Battery and method for manufacturing the battery

Abstract

To provide a battery capable of suppressing damage applied to other components due to a lead welded to a metal plate.SOLUTION: An axial lead 31 extending on a main surface 60a of a flat tab 60 has a body part 31c with a diameter of T0 and a connection provided from the body part to a tip 31a of the axial lead 31 to be connected to the main surface 60a. The connection includes a part 33 provided on a body part 31c side and a part 32 provided from the part 33 to the tip 31a. The part 33 includes a welded part 70 with the flat tab 60, and has a thickness T1 smaller than the diameter T0. The part 32 includes a non-welded part 71 with the flat tab 60 and has a thickness T2 equal to or less than the thickness T1. The part 32 is formed by pressing the tip 31a of the axial lead 31 rising during resistance welding with the flat tab 60. The rise of the tip 31a is deformed and disappeared by pressing, thereby suppressing damage applied to other components due to the rising tip 31a.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a battery and a method for manufacturing the battery.

Background Art

[0002] There is known a technique in which a tab serving as a terminal such as a battery element material is cut, and burrs generated at that time are pressed and crushed by a press table to avoid the burrs from damaging the battery element material and causing short circuits or defects.

[0003] Also known are a technique of pressing the side end portion of the electrode plate of an alkaline secondary battery, and a technique of suppressing the generation of burrs at the corner portion by providing an unfilled portion at the side end portion of the electrode plate using a filler and performing pressing.

[0004] Also known are a technique of obtaining a tab terminal by pressing one end portion of a metal bar into a flat plate shape, and a technique of connecting a lead wire to the other end portion of the metal bar.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in a battery, a metal plate such as a tab may be electrically connected to each or one of the positive electrode and the negative electrode, and a lead such as an axial electrical element may be connected to the metal plate by resistance welding. In such resistance welding of a lead to a metal plate, for example, in order to realize a stable welding area and current density between them, a method is adopted in which the middle part of the lead is resistance-welded to the metal plate while avoiding the tip of the lead.

[0007] In this method, although the middle part of the lead to be resistance-welded is crushed, due to the stress during welding, the tip of the lead may rise from the metal plate. Since the tip of the raised lead has a relatively sharp shape, in a battery in which the metal plate to which the lead is resistance-welded is incorporated, if other relatively flexible parts, for example, other parts such as a lead wire in which a core wire is covered with a covering material, are located on the tip of the raised lead, there is a risk of damage to the other parts and electrical defects caused thereby.

[0008] On one aspect, an object of the present invention is to realize a battery capable of suppressing damage to other parts by a lead welded to a metal plate.

Means for Solving the Problem

[0009] In one aspect, a battery is provided that includes a metal plate and a lead extending on a first main surface of the metal plate. The lead has a main body portion having a first diameter and a connection portion provided from the main body portion to the tip of the lead and connected to the first main surface. The connection portion is provided on the main body portion side and includes a welding portion with the first main surface. A first portion having a first thickness in a first direction perpendicular to the first main surface that is smaller than the first diameter, and a second portion provided from the first portion to the tip and including a non-welding portion with the first main surface, and the second thickness in the first direction before is smaller than the first thickness.

[0010] In one aspect, a method for manufacturing a battery includes arranging a lead having a first diameter so as to extend on a first main surface of a metal plate; connecting an intermediate portion between a body portion having the first diameter of the lead and a tip end of the lead to the first main surface by resistance welding; and deforming a portion including the tip end of the lead after the resistance welding by pressing toward the first main surface side.

Advantages of the Invention

[0011] In one aspect, it becomes possible to realize a battery that can suppress damage to other components caused by a lead welded to a metal plate.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiment for Carrying out the Invention

[0013] FIG. 1 is a diagram for explaining an example of a battery pack. FIG. 1 schematically shows a perspective view of the main part of an example of a battery pack. In FIG. 1, a battery pack 1A is shown as an example of a battery. The battery pack 1A shown in FIG. 1 includes three batteries (also referred to as “elementary batteries”) 10. The battery 10 group is electrically connected in series or in parallel. An electrode tab 20 is connected to the positive electrode or negative electrode (also referred to as “electrode”) 11 of each battery 10, and predetermined electrode tabs 20 are connected to each other using a lead wire or the like (not shown), and the battery 10 group is electrically connected to each other.

