment. For active implantable neurostimulators, the batteries that power them must have high energy density, long-term safety, and stability.

[0003] The negative electrode tab is a crucial component of the battery. In related technologies, the housing of active implantable neurostimulators is typically made of materials such as titanium, while the negative electrode tab is typically made of pure nickel. The negative electrode tab and the housing are connected using a clamp-welding process. However, due to the poor compatibility of pure nickel and titanium when welding, the weld is prone to fracture, which can lead to leakage and compromise battery safety and stability. Utility Model Content

[0004] The embodiments of the present utility model provide a negative electrode tab and a battery pack, which can improve the welding strength of the negative electrode tab and reduce the risk of battery pack leakage.

[0005] In a first aspect, an embodiment of the present invention provides a negative electrode tab for connecting a housing and a negative electrode sheet in a battery pack, comprising a first tab and a second tab of different materials;

[0006] The first section of the tab includes a welding portion and a transition portion, the welding portion is used for welding and connecting with the negative electrode sheet, and the material of the first section of the tab is nickel;

[0007] The second section of the tab is overlapped and welded with the transition portion, and one end of the second section of the tab away from the transition portion is used to be connected to the shell, and the second section of the tab and the shell are made of the same material.

[0008] In some embodiments, the distance between the welding portion and the transition portion is 0-1.0 mm.

[0009] In some embodiments, the length of the transition portion along the extending direction of the first section of the tab and the second section of the tab is 2.0-3.0 mm.

[0010] In some embodiments, the first section of the tab and the second section of the tab are connected by laser spot welding, and the number of welding points is set to 4-6.

[0011] In some embodiments, the widths of the first section of the tab and the second section of the tab are 1.5-3.0 mm, and the widths of the first section of the tab and the second section of the tab are the same.

[0012] In some embodiments, the thickness of the first section of the tab and the second section of the tab is 0.05-0.1 mm.

[0013] In a second aspect, the present invention provides a battery pack comprising the negative electrode tab as described above.

[0014] In some embodiments, the battery pack further comprises a battery cell and a housing;

[0015] The battery cell is arranged in the shell, and a negative electrode sheet is arranged in the battery cell;

[0016] The housing comprises an upper cover plate and a housing;

[0017] The welding portion of the first-section electrode tab is welded to the negative electrode sheet, and one end of the second-section electrode tab away from the adapter portion is clamp-welded to the shell and the upper cover.

[0018] In some embodiments, a ratio of the length of the welding portion to the width of the negative electrode sheet is 2:3-1:1.

[0019] In some embodiments, the battery pack further includes an insulating film, wherein the insulating film covers a welding area between the welding portion and the negative electrode sheet.

[0020] Beneficial effects of the embodiments of the present utility model:

[0021] In an embodiment of the present invention, a negative electrode tab is provided, comprising a first section tab and a second section tab made of different materials, the first section tab being provided with a welding portion and a transition portion, the second section tab being overlapped and welded with the transition portion, and the welding portion being used for welding and connecting with the negative electrode sheet of the battery pack; the first section tab and the second section tab are overlapped and welded to each other, so that a stable connection between the first section tab and the second section tab of different materials can be achieved, with less deformation and higher connection strength; the material of the first section tab is nickel, and the material of the second section tab is the same as that of the shell in the battery pack, the first section tab made of nickel has good conductivity, and after the first section tab is welded to the negative electrode sheet through the welding portion, good conductivity and high connection strength can be ensured, and the second section tab made of the same material as the shell can have good metal compatibility with the shell of the battery pack, thereby improving the welding strength of the negative electrode tab and reducing the risk of leakage of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 Schematic diagram of the structure of the negative electrode tab provided by an embodiment of the present utility model;

[0024] Figure 2 yes Figure 1 Cross-sectional view at AA in the middle;

[0025] Figure 3 yes Figure 2 The enlarged structure diagram at B in the middle;

[0026] Figure 4 This is a schematic structural diagram of the negative electrode tab and the negative electrode sheet after welding provided by an embodiment of the present utility model;

[0027] Figure 5 This is an exploded structural diagram of a battery pack provided by an embodiment of the present utility model;

[0028] Figure 6 It is a cross-sectional view of a battery pack provided by an embodiment of the present utility model.

