JP2019067570A - Welding jig and formation method of weld zone - Google Patents

Abstract

To provide a welding jig and a formation method of weld zone capable of restraining occurrence of breaking of uncoated part without using a protective plate.SOLUTION: A welding jig 50 has a square cylinder jig body 51, a through hole 53 penetrating the jig body 51 in the axial direction, and passes laser light, and a contact part 52 including a first pressing part 52a provided continuously to the jig body 51 in the axial direction, in contact with a tub 26 at the other end in the lamination direction, and facing the tub 26 at the other end in the lamination direction while spaced apart in a direction orthogonal to the direction of travel of the laser light. In the welding jig 50, the interval K1 of the first pressing parts 52a facing in the orthogonal direction is wider than 50 μm and narrower than 5 mm.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a welding jig and a method of forming a welding portion which are used for producing a welding portion in which a conductive member and a non-coated portion group are laser-welded.

  BACKGROUND Conventionally, in vehicles such as EVs (Electric Vehicles) and PHVs (Plug in Hybrid Vehicles), lithium ion secondary batteries and the like are mounted as power storage devices for storing power supplied to motors and the like. The secondary battery includes an electrode assembly in which a plurality of sheet-like positive electrodes and negative electrodes are alternately stacked in an insulated state, and a case for housing the electrode assembly.

  The positive electrode and the negative electrode have a metal foil, an active material layer present on both sides or one side of the metal foil, and an uncoated portion where the active material layer is not present and the metal foil is exposed. The uncoated portion is, for example, a tab protruding from one side of the metal foil. The electrode assembly includes tabs as uncoated portions in which tabs of each polarity are stacked. Power extraction from the secondary battery is performed through an electrode terminal electrically connected to the electrode assembly. The electrode assembly and the electrode terminal are electrically connected by welding a conductive member to the tab group and the electrode terminal.

  By the way, in welding of the tab group and the conductive member, as the number of tabs constituting the tab group increases, the penetration depth in the stacking direction of the tabs when welding all the tabs at one time becomes deeper, so it is necessary for welding The energy of the laser light is increased. In this case, a break may occur in the tabs close to the irradiation position of the laser light in the tab group. On the other hand, in Patent Document 1, for example, the tab group is sandwiched between the protective plate and the conductive member and laser welding is performed to suppress breakage of the tab at the time of welding.

JP, 2016-002566, A

  However, since the protective plate is welded to the tabs when welding the tabs to the conductive member, the protective plate is required each time the tabs and the conductive member are welded. In addition, the protective plate leads to an increase in the number of parts of the secondary battery.

  An object of the present invention is to provide a welding jig and a method of forming a welding portion which can suppress the occurrence of breakage of an uncoated portion without using a protective plate.

  A welding jig for solving the above problems has a positive electrode layer having an active material layer on at least one surface of a metal foil, and a positive electrode having an uncoated portion on which the metal foil is exposed without the presence of the active material layer An electrode assembly comprising an uncoated portion group having a structure in which an electrode of a negative electrode is insulated and the uncoated portions are laminated with the same polarity; and the uncoated portion group A power storage device comprising: a conductive member joined thereto, the welding jig being used for manufacturing a welded portion in which the conductive member and the uncoated portion group are laser-welded, wherein the welded portion is The conductive member is disposed outside the uncoated portion at one end in the stacking direction of the uncoated portion group, and the welding jig placed on the uncoated portion at the other end in the stacking direction of the uncoated portion group Laser light passing through the welding jig in a state where the uncoated portion group is pressurized in the stacking direction The uncoated portion at the other end of the lamination direction is irradiated while being moved in the advancing direction, and the welding jig is formed to penetrate the cylindrical jig body and the jig body in the axial direction, The laser beam is provided continuously in the axial direction of the jig body with a through hole through which a laser beam passes, is in contact with the uncoated portion at the other end in the stacking direction, and the uncoated portion at the other end in the stacking direction And a contact portion provided with opposing portions separated in a direction orthogonal to the traveling direction, and an interval between the opposing portions is greater than 50 μm and 5 mm or less.