[0014] In the battery pack 1A, as a protection component for enhancing safety, electrical components such as a diode, a current fuse, and a PTC (Positive Temperature Coefficient) element may be connected between predetermined electrodes 11. For example, an electrical component 30 having an axial lead (also referred to as “axial lead”) 31 as shown in FIG. 1 is connected between predetermined electrodes 11.

[0015] A lead wire 40 used for connecting the battery pack 1A to an external load is connected to the electrode 11 of a predetermined battery 10 of the battery pack 1A. In addition, a covering member 50 such as an insulating tape is provided for the battery pack 1A to prevent a short circuit between predetermined batteries 10 (the electrodes 11 thereof or the electrode tabs 20 connected thereto) and a short circuit between a predetermined battery 10 and the electrical component 30.

[0016] The connection of the electrical component 30 in the battery pack 1A will be further described. The electrical element 30 has, for example, its axial lead 31 connected to a flat metal plate (also referred to as a "flat tab") 60. The electrical element 30 is mounted on the assembled battery 1A by connecting the flat tab 60 to which the axial lead 31 of the electrical element 30 is connected to the electrode 11 of a predetermined battery 10 or an electrode tab 20 connected thereto.

[0017] Here, for the connection between the axial lead 31 of the electrical element 30 and the flat tab 60, in addition to using soldering, resistance welding is used in applications where soldering cannot be used. FIG. 2 is a diagram for explaining an example of resistance welding between an axial lead and a flat tab. FIG. 2(A) schematically shows a partial plan view of an example of an axially lead and a flat tab that have been resistance welded, and FIG. 2(B) schematically shows a cross-sectional view taken along line II-II of FIG. 2(A).

[0018] In the resistance welding between the axial lead 31 of the electrical element 30 and the flat tab 60, if the range including the tip 31a of the axial lead 31 is taken as the welding area, when the welding position varies, the welding area may change, and the current density between the axial lead 31 and the flat tab 60 may change. Therefore, in the resistance welding between the axial lead 31 and the flat tab 60, a method is adopted in which an intermediate portion 31b of the axial lead 31, avoiding the tip 31a thereof, is taken as the welding area AR0. By thus taking the intermediate portion 31b of the axial lead 31 as the welding area AR0, it becomes possible to suppress the change in the welding area and the change in the current density even when the welding position varies.

[0019] When resistance welding is performed with the middle part 31b of the axial lead 31 as the welding area AR0, as shown in FIGS. 2(A) and 2(B), the middle part 31b is dented toward the main surface 60a of the flat tab 60. For example, as shown in FIG. 2(B), due to the resistance welding between the axial lead 31 with a diameter of T0 and the main surface 60a of the flat tab 60, the axial lead 31 is dented at the middle part 31b of the welding area AR0, that is, at the welded part 70. Due to such denting during resistance welding, the axial lead 31 in the welding area AR0 has a thickness T1 that is smaller than the diameter T0 of the main body part 31c that is not resistance welded. Note that the thickness T1 is the thickness of the axial lead 31 in the welding area AR0 in the direction S perpendicular to the main surface 60a of the flat tab 60.

[0020] As described above, when resistance welding is performed with the middle part 31b of the axial lead 31 as the welding area AR0, the middle part 31b is dented. On the other hand, due to the stress during resistance welding, as shown in FIG. 2(B), the tip 31a of the axial lead 31 may rise from the main surface 60a of the flat tab 60. The tip of the raised axial lead 31 has a relatively sharp shape. Therefore, in the assembled battery 1A in which the flat tab 60 to which the axial lead 31 is resistance welded is incorporated, if a relatively flexible other component is positioned on the tip 31a of the raised axial lead 31, there is a risk of damage to the other component and electrical defects caused thereby.