[0029] Description of reference numerals:

[0030] 1. Negative electrode tab; 11. First section of tab; 111. Welding part; 112. Adapter; 12. Second section of tab; 2. Upper cover; 3. Battery cell; 31. Negative electrode sheet; 311. Empty foil area of ​​current collector; 312. Insulating film; 4. Shell; 5. Lower cover; 6. Negative electrode post; 100. Battery pack. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In the present invention, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0032] In a first aspect, embodiments of the present invention provide a negative electrode tab 1 for connecting the housing 4 and the negative electrode sheet 31 in a battery pack 100. The tab comprises a first tab section 11 and a second tab section 12 made of different materials. The first tab section 11 comprises a welding portion 111 and a transition portion 112. The welding portion 111 is welded to the negative electrode sheet 31 and is made of nickel. The second tab section 12 is welded to the transition portion 112 in an overlapping manner. The end of the second tab section 12, distal from the transition portion 112, is connected to the housing 4. The second tab section 12 and the housing 4 are made of the same material.

[0033] like Figure 1-3 As shown, the negative electrode tab 1 provided by the present invention includes a first section tab 11 and a second section tab 12 , wherein the first section tab 11 is used to connect to the negative electrode sheet 31 in the battery pack 100 , and the second section tab 12 is used to connect to the shell 4 in the battery pack 100 .

[0034] For example, the shell 4 may be made of titanium or titanium alloy, and the grade may be TA1, TA2 or TC4, etc.; the second section of the tab 12 may also be made of TA1, TA2 or TC4, etc.

[0035] For active implantable neurostimulators, the battery pack 100 housing 4 is typically made of titanium. To effectively connect the negative tab 1 to the negative electrode sheet 31, a highly conductive material, such as nickel, must be used for welding. However, pure nickel and titanium have poor compatibility. If a pure nickel negative tab 1 is used, the weld seam is susceptible to fracture during clamp welding between the negative tab 1 and the titanium housing, potentially leading to leakage. Leakage within the patient's body can be particularly serious for active implantable neurostimulators.

[0036] In response to the above technical issues, such as Figure 1-4 As shown, the present invention forms a negative electrode tab 1 by overlapping and connecting a first tab 11 made of nickel and a second tab 12 made of the same material as the shell 4. The first tab 11 is connected to the negative electrode sheet 31 via a welding portion 111, ensuring good conductivity. The end of the second tab 12 away from the adapter 112 is connected to the shell 4 of the battery pack 100. Due to the good metal compatibility, the connection strength of the negative electrode tab 1 can be improved, the risk of leakage can be reduced, and the safety and stability of the battery pack 100 can be improved. In addition, the second tab 12 is overlapped and welded with the adapter 112, that is, the first tab 11 and the second tab 12 are connected by lap welding, which can achieve a stable connection between the first tab 11 and the second tab 12 of different materials, with less deformation and higher connection strength.

[0037] In some embodiments, a distance D between the welding portion 111 and the transition portion 112 is 0-1.0 mm.