  According to this, by pressing the non-coated portion group by the welding jig, in the non-coated portion group, the portion sandwiched in the range of 50 μm or more and 5 mm or less is stretched and adjacent in the stacking direction Unmatched uncoated parts can be in close contact with each other. For this reason, in the case of laser welding, if laser light is allowed to pass through the welding jig, melting easily proceeds in the entire laminating direction of the uncoated portion group, and the uncoated portion close to the laser beam irradiation position (laminating direction It is suppressed that energy concentrates on the uncoated part on the other end side. Therefore, generation | occurrence | production of the tear of an uncoated part can be suppressed by the structure without a protective plate.

Further, in the welding jig, the contact portion is preferably cylindrical.
According to this, it can suppress that the sputter | spatter which generate | occur | produced by irradiation of a laser beam disperses out of the jig for welding by a contact part.

Further, in the welding jig, the welding jig is preferably made of a ceramic.
According to this, for example, compared with the case where the welding jig is made of metal, it is easy to lower the thermal conductivity of the welding jig. For this reason, it is easy to suppress that the heat | fever at the time of laser welding is transmitted to a jig for welding, and is thermally radiated, and it is easy to suppress the efficiency fall of laser welding.

  The method of forming a weld for solving the above problems has an active material layer on at least one side of a metal foil, and an uncoated part where the active material layer does not exist and the metal foil is exposed. An electrode assembly comprising an uncoated portion group in which the positive and negative electrodes are laminated in an insulated state and the uncoated portions are laminated with the same polarity, and the uncoated portion is bonded And a method of forming a welded portion in which the conductive member and the uncoated portion group are laser-welded, and the uncoated portion at one end in the stacking direction of the uncoated portion group. A welding jig is disposed, in which the conductive member is disposed outside and the uncoated portion at the other end in the stacking direction of the uncoated portion group passes a laser beam, and the contact portion of the welding jig 50 μm for the part facing away from and orthogonal to the direction of travel of the laser light The uncoated portion is brought into contact with the uncoated portion at the other end in the layering direction of the uncoated portion while leaving a gap of 5 mm or less, and the uncoated portion is pressed in the laminating direction by the welding jig. In the state, while moving the laser beam passing through the welding jig in the traveling direction, the non-coated portion at the other end in the stacking direction is irradiated.

  According to this, by bringing the contact portion of the welding jig into contact with the uncoated portion group and applying pressure, in the uncoated portion group, a portion sandwiched by the contact portion in a range of 50 μm or more and 5 mm or less It can be in a stretched state, and the uncoated portions adjacent in the stacking direction can be in close contact with each other. For this reason, when forming a welded portion by laser welding, melting easily proceeds in the entire laminating direction of the uncoated portion group, and the uncoated portion (uncoated on the other side in the laminating direction) is closer to the irradiation position of the laser light. The concentration of energy in the engineering department is suppressed. Therefore, generation | occurrence | production of the tear of an uncoated part can be suppressed by the structure without a protective plate.

In addition, in the method of forming a weld, the contact portion is preferably cylindrical.
According to this, it can suppress that the sputter | spatter which generate | occur | produced by irradiation of a laser beam disperses out of the jig for welding by a contact part.

In addition, in the method of forming a welded portion, when the uncoated portion group is pressurized by the welding jig, it is preferable to apply a pressure of 1 to ² kgf / cm ² .
According to this, the conductive member disposed outside the uncoated portion at one end in the laminating direction of the uncoated portion group can be suppressed from being bent by the pressure, and the uncoated portion is stretched by the pressure. Can be

  According to the present invention, it is possible to suppress the occurrence of breakage of the uncoated portion even without using a protective plate.

BRIEF DESCRIPTION OF THE DRAWINGS The disassembled perspective view which shows the secondary battery of embodiment. The fragmentary sectional side view showing the rechargeable battery of an embodiment. (A) is sectional drawing which shows the welding part in the state which extended the tab group, (b) is a top view which shows the welding part in the state which extended the tab group, (c) is a figure which shows a motion of a laser beam. (A) is a perspective view which shows the jig for welding, (b) is sectional drawing which shows the jig for welding. The perspective view which shows the state which pressed the jig for welding by the air cylinder. The figure which shows the state which performs laser welding. The top view which shows the jig and welding part for welding.