[0021] For example, in the assembled battery 1A, if the lead wire 40 (FIG. 1) whose core wire is covered with a covering material is positioned on the tip 31a of the raised axial lead 31, the covering material of the lead wire 40 may be damaged by the tip 31a of the axial lead 31, and its core wire may come into contact with the axial lead 31 or the flat tab 60 to which it is connected, resulting in a risk of short circuit.

[0022] In the case of the assembled battery 1A, in order to suppress damage to the coating material of such a lead wire 40, the lead wire 40 may be arranged so as not to pass over the tip 31a of the raised axial lead 31. However, adding a process for managing the position of the lead wire 40 may lead to an increase in cost. Even when the position of the lead wire 40 is managed and the lead wire 40 is arranged avoiding the tip 31a of the raised axial lead 31, the lead wire 40 may move due to vibration during transportation or use of the assembled battery 1A, and there is a risk of damage to the coating material of the lead wire 40 and a short circuit between the core wire and the axial lead 31 caused thereby. Further, it is conceivable to attach a protective component such as an insulating plate to the tip 31a of the raised axial lead 31, but there is a risk of an increase in man-hours and cost due to the addition of the protective component.

[0023] In view of the above points, here, in order to suppress the rise of the tip 31a of the axial lead 31 accompanying the resistance welding with the main surface 60a of the flat tab 60 and damage to other components such as the lead wire 40 by the tip 31a of the raised axial lead 31, a method as shown below as an embodiment is adopted.

[0024] FIG. 3 is a diagram for explaining an example of a method for forming a connection body between an axial lead and a flat tab according to an embodiment. FIG. 3(A) schematically shows a cross-sectional view of a main part of an example of a resistance welding process between an axial lead and a flat tab, and FIG. 3(B) schematically shows a cross-sectional view of a main part of an example of a pressing process of an axial lead.

[0025] In forming the connection body between the axial lead 31 and the flat tab 60, first, as shown in FIG. 3(A), resistance welding is performed between the middle part 31b of the axial lead 31 and the main surface 60a of the flat tab 60. Thereby, the axial lead 31 and the flat tab 60 are welded at the welding part 70 and integrated.

[0026] In the resistance welding between the middle part 31b of the axial lead 31 and the main surface 60a of the flat tab 60, due to the stress at that time, as shown in Fig. 3(A), the tip 31a of the axial lead 31 rises from the main surface 60a of the flat tab 60. The area including the tip 31a that has risen in this way is pressed using the press die 80 as shown in Fig. 3(B). By pressing using the press die 80, the tip 31a that rose during resistance welding is pressed against the main surface 60a side of the flat tab 60 and crushed so as to be flattened (Figs. 4 to 6, etc.).

[0027] Fig. 4 is a diagram for explaining an example of a connector between an axial lead and a flat tab according to the embodiment. Fig. 4(A) schematically shows a plan view of a main part of an example of a connector between an axial lead and a flat tab, and Fig. 4(B) schematically shows a cross-sectional view taken along the line IV-IV of Fig. 4(A).

[0028] As described above, resistance welding (Fig. 3(A)) is performed between the middle part 31b of the axial lead 31 and the main surface 60a of the flat tab 60, and then pressing (Fig. 3(B)) of the tip 31a of the axial lead 31 that has risen due to resistance welding is performed using the press die 80. Thereby, a connector between the axial lead 31 and the flat tab 60 as shown in Figs. 4(A) and 4(B), for example, is obtained.

[0029] Figs. 4(A) and 4(B) illustrate a connector obtained when pressing is performed on an area AR2 from the tip 31a of the axial lead 31 to a part of the welding area AR0 (welding part 70 formed by resistance welding) (also referred to as the "press area") using the press die 80 (Fig. 3(B)).

