Conductive tab, welding product, and welding method

Abstract

To reduce an invalid split flow in resistance welding.SOLUTION: A conductive tab 10 is resistance-welded to an electrode 91. The conductive tab 10 includes a first conductive sheet 20 having a first part (specific part 22BA) which is resistance-welded to the electrode 91, and a second conductive sheet having a second part (specific part 42BA) which is resistance-welded to the electrode 91 together with the first part. An end R1 of the first conductive sheet 20 and an end L1 of the second conductive sheet 40 overlap each other through an insulation layer 30, and the first conductive sheet 20 and the second conductive sheet 40 include notches 22C an 42C forming a slit H between the first part and the second part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a conductive tab, a welding product, and a welding method. [Background technology]

[0002] When a conductive tab is resistance-welded to a welding target such as a battery, a portion of the welding current may become an ineffective shunt current (current that does not contribute to resistance welding) that flows within the conductive tab instead of flowing to the welding target material. To reduce this ineffective shunt current, Patent Document 1 discloses a technique for providing a slit between two portions that are respectively in contact with a pair of electrodes through which the welding current flows. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-226699 Summary of the Invention [Problem to be solved by the invention]

[0004] Even if a slit is provided as in Patent Document 1, an ineffective shunt flow may occur that bypasses the slit, and the ineffective shunt flow may not be reduced sufficiently.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to effectively reduce ineffective shunt current during resistance welding. [Means for solving the problem]

[0006] In order to solve the above problem, the conductive tab of the present invention is a conductive tab that is resistance-welded to a welding object, and comprises a first conductive sheet having a first portion that is resistance-welded to the welding object, and a second conductive sheet having a second portion that is resistance-welded to the welding object together with the first portion, wherein a portion of the first conductive sheet and a portion of the second conductive sheet overlap with each other via an insulating layer, and at least one of the first conductive sheet and the second conductive sheet has a notch that forms a slit between the first portion and the second portion by overlapping the portion of the first conductive sheet with the portion of the second conductive sheet.

[0007] As an example, the insulating layer covers the first conductive sheet from the second conductive sheet side in a shape that protrudes from the portion of the first conductive sheet.

[0008] As an example, the insulating layer covers the second conductive sheet from the first conductive sheet side in a shape that protrudes from the portion of the second conductive sheet.

[0009] As an example, the conductive tab further includes an insulating material that sandwiches the first conductive sheet and the second conductive sheet, which sandwich the insulating layer, from above and below when the thickness direction of the first conductive sheet and the second conductive sheet is the vertical direction.

[0010] As an example, the conductive tab has a dish-shaped protrusion protruding toward the welding object, the protrusion having a cylindrical portion and a bottom extending inward from the cylindrical portion and including the first portion and the second portion, and the slit is formed in a shape that is contained within the bottom and does not reach the cylindrical portion.

[0011] A welded product according to the present invention includes the conductive tab described above and a battery having, as the welding target, an electrode to which the conductive tab is resistance-welded.

[0012] As an example, the welding product further includes a cylindrical sealing member interposed between the electrode and the conductive tab and surrounding the slit in a plan view.

[0013] The welding method of the present invention is a welding method for resistance welding the conductive tab to the welding object, in which one of a pair of welding electrodes is placed against the first portion and the other is placed against the second portion to perform resistance welding. [Effects of the Invention]

[0014] According to the present invention, ineffective shunt current during resistance welding is effectively reduced. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a plan view of a conductive tab according to an embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the conductive tab of FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 4 is a partial cross-sectional view showing the state in which the conductive tab is resistance-welded to the electrode. [Figure 5] FIG. 5 is a partial end view showing a cross section of the battery pack according to the embodiment of the present invention when cut along a plane extending in the up-down and left-right directions. [Figure 6] FIG. 6 is a perspective view of an insulating layer and a second conductive sheet of a conductive tab according to a modified example. [Figure 7] FIG. 7 is an exploded perspective view of a conductive tab according to a modified example. [Figure 8] 8 is an end view showing a cross section of the conductive tab of FIG. 7 cut along a plane passing through the dashed line B of FIG. 7 and parallel to the up-down direction. [Figure 9] 9 is an end view showing a cross section of the conductive tab of FIG. 7 cut along a plane passing through the dashed dotted line C of FIG. 7 and parallel to the up-down direction. [Figure 10] FIG. 10 is an enlarged plan view of a convex portion of a conductive tab according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each element shown in the drawings (especially the dimensions such as the thickness of each element) is drawn in an exaggerated and schematic manner. The directions of up, down, left, right, front, and back in the drawings are for convenience only and may not coincide with the actual top-to-bottom directions, horizontal directions, etc. A view of the drawings from above is called a plan view.