[0038] like Figure 4 As shown, since the first section of the tab 11 and the second section of the tab 12 overlap and connect in the area of ​​the transition portion 112 and have a large thickness, they will interfere with the welding between the first section of the tab 11 and the negative electrode sheet 31. Therefore, the welding portion 111 avoids the area where the transition portion 112 is located, and the welding portion 111 and the transition portion 112 in the first section of the tab 11 do not overlap with each other. In addition, the space inside the battery pack 100 is relatively compact. If the spacing between the welding portion 111 and the transition portion 112 in the first section of the tab 11 is too large, it will affect the space utilization rate in the battery pack 100, resulting in an abnormal increase in the size of the battery pack 100. Moreover, the large spacing can easily lead to a close distance between the transition portion 112 and the shell 4, resulting in the risk of the first section of the tab 11 and the second section of the tab 12 made of different materials fusing together when welding the negative tab 1 to the shell 4, resulting in a reduction in the welding strength between the negative tab 1 and the shell 4. Especially when the battery pack 100 is applied to an active implantable neurostimulator, it is necessary to consider reducing the size of the battery pack 100 as much as possible. Taking all factors into consideration, the spacing D between the welding portion 111 and the adapter portion 112 is set to 0-1.0 mm to improve space utilization.

[0039] Furthermore, the distance D between the welding portion 111 and the transition portion 112 can be further optimized to 0-0.5 mm.

[0040] In some embodiments, the length of the transition portion 112 along the extending direction of the first section of the electrode tab 11 and the second section of the electrode tab 12 is 2.0-3.0 mm.

[0041] For example, the length of the transition portion 112 along the extending direction of the first section of the tab 11 and the second section of the tab 12 may be 2.0 mm, 2.3 mm, 2.5 mm, 2.8 mm or 3.0 mm.

[0042] That is, the length of the overlapping connection area between the first and second tabs 11, 12 is 2.0-3.0 mm. If the transition portion 112 is too short, the connection between the first and second tabs 11, 12 is less stable, which can easily lead to short circuits. If the transition portion 112 is too long, the transition portion 112 needs to be accommodated within the battery pack 100, which will result in a larger space occupation, thus affecting the overall size of the battery pack 100. By setting the transition portion 112 length to 2.0-3.0 mm, a high connection strength between the first and second tabs 11, 12 is ensured, while also avoiding the problem of an excessively long transition portion causing an increase in the size of the battery pack 100.

[0043] In some embodiments, as Figure 1As shown, the first section of the tab 11 and the second section of the tab 12 are connected by laser spot welding, and the number of welding points is set to 4-6.

[0044] Since the materials of the first section of the pole tab 11 and the second section of the pole tab 12 are different, laser spot welding is used to connect them, which can achieve welding of dissimilar materials between the first section of the pole tab 11 and the second section of the pole tab 12. In addition, laser spot welding has small residual stress and welding deformation, and can achieve high-precision welding.

[0045] When laser spot welding the first and second tabs 11 and 12, the number of welding points can be set to 4-6. The length of the transition portion 112 is 2.0-3.0 mm. Depending on the laser spot welding conditions and the length of the area, setting 4-6 welding points can ensure connection stability and reduce welding difficulty.

[0046] For example, Figure 1 As shown, the number of welding points can be set to 4.

[0047] In some embodiments, the width of the first section of the tab 11 and the second section of the tab 12 is 1.5-3.0 mm, and the width of the first section of the tab 11 and the width of the second section of the tab 12 are the same.

[0048] Illustratively, the width of the first section of the tab 11 and the second section of the tab 12 may be 1.5 mm, 1.8 mm, 2.0 mm, 2.5 mm, or 3.0 mm.

[0049] The first section of the tab 11 and the second section of the tab 12 are connected to the negative electrode sheet 31 and the shell respectively, and the first section of the tab 11 and the second section of the tab 12 are also overlapped and connected to each other. In order to ensure that the negative electrode tab 1 has good conductivity and can be stably connected to the negative electrode sheet 31 and the shell, the width of the first section of the tab 11 and the second section of the tab 12 can be set to 1.5-3.0.0mm, and the width of the first section of the tab 11 and the second section of the tab 12 is the same.

[0050] In some embodiments, the thickness of the first section of the tab 11 and the second section of the tab 12 is 0.05-0.1 mm.

[0051] For example, the thickness of the first section of the tab 11 and the second section of the tab 12 may be 0.05 mm, 0.07 mm, 0.09 mm or 0.1 mm.