[0030] By resistance welding the axial lead 31 with a diameter of T0 and the main surface 60a of the flat tab 60, the axial lead 31 is crushed in the welding area AR0 (the middle part 31b and the welded part 70), and the thickness of the part of the axial lead 31 in the welding area AR0 becomes T1, which is smaller than the diameter T0 of the non-welded main body part 31c. Then, by pressing the tip 31a of the axial lead 31 that has risen due to resistance welding, the axial lead 31 is crushed in the pressing area AR2, and the thickness of the part 32 of the axial lead 31 in the pressing area AR2 becomes T2, which is smaller than the thickness T1 of the part 33 of the axial lead 31 in the non-pressed welding area (also referred to as the "non-pressed welding area") AR1 of the welding area AR0. As a result, the rise of the tip 31a of the axial lead 31 caused by resistance welding disappears.

[0031] Note that the thickness T1 is the thickness of the part 33 of the axial lead 31 in the welding area AR0 and the non-pressed welding area AR1 in the direction S perpendicular to the main surface 60a of the flat tab 60. The thickness T2 is the thickness of the part 32 of the axial lead 31 in the pressing area AR2 in the direction S perpendicular to the main surface 60a of the flat tab 60.

[0032] By pressing as described above to eliminate the rise of the tip 31a of the axial lead 31, even if a relatively flexible other component such as the lead wire 40 (Figure 1) is located on the tip 31a of the axial lead 31 in the assembled battery where the connection body of the axial lead 31 and the flat tab 60 is mounted, damage to the other component can be effectively suppressed.

[0033] In the connector between the axial lead 31 and the flat tab 60 as shown in FIGS. 4(A) and 4(B), a welding portion 70 is included in a portion 33 of the axial lead 31 in the non-press welding area AR1 on the main body portion 31c side of the axial lead 31. In a portion 32 of the axial lead 31 in the press area AR2 from the portion 33 to the tip 31a, a part of the welding portion 70 resistance-welded and connected to the main surface 60a of the flat tab 60 and a non-welded portion 71 including the tip 31a not resistance-welded are included. The non-welded portion 71 is pressed against the main surface 60a of the flat tab 60 by pressing the axial lead 31 and is brought into contact with and connected to the main surface 60a. The axial lead 31 in the non-press welding area AR1 and the press area AR2, that is, the portions 33 and 32 existing from the main body portion 31c to the tip 31a of the axial lead 31 can also be said to be the "connection portion" of the axial lead 31 connected to the main surface 60a of the flat tab 60.

[0034] In the examples of FIGS. 4(A) and 4(B) above, a range from the tip 31a of the axial lead 31 to a part of the welding area AR0 (welding portion 70 formed by resistance welding) is defined as the press area AR2, and the thickness T2 of the portion 32 of the axial lead 31 in the press area AR2 is made smaller than the thickness T1 of the portion 33 in the non-press welding area AR1. The pressing method of the axial lead 31 after resistance welding is not limited to the examples shown in FIGS. 4(A) and 4(B) above.

[0035] FIGS. 5 and 6 are diagrams for explaining modified examples of the connector between the axial lead and the flat tab according to the embodiment. FIG. 5(A) schematically shows a cross-sectional view of a main part of a first modified example of the connector between the axial lead and the flat tab. FIG. 5(B) schematically shows a cross-sectional view of a main part of a second modified example of the connector between the axial lead and the flat tab. FIG. 6(A) schematically shows a cross-sectional view of a main part of a third modified example of the connector between the axial lead and the flat tab. FIG. 6(B) schematically shows a cross-sectional view of a main part of a fourth modified example of the connector between the axial lead and the flat tab.

[0036] When pressing the axial lead 31 after resistance welding, for example, as shown in Fig. 5(A), the range from the tip 31a of the axial lead 31 to a part of the welding area AR0 (welding portion 70) may be defined as the press area AR2, and the portion 32 of the press area AR2 may be pressed so as to have the same thickness as the portion 33 of the non-pressed welding area AR1. That is, it may be pressed so that the thickness T2 of the portion 32 of the press area AR2 is the same as the thickness T1 of the portion 33 of the non-pressed welding area AR1.