[0017] The conductive tab 10 according to this embodiment shown in FIGS. 1 to 3 is configured to weld electrodes 91 (positive electrodes in this case) of multiple batteries 90 by resistance welding to these electrodes 91. The conductive tab 10 includes a first conductive sheet 20, an insulating layer 30, and a second conductive sheet 40. The first conductive sheet 20 and the second conductive sheet 40 are made of a metal such as copper or a copper alloy. The first conductive sheet 20 and the second conductive sheet 40 may include a plated layer of tin or the like. The insulating layer 30 is made of any insulating material such as synthetic resin. Examples of this insulating material include heat-resistant polyimide.

[0018] The first conductive sheet 20 includes a flat plate portion 21 and two arch-shaped protrusions 22, each having a central angle greater than 180 degrees in plan view, protruding downward from the flat plate portion 21 toward the electrode 91. The two protrusions 22 are identical in shape and are arranged on the right side of the first conductive sheet 20 with a gap in the front-to-rear direction. In plan view, the side that forms the chord of the arch of the protrusion 22 forms the right side of the first conductive sheet 20. The protrusions 22 are formed in a shape obtained by bending a flat plate. The protrusions 22 are arc-shaped in plan view and include an inclined portion 22A that extends downward from the flat plate portion 21 so as to gradually approach the electrode 91 from the outer periphery toward the inner periphery, and a flat bottom 22B that extends from the lower end of the inclined portion 22A toward the inner periphery. The bottom 22B has a notch 22C that opens to the right side of the first conductive sheet 20 and extends in the front-to-rear direction. The flat plate portion 21 of the first conductive sheet 20 has a terminal 21A that is electrically connected to the outside in order to supply current from the battery 90 to the outside. The shape and position of the terminal 21A are arbitrary.

[0019] The insulating layer 30 covers a portion of the first conductive sheet 20 from above (the side facing the second conductive sheet 40). The insulating layer 30 includes a flat portion 31 and two protruding portions 32 that respectively cover the flat portion 21 and the two protruding portions 22 of the first conductive sheet 20. The flat portion 31 covers the entire flat portion 21 from above, except for the terminals 21A of the flat portion 21. The two protruding portions 32 are formed to have the same shape as each other. The protruding portion 32 includes an inclined portion 32A that covers the inclined portion 22A of the first conductive sheet 20, and a bottom 32B that covers the bottom 22B. The inclined portion 32A has the same shape as the inclined portion 22A. In other words, the inclined portion 32A is arc-shaped in a plan view and extends downward from the flat portion 31 so as to gradually approach the electrode 91 from the outer periphery toward the inner periphery. The bottom 32B is formed in a flat plate shape that extends from the lower end of the inclined portion 32A toward the inner periphery. Bottom 32B is formed with notch 32C that overlaps notch 22C and has a shape similar to notch 22C, and notch 32D that is formed by further cutting bottom 32B from notch 32C. Notch 32D exposes specific portion 22BA of bottom 22B of first conductive sheet 20 upward. Specific portion 22BA is a portion that is resistance-welded to electrode 91.

[0020] The second conductive sheet 40 has a shape that is approximately bilaterally symmetrical to the first conductive sheet 20 in a plan view. The second conductive sheet 40 includes a flat plate portion 41 and two protruding portions 42 that are arch-shaped in a plan view and protrude downward from the flat plate portion 41. The two protruding portions 42 are formed to have the same shape and are arranged on the left side of the second conductive sheet 40 with a gap in the front-to-rear direction. In a plan view, the side that forms the chord of the arch of the protruding portion 42 forms the left side of the second conductive sheet 40. The protruding portion 42 is formed in a shape obtained by bending a flat plate. The protruding portion 42 has an arc shape in a plan view and includes an inclined portion 42A that extends downward from the flat plate portion 41 so as to gradually approach the electrode 91 from the outer periphery toward the inner periphery, and a flat bottom 42B that extends from the lower end of the inclined portion 42A toward the inner periphery. The bottom 42B has a notch 22C extending in the front-rear direction that opens to the left side of the second conductive sheet 40. The flat plate portion 41 of the second conductive sheet 40 has a terminal 41A that is electrically connected to the outside in order to supply current from the battery 90 to the outside. The shape and position of the terminal 41A are arbitrary.