[0052] If the thickness of the first and second tabs 11, 12 is too large, when the second tab 12 is clamped and welded to the shell, the weld gap at the clamping position is likely to be too large, which can easily cause problems such as poor welding. If the thickness of the first and second tabs 11, 12 is too small, the welding strength at the transition portion 112 is likely to be low, and the weld structure strength at the clamping weld between the second tab 12 and the shell will also be low. Therefore, the thickness range of the first and second tabs 11, 12 is set to 0.05-0.1mm.

[0053] It should be noted that the thicknesses of the first section of the electrode tab 11 and the second section of the electrode tab 12 may be the same or different.

[0054] Second, as Figure 4-6 As shown, the present invention provides a battery pack 100 including the negative electrode tab 1 as described above.

[0055] The beneficial effects of the battery pack 100 provided by the present invention relative to the prior art are basically the same as those of the negative electrode tab 1 and will not be described in detail here.

[0056] In some embodiments, as Figure 4-6 As shown, the battery pack 100 further includes a battery cell 3 and a shell;

[0057] The battery cell 3 is disposed in the housing, and a negative electrode sheet 31 is disposed in the battery cell 3;

[0058] The housing includes an upper cover plate 2 and a housing 4;

[0059] The welding portion 111 of the first-section electrode tab 11 is welded to the negative electrode sheet 31 , and one end of the second-section electrode tab 12 away from the transition portion 112 is clamp-welded to the housing 4 and the upper cover plate 2 .

[0060] The shell 4 is usually made of titanium, and the upper cover 2 is made of titanium or titanium alloy.

[0061] The second section of the tab 12 is clamped and welded to the shell 4 and the upper cover 2. That is, when the shell of the battery pack 100 is assembled, the upper cover 2 is pressed into the shell 4, and a clearance fit or interference fit is formed between the upper cover 2 and the shell 4. The second section of the tab 12 is clamped between the upper cover 2 and the shell 4 during the assembly process, and then the upper cover 2, the shell 4 and the second section of the tab 12 are welded.

[0062] like Figure 4-6As shown, one end of the first tab 11 of the negative electrode tab 1 is welded to the negative electrode sheet 31, and one end of the second tab 12 is clamp-welded to the housing 4 and the upper cover 2, thereby forming the negative electrode of the battery pack 100. Because the negative electrode tab 1 provided in this embodiment of the utility model adopts a nickel-to-titanium structure (the first tab 11 is made of nickel, the second tab 12 is made of titanium, and the first and second tabs 11 and 12 are overlapped and connected), the welded portion of the first tab 11 is welded to the negative electrode sheet 31 to ensure conductivity, and the second tab 12 is clamp-welded to the housing 4 and the upper cover 2 to improve welding strength.

[0063] Specifically, if Figure 4 As shown, the welding portion 111 of the first section of the pole tab 11 is welded to the empty foil area 311 of the current collecting network in the negative electrode sheet 31. The material of the empty foil area 311 of the current collecting network is generally copper, nickel, aluminum, stainless steel, etc. The first section of the pole tab 11 made of nickel can form a stable connection with the empty foil area 311 of the current collecting network and can ensure the conductive performance; the welding portion 111 of the first section of the pole tab 11 can be welded to the empty foil area 311 of the current collecting network by ultrasonic welding.

[0064] The second section of the tab 12 is connected to the housing 4 and the upper cover 2 by clamp welding. During welding, the penetration depth is set to be greater than or equal to 0.2 mm to improve the welding strength.

[0065] Furthermore, if Figure 5-6 As shown, the battery pack 100 also includes a lower cover plate 5 and a negative electrode post 6. The shell 4 is a structure with upper and lower openings. The upper cover plate 2 and the lower cover plate 5 are respectively used to be assembled to the openings at the upper and lower ends of the shell 4; after the second section of the tab 12 is clamped and welded to the shell 4 and the upper cover plate 2, the shell of the battery pack 100 forms the negative electrode of the battery pack 100, and the negative electrode post 6 is arranged on the upper cover plate 2, which can facilitate the power supply of the battery pack 100.