[0037] In addition, when pressing the axial lead 31 after resistance welding, for example, as shown in Fig. 5(B), the entire range from the tip 31a of the axial lead 31 to the welding area AR0 (welding portion 70) may be defined as the press area AR2, and the portion 32 of the press area AR2 may be pressed so as to have a thickness T2 smaller than the thickness T1 of the portion of the welding area AR0 before pressing.

[0038] For example, the rise of the tip 31a of the axial lead 31 may be eliminated by pressing as shown in Figs. 5(A) and 5(B). Also, when pressing the axial lead 31 after resistance welding, for example, as shown in Fig. 6(A), the range from the tip 31a of the axial lead 31 to in front of the welding area AR0 (welding portion 70), that is, only the non-welding portion 71 out of the welding portion 70 and the non-welding portion 71 may be defined as the press area AR2, and the portion 32 of the press area AR2 may be pressed so as to have a thickness T2 smaller than the thickness T1 of the portion 33 of the non-pressed welding area AR1.

[0039] In addition, when pressing the axial lead 31 after resistance welding, for example, as shown in FIG. 6(B), a range from the tip 31a of the axial lead 31 to in front of the welding area AR0 (welding portion 70), that is, only the non-welded portion 71 out of the welded portion 70 and the non-welded portion 71 is defined as the press area AR2, and the portion 32 of the press area AR2 may be pressed so as to have the same thickness as the portion 33 of the non-pressed welding area AR1. That is, the thickness T2 of the portion 32 of the press area AR2 may be pressed to be the same as the thickness T1 of the portion 33 of the non-pressed welding area AR1.

[0040] For example, it is also possible to eliminate the rise of the tip 31a of the axial lead 31 by pressing as shown in FIGS. 6(A) and 6(B). If the thickness T2 of the portion 32 of the press area AR2 of the axial lead 31 is the same as or smaller than the thickness T1 of the portion 33 of the non-pressed welding area AR1 or the thickness T1 of the portion of the welding area AR0 before pressing, the rise of the tip 31a can be eliminated, and damage to other components caused by the raised tip 31a can be suppressed. However, if the thickness T2 of the portion 32 of the press area AR2 is made too small, the welding strength of the welded portion 70 may become weak. From the viewpoint of ensuring a certain level of welding strength, it is desirable to set the thickness T2 of the portion 32 of the press area AR2 of the axial lead 31 to be in the range of 50% to 100% of the thickness T1 of the portion 33 of the non-pressed welding area AR1 or the thickness T1 of the portion of the welding area AR0 before pressing.

[0041] Next, an example of a method for manufacturing a battery will be described. Here, a battery pack will be taken as an example, and an example of its manufacturing method will be described. Figs. 7 and 8 are diagrams for explaining an example of a method for manufacturing an assembled battery according to an embodiment. Fig. 7(A) schematically shows a cross-sectional view of a main part of an example of a process of arranging an axial lead of an electric element on a flat tab. Fig. 7(B) schematically shows a cross-sectional view of a main part of an example of a resistance welding process between the axial lead and the flat tab of the electric element. Fig. 7(C) schematically shows a cross-sectional view of a main part of an example of a pressing process of the axial lead of the electric element. Fig. 8(A) schematically shows a perspective view of a main part of an example of a process of mounting a connection body between the electric element and the flat tab on the assembled battery. Fig. 8(B) schematically shows a perspective view of a main part of an example of the assembled battery.

[0042] First, as shown in Fig. 7(A), an axial lead 31 (diameter T0) of an electric element 30 (Fig. 8) to be mounted on the assembled battery 1 is arranged at a predetermined position on the main surface 60a of the flat tab 60. The axial lead 31 extends and is arranged at a predetermined position on the main surface 60a such that its axial direction is parallel to the main surface 60a of the flat tab 60.

[0043] Next, as shown in Fig. 7(B), according to the example of Fig. 3(A) above, resistance welding is performed between the middle part 31b of the axial lead 31 and the main surface 60a of the flat tab 60. As a result, the axial lead 31 and the flat tab 60 are welded at the welded part 70 and integrated. In this resistance welding, as shown in Fig. 7(B), the middle part 31b of the axial lead 31 is crushed (thickness T1 (<T0)), and the tip 31a stands up from the main surface 60a of the flat tab 60.