[0021] The left end L1 (part marked by the dashed-dotted line in FIG. 2) of the second conductive sheet 40 overlaps and is fixed to the right end R1 (part marked by the dashed-dotted line in FIG. 2) of the first conductive sheet 20 via the right end R2 (part marked by the dashed-dotted line in FIG. 2) of the insulating layer 30. Each of the ends R1, R2, and L1 is made up of multiple parts separated by notches 22C, 32C, and 42C, respectively. The end R2 and end L1, which cover the end R1, have cross-sectional shapes that abut each other without leaving any gaps.

[0022] The overlapping of the ends R1, R2, and L1 forms the conductive tab 10 with a flat plate portion 11 and two circular, dish-shaped protrusions 12 protruding downward (toward the electrode 91) from the flat plate portion 11 in a plan view. The flat plate portion 11 is composed of flat plate portions 21, 31, and 41. The two protrusions 12 are formed to have the same shape. The protrusions 12 are composed of protrusions 22, 32, and 42. The protrusions 12 have a side surface shape of a truncated cone that gradually approaches the electrode 91 from the outer periphery to the inner periphery. The protrusions 12 include a cylindrical portion 12A extending from the flat plate portion 11 toward the electrode 91 and a bottom 12B extending inward from the cylindrical portion 12A. The cylindrical portion 12A is composed of inclined portions 22A, 32A, and 42A, and the bottom 12B is composed of bottoms 22B, 32B, and 42B. The bottom 12B has a slit H that is long in the front-rear direction formed by the cutouts 22D, 32D, and 42D. The slit H is contained within the bottom 12B and does not reach the cylindrical portion 12A.

[0023] The conductive tab 10 is formed, for example, by the following method. First, a combination of the first conductive sheet 20 and the insulating layer 30 is formed by insert molding or the like. The combination of the first conductive sheet 20 and the insulating layer 30 may be formed by forming the insulating layer 30 as an insulating sheet and then fixing the insulating layer 30 to the first conductive sheet 20 by using double-sided tape or an adhesive, or by thermocompression bonding. The second conductive sheet 40 is then fixed to the combination formed by these methods by using double-sided tape or an adhesive, or by thermocompression bonding, etc. This completes the conductive tab 10. As another example, after forming a flat combination of the first conductive sheet 20, the insulating layer 30, and the second conductive sheet 40, the protrusions 12 may be formed by embossing, pressing, or the like.

[0024] The protrusions 12 of the conductive tab 10 are resistance-welded to electrodes 91 of the battery 90. Here, one electrode 91 is resistance-welded for each protrusion 12. As shown in FIG. 4 , a pair of welding electrodes E1 and E2 for resistance welding are applied from the same direction, i.e., from above, to the specific portion 22BA of the first conductive sheet 20 and the specific portion 42BA of the bottom 42B of the protrusion 42 of the second conductive sheet 40, which are separated from each other by the slit H located between them. The specific portion 42BA is set at a position symmetrical to the left and right of the slit H of the specific portion 22BA (the area surrounded by the dashed line in FIG. 1 ). Thereafter, the pair of electrodes E1 and E2 are energized while pressing the specific portion 22BA and the specific portion 42BA, i.e., the conductive tab 10, against the electrode 91 of the battery 90. As a result, for example, welding current I from electrode E1 flows to electrode E2 via specific portion 22BA of first conductive sheet 20, electrode 91 of battery 90, and specific portion 42BA of second conductive sheet 40 in this order, and specific portion 22BA and specific portion 42BA of conductive tab 10 are simultaneously resistance-welded to electrode 91 of battery 90. If conductive tab 10 is made of copper or the like, conductive tab 10 is diffusion-bonded to electrode 91 by resistance welding.