Hereinafter, one embodiment which materialized a jig for welding is described according to Drawings 1-7.
As shown in FIG. 1 or 2, the secondary battery 10 as a power storage device includes a case 11. The secondary battery 10 includes an electrode assembly 12 housed in a case 11 and an electrolyte (not shown). The case 11 has a rectangular parallelepiped case body 13 and a rectangular flat lid 14 closing the opening 13 a of the case body 13. The case main body 13 and the lid 14 constituting the case 11 are both made of metal (for example, stainless steel or aluminum). Moreover, the secondary battery 10 of the present embodiment is a square battery whose appearance is square. In addition, the secondary battery 10 of the present embodiment is a lithium ion battery.

  The secondary battery 10 includes a pair of electrode terminals 15 for extracting electricity from the electrode assembly 12. Of the pair of electrode terminals 15, one electrode terminal 15 is a positive electrode terminal, and the other electrode terminal 15 is a negative electrode terminal. Each electrode terminal 15 penetrates the hole 14 a of the lid 14 and protrudes out of the case 11. A ring-shaped insulating ring 16 for insulating the lid 14 is attached to each of the electrode terminals 15. Each electrode terminal 15 has a rectangular plate-like conductive member 17 in the case 11. Each electrode terminal 15 is joined to the conductive member 17, and the electrode assembly 12 and the electrode terminal 15 are electrically connected via the conductive member 17.

  The electrode assembly 12 includes a positive electrode 21 as a plurality of sheet-like positive electrodes and a negative electrode 22 as a plurality of sheet-like negative electrodes. The electrode assembly 12 has a layered structure which is alternately stacked in a state in which the separator 23 is interposed between the positive electrode 21 and the negative electrode 22 for insulation.

  The positive electrode 21 and the negative electrode 22 are provided with a metal sheet 24 in the form of a rectangular sheet. The metal foil 24 of the positive electrode 21 is, for example, an aluminum foil, and the metal foil 24 of the negative electrode 22 is, for example, a copper foil. The positive electrode 21 and the negative electrode 22 have active material layers 25 present on both sides of the metal foil 24. The active material layer 25 contains an active material, a conductive material, and a binder according to the polarity. The positive electrode 21 and the negative electrode 22 have rectangular tabs 26 protruding from a part of one of the edges along the pair of long sides. In the present embodiment, the longitudinal direction of the tab 26 coincides with the projecting direction of the tab 26 from the edge. The tab 26 is an uncoated portion where the active material layer 25 does not exist and the metal foil 24 is exposed.

  The electrode assembly 12 is a tab group 18 as an uncoated portion group in which the tab 26 of each positive electrode 21 is collected at one end in the direction in which the positive electrode 21, the negative electrode 22, and the separator 23 are stacked. Equipped with Similarly, in the electrode assembly 12, the tab 26 of each negative electrode 22 is collected at one end in the direction in which the positive electrode 21, the negative electrode 22, and the separator 23 are stacked, and then stacked. A tab group 18 is provided. The direction in which the tabs 26 are stacked is referred to as the stacking direction. Each tab group 18 is present on the end face 12 a facing the lid 14 in the electrode assembly 12. The electrode assembly 12 is accommodated in the case 11 in a state where the proximal end and the distal end of the tab group 18 in the protruding direction of the tab 26 are bent. In FIG. 3 and later, for convenience of explanation, the tab group 18 is illustrated in a state of being extended without being bent.