[0044] Next, as shown in Fig. 7(C), for example, according to the examples of Fig. 3(B), Fig. 4(A), and Fig. 4(B) above, an area including the tip 31a of the standing-up axial lead 31, that is, an area including the non-welded part 71 is pressed, and the tip 31a that stood up during resistance welding is crushed and flattened toward the main surface 60a side of the flat tab 60 (thickness T2 (≦T1)). Note that the pressing of the area including the tip 31a of the axial lead 31 that stood up during resistance welding may be performed according to the examples of Fig. 5(A), Fig. 5(B), Fig. 6(A), or Fig. 6(B).

[0045] For example, a connector between the axial lead 31 with the rising edge of the tip 31a eliminated and the flat tab 60 is obtained through the processes shown in FIGS. 7(A) to 7(C). Next, as shown in FIG. 8(A), the assembled battery pack 1 is assembled. FIG. 8(A) illustrates, as an example, the assembled battery pack 1 including three cells 10 (elementary cells) electrically connected in series or in parallel. Electrode tabs 20 are connected to the electrodes 11 (positive electrodes or negative electrodes) of each cell 10 in the assembled battery pack 1, and predetermined electrode tabs 20 are connected to each other. A lead wire 40 used for connecting the assembled battery pack 1 and an external load is connected to the electrode 11 of a predetermined cell 10 in the assembled battery pack 1. In the assembled battery pack 1, as a protection component, an electrical element 30 having an axial lead 31, such as a diode, a current fuse, a PTC element, etc., is connected between predetermined electrodes 11. Further, a covering member 50 such as an insulating tape is provided in the assembled battery pack 1 to prevent a short circuit between predetermined cells 10 and a short circuit between a predetermined cell 10 and the electrical element 30.

[0046] The electrical element 30 mounted on the assembled battery pack 1 is previously prepared as a connector between the electrical element 30 and the flat tab 60 with its axial lead 31 connected to the flat tab 60 by using the method described in FIGS. 7(A) to 7(C) etc. The flat tab 60 of the prepared connector between the electrical element 30 and the flat tab 60 is connected to the electrode tab 20 connected to the electrode 11 of a predetermined cell 10, as shown in FIG. 8(A) for example, whereby the electrical element 30 is mounted on the assembled battery pack 1.

[0047] FIG. 8(B) is a diagram showing an example of the assembled battery pack 1 on which the electrical element 30 is mounted. In the assembled battery pack 1, for example, as shown by the dotted line in FIG. 8(B), the lead wire 40 may be displaced and the lead wire 40 may come into contact with the connector between the electrical element 30 and the flat tab 60. In that case, if the tip 31a of the axial lead 31 of the electrical element 30 connected to the flat tab 60 remains in the shape that has risen due to the above resistance welding, the covering material of the lead wire 40 may be damaged, and its core wire may come into contact with the axial lead 31 or the flat tab 60, resulting in a short circuit.

[0048] On the other hand, in the assembled battery 1 shown in FIG. 8(B), the tip 31a of the axial lead 31 of the electric element 30 that has risen due to the resistance welding is crushed and flattened by pressing. Therefore, for example, as shown by the dotted line in FIG. 8(B), even if the lead wire 40 is displaced and the lead wire 40 comes into contact with the connection body between the electric element 30 and the flat tab 60, the coating material of the lead wire 40 is damaged, the coating material is damaged and the core wire comes into contact with the axial lead 31 or the flat tab 60, and thus a short circuit is caused, which can be effectively suppressed.

[0049] Next, an example of the evaluation results regarding the connection body between the axial lead 31 of the electric element 30 and the flat tab 60 and the assembled battery 1 on which it is mounted will be described. (Evaluation of the connection body) FIG. 9 is a diagram for explaining an example of the evaluation of the connection body between the axial lead and the flat tab according to the embodiment. FIG. 9(A) is a schematic diagram for explaining a method of evaluating the influence on other components of the connection body between the axial lead and the flat tab before pressing the tip after resistance welding. FIG. 9(B) is a schematic diagram for explaining a method of evaluating the influence on other components of the connection body between the axial lead and the flat tab after further pressing the tip after resistance welding.