[0025] During resistance welding, a cylindrical seal member 70 that surrounds the slit H in a plan view may be interposed between the conductive tab 10 and the battery 90. The seal member 70 is made of an elastic rubber material, synthetic resin, or the like. When the pair of electrodes E1 and E2 press the conductive tab 10 against the electrode 91 of the battery 90, the seal member 70 elastically deforms and adheres closely to the conductive tab 10 (particularly the bottom 12B of the protrusion 12) and the electrode 91. This seal member 70 prevents liquids, such as water, that have entered the battery 90 through the slit H from flowing around the battery 90. This effect is particularly effective in a battery pack 100, for example, as shown in FIG. 5, that includes a battery 90, a conductive tab 10 welded to the battery 90, a housing 110 that houses them, and a seal member 120 that seals between the housing 110 and the conductive tab 10. The seal member 70 prevents liquid from entering between the battery 90 and the housing 110 and prevents corrosion and other problems that may occur as a result.

[0026] As described above, the end portion R1 of the first conductive sheet 20 and the end portion L1 of the second conductive sheet 40 overlap with the insulating layer 30 interposed therebetween, thereby insulating the first conductive sheet 20 and the second conductive sheet 40 from each other. Furthermore, the first conductive sheet 20 and the second conductive sheet 40 form slits H by the notches 22C and 42C, respectively. During resistance welding, the pair of electrodes E1 and E2 are placed against the specific portion 22BA and the specific portion 42BA of the conductive tab 10, respectively, across the slit H. This configuration suppresses the generation of ineffective shunt current (i.e., current that does not contribute to resistance welding) during resistance welding. This current flows from the electrode E1 to the specific portion 22BA of the first conductive sheet 20 and then directly to the specific portion 22BA of the second conductive sheet without passing through the electrode 91. In particular, in this embodiment, the insulating layer 30 suppresses the generation of ineffective shunt current that bypasses the slit H. In this manner, this embodiment effectively suppresses ineffective shunt current.

[0027] Furthermore, in this embodiment, the insulating layer 30 covers the first conductive sheet 20 from the second conductive sheet 40 side, except for the specific portion 22BA and the terminal 21A, thereby covering the first conductive sheet 20 in a shape that protrudes from the end R1 of the first conductive sheet 20. If the insulating layer 30 had the same shape as the end R1 in a plan view, the creepage distance of the insulating layer 30 between the first conductive sheet 20 and the second conductive sheet 40 would be shortened by the thickness (vertical length) of the insulating layer 30, and ineffective shunt current due to creepage discharge may occur during resistance welding. By covering the first conductive sheet 20 in a shape that protrudes from the end R1 of the first conductive sheet 20, the creepage distance of the insulating layer 30 can be made longer than if the insulating layer 30 had the same shape as the end R1 in a plan view, and ineffective shunt current is more effectively suppressed.

[0028] From the same viewpoint as above, it is preferable that the insulating layer 30 protrudes beyond the end portion L1 of the second conductive sheet 40 and covers the second conductive sheet 40 from the first conductive sheet 20 side. This also increases the creepage distance of the insulating layer 30 compared to when the insulating layer 30 has the same shape as the end portion L1 in a plan view, and more effectively suppresses reactive shunt current. In such a case, as shown in FIG. 6 , the insulating layer 30 may be formed in a shape that covers the portion of the second conductive sheet 40 other than the specific portion 42BA and the terminal 41A from the first conductive sheet 20 side, i.e., from below. The insulating layer 30 in FIG. 6 includes a protrusion 39 that constitutes the protrusion 12. The bottom of the protrusion 39 is formed with a through-hole 30Z that constitutes the slit H and exposes the specific portion 22BA of the first conductive sheet 20 and the specific portion 42BA of the second conductive sheet 40.

[0029] As in the above embodiment, the slit H is positioned within the bottom 12B and does not reach the cylindrical portion 12A (see, for example, Figure 1), so that the edge of the slit H can be pressed against the electrode 91 along the entire circumference, thereby reducing the amount of liquid that seeps into between the electrode 91 and the conductive tab 10 through the slit H.

[0030] Furthermore, the sealing member 70 prevents liquid that has entered the battery 90 side through the slit H from flowing around the battery 90.

[0031] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments. For example, the present invention includes various modifications to the above embodiments that are understandable to those skilled in the art within the scope of the technical concept of the present invention. Examples of modifications are given below, but each modification may be combined.