  As shown in FIGS. 3A and 3B, the secondary battery 10 includes a welding portion 31. As shown in FIG. 3A, the welding portion 31 is formed by laser welding all the tabs 26 in the stacking direction. The stacking direction of the tab group 18 is the vertical direction, one end in the stacking direction of the tab group 18 is the lower end, and the other end in the stacking direction is the upper end. When the tab group 18 is viewed from the other end side (upper side) in the stacking direction, the welding portion 31 is in the form of a linearly extending strip. The longitudinal length of the weld 31 extends in the lateral direction of the tab 26. The length in the longitudinal direction of the welded portion 31 is set to 10 mm, for example, if the length in the lateral direction of the tab 26 is 22 mm, and the length in the lateral direction of the welded portion 31 is 1.0 mm, for example Set to The length of weld 31 in the longitudinal direction may be appropriately changed as long as it is within the range of the length of tab 26 in the lateral direction, and the length in the lateral direction of weld 31 is The length of the tab 26 in the longitudinal direction may be changed as appropriate.

  As shown in FIG. 3C, the welding portion 31 reciprocates the laser beam R having a spot diameter of 50 μm in the longitudinal direction of the tab 26 (the transverse direction of the welding portion 31). It is made to move in the direction (longitudinal direction of the welding portion 31). In the present embodiment, the longitudinal direction of the welding portion 31 is the traveling direction of the laser beam R, and the lateral direction of the welding portion 31 is the orthogonal direction to the traveling direction.

Next, a method of forming a weld using a welding jig will be described.
The method of forming a weld includes a foil collecting step, a pressing step, and a welding step.
The foil collecting step is a step of collecting the plurality of tabs 26 provided in the electrode assembly 12 to form the tab group 18. In the foil collection step, as shown in FIG. 5 or 6, all the tabs 26 of the electrode assembly 12 are disposed on the conductive member 17 placed on the work bench S. That is, the conductive member 17 is disposed outside (below) the tab 26 at one end in the stacking direction.

  The conductive member 17 is already joined to the electrode terminal 15, and the electrode terminal 15 is fastened to the lid 14, and the conductive member 17 is integrated with the lid 14. Therefore, as shown in FIG. 6, the conductive member 17 is supported in a cantilever manner in a state of being slightly separated from the lid 14. When the tabs 26 are disposed on the conductive member 17, all the tabs 26 are disposed on the conductive member 17 cantilevered on the lid 14. Next, all the tabs 26 are pressed from the opposite side (the other end side in the stacking direction) of the conductive members 17 sandwiching the tabs 26 with a foil collector (not shown) to form the tab group 18.

The pressing step is a step of pressing the tab group 18 from the other end in the stacking direction. A welding jig 50 is used in the pressurizing step. Here, the welding jig 50 will be described.
The welding jig 50 is made of a ceramic, and examples of the ceramic include machinable ceramics and silicon nitride. The machinable ceramic is a machinable ceramic which is easily machined by combining mica or the like. In this embodiment, as machinable ceramics, those having low thermal conductivity and high thermal shock resistance are used. For example, Photoveil (registered trademark) mainly composed of SiO ₂ · AlO ₂ , AlN ··· One that contains BN as a main component is Shapal M Soft (registered trademark).

  As shown in FIG. 4 (a) or FIG. 4 (b), the welding jig 50 has a rectangular cylindrical shape. In the welding jig 50, the direction in which the central axis L of the square tube extends is taken as the axial direction. The welding jig 50 includes a square cylindrical jig main body 51 on one end side in the axial direction, and a square cylindrical contact portion 52 on the other end side in the axial direction. Thus, the contact portion 52 is axially connected to the jig body 51. The welding jig 50 is provided with a through hole 53 penetrating in the axial direction. The through holes 53 allow the laser beam R to pass through at the time of laser welding. Therefore, the welding portion 31 is formed at a position surrounded by the welding jig 50 in the tab group 18. The jig body 51 and the contact portion 52 have a quadrangular frame shape in a plan view when viewed in the axial direction, and the through holes 53 have a rectangular shape in a plan view. The through hole 53 is partitioned by the inner side surface of the jig body 51 and the inner side surface of the contact portion 52. The length in the longitudinal direction and the length in the lateral direction of the through holes 53 are the same in the axial direction.

  As shown in FIG. 7, the contact portion 52 extends in the longitudinal direction of the square frame, and a pair of first pressing portions 52a facing each other, and a pair of second sides extending in the width direction of the square frame and facing each other And a pressing portion 52b. In a plan view, the first pressing portion 52a and the second pressing portion 52b extend linearly. One second pressing portion 52b is connected to one longitudinal end of the pair of first pressing portions 52a, and the other second pressing portion 52b is connected to the other longitudinal end of the pair of first pressing portions 52a. .