[0050] As shown in FIGS. 9(A) and 9(B), an insulating tape 90 was disposed on the connection body between the axial lead 31 and the flat tab 60, and it was pressed with a pressing die 81 from the side of the insulating tape 90, and the piercing strength of the insulating tape 90 by the tip 31a of the axial lead 31 was measured. As the insulating tape 90, an acetate tape with a base material thickness of 0.18 mm was used.

[0051] In the connection body between the axial lead 31 and the flat tab 60 before pressing the tip 31a after resistance welding as shown in FIG. 9(A), since the tip 31a of the axial lead 31 has a rising shape without being pressed, the insulating tape 90 was pierced by pressing with a relatively low pressing force of about 30 N by the pressing die 81.

[0052] On the other hand, in the connector of the axial lead 31 and the flat tab 60 in which the tip 31a is further pressed after resistance welding as shown in Fig. 9(B), since the tip 31a of the axial lead 31 is pressed and the rising is eliminated, the insulating tape 90 was not punctured even when pressed by a relatively high pressing die 81 of about 100N.

[0053] From such evaluation results, it can be said that by pressing the tip 31a of the axial lead 31 in which the middle part 31b is resistance welded to the flat tab 60 and eliminating the rising of the tip 31a, damage to other components arranged thereon can be effectively suppressed.

[0054] (Evaluation of assembled battery) Fig. 10 is a diagram for explaining an example of the evaluation of an assembled battery equipped with a connector of an axial lead and a flat tab according to the embodiment. Fig. 10 shows a schematic diagram for explaining a method of evaluating the influence of vibration of the assembled battery.

[0055] Three assembled batteries 1A each equipped with a connector of an axial lead 31 and a flat tab 60 before pressing the tip 31a after resistance welding, and three assembled batteries 1 each equipped with a connector of an axial lead 31 and a flat tab 60 in which the tip 31a is further pressed after resistance welding were prepared, and lead wires 40 were arranged on the tips 31a of the respective axial leads 31. Then, vibration was applied in the X direction, Y direction, and Z direction as shown in Fig. 10 under predetermined conditions, and the presence or absence of voltage drop due to short circuit caused by breakage of the coating material of the lead wire 40 was evaluated. The vibration conditions were 510 Hz in the X direction, 620 Hz in the Y direction, and 540 Hz in the Z direction (resonance points in each direction, 10 7 times × 3 directions).

[0056] In the assembled battery 1A equipped with a connector of an axial lead 31 and a flat tab 60 before pressing the tip 31a after resistance welding, voltage drop occurred in 2 out of 3. On the other hand, in the assembled battery 1 equipped with a connector of an axial lead 31 and a flat tab 60 in which the tip 31a was further pressed after resistance welding, no voltage drop was observed in any of the 3.

[0057] From such evaluation results, in the assembled battery 1A equipped with the connector of the axial lead 31 and the flat tab 60 before pressing the tip 31a after resistance welding, when the lead wire 40 passes over the tip 31a of the axial lead 31, breakage of its coating material and short circuits caused thereby are relatively likely to occur. On the other hand, in the assembled battery 1 equipped with the connector of the axial lead 31 and the flat tab 60 with the tip 31a further pressed after resistance welding, it can be said that even when the lead wire 40 passes over the tip 31a of the axial lead 31, breakage of its coating material and short circuits caused thereby can be effectively suppressed.

[0058] In addition, in the above description, as the assembled battery 1 equipped with the connector of the axial lead 31 and the flat tab 60 with the tip 31a pressed after resistance welding, an example including three cells 10 was shown, but the number of cells 10 is not limited to this. It is possible to mount the connector of the axial lead 31 and the flat tab 60 with the tip 31a pressed after resistance welding on an assembled battery including two or four or more cells 10. Further, the battery group constituting the assembled battery is not limited to cylindrical ones such as the above-described cell 10, and may be rectangular.