[0032] (1) As shown in Figures 7 to 9, the conductive tab 210 of the modified example includes a first conductive sheet 20 and a second conductive sheet 40 similar to those of the first embodiment, as well as an insulating layer 230 having a function similar to that of the insulating layer 30, and an insulating material 250 including a first insulating sheet 251 and a second insulating sheet 252.

[0033] The insulating layer 230 is formed only in three regions where the first conductive sheet 20 and the second conductive sheet 40 overlap (the three regions that form the ends R1 and L1), and is made up of three portions 231 to 233 that are arranged in these three regions. The insulating layer 230 has bent portions T1 to T2 that are formed by parts of the portions 231 to 233. The bent portions T1 to T2 are bent to match the shapes of the protrusions 22 and 42 so as to form the protrusion 12 together with the protrusion 22 of the first conductive sheet 20 and the protrusion 42 of the second conductive sheet 40.

[0034] Insulating material 250 is formed in a shape that sandwiches unit A, which is a combination of first conductive sheet 20, second conductive sheet 40, and insulating layer 230, from above and below (in the thickness direction). Insulating material 250 includes first insulating sheet 251 that covers unit A from above, and second insulating sheet 252 that covers unit A from below. First insulating sheet 251 and second insulating sheet 252 cover the entirety of unit A, avoiding slit H, specific portion 22BA and terminal 21A of first conductive sheet 20, and specific portion 42BA and terminal 41A of second conductive sheet 40.

[0035] The first insulating sheet 251 and the second insulating sheet 252 are formed in a shape that protrudes from the unit A toward the outer periphery, and cover the outer surfaces of the first insulating sheet 251 and the second insulating sheet 252. Furthermore, the first insulating sheet 251 and the second insulating sheet 252 are in close contact with the unit A, and also cover the side surfaces of the insulating layer 230.

[0036] The first insulating sheet 251 and the second insulating sheet 252 respectively include protrusions 251A and 252A that sandwich and cover the protrusion 12 from above and below. The bottoms of the protrusions 251A and 252A are provided with through-holes 251H and 252H that expose the slit H and the specific portion 22BA and the specific portion 42BA upward or downward, respectively.

[0037] The first insulating sheet 251 and the second insulating sheet 252 are made of various insulating materials such as polyimide. The insulating material 250 may be formed by thermocompression bonding the flat first insulating sheet 251 and the flat second insulating sheet 252 to the unit A. The insulating material 250 may be formed by insert molding, in which the unit A is inserted into a mold. In such a case, the first insulating sheet 251 and the second insulating sheet 252 are integrally molded. The insulating material 250 may be formed integrally with the insulating layer 30. For example, the insulating material 250 may be formed integrally with the insulating layer 30 by insert molding, in which the first conductive sheet 20 and the second conductive sheet 40 are inserted into a mold with a gap therebetween in the thickness direction.

[0038] In this embodiment, the first conductive sheet 20 and the second conductive sheet 40 are covered with the insulating material 250 as much as possible, so that creeping discharge, tracking, migration, and the like are effectively suppressed.

[0039] The insulating material 250 may be configured to fill part or all of the slits H so as to cover the side surfaces of the first conductive sheet 20 and the second conductive sheet 40 that form the inner walls of the slits H. The insulating material 250 (first insulating sheet 251 and second insulating sheet 252) may have a plurality of through holes that individually expose the slits H, the specific portions 22BA, and the specific portions 42BA. The structure of the insulating material 250 may be adopted for the insulating layer 30.

[0040] The insulating material 250 (first insulating sheet 251 and second insulating sheet 252) may sandwich the plurality of units A from above and below, and connect the plurality of units A in a state in which they are insulated from one another.

[0041] The insulating material 250 may be omitted, and only the insulating layer 230 may be provided in the portion where the first conductive sheet 20 and the second conductive sheet 40 overlap (the ends R1 and L1).

[0042] (2) A first insulating material may be provided to sandwich first conductive sheet 20 from above and below, avoiding terminals 21A and specific portion 22BA, and a second insulating material may be provided to sandwich second conductive sheet 40 from above and below, avoiding terminals 41A and specific portion 42BA. In this case, the overlapping portion of the first insulating material and the second insulating material forms an insulating layer between first conductive sheet 20 and second conductive sheet 40.