  As shown in FIG. 5 or 6, the welding jig 50 having the above configuration is placed on the tab 26 which is the uncoated portion at the other end (upper end) in the stacking direction, and presses the tab group 18 in the stacking direction. Used for As shown in FIG. 7, the welding portion 31 is formed in a shape in which the longitudinal direction extends in the short direction of the tab 26. That is, the welding portion 31 is formed inside the welding jig 50 so that the longitudinal direction extends in the longitudinal direction of the through hole 53 of the welding jig 50. For this reason, the welding jig 50 is placed on the tab 26 in a state in which the longitudinal direction of the first pressing portion 52 a extends in the short direction of the tab 26.

  The distance K1 between the facing surfaces of the pair of first pressing portions 52a is set to 5 mm or less, which is wider than 50 μm. The distance K1 between the first pressing portions 52a is the length of a straight line connecting the facing surfaces of the first pressing portions 52a at the shortest distance. As described above, since the welding portion 31 is formed by moving the laser beam R having a spot diameter of 50 μm in the traveling direction, the welding portion 31 should be reciprocated in the lateral direction of the welding portion 31. The minimum value of the length in the short direction of is the spot diameter. If the distance K1 of the first pressing portions 52a is 50 μm or less, the laser light R contacts each of the first pressing portions 52a during laser welding, which is not preferable. Therefore, the interval K1 of the first pressing portion 52a is set wider than 50 μm.

  In addition, when pressing the tab group 18 with the welding jig 50, the first pressing portion 52a is used to suppress separation of the adjacent tabs 26 in the stacking direction, that is, to closely contact the tabs 26. The inventors have confirmed that it is preferable that the distance K1 of the distance is 5 mm or less. That is, when the distance K1 between the first pressing portions 52a is larger than 5 mm, it becomes difficult to bring the adjacent tabs 26 in the stacking direction into close contact with each other even if the tab group 18 is pressed by the welding jig 50. . Therefore, the space | interval of the 1st press part 52a is set to 5 mm or less.

  Also, as described above, the welding portion 31 is formed by moving the laser beam R in the advancing direction inside the welding jig 50, but the advancing direction of the laser beam R is the longitudinal direction of the welding portion 31 is there. Therefore, a pair of 1st press part 52a will be located apart in the orthogonal direction with respect to the advancing direction of the welding part 31. As shown in FIG. Therefore, the pair of first pressing portions 52 a of the contact portion 52 are portions facing apart in the direction orthogonal to the traveling direction of the laser beam R.

  In addition, it is preferable that the thickness of the 1st press part 52a is set to 0.1-6 mm. This is because, for example, when the length in the short direction of the conductive member 17 is 17 mm, the dimension in the area where the welded portion 31 can be formed in the tab group 18, that is, the area overlapping the conductive member 17 is also 17 mm. In the region of the tab group 18 overlapping the conductive member 17, 5 mm which is the maximum value of the space K1 is secured, and in order to bring the pair of first pressing portions 52a into contact with the tab 26, (17-5) ÷ 2 to 6 mm Is calculated as the maximum value. On the other hand, the minimum value 0.1 mm is set as the minimum thickness required to press the tab group 18.

  The distance K2 between the facing surfaces of the pair of second pressing portions 52b is set according to the length in the longitudinal direction of the welding portion 31 so that the laser beam R does not contact the second pressing portions 52b. For example, the interval K2 of the second pressing portion 52b is set such that a gap of a predetermined size (for example, 2 mm) or more is formed between the end in the longitudinal direction of the welding portion 31 and the inner surface of the second pressing portion 52b. Be done. In addition, the space | interval K2 of the 2nd press part 52b is the length of the straight line which ties the opposing surfaces of the 2nd press part 52b by shortest distance.