[0059] In addition, in the above description, the case of connecting the axial lead 31 to the flat tab 60 was shown as an example, but the axial lead 31 can be connected not only to the flat tab 60 but also to various metal plates such as the tab 20 for an electrode. For various metal plates, as described above, by resistance welding the middle part 31b of the axial lead 31 and deforming and disappearing the rise of the tip 31a caused thereby by pressing, damage to other components such as the coating material of the flexible lead wire 40 in contact with the tip 31a and electrical defects such as short circuits caused thereby can be suppressed.

[0060] Also, in the above description, an example method was given in which the middle part 31b of the axial lead 31 of an electrical element 30 such as a diode, a current fuse, or a PTC element is resistance-welded to a metal plate such as a flat tab 60, and the rise of the tip 31a caused thereby is deformed and eliminated by pressing. The method of performing pressing after resistance welding as described above is applicable not only to the connection between the axial lead 31 of the electrical element 30 and a metal plate such as the flat tab 60, but also to the connection between various leads and a metal plate. For example, it can be similarly applied when connecting a lead used as an external connection terminal for a single battery or a battery pack to a metal plate such as a tab connected to an electrode (positive electrode or negative electrode) of the single battery or the battery pack.

Description of Reference Numerals

[0061] 1, 1A Battery Pack 10 Battery 11 Electrode 20 Electrode Tab 30 Electrical Element 31 Axial Lead 31a Tip 31b Middle Part 31c Body Part 32, 33 Portion 40 Lead Wire 50 Coating Member 60 Flat Tab 60a Main Surface 70 Welded Part 71 Non-Welded Part 80, 81 Press Die 90 Insulating Tape AR0 Welding Area AR1 Non-Pressed Welding Area AR2 Pressing Area T0 Diameter T1, T2 Thickness

Claims

1. A metal plate, and a lead extending on a first main surface of the metal plate are provided, wherein the lead has a main body portion having a first diameter, and a connection portion provided from the main body portion to a tip of the lead and connected to the first main surface and has, the connection portion is provided on the main body portion side, includes a welding portion with the first main surface, and has a first portion in a first direction perpendicular to the first main surface, the first thickness of which is smaller than the first diameter, and a second portion provided from the first portion to the tip, includes a non-welding portion with the first main surface, and has a second thickness in the first direction, which is smaller than the first thickness and is characterized in that it includes the above. A battery characterized by this.

2. The battery according to claim 1, wherein the second thickness is a thickness of 50% or more and less than 100% of the first thickness.

3. The battery according to claim 1 or 2, wherein the second portion includes a part of the welding portion continuous from the first portion.

4. The battery according to any one of claims 1 to 3, wherein the metal plate is electrically connected to a positive electrode or a negative electrode.

5. A step of arranging a lead having a first diameter so as to extend on a first main surface of a metal plate, a step of connecting an intermediate portion between the main body portion having the first diameter of the lead and the tip to the first main surface by resistance welding, and a step of deforming a portion including the tip of the lead after the resistance welding by pressing toward the first main surface side and is characterized in that it includes the above. A method for manufacturing a battery characterized by this.

6. The method for manufacturing a battery according to claim 5, wherein the portion including the tip of the lead after the resistance welding is deformed by pressing toward the first main surface side so that the second thickness is 50% to 100% of the first thickness in a first direction perpendicular to the first main surface of the intermediate portion before the pressing, which is connected to the first main surface by the resistance welding.

7. The method for manufacturing a battery according to claim 5 or 6, wherein the portion including the tip of the lead after the resistance welding is deformed by pressing toward the first main surface side from the tip of the lead to the intermediate portion, or from the tip to a part or all of the intermediate portion.

8. The method for manufacturing a battery according to any one of claims 5 to 7, including a step of electrically connecting the metal plate to a positive electrode or a negative electrode after connecting the lead to the first main surface by the resistance welding and deforming the lead by pressing toward the first main surface side.

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