[0043] (3) The cutouts that form the slits H may be provided in only one of the first conductive sheet 20 and the second conductive sheet 40. For example, as shown in FIG. 10, cutout 42 may be formed only on the second conductive sheet 40 side, thereby forming slits H. In the example of FIG. 10, similar to the example of FIG. 1 etc., insulating layer 30 also covers the portions of first conductive sheet 20 that do not overlap with second conductive sheet 40. However, similar to the example of modification (1), insulating layer 30 may be formed only on the portions where first conductive sheet 20 and second conductive sheet 40 overlap. In this case, insulating material 250 may be formed.

[0044] (4) The shape of each of the above elements can be changed as appropriate. For example, the protrusion 12 may be rectangular rather than circular. Therefore, the tubular portion 12A may be cylindrical or rectangular. Furthermore, the conductive tab 10 may be flat and not have the protrusion 12.

[0045] (5) In the above embodiment, the first conductive sheet 20 and the second conductive sheet 40 are provided separately and insulated from each other without contacting each other, but the terminal 21A of the first conductive sheet 20 and the terminal 41A of the second conductive sheet 40 may be electrically connected by welding or the like. The first conductive sheet 20 and the second conductive sheet 40 may be formed by deforming a single conductive sheet in which the terminal 21A and the terminal 41A are connected.

[0046] (6) The conductive tab 10 may be welded to a component or product other than the battery 90 . [Explanation of symbols]

[0047] 10...conductive tab, 11...flat portion, 12...protruding portion, 12A...cylindrical portion, 12B...bottom, 20...first conductive sheet, 21...flat portion, 21A...terminal, 22...protruding portion, 22A...inclined portion, 22B...bottom, 22BA...specific portion, 30...insulating layer, 30Z...through hole, 31...flat portion, 32...protruding portion, 32A...inclined portion, 32B...bottom, 39...protruding portion, 40...second conductive sheet, 41...flat portion, 41A...terminal, 42...protruding portion, 42A...inclined portion, 42B...bottom, 42BA...specific portion, 70...shield a welding member, 90...battery, 91...electrode, 100...battery pack, 110...casing, 120...sealing member, 210...conductive tab, 230...insulating layer, 231-233...portions, T1-T2...bent portions, insulating material...250, 251...first insulating sheet, 251A...convex portion, 251H...through hole, 252...second insulating sheet, 252A...convex portion, 252H...through hole, A...unit, E1...electrode, E2...electrode, H...slit, I...welding current, L1...end, R1...end, R2...end.

Claims

1. A conductive tab that is resistance welded to a welding object, a first conductive sheet having a first portion to be resistance-welded to the welding object; a second conductive sheet having a second portion to be resistance-welded together with the first portion to the welding object, a portion of the first conductive sheet and a portion of the second conductive sheet overlap with each other via an insulating layer; At least one of the first conductive sheet and the second conductive sheet has a notch that forms a slit between the first portion and the second portion by overlapping the portion of the first conductive sheet and the portion of the second conductive sheet. A conductive tab comprising:

2. the insulating layer covers the first conductive sheet from the second conductive sheet side in a shape that protrudes from the portion of the first conductive sheet; The conductive tab of claim 1 .

3. the insulating layer covers the second conductive sheet from the first conductive sheet side in a shape that protrudes from the portion of the second conductive sheet; The conductive tab of claim 2 .

4. When the thickness direction of the first conductive sheet and the second conductive sheet is defined as the up-down direction, the insulating material sandwiches the first conductive sheet and the second conductive sheet with the insulating layer sandwiched therebetween from above and below. The conductive tab of claim 1 .

5. the conductive tab has a dish-shaped protrusion that protrudes toward the welding object, the protrusion includes a cylindrical portion and a bottom extending in an inner circumferential direction from the cylindrical portion and including the first portion and the second portion, The slit is formed in a shape that fits within the bottom and does not reach the cylindrical portion. The conductive tab of claim 1 .

6. The conductive tab according to any one of claims 1 to 5; a battery having an electrode to which the conductive tab is resistance-welded as the welding target; Welding products comprising:

7. The ink jet head further includes a cylindrical sealing member interposed between the electrode and the conductive tab and surrounding the slit in a plan view.

7. The welded product of claim 6.

8. A welding method for resistance welding the conductive tab according to any one of claims 1 to 5 to the welding object, comprising: Resistance welding is performed by applying one of a pair of welding electrodes to the first portion and the other to the second portion. Welding method.

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