  The welding jig 50 is provided with a contact surface 54 to the tab 26 on the end surface (lower surface) of the contact portion 52. The contact surface 54 is formed in a square frame shape from the end surfaces of the pair of first pressing portions 52 a and the end surfaces of the pair of second pressing portions 52 b. The area of the contact surface 54 is smaller than the area of the end surface (upper surface) of the jig body 51.

  As shown in FIG. 5 or 6, the welding jig 50 is connected to the fluid cylinder 60, and the welding jig 50 is supported by the fluid cylinder 60 so as to be vertically movable. The fluid cylinder 60 is an air cylinder. The fluid cylinder 60 includes a cylinder tube 60a and a cylinder rod 60b which protrudes and retracts from the lower end of the cylinder tube 60a. A piston 60c is movably accommodated in the cylinder tube 60a, and one end of a cylinder rod 60b is connected to the piston 60c. A welding jig 50 is connected to the other end which is a projecting end of the cylinder rod 60b from the cylinder tube 60a. Then, by pressing the welding jig 50 placed on the tab group 18 toward the tab group 18 by the fluid cylinder 60, the tab group 18 can be pressurized in the stacking direction by the welding jig 50.

  Then, by pressing the tab group 18 with the welding jig 50, it is possible to press the periphery of the portion to be the welding portion 31 in the tab group 18. The pair of first pressing parts 52a can press a part facing away from and in the direction orthogonal to the traveling direction of the laser light R, and the pair of second pressing parts 52b separates on both sides in the traveling direction of the laser light R Can be pressurized. By pressing the group of tabs 18 with the welding jig 50, each tab 26 can be stretched around the portion to be the welding portion 31, and the slack of the tab 26 at the portion to be the welding portion 31 can be suppressed. .

The pressure of the tab group 18 adjusts the pressure of the fluid cylinder 60 so as to be 1 to ² kgf / cm ² . In addition, when the pressure is smaller than 1 kgf / cm ² , it is difficult to make each tab 26 tensioned, which is not preferable. On the other hand, when the applied pressure becomes larger than 2 kgf / cm ^2, in the conductive member 17 disposed on the outer side (lower side) of the tab group 18 and supported in a cantilever manner by the lid 14, a portion not supported by the lid 14 is bent. There is a risk of failure.

  Then, in the pressing step, the welding jig 50 is placed on the tab 26 positioned at the other end of the tab group 18 in the stacking direction, and the contact surface 54 is brought into contact with the tab 26 at the other end in the stacking direction. At this time, in the tab 26, the contact surface 54 is brought into contact with a position surrounding a portion where the weld portion 31 is to be formed. Next, the fluid jig 60 is moved by the fluid cylinder 60 toward the tab group 18. Then, in the tab group 18, the periphery of the portion to be the welding portion 31 is pressurized by the welding jig 50. As a result, in the tab group 18, the tabs 26 adjacent in the stacking direction are in close contact with each other.

  As shown in FIG. 6, the welding process is a process of forming the welding portion 31. The welding process is performed by laser welding. The laser beam R is irradiated to the through hole 53 of the welding jig 50 pressing the tab group 18 by the laser irradiation apparatus 62, and the laser beam R is allowed to pass through the through hole 53. That is, the laser beam R is applied to the tab 26 at the other end of the tab group 18 in the stacking direction. Then, as shown in FIG. 3C, the laser beam R is moved in the traveling direction. At this time, by pressurizing the tab group 18 with the welding jig 50, each tab 26 is pulled between the first pressing portions 52a in the tab group 18 and becomes in a stretched state. As a result, laser welding is performed in a state in which the adjacent tabs 26 in the stacking direction are in close contact with each other, and the welded portion 31 is formed.

Next, the effects of the present embodiment will be described.
(1) In the contact portion 52 of the welding jig 50, the distance K1 between the pair of first pressing portions 52a was set to be wider than 50 μm and 5 mm or less. For this reason, when the tab group 18 is pressurized by the welding jig 50, in the tab 26, the portion sandwiched by the pair of first pressing portions 52a can be stretched. As a result, the welding portion 31 can be formed by causing the laser beam R to pass through the welding jig 50 while keeping the tabs 26 adjacent in the stacking direction in close contact with each other. For this reason, melting tends to proceed in the stacking direction, and concentration of energy on the tab 26 close to the irradiation position of the laser beam R is suppressed. Therefore, the occurrence of breakage of the tab 26 can be suppressed without using a protective plate. As a result, as compared with the case where a protective plate is used for each time of laser welding of the tab group 18 and the conductive member 17, the welding process becomes easier and the number of parts of the secondary battery 10 does not increase.