[0066] In some embodiments, as Figure 4 As shown, the ratio of the length of the welding portion 111 to the width of the negative electrode sheet 31 is 2:3-1:1.

[0067] That is, the first section of the tab 11 is welded to at least 2 / 3 of the width of the negative electrode sheet 31. If the length of the welding portion 111 is too short, the welding tension between the first section of the tab 11 and the negative electrode sheet 31 is likely to be too low, which may cause the negative electrode tab 1 to fall off and cause a short circuit.

[0068] In addition, the length of the second section of the tab 12 can be set to 8.0-12.0 mm, and the specific length can be adjusted according to actual needs. Since the second section of the tab 12 is clamp-welded to the shell 4 and the upper cover 2, the part outside the battery pack 100 shell can be trimmed and removed after the clamp-welding connection is completed.

[0069] In some embodiments, as Figure 4 As shown, the battery pack 100 further includes an insulating film 312 , and the insulating film 312 covers the welding area between the welding portion 111 and the negative electrode sheet 31 .

[0070] The insulating film 312 covering the welding area between the welding portion 111 and the negative electrode sheet 31 can reduce or avoid short circuit problems and provide insulation protection for the negative electrode tab 1 located in the battery cell 3. Furthermore, the area of ​​the insulating film 312 is larger than the area of ​​the welding portion 111. The insulating film 312 can cover the welding portion 111 as well as the surrounding area of ​​the welding portion 111, thereby improving the insulation protection capability.

[0071] The above is a detailed introduction to the embodiments of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, based on the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A negative electrode tab, used to connect the shell and the negative electrode sheet in a battery pack, characterized in that: It includes a first section of pole lug and a second section of pole lug made of different materials; The first section of the pole tab includes a welding portion and a transition portion, the welding portion is used for welding and connecting with the negative electrode sheet, and the material of the first section of the pole tab is nickel; The second-section pole ear is overlapped and welded with the transition portion, an end of the second-section pole ear away from the transition portion is used to be connected to the shell, and the second-section pole ear and the shell are made of the same material.

2. The negative electrode tab according to claim 1, characterized in that: The distance between the welding portion and the transition portion is 0-1.0 mm.

3. The negative electrode tab according to claim 1, characterized in that: The length of the transition portion along the extending direction of the first section of the pole lug and the second section of the pole lug is 2.0-3.0 mm.

4. The negative electrode tab according to claim 3, characterized in that: The first section of the pole tab and the second section of the pole tab are connected by laser spot welding, and the number of welding points is set to 4-6.

5. The negative electrode tab according to claim 1, characterized in that: The widths of the first section of the pole lug and the second section of the pole lug are 1.5-3.0 mm, and the widths of the first section of the pole lug and the second section of the pole lug are the same.

6. The negative electrode tab according to claim 5, characterized in that: The thickness of the first section of the electrode tab and the second section of the electrode tab is 0.05-0.1 mm.

7. A battery pack, characterized in that: Comprising the negative electrode tab as described in any one of claims 1 to 6.

8. The battery pack according to claim 7, characterized in that: The battery pack also includes a battery cell and a shell; The battery cell is arranged in the shell, and a negative electrode sheet is arranged in the battery cell; The housing comprises an upper cover plate and a housing; The welding portion of the first-section pole tab is welded to the negative electrode sheet, and one end of the second-section pole tab away from the adapter portion is clamp-welded to the shell and the upper cover plate.

9. The battery pack according to claim 8, characterized in that: The ratio of the length of the welding portion to the width of the negative electrode sheet is 2:3-1:

1.

10. The battery pack according to claim 9, characterized in that: The battery pack further includes an insulating film, and the insulating film covers a welding area between the welding portion and the negative electrode sheet.

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