  (2) The area of the contact surface 54 is made smaller than the area of the upper surface of the jig body 51, and the area in contact with the tab 26 is made smaller. Therefore, for example, as compared with the case where the welding jig 50 is brought into contact with the entire peripheral surface of the welding portion 31 in the tab 26, the pressing force is concentrated around the welding portion 31, and the fluid cylinder 60 The pressing force generated when pressing the key can be increased.

(3) The contact portion 52 is in the shape of a square tube and surrounds the weld portion 31. For this reason, it can suppress that the sputter | spatter which arose at the time of laser welding disperses outside the contact part 52. FIG.
(4) The contact portion 52 is in the shape of a square tube and surrounds the weld portion 31. For this reason, in the tab group 18, the portion to be the welding portion 31 can be annularly pressurized, and the tab 26 can be easily made to be in a state of tension.

  (5) The welding jig 50 is made of ceramics having a low thermal conductivity and high thermal shock resistance. Therefore, the heat radiation during laser welding can be suppressed by the welding jig 50. Further, even if the temperature of the welding jig 50 rapidly rises due to the heat at the time of laser welding, it is possible to suppress the welding jig 50 from being broken or having a crack.

(6) When pressing the tab group 18 with the welding jig 50, the pressing force was set to 1 to ² kgf / cm ² . For this reason, the slack of the tab 26 can be suppressed without bending the conductive member 17 disposed under the tab group 18.

The above embodiment may be modified as follows.
○ When each tab 26 can be stretched when the tab group 18 is pressurized by the welding jig 50, the pressure applied to the tab group 18 by the welding jig 50 is not 1 to ² kgf / cm ² It may be set to

  The contact portion 52 may not have a square cylindrical shape. For example, the contact portion 52 may be changed to a cylindrical shape, an elliptic cylindrical shape, a hexagonal cylindrical shape, or the like as long as it can surround a portion to be the welding portion 31 in the tab group 18.

The jig body 51 and the contact portion 52 of the welding jig 50 may be separate members.
The contact portion 52 may not be cylindrical. For example, the contact portion may be configured to include only the pair of first pressing portions 52a as a portion facing away from and in the direction orthogonal to the traveling direction of the laser beam R. The point is that the contact portion may be C-shaped or U-shaped in a plan view as long as the contact portion includes portions opposed and opposed in the orthogonal direction to the traveling direction of the laser beam R.

  The electrode assembly 12 may be a wound electrode assembly. Although not shown, the wound electrode assembly has a layered structure in which a long strip-like positive electrode and a long strip-like negative electrode are insulated and wound. The positive electrode and the negative electrode each have a strip-like uncoated portion in which the metal foil is exposed without an active material layer present at one of the edges along the pair of long sides. The electrode assembly includes an uncoated portion group in which strip-shaped uncoated portions are stacked with the same polarity. The uncoated portion group of the positive electrode is present at one end of the winding axis, and the uncoated portion group of the negative electrode is present at the other end of the winding axis.

In the positive electrode 21 and the negative electrode 22, the active material layer 25 may be present on one side of the metal foil 24.
The uncoated portions of the positive electrode 21 and the negative electrode 22 are not limited to the tab 26. For example, the metal foil 24 is exposed from one of the edges along the pair of long sides of the positive electrode 21 and the negative electrode 22, and the tab 26 is protruded from a part of the exposed metal foil. Then, the metal foil and the tab 26 along the edge may be an uncoated part. Alternatively, the metal foil 24 may be exposed from one of the edge portions along the pair of long sides of the positive electrode 21 and the negative electrode 22, and only the exposed portion may be an uncoated portion.

The welding jig 50 may be a ceramic other than machinable ceramics, or may be a metal having a low thermal conductivity and a high thermal shock resistance.
The longitudinal direction of the welding portion 31 may extend in the longitudinal direction of the tab 26.

The length of the weld 31 in the longitudinal direction may be changed as appropriate.
The shape of the welding portion 31 may be changed as appropriate.
The power storage device is also applicable to power storage devices other than secondary batteries, such as capacitors.

  The secondary battery 10 may be another secondary battery other than a lithium ion secondary battery. The point is that the ions move between the active material for the positive electrode and the active material for the negative electrode and the charge is taught.

  DESCRIPTION OF SYMBOLS R ... Laser beam, K1 ... space | interval, 10 ... Secondary battery as an electrical storage apparatus, 12 ... Electrode assembly, 17 ... Conducting member, 18 ... Tab group as uncoated part group, 21 ... Positive electrode as an electrode of a positive electrode Electrode 22 Negative electrode as electrode of negative electrode 24 Metal foil 25 Active material layer 26 Tab as uncoated portion 31 Welded portion 50 Jig for welding 51 Jig main body , 52 ... contact portion, 53 ... through hole.

Claims (6)

A structure in which an active material layer is provided on at least one side of a metal foil, and the positive and negative electrodes having an uncoated portion where the active material layer is not present and the metal foil is exposed are laminated in an insulated state An electric storage apparatus comprising: an electrode assembly including an uncoated portion group having the uncoated portions stacked in the same polarity, and a conductive member joined to the uncoated portion group. A welding jig used for manufacturing a welded portion in which a conductive member and the uncoated portion group are laser welded.
The said welding part arrange | positioned the said conductive member outside the uncoated part of the lamination direction one end of the said uncoated part group, and mounted on the uncoated part of the lamination direction other end of the said uncoated part group In a state where the uncoated portion group is pressed in the stacking direction by the welding jig, the uncoated portion at the other end in the stacking direction is irradiated while moving the laser beam passing through the welding jig in the traveling direction It is formed by
The welding jig is
A cylindrical jig body,
A through hole which penetrates the jig body in the axial direction and allows the laser beam to pass through;
It is continuously provided in the axial direction of the jig body, contacts the uncoated portion at the other end in the laminating direction, and is separated in the orthogonal direction to the traveling direction of the laser light at the uncoated portion at the other end And a contact portion provided with opposing portions,
A welding jig characterized in that an interval between the opposing parts is more than 50 μm and 5 mm or less.   The welding jig according to claim 1, wherein the contact portion is cylindrical.   The welding jig according to claim 1, wherein the welding jig is made of a ceramic. An electrode of a positive electrode and a negative electrode having an active material layer on at least one surface of a metal foil and an uncoated portion where the active material layer is not present and the metal foil is exposed are laminated in a state of being insulated In a power storage device, comprising: an electrode assembly including an uncoated portion group in which the uncoated portions are stacked with the same polarity; and a conductive member joined to the uncoated portion group, the conductive member and the conductive member. It is a formation method of the welding part which carried out the laser welding with the uncoated part group,
The conductive member is disposed outside the uncoated portion at one end in the stacking direction of the uncoated portion group, and laser light is allowed to pass through the uncoated portion at the other end in the stacking direction of the uncoated portion. Put the jig,
At the contact portion of the welding jig, the other portion in the stacking direction of the uncoated portion group is spaced apart in a direction orthogonal to the traveling direction of the laser light, with the portions facing each other wider than 50 μm and spaced 5 mm or less. In the state where the uncoated portion is brought into contact with the uncoated portion and the uncoated portion group is pressed in the laminating direction by the welding jig, the laminating direction is moved while moving the laser beam passing through the welding jig in the advancing direction A method of forming a welded portion comprising irradiating the uncoated portion at the other end.   The method according to claim 4, wherein the contact portion is cylindrical. The method for forming a welded portion according to claim 4 or 5, wherein the uncoated portion group is pressurized by a pressure of 1 to ² kgf / cm ² when the uncoated portion group is pressurized by the welding jig.